Evaluating the effect of different draw solutes in a baffled osmotic membrane bioreactor-microfiltration using optical coherence tomography with real wastewater.

PubMed

Pathak, Nirenkumar; Fortunato, Luca; Li, Sheng; Chekli, Laura; Phuntsho, Sherub; Ghaffour, Noreddine; Leiknes, TorOve; Shon, Ho Kyong

2018-05-02

This study investigated the performance of an integrated osmotic and microfiltration membrane bioreactor for real sewage employing baffles in the reactor. To study the biofouling development on forward osmosis membranes optical coherence tomography (OCT) technique was employed. On-line monitoring of biofilm growth on a flat sheet cellulose triacetate forward osmosis (CTA-FO) membrane was conducted for 21 days. Further, the process performance was evaluated in terms of water flux, organic and nutrient removal, microbial activity in terms of soluble microbial products (SMP) and extracellular polymeric substance (EPS), and floc size. The measured biofouling layer thickness was in the order sodium chloride (NaCl) > ammonium sulfate (SOA) > potassium dihydrogen phosphate (KH 2 PO 4 ). Very high organic removal (96.9 ± 0.8%) and reasonably good nutrient removal efficiency (85.2 ± 1.6% TN) was achieved. The sludge characteristics and biofouling layer thickness suggest that less EPS and higher floc size were the governing factors for less fouling. Copyright © 2018 Elsevier Ltd. All rights reserved.

Slippery liquid-infused porous surface bio-inspired by pitcher plant for marine anti-biofouling application.

PubMed

Wang, Peng; Zhang, Dun; Lu, Zhou

2015-12-01

Marine biofouling, caused by the adhesion of microorganism, is a worldwide problem in marine systems. In this research work, slippery liquid-infused porous surface (SLIPS), inspired by Nepenthes pitcher plant, was constructed over aluminum for marine anti-biofouling application. The as-fabricated SLIPS was characterized with SEM, AFM, and contact angle meter. Its anti-biofouling performance was evaluated with settlement experiment of a typical marine biofouling organism Chlorella vulgaris in both static and dynamic conditions. The effect of solid substrate micro-structure on anti-biofouling property of SLIPS was studied. It was suggested that the micro-structure with low length scale and high degree of regularity should be considered for designing stable SLIPS with exceptional anti-biofouling property. The liquid-like property is proven to be the main contributor for the exceptional anti-biofouling performance of SLIPS in both static and dynamic conditions. The low roughness, which facilitates removing the settled C. vulgaris under shear force, is also a main contributor for the anti-biofouling performance of SLIPS in dynamic condition. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparison of biofouling mechanisms between cellulose triacetate (CTA) and thin-film composite (TFC) polyamide forward osmosis membranes in osmotic membrane bioreactors.

PubMed

Wang, Xinhua; Zhao, Yanxiao; Yuan, Bo; Wang, Zhiwei; Li, Xiufen; Ren, Yueping

2016-02-01

There are two types of popular forward osmosis (FO) membrane materials applied for researches on FO process, cellulose triacetate (CTA) and thin film composite (TFC) polyamide. However, performance and fouling mechanisms of commercial TFC FO membrane in osmotic membrane bioreactors (OMBRs) are still unknown. In current study, its biofouling behaviors in OMBRs were investigated and further compared to the CTA FO membrane. The results indicated that β-D-glucopyranose polysaccharides and microorganisms accounted for approximately 77% of total biovolume on the CTA FO membrane while β-D-glucopyranose polysaccharides (biovolume ratio of 81.1%) were the only dominant biofoulants on the TFC FO membrane. The analyses on the biofouling structure implied that a tighter biofouling layer with a larger biovolume was formed on the CTA FO membrane. The differences in biofouling behaviors including biofoulants composition and biofouling structure between CTA and TFC FO membranes were attributed to different membrane surface properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

Targeting N-acyl-homoserine-lactones to mitigate membrane biofouling based on quorum sensing using a biofouling reducer.

PubMed

Siddiqui, Muhammad Faisal; Sakinah, Mimi; Singh, Lakhveer; Zularisam, A W

2012-10-31

Exploring novel biological anti-quorum sensing (QS) agents to control membrane biofouling is of great worth in order to allow sustainable performance of membrane bioreactors (MBRs) for wastewater treatment. In recent studies, QS inhibitors have provided evidence of alternative route to control membrane biofouling. This study investigated the role of Piper betle extract (PBE) as an anti-QS agent to mitigate membrane biofouling. Results demonstrated the occurrence of the N-acyl-homoserine-lactone (AHL) autoinducers (AIs), correlate QS activity and membrane biofouling mitigation. The AIs production in bioreactor was confirmed using an indicator strain Agrobacterium tumefaciens (NTL4) harboring plasmid pZLR4. Moreover, three different AHLs were found in biocake using thin layer chromatographic analysis. An increase in extracellular polymeric substances (EPS) and transmembrane pressure (TMP) was observed with AHL activity of the biocake during continuous MBR operation, which shows that membrane biofouling was in close relationship with QS activity. PBE was verified to mitigate membrane biofouling via inhibiting AIs production. SEM analysis further confirmed the effect of PBE on EPS and biofilm formation. These results exhibited that PBE could be a novel agent to target AIs for mitigation of membrane biofouling. Further work can be carried out to purify the active compound of Piper betle extract to target the QS to mitigate membrane biofouling. Copyright © 2012 Elsevier B.V. All rights reserved.

Effect of calcium ions on the evolution of biofouling by Bacillus subtilis in plate heat exchangers simulating the heat pump system used with treated sewage in the 2008 Olympic Village.

PubMed

Tian, Lei; Chen, Xiao Dong; Yang, Qian Peng; Chen, Jin Chun; Shi, Lin; Li, Qiong

2012-06-01

Heat pump systems using treated sewage water as the heat source were used in the Beijing Olympic Village for domestic heating and cooling. However, considerable biofouling occurred in the plate heat exchangers used in the heat pump system, greatly limiting the system efficiency. This study investigates the biofouling characteristics using a plate heat exchanger in parallel with a flow cell system to focus on the effect of calcium ions on the biofilm development. The interactions between the microorganisms and Ca(2+) enhances both the extent and the rate of biofilm development with increasing Ca(2+) concentration, leading to increased heat transfer and flow resistances. Three stages of biofouling development were identified in the presence of Ca(2+) from different biofouling mass growth rates with an initial stage, a rapid growth stage and an extended growth stage. Each growth stage had different biofouling morphologies influenced by the Ca(2+) concentration. The effects of Ca(2+) on the biofouling heat transfer and flow resistances had a synergistic effect related to both the biofouling mass and the morphology. The effect of Ca(2+) on the biofouling development was most prominent during the rapid growth stage. Copyright © 2012 Elsevier B.V. All rights reserved.

Field comparison of optical and clark cell dissolved-oxygen sensors

USGS Publications Warehouse

Fulford, J.M.; Davies, W.J.; Garcia, L.

2005-01-01

Three multi-parameter water-quality monitors equipped with either Clark cell type or optical type dissolved-oxygen sensors were deployed for 30 days in a brackish (salinity <10 parts per thousand) environment to determine the sensitivity of the sensors to biofouling. The dissolved-oxygen sensors compared periodically to a hand-held dissolved oxygen sensor, but were not serviced or cleaned during the deployment. One of the Clark cell sensors and the optical sensor performed similarly during the deployment. The remaining Clark cell sensor was not aged correctly prior to deployment and did not perform as well as the other sensors. All sensors experienced substantial biofouling that gradually degraded the accuracy of the dissolved-oxygen measurement during the last half of the deployment period. Copyright ASCE 2005.

Quorum Quenching Mediated Approaches for Control of Membrane Biofouling

PubMed Central

Lade, Harshad; Paul, Diby; Kweon, Ji Hyang

2014-01-01

Membrane biofouling is widely acknowledged as the most frequent adverse event in wastewater treatment systems resulting in significant loss of treatment efficiency and economy. Different strategies including physical cleaning and use of antimicrobial chemicals or antibiotics have been tried for reducing membrane biofouling. Such traditional practices are aimed to eradicate biofilms or kill the bacteria involved, but the greater efficacy in membrane performance would be achieved by inhibiting biofouling without interfering with bacterial growth. As a result, the search for environmental friendly non-antibiotic antifouling strategies has received much greater attention among scientific community. The use of quorum quenching natural compounds and enzymes will be a potential approach for control of membrane biofouling. This approach has previously proven useful in diseases and membrane biofouling control by triggering the expression of desired phenotypes. In view of this, the present review is provided to give the updated information on quorum quenching compounds and elucidate the significance of quorum sensing inhibition in control of membrane biofouling. PMID:24910534

Spatial variation in biofouling of a unionid mussel (Lampsilis siliquoidea) across the western basin of Lake Erie

USGS Publications Warehouse

Larson, James H.; Evans, Mary; Richardson, William B.; Schaeffer, Jeff; Nelson, John

2016-01-01

Invasion of North American waters by nonnative Dreissena polymorpha and D. rostriformis bugensishas resulted in declines of the Unionidae family of native North American mussels. Dreissenid mussels biofoul unionid mussels in large numbers and interfere with unionid movement, their acquisition of food, and the native mussels' ability to open and close their shells. Initial expectations for the Great Lakes included extirpation of unionids where they co-occurred with dreissenids, but recently adult and juvenile unionids have been found alive in several apparent refugia. These unionid populations may persist due to reduced dreissenid biofouling in these areas, and/or due to processes that remove biofoulers. For example locations inaccessible to dreissenid veligers may reduce biofouling and habitats with soft substrates may allow unionids to burrow and thus remove dreissenids. We deployed caged unionid mussels (Lampsilis siliquoidea) at 36 sites across the western basin of Lake Erie to assess spatial variation in biofouling and to identify other areas that might promote the persistence or recovery of native unionid mussels. Biofouling ranged from 0.03 – 26.33 g per mussel, reached a maximum in the immediate vicinity of the mouth of the Maumee River, and appeared to primarily consist of dreissenid mussels. A known mussel refugium in the vicinity of a power plant near the mouth of the Maumee actually exhibited very high biofouling rates, suggesting that low dreissenid colonization did not adequately explain unionid survival in this refugium. In contrast, the southern nearshore area of Lake Erie, near another refugium, had very low biofouling. A large stretch of the western basin appeared to have low biofouling rates and muddy substrates, raising the possibility that these open water areas could support remnant and returning populations of unionid mussels. Previous observations of unionid refugia and the occurrence of low biofouling rates in large areas of the western basin of Lake Erie raise the possibility that unionid and dreissenid coexistence may be possible here and elsewhere.

Numerical study on the hydrodynamic characteristics of biofouled full-scale net cage

NASA Astrophysics Data System (ADS)

Bi, Chun-wei; Zhao, Yun-peng; Dong, Guo-hai

2015-06-01

The effect of biofouling on the hydrodynamic characteristics of the net cage is of particular interest as biofouled nettings can significantly reduce flow of well-oxygenated water reaching the stocked fish. For computational efficiency, the porous-media fluid model is proposed to simulate flow through the biofouled plane net and full-scale net cage. The porous coefficients of the porous-media fluid model can be determined from the quadratic-function relationship between the hydrodynamic forces on a plane net and the flow velocity using the least squares method. In this study, drag forces on and flow fields around five plane nets with different levels of biofouling are calculated by use of the proposed model. The numerical results are compared with the experimental data of Swift et al. (2006) and the effectiveness of the numerical model is presented. On that basis, flow through full-scale net cages with the same level of biofouling as the tested plane nets are modeled. The flow fields inside and around biofouled net cages are analyzed and the drag force acting on a net cage is estimated by a control volume analysis method. According to the numerical results, empirical formulas of reduction in flow velocity and load on a net cage are derived as function of drag coefficient of the corresponding biofouled netting.

Portable pilot plant for evaluating marine biofouling growth and control in heat exchangers-condensers.

PubMed

Casanueva, J F; Sánchez, J; García-Morales, J L; Casanueva-Robles, T; López, J A; Portela, J R; Nebot, E; Sales, D

2003-01-01

Biofouling frequently involves a serious impediment to achieving optimum operating conditions in heat exchangers-condensers. The economic coat and energy losses associated with this phenomenon are significant and the environmental impact of biocides must satisfy stringent regulations. A portable pilot plant has been designed in order to carry out in-situ experimental study as biofilm is formed under thermal and hydrodynamically controlled conditions. The pilot plant has an automatic monitoring, control and data acquisition system, which automatically processes data from indirect measure of fouling in terms of increased fluid frictional and heat transfer resistances. A particular method is used and proposed for direct measuring and biofilm characterization. Once we know the actual film thickness, we can calculate the effective thermal conductivity of the layer by using the appropriate heat transfer equations.

Anti-biofouling superhydrophobic surface fabricated by picosecond laser texturing of stainless steel

NASA Astrophysics Data System (ADS)

Sun, Ke; Yang, Huan; Xue, Wei; He, An; Zhu, Dehua; Liu, Wenwen; Adeyemi, Kenneth; Cao, Yu

2018-04-01

Anti-biofouling technology is based on specifically designed materials and coatings. This is an enduring goal in the maritime industries, such as shipping, offshore oil exploration, and aquaculture. Recently, research of the relationship between wettability and antifouling effectiveness has attracted considerable attention, due to the anti-biofouling properties of the lotus leaf and shark skin. In this study, super-hydrophobic surfaces (SHSs) with controllable periodic structures were fabricated on AISI304 stainless steel by a picosecond laser, and their anti-biofouling performance were investigated by seawater immersion for five weeks in summertime. The results showed that the specimens with SHS demonstrate significant anti-biofouling effect as compared with the bare stainless steel plate. We observed that nearly 50% decrease of the average microbe attachment area ratio (Avg. MAAR) could be obtained. The micro-groove SHS with more abundant hierarchical micro-nano structures showed better anti-biofouling performance than the micro-pit SHS.

Mini-review: Assessing the drivers of ship biofouling management--aligning industry and biosecurity goals.

PubMed

Davidson, Ian; Scianni, Christopher; Hewitt, Chad; Everett, Richard; Holm, Eric; Tamburri, Mario; Ruiz, Gregory

2016-01-01

Biofouling exerts a frictional and cost penalty on ships and is a direct cause of invasion by marine species. These negative consequences provide a unifying purpose for the maritime industry and biosecurity managers to prevent biofouling accumulation and transfer, but important gaps exist between these sectors. This mini-review examines the approach to assessments of ship biofouling among sectors (industry, biosecurity and marine science) and the implications for existing and emerging management of biofouling. The primary distinctions between industry and biosecurity in assessment of vessels biofouling revolve around the resolution of biological information collected and the specific wetted surface areas of primary concern to each sector. The morphological characteristics of biofouling and their effects on propulsion dynamics are of primary concern to industry, with an almost exclusive focus on the vertical sides and flat bottom of hulls and an emphasis on antifouling and operational performance. In contrast, the identity, biogeography, and ecology of translocated organisms is of highest concern to invasion researchers and biosecurity managers and policymakers, especially as it relates to species with known histories of invasion elsewhere. Current management practices often provide adequate, although not complete, provision for hull surfaces, but niche areas are well known to enhance biosecurity risk. As regulations to prevent invasions emerge in this arena, there is a growing opportunity for industry, biosecurity and academic stakeholders to collaborate and harmonize efforts to assess and manage biofouling of ships that should lead to more comprehensive biofouling solutions that promote industry goals while reducing biosecurity risk and greenhouse gas emissions.

Survival of ship biofouling assemblages during and after voyages to the Canadian Arctic.

PubMed

Chan, Farrah T; MacIsaac, Hugh J; Bailey, Sarah A

2016-01-01

Human-mediated vectors often inadvertently translocate species assemblages to new environments. Examining the dynamics of entrained species assemblages during transport can provide insights into the introduction risk associated with these vectors. Ship biofouling is a major transport vector of nonindigenous species in coastal ecosystems globally, yet its magnitude in the Arctic is poorly understood. To determine whether biofouling organisms on ships can survive passages in Arctic waters, we examined how biofouling assemblage structure changed before, during, and after eight round-trip military voyages from temperate to Arctic ports in Canada. Species richness first decreased (~70% loss) and then recovered (~27% loss compared to the original assemblages), as ships travelled to and from the Arctic, respectively, whereas total abundance typically declined over time (~55% total loss). Biofouling community structure differed significantly before and during Arctic transits as well as between those sampled during and after voyages. Assemblage structure varied across different parts of the hull; however, temporal changes were independent of hull location, suggesting that niche areas did not provide protection for biofouling organisms against adverse conditions in the Arctic. Biofouling algae appear to be more tolerant of transport conditions during Arctic voyages than are mobile, sessile, and sedentary invertebrates. Our results suggest that biofouling assemblages on ships generally have poor survivorship during Arctic voyages. Nonetheless, some potential for transporting nonindigenous species to the Arctic via ship biofouling remains, as at least six taxa new to the Canadian Arctic, including a nonindigenous cirripede, appeared to have survived transits from temperate to Arctic ports.

Recent Advances in the Study of Microbiologically Influenced Corrosion

DTIC Science & Technology

1993-01-01

Bacterial Behavior During Biofouling of Surfaces. Proceedings of Biofouling/ Biocorrosion in Water Systems (1992 Symposium American Chemical Society...Enhancement of Biocide Action for Improved Biofouling and Biocorrosion Con- trol. Proceedings of BiofoulinglBiocorrosion in Water Systems (1992 Symposium

Field Validation of POCIS for Monitoring at Underwater Munitions Sites.

PubMed

Rosen, Gunther; Lotufo, Guilherme R; George, Robert D; Wild, Bill; Rabalais, Lauren K; Morrison, Shane; Belden, Jason B

2018-04-24

The present study evaluated Polar Organic Chemical Integrative Samplers (POCIS) for quantification of conventional munitions constituents (MC), including trinitrotoluene (TNT), aminodinitrotoluenes, diaminonitrotoluenes, dinitrotoluene, and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in a field setting. POCIS were deployed at varying distances from the commonly used explosive formulation Composition B (39.5% TNT, 59.5% RDX, 1% wax) in an embayment of Santa Rosa Sound (Florida, USA). Time-weighted averaged (TWA) water concentrations from a 13-day deployment ranged from 9-103 ng/L for TNT and RDX approximately 0.3 to 2 m from the source. Concentrations decreased with increasing distance from the source to below quantitation limits (5-7 ng/L) at stations greater than 2 m away. Moderate biofouling of POCIS membranes after 13-d led to a subsequent effort to quantify potential effects of biofouling on sampling rate for MC. After biofouling was allowed to occur for periods of 0, 7, 14 or 28 days at the field site, POCIS were transferred to aquaria spiked with MC. No significant differences in uptake of TNT or RDX were observed across a gradient of biofouling presence, although mass of fouling organisms on the membranes was statistically greater for the 28-d field exposure. The present study verified the high sensitivity and integrative nature of POCIS for relevant MC potentially present in aquatic environments, indicating that application at underwater military munitions sites may be useful for ecological risk assessment. This article is protected by copyright. All rights reserved This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Control of membrane biofouling in MBR for wastewater treatment by quorum quenching bacteria encapsulated in microporous membrane.

PubMed

Oh, Hyun-Suk; Yeon, Kyung-Min; Yang, Cheon-Seok; Kim, Sang-Ryoung; Lee, Chung-Hak; Park, Son Young; Han, Jong Yun; Lee, Jung-Kee

2012-05-01

Recently, enzymatic quorum quenching has proven its potential as an innovative approach for biofouling control in the membrane bioreactor (MBR) for advanced wastewater treatment. However, practical issues on the cost and stability of enzymes are yet to be solved, which requires more effective quorum quenching methods. In this study, a novel quorum quenching strategy, interspecies quorum quenching by bacterial cell, was elaborated and proved to be efficient and economically feasible biofouling control in MBR. A recombinant Escherichia coli which producing N-acyl homoserine lactonase or quorum quenching Rhodococcus sp. isolated from a real MBR plant was encapsulated inside the lumen of microporous hollow fiber membrane, respectively. The porous membrane containing these functional bacteria (i.e., "microbial-vessel") was put into the submerged MBR to alleviate biofouling on the surface of filtration membrane. The effect of biofouling inhibition by the microbial-vessel was evaluated over 80 days of MBR operation. Successful control of biofouling in a laboratory scale MBR suggests that the biofouling control through the interspecies quorum quenching could be expanded to the plant scale of MBR and various environmental engineering systems with economic feasibility. © 2012 American Chemical Society

Biofouling of reverse-osmosis membranes during tertiary wastewater desalination: microbial community composition.

PubMed

Al Ashhab, Ashraf; Herzberg, Moshe; Gillor, Osnat

2014-03-01

Reverse-osmosis (RO) desalination is frequently used for the production of high-quality water from tertiary treated wastewater (TTWW). However, the RO desalination process is often hampered by biofouling, including membrane conditioning, microbial adhesion, and biofilm growth. The vast majority of biofilm exploration concentrated on the role of bacteria in biofouling neglecting additional microbial contributors, i.e., fungi and archaea. To better understand the RO biofouling process, bacterial, archaeal and fungal diversity was characterized in a laboratory-scale RO desalination plant exploring the TTWW (RO feed), the RO membrane and the RO feed tube biofilms. We sequenced 77,400 fragments of the ribosome small subunit-encoding gene (16S and 18S rRNA) to identify the microbial community members in these matrices. Our results suggest that the bacterial, archaeal but not fungal community significantly differ from the RO membrane biofouling layer to the feedwater and tube biofilm (P < 0.01). Moreover, the RO membrane supported a more diverse community compared to the communities monitored in the feedwater and the biofilm attached to the RO feedwater tube. The tube biofilm was dominated by Actinobacteria (91.2 ± 4.6%), while the Proteobacteria phylum dominated the feedwater and RO membrane (at relative abundance of 92.3 ± 4.4% and 71.5 ± 8.3%, respectively), albeit comprising different members. The archaea communities were dominated by Crenarchaeota (53.0 ± 6.9%, 32.5 ± 7.2% and 69%, respectively) and Euryarchaeota (43.3 ± 6.3%, 23.2 ± 4.8% and 24%, respectively) in all three matrices, though the communities' composition differed. But the fungal communities composition was similar in all matrices, dominated by Ascomycota (97.6 ± 2.7%). Our results suggest that the RO membrane is a selective surface, supporting unique bacterial, and to a lesser extent archaeal communities, yet it does not select for a fungal community. Copyright © 2013 Elsevier Ltd. All rights reserved.

Vanadium pentoxide nanoparticles mimic vanadium haloperoxidases and thwart biofilm formation

NASA Astrophysics Data System (ADS)

Natalio, Filipe; André, Rute; Hartog, Aloysius F.; Stoll, Brigitte; Jochum, Klaus Peter; Wever, Ron; Tremel, Wolfgang

2012-08-01

Marine biofouling--the colonization of small marine microorganisms on surfaces that are directly exposed to seawater, such as ships' hulls--is an expensive problem that is currently without an environmentally compatible solution. Biofouling leads to increased hydrodynamic drag, which, in turn, causes increased fuel consumption and greenhouse gas emissions. Tributyltin-free antifouling coatings and paints based on metal complexes or biocides have been shown to efficiently prevent marine biofouling. However, these materials can damage the environment through metal leaching (for example, of copper and zinc) and bacteria resistance. Here, we show that vanadium pentoxide nanowires act like naturally occurring vanadium haloperoxidases to prevent marine biofouling. In the presence of bromide ions and hydrogen peroxide, the nanowires catalyse the oxidation of bromide ions to hypobromous acid (HOBr). Singlet molecular oxygen (1O2) is formed and this exerts strong antibacterial activity, which prevents marine biofouling without being toxic to marine biota. Vanadium pentoxide nanowires have the potential to be an alternative approach to conventional anti-biofouling agents.

Uncertainty analysis routine for the Ocean Thermal Energy Conversion (OTEC) biofouling measurement device and data reduction procedure. [HTCOEF code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bird, S.P.

1978-03-01

Biofouling and corrosion of heat exchanger surfaces in Ocean Thermal Energy Conversion (OTEC) systems may be controlling factors in the potential success of the OTEC concept. Very little is known about the nature and behavior of marine fouling films at sites potentially suitable for OTEC power plants. To facilitate the acquisition of needed data, a biofouling measurement device developed by Professor J. G. Fetkovich and his associates at Carnegie-Mellon University (CMU) has been mass produced for use by several organizations in experiments at a variety of ocean sites. The CMU device is designed to detect small changes in thermal resistancemore » associated with the formation of marine microfouling films. An account of the work performed at the Pacific Northwest Laboratory (PNL) to develop a computerized uncertainty analysis for estimating experimental uncertainties of results obtained with the CMU biofouling measurement device and data reduction scheme is presented. The analysis program was written as a subroutine to the CMU data reduction code and provides an alternative to the CMU procedure for estimating experimental errors. The PNL code was used to analyze sample data sets taken at Keahole Point, Hawaii; St. Croix, the Virgin Islands; and at a site in the Gulf of Mexico. The uncertainties of the experimental results were found to vary considerably with the conditions under which the data were taken. For example, uncertainties of fouling factors (where fouling factor is defined as the thermal resistance of the biofouling layer) estimated from data taken on a submerged buoy at Keahole Point, Hawaii were found to be consistently within 0.00006 hr-ft/sup 2/-/sup 0/F/Btu, while corresponding values for data taken on a tugboat in the Gulf of Mexico ranged up to 0.0010 hr-ft/sup 2/-/sup 0/F/Btu. Reasons for these differences are discussed.« less

The Antifouling of ACLW-CAR Based on Ultrasonic Cleaner

NASA Astrophysics Data System (ADS)

Zhang, Guohua; Liu, Shixuan; Qin, Qingliang

2017-10-01

Equipped with ACLW-CAR, the buoy provided effective technical platform for on-site rapid monitoring of the chlorophyll and turbidity. Performance index and usage in the ocean buoy of ACLW-CAR was introduced. Ultrasonic cleaning method in seawater was developed for preventing ACLW-CAR from biofouling. Marine chlorophyll and turbidity data can serve for oceanographic research and marine resource exploitation.

FEASIBILITY OF ULTRASONIC AND OTHER METHODS FOR DIRECT MEASUREMENT OF CONDENSER BIOFOULING

EPA Science Inventory

The report gives results of a literature review and laboratory studies of the potential of ultrasonic and other methods for in-situ measurement of biofouling on heat transfer surfaces (e.g., tubes) of electric utility steam condensers. Detection of the presence of biofouling in s...

Evaluation of Glider Coatings against Biofouling for Improved Flight Performance

DTIC Science & Technology

2010-09-30

the different stages of settlement, attachment and fouling release to be studied in detail. This is especially important, as the key to antifouling (ie... antifouling coatings. Biofouling 10: 187-197. Swain, G.W. et al. (2000) Biofouling and barnacle adhesion data for fouling-release coatings subjected

Evaluation of biofouling in stainless microfluidic channels for implantable multilayered dialysis device

NASA Astrophysics Data System (ADS)

Ota, Takashi; To, Naoya; Kanno, Yoshihiko; Miki, Norihisa

2017-06-01

An implantable artificial kidney can markedly improve the quality of life of renal disease patients. Our group has developed an implantable multilayered dialysis system consisting of microfluidic channels and dialysis membranes. Long-term evaluation is necessary for implant devices where biofouling is a critical factor, culminating in the deterioration of dialysis performance. Our previous work revealed that surface conditions, which depend on the manufacturing process, determine the amount of biofouling, and that electrolytic etching is the most suitable technique for forming a channel wall free of biofouling. In this study, we investigated the electrolytic etching conditions in detail. We conducted in vitro experiments for 7 d and evaluated the adhesion of biomaterials by scanning electron microscopy. The experiments revealed that a surface mirror-finished by electrolytic etching effectively prevents biofouling.

Biofouling development on plasma treated samples versus layers coated samples

NASA Astrophysics Data System (ADS)

Hnatiuc, B.; Exnar, P.; Sabau, A.; Spatenka, P.; Dumitrache, C. L.; Hnatiuc, M.; Ghita, S.

2016-12-01

Biofouling is the most important cause of naval corrosion. In order to reduce the Biofouling development on naval materials as steel or resin, different new methods have been tested. These methods could help to follow the new IMO environment reglementations and they could replace few classic operations before the painting of the small ships. The replacement of these operations means a reduction in maintenance costs. Their action must influence especially the first two steps of the Biofouling development, called Microfouling, that demand about 24 hours. This work presents the comparative results of the Biofouling development on two different classic naval materials, steel and resin, for three treated samples, immersed in sea water. Non-thermal plasma, produced by GlidArc technology, is applied to the first sample, called GD. The plasma treatment was set to 10 minutes. The last two samples, called AE9 and AE10 are covered by hydrophobic layers, prepared from a special organic-inorganic sol synthesized by sol-gel method. Theoretically, because of the hydrophobic properties, the Biofouling formation must be delayed for AE9 and AE10. The Biofouling development on each treated sample was compared with a witness non-treated sample. The microbiological analyses have been done for 24 hours by epifluorescence microscopy, available for one single layer.

Biosecurity Management of Submarine Niche Areas: the Effect of Water Pressure on Biofouling Survival

DTIC Science & Technology

2014-01-01

UNCLASSIFIED UNCLASSIFIED Biosecurity Management of Submarine Niche Areas: the Effect of Water Pressure on Biofouling Survival Clare...operational impacts and biosecurity risks. Approved for public release RELEASE LIMITATION UNCLASSIFIED...UNCLASSIFIED UNCLASSIFIED Biosecurity Management of Submarine Niche Areas: the Effect of Water Pressure on Biofouling Survival Executive Summary

Mechanisms and methods for biofouling prevention via aeration

NASA Astrophysics Data System (ADS)

Dickenson, Natasha; Henoch, Charles; Belden, Jesse

2013-11-01

Biofouling is a major problem for the Navy and marine industries, with significant economic and ecological consequences. Specifically, biofouling on immersed hull surfaces generates increased drag and thus requires increased fuel consumption to maintain speed. Considerable effort has been spent developing techniques to prevent and control biofouling, but with limited success. Control methods that have proven to be effective are costly, time consuming, or negatively affect the environment. Recently, aeration via bubble injection along submerged surfaces has been shown to achieve long-lasting antifouling effects, and is the only effective non-toxic method available. An understanding of the basic mechanisms by which bubble-induced flow impedes biofouling is lacking, but is essential for the design of large-scale systems. We present results from an experimental investigation of several bubble induced flow fields over an inclined plate with simultaneous measurements of the fluid velocity and bubble characteristics using Digital article Image Velocimetry and high speed digital video. Trajectories of representative larval organisms are also resolved and linked with the flow field measurements to determine the mechanisms responsible for biofouling prevention.

Linking ceragenins to water-treatment membranes to minimize biofouling.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hibbs, Michael R.; Altman, Susan Jeanne; Feng, Yanshu

Ceragenins were used to create biofouling resistant water-treatment membranes. Ceragenins are synthetically produced antimicrobial peptide mimics that display broad-spectrum bactericidal activity. While ceragenins have been used on bio-medical devices, use of ceragenins on water-treatment membranes is novel. Biofouling impacts membrane separation processes for many industrial applications such as desalination, waste-water treatment, oil and gas extraction, and power generation. Biofouling results in a loss of permeate flux and increase in energy use. Creation of biofouling resistant membranes will assist in creation of clean water with lower energy usage and energy with lower water usage. Five methods of attaching three different cerageninmore » molecules were conducted and tested. Biofouling reduction was observed in the majority of the tests, indicating the ceragenins are a viable solution to biofouling on water treatment membranes. Silane direct attachment appears to be the most promising attachment method if a high concentration of CSA-121a is used. Additional refinement of the attachment methods are needed in order to achieve our goal of several log-reduction in biofilm cell density without impacting the membrane flux. Concurrently, biofilm forming bacteria were isolated from source waters relevant for water treatment: wastewater, agricultural drainage, river water, seawater, and brackish groundwater. These isolates can be used for future testing of methods to control biofouling. Once isolated, the ability of the isolates to grow biofilms was tested with high-throughput multiwell methods. Based on these tests, the following species were selected for further testing in tube reactors and CDC reactors: Pseudomonas ssp. (wastewater, agricultural drainage, and Colorado River water), Nocardia coeliaca or Rhodococcus spp. (wastewater), Pseudomonas fluorescens and Hydrogenophaga palleronii (agricultural drainage), Sulfitobacter donghicola, Rhodococcus fascians, Rhodobacter katedanii, and Paracoccus marcusii (seawater), and Sphingopyxis spp. (groundwater). The testing demonstrated the ability of these isolates to be used for biofouling control testing under laboratory conditions. Biofilm forming bacteria were obtained from all the source water samples.« less

An Investigation of Low Biofouling Copper-charged Membranes

NASA Astrophysics Data System (ADS)

Asapu, Sunitha

Water is essential for the survival of life on Earth, but pollutants in water can cause dangerous diseases and fatalities. The need for purified water has been increasing with increasing world population; however, natural sources of water such as rivers, lakes and streams, are progressively falling shorter and shorter of meeting water needs. The provision of clean, drinkable water to people is a key factor for the development of novel and alternative water purification technologies, such as membrane separations. Nanofiltration (NF) is a membrane separations technology that purifies water from lower quality sources, such as brackish water, seawater and wastewater. During the filtration of such sources, materials that are rejected by the membrane may accumulate on the surface of the membrane to foul it. Such materials include organic and inorganic matter, colloids, salts and microorganisms. The former four can often be controlled via pretreatment; however, the accumulation of microorganisms is more problematic to membranes. Biofouling is the accumulation and growth of microorganisms on the surface of membranes and on feed spacers. After attachment, microorganisms excrete extracellular polymeric substances (EPS), which form a matrix around the organism's outer surface as biofilm. These biofilms are detrimental and result in irreversible membrane fouling. Copper and silver ions inactivate the bacterial cells and prevent the DNA replication in microbial cells. Previous studies using copper-charged feed spacers have shown the ability of copper to control biofouling without a significant amount of copper leaching from copper-charged polypropylene (PP) feed spacers during crossflow filtration. Also, filtration using unmodified speed facers experienced almost 70% flux decline, while filtration using copper-charged feed spacers displayed only 25% flux decline. These intriguing results led to the hypothesis that the polymer chemistry could be extrapolated to produce membranes with increased biofouling resistance. The goal of this project was to develop low-biofouling nanofiltration cellulose acetate (CA) membranes through functionalization with metal chelating ligands charged with biocidal metal ions, i.e. copper ions. To this end, glycidyl methacrylate (GMA), an epoxy, was used to attach a chelating agent, iminodiacetic acid (IDA) to facilitate the charging of copper to the membrane surface. Both CA and CA-GMA membranes were cast using the phase-inversion method. The CA-GMA membranes were then charged with copper ions to make them low biofouling. Pore size distribution analysis of CA and copper charged membranes were conducted using various molecular weights of polyethylene glycol (PEG). CA and copper-charged membranes were characterized using Fourier Transform Infrared (FTIR), contact angle to measure hydrophilicity changes, and using scanning electron microscope (SEM) coupled with X-ray energy dispersive spectroscopy EDS to monitor copper leaching. Permeation experiments were conducted with distilled (DI) water, protein solutions, and synthetic brackish water containing microorganisms. The DI water permeation of the copper-charged membranes was initially lower than the CA membranes. The membranes were then subjected to bovine serum albumin (BSA) and lipase filtration. The copper-charged membranes showed higher pure water flux values for both proteins as compared to CA membranes. The rejection of BSA and lipase was the same for both the copper charged and CA membranes. The filtration with the synthetic brackish water showed that copper-charged membranes had higher flux values as compared to CA membranes, and biofouling analysis showed more bacteria on the CA membranes as compared to copper-charged membranes. Therefore, the copper-charged membranes made here have shown a potential to be used as low-biofouling membranes in the future.

Biofouling community composition across a range of environmental conditions and geographical locations suitable for floating marine renewable energy generation.

PubMed

Macleod, Adrian K; Stanley, Michele S; Day, John G; Cook, Elizabeth J

2016-01-01

Knowledge of biofouling typical of marine structures is essential for engineers to define appropriate loading criteria in addition to informing other stakeholders about the ecological implications of creating novel artificial environments. There is a lack of information regarding biofouling community composition (including weight and density characteristics) on floating structures associated with future marine renewable energy generation technologies. A network of navigation buoys were identified across a range of geographical areas, environmental conditions (tidal flow speed, temperature and salinity), and deployment durations suitable for future developments. Despite the perceived importance of environmental and temporal factors, geographical location explained the greatest proportion of the observed variation in community composition, emphasising the importance of considering geography when assessing the impact of biofouling on device functioning and associated ecology. The principal taxa associated with variation in biofouling community composition were mussels (Mytilus edulis), which were also important when determining loading criteria.

The effect of vessel speed on the survivorship of biofouling organisms at different hull locations.

PubMed

Coutts, Ashley D M; Piola, Richard F; Taylor, Michael D; Hewitt, Chad L; Gardner, Jonathan P A

2010-07-01

This study used a specially designed MAGPLATE system to quantify the en route survivorship and post-voyage recovery of biofouling assemblages subjected to short voyages (< 12 h) across a range of vessel speeds (slow, medium, fast; in the range 4.0-21.5 knots). The effect of hull location (bow, amidships and stern) was also examined. While no significant differences were evident in en route survivorship of biofouling organisms amongst hull locations, biofouling cover and richness were markedly reduced on faster vessels relative to slower craft. Therefore, the potential inoculum size of non-indigenous marine species and richness is likely to be reduced for vessels that travel at faster speeds (> 14 knots), which is likely to also reduce the chances of successful introductions. Despite this, the magnitude of introductions from biofouling on fast vessels can be considered minor, especially for species richness where 90% of source-port species were recorded at destinations.

Characterisation of the biofouling community on a floating wave energy device.

PubMed

Nall, Christopher R; Schläppy, Marie-Lise; Guerin, Andrew J

2017-05-01

Wave energy devices are novel structures in the marine environment and, as such, provide a unique habitat for biofouling organisms. In this study, destructive scrape samples and photoquadrats were used to characterise the temperate epibenthic community present on prototypes of the Pelamis wave energy converter. The biofouling observed was extensive and diverse with 115 taxa recorded including four non-native species. Vertical zonation was identified on the sides of the device, with an algae-dominated shallow subtidal area and a deeper area characterised by a high proportion of suspension-feeding invertebrates. Differences in species composition and biomass were also observed between devices, along the length of the device and between sampling dates. This research provides an insight into the variation of biofouling assemblages on a wave energy device as well as the potential technical and ecological implications associated with biofouling on marine renewable energy structures.

Air bubbles induce a critical continuous stress to prevent marine biofouling accumulation

NASA Astrophysics Data System (ADS)

Belden, Jesse; Menesses, Mark; Dickenson, Natasha; Bird, James

2017-11-01

Significant shear stresses are needed to remove established hard fouling organisms from a ship hull. Given that there is a link between the amount of time that fouling accumulates and the stress required to remove it, it is not surprising that more frequent grooming requires less shear stress. One approach to mitigate marine biofouling is to continuously introduce a curtain of air bubbles under a submerged surface; it is believed that this aeration exploits the small stresses induced by rising bubbles to continuously prevent accumulation. Although curtains of rising bubbles have successfully prevented biofouling accumulation, it is unclear if a single stream of bubbles could maintain a clean surface. In this talk, we show that single bubble stream aeration can prevent biofouling accumulation in regions for which the average wall stress exceeds approximately 0.01 Pa. This value is arrived at by comparing observations of biofouling growth and prevention from field studies with laboratory measurements that probe the associated flow fields. We also relate the spatial and temporal characteristics of the flow to the size and frequency of the rising bubbles, which informs the basic operating conditions required for aeration to continuously prevent biofouling accumulation.

Monitoring and toxicity evaluation of phytoplankton on lithium manganese oxide adsorbents at lithium recovery pilot plant field.

NASA Astrophysics Data System (ADS)

Yoon, H. O.; Kim, J. A.; Kim, J. C.; Chung, K. S.; Ryu, J. H.

2015-12-01

For recovery of rare mineral resources such as lithium or boron from seawater, the lithium adsorbent material have been made by Korea Institute of Geoscience and Mineral Resources (KIGAM) and pilot plant was conducted in Okgye Harbor, Gangneung, Korea. The application of lithium adsorbent in pilot plant, it is important to consider the impact on the marine environment. Especially phytoplankton communities are important marine microorganism to represent marine primary product. At the same time, phytoplankton is possible to induce the decrease of lithium recovery rate due to cause of biofouling to surfaces of lithium adsorbents. Therefore long-term and periodic monitoring of phytoplankton is necessary to understand the environmental impact and biofouling problems near the lithium pilot plant. The abundance and biomass of phytoplankton have been evaluated through monthly interval sampling from February 2013 to May 2015. Abundance and species diversity of phytoplankton went up to summer from winter. When lithium adsorbents were immersing to seawater, eco-toxicities of released substances were determined using Microtox with bioluminescence bacteria Vibrio fischeri. The adsorbents were soaked in sterilized seawater and aeration for 1, 3, 5, 7, 10 and 14 days intervals under controlled temperature. Maximum EC50 concentration was 61.4% and this toxicity was showed in more than 10 days exposure.

Analysis of micromixers and biocidal coatings on water-treatment membranes to minimize biofouling.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Webb, Stephen W.; James, Darryl L.; Hibbs, Michael R.

2009-12-01

Biofouling, the unwanted growth of biofilms on a surface, of water-treatment membranes negatively impacts in desalination and water treatment. With biofouling there is a decrease in permeate production, degradation of permeate water quality, and an increase in energy expenditure due to increased cross-flow pressure needed. To date, a universal successful and cost-effect method for controlling biofouling has not been implemented. The overall goal of the work described in this report was to use high-performance computing to direct polymer, material, and biological research to create the next generation of water-treatment membranes. Both physical (micromixers - UV-curable epoxy traces printed on themore » surface of a water-treatment membrane that promote chaotic mixing) and chemical (quaternary ammonium groups) modifications of the membranes for the purpose of increasing resistance to biofouling were evaluated. Creation of low-cost, efficient water-treatment membranes helps assure the availability of fresh water for human use, a growing need in both the U. S. and the world.« less

N-Acyl Homoserine Lactone-Mediated Quorum Sensing with Special Reference to Use of Quorum Quenching Bacteria in Membrane Biofouling Control

PubMed Central

Paul, Diby

2014-01-01

Membrane biofouling remains a severe problem to be addressed in wastewater treatment systems affecting reactor performance and economy. The finding that many wastewater bacteria rely on N-acyl homoserine lactone-mediated quorum sensing to synchronize their activities essential for biofilm formations; the quenching bacterial quorum sensing suggests a promising approach for control of membrane biofouling. A variety of quorum quenching compounds of both synthetic and natural origin have been identified and found effective in inhibition of membrane biofouling with much less environmental impact than traditional antimicrobials. Work over the past few years has demonstrated that enzymatic quorum quenching mechanisms are widely conserved in several prokaryotic organisms and can be utilized as a potent tool for inhibition of membrane biofouling. Such naturally occurring bacterial quorum quenching mechanisms also play important roles in microbe-microbe interactions and have been used to develop sustainable nonantibiotic antifouling strategies. Advances in membrane fabrication and bacteria entrapment techniques have allowed the implication of such quorum quenching bacteria for better design of membrane bioreactor with improved antibiofouling efficacies. In view of this, the present paper is designed to review and discuss the recent developments in control of membrane biofouling with special emphasis on quorum quenching bacteria that are applied in membrane bioreactors. PMID:25147787

Hydrogel-coated feed spacers in two-phase flow cleaning in spiral wound membrane elements: a novel platform for eco-friendly biofouling mitigation.

PubMed

Wibisono, Yusuf; Yandi, Wetra; Golabi, Mohsen; Nugraha, Roni; Cornelissen, Emile R; Kemperman, Antoine J B; Ederth, Thomas; Nijmeijer, Kitty

2015-03-15

Biofouling is still a major challenge in the application of nanofiltration and reverse osmosis membranes. Here we present a platform approach for environmentally friendly biofouling control using a combination of a hydrogel-coated feed spacer and two-phase flow cleaning. Neutral (polyHEMA-co-PEG10MA), cationic (polyDMAEMA) and anionic (polySPMA) hydrogels have been successfully grafted onto polypropylene (PP) feed spacers via plasma-mediated UV-polymerization. These coatings maintained their chemical stability after 7 days incubation in neutral (pH 7), acidic (pH 5) and basic (pH 9) environments. Anti-biofouling properties of these coatings were evaluated by Escherichia coli attachment assay and nanofiltration experiments at a TMP of 600 kPag using tap water with additional nutrients as feed and by using optical coherence tomography. Especially the anionic polySPMA-coated PP feed spacer shows reduced attachment of E. coli and biofouling in the spacer-filled narrow channels resulting in delayed biofilm growth. Employing this highly hydrophilic coating during removal of biofouling by two-phase flow cleaning also showed enhanced cleaning efficiency, feed channel pressure drop and flux recoveries. The strong hydrophilic nature and the presence of negative charge on polySPMA are most probably responsible for the improved antifouling behavior. A combination of polySPMA-coated PP feed spacers and two-phase flow cleaning therefore is promising and an environmentally friendly approach to control biofouling in NF/RO systems employing spiral-wound membrane modules. Copyright © 2015 Elsevier Ltd. All rights reserved.

Preliminary Investigations of Biofouling of Ships’ Hulls: Non-Indigenous Species Investigations in the Columbia River

DTIC Science & Technology

2006-04-01

Oregon P Primary S Secondary SD Standard Deviation SE Standard Error TBT Tributyltin U.S. United States WA Washington WHOI Woods Hole...reasons hull biofouling was considered less important as a vector of organisms than ballast water (Carlton, 1985). In the early 1970s, tributyltin ... TBT ) became the dominant antifouling paint applied to 9 vessels because it was hugely successful in preventing biofouling accumulation

Predicting Glucose Sensor Behavior in Blood Using Transport Modeling: Relative Impacts of Protein Biofouling and Cellular Metabolic Effects

PubMed Central

Novak, Matthew T.; Yuan, Fan; Reichert, William M.

2013-01-01

Background Tissue response to indwelling glucose sensors remains a confounding barrier to clinical application. While the effects of fully formed capsular tissue on sensor response have been studied, little has been done to understand how tissue interactions occurring before capsule formation hinder sensor performance. Upon insertion in subcutaneous tissue, the sensor is initially exposed to blood, blood borne constituents, and interstitial fluid. Using human whole blood as a simple ex vivo experimental system, the effects of protein accumulation at the sensor surface (biofouling effects) and cellular consumption of glucose in both the biofouling layer and in the bulk (metabolic effects) on sensor response were assessed. Methods Medtronic MiniMed SofSensor glucose sensors were incubated in whole blood, plasma-diluted whole blood, and cell-free platelet-poor plasma (PPP) to analyze the impact of different blood constituents on sensor function. Experimental conditions were then simulated using MATLAB to predict the relative impacts of biofouling and metabolic effects on the observed sensor responses. Results Protein biofouling in PPP in both the experiments and the simulations was found to have no interfering effect upon sensor response. Experimental results obtained with whole and dilute blood showed that the sensor response was markedly affected by blood borne glucose-consuming cells accumulated in the biofouling layer and in the surrounding bulk. Conclusions The physical barrier to glucose transport presented by protein biofouling does not hinder glucose movement to the sensor surface, and the consumption of glucose by inflammatory cells, and not erythrocytes, proximal to the sensor surface has a substantial effect on sensor response and may be the main culprit for anomalous sensor behavior immediately following implantation. PMID:24351181

Microbial Studies of Biofouling of Treated and Untreated Wood Pilings in the Marine Environment.

DTIC Science & Technology

1986-02-28

into tropical marine waters. After that, little or no slowing of biofouling can be detected. The wood boring invertebrate , Limnoria, appears to develop a...Malins. 1977. Toxicity and metabolism of naph- thalene: a study with marine larval invertebrates . Proc. Soc. Exptl. Biol. Med. 154: 151. de Serres...of Biofouling of Treated FINAL REPORT ".- L and Untreated Wood Pilings in the ORG.RPORT.UMBEco Marine Environment . PoRMG O...: * I. AUTMOR(6) G

Quorum quenching bacteria can be used to inhibit the biofouling of reverse osmosis membranes.

PubMed

Oh, Hyun-Suk; Tan, Chuan Hao; Low, Jiun Hui; Rzechowicz, Miles; Siddiqui, Muhammad Faisal; Winters, Harvey; Kjelleberg, Staffan; Fane, Anthony G; Rice, Scott A

2017-04-01

Over the last few decades, significant efforts have concentrated on mitigating biofouling in reverse osmosis (RO) systems, with a focus on non-toxic and sustainable strategies. Here, we explored the potential of applying quorum quenching (QQ) bacteria to control biofouling in a laboratory-scale RO system. For these experiments, Pantoea stewartii was used as a model biofilm forming organism because it was previously shown to be a relevant wastewater isolate that also forms biofilms in a quorum sensing (QS) dependent fashion. A recombinant Escherichia coli strain, which can produce a QQ enzyme, was first tested in batch biofilm assays and significantly reduced biofilm formation by P. stewartii. Subsequently, RO membranes were fouled with P. stewartii and the QQ bacterium was introduced into the RO system using two different strategies, direct injection and immobilization within a cartridge microfilter. When the QQ bacterial cells were directly injected into the system, N-acylhomoserine lactone signals were degraded, resulting in the reduction of biofouling. Similarly, the QQ bacteria controlled biofouling when immobilized within a microfilter placed downstream of the RO module to remove QS signals circulating in the system. These results demonstrate the proof-of-principle that QQ can be applied to control biofouling of RO membranes and may be applicable for use in full-scale plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessing the port to port risk of vessel movements vectoring non-indigenous marine species within and across domestic Australian borders.

PubMed

Campbell, Marnie L; Hewitt, Chad L

2011-07-01

Biofouling of vessels is implicated as a high risk transfer mechanism of non-indigenous marine species (NIMS). Biofouling on international vessels is managed through stringent border control policies, however, domestic biofouling transfers are managed under different policies and legislative arrangements as they cross internal borders. As comprehensive guidelines are developed and increased compliance of international vessels with 'clean hull' expectations increase, vessel movements from port to port will become the focus of biosecurity management. A semi-quantitative port to port biofouling risk assessment is presented that evaluates the presence of known NIMS in the source port and determines the likelihood of transfer based on the NIMS association with biofouling and environmental match between source and receiving ports. This risk assessment method was used to assess the risk profile of a single dredge vessel during three anticipated voyages within Australia, resulting in negligible to low risk outcomes. This finding is contrasted with expectations in the literature, specifically those that suggest slow moving vessels pose a high to extreme risk of transferring NIMS species.

Effect of biofouling on the performance of amidoxime-based polymeric uranium adsorbents

DOE PAGES

Park, Jiyeon; Gill, Gary A.; Strivens, Jonathan E.; ...

2016-01-27

Here, the Marine Science Laboratory at the Pacific Northwest National Laboratory evaluated the impact of biofouling on uranium adsorbent performance. A surface modified polyethylene adsorbent fiber provided by Oak Ridge National Laboratory, AF adsorbent, was tested either in the presence or absence of light to simulate deployment in shallow or deep marine environments. 42-day exposure tests in column and flume settings showed decreased uranium uptake by biofouling. Uranium uptake was reduced by up to 30 %, in the presence of simulated sunlight, which also increased biomass accumulation and altered the microbial community composition on the fibers. These results suggest thatmore » deployment below the photic zone would mitigate the effects of biofouling, resulting in greater yields of uranium extracted from seawater.« less

Do biological-based strategies hold promise to biofouling control in MBRs?

PubMed

Malaeb, Lilian; Le-Clech, Pierre; Vrouwenvelder, Johannes S; Ayoub, George M; Saikaly, Pascal E

2013-10-01

Biofouling in membrane bioreactors (MBRs) remains a primary challenge for their wider application, despite the growing acceptance of MBRs worldwide. Research studies on membrane fouling are extensive in the literature, with more than 200 publications on MBR fouling in the last 3 years; yet, improvements in practice on biofouling control and management have been remarkably slow. Commonly applied cleaning methods are only partially effective and membrane replacement often becomes frequent. The reason for the slow advancement in successful control of biofouling is largely attributed to the complex interactions of involved biological compounds and the lack of representative-for-practice experimental approaches to evaluate potential effective control strategies. Biofouling is driven by microorganisms and their associated extra-cellular polymeric substances (EPS) and microbial products. Microorganisms and their products convene together to form matrices that are commonly treated as a black box in conventional control approaches. Biological-based antifouling strategies seem to be a promising constituent of an effective integrated control approach since they target the essence of biofouling problems. However, biological-based strategies are in their developmental phase and several questions should be addressed to set a roadmap for translating existing and new information into sustainable and effective control techniques. This paper investigates membrane biofouling in MBRs from the microbiological perspective to evaluate the potential of biological-based strategies in offering viable control alternatives. Limitations of available control methods highlight the importance of an integrated anti-fouling approach including biological strategies. Successful development of these strategies requires detailed characterization of microorganisms and EPS through the proper selection of analytical tools and assembly of results. Existing microbiological/EPS studies reveal a number of implications as well as knowledge gaps, warranting future targeted research. Systematic and representative microbiological studies, complementary utilization of molecular and biofilm characterization tools, standardized experimental methods and validation of successful biological-based antifouling strategies for MBR applications are needed. Specifically, in addition, linking these studies to relevant operational conditions in MBRs is an essential step to ultimately develop a better understanding and more effective and directed control strategy for biofouling. Copyright © 2013 Elsevier Ltd. All rights reserved.

Biofouling of groundwater systems by Thiothrix spp.

PubMed

Brigmon, R L; Martin, H W; Aldrich, H C

1997-09-01

Thiothrix spp., sulfide-oxidizing filamentous bacteria, were found to be a principal bacterial component of aquatic biofilms causing biofouling in selected municipal water storage tanks, private wells, and drip irrigation systems in Florida. Treatments of up to 200 ppm chlorine in the affected systems could not prevent return of the biofouling problem. The water originated from the upper Floridan aquifer and associated surficial aquifers in central and north Florida. Samples were examined where visible biofilms had a white, filamentous appearance, indicative of Thiothrix spp. The detection of Thiothrix spp. was confirmed by enzyme-liked immunosorbent assay (ELISA), indirect immunofluorescence (IIF), and microbiological procedures. It was estimated through immunocytochemical procedures that Thiothrix spp. comprised 18% of the biofilm in the municipal water storage tanks. These observations confirm that specific biological and chemical interactions may induce physical changes leading to significant biofouling.

Effect of anti-biofouling potential of multi-walled carbon nanotubes-filled polydimethylsiloxane composites on pioneer microbial colonization.

PubMed

Sun, Yuan; Lang, Yanhe; Sun, Qian; Liang, Shuang; Liu, Yongkang; Zhang, Zhizhou

2016-09-01

In this paper, two carbon nanotube (CNT) nanofillers, namely the multi-walled carbon nanotubes (MWCNTs) and the carboxyl-modified MWCNTs (cMWCNTs), were introduced into the polydimethylsiloxane (PDMS) matrix respectively, in order to produce the PDMS composites with reinforced anti-biofouling properties. The anti-biofouling capacity of the silicone-based coatings, including the unfilled PDMS (P0), the MWCNTs-filled PDMS (PM) and the cMWCNTs-filled PDMS (PC), was examined via the field assays conducted in Weihai, China. The effect of different silicone-based coatings on the dynamic variations of the pioneer microbial-community diversity was analyzed using the single-strand conformation polymorphism (SSCP) technique. The PM and PC surfaces have exhibited excellent anti-biofouling properties in contrast to that of the PDMS surface, with extremely low attachment of the early colonizers, such as juvenile invertebrates, seaweeds and algae sporelings. The PM and PC surfaces can effectively prevent biofouling for more than 12 weeks. These combined results suggest that the incorporation of MWCNTs or cMWCNTs into the PDMS matrix can dramatically reinforce its anti-biofouling properties. The SSCP analysis reveals that compared with the PDMS surfaces, the PM and PC surfaces have strong modulating effect on the pioneer prokaryotic and eukaryotic communities, particularly on the colonization of pioneer eukaryotic microbes. The significantly reduced pioneer eukaryotic-community diversity may contribute to the weakening of the subsequent colonization of macrofoulers. Copyright © 2016 Elsevier B.V. All rights reserved.

Anti-biofouling function of amorphous nano-Ta2O5 coating for VO2-based intelligent windows.

PubMed

Li, Jinhua; Guo, Geyong; Wang, Jiaxing; Zhou, Huaijuan; Shen, Hao; Yeung, Kelvin W K

2017-04-28

From environmental and health perspectives, the acquisition of a surface anti-biofouling property holds important significance for the usability of VO 2 intelligent windows. Herein, we firstly deposited amorphous Ta 2 O 5 nanoparticles on VO 2 film by the magnetron sputtering method. It was found that the amorphous nano-Ta 2 O 5 coating possessed a favorable anti-biofouling capability against Pseudomonas aeruginosa as an environmental microorganism model, behind which lay the mechanism that the amorphous nano-Ta 2 O 5 could interrupt the microbial membrane electron transport chain and significantly elevate the intracellular reactive oxygen species (ROS) level. A plausible relationship was established between the anti-biofouling activity and physicochemical nature of amorphous Ta 2 O 5 nanoparticles from the perspective of defect chemistry. ROS-induced oxidative damage gave rise to microbial viability loss. In addition, the amorphous nano-Ta 2 O 5 coating can endow VO 2 with favorable cytocompatibility with human skin fibroblasts. This study may provide new insights into understanding the anti-biofouling and antimicrobial actions of amorphous transition metal oxide nanoparticles, which is conducive to expanding their potential applications in environmental fields.

Biofouling in forward osmosis systems: An experimental and numerical study.

PubMed

Bucs, Szilárd S; Valladares Linares, Rodrigo; Vrouwenvelder, Johannes S; Picioreanu, Cristian

2016-12-01

This study evaluates with numerical simulations supported by experimental data the impact of biofouling on membrane performance in a cross-flow forward osmosis (FO) system. The two-dimensional numerical model couples liquid flow with solute transport in the FO feed and draw channels, in the FO membrane support layer and in the biofilm developed on one or both sides of the membrane. The developed model was tested against experimental measurements at various osmotic pressure differences and in batch operation without and with the presence of biofilm on the membrane active layer. Numerical studies explored the effect of biofilm properties (thickness, hydraulic permeability and porosity), biofilm membrane surface coverage, and biofilm location on salt external concentration polarization and on the permeation flux. The numerical simulations revealed that (i) when biofouling occurs, external concentration polarization became important, (ii) the biofilm hydraulic permeability and membrane surface coverage have the highest impact on water flux, and (iii) the biofilm formed in the draw channel impacts the process performance more than when formed in the feed channel. The proposed mathematical model helps to understand the impact of biofouling in FO membrane systems and to develop possible strategies to reduce and control biofouling. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anti-biofouling function of amorphous nano-Ta2O5 coating for VO2-based intelligent windows

NASA Astrophysics Data System (ADS)

Li, Jinhua; Guo, Geyong; Wang, Jiaxing; Zhou, Huaijuan; Shen, Hao; Yeung, Kelvin W. K.

2017-04-01

From environmental and health perspectives, the acquisition of a surface anti-biofouling property holds important significance for the usability of VO2 intelligent windows. Herein, we firstly deposited amorphous Ta2O5 nanoparticles on VO2 film by the magnetron sputtering method. It was found that the amorphous nano-Ta2O5 coating possessed a favorable anti-biofouling capability against Pseudomonas aeruginosa as an environmental microorganism model, behind which lay the mechanism that the amorphous nano-Ta2O5 could interrupt the microbial membrane electron transport chain and significantly elevate the intracellular reactive oxygen species (ROS) level. A plausible relationship was established between the anti-biofouling activity and physicochemical nature of amorphous Ta2O5 nanoparticles from the perspective of defect chemistry. ROS-induced oxidative damage gave rise to microbial viability loss. In addition, the amorphous nano-Ta2O5 coating can endow VO2 with favorable cytocompatibility with human skin fibroblasts. This study may provide new insights into understanding the anti-biofouling and antimicrobial actions of amorphous transition metal oxide nanoparticles, which is conducive to expanding their potential applications in environmental fields.

In situ observation of the growth of biofouling layer in osmotic membrane bioreactors by multiple fluorescence labeling and confocal laser scanning microscopy.

PubMed

Yuan, Bo; Wang, Xinhua; Tang, Chuyang; Li, Xiufen; Yu, Guanghui

2015-05-15

Since the concept of the osmotic membrane bioreactor (OMBR) was introduced in 2008, it has attracted growing interests for its potential applications in wastewater treatment and reclamation; however, the fouling mechanisms of forward osmosis (FO) membrane especially the development of biofouling layer in the OMBR are not yet clear. Here, the fouled FO membranes were obtained from the OMBRs on days 3, 8 and 25 in sequence, and then the structure and growing rule of the biofouling layer formed on the FO membrane samples were in-situ characterized by multiple fluorescence labeling and confocal laser scanning microscopy (CLSM). CLSM images indicated that the variations in abundance and distribution of polysaccharides, proteins and microorganisms in the biofouling layer during the operation of OMBRs were significantly different. Before the 8th day, their biovolume dramatically increased. Subsequently, the biovolumes of β-d-glucopyranose polysaccharides and proteins continued increasing and leveled off after 8 days, respectively, while the biovolumes of α-d-glucopyranose polysaccharides and microorganisms decreased. Extracellular polymeric substances (EPS) played a significant role in the formation and growth of biofouling layer, while the microorganisms were seldom detected on the upper fouling layer after 3 days. Based on the results obtained in this study, the growth of biofouling layer on the FO membrane surface in the OMBR could be divided into three stages. Initially, EPS was firstly deposited on the FO membrane surface, and then microorganisms associated with EPS located in the initial depositing layer to form clusters. After that, the dramatic increase of the clusters of EPS and microorganisms resulted in the quick growth of biofouling layer during the flux decline of the OMBR. However, when the water flux became stable in the OMBR, some microorganisms and EPS would be detached from the FO membrane surface. Copyright © 2015 Elsevier Ltd. All rights reserved.

Countermeasures to Microbiofouling in Simulated Ocean Thermal Energy Conversion Heat Exchangers with Surface and Deep Ocean Waters in Hawaii

PubMed Central

Berger, Leslie Ralph; Berger, Joyce A.

1986-01-01

Countermeasures to biofouling in simulated ocean thermal energy conversion heat exchangers have been studied in single-pass flow systems, using cold deep and warm surface ocean waters off the island of Hawaii. Manual brushing of the loops after free fouling periods removed most of the biofouling material. However, over a 2-year period a tenacious film formed. Daily free passage of sponge rubber balls through the tubing only removed the loose surface biofouling layer and was inadequate as a countermeasure in both titanium and aluminum alloy tubes. Chlorination at 0.05, 0.07, and 0.10 mg liter-1 for 1 h day-1 lowered biofouling rates. Only at 0.10 mg liter-1 was chlorine adequate over a 1-year period to keep film formation and heat transfer resistance from rising above the maximum tolerated values. Lower chlorination regimens led to the buildup of uneven or patchy films which produced increased flow turbulence. The result was lower heat transfer resistance values which did not correlate with the amount of biofouling. Surfaces which were let foul and then treated with intermittent or continuous chlorination at 0.10 mg of chlorine or less per liter were only partially or unevenly cleaned, although heat transfer measurements did not indicate that fact. It took continuous chlorination at 0.25 mg liter-1 to bring the heat transfer resistance to zero and eliminate the fouling layer. Biofouling in deep cold seawater was much slower than in the warm surface waters. Tubing in one stainless-steel loop had a barely detectable fouling layer after 1 year in flow. With aluminum alloys sufficient corrosion and biofouling material accumulated to require that some fouling coutermeasure be used in long-term operation of an ocean thermal energy conversion plant. Images PMID:16347076

Exploring the mechanisms of rising bubbles in marine biofouling prevention

NASA Astrophysics Data System (ADS)

Menesses, Mark; Belden, Jesse; Dickenson, Natasha; Bird, James

2015-11-01

Fluid motion, such as flow past a ship, is known to inhibit the growth of marine biofouling. Bubbles rising along a submerged structure also exhibit this behavior, which is typically attributed to buoyancy induced flow. However, the bubble interface may also have a direct influence on inhibiting growth that is independent of the surrounding flow. Here we aim to decouple these two mechanisms through a combination of field and laboratory experiments. In this study, a wall jet and a stream of bubbles are used to create two flows near a submerged solid surface where biofouling occurs. The flow structure characteristics were recorded using PIV. This experimental analysis allows for us to compare the efficacy of each flow relative to its flow parameters. Exploration of the mechanisms at play in the prevention of biofouling by use of rising bubbles provides a foundation to predict and optimize this antifouling technique under various conditions.

Measuring a critical stress for continuous prevention of marine biofouling accumulation with aeration.

PubMed

Menesses, Mark; Belden, Jesse; Dickenson, Natasha; Bird, James

2017-10-01

When cleaning the hull of a ship, significant shear stresses are needed to remove established biofouling organisms. Given that there exists a link between the amount of time that fouling accumulates and the stress required to remove it, it is not surprising that more frequent grooming requires less shear stress. Yet, it is unclear if there is a minimum stress needed to prevent the growth of macrofouling in the limit of continuous grooming. This manuscript shows that single bubble stream aeration provides continuous grooming and prevents biofouling accumulation in regions where the average wall stress exceeds ~0.01 Pa. This value was found by comparing observations of biofouling growth from field studies with complementary laboratory measurements that probe the associated flow fields. These results suggest that aeration and other continuous grooming systems must exceed a wall stress of 0.01 Pa to prevent macrofouling accumulation.

The Design, Development, and Evaluation of a Differential Pressure Gauge Directional Wave Monitor.

DTIC Science & Technology

1982-10-01

Figure III-4). The isolation diaphragms are made of 13 mil DuPont Fairprene elastomer mounted on an acrylic housing. Fairpreneo is a durable nylon...material, coated with neoprene, that is flexible perpendicular to the plane of the fabric. The elastomer is sealed to its acrylic housing 4 by a 90-10...copper-nickel alloy ring. The 90-10 alloy was picked for its anti-fouling properties. Bio-fouling across the diaphragm ring could puncture the elastomer

Biofouling and biocorrosion in industrial water systems.

PubMed

Coetser, S E; Cloete, T E

2005-01-01

Corrosion associated with microorganisms has been recognized for over 50 years and yet the study of microbiologically influenced corrosion (MIC) is relatively new. MIC can occur in diverse environments and is not limited to aqueous corrosion under submerged conditions, but also takes place in humid atmospheres. Biofouling of industrial water systems is the phenomenon whereby surfaces in contact with water are colonized by microorganisms, which are ubiquitous in our environment. However, the economic implications of biofouling in industrial water systems are much greater than many people realize. In a survey conducted by the National Association of Corrosion Engineers of the United States ten years ago, it was found that many corrosion engineer did not accept the role of bacteria in corrosion, and many of then that did, could not recognize and mitigate the problem. Biofouling can be described in terms of its effects on processes and products such as material degradation (bio-corossion), product contamination, mechanical blockages, and impedance of heat transfer. Microorganisms distinguish themselves from other industrial water contaminants by their ability to utilize available nutrient sources, reproduce, and generate intra- and extracellular organic and inorganic substances in water. A sound understanding of the molecular and physiological activities of the microorganisms involved is necessary before strategies for the long term control of biofouling can be format. Traditional water treatment strategies however, have largely failed to address those factors that promote biofouling activities and lead to biocorrosion. Some of the major developments in recent years have been a redefinition of biofilm architecture and the realization that MIC of metals can be best understood as biomineralization.

Biofouling in photobioreactors for marine microalgae.

PubMed

Zeriouh, Ouassim; Reinoso-Moreno, José Vicente; López-Rosales, Lorenzo; Cerón-García, María Del Carmen; Sánchez-Mirón, Asterio; García-Camacho, Francisco; Molina-Grima, Emilio

2017-12-01

The economic and/or energetic feasibility of processes based on using microalgae biomass requires an efficient cultivation system. In photobioreactors (PBRs), the adhesion of microalgae to the transparent PBR surfaces leads to biofouling and reduces the solar radiation penetrating the PBR. Light reduction within the PBR decreases biomass productivity and, therefore, the photosynthetic efficiency of the cultivation system. Additionally, PBR biofouling leads to a series of further undesirable events including changes in cell pigmentation, culture degradation, and contamination by invasive microorganisms; all of which can result in the cultivation process having to be stopped. Designing PBR surfaces with proper materials, functional groups or surface coatings, to prevent microalgal adhesion is essential for solving the biofouling problem. Such a significant advance in microalgal biotechnology would enable extended operational periods at high productivity and reduce maintenance costs. In this paper, we review the few systematic studies performed so far and applied the existing thermodynamic and colloidal theories for microbial biofouling formation in order to understand microalgal adhesion on PBR surfaces and the microalgae-microalgae cell interactions. Their relationship to the physicochemical properties of the solid PBR surface, the microalgae cell surfaces, and the ionic strength of the culture medium is discussed. The suitability and the applicability of such theories are reviewed. To this end, an example of biofouling formation on a commercial glass surface is presented for the marine microalgae Nannochloropsis gaditana. It highlights the adhesion dynamics and the inaccuracies of the process and the need for further refinement of previous theories so as to apply them to flowing systems, such as is the case for PBRs used to culture microalgae.

INVESTIGATIONS INTO BIOFOULING PHENOMENA IN FINE PORE AERATION DEVICES

EPA Science Inventory

Microbiologically-based procedures were used to describe biofouling phenomena on fine pore aeration devices and to determine whether biofilm characteristics could be related to diffuser process performance parameters. Fine pore diffusers were obtained from five municipal wastewa...

Biofouling of Cr-Nickel Spray Coated Films on Steel Surfaces

NASA Astrophysics Data System (ADS)

Yoshida, Kento; Kanematsu, Hideyuki; Kuroda, Daisuke; Ikigai, Hajime; Kogo, Takeshi; Yokoyama, Seiji

2012-03-01

Nowadays, corrosion of metals brings us serious economic loss and it often reaches several percentage of GNP. Particularly the marine corrosion was serious and the counter measure was very hard to be established, since the number of factors is huge and complicated. One of the complicated factors in marine corrosion is biofouling. Biofouling was classified into two main categories, microfouling and macrofouling. The former is composed of biofilm formation mainly. Marine bacteria are attached to material surfaces, seeking for nutrition in oligotrophic environment and they excrete polysaccharide to form biofilm on metal surfaces. Then larger living matters are attached on the biofilms to develop biofouling on metal surfaces, which often lead loss and failures of metals in marine environments. From the viewpoint of corrosion protection and maintenance of marine structures, biofouling should be mitigated as much as possible. In this study, we applied spray coating to steels and investigated if chromium-nickel spray coating could mitigate the biofouling, being compared with the conventional aluminium-zinc spray coating in marine environments. The specimens used for this investigation are aluminium, zinc, aluminium-zinc, stacked chromium/nickel and those films were formed on carbon steel (JIS SS400). And the pores formed by spray coating were sealed by a commercial reagent for some specimens. All of those specimens were immersed into sea water located at Marina Kawage (854-3, Chisato, Tsu, Mie Prefecture) in Ise Bay for two weeks. The depth of the specimen was two meter from sea water surface and the distance was always kept constant, since they were suspended from the floating pier. The temperature in sea water changed from 10 to 15 degrees Celsius during the immersion test. The biofouling behavior was investigated by low vacuum SEM (Hitachi Miniscope TM1000) and X-ray fluorescent analysis. When the spray coated specimens with and without sealing agents were compared, the former showed higher antifouling properties generally. Aluminium-zinc alloy spray coated films had higher antifouling property. And the anti-property decreased in this order: Al-Zn alloy spray coating > Zinc spray coating > Aluminium spray coating > Stacked chromium/nickel spray coating. Aluminium and zinc spray coating has been evaluated high conventionally for anti-biofouling in marine environment. However, the Cr/Ni spray coating showed pretty high anti-fouling property.

Microbe-surface interactions in biofouling and biocorrosion processes.

PubMed

Beech, Iwona B; Sunner, Jan A; Hiraoka, Kenzo

2005-09-01

The presence of microorganisms on material surfaces can have a profound effect on materials performance. Surface-associated microbial growth, i.e. a biofilm, is known to instigate biofouling. The presence of biofilms may promote interfacial physico-chemical reactions that are not favored under abiotic conditions. In the case of metallic materials, undesirable changes in material properties due to a biofilm (or a biofouling layer) are referred to as biocorrosion or microbially influenced corrosion (MIC). Biofouling and biocorrosion occur in aquatic and terrestrial habitats varying in nutrient content, temperature, pressure and pH. Interfacial chemistry in such systems reflects a wide variety of physiological activities carried out by diverse microbial populations thriving within biofilms. Biocorrosion can be viewed as a consequence of coupled biological and abiotic electron-transfer reactions, i.e. redox reactions of metals, enabled by microbial ecology. Microbially produced extracellular polymeric substances (EPS), which comprise different macromolecules, mediate initial cell adhesion to the material surface and constitute a biofilm matrix. Despite their unquestionable importance in biofilm development, the extent to which EPS contribute to biocorrosion is not well-understood. This review offers a current perspective on material/microbe interactions pertinent to biocorrosion and biofouling, with EPS as a focal point, while emphasizing the role atomic force spectroscopy and mass spectrometry techniques can play in elucidating such interactions.

Plasma deposition of silver nanoparticles on ultrafiltration membranes: antibacterial and anti-biofouling properties.

PubMed

Cruz, Mercedes Cecilia; Ruano, Gustavo; Wolf, Marcus; Hecker, Dominic; Vidaurre, Elza Castro; Schmittgens, Ralph; Rajal, Verónica Beatriz

2015-02-01

A novel and versatile plasma reactor was used to modify Polyethersulphone commercial membranes. The equipment was applied to: i) functionalize the membranes with low-temperature plasmas, ii) deposit a film of poly(methyl methacrylate) (PMMA) by Plasma Enhanced Chemical Vapor Deposition (PECVD) and, iii) deposit silver nanoparticles (SNP) by Gas Flow Sputtering. Each modification process was performed in the same reactor consecutively, without exposure of the membranes to atmospheric air. Scanning electron microscopy and transmission electron microscopy were used to characterize the particles and modified membranes. SNP are evenly distributed on the membrane surface. Particle fixation and transport inside membranes were assessed before- and after-washing assays by X-ray photoelectron spectroscopy depth profiling analysis. PMMA addition improved SNP fixation. Plasma-treated membranes showed higher hydrophilicity. Anti-biofouling activity was successfully achieved against Gram-positive ( Enterococcus faecalis ) and -negative ( Salmonella Typhimurium) bacteria. Therefore, disinfection by ultrafiltration showed substantial resistance to biofouling. The post-synthesis functionalization process developed provides a more efficient fabrication route for anti-biofouling and anti-bacterial membranes used in the water treatment field. To the best of our knowledge, this is the first report of a gas phase condensation process combined with a PECVD procedure in order to deposit SNP on commercial membranes to inhibit biofouling formation.

A new diatom growth inhibition assay using the XTT colorimetric method.

PubMed

Jiang, Weina; Akagi, Takuya; Suzuki, Hidekazu; Takimoto, Ayaka; Nagai, Hiroshi

2016-01-01

Marine biofouling, which leads to significant operational stress and economic damage on marine infrastructures, is a major problem in marine related industries. Currently, the most common way to avoid marine biofouling involves the use of biocidal products in surface coatings. However, the need for environmentally friendly antibiofouling compounds has increased rapidly with the recent global prohibition of harmful antifoulants, such as tributyltin (TBT). In particular, periphytic diatoms have been shown to contribute significantly to biofilms, which play an important role in biofouling. Therefore, inhibiting the proliferation of fouling diatoms is a very important step in the prevention of marine biofouling. In this study, we developed a new, rapid, accurate, and convenient growth inhibition assay using the XTT colorimetric method to prevent the growth of the fouling periphytic diatom, Nitzschia amabilis Hidek. Suzuki (replaced synonym, Nitzschia laevis Hustedt). The feasibility of this method was verified by determining the growth inhibition activities of two standard photosynthetic inhibitors, DCMU and CuSO4. However, neither inhibitor had any cytotoxic activities at the range of concentrations tested. Moreover, this method was applied by screening and purification of herbicidic but non-cytotoxic compounds from cyanobacteria extracts. Our results demonstrate the utility of this newly established growth inhibition assay for the identification of marine anti-biofouling compounds. Copyright © 2016 Elsevier Inc. All rights reserved.

Plasma deposition of silver nanoparticles on ultrafiltration membranes: antibacterial and anti-biofouling properties

PubMed Central

Cruz, Mercedes Cecilia; Ruano, Gustavo; Wolf, Marcus; Hecker, Dominic; Vidaurre, Elza Castro; Schmittgens, Ralph; Rajal, Verónica Beatriz

2015-01-01

A novel and versatile plasma reactor was used to modify Polyethersulphone commercial membranes. The equipment was applied to: i) functionalize the membranes with low-temperature plasmas, ii) deposit a film of poly(methyl methacrylate) (PMMA) by Plasma Enhanced Chemical Vapor Deposition (PECVD) and, iii) deposit silver nanoparticles (SNP) by Gas Flow Sputtering. Each modification process was performed in the same reactor consecutively, without exposure of the membranes to atmospheric air. Scanning electron microscopy and transmission electron microscopy were used to characterize the particles and modified membranes. SNP are evenly distributed on the membrane surface. Particle fixation and transport inside membranes were assessed before- and after-washing assays by X-ray photoelectron spectroscopy depth profiling analysis. PMMA addition improved SNP fixation. Plasma-treated membranes showed higher hydrophilicity. Anti-biofouling activity was successfully achieved against Gram-positive (Enterococcus faecalis) and -negative (Salmonella Typhimurium) bacteria. Therefore, disinfection by ultrafiltration showed substantial resistance to biofouling. The post-synthesis functionalization process developed provides a more efficient fabrication route for anti-biofouling and anti-bacterial membranes used in the water treatment field. To the best of our knowledge, this is the first report of a gas phase condensation process combined with a PECVD procedure in order to deposit SNP on commercial membranes to inhibit biofouling formation. PMID:26166926

Process-Oriented Review of Bacterial Quorum Quenching for Membrane Biofouling Mitigation in Membrane Bioreactors (MBRs)

PubMed Central

Bouayed, Naila; Dietrich, Nicolas; Lafforgue, Christine; Lee, Chung-Hak; Guigui, Christelle

2016-01-01

Quorum Quenching (QQ) has been developed over the last few years to overcome practical issues related to membrane biofouling, which is currently the major difficulty thwarting the extensive development of membrane bioreactors (MBRs). QQ is the disruption of Quorum Sensing (QS), cell-to-cell communication enabling the bacteria to harmonize their behavior. The production of biofilm, which is recognized as a major part of the biocake formed on a membrane surface, and which leads to biofouling, has been found to be one of the bacterial behaviors controlled by QS. Since the enzymatic disruption of QS was reported to be efficient as a membrane biofouling mitigation technique in MBRs, the application of QQ to lab-scale MBRs has been the subject of much research using different approaches under different operating conditions. This paper gives an overview of the effectiveness of QQ in mitigating membrane biofouling in MBRs. It is based on the results of previous studies, using two microbial strains, Rhodococcus sp. BH4 and Pseudomonas sp. 1A1. The effect of bacterial QQ on the physical phenomena of the MBR process is analyzed, adopting an original multi-scale approach. Finally, the potential influence of the MBR operating conditions on QQ effectiveness is discussed. PMID:27983578

Biofouling of various metal oxides in marine environment

NASA Astrophysics Data System (ADS)

Kougo, T.; Kuroda, D.; Wada, N.; Ikegai, H.; Kanematsu, H.

2012-03-01

Biofouling has induced serious problems in various industrial fields such as marine structures, bio materials, microbially induced corrosion (MIC) etc. The effects of various metals on biofouling have been investigated so far and the mechanism has been clarified to some extent(1,2), and we proposed that Fe ion attracted lots of bacteria and formed biofilm very easily(3). In this study, we investigated the possibility for biofouling of Pseudomonas aeruginosa on various metal oxides such as Fe2O3, TiO2, WO3, AgO, Cr2O3 etc. And in addition of such a model experiment on laboratory scale, they were immersed into actual sea water as well as artificial sea water. As for the preparation of metal oxides, commercial oxide powders were used as starting material and those whose particle sizes were under 100 micrometers were formed into pellets by a press. Some of them were heated to 700 °C and sintered for 10 hours at the temperatures. After the calcinations, they were immersed into the culture of P. aeruginosa at 35 °C in about one week. After the immersion, they were taken out of the culture and the biofouling behaviors were observed by optical microscopy, low pressure scanning electron microscopy (low pressure SEM) etc. Biofouling is generally classified into several steps. Firstly, conditioning films composed of organic matters were formed on specimens. Then bacterial were attached to the specimen's surfaces, seeking for conditioning films as nutrition. Then bacteria formed biofilm on the specimens. In marine environment, more larger living matters such as shells etc would be attached to biofilms. However, in the culture media, only biofilms were formed.

Heatable carbon nanotube composite membranes for sustainable recovery from biofouling

EPA Science Inventory

Membrane filtration is one of the most reliable methods for water and wastewater treatment, however wider application is limited due to biofouling caused by the accumulation of microorganisms on the membrane’s surface. Here we report a water filtration membrane with self-cl...

The influenced of PAC, zeolite, and Moringa oleifera as biofouling reducer (BFR) on hybrid membrane bioreactor of palm oil mill effluent (POME).

PubMed

Damayanti, A; Ujang, Z; Salim, M R

2011-03-01

The main objective of this work was to determine the effectiveness of various biofouling reducers (BFRs) to operational condition in hybrid membrane bioreactor (MBR) of palm oil mill effluent (POME). A series of tests involving three bench scale (100 L) hybrid MBR were operated at sludge retention times (SRTs) of 30 days with biofouling reducer (BFR). Three different biofouling reducers (BFRs) were powdered actived carbon (PAC), zeolite (Ze), and Moringa oleifera (Mo) with doses of 4, 8 and 12 g L(-1) respectively were used. Short-term filtration trials and critical flux tests were conducted. Results showed that, all BFRs successfully removed soluble microbial products (SMP), for PAC, Ze, and Mo at 58%, 42%, and 48%, respectively. At their optimum dosages, PAC provided above 70% reductions and 85% in fouling rates during the short-term filtration and critical flux tests. Copyright © 2010 Elsevier Ltd. All rights reserved.

Long-term effect on membrane fouling in a new membrane bioreactor as a pretreatment to seawater desalination.

PubMed

Jeong, Sanghyun; Rice, Scott A; Vigneswaran, Saravanamuthu

2014-08-01

Submerged membrane adsorption bio-reactors (SMABR) were investigated as a new pretreatment for seawater reverse osmosis (SWRO) desalination. They were tested with different doses of powder activated carbon (PAC) on-site for a long-term. The biofouling on the membrane was assessed in terms of DNA (cells) and polysaccharide distribution. MBR without PAC addition resulted in severe fouling on membrane. When PAC is added in the MBR, PAC could reduce the organic fouling. Hence the biofilm formation on membrane was reduced without any membrane damage. PAC also helped to remove low molecular weight (LMW) organics responsible for biofouling of RO membrane. A linear correlation between assimilable organic carbon (AOC) and LMW organics was observed. A small amount of PAC (2.4-8.0g of PAC/m(3) of seawater) was sufficient to reduce biofouling. It indicated that SMABR is an environmentally-friendly biological pretreatment to reduce biofouling for SWRO. Copyright © 2014 Elsevier Ltd. All rights reserved.

Microbial Adhesion and Biofilm Formation on Microfiltration Membranes: A Detailed Characterization Using Model Organisms with Increasing Complexity

PubMed Central

Vanysacker, L.; Denis, C.; Declerck, P.; Piasecka, A.; Vankelecom, I. F. J.

2013-01-01

Since many years, membrane biofouling has been described as the Achilles heel of membrane fouling. In the present study, an ecological assay was performed using model systems with increasing complexity: a monospecies assay using Pseudomonas aeruginosa or Escherichia coli separately, a duospecies assay using both microorganisms, and a multispecies assay using activated sludge with or without spiked P. aeruginosa. The microbial adhesion and biofilm formation were evaluated in terms of bacterial cell densities, species richness, and bacterial community composition on polyvinyldifluoride, polyethylene, and polysulfone membranes. The data show that biofouling formation was strongly influenced by the kind of microorganism, the interactions between the organisms, and the changes in environmental conditions whereas the membrane effect was less important. The findings obtained in this study suggest that more knowledge in species composition and microbial interactions is needed in order to understand the complex biofouling process. This is the first report describing the microbial interactions with a membrane during the biofouling development. PMID:23986906

Impact of higher alginate expression on deposition of Pseudomonas aeruginosa in radial stagnation point flow and reverse osmosis systems.

PubMed

Herzberg, Moshe; Rezene, Tesfalem Zere; Ziemba, Christopher; Gillor, Osnat; Mathee, Kalai

2009-10-01

Extracellular polymeric substances (EPS) have major impact on biofouling of reverse osmosis (RO) membranes. On one hand, EPS can reduce membrane permeability and on the other, EPS production by the primary colonizers may influence their deposition and attachment rate and subsequently affect the biofouling propensity of the membrane. The role of bacterial exopolysaccharides in bacterial deposition followed by the biofouling potential of an RO membrane was evaluated using an alginate overproducing (mucoid) Pseudomonas aeruginosa. The mucoid P. aeruginosa PAOmucA22 was compared with its isogenic nonmucoid prototypic parent PAO1 microscopically in a radial stagnation point flow (RSPF) system for their bacterial deposition characteristics. Then, biofouling potential of PAO1 and PAOmucA22 was determined in a crossflow rectangular plate-and-frame membrane cell, in which the strains were cultivated on a thin-film composite, polyamide, flat RO membrane coupon (LFC-1) under laminar flow conditions. In the RSPF system, the observed deposition rate of the mucoid strain was between 5- and 10-fold lower than of the wild type using either synthetic wastewater medium (with ionic strength of 14.7 mM and pH 7.4) or 15 mM KCl solution (pH of 6.2). The slower deposition rate of the mucoid strain is explained by 5- to 25-fold increased hydrophilicity of the mucoid strain as compared to the isogenic wild type, PAO1. Corroborating with these results, a significant delay in the onset of biofouling of the RO membrane was observed when the mucoid strain was used as the membrane colonizer, in which the observed time for the induced permeate flux decline was delayed (ca. 2-fold). In conclusion, the lower initial cell attachment of the mucoid strain decelerated biofouling of the RO membrane. Bacterial deposition and attachment is a critical step in biofilm formation and governed by intimate interactions between outer membrane proteins of the bacteria and the surface. Shielding these interactions by a hydrated and hydrophilic alginate capsule is shown to dramatically lessen the biofouling potential of the membrane colonizers.

Effects of biofouling on the sinking behavior of microplastics

NASA Astrophysics Data System (ADS)

Kaiser, David; Kowalski, Nicole; Waniek, Joanna J.

2017-12-01

Although plastic is ubiquitous in marine systems, our current knowledge of transport mechanisms is limited. Much of the plastic entering the ocean sinks; this is intuitively obvious for polymers such as polystyrene (PS), which have a greater density than seawater, but lower density polymers like polyethylene (PE) also occur in sediments. Biofouling can cause large plastic objects to sink, but this phenomenon has not been described for microplastics <5 mm. We incubated PS and PE microplastic particles in estuarine and coastal waters to determine how biofouling changes their sinking behavior. Sinking velocities of PS increased by 16% in estuarine water (salinity 9.8) and 81% in marine water (salinity 36) after 6 weeks of incubation. Thereafter sinking velocities decreased due to lower water temperatures and reduced light availability. Biofouling did not cause PE to sink during the 14 weeks of incubation in estuarine water, but PE started to sink after six weeks in coastal water when sufficiently colonized by blue mussels Mytilus edulis, and its velocity continued to increase until the end of the incubation period. Sinking velocities of these PE pellets were similar irrespective of salinity (10 vs. 36). Biofilm composition differed between estuarine and coastal stations, presumably accounting for differences in sinking behavior. We demonstrate that biofouling enhances microplastic deposition to marine sediments, and our findings should improve microplastic transport models.

Impact of spacer thickness on biofouling in forward osmosis.

PubMed

Valladares Linares, R; Bucs, Sz S; Li, Z; AbuGhdeeb, M; Amy, G; Vrouwenvelder, J S

2014-06-15

Forward osmosis (FO) indirect desalination systems integrate wastewater recovery with seawater desalination. Niche applications for FO systems have been reported recently, due to the demonstrated advantages compared to conventional high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Among them, wastewater recovery has been identified to be particularly suitable for practical applications. However, biofouling in FO membranes has rarely been studied in applications involving wastewater effluents. Feed spacers separating the membrane sheets in cross-flow systems play an important role in biofilm formation. The objective of this study was to determine the influence of feed spacer thickness (28, 31 and 46 mil) on biofouling development and membrane performance in a FO system, using identical cross-flow cells in parallel studies. Flux development, biomass accumulation, fouling localization and composition were determined and analyzed. For all spacer thicknesses, operated at the same feed flow and the same run time, the same amount of biomass was found, while the flux reduction decreased with thicker spacers. These observations are in good agreement with biofouling studies for RO systems, considering the key differences between FO and RO. Our findings contradict previous cross-flow studies on particulate/colloidal fouling, where higher cross-flow velocities improved system performance. Thicker spacers reduced the impact of biofouling on FO membrane flux. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biofouling attractants from a brown marine alga Ecklonia cava.

PubMed

Sidharthan, M; Viswanadh, G S; Kim, Kyoung Ho; Kim, Hyuk Jun; Shin, H W

2007-04-01

In recent years, industrial pollutants and the mountain forest fire ashes released into seawater cause damage to the marine environment, mainly it reduces the algal productivity in the inter tidal region. To get recover from the stress due to pollutants and to increase the growth and development of biofouling algae (benthic organisms), Ecklonia cava extract was investigated for its biofouling attracting efficiency. Bioactive guided fractions of E. cava extract derived from column chromatography were tested against spore attachment of a fouling alga, Ulva pertusa. Fraction B showed increased spore attachment rate with a maximum of 92 +/- 5%. This fraction was further analysed on HPLC, GC-Mass and NMR, deduced as pentadecanoic acid.

Effect of ship hull form on the resistance penalty from biofouling.

PubMed

Oliveira, Dinis; Larsson, Ann I; Granhag, Lena

2018-03-01

Hull biofouling is a well-known problem for the shipping industry, leading to increased resistance and fuel consumption. Considering that the effects of hull form on resistance are known to be higher for a less slender hull, it is hypothesised in this paper that the effect of biofouling roughness on resistance is also dependent on the hull form. To test this hypothesis, previously reported full-scale numerical results on a containership are re-analysed. Form effects on roughness penalties, corresponding to K ΔCT  = 0.058 ± 0.025, are observed at a low speed (19 knots, Re s  = 2.29 × 10 9 ), which are however cancelled out by traditionally neglected roughness effects on wave-making resistance at a higher speed (24 knots, Re s  = 2.89 × 10 9 ). It is concluded that hull form effects on biofouling penalties can be significant at low speeds, though not generalisable for higher speeds, namely when wave-making resistance corresponds to ≥ 29% of total resistance.

Bacterial Growth on Chitosan-Coated Polypropylene Textile

PubMed Central

Erben, D.; Hola, V.; Jaros, J.; Rahel, J.

2012-01-01

Biofouling is a problem common in all systems where microorganisms and aqueous environment meet. Prevention of biofouling is therefore important in many industrial processes. The aim of this study was to develop a method to evaluate the ability of material coating to inhibit biofilm formation. Chitosan-coated polypropylene nonwoven textile was prepared using dielectric barrier discharge plasma activation. Resistance of the textile to biofouling was then tested. First, the textile was submerged into a growth medium inoculated with green fluorescein protein labelled Pseudomonas aeruginosa. After overnight incubation at 33°C, the textile was observed using confocal laser scanning microscopy for bacterial enumeration and biofilm structure characterisation. In the second stage, the textile was used as a filter medium for prefiltered river water, and the pressure development on the in-flow side was measured to quantify the overall level of biofouling. In both cases, nontreated textile samples were used as a control. The results indicate that the chitosan coating exhibits antibacterial properties. The developed method is applicable for the evaluation of the ability to inhibit biofilm formation. PMID:23724330

Growth and survival of host pearl oyster Pinctada fucata martensii (Dunker, 1880) treated by different biofouling-clean methods in China

NASA Astrophysics Data System (ADS)

Li, Junhui; Yang, Chuangye; Wang, Qingheng; Du, Xiaodong; Deng, Yuewen

2018-07-01

Pearl oyster Pinctada fucata martensii is an economically important species farmed to produce round nucleated pearl in China. However, pearl oyster shells are commonly exposed to biofouling, which is manually cleaned. This study experimentally evaluates the effects of biofouling cleaning by Siganus fuscescens (Houttuyn, 1782) foraging on growth performance and pearl traits of host pearl oyster P. fucata martensii. Three groups designated as EG1, EG2 and EG3 were set in the experiment. In EG1, biofouling was manually cleaned every 2 weeks and oysters were cultured in natural sea conditions. In EG2, biofouling was cleaned by foraging behavior of S. fuscescens every 2 weeks and oysters were cultured in natural sea conditions. In EG3, oysters were farmed in the net cage where S. fuscescens were stored. The survival rate of EG2 was higher than those of EG1 and EG3 and the daily growth rates of length and weight of shell and the thickness and weight of pearl of EG3 were significantly larger than those of EG1 and EG2. The survival rate, daily growth rates of the length and weight of shell, and thickness and weight of pearl were not significantly different between EG1 and EG2. This study suggested S. fuscescens foraging could evidently improve survival of host pearl oyster, which is promising to improve pearl yield in pearl oyster farms in China.

Role of Reverse Divalent Cation Diffusion in Forward Osmosis Biofouling.

PubMed

Xie, Ming; Bar-Zeev, Edo; Hashmi, Sara M; Nghiem, Long D; Elimelech, Menachem

2015-11-17

We investigated the role of reverse divalent cation diffusion in forward osmosis (FO) biofouling. FO biofouling by Pseudomonas aeruginosa was simulated using pristine and chlorine-treated thin-film composite polyamide membranes with either MgCl2 or CaCl2 draw solution. We related FO biofouling behavior-water flux decline, biofilm architecture, and biofilm composition-to reverse cation diffusion. Experimental results demonstrated that reverse calcium diffusion led to significantly more severe water flux decline in comparison with reverse magnesium permeation. Unlike magnesium, reverse calcium permeation dramatically altered the biofilm architecture and composition, where extracellular polymeric substances (EPS) formed a thicker, denser, and more stable biofilm. We propose that FO biofouling was enhanced by complexation of calcium ions to bacterial EPS. This hypothesis was confirmed by dynamic and static light scattering measurements using extracted bacterial EPS with the addition of either MgCl2 or CaCl2 solution. We observed a dramatic increase in the hydrodynamic radius of bacterial EPS with the addition of CaCl2, but no change was observed after addition of MgCl2. Static light scattering revealed that the radius of gyration of bacterial EPS with addition of CaCl2 was 20 times larger than that with the addition of MgCl2. These observations were further confirmed by transmission electron microscopy imaging, where bacterial EPS in the presence of calcium ions was globular, while that with magnesium ions was rod-shaped.

The role of "inert" surface chemistry in marine biofouling prevention.

PubMed

Rosenhahn, Axel; Schilp, Sören; Kreuzer, Hans Jürgen; Grunze, Michael

2010-05-07

The settlement and colonization of marine organisms on submerged man-made surfaces is a major economic problem for many marine industries. The most apparent detrimental effects of biofouling are increased fuel consumption of ships, clogging of membranes and heat exchangers, disabled underwater sensors, and growth of biofoulers in aquaculture systems. The presently common-but environmentally very problematic-way to deal with marine biofouling is to incorporate biocides, which use biocidal products in the surface coatings to kill the colonizing organisms, into the surface coatings. Since the implementation of the International Maritime Organization Treaty on biocides in 2008, the use of tributyltin (TBT) is restricted and thus environmentally benign but effective surface coatings are required. In this short review, we summarize the different strategies which are pursued in academia and industry to better understand the mechanisms of biofouling and to develop strategies which can be used for industrial products. Our focus will be on chemically "inert" model surface coatings, in particular oligo- and poly(ethylene glycol) (OEG and PEG) functionalized surface films. The reasons for choosing this class of chemistry as an example are three-fold: Firstly, experiments on spore settlement on OEG and PEG coatings help to understand the mechanism of non-fouling of highly hydrated interfaces; secondly, these studies defy the common assumption that surface hydrophilicity-as measured by water contact angles-is an unambiguous and predictive tool to determine the fouling behavior on the surface; and thirdly, choosing this system is a good example for "interfacial systems chemistry": it connects the behavior of unicellular marine organisms with the antifouling properties of a hydrated surface coating with structural and electronic properties as derived from ab initio quantum mechanical calculations using the electronic wave functions of oxygen, hydrogen, and carbon. This short review is written to outline for non-experts the hierarchical structure in length- and timescale of marine biofouling and the role of surface chemistry in fouling prevention. Experts in the field are referred to more specialized recent reviews.

Determination of Adsorption Capacity and Kinetics of Amidoxime-Based Uranium Adsorbent Braided Material in Unfiltered Seawater Using a Flume Exposure System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gill, Gary A.; Kuo, Li-Jung; Strivens, Jonathan E.

PNNL has developed a recirculating flume system for exposing braided adsorbent material to natural seawater under realistic temperature and flow-rate exposure conditions. The flumes are constructed of transparent acrylic material; they allow external light to pass into the flumes and permit photosynthetic growth of naturally present marine organisms (biofouling). Because the system consists of two flumes, replicate experiments can be conducted in which one of the flumes can be manipulated relative to the other. For example, one flume can be darkened to eliminate light exposure by placing a black tarp over the flume such that dark/light experiments can be conducted.more » Alternatively, two different braided adsorbents can be exposed simultaneously with no potential cross contamination issues. This report describes the first use of the PNNL flume system to study the impact of biofouling on adsorbent capacity. Experiments were conducted with the ORNL AI8 braided adsorbent material in light-exposed and darkened flumes for a 42-day exposure experiment. The major objective of this effort is to develop a system for the exposure of braided adsorbent material to unfiltered seawater, and to demonstrate the system by evaluating the performance of adsorption material when it is exposed to natural marine biofouling as it would be when the technology is used in the marine environment. Exposures of amidoxime-based polymeric braid adsorbents prepared by Oak Ridge Natural Laboratory (ORNL) were exposed to ambient seawater at 20°C in a flume system. Adsorption kinetics and adsorption capacity were assessed using time series determinations of uranium adsorption and one-site ligand saturation modeling. Biofouling in sunlight surface seawater has the potential to significantly add substantial biogenic mass to adsorption material when it is exposed for periods greater than 21 days. The observed biomass increase in the light flume was approximately 80% of the adsorbent mass after 42 days. The amount of biomass increase retained by the adsorbent in the dark flume was only a quarter of that observed in the light-exposed flume. Biofouling in sunlit surface seawater has the potential to reduce uranium adsorption capacity by ~30% after 42 days of exposure. Minimal or no adsorption loss due to biofouling occurred in the dark flume exposure. Attempts to assess time series measurements of uranium adsorption capacity using “snips” off a master braid are fraught with problems due to the inability to easily determine the mass of the adsorbent material when the biofouling is present. The ability to determine the adsorption of biogenically important trace elements (e.g. Fe, Mn, Zn, Cu, and Sr) on biofouled adsorbents is also problematic.« less

Involvement of reactive oxygen species in the electrochemical inhibition of barnacle (Amphibalanus amphitrite) settlement

Treesearch

Rodolfo E. Perez-Roa; Marc A. Anderson; Dan Rittschof; Christopher G. Hunt; Daniel R. Noguera

2009-01-01

The role of reactive oxygen species (ROS) in electrochemical biofouling inhibition was investigated using a series of abiotic tests and settlement experiments with larvae of the barnacle Amphibalanus amphitrite, a cosmopolitan fouler. Larval settlement, a measure of biofouling potential, was reduced from 43% ± 14% to 5% ± 6% upon the application of...

Study to determine the aquatic biological effects on the Solid Rocket Booster (SRB). [technique for monitoring marine microbial fouling

NASA Technical Reports Server (NTRS)

Colwell, R. R.; Zachary, A.

1979-01-01

The surface of the reusable solid rocket boosters (SRB), which are jettisoned from the Shuttle Orbiter to parachute in the sea, are studied for colonization by marine life. Techniques for monitoring the marine microbial fouling of SRB materials are presented. An assessment of the nature and degree of the biofouling expected on the SRB materials in the recovery zone is reported. A determination of the degree and the effects of seasonal variation occurring on microbial fouling in the retrieval zone waters is made. The susceptibility of the SRB parachute recovery system to microbial fouling and biodeterioration is investigated. The development of scanning electron microscopy and epifluorescence microscopic observation techniques for rapid assessment of microbial fouling is discussed.

Nitric Oxide Treatment for the Control of Reverse Osmosis Membrane Biofouling

PubMed Central

Barnes, Robert J.; Low, Jiun Hui; Bandi, Ratnaharika R.; Tay, Martin; Chua, Felicia; Aung, Theingi; Fane, Anthony G.; Kjelleberg, Staffan

2015-01-01

Biofouling remains a key challenge for membrane-based water treatment systems. This study investigated the dispersal potential of the nitric oxide (NO) donor compound, PROLI NONOate, on single- and mixed-species biofilms formed by bacteria isolated from industrial membrane bioreactor and reverse osmosis (RO) membranes. The potential of PROLI NONOate to control RO membrane biofouling was also examined. Confocal microscopy revealed that PROLI NONOate exposure induced biofilm dispersal in all but two of the bacteria tested and successfully dispersed mixed-species biofilms. The addition of 40 μM PROLI NONOate at 24-h intervals to a laboratory-scale RO system led to a 92% reduction in the rate of biofouling (pressure rise over a given period) by a bacterial community cultured from an industrial RO membrane. Confocal microscopy and extracellular polymeric substances (EPS) extraction revealed that PROLI NONOate treatment led to a 48% reduction in polysaccharides, a 66% reduction in proteins, and a 29% reduction in microbial cells compared to the untreated control. A reduction in biofilm surface coverage (59% compared to 98%, treated compared to control) and average thickness (20 μm compared to 26 μm, treated compared to control) was also observed. The addition of PROLI NONOate led to a 22% increase in the time required for the RO module to reach its maximum transmembrane pressure (TMP), further indicating that NO treatment delayed fouling. Pyrosequencing analysis revealed that the NO treatment did not significantly alter the microbial community composition of the membrane biofilm. These results present strong evidence for the application of PROLI NONOate for prevention of RO biofouling. PMID:25636842

Vessel Biofouling Prevention and Management Options Report

DTIC Science & Technology

2015-03-01

Marine Reserve GNPD Galapagos National Park Directorate gpm Gallons per minute HST™ Hull Surface Treatment HullBUG Hull Bio -Mimetic Underwater...operators and hull cleaning equipment vendors. 2 VESSEL STRUCTURES SUBJECT TO BIOFOULING All submerged areas of the hull, including appendages and niche...categorized as proactive (preventative) and reactive (removal). Preventative measures include hull coatings that present bio -toxic surfaces to the immediate

Effect of Silver or Copper Nanoparticles-Dispersed Silane Coatings on Biofilm Formation in Cooling Water Systems

PubMed Central

Ogawa, Akiko; Kanematsu, Hideyuki; Sano, Katsuhiko; Sakai, Yoshiyuki; Ishida, Kunimitsu; Beech, Iwona B.; Suzuki, Osamu; Tanaka, Toshihiro

2016-01-01

Biofouling often occurs in cooling water systems, resulting in the reduction of heat exchange efficiency and corrosion of the cooling pipes, which raises the running costs. Therefore, controlling biofouling is very important. To regulate biofouling, we focus on the formation of biofilm, which is the early step of biofouling. In this study, we investigated whether silver or copper nanoparticles-dispersed silane coatings inhibited biofilm formation in cooling systems. We developed a closed laboratory biofilm reactor as a model of a cooling pipe and used seawater as a model for cooling water. Silver or copper nanoparticles-dispersed silane coating (Ag coating and Cu coating) coupons were soaked in seawater, and the seawater was circulated in the laboratory biofilm reactor for several days to create biofilms. Three-dimensional images of the surface showed that sea-island-like structures were formed on silane coatings and low concentration Cu coating, whereas nothing was formed on high concentration Cu coatings and low concentration Ag coating. The sea-island-like structures were analyzed by Raman spectroscopy to estimate the components of the biofilm. We found that both the Cu coating and Ag coating were effective methods to inhibit biofilm formation in cooling pipes. PMID:28773758

Principles of biofouling protection in marine sponges: a model for the design of novel biomimetic and bio-inspired coatings in the marine environment?

PubMed

Müller, Werner E G; Wang, Xiaohong; Proksch, Peter; Perry, Carole C; Osinga, Ronald; Gardères, Johan; Schröder, Heinz C

2013-08-01

The process of biofouling of marine structures and substrates, such as platforms or ship hulls, proceeds in multiple steps. Soon after the formation of an initial conditioning film, formed via the adsorption of organic particles to natural or man-made substrates, a population of different bacterial taxa associates under the formation of a biofilm. These microorganisms communicate through a complex quorum sensing network. Macro-foulers, e.g., barnacles, then settle and form a fouling layer on the marine surfaces, a process that globally has severe impacts both on the economy and on the environment. Since the ban of tributyltin, an efficient replacement of this antifouling compound by next-generation antifouling coatings that are environmentally more acceptable and also showing longer half-lives has not yet been developed. The sponges, as sessile filter-feeder animals, have evolved antifouling strategies to protect themselves against micro- and subsequent macro-biofouling processes. Experimental data are summarized and suggest that coating of the sponge surface with bio-silica contributes to the inhibition of the formation of a conditioning film. A direct adsorption of the surfaces by microorganisms can be impaired through poisoning the organisms with direct-acting secondary metabolites or toxic peptides. In addition, first, compounds from sponges have been identified that interfere with the anti-quorum sensing network. Sponge secondary metabolites acting selectively on diatom colonization have not yet been identified. Finally, it is outlined that direct-acting secondary metabolites inhibiting the growth of macro-fouling animals and those that poison the multidrug resistance pump are available. It is concluded that rational screening programs for inhibitors of the complex and dynamic problem of biofilm production, based on multidisciplinary studies and using sponges as a model, are required in the future.

Tough Amphiphilic Gels for Antifouling Applications

NASA Astrophysics Data System (ADS)

Villada, Laura M.

Biofouling is the attachment of unwanted organisms on a surface, and it is influenced by a host of variables including the chemistry of the material as well as both the surface and bulk properties, and controlling and understanding the effect of these properties is critical for the development of effective materials to combat biofouling. All surfaces that are submerged in water are subject to the rapid colonization of a wide range of marine organisms. Marine biofouling decreases fuel efficiency, costing the Navy millions of dollars in penalty, as well as having drastic environmental effects. Previous prevention of biofouling in marine systems has been accomplished by the administration of biocides and toxic coatings. In recent years, increased concerns about the impacts of these hazardous compounds into marine ecosystems has spurred efforts to develop cost effective, non-toxic, and durable anti-fouling coatings. Hydrogels, hydrophilic crosslinked networks, are being used to modify silicone marine coatings and have demonstrated potential at combatting biofouling. Understanding the impact of amphiphilic materials, i.e. their structure and properties, on biofouling is of great importance in order to address the need in the industry. In this study, poly(2-hydroxyethyl methacrylate) (HEMA) crosslinked networks were tailored to investigate the influence of their surface and bulk properties on biofouling. Previous research utilizing HEMA-siloxane gels suggested a relationship between molecular weight between crosslinks, M c, and the attachment of soft fouling sporelings of the green algae U. linza and adsorption of the protein bovine serum albumin (BSA), and the initial thrust of this dissertation was aimed at resolving this relationship. Gel composition was modified by varying the siloxane crosslinking agent and the siloxane hydrophobic monomer concentrations. The gels exhibited an increase in elastic modulus from 0.17 to 8.55 MPa that coincided with an increasing concentration of crosslinking agent. The resultant variation in network mesh size had the strongest correlation with the BSA adsorption (R2 = 0.90) and algal spore attachment (R2 = 0.73). The second system evaluated was based upon a new siloxane non-isocyanate urethane divinyl monomer (NIUDMA) that was synthesized using environmentally friendly methods in order to produce more mechanically durable gels. A crosslinked amphiphilic network was synthesized utilizing NIUDMA in conjunction with the relatively hydrophobic hexafluorobutyl methacrylate (HFBMA) with hydrophilic HEMA. The initial HFBMA and HEMA feed composition was varied, and the effect on gel properties was equated to anti-biofouling efficacy. The different gel compositions altered the surface chemistry slightly and the structure of their surface; however, the greatest difference was seen in the bulk structure and mechanical properties. The elastic moduli measured for these gels was much higher than the gels previously tested; it ranged from 2 MPa to as high as 140 MPa by varying the ratio of hydrophilic (20 - 90 mol%) to hydrophobic (0 - 70 mol%) monomer concentration. For the NIUDMA gels, the biofouling assays performed to probe the effect of gel properties included U. linza sporeling attachment, N. incerta diatom and C. lytica bacteria biofilm growth and removal, and A. Amphitrite adult barnacle reattachment. The most effective results were seen with the fouling release results of diatoms, with up to 96% reduction, and marine bacteria with up to 98% reduction after an applied water pressure of 138 kPa. These two microfouling marine organisms are part of the first stages of the biofouling process, and reducing their attachment and adhesion is critical for preventing or reducing the later stages. There were complex trends seen with the properties of the gels and the bioassay results. Overall, the NIUDMA10 networks had comparable results to commercial coatings against spores, diatoms and marine bacteria.

Calibration procedure for Slocum glider deployed optical instruments.

PubMed

Cetinić, Ivona; Toro-Farmer, Gerardo; Ragan, Matthew; Oberg, Carl; Jones, Burton H

2009-08-31

Recent developments in the field of the autonomous underwater vehicles allow the wide usage of these platforms as part of scientific experiments, monitoring campaigns and more. The vehicles are often equipped with sensors measuring temperature, conductivity, chlorophyll a fluorescence (Chl a), colored dissolved organic matter (CDOM) fluorescence, phycoerithrin (PE) fluorescence and spectral volume scattering function at 117 degrees, providing users with high resolution, real time data. However, calibration of these instruments can be problematic. Most in situ calibrations are performed by deploying complementary instrument packages or water samplers in the proximity of the glider. Laboratory calibrations of the mounted sensors are difficult due to the placement of the instruments within the body of the vehicle. For the laboratory calibrations of the Slocum glider instruments we developed a small calibration chamber where we can perform precise calibrations of the optical instruments aboard our glider, as well as sensors from other deployment platforms. These procedures enable us to obtain pre- and post-deployment calibrations for optical fluorescence instruments, which may differ due to the biofouling and other physical damage that can occur during long-term glider deployments. We found that biofouling caused significant changes in the calibration scaling factors of fluorescent sensors, suggesting the need for consistent and repetitive calibrations for gliders as proposed in this paper.

Modification of Silicone Elastomer Surfaces with Zwitterionic Polymers: Short-Term Fouling Resistance and Triggered Biofouling Release.

PubMed

Shivapooja, Phanindhar; Yu, Qian; Orihuela, Beatriz; Mays, Robin; Rittschof, Daniel; Genzer, Jan; López, Gabriel P

2015-11-25

We present a method for dual-mode-management of biofouling by modifying surface of silicone elastomers with zwitterionic polymeric grafts. Poly(sulfobetaine methacrylate) was grafted from poly(vinylmethylsiloxane) elastomer substrates using thiol-ene click chemistry and surface-initiated, controlled radical polymerization. These surfaces exhibited both fouling resistance and triggered fouling-release functionality. The zwitterionic polymers exhibited fouling resistance over short-term (∼hours) exposure to bacteria and barnacle cyprids. The biofilms that eventually accumulated over prolonged-exposure (∼days) were easily detached by applying mechanical strain to the elastomer substrate. Such dual-functional surfaces may be useful in developing environmentally and biologically friendly coatings for biofouling management on marine, industrial, and biomedical equipment because they can obviate the use of toxic compounds.

Mitigation of biofouling using coatings: Year 2. Quarterly progress report No. 1. Calspan report 6782-M-5

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyer, A.E.; King, R.W.

1982-01-15

Objectives of this project are to evaluate benefits associated with control of the surface energetic properties of materials used in heat exchangers; and to identify preferred ranges of these surface conditions that minimize deposits of biological fouling known to deteriorate heat exchange efficiencies in seawater, brackish water, and freshwater systems. The technical approach employed uses special diagnostic plates in novel flow cells where fluid flow conditions can be well-controlled, modifying the surface chemistry and surface energy of the plates with very thin coatings and examining the earliest events of biofouling caused by macromolecules and microbial organisms. For the present phasemore » of the project (Year 2), attention will be focussed on biofouling in a freshwater/brackish water system.« less

Selective suppression of in situ proliferation of scyphozoan polyps by biofouling.

PubMed

Feng, Song; Wang, Shi-Wei; Zhang, Guang-Tao; Sun, Song; Zhang, Fang

2017-01-30

An increase in marine artificial constructions has been proposed as a major cause of jellyfish blooms, because these constructions provide additional substrates for organisms at the benthic stage (polyps), which proliferate asexually and release a large amount of free-swimming medusae. These hard surfaces are normally covered by fouling communities, the components of which have the potential to impede the proliferation of polyps. In this study, we report an in situ experiment of polyp survival of four large scyphozoan species found in East Asian marginal seas that were exposed to biofouling, a universal phenomenon occurring on marine artificial constructions. Our results showed that the polyps of three species (Nemopilema nomurai, Cyanea nozaki, and Rhopilema esculentum) attached to the artificial surfaces were completely eliminated by biofouling within 7-8months, and only those of moon jellyfish (Aurelia sp.1) in the upper layers could multiply on both artificial materials and other organisms (e.g., ascidians and bryozoans). Fouling-associated competition and predation and suppressed asexual reproduction of podocysts were observed to contribute to the loss of polyps. This study shows that the natural distribution of polyps is defined by the biofouling community that colonizes the surfaces of artificial constructions. Consequently, the contribution of marine constructions to jellyfish bloom is limited only to the ability of the jellyfish species to reproduce asexually through budding and inhabit solid surfaces of fouling organisms in addition to inhabiting original artificial materials. We anticipate that fragile polyps will colonize and proliferate in harsh environments that are deleterious to biofouling, and we propose special attention to polyps in antifouling practices for excluding the possibility that they occupy the available ecological space. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of elastomeric seal plate surface chemistry on interface integrity in biofouling-prone systems: Evaluation of a hydrophobic "easy-release" silicone-epoxy coating for maintaining water seal integrity of a sliding neoprene/steel interface

NASA Astrophysics Data System (ADS)

Andolina, Vincent L.

The scientific hypothesis of this work is that modulation of the properties of hard materials to exhibit abrasion-reducing and low-energy surfaces will extend the functional lifetimes of elastomeric seals pressed against them in abrasive underwater systems. The initial motivation of this work was to correct a problem noted in the leaking of seals at major hydropower generating facilities subject to fouling by abrasive zebra mussel shells and extensive corrosion. Similar biofouling-influenced problems can develop at seals in medical devices and appliances from regulators in anesthetic machines and SCUBA diving oxygen supply units to autoclave door seals, injection syringe gaskets, medical pumps, drug delivery components, and feeding devices, as well as in food handling equipment like pasteurizers and transfer lines. Maritime and many other heavy industrial seal interfaces could also benefit from this coating system. Little prior work has been done to elucidate the relationship of seal plate surface properties to the friction and wear of elastomeric seals during sliding contacts of these articulating materials, or to examine the secondary influence of mineralized debris within the contacting interfaces. This investigation utilized the seal materials relevant to the hydropower application---neoprene elastomer against carbon steel---with and without the application of a silicone-epoxy coating (WearlonRTM 2020.98) selected for its wear-resistance, hydrophobicity, and "easy-release" capabilities against biological fouling debris present in actual field use. Analytical techniques applied to these materials before and after wear-producing processes included comprehensive Contact Angle measurements for Critical Surface Tension (CA-CST) determination, Scanning Electron Microscopic inspections, together with Energy Dispersive X-ray Spectroscopy (SEM-EDS) and X-Ray Fluorescence (XRF) measurements for determination of surface texture and inorganic composition, Multiple Attenuated Internal Reflection (MAIR-IR) and Microscopic Infrared Spectroscopy for organic surface compositional details, light microscopy for wear area quantification, and profilometry for surface roughness estimation and wear depth quantification. Pin-on-disc dynamic Coefficient of Friction (CoF) measurements provided data relevant to forecasts of seal integrity in dry, wet and biofouling-influenced sliding contact. Actual wear of neoprene seal material against uncoated and coated steel surfaces, wet and dry, was monitored after both rotary and linear cyclic wear testing, demonstrating significant reductions in elastomer wear areas and depths (and resultant volumes) when the coating was present. Coating the steel eliminated a 270% increase in neoprene surface area wear and an 11-fold increase in seal abrasive volume loss associated with underwater rusting in rotary experiments. Linear testing results confirm coating efficacy by reducing wear area in both loading regimes by about half. No coating delamination was observed, apparently due to a differential distribution of silicone and epoxy ingredients at the air-exposed vs. steel-bonded interfaces demonstrated by IR and EDS methods. Frictional testing revealed higher Coefficients of Friction (CoF) associated with the low-speed sliding of Neoprene over coated rather than uncoated steel surfaces in a wet environment, indicating better potential seal adhesion between the hydrophobic elastomer and coating than between the elastomer and intrinsically hydrophilic uncoated steel. When zebra mussel biofouling debris was present in the articulating joints, CoF was reduced as a result of a water channel path produced between the articulating surfaces by the retained biological matter. Easier release of the biofouling from the low-CST coated surfaces restored the seal integrity more rapidly with further water rinsing. Rapid sliding diminished these biofouling-related differences, but revealed a significant advantage in reducing the CoF of the elastomer-on-coating couples to less than 50% of the elastomer-on-steel couples in all conditions. These consolidated results indicate that general improvements in maintenance of seal integrity and functional lifetimes for other sliding joints exposed to potentially abrasive biofouling media can be obtained by coating the more-rigid seal-plate surfaces with low-CST, hydrophobic, wear-resistant materials such as the silicone-epoxy system characterized here.

Marine biosurfaces research program

NASA Astrophysics Data System (ADS)

The Office of Naval Research (ONR) of the U.S. Navy is starting a basic research program to address the initial events that control colonization of surfaces by organisms in marine environments. The program “arises from the Navy's need to understand and ultimately control biofouling and biocorrosion in marine environments,” according to a Navy announcement.The program, “Biological Processes Controlling Surface Modification in the Marine Environment,” will emphasize the application of in situ techniques and modern molecular biological, biochemical, and biophysical approaches; it will also encourage the development of interdisciplinary projects. Specific areas of interest include sensing and response to environmental surface (physiology/physical chemistry), factors controlling movement to and retention at surfaces (behavior/hydrodynamics), genetic regulation of attachment (molecular genetics), and mechanisms of attachment (biochemistry/surface chemistry).

The Anti-Biofouling Properties of Superhydrophobic Surfaces are Short-Lived.

PubMed

Hwang, Gi Byoung; Page, Kristopher; Patir, Adnan; Nair, Sean P; Allan, Elaine; Parkin, Ivan P

2018-06-12

Superhydrophobic surfaces are present in nature on the leaves of many plant species. Water rolls on these surfaces, and the rolling motion picks up particles including bacteria and viruses. Man-made superhydrophobic surfaces have been made in an effort to reduce biofouling. We show here that the anti-biofouling property of a superhydrophobic surface is due to an entrapped air-bubble layer that reduces contact between the bacteria and the surface. Further, we showed that prolonged immersion of superhydrophobic surfaces in water led to loss of the bubble-layer and subsequent bacterial adhesion that unexpectedly exceeded that of the control materials. This behavior was not restricted to one particular type of material but was evident on different types of superhydrophobic surfaces. This work is important in that it suggests that superhydrophobic surfaces may actually encourage bacterial adhesion during longer term exposure.

Linking microbial community structure to membrane biofouling associated with varying dissolved oxygen concentrations.

PubMed

Gao, Da-wen; Fu, Yuan; Tao, Yu; Li, Xin-xin; Xing, Min; Gao, Xiu-hong; Ren, Nan-qi

2011-05-01

In order to elucidate how dissolved oxygen (DO) concentration influenced the generation of extracellular polymeric substance (EPS) and soluble microbial products (SMP) in mixed liquor and biocake, 16S rDNA fingerprinting analyses were performed to investigate the variation of the microbial community in an aerobic membrane bioreactor (MBR). The function of microbial community structure was proved to be ultimately responsible for biofouling. Obvious microbial community succession from the subphylum of Betaproteobacteria to Deltaproteobacteria was observed in biocake. High concentration of EPS in biocake under the low DO concentration (0.5 mg L(-1)) caused severe biofouling. The correlation coefficient of membrane fouling rate with EPS content in biocake (0.9941-0.9964) was much higher than that in mixed liquor (0.6689-0.8004). Copyright © 2011 Elsevier Ltd. All rights reserved.

Fouling communities and degradation of archeological metals in the coastal sea of the Southwestern Gulf of Mexico.

PubMed

López Garrido, Pedro H; González-Sánchez, J; Escobar Briones, Elva

2015-01-01

Corrosion and biofouling phenomena of cast iron and brass were evaluated under natural conditions to determine the degradation process of archeological artifacts. Field exposure studies of experimental materials were conducted over 15 months at an offshore position in the sea of Campeche in the Gulf of Mexico. Corrosion was determined by gravimetric measurements. The community structure of the benthic assemblage inhabiting the surfaces of both materials was evaluated. A total of 53 species was identified. The community in both cases was composed of a small number of species. Encrusting, attached and erect life forms were dominant on iron. Attached life forms were dominant on brass. Biofouling produced a decrease in the weight loss measurements of cast iron samples. Biofouling provided a beneficial factor for in situ preservation of iron archeological artifacts in wreck sites.

Functionalizing aluminum substrata by quaternary ammonium for antifouling performances

NASA Astrophysics Data System (ADS)

He, Xiaoyan; Suo, Xinkun; Bai, Xiuqin; Yuan, Chengqing; Li, Hua

2018-05-01

Due to the great loss induced by biofouling, developing new strategies for combating biofouling has attracted extensive attention. Quaternary ammonium salts are potent cationic antimicrobials used in consumer products and their use for surface immobilization could create a contact-active antimicrobial layer. Here we report the facile preparation of a contact-active antifouling coating by tethering polyethyleneimine (PEI) onto flat/nanostructured aluminum surface by hydrogen bonding between PEI and AlOOH. Quaternized PEI (QPEI) is obtained through quaternization reactions. Biofouling testing suggests excellent antifouling performances of the samples by declining the adhesion of 95% Phaeodactylum tricornutum and 98% of Chlorella pyrenoidosa. The antifouling properties of PEI/QPEI are attributed predominately to their hydrophilic and antimicrobial nature. The technical route of PEI/QPEI surface grafting shows great potential for modifying marine infrastructures for enhanced antifouling performances.

Ennoblement, corrosion, and biofouling in brackish seawater: Comparison between six stainless steel grades.

PubMed

Huttunen-Saarivirta, E; Rajala, P; Marja-Aho, M; Maukonen, J; Sohlberg, E; Carpén, L

2018-04-01

In this work, six common stainless steel grades were compared with respect to ennoblement characteristics, corrosion performance and tendency to biofouling in brackish sea water in a pilot-scale cooling water circuit. Two tests were performed, each employing three test materials, until differences between the materials were detected. Open circuit potential (OCP) was measured continuously in situ. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements were conducted before and after the tests. Exposed specimens were further subjected to examinations by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), and the biofouling was studied using epifluorescence microscopy, quantitative polymerase chain reaction (qPCR) and high-throughput sequencing (HTP sequencing). The results revealed dissimilarities between the stainless steel grades in corrosion behaviour and biofouling tendency. The test material that differed from the most of the other studied alloys was grade EN 1.4162. It experienced fastest and most efficient ennoblement of OCP, its passive area shrank to the greatest extent and the cathodic reaction was accelerated to a significant degree by the development of biofilm. Furthermore, microbiological analyses revealed that bacterial community on EN 1.4162 was dominated by Actinobacteria, whereas on the other five test materials Proteobacteria was the main bacterial phylum. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of novel antibiofouling materials from natural phenol compounds

NASA Astrophysics Data System (ADS)

Chelikani, Rahul; Kim, Dong Shik

2007-03-01

Biofilms consist of a gelatinous matrix formed on a solid surface by microbial organisms.Biofilm is caused due to the adhesion of microbes to solid surfaces with production of extracellular polymers and the process of the biofilm formation is reffered to as biofouling.Biofouling causes serious problems in chemical, medical and pharmaceutical industries.Although there have been some antibiofouling materials developed over the years,no plausible results have been found yet.Natural polyphenolic compounds like flavanoids,cathechins have strong antioxidant and antimicrobial properties.Recently,apocynin,a phenol derivative,was polymerized to form oligomers,which can regulate intracellular pathways in cancer cells preventing cell proliferation and migration.These natural phenolic compounds have never been applied to solid surfaces to prevent biofouling.It is thought that probably because of the difficulty to crosslink them to form a stable coating.In this study,some novel polyphenolic compounds synthesized using enzymatic technique from cashew nut shell liquid,a cheap and renewable byproduct of the cashew industry are used as coating materials to prevent biofouling.The interaction of these materials with microbes preventing fouling on surfaces and the chemico-physical properties of the materials causing the antibiofouling effect will be discussed.It is critical to understand the antibiofouling mechanism of these materials for better design and application in various fields.

Effect of biological and coagulation pre-treatments to control organic and biofouling potential components of ultrafiltration membrane in the treatment of lake water.

PubMed

Pramanik, Biplob Kumar; Kajol, Annaduzzaman; Suja, Fatihah; Md Zain, Shahrom

2017-03-01

Biological aerated filter (BAF), sand filtration (SF), alum and Moringa oleifera coagulation were investigated as a pre-treatment for reducing the organic and biofouling potential component of an ultrafiltration (UF) membrane in the treatment of lake water. The carbohydrate content was mainly responsible for reversible fouling of the UF membrane compared to protein or dissolved organic carbon (DOC) content. All pre-treatment could effectively reduce these contents and led to improve the UF filterability. Both BAF and SF markedly led to improvement in flux than coagulation processes, and alum gave greater flux than M. oleifera. This was attributed to the effective removal and/or breakdown of high molecular weight (MW) organics by biofilters. BAF led to greater improvement in flux than SF, due to greater breakdown of high MW organics, and this was also confirmed by the attenuated total reflection-Fourier transform infrared spectroscopy analysis. Coagulation processes were ineffective in removing biofouling potential components, whereas both biofilters were very effective as shown by the reduction of low MW organics, biodegradable dissolved organic carbon and assimilable organic carbon contents. This study demonstrated the potential of biological pre-treatments for reducing organic and biofouling potential component and thus improving flux for the UF of lake water treatment.

Does chlorination of seawater reverse osmosis membranes control biofouling?

PubMed

Khan, Muhammad Tariq; Hong, Pei-Ying; Nada, Nabil; Croue, Jean Philippe

2015-07-01

Biofouling is the major problem of reverse osmosis (RO) membranes used for desalting seawater (SW). The use of chlorine is a conventional and common practice to control/prevent biofouling. Unlike polyamide RO membranes, cellulose triacetate (CTA) RO membranes display a high chlorine tolerance. Due to this characteristic, CTA membranes are used in most of the RO plants located in the Middle East region where the elevated seawater temperature and water quality promote the risk of membrane biofouling. However, there is no detailed study on the investigation/characterization of CTA-RO membrane fouling. In this investigation, the fouling profile of a full-scale SWRO desalination plant operating with not only continuous chlorination of raw seawater but also intermittent chlorination of CTA-RO membranes was studied. Detailed water quality and membrane fouling analyses were conducted. Profiles of microbiological, inorganic, and organic constituents of analysed fouling layers were extensively discussed. Our results clearly identified biofilm development on these membranes. The incapability of chlorination on preventing biofilm formation on SWRO membranes could be assigned to its failure in effectively reaching throughout the different regions of the permeators. This failure could have occurred due to three main factors: plugging of membrane fibers, chlorine consumption by organics accumulated on the front side fibers, or chlorine adaptation of certain bacterial populations. Copyright © 2015 Elsevier Ltd. All rights reserved.

Use of Seawater for Air Conditioning at Waikiki Convention Center

DTIC Science & Technology

1994-01-01

construct heat exchangers of either titanium or zinc-clad aluminum . It is likely that these could be ordered "off the shelf*. Bio-fouling would not be a...Considerations J. Fouling K. Alternative Design: Directional Drilling System Design A. Seawater Heat Exchangers 1. Materials 2. Bio-fouling 3. Design... Heat exchangers are available in a variety of types, sizes and materials . There are standard models available by many manufactures, however, a single

Control of invasive marine invertebrates: an experimental evaluation of the use of low salinity for managing pest corals (Tubastraea spp.).

PubMed

Moreira, Patrícia L; Ribeiro, Felipe V; Creed, Joel C

2014-01-01

This study investigated the use of low salinity as a killing agent for the invasive pest corals Tubastraea coccinea and Tubastraea tagusensis (Dendrophylliidae). Experiments investigated the efficacy of different salinities, the effect of colony size on susceptibility and the influence of length of exposure. Experimental treatments of colonies were carried out in aquaria. Colonies were then fixed onto experimental plates and monitored in the field periodically over a period of four weeks. The killing effectiveness of low salinity depended on the test salinity and the target species, but was independent of colony size. Low salinity was fast acting and prejudicial to survival: discoloration, necrosis, fragmenting and sloughing, exposure of the skeleton and cover by biofoulers occurred post treatment. For T. tagusensis, 50% mortality (LC50) after three days occurred at eight practical salinity units (PSU); for T. coccinea the LC50 was 2 PSU. Exposure to freshwater for 45-120 min resulted in 100% mortality for T. tagusensis, but only the 120 min period was 100% effective in killing T. coccinea. Freshwater is now routinely used for the post-border management of Tubastraea spp. This study also provides insights as to how freshwater may be used as a routine biosecurity management tool when applied pre-border to shipping vectors potentially transporting non-indigenous marine biofouling species.

Biofilm monitoring using complex permittivity.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Altman, Susan Jeanne; McGrath, Lucas K.; Dolan, Patricia L.

2008-10-01

There is strong interest in the detection and monitoring of bio-fouling. Bio-fouling problems are common in numerous water treatments systems, medical and dental apparatus and food processing equipment. Current bio-fouling control protocols are time consuming and costly. New early detection techniques to monitor bio-forming contaminates are means to enhanced efficiency. Understanding the unique dielectric properties of biofilm development, colony forming bacteria and nutrient background will provide a basis to the effectiveness of controlling or preventing biofilm growth. Dielectric spectroscopy measurements provide values of complex permittivity, {var_epsilon}*, of biofilm formation by applying a weak alternating electric field at various frequencies. Themore » dielectric characteristic of the biofilm, {var_epsilon}{prime}, is the real component of {var_epsilon}* and measures the biofilm's unique ability to store energy. Graphically observed dependencies of {var_epsilon}{prime} to frequency indicate dielectric relaxation or dielectric dispersion behaviors that mark the particular stage of progression during the development of biofilms. In contrast, any frequency dependency of the imaginary component, {var_epsilon}{double_prime} the loss factor, is expressed as dielectric losses from the biofilm due to dipole relaxation. The tangent angle of these two component vectors is the ratio of the imaginary component to the real component, {var_epsilon}{double_prime}/{var_epsilon}{prime} and is referred to as the loss angle tangent (tan {delta}) or dielectric loss. Changes in tan {delta} are characteristic of changes in dielectric losses during various developmental stages of the films. Permittivity scans in the above figure are of biofilm growth from P. Fluorescens (10e7 CFU's at the start). Three trends are apparent from these scans, the first being a small drop in the imaginary permittivity over a 7 hours period, best seen in the Cole-Cole plot (a). The second trend is observed two hours after inoculation when the permittivity begins to increase slightly over the next 20 hours, best seen in the shift from 1000 Hz to 5000 Hz in tan {delta} at the high frequencies (c). Because of similar dielectric relaxation properties noted by the comparable size of the semicircles, plot (a), and the height of tan {delta}, plot (c), within the first 29 hours, cell activity levels did not appreciably change. The third trend is observed when the complex permittivity value drops by orders of magnitude between 29 hours and 37 hours, best seen in the log [E] plot (b), and in the drop of the dielectric loss, tan {delta}, to 0. This change in the dielectric properties in the bio environment is nearly independent of all frequencies (c) and dissimilar from the original condition when only bacteria and nutrient was present in the biofilm chambers. The semicircles in plot (a) for this period decreased below the resolution of the graph, implying a large difference in the dielectric behavior of the cells/biofilms consisting of low dielectric losses. We believe these large changes are related to the on-set of biofilms.« less

Fabrication of Slippery Lubricant-Infused Porous Surface with High Underwater Transparency for the Control of Marine Biofouling.

PubMed

Wang, Peng; Zhang, Dun; Sun, Shimei; Li, Tianping; Sun, Yan

2017-01-11

Marine optical instruments are bearing serious biofouling problem, which affects the accuracy of data collected. To solve the biofouling problem of marine optical instruments, a novel instance of slippery lubricant-infused porous surface (SLIPS) with high underwater-transparency was designed over glass substrate via infusing lubricant into its porous microstructure fabricated with hydrothermal method. The advantage of SLIPS as antibiofouling strategy to marine optical instruments was proven by comparing its underwater optical and antibiofouling performances with three kinds of samples (hydrophilic glass sample, textured hydrophilic glass sample, and superhydrophobic glass sample). The modification of SLIPS enhances the underwater-transparency of glass sample within the wavelength of 500-800 nm, for the infusion of lubricant with lower refractive index than glass substrate. In contrast with hydrophilic surface, textured hydrophilic surface and superhydrophobic surface, SLIPS can significantly inhibit bacterial and algal settlements, thereby maintaining high underwater-transparency in both dynamic and static seawater. The inhibition of bacterial and algal settlements over SLIPS results from its liquid-like property. The contact angle hysteresis of water over SLIPS increases with immersion time in seawater under different conditions (static, dynamic, and vibration conditions). Both dynamic and vibration conditions accelerate the failure of SLIPS exposed in seawater. This research provides valuable information for solving biofouling problem of marine optical instruments with SLIPS.

The role of environmental biotechnology in exploring, exploiting, monitoring, preserving, protecting and decontaminating the marine environment.

PubMed

Kalogerakis, Nicolas; Arff, Johanne; Banat, Ibrahim M; Broch, Ole Jacob; Daffonchio, Daniele; Edvardsen, Torgeir; Eguiraun, Harkaitz; Giuliano, Laura; Handå, Aleksander; López-de-Ipiña, Karmele; Marigomez, Ionan; Martinez, Iciar; Øie, Gunvor; Rojo, Fernando; Skjermo, Jorunn; Zanaroli, Giulio; Fava, Fabio

2015-01-25

In light of the Marine Strategy Framework Directive (MSFD) and the EU Thematic Strategy on the Sustainable Use of Natural Resources, environmental biotechnology could make significant contributions in the exploitation of marine resources and addressing key marine environmental problems. In this paper 14 propositions are presented focusing on (i) the contamination of the marine environment, and more particularly how to optimize the use of biotechnology-related tools and strategies for predicting and monitoring contamination and developing mitigation measures; (ii) the exploitation of the marine biological and genetic resources to progress with the sustainable, eco-compatible use of the maritime space (issues are very diversified and include, for example, waste treatment and recycling, anti-biofouling agents; bio-plastics); (iii) environmental/marine biotechnology as a driver for a sustainable economic growth. Copyright © 2014 Elsevier B.V. All rights reserved.

Iron in the aquifer system of Suffolk County, New York, 1990–98

USGS Publications Warehouse

Brown, Craig J.; Walter, Donald A.; Colabufo, Steven

1999-01-01

High concentrations of dissolved iron in ground water contribute to the biofouling of public-supply wells, and the treatment and remediation of biofouling are costly. Water companies on Long Island, N.Y., spend several million dollars annually to recondition, redevelop, and replace supply wells and distribution lines; treat dissolved iron with sequestering agents or by filtration; and respond to iron-related complaints by customers. This report summarizes the results of studies done by the U.S. Geological Survey, in cooperation with the Suffolk County Water Authority, to characterize the geochemistry and microbiology of iron in the aquifer system of Suffolk County. This information should be helpful for the siting and operation of supply wells.Concentrations of dissolved iron in Long Island's ground water, and the frequency of iron biofouling of wells, are highest in ground-water-discharge zones, particularly near the south shore. Ground water along a deep north-south flowpath of the Magothy aquifer in southwestern Suffolk County becomes anaerobic (oxygen deficient) and Fe(III) reducing at a distance of 8 to 10 kilometers south of the ground-water divide, and this change coincides with the downgradient increase in dissolved iron concentrations. The distribution of organic carbon, and the distribution and local variations in reactivity of Fe(III), in Magothy aquifer sediments have resulted in localized differences in redox microenvironments. For example, Fe(III)-reducing zones are associated with anaerobic conditions, where relatively large amounts of Fe(III) oxyhydroxide grain coatings are present, whereas sulfate-reducing zones are associated with lignite-rich lenses of silt and clay and appear to have developed in response to the depletion of available Fe(III) oxyhydroxides. The sulfate-reducing zones are characterized by relatively low concentrations of dissolved iron (resulting from iron-disulfide precipitation) and may be large enough to warrant water-supply development.Specific-capacity and water-quality data from wells screened in the Magothy aquifer indicate that water from biofouled wells contains higher median concentrations of total and dissolved iron and manganese, total phosphate, and dissolved sulfate, and lower median concentrations of dissolved oxygen and alkalinity, and lower pH, than does water from unaffected wells. Corresponding data from wells screened in the upper glacial aquifer indicate that water from biofouled wells contains higher median concentrations of total and dissolved manganese and dissolved sulfate, and lower pH, than does water from unaffected wells.Filamentous bacteria were detected in 31 (or 72 percent) of the 43 biofilm samples obtained from biofouled wells during reconditioning. The predominant filamentous organism was Gallionella ferruginea, a major biofouling agent in the upper glacial and Magothy aquifers throughout Suffolk County. Mineral-saturation indices indicate that most of the well-encrusting material is deposited when the wells are shut down. Furthermore, the use of treated water (which has a high pH and sometimes high concentrations of dissolved iron) for pump prelubrication when wells are shut down could greatly increase the rate of iron oxidation.

Extremely durable biofouling-resistant metallic surfaces based on electrodeposited nanoporous tungstite films on steel

PubMed Central

Tesler, Alexander B.; Kim, Philseok; Kolle, Stefan; Howell, Caitlin; Ahanotu, Onye; Aizenberg, Joanna

2015-01-01

Formation of unwanted deposits on steels during their interaction with liquids is an inherent problem that often leads to corrosion, biofouling and results in reduction in durability and function. Here we report a new route to form anti-fouling steel surfaces by electrodeposition of nanoporous tungsten oxide (TO) films. TO-modified steels are as mechanically durable as bare steel and highly tolerant to compressive and tensile stresses due to chemical bonding to the substrate and island-like morphology. When inherently superhydrophilic TO coatings are converted to superhydrophobic, they remain non-wetting even after impingement with yttria-stabilized-zirconia particles, or exposure to ultraviolet light and extreme temperatures. Upon lubrication, these surfaces display omniphobicity against highly contaminating media retaining hitherto unseen mechanical durability. To illustrate the applicability of such a durable coating in biofouling conditions, we modified naval construction steels and surgical instruments and demonstrated significantly reduced marine algal film adhesion, Escherichia coli attachment and blood staining. PMID:26482559

Extremely durable biofouling-resistant metallic surfaces based on electrodeposited nanoporous tungstite films on steel

NASA Astrophysics Data System (ADS)

Tesler, Alexander B.; Kim, Philseok; Kolle, Stefan; Howell, Caitlin; Ahanotu, Onye; Aizenberg, Joanna

2015-10-01

Formation of unwanted deposits on steels during their interaction with liquids is an inherent problem that often leads to corrosion, biofouling and results in reduction in durability and function. Here we report a new route to form anti-fouling steel surfaces by electrodeposition of nanoporous tungsten oxide (TO) films. TO-modified steels are as mechanically durable as bare steel and highly tolerant to compressive and tensile stresses due to chemical bonding to the substrate and island-like morphology. When inherently superhydrophilic TO coatings are converted to superhydrophobic, they remain non-wetting even after impingement with yttria-stabilized-zirconia particles, or exposure to ultraviolet light and extreme temperatures. Upon lubrication, these surfaces display omniphobicity against highly contaminating media retaining hitherto unseen mechanical durability. To illustrate the applicability of such a durable coating in biofouling conditions, we modified naval construction steels and surgical instruments and demonstrated significantly reduced marine algal film adhesion, Escherichia coli attachment and blood staining.

Combined biofouling and scaling in membrane feed channels: a new modeling approach.

PubMed

Radu, A I; Bergwerff, L; van Loosdrecht, M C M; Picioreanu, C

2015-01-01

A mathematical model was developed for combined fouling due to biofilms and mineral precipitates in membrane feed channels with spacers. Finite element simulation of flow and solute transport in two-dimensional geometries was coupled with a particle-based approach for the development of a composite (cells and crystals) foulant layer. Three fouling scenarios were compared: biofouling only, scaling only and combined fouling. Combined fouling causes a quicker flux decline than the summed flux deterioration when scaling and biofouling act independently. The model results indicate that the presence of biofilms leads to more mineral formation due to: (1) an enhanced degree of saturation for salts next to the membrane and within the biofilm; and (2) more available surface for nucleation to occur. The impact of biofilm in accelerating gypsum precipitation depends on the composition of the feed water (eg the presence of NaCl) and the kinetics of crystal nucleation and growth. Interactions between flow, solute transport and biofilm-induced mineralization are discussed.

In-situ biofouling of ocean thermal energy conversion (OTEC) evaporator tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasscer, D.S.; Morgan, T.

1981-05-01

The Puerto Rico Center for Energy and Environmental Research equipped a LCU facility in 1100 m of water near Punta Tuna, Puerto Rico to measure in situ biofouling of simulated Ocean Thermal Energy Conversion evaporator tubes. The system consisted of two 5052 aluminum alloy and two titanium tubes, through which a continuous flow of ocean water was maintained. The tubes were cleaned three times and the fouling resistance was measured, showing only slight differences between the tubes with respect to heat transfer loss resulting from biofouling. In all units, the average fouling rate after cleaning was greater than before cleaning,more » and only after the first cleaning did the aluminum units show greater fouling rates than did the titanium. The titanium units showed a progressive increase in the fouling rates with each cleaning. The subsequent average fouling rates for all units after eight months were between 4 and 4.6 x 0.000010 sq m-k/W-day.« less

Results of in-situ biofouling control, and corrosion test at Punta Tuna, Puerto Rico and its significance on OTEC heater exchanger design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasscer, D.S.; Morgan, T.O.; Tosteson, T.R.

1983-06-01

Because Ocean Thermal Energy Conversion (OTEC) operates at a low thermodynamic efficiency, heat exchangers represent a major portion of the overall cost of an OTEC power plant. For this reason, the commercial viability of OTEC depends on the design of efficient and inexpensive heat exchangers which have an operational life expectancy of 20 to 30 years and which can be maintained at a high level of efficiency by the use of effective biofouling control. Summarized here are the results of experiments conducted by the Center for Energy and Environment Research of the University of Puerto Rico to: determine the naturemore » of the biofilm which develops on heat exchanger surfaces exposed to running seawater, test the effectiveness of brush cleaning and chlorination in controlling biofouling on these surfaces and study the corrosion behavior of zinc protected aluminum alloys under OTEC conditions in an attempt to qualify them for use in low cost OTEC heat exchangers.« less

Light as a key driver of freshwater biofouling surface roughness in an experimental hydrocanal pipe rig.

PubMed

Ravizza, Matilde; Giosio, Dean; Henderson, Alan; Hovenden, Mark; Hudson, Monica; Salleh, Sazlina; Sargison, Jane; Shaw, Jennifer L; Walker, Jessica; Hallegraeff, Gustaaf

2016-07-01

Biofouling in canals and pipelines used for hydroelectric power generation decreases the flow capacity of conduits. A pipeline rig was designed consisting of test sections of varying substrata (PVC, painted steel) and light levels (transparent, frosted, opaque). Stalk-forming diatoms were abundant in both the frosted and transparent PVC pipes but negligible in the painted steel and opaque PVC pipes. Fungi were slightly more abundant in the painted steel pipe but equally present in all the other pipes while bacterial diversity was similar in all pipes. Photosynthetically functional biofouling (mainly diatoms) was able to develop in near darkness. Different biological fouling compositions generated differing friction factors. The highest friction factor was observed in the transparent pipe (densest diatom fouling), the lowest peak friction for the opaque PVC pipe (lowest fouling biomass), and with the painted steel pipe (high fouling biomass, but composed of fungal and bacterial crusts) being intermediate between the opaque and frosted PVC pipes.

Novel reverse osmosis membranes composed of modified PVA/Gum Arabic conjugates: Biofouling mitigation and chlorine resistance enhancement.

PubMed

Falath, Wail; Sabir, Aneela; Jacob, Karl I

2017-01-02

A novel crosslinked Poly (vinyl alcohol) (PVA) reverse osmosis (RO) thin film membrane conjugated with Gum Arabic (GA) with superb performance and features was synthesized for water desalination. RO membrane desalination parameters, such as hydrophilicity, surface roughness, water permeability, salt rejection, Chlorine resistance and biofouling resistance were evaluated using a dead end RO filtration unit. The incorporation of Pluronic F127 and the conjugation of Gum Arabic improved the overall RO performance of the membranes. This study has shown that the membrane PVA-GA-5 that contains 0.9wt% Gum Arabic provided excellent permeation, salt rejection, Chlorine and biofouling resistance and mechanical strength. The most remarkable result to arise from this research is that the overall RO performance enhancement has been achieved while utilizing PVA/Gum Arabic as a separation layer without the use of a substrate, which eliminates negative effects associated with the use of a substrate like internal concentration polarization. Copyright © 2016 Elsevier Ltd. All rights reserved.

Extremely durable biofouling-resistant metallic surfaces based on electrodeposited nanoporous tungstite films on steel

DOE PAGES

Tesler, Alexander B.; Kim, Philseok; Kolle, Stefan; ...

2015-10-20

Formation of unwanted deposits on steels during their interaction with liquids is an inherent problem that often leads to corrosion, biofouling and results in reduction in durability and function. Here we report a new route to form anti-fouling steel surfaces by electrodeposition of nanoporous tungsten oxide (TO) films. TO-modified steels are as mechanically durable as bare steel and highly tolerant to compressive and tensile stresses due to chemical bonding to the substrate and island-like morphology. When inherently superhydrophilic TO coatings are converted to superhydrophobic, they remain non-wetting even after impingement with yttria-stabilized-zirconia particles, or exposure to ultraviolet light and extrememore » temperatures. Upon lubrication, these surfaces display omniphobicity against highly contaminating media retaining hitherto unseen mechanical durability. Furthermore, to illustrate the applicability of such a durable coating in biofouling conditions, we modified naval construction steels and surgical instruments and demonstrated significantly reduced marine algal film adhesion, Escherichia coli attachment and blood staining.« less

The correlation between biofilm biopolymer composition and membrane fouling in submerged membrane bioreactors.

PubMed

Luo, Jinxue; Zhang, Jinsong; Tan, Xiaohui; McDougald, Diane; Zhuang, Guoqiang; Fane, Anthony G; Kjelleberg, Staffan; Cohen, Yehuda; Rice, Scott A

2014-10-01

Biofouling, the combined effect of microorganism and biopolymer accumulation, significantly reduces the process efficiency of membrane bioreactors (MBRs). Here, four biofilm components, alpha-polysaccharides, beta-polysaccharides, proteins and microorganisms, were quantified in MBRs. The biomass of each component was positively correlated with the transmembrane pressure increase in MBRs. Proteins were the most abundant biopolymer in biofilms and showed the fastest rate of increase. The spatial distribution and co-localization analysis of the biofouling components indicated at least 60% of the extracellular polysaccharide (EPS) components were associated with the microbial cells when the transmembrane pressure (TMP) entered the jump phase, suggesting that the EPS components were either secreted by the biofilm cells or that the deposition of these components facilitated biofilm formation. It is suggested that biofilm formation and the accumulation of EPS are intrinsically coupled, resulting in biofouling and loss of system performance. Therefore, strategies that control biofilm formation on membranes may result in a significant improvement of MBR performance.

Anti-biofouling property studies on carboxyl-modified multi-walled carbon nanotubes filled PDMS nanocomposites.

PubMed

Sun, Yuan; Zhang, Zhizhou

2016-09-01

Polydimethylsiloxane (PDMS) with exceptional fouling-release properties is extremely susceptible to the microfouling resulted from the colonization of the pioneer microorganisms in the marine environment. In this study, six carboxyl-modified multi-walled carbon nanotubes (cMWNTs) nanoparticles were incorporated into the PDMS matrix, respectively, in order to produce the cMWNTs-filled PDMS nanocomposites (CPs) with improved antifouling (AF) properties. The AF properties of the six CPs were examined via the field assays conducted in Weihai, China. The effects of the anti-biofouling potential of the CPs (i.e. the P3 surface) on the colonization of the pioneer prokaryotic and eukaryotic microbes were investigated using the single-stranded conformation polymorphism technique via the comparison of the diversity indices. Different CPs have displayed differential and better AF properties as compared to that of the unfilled PDMS (P0). The P3 surface has exhibited exceptional anti-biofouling capacity compared with the other CPs surfaces, which can effectively prevent biofouling for more than 14 weeks in the field. The SSCP analysis revealed that the P3 surface may have significant modulating effect on the pioneer microbial communities. The pioneer eukaryotic microbes seemed more susceptible than the pioneer prokaryotic microbes to be subjected to the major perturbations exerted by the P3 surface. The dramatically reduced eukaryotic-microbial diversity may contribute to the impeding and weakening of the development and growth of the biofilm. The P3 surface has the potential to be used for future maritime applications.

Improving sensitivity and specificity of capturing and detecting targeted cancer cells with anti-biofouling polymer coated magnetic iron oxide nanoparticles.

PubMed

Lin, Run; Li, Yuancheng; MacDonald, Tobey; Wu, Hui; Provenzale, James; Peng, Xingui; Huang, Jing; Wang, Liya; Wang, Andrew Y; Yang, Jianyong; Mao, Hui

2017-02-01

Detecting circulating tumor cells (CTCs) with high sensitivity and specificity is critical to management of metastatic cancers. Although immuno-magnetic technology for in vitro detection of CTCs has shown promising potential for clinical applications, the biofouling effect, i.e., non-specific adhesion of biomolecules and non-cancerous cells in complex biological samples to the surface of a device/probe, can reduce the sensitivity and specificity of cell detection. Reported herein is the application of anti-biofouling polyethylene glycol-block-allyl glycidyl ether copolymer (PEG-b-AGE) coated iron oxide nanoparticles (IONPs) to improve the separation of targeted tumor cells from aqueous phase in an external magnetic field. PEG-b-AGE coated IONPs conjugated with transferrin (Tf) exhibited significant anti-biofouling properties against non-specific protein adsorption and off-target cell uptake, thus substantially enhancing the ability to target and separate transferrin receptor (TfR) over-expressed D556 medulloblastoma cells. Tf conjugated PEG-b-AGE coated IONPs exhibited a high capture rate of targeted tumor cells (D556 medulloblastoma cell) in cell media (58.7±6.4%) when separating 100 targeted tumor cells from 1×10 5 non-targeted cells and 41 targeted tumor cells from 100 D556 medulloblastoma cells spiked into 1mL blood. It is demonstrated that developed nanoparticle has higher efficiency in capturing targeted cells than widely used micron-sized particles (i.e., Dynabeads ® ). Copyright © 2016 Elsevier B.V. All rights reserved.

Utilization of Copper Alloys for Marine Applications

NASA Astrophysics Data System (ADS)

Drach, Andrew

Utilization of copper alloy components in systems deployed in marine environment presents potential improvements by reducing maintenance costs, prolonging service life, and increasing reliability. However, integration of these materials faces technological challenges, which are discussed and addressed in this work, including characterization of material performance in seawater environment, hydrodynamics of copper alloy components, and design procedures for systems with copper alloys. To characterize the hydrodynamic behavior of copper alloy nets, mesh geometry of the major types of copper nets currently used in the marine aquaculture are analyzed and formulae for the solidity and strand length are proposed. Experimental studies of drag forces on copper alloy net panels are described. Based on these studies, empirical values for normal drag coefficients are proposed for various types of copper netting. These findings are compared to the previously published data on polymer nets. It is shown that copper nets exhibit significantly lower resistance to normal currents, which corresponds to lower values of normal drag coefficient. The seawater performance (corrosion and biofouling) of copper alloys is studied through the field trials of tensioned and untensioned specimens in a one-year deployment in the North Atlantic Ocean. The corrosion behavior is characterized by weight loss, optical microscopy, and SEM/EDX analyses. The biofouling performance is quantified in terms of the biomass accumulation. To estimate the effects of stray electrical currents on the seawater corrosion measurements, a low cost three-axis stray electric current monitoring device is designed and tested both in the lab and in the 30-day field deployment. The system consists of a remotely operated PC with a set of pseudo-electrodes and a digital compass. The collected data is processed to determine magnitudes of AC and DC components of electric field and dominant AC frequencies. Mechanical behavior of copper alloys is investigated through a series of uniaxial tension tests on virgin and weathered (after one-year deployment in the ocean) specimens. The changes in mechanical properties are quantified in terms of differences in Young's modulus, Poisson's ratio, ultimate strength, and ultimate strain. The obtained stress-strain data is used for numerical modeling of the mechanical behavior of chain-link nets. The simulations are compared with the experimental data on stiffness and strength of the nets. The available information on seawater performance of copper alloys (corrosion, biofouling, mechanics) and copper alloy nets (hydrodynamics) is used to develop engineering procedures for marine aquaculture fish cage systems with copper alloy netting. The design, analysis, and fabrication procedures are illustrated on a commercial size gravity-type offshore fish cage deployed in the Pacific Ocean near Isla Italia (Patagonia, Chile). The funding for this work was provided by the International Copper Association. This work was also supported through two UNH Fellowships: CEPS UNH Graduate Fellowship to Outstanding PhD Program Applicants and Dissertation Year Fellowship.

Antifouling strategies and corrosion control in cooling circuits.

PubMed

Cristiani, P; Perboni, G

2014-06-01

Biofouling and corrosion phenomena dramatically reduce the functionality of industrial cooling circuits, especially in marine environments. This study underlines the effectiveness of a low level chlorination treatment of seawater to prevent biological fouling and biocorrosion. Reported examples emphasize the reaction of chlorine with bromide, ammonia and organic compounds in seawater and the effectiveness of a treatment performed in such a way to guarantee a residual concentration lower than 3μM at the outlet of the condensers. In a brief review of antifouling strategies, alternatives to chlorination and the monitoring approach able to optimize the treatments are also reported. An integrated, on-line system based on electrochemical probes (Biox system and a linear polarization resistance probe) demonstrated to be sufficient to monitor in real time: corrosion, biofilm growth and chemical treatments based on chlorine or alternative oxidant products (chlorine dioxide, etc.). A careful electrochemical monitoring and the optimized treatments help the plant operators of industrial cooling circuits prevent the decay of the equipment performance, allowing at the same time the control of the halogenated by-products formation. Copyright © 2014 Elsevier B.V. All rights reserved.

Phosphorescent nanosensors for in vivo tracking of histamine levels.

PubMed

Cash, Kevin J; Clark, Heather A

2013-07-02

Continuously tracking bioanalytes in vivo will enable clinicians and researchers to profile normal physiology and monitor diseased states. Current in vivo monitoring system designs are limited by invasive implantation procedures and biofouling, limiting the utility of these tools for obtaining physiologic data. In this work, we demonstrate the first success in optically tracking histamine levels in vivo using a modular, injectable sensing platform based on diamine oxidase and a phosphorescent oxygen nanosensor. Our new approach increases the range of measurable analytes by combining an enzymatic recognition element with a reversible nanosensor capable of measuring the effects of enzymatic activity. We use these enzyme nanosensors (EnzNS) to monitor the in vivo histamine dynamics as the concentration rapidly increases and decreases due to administration and clearance. The EnzNS system measured kinetics that match those reported from ex vivo measurements. This work establishes a modular approach to in vivo nanosensor design for measuring a broad range of potential target analytes. Simply replacing the recognition enzyme, or both the enzyme and nanosensor, can produce a new sensor system capable of measuring a wide range of specific analytical targets in vivo.

Biofouling potential and material reactivity in a simulated water distribution network supplied with stormwater recycled via managed aquifer recharge.

PubMed

Gonzalez, Dennis; Tjandraatmadja, Grace; Barry, Karen; Vanderzalm, Joanne; Kaksonen, Anna H; Dillon, Peter; Puzon, Geoff J; Sidhu, Jatinder; Wylie, Jason; Goodman, Nigel; Low, Jason

2016-11-15

The injection of stormwater into aquifers for storage and recovery during high water demand periods is a promising technology for augmenting conventional water reserves. Limited information exists regarding the potential impact of aquifer treated stormwater in distribution system infrastructure. This study describes a one year pilot distribution pipe network trial to determine the biofouling potential for cement, copper and polyvinyl chloride pipe materials exposed to stormwater stored in a limestone aquifer compared to an identical drinking water rig. Median alkalinity (123 mg/L) and colour (12 HU) in stormwater was significantly higher than in drinking water (82 mg/L and 1 HU) and pipe discolouration was more evident for stormwater samples. X-ray Diffraction and Fluorescence analyses confirmed this was driven by the presence of iron rich amorphous compounds in more thickly deposited sediments also consistent with significantly higher median levels of iron (∼0.56 mg/L) in stormwater compared to drinking water (∼0.17 mg/L). Water type did not influence biofilm development as determined by microbial density but faecal indicators were significantly higher for polyvinyl chloride and cement exposed to stormwater. Treatment to remove iron through aeration and filtration would reduce the potential for sediment accumulation. Operational and verification monitoring parameters to manage scaling, corrosion, colour, turbidity and microbial growth in recycled stormwater distribution networks are discussed. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Effect of water temperature on biofouling development in reverse osmosis membrane systems.

PubMed

Farhat, N M; Vrouwenvelder, J S; Van Loosdrecht, M C M; Bucs, Sz S; Staal, M

2016-10-15

Understanding the factors that determine the spatial and temporal biofilm development is a key to formulate effective control strategies in reverse osmosis membrane systems for desalination and wastewater reuse. In this study, biofilm development was investigated at different water temperatures (10, 20, and 30 °C) inside a membrane fouling simulator (MFS) flow cell. The MFS studies were done at the same crossflow velocity with the same type of membrane and spacer materials, and the same feed water type and nutrient concentration, differing only in water temperature. Spatially resolved biofilm parameters such as oxygen decrease rate, biovolume, biofilm spatial distribution, thickness and composition were measured using in-situ imaging techniques. Pressure drop (PD) increase in time was used as a benchmark as to when to stop the experiments. Biofilm measurements were performed daily, and experiments were stopped once the average PD increased to 40 mbar/cm. The results of the biofouling study showed that with increasing feed water temperature (i) the biofilm activity developed faster, (ii) the pressure drop increased faster, while (iii) the biofilm thickness decreased. At an average pressure drop increase of 40 mbar/cm over the MFS for the different feed water temperatures, different biofilm activities, structures, and quantities were found, indicating that diagnosis of biofouling of membranes operated at different or varying (seasonal) feed water temperatures may be challenging. Membrane installations with a high temperature feed water are more susceptible to biofouling than installations fed with low temperature feed water. Copyright © 2016 Elsevier Ltd. All rights reserved.

A biomimetic nano hybrid coating based on the lotus effect and its anti-biofouling behaviors

NASA Astrophysics Data System (ADS)

Li, Jiang; Wang, Guoqing; Meng, Qinghua; Ding, Chunhua; Jiang, Hong; Fang, Yongzeng

2014-10-01

To develop an environmentally friendly anti-biofouling coating in virtue of bionics, a block copolymer containing fluorine (Coplm_F) of low surface energy was prepared by copolymerization. The Ag-loaded mesoporous silica (Ag@SBA) acting as a controlled-release antifoulant was prepared from the mesoporous silica (SBA-15). The nano hybrid coating (Ag@SBA/Coplm_F) composing of the Coplm_F and Ag@SBA was to biomimetically simulate the lotus microstructure. The concentration of fluorine element on surface was analyzed by the energy dispersive spectroscopy (EDS) and found rising to 1.45% after hybridation, which could be explained by the driving effect of SBA-15 via the hydrogen bond. This nanoscale morphology of the hybrid coating was measured and found highly semblable to the microstructure of the lotus surface. The contact angle was determined as 151° which confirmed the superhydrophobicity and lotus effect. The adhesion behaviors of Pseudomonas fluorescens, Diatoms, and Chlorella on the surface of the nano hybrid coating (Ag@SBA/Coplm_F) were studied and good effects of anti-biofouling were observed.

Triclosan-immobilized polyamide thin film composite membranes with enhanced biofouling resistance

NASA Astrophysics Data System (ADS)

Park, Sang-Hee; Hwang, Seon Oh; Kim, Taek-Seung; Cho, Arah; Kwon, Soon Jin; Kim, Kyoung Taek; Park, Hee-Deung; Lee, Jung-Hyun

2018-06-01

We report on a strategy to improve biofouling resistance of a polyamide (PA) thin-film composite (TFC) reverse osmosis (RO) membrane via chemically immobilizing triclosan (TC), known as a common organic biocide, on its surface. To facilitate covalent attachment of TC on the membrane surface, TC was functionalized with amine moiety to prepare aminopropyl TC. Then, the TC-immobilized TFC (TFC-TC) membranes were fabricated through a one-step amide formation reaction between amine groups of aminopropyl TC and acyl chloride groups present on the PA membrane surface, which was confirmed by high-resolution XPS. Strong stability of the immobilized TC was also confirmed by a hydraulic washing test. Although the TFC-TC membrane showed slightly reduced separation performance compared to the pristine control, it still maintained a satisfactory RO performance level. Importantly, the TFC-TC membrane exhibited excellent antibacterial activity against both gram negative (E. coli and P. aeruginosa) and gram positive (S. aureus) bacteria along with greatly enhanced resistance to biofilm formation. Our immobilization approach offers a robust and relatively benign strategy to control biofouling of functional surfaces, films and membranes.

Isolation and metagenomic characterization of bacteria associated with calcium carbonate and struvite precipitation in a pure moving bed biofilm reactor-membrane bioreactor.

PubMed

Gonzalez-Martinez, A; Leyva-Díaz, J C; Rodriguez-Sanchez, A; Muñoz-Palazon, B; Rivadeneyra, A; Poyatos, J M; Rivadeneyra, M A; Martinez-Toledo, M V

2015-01-01

A bench-scale pure moving bed bioreactor-membrane bioreactor (MBBR-MBR) used for the treatment of urban wastewater was analyzed for the identification of bacterial strains with the potential capacity for calcium carbonate and struvite biomineral formation. Isolation of mineral-forming strains on calcium carbonate and struvite media revealed six major colonies with a carbonate or struvite precipitation capacity in the biofouling on the membrane surface and showed that heterotrophic bacteria with the ability to precipitate calcium carbonate and struvite constituted ~7.5% of the total platable bacteria. These belonged to the genera Lysinibacillus, Trichococcus, Comamomas and Bacillus. Pyrosequencing analysis of the microbial communities in the suspended cells and membrane biofouling showed a high degree of similarity in all the samples collected with respect to bacterial assemblage. The study of operational taxonomic units (OTUs) identified through pyrosequencing suggested that ~21% of the total bacterial community identified in the biofouling could potentially form calcium carbonate or struvite crystals in the pure MBBR-MBR system used for the treatment of urban wastewater.

Chitosan-zinc oxide nanocomposite coatings for the prevention of marine biofouling.

PubMed

Al-Naamani, Laila; Dobretsov, Sergey; Dutta, Joydeep; Burgess, J Grant

2017-02-01

Marine biofouling is a worldwide problem affecting maritime industries. Global concerns about the high toxicity of antifouling paints have highlighted the need to develop less toxic antifouling coatings. Chitosan is a natural polymer with antimicrobial, antifungal and antialgal properties that is obtained from partial deacetylation of crustacean waste. In the present study, nanocomposite chitosan-zinc oxide (chitosan-ZnO) nanoparticle hybrid coatings were developed and their antifouling activity was tested. Chitosan-ZnO nanoparticle coatings showed anti-diatom activity against Navicula sp. and antibacterial activity against the marine bacterium Pseudoalteromonas nigrifaciens. Additional antifouling properties of the coatings were investigated in a mesocosm study using tanks containing natural sea water under controlled laboratory conditions. Each week for four weeks, biofilm was removed and analysed by flow cytometry to estimate total bacterial densities on the coated substrates. Chitosan-ZnO hybrid coatings led to better inhibition of bacterial growth in comparison to chitosan coatings alone, as determined by flow cytometry. This study demonstrates the antifouling potential of chitosan-ZnO nanocomposite hybrid coatings, which can be used for the prevention of biofouling. Copyright © 2016 Elsevier Ltd. All rights reserved.

Super-hydrophobicity fundamentals: implications to biofouling prevention.

PubMed

Marmur, Abraham

2006-01-01

The theory of wetting on super-hydrophobic surfaces is presented and discussed, within the general framework of equilibrium wetting and contact angles. Emphasis is put on the implications of super-hydrophobicity to the prevention of biofouling. Two main lines of thought are discussed, viz. i) "mirror imaging" of the Lotus effect, namely designing a surface that repels biological entities by being super-hydrophilic, and ii) designing a surface that minimises the water-wetted area when submerged in water (by keeping an air film between the water and the surface), so that the suspended biological entities have a low probability of encountering the solid surface.

Degradation of common polymer ropes in a sublittoral marine environment.

PubMed

Welden, Natalie A; Cowie, Phillip R

2017-05-15

Contamination by microplastic particles and fibres has been observed in sediment and animals sampled from the Firth of Clyde, West Scotland. In addition to microplastics released during clothes washing, a probable source is polymer ropes in abandoned, lost and discarded fishing and recreational sailing gear. The fragmentation of polypropylene, polyethylene, and nylon exposed to benthic conditions at 10m depth over 12months was monitored using changes in weight and tensile properties. Water temperature and light levels were continuously monitored. The degree of biofouling was measured using chlorophyll a, the weight of attached macroalgae, and colonising fauna. Results indicate microplastic fibres and particles may be formed in benthic environments despite reduced photodegradation. Polypropylene, Nylon, and polyethylene lost an average of 0.39%, 1.02%, and 0.45% of their mass per month respectively. Microscope images of the rope surface revealed notable surface roughening believed to be caused by abrasion by substrate and the action of fouling organisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microbial Monitoring of the International Space Station

NASA Technical Reports Server (NTRS)

Pierson, Duane L.; Botkin, Douglas J.; Bruce, Rebekah J.; Castro, Victoria A.; Smith, Melanie J.; Oubre, Cherie M.; Ott, C. Mark

2013-01-01

Humans living and working in the harsh environment of space present many challenges for habitability engineers and microbiologists. Spacecraft must provide an internal environment in which physical (gas composition, pressure, temperature, and humidity), chemical, and biological environmental parameters are maintained at safe levels. Microorganisms are ubiquitous and will accompany all human-occupied spacecraft, but if biological contamination were to reach unacceptable levels, long-term human space flight would be impossible. Prevention of microbiological problems, therefore, must have a high priority. Historically, prevention of infectious disease in the crew has been the highest priority, but experience gained from the NASA-Mir program showed that microbial contamination of vehicle and life-support systems, such as biofouling of water and food, are of equal importance. The major sources of microbiological risk factors for astronauts include food, drinking water, air, surfaces, payloads, research animals, crew members, and personnel in close contact with the astronauts. In our efforts to eliminate or mitigate the negative effects of microorganisms in spacecraft, the National Aeronautics and Space Administration (NASA) implemented comprehensive microbial analyses of the major risk factors. This included the establishment of acceptability requirements for food, water, air, surfaces, and crew members. A robust monitoring program was then implemented to verify that the risks were within acceptable limits. Prevention of microbiological problems is preferred over mitigation of problems during flight, and preventive steps must begin very early in the design phase. Spacecraft development must include requirements to control free water from humidity, condensate, hygiene activities, and other releases. If water is available, microbes are likely to grow because sufficient nutrients are potentially available. Materials selected for the spacecraft must not promote or support microbial growth. Air filtration can dramatically reduce the number of airborne bacteria, fungi, and particulates in spacecraft breathing air. Waterborne bacteria can be reduced to acceptable levels by thermal inactivation of bacteria during water processing, along with a residual biocide, and filtration at the point of use can ensure safety. System design must include onboard capability to achieve recovery of the system from contamination. Robust housekeeping procedures that include periodic cleaning and disinfection will prevent high levels of microbial growth on surfaces. Food for consumption in space must be thoroughly tested for excessive microbial content and pathogens before launch. Thorough preflight examination of flight crews, consumables, payloads, and the environment can greatly reduce pathogens in spacecraft. Many of the lessons learned from the Space Shuttle and previous programs were applied in the early design phase of the International Space Station, resulting in the safest space habitat to date. This presentation describes the monitoring program for the International Space Station and will summarize results from preflight and on-orbit monitoring.

Testing animal-assisted cleaning prior to transplantation in coral reef restoration.

PubMed

Frias-Torres, Sarah; van de Geer, Casper

2015-01-01

Rearing coral fragments in nurseries and subsequent transplantation onto a degraded reef is a common approach for coral reef restoration. However, if barnacles and other biofouling organisms are not removed prior to transplantation, fish will dislodge newly cemented corals when feeding on biofouling organisms. This behavior can lead to an increase in diver time due to the need to reattach the corals. Thus, cleaning nurseries to remove biofouling organisms such as algae and invertebrates is necessary prior to transplantation, and this cleaning constitutes a significant time investment in a restoration project. We tested a novel biomimicry technique of animal-assisted cleaning on nursery corals prior to transplantation at a coral reef restoration site in Seychelles, Indian Ocean. To determine whether animal-assisted cleaning was possible, preliminary visual underwater surveys were performed to quantify the fish community at the study site. Then, cleaning stations consisting of nursery ropes carrying corals and biofouling organisms, set at 0.3 m, 2 m, 4 m, 6 m and 8 m from the seabed, were placed at both the transplantation (treatment) site and the nursery (control) site. Remote GoPro video cameras recorded fish feeding at the nursery ropes without human disturbance. A reef fish assemblage of 32 species from 4 trophic levels (18.8% herbivores, 18.8% omnivores, 59.3% secondary consumers and 3.1% carnivores) consumed 95% of the barnacles on the coral nursery ropes placed 0.3 m above the seabed. Using this cleaning station, we reduced coral dislodgement from 16% to zero. This cleaning station technique could be included as a step prior to coral transplantation worldwide on the basis of location-specific fish assemblages and during the early nursery phase of sexually produced juvenile corals.

Testing animal-assisted cleaning prior to transplantation in coral reef restoration

PubMed Central

van de Geer, Casper

2015-01-01

Rearing coral fragments in nurseries and subsequent transplantation onto a degraded reef is a common approach for coral reef restoration. However, if barnacles and other biofouling organisms are not removed prior to transplantation, fish will dislodge newly cemented corals when feeding on biofouling organisms. This behavior can lead to an increase in diver time due to the need to reattach the corals. Thus, cleaning nurseries to remove biofouling organisms such as algae and invertebrates is necessary prior to transplantation, and this cleaning constitutes a significant time investment in a restoration project. We tested a novel biomimicry technique of animal-assisted cleaning on nursery corals prior to transplantation at a coral reef restoration site in Seychelles, Indian Ocean. To determine whether animal-assisted cleaning was possible, preliminary visual underwater surveys were performed to quantify the fish community at the study site. Then, cleaning stations consisting of nursery ropes carrying corals and biofouling organisms, set at 0.3 m, 2 m, 4 m, 6 m and 8 m from the seabed, were placed at both the transplantation (treatment) site and the nursery (control) site. Remote GoPro video cameras recorded fish feeding at the nursery ropes without human disturbance. A reef fish assemblage of 32 species from 4 trophic levels (18.8% herbivores, 18.8% omnivores, 59.3% secondary consumers and 3.1% carnivores) consumed 95% of the barnacles on the coral nursery ropes placed 0.3 m above the seabed. Using this cleaning station, we reduced coral dislodgement from 16% to zero. This cleaning station technique could be included as a step prior to coral transplantation worldwide on the basis of location-specific fish assemblages and during the early nursery phase of sexually produced juvenile corals. PMID:26468440

Modelling of the impact of biofouling on hydrodynamics downstream of a tidal turbine

NASA Astrophysics Data System (ADS)

Bennis, A. C.; Rivier, A.; Dauvin, J. C.

2016-02-01

Biological organisms, like barnacles, mussels or bryozoans, colonize rapidly an immersed surface and could form a thickness until several centimeters on it. This biofouling could modify hydrodynamics around tidal turbine by increasing drag and hence resistance and could be detrimental to the performance of turbine (e.g. Orme et al., 2001; Khor and Xiao, 2011). Our work focuses on modifications of vortices downstream of a tidal turbine due to biofouling using CFD. Fixed biological organisms are solved explicitly by the model and are considered by modifying the blade profile. Firstly an airfoil colonized by barnacles is modelled for various fouling height and spacing and results are compared to experimental and simulated data (Orme et al., 2001; Khor and Xiao, 2011) in order to assess the capacity of the model to reproduce the flow around a blade with biofouling. Then a Darrieus vertical axis tidal turbine is modelled using a dynamic mesh. Configuration with smooth clean blades is assessed by comparison with experiments and simulations made by Roa (2011) and Bossard (2012). Biological organisms with various heights, spacing and shapes are fixed on blades and wakes downstream of clean and colonized tidal turbine are compared. Vorticity fields around the tidal turbine are clearly modified when blades are colonized. Samples will be taken from location where farms are planned to be built (Alderney Race/Raz Blanchard) to characterize more precisely the characteristics of species which are liable to fix on tidal turbine.Reference:Bossard (2012). Doctoral dissertation, Université de Grenoble.Khor & Xiao. (2011). Ocean Eng, 38(10), 1065-1079. Orme et al. (2001). Marine Renewable Energy Conference, Newcastle.Roa (2011).Doctoral dissertation, Université de Grenoble.

Isolation of marine fungi Aspergillus sp. and its in vitro antifouling activity against marine bacteria.

PubMed

Thiyagarajan, Santhananmari; Bavya, Manoharan; Jamal, Alruwaili

2016-09-01

Biofouling is considered as a main issue of concern in aquatic environment causing severe economic loss and pollution. The aim of the present study was to isolate marine fungus antagonistic to biofouling bacteria and to define antifouling compounds present in it. Using standard plate method five predominant biofouling bacteria viz., Methylococcus sp., Flavobacterium sp., Marinococcus sp., Serratia sp. and Pseudomonas sp. were isolated from marine solid substances on Zobell's agar. Tolerance range of these bacteria to NaCl was 2-10%. Isolation of fungi from mangrove and estuarine sediments and their screening identified Aspergillus sp. EF4 as a potential isolate. This isolate caused inhibition of all the five test bacterial cultures measuring zone diameters respectively of 11, 16, 12, 13 and 11mm.? Subsequent to submerged fermentation using shaking flask method this fungus produced bioactive compounds within 5 days. The culture parameters optimized were raffinose as carbon source, yeast extract as lone nitrogen source, pH up to 9.0 and temperature up to 40?C. Antifouling compounds of culture filtrate were separated and detected by a three-step procedure involving thin layer chromatography, bioautography and preparative TLC. The in vitro assay involving glass slide-wooden stick-biofilm method revealed that these compounds could cause inhibition and destruction of bacteria to an extent of 2.16 x 104 CFU ml-1 and 2.46 x 104 CFU ml-1 respectively while growth of bacteria in control beaker was enumerated to be 4.41 x 104 CFU ml-1. High performance liquid chromatography of culture filtrate indicated probable principal antifouling compound as Fumonisin B2. Isolation of antagonistic marine fungus from Indian coast and detection of its antifouling compound would help in planning effective strategies for controlling biofouling in marine environment.

Ups and Downs in the Ocean: Effects of Biofouling on Vertical Transport of Microplastics.

PubMed

Kooi, Merel; Nes, Egbert H van; Scheffer, Marten; Koelmans, Albert A

2017-07-18

Recent studies suggest size-selective removal of small plastic particles from the ocean surface, an observation that remains unexplained. We studied one of the hypotheses regarding this size-selective removal: the formation of a biofilm on the microplastics (biofouling). We developed the first theoretical model that is capable of simulating the effect of biofouling on the fate of microplastic. The model is based on settling, biofilm growth, and ocean depth profiles for light, water density, temperature, salinity, and viscosity. Using realistic parameters, the model simulates the vertical transport of small microplastic particles over time, and predicts that the particles either float, sink to the ocean floor, or oscillate vertically, depending on the size and density of the particle. The predicted size-dependent vertical movement of microplastic particles results in a maximum concentration at intermediate depths. Consequently, relatively low abundances of small particles are predicted at the ocean surface, while at the same time these small particles may never reach the ocean floor. Our results hint at the fate of "lost" plastic in the ocean, and provide a start for predicting risks of exposure to microplastics for potentially vulnerable species living at these depths.

Natural cleaning of the black-lip pearl oyster Pinctada margaritifera by butterflyfishes (Chaetodon) in French Polynesia

NASA Astrophysics Data System (ADS)

Bertucci, Frédéric; Legraverant, Yohann; Berthe, Cécile; Brooker, Rohan M.; Lo, Cédrik; Lecchini, David

2016-12-01

Biofouling increases the operational and economic costs associated with pearl production. As current procedures for reducing oyster biofouling can be detrimental to survival and growth and may pollute the surrounding environment developing alternative, biologically-mediated, methods could potentially increase both production and ecological sustainability. With this in mind, the present study investigated natural cleaning of black-lipped pearl oysters, Pinctada margaritifera, by butterflyfishes (Chaetodon). The feeding behaviour of six butterflyfish species was examined at Rangiroa Atoll, French Polynesia: Chaetodon auriga, Chaetodon citrinellus, Chaetodon ephippium, Chaetodon lunulatus, Chaetodon trifascialis and Chaetodon ulietensis. All species cleaned the surface of pearl oysters by removing epibionts (from 16% to 40% of total biomass), although dietary variation may explain different cleaning efficiencies. Generalist omnivores (C. auriga, C. citrinellus, C. ephippium and C. ulietensis) were the most efficient cleaners (% cleaning range: 26-40% of total biomass). Within this group, C. ephippium removed the most biomass (average of 41%) targeting algae and anemones. However, C. auriga targeted the most diverse range of epibionts, removing significant amounts of algae, sponges, tunicates, and anemones. These results suggest that foraging by butterflyfishes can substantially reduce biofouling on economically-important tropical bivalves.

Anti-biofouling 3D porous systems: the blend effect of oxazoline-based oligomers on chitosan scaffolds.

PubMed

Correia, Vanessa G; Coelho, Margarida; Barroso, Telma; Raje, Vivek P; Bonifácio, Vasco D B; Casimiro, Teresa; Pinho, Mariana G; Aguiar-Ricardo, Ana

2013-01-01

The production, characterization and anti-biofouling activity of 3D porous scaffolds combining different blends of chitosan and oxazoline-based antimicrobial oligomers is reported. The incorporation of ammonium quaternized oligo(2-oxazoline)s into the composition of the scaffold enhances the stability of the chitosan scaffold under physiological conditions as well as its ability to repel protein adsorption. The blended scaffolds showed mean pore sizes in the range of 18-32 μm, a good pore interconnectivity and high porosity, as well as a large surface area, ultimate key features for anti-biofouling applications. Bovine serum albumin (BSA) adhesion profiles showed that the composition of the scaffolds plays a critical role in the chitosan-oligooxazoline system. Oligobisoxazoline-enriched scaffolds (20% w/w, CB8020) decreased protein adsorption (BSA) by up to 70%. Moreover, 1 mg of CB8020 was able to kill 99.9% of Escherichia coli cells upon contact, demonstrating its potential as promising material for production of tailored non-fouling 3D structures to be used in the construction of novel devices with applications in the biomedical field and water treatment processes.

Biological control of biofilms on membranes by metazoans.

PubMed

Klein, Theresa; Zihlmann, David; Derlon, Nicolas; Isaacson, Carl; Szivak, Ilona; Weissbrodt, David G; Pronk, Wouter

2016-01-01

Traditionally, chemical and physical methods have been used to control biofouling on membranes by inactivating and removing the biofouling layer. Alternatively, the permeability can be increased using biological methods while accepting the presence of the biofouling layer. We have investigated two different types of metazoans for this purpose, the oligochaete Aelosoma hemprichi and the nematode Plectus aquatilis. The addition of these grazing metazoans in biofilm-controlled membrane systems resulted in a flux increase of 50% in presence of the oligochaetes (Aelosoma hemprichi), and a flux increase of 119-164% in presence of the nematodes (Plectus aquatilis) in comparison to the control system operated without metazoans. The change in flux resulted from (1) a change in the biofilm structure, from a homogeneous, cake-like biofilm to a more heterogeneous, porous structure and (2) a significant reduction in the thickness of the basal layer. Pyrosequencing data showed that due to the addition of the predators, also the community composition of the biofilm in terms of protists and bacteria was strongly affected. The results have implications for a range of membrane processes, including ultrafiltration for potable water production, membrane bioreactors and reverse osmosis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Potency of Nicotiana tabacum as anti - microfouling

NASA Astrophysics Data System (ADS)

Aunurohim, Nurilma, Dian Ahmada; Kuswytasari, Nengah Dwianita

2017-06-01

In general, the attachment and growth of organisms on the surface of the object or material immersed in the sea are called Biofouling. Biofouling microscopic called microfouling, where it acts as a precursor of the next engaging organisms that are generally larger in size (called macrofouling). In recent time, biofouling control over the use of chemicals in antifouling paints. Usage tributyltin polishing copolymer paints (TBT - SPC paint) containing TBT has adverse effects on non-target marine organisms. This study uses tobacco dust as an anti-microfouling, which is the waste generated during the process of tobacco leaves. Five of bacterial isolates have been founded at Surabaya coastal in a preliminary test with iron plates. Then those isolates tested to detect and visualized of biofilm. The activity of anti-bacteria had been done and the result is known that more high of tobacco extract given, a diameter of zone inhibit high too. The extract of tobacco dust can be applied most effectively to be anti-microfouling is a concentration of 40%, isolates 3 and 4 are a type of bacteria that is most inhibited growth. So, in this result, Nicotiana tabacum is potential as an anti-microfouling.

The roles of bacteriophages in membrane-based water and wastewater treatment processes: A review.

PubMed

Wu, Bing; Wang, Rong; Fane, Anthony G

2017-03-01

Membrane filtration processes have been widely applied in water and wastewater treatment for many decades. Concerns related to membrane treatment effectiveness, membrane lifespan, and membrane fouling control have been paid great attention. To achieve sustainable membrane operation with regards to low energy and maintenance cost, monitoring membrane performance and applying suitable membrane control strategies are required. As the most abundant species in water and wastewater, bacteriophages have shown great potential to be employed in membrane processes as (1) indicators to assess membrane performance considering their similar properties to human pathogenic waterborne viruses; (2) surrogate particles to monitor membrane integrity due to their nano-sized nature; and (3) biological agents to alleviate membrane fouling because of their antimicrobial properties. This study aims to provide a comprehensive review on the roles of bacteriophages in membrane-based water and wastewater treatment processes, with focuses on their uses for membrane performance examination, membrane integrity monitoring, and membrane biofouling control. The advantages, limitations, and influencing factors for bacteriophage-based applications are reported. Finally, the challenges and prospects of bacteriophage-based applications in membrane processes for water treatment are highlighted. Copyright © 2016 Elsevier Ltd. All rights reserved.

Which Members of the Microbial Communities Are Active? Microarrays

NASA Astrophysics Data System (ADS)

Morris, Brandon E. L.

Here, we introduce the concept of microarrays, discuss the advantages of several different types of arrays and present a case study that illustrates a targeted-profiling approach to bioremediation of a hydrocarbon-contaminated site in an Arctic environment. The majority of microorganisms in the terrestrial subsurface, particularly those involved in 'heavy oil' formation, reservoir souring or biofouling remain largely uncharacterised (Handelsman, 2004). There is evidence though that these processes are biologically catalysed, including stable isotopic composition of hydrocarbons in oil formations (Pallasser, 2000; Sun et al., 2005), the absence of biodegraded oil from reservoirs warmer than 80°C (Head et al., 2003) or negligible biofouling in the absence of biofilms (Dobretsov et al., 2009; Lewandowski and Beyenal, 2008), and all clearly suggest an important role for microorganisms in the deep biosphere in general and oilfield systems in particular. While the presence of sulphate-reducing bacteria in oilfields was first observed in the early twentieth century (Bastin, 1926), it was only through careful experiments with isolates from oil systems or contaminated environments that unequivocal evidence for hydrocarbon biodegradation under anaerobic conditions was provided (for a review, see Widdel et al., 2006). Work with pure cultures and microbial enrichments also led to the elucidation of the biochemistry of anaerobic aliphatic and aromatic hydrocarbon degradation and the identification of central metabolites and genes involved in the process, e.g. (Callaghan et al., 2008; Griebler et al., 2003; Kropp et al., 2000). This information could then be extrapolated to the environment to monitor degradation processes and determine if in situ microbial populations possessed the potential for contaminant bioremediation, e.g. Parisi et al. (2009). While other methods have also been developed to monitor natural attenuation of hydrocarbons (Meckenstock et al., 2004), we are only at the early stages of understanding the microbial processes that occur in petroliferous formations and the surrounding subterranean environment. Important first steps in characterising the microbiology of oilfield systems involve identifying the microbial community structure and determining how population diversity changes are affected by the overall geochemical and biological parameters of the system. This is relatively easy to do today by using general 16S rRNA primers for PCR and building clone libraries. For example, previous studies using molecular methods characterised many dominant prokaryotes in petroleum reservoirs (Orphan et al., 2000) and in two Alaskan North Slope oil facilities (Duncan et al., 2009; Pham et al., 2009). However, the problem is that more traditional molecular biology approaches, such as 16S clone libraries, fail to detect large portions of the community perhaps missing up to half of the biodiversity (see Hong et al., 2009) and require significant laboratory time to construct large libraries necessary to increase the probability of detecting the majority of even bacterial biodiversity. In the energy sector, the overarching desire would be to quickly assess the extent of in situ hydrocarbon biodegradation or to disrupt detrimental processes such as biofouling, and in these cases it may not be necessary to identify specific microbial species. Rather, it would be more critical to evaluate metabolic processes or monitor gene products that are implicated in the specific activity of interest. Research goals such as these are well suited for a tailored application of microarray technology.

Biofouling of contaminated ground-water recovery wells: Characterization of microorganisms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, S.W.; Lange, C.R.; Lesold, E.A.

1997-11-01

The taxonomy and physiology of microorganisms isolated from contaminated ground-water recovery wells prone to biofouling are characterized for an industrial site in Rochester, New York. Principal aquifer contaminants include acetone, cyclohexane, dichloroethane, dichloromethane, 1,4-dioxane, isopropanol, methanol, and toluene. These contaminants represent a significant fraction (up to 95%) of the total organic carbon in the ground water. Ground-water samples from 12 recovery wells were used to isolate, quantify, and identify aerobic and anaerobic bacterial populations. Samples from selected wells were also characterized geochemically to assess redox conditions and availability of essential and trace nutrients. Dominant bacteria, listed in order of descendingmore » numbers, including sulfate-reducers (Desulfovibrio desulfuricans), anaerobic heterotrophs (Actinomyces, Bacteriodes, Bacillus, Agrobacterium), aerobic heterotrophs (Pseudomonas, Flavobacterium, Nocardia, Citrobacter), iron-oxidizers (Gallionella ferruginea, Crenothrix polyspora), iron-reducers (Shewanella), and sulfur-oxidizers (Thiobacillus ferrooxidans). Fungi were also recovered in low numbers. Both aerobic and anaerobic heterotrophs were able to utilize all principal contaminants as sole carbon and energy sources except 1,4-dioxane. The prevalence of heterotrophic bacteria and their ability to use the available anthropogenic carbon suggests that aerobic and anaerobic heterotrophs contribute to the biofouling of wells at this site, in addition to the often cited fouling due to iron-oxidizing bacteria and sulfate-reducing bacteria.« less

Mitigation of Membrane Biofouling in MBR Using a Cellulolytic Bacterium, Undibacterium sp. DM-1, Isolated from Activated Sludge.

PubMed

Nahm, Chang Hyun; Lee, Seonki; Lee, Sang Hyun; Lee, Kibaek; Lee, Jaewoo; Kwon, Hyeokpil; Choo, Kwang-Ho; Lee, Jung-Kee; Jang, Jae Young; Lee, Chung-Hak; Park, Pyung-Kyu

2017-03-28

Biofilm formation on the membrane surface results in the loss of permeability in membrane bioreactors (MBRs) for wastewater treatment. Studies have revealed that cellulose is not only produced by a number of bacterial species but also plays a key role during formation of their biofilm. Hence, in this study, cellulase was introduced to a MBR as a cellulose-induced biofilm control strategy. For practical application of cellulase to MBR, a cellulolytic ( i.e ., cellulase-producing) bacterium, Undibacterium sp. DM-1, was isolated from a lab-scale MBR for wastewater treatment. Prior to its application to MBR, it was confirmed that the cell-free supernatant of DM-1 was capable of inhibiting biofilm formation and of detaching the mature biofilm of activated sludge and cellulose-producing bacteria. This suggested that cellulase could be an effective anti-biofouling agent for MBRs used in wastewater treatment. Undibacterium sp. DM-1-entrapping beads ( i.e ., cellulolytic-beads) were applied to a continuous MBR to mitigate membrane biofouling 2.2-fold, compared with an MBR with vacant-beads as a control. Subsequent analysis of the cellulose content in the biofilm formed on the membrane surface revealed that this mitigation was associated with an approximately 30% reduction in cellulose by cellulolytic-beads in MBR.

A Tuneable Switch for Controlling Environmental Degradation of Bioplastics: Addition of Isothiazolinone to Polyhydroxyalkanoates

PubMed Central

Woolnough, Catherine Anne; Yee, Lachlan Hartley; Charlton, Timothy Stuart; Foster, Leslie John Ray

2013-01-01

Controlling the environmental degradation of polyhydroxybutyrate (PHB) and polyhydroxyvalerate (P(HB-co-HV)) bioplastics would expand the range of their potential applications. Combining PHB and P(HB-co-HV) films with the anti-fouling agent 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOI, <10% w/w) restricted microbial colonisation in soil, but did not significantly affect melting temperature or the tensile strength of films. DCOI films showed reduced biofouling and postponed the onset of weight loss by up to 100 days, a 10-fold increase compared to unmodified films where the microbial coverage was significant. In addition, the rate of PHA-DCOI weight loss, post-onset, reduced by about 150%; in contrast a recorded weight loss of only 0.05% per day for P(HB-co-HV) with a 10% DCOI loading was observed. This is in stark contrast to the unmodified PHB film, where a recorded weight loss of only 0.75% per day was made. The ‘switch’ that initiates film weight loss, and its subsequent reduced rate, depended on the DCOI loading to control biofouling. The control of biofouling and environmental degradation for these DCOI modified bioplastics increases their potential use in biodegradable applications. PMID:24146779

In situ spectrophotometric measurement of dissolved inorganic carbon in seawater.

PubMed

Liu, Xuewu; Byrne, Robert H; Adornato, Lori; Yates, Kimberly K; Kaltenbacher, Eric; Ding, Xiaoling; Yang, Bo

2013-10-01

Autonomous in situ sensors are needed to document the effects of today's rapid ocean uptake of atmospheric carbon dioxide (e.g., ocean acidification). General environmental conditions (e.g., biofouling, turbidity) and carbon-specific conditions (e.g., wide diel variations) present significant challenges to acquiring long-term measurements of dissolved inorganic carbon (DIC) with satisfactory accuracy and resolution. SEAS-DIC is a new in situ instrument designed to provide calibrated, high-frequency, long-term measurements of DIC in marine and fresh waters. Sample water is first acidified to convert all DIC to carbon dioxide (CO2). The sample and a known reagent solution are then equilibrated across a gas-permeable membrane. Spectrophotometric measurement of reagent pH can thereby determine the sample DIC over a wide dynamic range, with inherent calibration provided by the pH indicator's molecular characteristics. Field trials indicate that SEAS-DIC performs well in biofouling and turbid waters, with a DIC accuracy and precision of ∼2 μmol kg(-1) and a measurement rate of approximately once per minute. The acidic reagent protects the sensor cell from biofouling, and the gas-permeable membrane excludes particulates from the optical path. This instrument, the first spectrophotometric system capable of automated in situ DIC measurements, positions DIC to become a key parameter for in situ CO2-system characterizations.

International Space Station (ISS) Orbital Replaceable Unit (ORU) Wet Storage Risk Assessment

NASA Technical Reports Server (NTRS)

Squire, Michael D.; Rotter, Henry A.; Lee, Jason; Packham, Nigel; Brady, Timothy K.; Kelly, Robert; Ott, C. Mark

2014-01-01

The International Space Station (ISS) Program requested the NASA Engineering and Safety Center (NESC) to evaluate the risks posed by the practice of long-term wet storage of ISS Environmental Control and Life Support (ECLS) regeneration system orbital replacement units (ORUs). The ISS ECLS regeneration system removes water from urine and humidity condensate and converts it into potable water and oxygen. A total of 29 ORUs are in the ECLS system, each designed to be replaced by the ISS crew when necessary. The NESC assembled a team to review the ISS ECLS regeneration system and evaluate the potential for biofouling and corrosion. This document contains the outcome of the evaluation.

Microsphere erosion in outer hydrogel membranes creating macroscopic porosity to counter biofouling-induced sensor degradation.

PubMed

Vaddiraju, S; Wang, Y; Qiang, L; Burgess, D J; Papadimitrakopoulos, F

2012-10-16

Biofouling and tissue inflammation present major challenges toward the realization of long-term implantable glucose sensors. Following sensor implantation, proteins and cells adsorb on sensor surfaces to not only inhibit glucose flux but also signal a cascade of inflammatory events that eventually lead to permeability-reducing fibrotic encapsulation. The use of drug-eluting hydrogels as outer sensor coatings has shown considerable promise to mitigate these problems via the localized delivery of tissue response modifiers to suppress inflammation and fibrosis, along with reducing protein and cell absorption. Biodegradable poly (lactic-co-glycolic) acid (PLGA) microspheres, encapsulated within a poly (vinyl alcohol) (PVA) hydrogel matrix, present a model coating where the localized delivery of the potent anti-inflammatory drug dexamethasone has been shown to suppress inflammation over a period of 1-3 months. Here, it is shown that the degradation of the PLGA microspheres provides an auxiliary venue to offset the negative effects of protein adsorption. This was realized by: (1) the creation of fresh porosity within the PVA hydrogel following microsphere degradation (which is sustained until the complete microsphere degradation) and (2) rigidification of the PVA hydrogel to prevent its complete collapse onto the newly created void space. Incubation of the coated sensors in phosphate buffered saline (PBS) led to a monotonic increase in glucose permeability (50%), with a corresponding enhancement in sensor sensitivity over a 1 month period. Incubation in serum resulted in biofouling and consequent clogging of the hydrogel microporosity. This, however, was partially offset by the generated macroscopic porosity following microsphere degradation. As a result of this, a 2-fold recovery in sensor sensitivity for devices with microsphere/hydrogel composite coatings was observed as opposed to similar devices with blank hydrogel coatings. These findings suggest that the use of macroscopic porosity can reduce sensitivity drifts resulting from biofouling, and this can be achieved synergistically with current efforts to mitigate negative tissue responses through localized and sustained drug delivery.

Period four metal nanoparticles on the inhibition of biofouling.

PubMed

Chapman, James; Weir, Emma; Regan, Fiona

2010-07-01

Biofilms present operational problems to a variety of industrial areas including but not limited to, medicine, water treatment, sensor sensitivity and shipping. Bacterial adhesion resides as a tiny monolayer and builds-up over time with the production of protective slimes known as extracellular polymeric substances (EPS) forming the 'biofilm'. Infection, inefficiency and diminution of quality are caused by biofilms, which have the potential to be prohibitively expensive to repair. The value of an effective coating that prevents the adhesion of bacteria and subsequent fouling is paramount in preserving sensitivity and longevity of a subjected operational substrate. Polymer and sol-gel (SG) based coatings tender a matrix for the introduction of biocides and antimicrobial agents that offer this prevention. They present a relatively cheap and optically clear platform that can then be doped with the antimicrobial agent. This proves useful in transferring across a range of industries that may require a transparent function to the coating. Nanoparticles offer a means of new line research in combating biofouling and biocorrosion with interest stemming from silver metal nanoparticles (MNPs) that already offer antimicrobial property. The aim of this work is to investigate period four metal nanoparticles for any antimicrobial potential they offer, in the prevention of fouling in the early stages. The research presented herein uses a range of period four MNPs synthesised through an adapted polyol reduction, which have then been doped into SG coatings and tested for their efficacy in preventing levels of biofouling. After a 7-day freshwater study results showed that MNPs prevent levels of biofouling upto 125% compared to the SG blank. The work uses bacterial enumeration, minimum inhibitory concentration (MIC), surface characterisation and slime and biomass analysis to complete a range of studies in assessing the level of fouling observed on the test substrates. 2010 Elsevier B.V. All rights reserved.

Control of biofouling by xanthine oxidase on seawater reverse osmosis membranes from a desalination plant: enzyme production and screening of bacterial isolates from the full-scale plant.

PubMed

Nagaraj, V; Skillman, L; Li, D; Xie, Z; Ho, G

2017-07-01

Control of biofouling on seawater reverse osmosis (SWRO) membranes is a major challenge as treatments can be expensive, damage the membrane material and often biocides do not remove the polymers in which bacteria are embedded. Biological control has been largely ignored for biofouling control. The objective of this study was to demonstrate the effectiveness of xanthine oxidase enzyme against complex fouling communities and then identify naturally occurring bacterial strains that produce the free radical generating enzyme. Initially, 64 bacterial strains were isolated from different locations of the Perth Seawater Desalination Plant. In our preceding study, 25/64 isolates were selected from the culture collection as models for biofouling studies, based on their prevalence in comparison to the genomic bacterial community. In this study, screening of these model strains was performed using a nitroblue tetrazolium assay in the presence of hypoxanthine as substrate. Enzyme activity was measured by absorbance. Nine of 25 strains tested positive for xanthine oxidase production, of which Exiguobacterium from sand filters and Microbacterium from RO membranes exhibited significant levels of enzyme production. Other genera that produced xanthine oxidase were Marinomonas, Pseudomonas, Bacillus, Pseudoalteromonas and Staphylococcus. Strain variations were observed between members of the genera Microbacterium and Bacillus. Xanthine oxidase, an oxidoreductase enzyme that generates reactive oxygen species, is endogenously produced by many bacterial species. In this study, production of the enzyme by bacterial isolates from a full-scale desalination plant was investigated for potential use as biological control of membrane fouling in seawater desalination. We have previously demonstrated that free radicals generated by a commercially available xanthine oxidase in the presence of a hypoxanthine substrate, effectively dispersed biofilm polysaccharides on industrially fouled membranes. Bacterial xanthine oxidase production in the presence of hypoxanthine may prove to be a cost effective, in situ method for alleviation of fouling. © 2017 The Society for Applied Microbiology.

QAC modified PVDF membranes: Antibiofouling performance, mechanisms, and effects on microbial communities in an MBR treating municipal wastewater.

PubMed

Chen, Mei; Zhang, Xingran; Wang, Zhiwei; Wang, Liang; Wu, Zhichao

2017-09-01

Biofouling remains as a critical issue limiting the widespread applications of membrane bioreactors (MBRs). The use of antibiofouling membranes is an emerging method to tackle this issue. In this study, a polyvinylidene fluoride (PVDF) membrane was modified using a quaternary ammonium compound (QAC) to create an antibiofouling membrane. The membrane was used in an MBR and the performance, mechanisms, and effects on microbial communities of this membrane were compared to a control operated in parallel. Results showed that the membrane exhibited a significantly reduced transmembrane pressure increase rate of 0.29 kPa/d compared with 0.91 kPa/d of the control. Analysis using a confocal laser scanning microscope (CLSM) revealed almost complete lack of living microbes on the antibiofouling membrane in contrast to the control. However, specific oxygen uptake rate and dehydrogenase activity analyses demonstrated no adverse impacts on microbial viability of the bulk activated sludge. Bacterial population analysis using the Illumina Miseq platform added further evidence that the use of antibiofouling membrane did not exert negative influences on richness, diversity and structure of the bacterial community. Effluent quality of the test MBR also exhibited minimal difference from that of the control reactor. The amount of polysaccharides and proteins in the biofouling layer was also significantly reduced. Quartz crystal microbalance with dissipation monitoring suggested that the antibiofouling membrane only allowed organic matter with strong adhesion properties to attach onto the membrane surfaces. These findings highlight the potential of the antibiofouling membrane to be used in MBRs for wastewater treatment and reclamation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Aluminum phosphate coatings

DOEpatents

Sambasivan, Sankar; Steiner, Kimberly A.; Rangan, Krishnaswamy K.

2007-12-25

Aluminophosphate compounds and compositions as can be used for substrate or composite films and coating to provide or enhance, without limitation, planarization, anti-biofouling and/or anti-microbial properties.

Comparing Biofouling Control Treatments for Use on Aquaculture Nets

PubMed Central

Swain, Geoffrey; Shinjo, Nagahiko

2014-01-01

Test panels comprised of uncoated, copper coated and silicone coated 7/8'' (22 mm) mesh knitted nylon net were evaluated to compare their properties and the effectiveness to prevent biofouling. This paper describes test procedures that were developed to quantify the performance in terms of antifouling, cleanability, drag and cost. The copper treatment was the most effective at controlling fouling, however, the silicone treated nets were the easiest to clean. The drag forces on the net were a function of twine diameter, twine roughness and fouling. After immersion, the uncoated nets had the most drag followed by the silicone and copper treatments. The cost of applying silicone to nets is high; however, improved formulations may provide a non-toxic alternative to control fouling. PMID:25474085

Summary of aluminum nitrate tests at the F/H-ETF

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCabe, D.J.; Wiggins, A.W.

1992-05-01

Biofouling of the Norton ceramic filters in the F/H Effluent Treatment Facility (ETF) has been minimized by bacterial control strategies on the influent streams. However, enough bacteria still exists in the routine influent to impact the filter performance. One method of remediating biofouling in routine influent, initially observed in laboratory tests on simulant solutions, involves addition of aluminum nitrate to the influent wastewater. Tests on actual feed at the ETF using aluminum nitrate showed significantly improved performance, with increases in filter permeability of up to four-fold compared to the baseline case. These improvements were only realized after modifications to themore » pH adjustment system were completed which minimized upsets in the pH of the feed solutions.« less

Field Evaluation of Anti-Biofouling Compounds on Optical Instrumentation

NASA Technical Reports Server (NTRS)

McLean, Scott; Schofield, Bryan; Zibordi, Giuseppe; Lewis, Marlon; Hooker, Stanford; Weidemann, Alan

1997-01-01

Biofouling has been a serious question in the stability of optical measurements in the ocean, particularly in moored and drifting buoy applications. Many investigators coat optical surfaces with various compounds to reduce the amount of fouling; to our knowledge, however, there are no objective, in-situ comparative testing of these compounds to evaluate their effectiveness with respect to optical stability relative to untreated controls. We have tested a wide range of compounds at in-situ locations in Halifax Harbour and in the Adriatic Sea on passive optical sensors. Compounds tested include a variety of TBT formulations, antifungal agents, and low-friction silicone-based compounds; time-scales of up to four months were evaluated. The results of these experiments are discussed.

The study of marine corrosion of copper alloys in chlorinated condenser cooling circuits: the role of microbiological components.

PubMed

Carvalho, Maria L; Doma, Jemimah; Sztyler, Magdalena; Beech, Iwona; Cristiani, Pierangela

2014-06-01

The present paper reports the on-line monitoring of corrosion behavior of the CuNi 70:30 and Al brass alloys exposed to seawater and complementary offline microbiological analyses. An electrochemical equipment with sensors specifically set for industrial application and suitable to estimate the corrosion (by linear polarization resistance technique), the biofilm growth (by the BIOX electrochemical probe), the chlorination treatment and other physical-chemical parameters of the water has been used for the on-line monitoring. In order to identify and better characterize the bacteria community present on copper alloys, tube samples were collected after a long period (1year) and short period (2days) of exposition to treated natural seawater (TNSW) and natural seawater (NSW). From the collected samples, molecular techniques such as DNA extraction, polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE) and identification by sequencing were performed to better characterize and identify the microbial biodiversity present in the samples. The monitoring data confirmed the significant role played by biofouling deposition against the passivity of these Cu alloys in seawater and the positive influence of antifouling treatments based on low level dosages. Molecular analysis indicated biodiversity with the presence of Marinobacter, Alteromonas and Pseudomonas species. Copyright © 2013 Elsevier B.V. All rights reserved.

Development of antifouling surfaces to reduce bacterial attachment

NASA Astrophysics Data System (ADS)

Graham, Mary Viola

Bacteria are exceptionally good at adhering to surfaces and forming complex structures known as biofilms. This process, known as biofouling, can cause problems for infrastructure (eg, clogging and damaging pipes), for the food industry (eg, contamination of processing surfaces and equipment, and for the medical industry (eg, contamination of indwelling medical devices). Accordingly, multiple strategies have been explored to combat biofouling, including chemical modification of surfaces, development of antibiotic coatings, and more recently, the use of engineered surface topography. When designed properly, engineered surface topographies can significantly reduce bacterial surface attachment, ultimately limiting surface colonization. In this work, we hypothesized that the morphology, size, spacing, and surface pre-treatment of topographical features should directly correlate with the size and shape of target organisms, in order to reduce biofouling. Topographical features with size and spacing from 0.25 to 2 mum were fabricated in silicone elastomer and tested against rod shaped bacteria with an average size of 0.5 x 2 mum and spherical bacteria (cocci) ranging from 0.5 - 1 μm in diameter. Antifouling properties of the different topographical features were tested in both static and flow-based assays, and under oxygen plasma-treated (hydrophilic) and untreated (hydrophobic) surface conditions. We found that surface pre-treatment universally affects the ability bacteria to attach to surfaces, while surface topography limits attachment in a manner dependent on the bacterial size/shape and the size/spacing of the topography.

In situ spectrophotometric measurement of dissolved inorganic carbon in seawater

USGS Publications Warehouse

Liua, Xuewu; Byrne, Robert H.; Adornato, Lori; Yates, Kimberly K.; Kaltenbacher, Eric; Ding, Xiaoling; Yang, Bo

2013-01-01

Autonomous in situ sensors are needed to document the effects of today’s rapid ocean uptake of atmospheric carbon dioxide (e.g., ocean acidification). General environmental conditions (e.g., biofouling, turbidity) and carbon-specific conditions (e.g., wide diel variations) present significant challenges to acquiring long-term measurements of dissolved inorganic carbon (DIC) with satisfactory accuracy and resolution. SEAS-DIC is a new in situ instrument designed to provide calibrated, high-frequency, long-term measurements of DIC in marine and fresh waters. Sample water is first acidified to convert all DIC to carbon dioxide (CO2). The sample and a known reagent solution are then equilibrated across a gas-permeable membrane. Spectrophotometric measurement of reagent pH can thereby determine the sample DIC over a wide dynamic range, with inherent calibration provided by the pH indicator’s molecular characteristics. Field trials indicate that SEAS-DIC performs well in biofouling and turbid waters, with a DIC accuracy and precision of ∼2 μmol kg–1 and a measurement rate of approximately once per minute. The acidic reagent protects the sensor cell from biofouling, and the gas-permeable membrane excludes particulates from the optical path. This instrument, the first spectrophotometric system capable of automated in situ DIC measurements, positions DIC to become a key parameter for in situ CO2-system characterizations.

Soft contact lens biomaterials from bioinspired phospholipid polymers.

PubMed

Goda, Tatsuro; Ishihara, Kazuhiko

2006-03-01

Soft contact lens (SCL) biomaterials originated from the discovery of a poly(2-hydroxyethyl methacrylate) (poly[HEMA])-based hydrogel in 1960. Incorporation of hydrophilic polymers into poly(HEMA) hydrogels was performed in the 1970-1980s, which brought an increase in the equilibrium water content, leading to an enhancement of the oxygen permeability. Nowadays, the poly(HEMA)-based hydrogels have been applied in disposable SCL. At the same time, high oxygen-permeable silicone hydrogels were produced, which made it possible to continually wear SCL. Recently, numerous trials for improving the water wettability of silicone hydrogels have been performed. However, little attention has been paid to improving their anti-biofouling properties and biocompatibility. Since biomimetic phospholipid polymers possess excellent anti-biofouling properties and biocompatibility they have the potential to play a valuable role in the surface modification of the silicone hydrogel. The representative phospholipid polymers containing a 2-methacryloyloxyethyl phosphorylcholine (MPC) unit suppressed nonspecific protein adsorption, increased cell compatibility and contributed to blood compatible biomaterials. The MPC polymer coating on the silicone hydrogel improved its water wettability and biocompatibility, while maintaining high oxygen permeability compared with the original silicone hydrogel. Furthermore, the newly prepared phospholipid-type intermolecular crosslinker made it possible to synthesize a 100% phospholipid polymer hydrogel that can enhance the anti-biofouling properties and biocompatibility. In this review, the authors discuss how polymer hydrogels should be designed in order to obtain a biocompatible SCL and future perspectives.

Succession of biofilm communities responsible for biofouling of membrane bio-reactors (MBRs)

PubMed Central

Luo, Jinxue; Lv, Pengyi; Zhang, Jinsong; Fane, Anthony G.; McDougald, Diane

2017-01-01

Biofilm formation is one of the main factors associated with membrane biofouling in membrane bioreactors (MBRs). As such, it is important to identify the responsible organisms to develop targeted strategies to control biofouling. This study investigated the composition and changes in the microbial communities fouling MBR membranes over time and correlated those changes with an increase in transmembrane pressure (TMP). Based on qPCR data, bacteria were the dominant taxa of the biofilm (92.9–98.4%) relative to fungi (1.5–6.9%) and archaea (0.03–0.07%). NMDS analysis indicated that during the initial stages of operation, the biofilm communities were indistinguishable from those found in the sludge. However, the biofilm community significantly diverged from the sludge over time and ultimately showed a unique biofilm profile. This suggested that there was strong selection for a group of organisms that were biofilm specialists. This pattern of succession and selection was correlated with the rapid increase in TMP, where bacteria including Rhodospirillales, Sphingomonadales and Rhizobiales dominated the biofilm at this time. While most of the identified fungal OTUs matched Candida sp., the majority of fungal communities were unclassified by 18S rRNA gene sequencing. Collectively, the data suggests that bacteria, primarily, along with fungi may play an important role in the rapid TMP increase and loss of system performance. PMID:28686622

Mini-review: Inhibition of biofouling by marine microorganisms.

PubMed

Dobretsov, Sergey; Abed, Raeid M M; Teplitski, Max

2013-01-01

Any natural or artificial substratum exposed to seawater is quickly fouled by marine microorganisms and later by macrofouling species. Microfouling organisms on the surface of a substratum form heterogenic biofilms, which are composed of multiple species of heterotrophic bacteria, cyanobacteria, diatoms, protozoa and fungi. Biofilms on artificial structures create serious problems for industries worldwide, with effects including an increase in drag force and metal corrosion as well as a reduction in heat transfer efficiency. Additionally, microorganisms produce chemical compounds that may induce or inhibit settlement and growth of other fouling organisms. Since the last review by the first author on inhibition of biofouling by marine microbes in 2006, significant progress has been made in the field. Several antimicrobial, antialgal and antilarval compounds have been isolated from heterotrophic marine bacteria, cyanobacteria and fungi. Some of these compounds have multiple bioactivities. Microorganisms are able to disrupt biofilms by inhibition of bacterial signalling and production of enzymes that degrade bacterial signals and polymers. Epibiotic microorganisms associated with marine algae and invertebrates have a high antifouling (AF) potential, which can be used to solve biofouling problems in industry. However, more information about the production of AF compounds by marine microorganisms in situ and their mechanisms of action needs to be obtained. This review focuses on the AF activity of marine heterotrophic bacteria, cyanobacteria and fungi and covers publications from 2006 up to the end of 2012.

Analysis of hyper-baric biofilms on engineering surfaces formed in the Deep Sea

NASA Astrophysics Data System (ADS)

Meier, A.; Tsaloglou, N. M.; Connelly, D.; Keevil, B.; Mowlem, M.

2012-04-01

Long-term monitoring of the environment is essential to our understanding of global processes, such as global warming, and their impact. As biofilm formation occurs after only short deployment periods in the marine environment, it is a major problem in long-term operation of environmental sensors. This makes the development of anti-fouling strategies for in situ sensors critical to their function. The effects on sensors can range from measurement drift, which can be compensated, to blockage of channels and material degradation, rendering them inoperative. In general, the longer the deployment period the more severe the effects of the biofouling become. Until now, biofilm research has focused mainly on the eutrophic and euphotic zones of the oceans. Hyper-baric biofilms are poorly understood due to difficulties in experimental setup and the assumption that biofouling in these oligotrophic regions could be regarded as insignificant. Our study shows significant biofilm formation occurs in the deep sea. We deployed a variety of materials, typically used in engineering structures, on a 4500 metre deep mooring during a cruise to the Cayman Trough, for 10 days. The materials were clear plain glass, poly-methyl methacrylate (PMMA), Delrin™, and copper, a known antifouling agent. The biofilms were studied by fluorescence microscopy and molecular analysis. For microscopy the nucleic acid stain, SYTO©9, was used and surface coverage was quantified by using a custom MATLAB™ program. Further molecular analyses, including UV Vis spectrometric quantification of DNA, nucleic acid amplification using Polymerase Chain Reaction (PCR), and Denaturing Gradient Gel Electrophoresis (DGGE), were utilised for the analysis of the microbial community composition of these biofilms. Six 16S/18S universal primer sets representative for the three kingdoms, Archea, Bacteria, and Eukarya were used for the PCR and DGGE. Preliminary results from fluorescence microscopy showed that the biofilm coverage on copper and PMMA was a third of that on Delrin™ and less than half the amount seen on glass surfaces. PCR showed that the microorganisms in these biofilms were predominantly Archea . DGGE conditions were optimised for the separation of PCR products from the three kingdoms. Sequencing data is still being processed. These results show that mitigation strategies are essential for any kind of long-term deployments of remote sensors even in the deep sea. Such strategies could consist for example of chlorine production through the electrolysis of seawater, back-flushing sensor channels with various chemicals, thin films of nickel/copper/zinc alloys in various ratios as surface treatments, quorum-sensing, furanone-treatment and micro-structuring of surfaces.

Cytotoxicity assessment of antibiofouling compounds and by-products in marine bivalve cell cultures.

PubMed

Domart-Coulon, I; Auzoux-Bordenave, S; Doumenc, D; Khalanski, M

2000-06-01

Short-term primary cell cultures were derived from adult marine bivalve tissues: the heart of oyster Crassostrea gigas and the gill of clam Ruditapes decussatus. These cultures were used as experimental in vitro models to assess the acute cytotoxicity of an organic molluscicide, Mexel-432, used in antibiofouling treatments in industrial cooling water systems. A microplate cell viability assay, based on the enzymatic reduction of tetrazolium dye (MTT) in living bivalve cells, was adapted to test the cytotoxicity of this compound: in both in vitro models, toxicity thresholds of Mexel-432 were compared to those determined in vivo with classic acute toxicity tests. The clam gill cell model was also used to assess the cytotoxicity of by-products of chlorination, a major strategy of biofouling control in the marine environment. The applications and limits of these new in vitro models for monitoring aquatic pollutants were discussed, in reference with the standardized Microtox test.

Gasometer: An inexpensive device for continuous monitoring of dissolved gases and supersaturation

USGS Publications Warehouse

Bouck, G.R.

1982-01-01

The “gasometer” is a device that measures differential dissolved-gas pressures (δP) in water relative to barometric pressure (as does the “Weiss saturometer”), but operates continuously without human attention. The gasometer can be plumbed into a water-supply system and requires 8 liters/minute of water or more at 60 kilopascals. The gasometer's surfaces are nontoxic, and flow-through water can be used for fish culture. The gasometer may be connected to a small submersible pump and operated as a portable unit. The gasometer can activate an alarm system and thus protect fish from hyperbaric (supersaturation) or hypobaric gas pressures (usually due to low dissolved oxygen). Instructions are included for calculating and reporting data including the pressure and saturation of individual gases. Construction and performance standards are given for the gasometer. Occasional cleaning is required to remove biofouling from the gas-permeable tubing.PDF

Artificial reefs and reef restoration in the Laurentian Great Lakes

USGS Publications Warehouse

McLean, Matthew W.; Roseman, Edward; Pritt, Jeremy J.; Kennedy, Gregory W.; Manny, Bruce A.

2015-01-01

We reviewed the published literature to provide an inventory of Laurentian Great Lakes artificial reef projects and their purposes. We also sought to characterize physical and biological monitoring for artificial reef projects in the Great Lakes and determine the success of artificial reefs in meeting project objectives. We found records of 6 artificial reefs in Lake Erie, 8 in Lake Michigan, 3 in Lakes Huron and Ontario, and 2 in Lake Superior. We found 9 reefs in Great Lakes connecting channels and 6 reefs in Great Lakes tributaries. Objectives of artificial reef creation have included reducing impacts of currents and waves, providing safe harbors, improving sport-fishing opportunities, and enhancing/restoring fish spawning habitats. Most reefs in the lakes themselves were incidental (not created purposely for fish habitat) or built to improve local sport fishing, whereas reefs in tributaries and connecting channels were more frequently built to benefit fish spawning. Levels of assessment of reef performance varied; but long-term monitoring was uncommon as was assessment of physical attributes. Artificial reefs were often successful at attracting recreational species and spawning fish; however, population-level benefits of artificial reefs are unclear. Stressors such as sedimentation and bio-fouling can limit the effectiveness of artificial reefs as spawning enhancement tools. Our investigation underscores the need to develop standard protocols for monitoring the biological and physical attributes of artificial structures. Further, long-term monitoring is needed to assess the benefits of artificial reefs to fish populations and inform future artificial reef projects.

Electrochemical Quartz Crystal Microbalance with Dissipation Real-Time Hydrodynamic Spectroscopy of Porous Solids in Contact with Liquids.

PubMed

Sigalov, Sergey; Shpigel, Netanel; Levi, Mikhael D; Feldberg, Moshe; Daikhin, Leonid; Aurbach, Doron

2016-10-18

Using multiharmonic electrochemical quartz crystal microbalance with dissipation (EQCM-D) monitoring, a new method of characterization of porous solids in contact with liquids has been developed. The dynamic gravimetric information on the growing, dissolving, or stationary stored solid deposits is supplemented by their precise in-operando porous structure characterization on a mesoscopic scale. We present a very powerful method of quartz-crystal admittance modeling of hydrodynamic solid-liquid interactions in order to extract the porous structure parameters of solids during their formation in real time, using different deposition modes. The unique hydrodynamic spectroscopic characterization of electrolytic and rf-sputtered solid Cu coatings that we use for our "proof of concept" provides a new strategy for probing various electrochemically active thin and thick solid deposits, thereby offering inexpensive, noninvasive, and highly efficient quantitative control over their properties. A broad spectrum of applications of our method is proposed, from various metal electroplating and finishing technologies to deeper insight into dynamic build-up and subsequent development of solid-electrolyte interfaces in the operation of Li-battery electrodes, as well as monitoring hydrodynamic consequences of metal corrosion, and growth of biomass coatings (biofouling) on different solid surfaces in seawater.

75 FR 3272 - Shipping Coordinating Committee; Notice of Committee Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-20

... amendments. --Application of the requirements for the carriage of bio-fuels and bio-fuel blends... through bio-fouling of ships. --Revision of the IGC Code. --Safety requirements for natural gas hydrate...

Chemical Component and Proteomic Study of the Amphibalanus (= Balanus) amphitrite Shell

PubMed Central

Zhang, Gen; He, Li-sheng; Wong, Yue-Him; Xu, Ying; Zhang, Yu; Qian, Pei-yuan

2015-01-01

As typical biofoulers, barnacles possess hard shells and cause serious biofouling problems. In this study, we analyzed the protein component of the barnacle Amphibalanus (= Balanus) amphitrite shell using gel-based proteomics. The results revealed 52 proteins in the A. Amphitrite shell. Among them, 40 proteins were categorized into 11 functional groups based on KOG database, and the remaining 12 proteins were unknown. Besides the known proteins in barnacle shell (SIPC, carbonic anhydrase and acidic acid matrix protein), we also identified chorion peroxidase, C-type lectin-like domains, serine proteases and proteinase inhibitor proteins in the A. Amphitrite shell. The sequences of these proteins were characterized and their potential functions were discussed. Histology and DAPI staining revealed living cells in the shell, which might secrete the shell proteins identified in this study. PMID:26222041

Mini-Review: Antifouling Natural Products from Marine Microorganisms and Their Synthetic Analogs

PubMed Central

Wu, Ze-Hong; Wang, Yu; Wang, Chang-Yun; Xu, Ying

2017-01-01

Biofouling causes huge economic loss and generates serious ecological issues worldwide. Marine coatings incorporated with antifouling (AF) compounds are the most common practices to prevent biofouling. With a ban of organotins and an increase in the restrictions regarding the use of other AF alternatives, exploring effective and environmentally friendly AF compounds has become an urgent demand for marine coating industries. Marine microorganisms, which have the largest biodiversity, represent a rich and important source of bioactive compounds and have many medical and industrial applications. This review summarizes 89 natural products from marine microorganisms and 13 of their synthetic analogs with AF EC50 values ≤ 25 μg/mL from 1995 (the first report about marine microorganism-derived AF compounds) to April 2017. Some compounds with the EC50 values < 5 μg/mL and LC50/EC50 ratios > 50 are highlighted as potential AF compounds, and the preliminary analysis of structure-relationship (SAR) of these compounds is also discussed briefly. In the last part, current challenges and future research perspectives are proposed based on opinions from many previous reviews. To provide clear guidance for the readers, the AF compounds from microorganisms and their synthetic analogs in this review are categorized into ten types, including fatty acids, lactones, terpenes, steroids, benzenoids, phenyl ethers, polyketides, alkaloids, nucleosides and peptides. In addition to the major AF compounds which targets macro-foulers, this review also includes compounds with antibiofilm activity since micro-foulers also contribute significantly to the biofouling communities. PMID:28846626

Nanoporous-Gold-Based Electrode Morphology Libraries for Investigating Structure-Property Relationships in Nucleic Acid Based Electrochemical Biosensors.

PubMed

Matharu, Zimple; Daggumati, Pallavi; Wang, Ling; Dorofeeva, Tatiana S; Li, Zidong; Seker, Erkin

2017-04-19

Nanoporous gold (np-Au) electrode coatings significantly enhance the performance of electrochemical nucleic acid biosensors because of their three-dimensional nanoscale network, high electrical conductivity, facile surface functionalization, and biocompatibility. Contrary to planar electrodes, the np-Au electrodes also exhibit sensitive detection in the presence of common biofouling media due to their porous structure. However, the pore size of the nanomatrix plays a critical role in dictating the extent of biomolecular capture and transport. Small pores perform better in the case of target detection in complex samples by filtering out the large nonspecific proteins. On the other hand, larger pores increase the accessibility of target nucleic acids in the nanoporous structure, enhancing the detection limits of the sensor at the expense of more interference from biofouling molecules. Here, we report a microfabricated np-Au multiple electrode array that displays a range of electrode morphologies on the same chip for identifying feature sizes that reduce the nonspecific adsorption of proteins but facilitate the permeation of target DNA molecules into the pores. We demonstrate the utility of the electrode morphology library in studying DNA functionalization and target detection in complex biological media with a special emphasis on revealing ranges of electrode morphologies that mutually enhance the limit of detection and biofouling resilience. We expect this technique to assist in the development of high-performance biosensors for point-of-care diagnostics and facilitate studies on the electrode structure-property relationships in potential applications ranging from neural electrodes to catalysts.

Preparation, anti-biofouling and drag-reduction properties of a biomimetic shark skin surface

PubMed Central

Pu, Xia; Li, Guangji; Huang, Hanlu

2016-01-01

ABSTRACT Shark skin surfaces show non-smoothness characteristics due to the presence of a riblet structure. In this study, biomimetic shark skin was prepared by using the polydimethylsiloxane (PDMS)-embedded elastomeric stamping (PEES) method. Scanning electron microscopy (SEM) was used to examine the surface microstructure and fine structure of shark skin and biomimetic shark skin. To analyse the hydrophobic mechanism of the shark skin surface microstructure, the effect of biomimetic shark skin surface microstructure on surface wettability was evaluated by recording water contact angle. Additionally, protein adhesion experiments and anti-algae adhesion performance testing experiments were used to investigate and evaluate the anti-biofouling properties of the surface microstructure of biomimetic shark skin. The recorded values of the water contact angle of differently microstructured surfaces revealed that specific microstructures have certain effects on surface wettability. The anti-biofouling properties of the biomimetic shark skin surface with microstructures were superior to a smooth surface using the same polymers as substrates. Moreover, the air layer fixed on the surface of the biomimetic shark skin was found to play a key role in their antibiont adhesion property. An experiment into drag reduction was also conducted. Based on the experimental results, the microstructured surface of the prepared biomimetic shark skin played a significant role in reducing drag. The maximum of drag reduction rate is 12.5%, which is higher than the corresponding maximum drag reduction rate of membrane material with a smooth surface. PMID:26941105

Preparation, anti-biofouling and drag-reduction properties of a biomimetic shark skin surface.

PubMed

Pu, Xia; Li, Guangji; Huang, Hanlu

2016-04-15

Shark skin surfaces show non-smoothness characteristics due to the presence of a riblet structure. In this study, biomimetic shark skin was prepared by using the polydimethylsiloxane (PDMS)-embedded elastomeric stamping (PEES) method. Scanning electron microscopy (SEM) was used to examine the surface microstructure and fine structure of shark skin and biomimetic shark skin. To analyse the hydrophobic mechanism of the shark skin surface microstructure, the effect of biomimetic shark skin surface microstructure on surface wettability was evaluated by recording water contact angle. Additionally, protein adhesion experiments and anti-algae adhesion performance testing experiments were used to investigate and evaluate the anti-biofouling properties of the surface microstructure of biomimetic shark skin. The recorded values of the water contact angle of differently microstructured surfaces revealed that specific microstructures have certain effects on surface wettability. The anti-biofouling properties of the biomimetic shark skin surface with microstructures were superior to a smooth surface using the same polymers as substrates. Moreover, the air layer fixed on the surface of the biomimetic shark skin was found to play a key role in their antibiont adhesion property. An experiment into drag reduction was also conducted. Based on the experimental results, the microstructured surface of the prepared biomimetic shark skin played a significant role in reducing drag. The maximum of drag reduction rate is 12.5%, which is higher than the corresponding maximum drag reduction rate of membrane material with a smooth surface. © 2016. Published by The Company of Biologists Ltd.

Optimisation of biocide dose as a function of residual biocide in a heat exchanger pilot plant effluent.

PubMed

Eguía, Emilio; Trueba, Alfredo; Girón, Alfredo; Río-Calonge, Belén; Otero, Félix; Bielva, Carlos

2007-01-01

Biofouling is one of the most serious problems facing numerous industrial processes. In the case of a heat exchanger unit, biological deposits adhering to the inside surface of its tubes reduce heat transfer and, thus, the thermal performance of the cycle. Control of this phenomenon is proving fundamental for both land and marine equipment to operate in optimum working conditions. Hence, it is necessary to apply antifouling methods capable of keeping surfaces free of any kind of biofouling. This paper reports on the behaviour resulting from use of the flow inversion method vs that obtained by using various chemical treatments. The study compares the effectiveness of certain chemical treatments (Na hypochlorite, peracetic acid and a compound formed by Na bromide + Na hypochlorite) for removing a biofouling film that has already formed on the inside surfaces of tubes in a heat exchanger pilot plant. The paper also addresses the issue of optimising the concentration of biocide dose as a function of the residual biocide in order minimise the environmental impact caused by effluent from industrial plants. The results indicate that it is possible to eliminate a biofilm formed on the inside surfaces of tubes by the use of intermittent doses of chemical treatments at low concentrations and over long application times. Furthermore, once the stabilisation phase is reached 6 d after starting the treatment, it is possible to maintain the conditions achieved using only 20% of the initial dosage.

Three dimensional tracking of exploratory behavior of barnacle cyprids using stereoscopy.

PubMed

Maleschlijski, S; Sendra, G H; Di Fino, A; Leal-Taixé, L; Thome, I; Terfort, A; Aldred, N; Grunze, M; Clare, A S; Rosenhahn, B; Rosenhahn, A

2012-12-01

Surface exploration is a key step in the colonization of surfaces by sessile marine biofoulers. As many biofouling organisms can delay settlement until a suitable surface is encountered, colonization can comprise surface exploration and intermittent swimming. As such, the process is best followed in three dimensions. Here we present a low-cost transportable stereoscopic system consisting of two consumer camcorders. We apply this novel apparatus to behavioral analysis of barnacle larvae (≈800 μm length) during surface exploration and extract and analyze the three-dimensional patterns of movement. The resolution of the system and the accuracy of position determination are characterized. As a first practical result, three-dimensional swimming trajectories of the cypris larva of the barnacle Semibalanus balanoides are recorded in the vicinity of a glass surface and close to PEG2000-OH and C(11)NMe(3)(+)Cl(-) terminated self-assembled monolayers. Although less frequently used in biofouling experiments due to its short reproductive season, the selected model species [Marechal and Hellio (2011), Int Biodeterior Biodegrad, 65(1):92-101] has been used following a number of recent investigations on the settlement behavior on chemically different surfaces [Aldred et al. (2011), ACS Appl Mater Interfaces, 3(6):2085-2091]. Experiments were scheduled to match the availability of cyprids off the north east coast of England so that natural material could be used. In order to demonstrate the biological applicability of the system, analysis of parameters such as swimming direction, swimming velocity and swimming angle are performed.

Treatment with activated water by GlidArc technology of bacteria producing Biofouling

NASA Astrophysics Data System (ADS)

Hnatiuc, B.; Ghita, S.; Sabau, A.; Hnatiuc, M.; Dumitrache, C. L.; Wartel, M.

2015-02-01

Corrosion in marine environment is an actual problem, being a complex dynamic process influenced mainly by physical, chemical, microbiological and mechanical parameters. Around 70% of the maintenance costs of a ship are associated with the corrosion protection. Times for maintenance related to this phenomenon are greater than 80% of the total repair. Reducing this cost would be a significant saving, and an effective treatment can reduce times related to ships repairing. Biofouling is a main cause of corrosion and for its reduction different methods could be applied, especially in the first part of its production. The atmospheric pressure non-thermal plasmas have been gaining an ever increasing interest for different biodecontamination applications and present potential utilisation in the control of biofouling and biodeterioration. They have a high efficiency of the antimicrobial treatment, including capacity to eradicate microbial biofilms. The adhesion microbial biofilm is mainly influenced by presence of bacteria from the liquid environment. That is why this work concerns the study of annihilation of maximum amount of bacteria from sea water, by using GlidArc technology that produces non-thermal plasma. Bacteria suspended in sea water are placed in contact with activated water. This water is activated by using GlidArc working in humid air. Experimental results refer to the number of different activated and inactivated marine organisms and their evolution, present in solution at certain time intervals after mixing different amounts of seawater with plasma activated water.

Mini-Review: Antifouling Natural Products from Marine Microorganisms and Their Synthetic Analogs.

PubMed

Wang, Kai-Ling; Wu, Ze-Hong; Wang, Yu; Wang, Chang-Yun; Xu, Ying

2017-08-28

Biofouling causes huge economic loss and generates serious ecological issues worldwide. Marine coatings incorporated with antifouling (AF) compounds are the most common practices to prevent biofouling. With a ban of organotins and an increase in the restrictions regarding the use of other AF alternatives, exploring effective and environmentally friendly AF compounds has become an urgent demand for marine coating industries. Marine microorganisms, which have the largest biodiversity, represent a rich and important source of bioactive compounds and have many medical and industrial applications. This review summarizes 89 natural products from marine microorganisms and 13 of their synthetic analogs with AF EC 50 values ≤ 25 μg/mL from 1995 (the first report about marine microorganism-derived AF compounds) to April 2017. Some compounds with the EC 50 values < 5 μg/mL and LC 50 /EC 50 ratios > 50 are highlighted as potential AF compounds, and the preliminary analysis of structure-relationship (SAR) of these compounds is also discussed briefly. In the last part, current challenges and future research perspectives are proposed based on opinions from many previous reviews. To provide clear guidance for the readers, the AF compounds from microorganisms and their synthetic analogs in this review are categorized into ten types, including fatty acids, lactones, terpenes, steroids, benzenoids, phenyl ethers, polyketides, alkaloids, nucleosides and peptides. In addition to the major AF compounds which targets macro-foulers, this review also includes compounds with antibiofilm activity since micro-foulers also contribute significantly to the biofouling communities.

Evidence of compositional and ultrastructural shifts during the development of calcareous tubes in the biofouling tubeworm, Hydroides elegans.

PubMed

Chan, Vera Bin San; Vinn, Olev; Li, Chaoyi; Lu, Xingwen; Kudryavtsev, Anatoliy B; Schopf, J William; Shih, Kaimin; Zhang, Tong; Thiyagarajan, Vengatesen

2015-03-01

The serpulid tubeworm, Hydroides elegans, is an ecologically and economically important species whose biology has been fairly well studied, especially in the context of larval development and settlement on man-made objects (biofouling). Nevertheless, ontogenetic changes associated with calcareous tube composition and structures have not yet been studied. Here, the ultrastructure and composition of the calcareous tubes built by H. elegans was examined in the three early calcifying juvenile stages and in the adult using XRD, FTIR, ICP-OES, SEM and Raman spectroscopy. Ontogenetic shifts in carbonate mineralogy were observed, for example, juvenile tubes contained more amorphous calcium carbonate and were predominantly aragonitic whereas adult tubes were bimineralic with considerably more calcite. The mineral composition gradually shifted during the tube development as shown by a decrease in Sr/Ca and an increase of Mg/Ca ratios with the tubeworm's age. The inner tube layer contained calcite, whereas the outer layer contained aragonite. Similarly, the tube complexity in terms of ultrastructure was associated with development. The sequential appearance of unoriented ultrastructures followed by oriented ultrastructures may reflect the evolutionary history of serpulid tube biominerals. As aragonitic structures are more susceptible to dissolution under ocean acidification (OA) conditions but are more difficult to be removed by anti-fouling treatments, the early developmental stages of the tubeworms may be vulnerable to OA but act as the important target for biofouling control. Copyright © 2015 Elsevier Inc. All rights reserved.

The application of nitric oxide to control biofouling of membrane bioreactors

PubMed Central

Luo, Jinxue; Zhang, Jinsong; Barnes, Robert J; Tan, Xiaohui; McDougald, Diane; Fane, Anthony G; Zhuang, Guoqiang; Kjelleberg, Staffan; Cohen, Yehuda; Rice, Scott A

2015-01-01

A novel strategy to control membrane bioreactor (MBR) biofouling using the nitric oxide (NO) donor compound PROLI NONOate was examined. When the biofilm was pre-established on membranes at transmembrane pressure (TMP) of 88–90 kPa, backwashing of the membrane module with 80 μM PROLI NONOate for 45 min once daily for 37 days reduced the fouling resistance (Rf) by 56%. Similarly, a daily, 1 h exposure of the membrane to 80 μM PROLI NONOate from the commencement of MBR operation for 85 days resulted in reduction of the TMP and Rf by 32.3% and 28.2%. The microbial community in the control MBR was observed to change from days 71 to 85, which correlates with the rapid TMP increase. Interestingly, NO-treated biofilms at 85 days had a higher similarity with the control biofilms at 71 days relative to the control biofilms at 85 days, indicating that the NO treatment delayed the development of biofilm bacterial community. Despite this difference, sequence analysis indicated that NO treatment did not result in a significant shift in the dominant fouling species. Confocal microscopy revealed that the biomass of biopolymers and microorganisms in biofilms were all reduced on the PROLI NONOate-treated membranes, where there were reductions of 37.7% for proteins and 66.7% for microbial cells, which correlates with the reduction in TMP. These results suggest that NO treatment could be a promising strategy to control biofouling in MBRs. PMID:25752591

In vivo continuous and simultaneous monitoring of brain energy substrates with a multiplex amperometric enzyme-based biosensor device.

PubMed

Cordeiro, C A; de Vries, M G; Ngabi, W; Oomen, P E; Cremers, T I F H; Westerink, B H C

2015-05-15

Enzyme-based amperometric biosensors are widely used for monitoring key biomarkers. In experimental neuroscience there is a growing interest in in vivo continuous and simultaneous monitoring of metabolism-related biomarkers, like glucose, lactate and pyruvate. The use of multiplex biosensors will provide better understanding of brain energy metabolism and its role in neuropathologies such as diabetes, ischemia, and epilepsy. We have developed and characterized an implantable multiplex microbiosensor device (MBD) for simultaneous and continuous in vivo monitoring of glucose, lactate, and pyruvate. First, we developed and characterized amperometric microbiosensors for monitoring lactate and pyruvate. In vitro evaluation allowed us to choose the most suitable biosensors for incorporation into the MBD, along with glucose and background biosensors. Fully assembled MBDs were characterized in vitro. The calculated performance parameters (LOD, LR, LRS, IMAX and appKM) showed that the multiplex MBD was highly selective and sensitive (LRS≥100 nA/mM) for each analyte and within an adequate range for in vivo application. Finally, MBDs were implanted in the mPFC of anesthetized adult male Wistar rats for in vivo evaluation. Following an equilibration period, baseline brain levels of glucose (1.3±0.2 mM), lactate (1.5±0.4 mM) and pyruvate (0.3±0.1 mM) were established. Subsequently, the MBDs recorded the responses of the animals when submitted to hyperglycemic (40% glucose i.v.) and hypoglycemic (5 U/kg insulin i.v.) challenges. Afterwards, MBDs were recalibrated to convert electrochemical readings into accurate substrate concentrations and to assess biofouling. The presented MBD can monitor simultaneously multiple biomarkers in vivo. Copyright © 2014 Elsevier B.V. All rights reserved.

75 FR 82129 - Shipping Coordinating Committee; Notice of Committee Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-29

... consequential amendments; -- Application of the requirements for the carriage of bio-fuels and bio-fuel blends... through bio-fouling of ships; -- Revision of the IGC Code; -- Review of relevant non-mandatory instruments...

Geochemistry and microbiology of iron-related well-screen encrustation and aquifer biofouling in Suffolk County, Long Island, New York

USGS Publications Warehouse

Walter, D.A.

1997-01-01

Iron-related well-screen encrustation and aquifer biofouling has decreased the specific capacity of several production wells in Suffolk County, N.Y., and has forced the Suffolk County Water Authority to adopt a costly well-reconditioning and replacement program. The specific-capacity declines are the result of the precipitation of iron oxyhydroxides and the growth of iron bacteria on the well screens and in the pore spaces of the surrounding formation. Mineralogic and chemical analyses indicate that the inorganic part of the encrusting material consists primarily of amorphous ferric hydroxide (Fe(OH)3 ); minor components of the material include goethite (FeOOH), hematite (Fe2 O 3 ), and quartz (SiO 2 ). The weight percent of ferric hydroxide in the material ranged from 32.3 to 98.6 percent and averaged 64.3 percent. Equilibrium modeling indicated that during pumping the well waters were supersaturated with respect to goethite, hematite, magnetite, and quartz and were under-saturated with respect to ferric hydroxide. Theoretical Eh values computed for the ferrous/ferric-iron redox couple and the oxygen/water redox couple averaged 390 millivolts and 810 millivolts, respectively, indicating that the waters were in a state of redox disequilibrium. The disequilibrium condition arises from the mixing of ground water with a low dissolved-oxygen concentration with oxygenated ground water during operation of the well. The low pH of the ground water contributes to the disequilibrium condition by slowing the rate of iron oxidation after the introduction of oxygen. Chemical and mineralogical data indicate that most of the encrusting material in the wells was deposited while the wells were shut down, probably in response to the use of treated water of higher pH to keep pump turbines wet while the wells were not in operation; the increased pH of water in the static water column increases the rate of ferrous-iron oxidation and causes the well water to become increasingly saturated with respect to ferric hydroxide. The median half-time of oxidation in samples of untreated ground water (pH 4-5) was 4.19 days, whereas the average half-time of oxidation in treated water (pH 7-8) was 11.9 minutes Equilibrium modeling indicated that treated waters generally were supersaturated with respect to ferric hydroxide, whereas untreated well waters were not. Field and laboratory data indicate that iron bacteria play an important role in the encrustation and biofouling process in Suffolk County. Filamentous iron bacteria were common in the affected wells. The most common species was Gallionella ferruginea, an effective biofouling agent that prefers water with low, but detectable, dissolved-oxygen concentrations and high dissolved-iron concentrations; this species was more common in biofilm samples from the Magothy aquifer than in those from the upper glacial aquifer. Iron bacteria also were found in sediment cores from several locations in the aquifer and in drilling water. Lignite could act as a carbon source for heterotrophic iron bacteria, which could accelerate the formation of iron-bacteria biofilms in wells screened in some parts of the Magothy aquifer. Iron-bacteria biofilms alter the chemistry of well water by removing iron, manganese, and sulfate from solution and by increasing the pH. Sulfur-reducing bacteria and iron-sulfide mineral phases were observed in some samples of encrusting material, indicating that these bacteria could contribute to well-screen encrustation in some geochemical environments.

Mitigation of biofouling using electromagnetic fields in tubular heat exchangers-condensers cooled by seawater.

PubMed

Trueba, Alfredo; García, Sergio; Otero, Félix M

2014-01-01

Electromagnetic field (EMF) treatment is presented as an alternative physical treatment for the mitigation of biofouling adhered to the tubes of a heat exchanger-condenser cooled by seawater. During an experimental phase, a fouling biofilm was allowed to grow until experimental variables indicated that its growth had stabilised. Subsequently, EMF treatment was applied to seawater to eliminate the biofilm and to maintain the achieved cleanliness. The results showed that EMFs precipitated ions dissolved in the seawater. As a consequence of the application of EMFs, erosion altered the intermolecular bonding of extracellular polymers, causing the destruction of the biofilm matrix and its detachment from the inner surface of the heat exchanger-condenser tubes. This detachment led to the partial removal of a mature biofilm and a partial recovery of the efficiency lost in the heat transfer process by using a physical treatment that is harmless to the marine environment.

Biofouling on polymeric heat exchanger surfaces with E. coli and native biofilms.

PubMed

Pohl, S; Madzgalla, M; Manz, W; Bart, H J

2015-01-01

The biofouling affinity of different polymeric surfaces (polypropylene, polysulfone, polyethylene terephthalate, and polyether ether ketone) in comparison to stainless steel (SS) was studied for the model bacterium Escherichia coli K12 DSM 498 and native biofilms originating from Rhine water. The biofilm mass deposited on the polymer surfaces was minimized by several magnitudes compared to SS. The cell count and the accumulated biomass of E. coli on the polymer surfaces showed an opposing linear trend. The promising low biofilm formation on the polymers is attributed to the combination of inherent surface properties (roughness, surface energy and hydrophobicity) when compared to SS. The fouling characteristics of E. coli biofilms show good conformity with the more complex native biofilms investigated. The results can be utilized for the development of new polymer heat exchangers when using untreated river water as coolant or for other processes needing antifouling materials.

Cleaning efficacy of hydroxypropyl-beta-cyclodextrin for biofouling reduction on reverse osmosis membranes.

PubMed

Alayande, Abayomi Babatunde; Kim, Lan Hee; Kim, In S

2016-01-01

In this study, an environmentally friendly compound, hydroxypropyl-beta-cyclodextrin (HP-β-CD) was applied to clean reverse osmosis (RO) membranes fouled by microorganisms. The cleaning with HP-β-CD removed the biofilm and resulted in a flux recovery ratio (FRR) of 102%. As cleaning efficiency is sometimes difficult to determine using flux recovery data alone, attached bacterial cells and extracellular polymeric substances (EPS) were quantified after cleaning the biofouled membrane with HP-β-CD. Membrane surface characterization using scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared (ATR-FTIR) and atomic force microscopy (AFM) confirmed the effectiveness of HP-β-CD in removal of biofilm from the RO membrane surface. Finally, a comparative study was performed to investigate the competitiveness of HP-β-CD with other known cleaning agents such as sodium dodecyl sulfate (SDS), ethylenediaminetetraacetic acid (EDTA), Tween 20, rhamnolipid, nisin, and surfactin. In all cases, HP-β-CD was superior.

Environmental assessment of Buccaneer gas and oil field in the northwestern Gulf of Mexico, 1975-1980. Volume II. Fishes and macro-crustaceans/biofouling communities. Technical memo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gallaway, B.J.

1980-11-01

Environmental and ecosystem alterations associated with the development and release of contaminants from an active gas and oil field were found to have been primarily related to the presence of the structures and the discharge of produced water. The presence of the structures contributed to turbulent mixing, and allowed for the development of a rich and diverse biofouling community. The resulting artificial reefs were found to serve as points of aggregation for reef fishes as well as species which prey upon them. The produced waters contained low levels of contaminants and were toxic at varying degrees to all organisms tested.more » The effects of the recreational fisheries associated with petroleum platforms in the Gulf on the stocks of red snapper appear to represent a major area of concern.« less

Antifouling enhancement of polyimide membrane by grafting DEDA-PS zwitterions.

PubMed

Zhang, Dong Yan; Xiong, Shu; Shi, Yu Sheng; Zhu, Jun; Hu, Qiao Li; Liu, Jie; Wang, Yan

2018-05-01

In order to improve the water flux and antifouling property of polyimide (PI) membrane, zwitterions are grafted on PI membrane surface via a two-step modification route by reactions with N,N-diethylethylenediamine (DEDA) and 1,3-propane sultone (PS) sequentially. The reaction mechanism and physicochemical properties of membranes are confirmed via various characterization techniques. The anti-biofouling performance of the zwitterion-grafted PI membranes is evaluated by bacterial suspension immersion tests in Escherichia coli (E. coli) and staphylococcus aureus (S. aureus) solutions. The antifouling property is assessed via the filtration test using the bovine serum albumin (BSA) and dodecyl trimethyl ammonium bromide (DTAB) aqueous feed solutions. The effect of the reaction time with DEDA in the zwitterion-grafted process on the antifouling property is further investigated systematically. The results show that both the anti-biofouling and antifouling performances of zwitterion-grafted PI membranes are significantly improved. Copyright © 2018 Elsevier Ltd. All rights reserved.

Membrane biofouling process correlated to the microbial community succession in an A/O MBR.

PubMed

Chen, Chun-Hong; Fu, Yuan; Gao, Da-Wen

2015-12-01

The microbial community succession of the biofouling layer in a submerged anoxic/oxic membrane biological reactor (A/O MBR) that fed with synthesized domestic wastewater was investigated under three different flux conditions without the changing of the nutrient load. The noticeable microbial community succession and its significant correlation with the metabolic products were observed under the subcritical flux condition. Under the supercritical flux condition, the microbial community shift was in a different pattern compared with that under the subcritical flux condition and it was affected by the increased permeable suction more than the metabolic products. The most abundant microorganisms in the foulants were β-proteobacteria and γ-proteobacteria which can reach more than 20% of the microbial community. However the microorganisms which had significant correlation with the metabolic products were in lower abundance. Copyright © 2015 Elsevier Ltd. All rights reserved.

Application of ozone to eliminate tertiary treatment of wastewater used for industrial cooling

NASA Astrophysics Data System (ADS)

Merrill, D. T.; Parker, D. S.

1982-02-01

The beneficial performance of ozone (biofouling, corrosion, and chemical scaling control), when used as the sole source of cooling water treatment for air conditioning systems, could be obtained at higher cooling water temperatures typical of industrial cooling with secondary municipal effluent (SME) used as the cooling medium was investigated. A pilot cooling system was constructed and a 6 month experimental study initiated to determine process limits, mechanisms of scaling inhibition by ozone, and to evaluate factors influencing technical/economic feasibility. It was found that, while ozone use adequately controlled corrosion and biofouling, chemical scaling could not be prevented at conditions necessary for significant economic justification. Calculations indicate that the makeup waters (SME) used will become saturated with respect to calcium phosphate at less than 2 cycles of concentration, hence, a scaling potential exists at conditions less stringent than those used in the present study.

Spray- and spin-assisted layer-by-layer assembly of copper nanoparticles on thin-film composite reverse osmosis membrane for biofouling mitigation.

PubMed

Ma, Wen; Soroush, Adel; Van Anh Luong, Tran; Brennan, Gregory; Rahaman, Md Saifur; Asadishad, Bahareh; Tufenkji, Nathalie

2016-08-01

Copper nanoparticles (CuNPs) have long been considered as highly effective biocides; however, the lack of suitable methods for loading CuNPs onto polymeric membranes is recognized as being one of the primary reasons for the limited research concerning their application in membrane industries. A highly efficient spray- and spin-assisted layer-by-layer (SSLbL) method was developed to functionalize the TFC polyamide RO membranes with controllable loading of CuNPs for biofouling control. The SSLbL method was able to produce a uniform bilayer of polyethyleneimine-coated CuNPs and poly(acrylic) acid in less than 1 min, which is far more efficient than the traditional dipping approach (25-60 min). The successful loading of CuNPs onto the membrane surface was confirmed by XPS analysis. Increasing the number of bilayers from 2 to 10 led to an increased quantity of CuNPs on the membrane surface, from 1.75 to 23.7 μg cm(-2). Multi-layer coating exhibited minor impact on the membrane water permeation flux (13.3% reduction) while retaining the original salt rejection ability. Both static bacterial inactivation and cross-flow filtration tests demonstrated that CuNPs could significantly improve anti-biofouling property of a polyamide membrane and effectively inhibit the permeate flux reduction caused by bacterial deposition on the membrane surface. Once depleted, CuNPs can also be potentially regenerated on the membrane surface via the same SSLbL method. Copyright © 2016 Elsevier Ltd. All rights reserved.

Heritage materials and biofouling mitigation through UV-C irradiation in show caves: state-of-the-art practices and future challenges.

PubMed

Borderie, Fabien; Alaoui-Sossé, Badr; Aleya, Lotfi

2015-03-01

Biofouling, i.e., colonization of a given substrate by living organisms, has frequently been reported for heritage materials and particularly on stone surfaces such as building facades, historical monuments, and artworks. This also concerns subterranean environments such as show caves, in which the installation of artificial light for tourism has led to the proliferation of phototrophic microorganisms. In Europe nowadays, the use of chemicals in these very sensitive environments is scrutinized and regulated by the European Union. New and environmentally friendly processes must be developed as alternative methods for cave conservation. For several years, the UV irradiation currently used in medical facilities and for the treatment of drinking water has been studied as a new innovative method for the conservation of heritage materials. This paper first presents a review of the biofouling phenomena on stone materials such as building facades and historical monuments. The biological disturbances induced by tourist activity in show caves are then examined, with special attention given to the methods and means to combat them. Thirdly, a general overview is given of the effects of UV-C on living organisms, and especially on photosynthetic microorganisms, through different contexts and studies. Finally, the authors' own experiments and findings are presented concerning the study and use of UV-C irradiation to combat algal proliferation in show caves. Both laboratory and in situ results are summarized and synthesized from their previously published works. The application of UV in caves is discussed and further experiments are proposed to enhance research in this domain.

Determination of uptake kinetics (sampling rates) by lipid-containing semipermeable membrane devices (SPMDs) for polycyclic aromatic hydrocarbons (PAHs) in water

USGS Publications Warehouse

Huckins, J.N.; Petty, J.D.; Orazio, C.E.; Lebo, J.A.; Clark, R.C.; Gibson, V.L.; Gala, W.R.; Echols, K.R.

1999-01-01

The use of lipid-containing semipermeable membrane devices (SPMDs) is becoming commonplace, but very little sampling rate data are available for the estimation of ambient contaminant concentrations from analyte levels in exposed SPMDs. We determined the aqueous sampling rates (R(s)s; expressed as effective volumes of water extracted daily) of the standard (commercially available design) 1-g triolein SPMD for 15 of the priority pollutant (PP) polycyclic aromatic hydrocarbons (PAHs) at multiple temperatures and concentrations. Under the experimental conditions of this study, recovery- corrected R(s) values for PP PAHs ranged from ???1.0 to 8.0 L/d. These values would be expected to be influenced by significant changes (relative to this study) in water temperature, degree of biofouling, and current velocity- turbulence. Included in this paper is a discussion of the effects of temperature and octanol-water partition coefficient (K(ow)); the impacts of biofouling and hydrodynamics are reported separately. Overall, SPMDs responded proportionally to aqueous PAH concentrations; i.e., SPMD R(s) values and SPMD-water concentration factors were independent of aqueous concentrations. Temperature effects (10, 18, and 26 ??C) on Rs values appeared to be complex but were relatively small.The use of lipid-containing semipermeable membrane devices (SPMDs) is becoming commonplace, but very little sampling rate data are available for the estimation of ambient contaminant concentrations from analyte levels in exposed SPMDs. We determined the aqueous sampling rates (Rss; expressed as effective volumes of water extracted daily) of the standard (commercially available design) 1-g triolein SPMD for 15 of the priority pollutant (PP) polycyclic aromatic hydrocarbons (PAHs) at multiple temperatures and concentrations. Under the experimental conditions of this study, recovery-corrected Rs values for PP PAHs ranged from ???1.0 to 8.0 L/d. These values would be expected to be influenced by significant changes (relative to this study) in water temperature, degree of biofouling, and current velocity-turbulence. Included in this paper is a discussion of the effects of temperature and octanol-water partition coefficient (KOW); the impacts of biofouling and hydrodynamics are reported separately. Overall, SPMDs responded proportionally to aqueous PAH concentrations; i.e., SPMD RS values and SPMD-water concentration factors were independent of aqueous concentrations. Temperature effects (10, 18, and 26??C) on RS values appeared to be complex but were relatively small.

Development of a functionalized coating for inhibition of marine corrosion and biofouling

NASA Astrophysics Data System (ADS)

Gittens, Jeanette Elizabeth

The financial loss incurred by corrosion of metals in the marine environment has led to a need to develop effective, economic and environmentally friendly methods of protection. Traditional methods of counteracting the development of surface biofilms and biofouling within aqueous environments have involved implementing chemical biocides, often with a deleterious effect on non-target organisms. Sol gel coating technology offers a convenient route for immobilizing functional additives, such as inhibitors or, in the case of this study, biologically active microorganisms. Paenibacillus polymyxa biofilms inhibit the corrosion of metal substrates and this strain has the advantage of forming endospores can withstand the solvent and acid concentrations required in sol-gel formulation. Encapsulation of viable P. polymyxa endospores within the sol-gel matrix allowed germination on exposure to nutrients, when germinating endospores and vegetative cells were seen after fluorescence microscopy to be distributed throughout the coating. Laboratory electrochemical impedance tests were used to characterize the corrosion behaviour of the endospore-containing (biotic) sol-gel coating in comparison to an abiotic (no endospores) sol-gel only coating and one containing non-viable (killed) endospores. The technology enabled manipulation of the sol-gel formulation and the method of application to produce biotic sol-gel with enhanced corrosion inhibition properties on aluminium alloy. Field trials in a marine environment confirmed the corrosion protecting properties of the biotic coating and that the biotic coatings inhibited macroscopic biofouling for at least 29 weeks relative to the controls without encapsulated live endospores. Production of polymyxin by the encapsulated bacteria, which was proposed as a mechanism by which they inhibit MIC, was less than 1 mug per ml and below the threshold of detection by liquid chromatography mass spectrometry and antimicrobial bioassay. Microcosm experiments were used to study differences in the corrosion of abiotic and biotic coatings in the presence of a corrosion-causing sulphate-reducing bacterium. Scanning electrochemical microscopy was developed as a technique to study electrochemical processes on the coating surface and showed differences in the distribution of copper ions on the surface of abiotic and biotic coatings.The results of the experimental work in this thesis show the potential of encapsulating metabolically active bacterial cells within a sol-gel coating on metals for the control of marine corrosion and biofouling.

Novel microfluidic system for online monitoring of biofilm dynamics by electrical impedance spectroscopy and amperometry

NASA Astrophysics Data System (ADS)

Bruchmann, Julia; Sachsenheimer, Kai; Schwartz, Thomas; Rapp, Bastian E.

2016-03-01

Biofilm formation is ubiquitous in nature where microorganisms attach to surfaces and form highly adapted and protected communities. In technical and industrial systems like drinking water supply, food production or shipping industry biofilms are a major cause of product contamination, biofouling, and biocorrosion. Therefore, understanding of biofilm formation and means of preventing biofilm formation is important to develop novel biofilm treatment strategies. A system allowing directly online detection and monitoring biofilm formation is necessary. However, until today, there are little to none technical systems featuring a non-destructive real-time characterization of biofilm formation in a highthroughput manner. This paper presents such a microfluidic system based on electrical impedance spectroscopy (EIS) and amperomertic current measurement. The sensor consists of four modules, each housing 24 independent electrodes within 12 microfluidic channels. Attached biomass on the electrodes is monitored as increased inhibition in charge transfer by EIS and a change in metabolic activity is measured as change in produced electric current by amperometry. This modular sensor system is highly adaptable and suitable for a broad range of microbiological applications. Among others, biofilm formation processes can be characterized online, biofilm manipulation like inactivation or destabilization can be monitored in real-time and gene expression can be analyzed in parallel. The use of different electrode designs allows effective biofilm studies during all biofilm phases. The whole system was recently extended by an integrated pneumatic microfluidic pump which enables easy handling procedures. Further developments of this pumping module will allow a fully- automated computer-controlled valving and pumping.

Cell Based Metabolic Barriers to Glucose Diffusion: Macrophages and Continuous Glucose Monitoring

PubMed Central

Klueh, Ulrike; Frailey, Jackman; Qiao, Yi; Antar, Omar; Kreutzer, Donald L.

2014-01-01

It is assumed that MQ are central to glucose sensor bio-fouling and therefore have a major negative impact on continuous glucose monitoring (CGM) performance in vivo. However to our knowledge there is no data in the literature to directly support or refute this assumption. Since glucose and oxygen (O2) are key to glucose sensor function in vivo, understanding and controlling glucose and O2 metabolic activity of MQ is likely key to successful glucose sensor performance. We hypothesized that the accumulation of MQ at the glucose sensor-tissue interface will act as “Cell Based Metabolic Barriers” (CBMB) to glucose diffusing from the interstitial tissue compartment to the implanted glucose sensor and as such creating an artificially low sensor output, thereby compromising sensor function and CGM. Our studies demonstrated that 1) direct injections of MQ at in vivo sensor implantation sites dramatically decreased sensor output (measured in nA), 2) addition of MQ to glucose sensors in vitro resulted in a rapid and dramatic fall in sensor output and 3) lymphocytes did not affect sensor function in vitro or in vivo. These data support our hypothesis that MQ can act as metabolic barriers to glucose and O2 diffusion in vivo and in vitro. PMID:24461328

Impact of macrophage deficiency and depletion on continuous glucose monitoring in vivo

PubMed Central

Klueh, Ulrike; Qiao, Yi; Frailey, Jackman T.; Kreutzer, Donald L.

2014-01-01

Although it is assumed that macrophages (MQ) have a major negative impact on continuous glucose monitoring (CGM), surprisingly there is no data in the literature to directly support or refute the role of MQ or related foreign body giant cells in the bio-fouling of glucose sensors in vivo. As such, we developed the hypothesis that MQ are key in controlling glucose sensor performance and CGM in vivo and MQ deficiencies or depletion would enhance CGM. To test this hypothesis we determined the presence/distribution of MQ at the sensor tissue interface over a 28-day time period using F4/80 antibody and immunohistochemical analysis. We also evaluated the impact of spontaneous MQ deficiency (op/op mice) and induced-transgenic MQ depletions (Diphtheria Toxin Receptor (DTR) mice) on sensor function and CGM utilizing our murine CGM system. The results of these studies demonstrated: 1) a time dependent increase in MQ accumulation (F4/80 positive cells) at the sensor tissue interface; and 2) MQ deficient mice and MQ depleted C57BL/6 mice demonstrated improved sensor performance (MARD) when compared to normal mice (C57BL/6). These studies directly demonstrate the importance of MQ in sensor function and CGM in vivo. PMID:24331705

Cell based metabolic barriers to glucose diffusion: macrophages and continuous glucose monitoring.

PubMed

Klueh, Ulrike; Frailey, Jackman T; Qiao, Yi; Antar, Omar; Kreutzer, Donald L

2014-03-01

It is assumed that MQ are central to glucose sensor bio-fouling and therefore have a major negative impact on continuous glucose monitoring (CGM) performance in vivo. However to our knowledge there is no data in the literature to directly support or refute this assumption. Since glucose and oxygen (O2) are key to glucose sensor function in vivo, understanding and controlling glucose and O2 metabolic activity of MQ is likely key to successful glucose sensor performance. We hypothesized that the accumulation of MQ at the glucose sensor-tissue interface will act as "Cell Based Metabolic Barriers" (CBMB) to glucose diffusing from the interstitial tissue compartment to the implanted glucose sensor and as such creating an artificially low sensor output, thereby compromising sensor function and CGM. Our studies demonstrated that 1) direct injections of MQ at in vivo sensor implantation sites dramatically decreased sensor output (measured in nA), 2) addition of MQ to glucose sensors in vitro resulted in a rapid and dramatic fall in sensor output and 3) lymphocytes did not affect sensor function in vitro or in vivo. These data support our hypothesis that MQ can act as metabolic barriers to glucose and O2 diffusion in vivo and in vitro. Copyright © 2014 Elsevier Ltd. All rights reserved.

Environmentally benign sol-gel antifouling and foul-releasing coatings.

PubMed

Detty, Michael R; Ciriminna, Rosaria; Bright, Frank V; Pagliaro, Mario

2014-02-18

Biofouling on ships and boats, characterized by aquatic bacteria and small organisms attaching to the hull, is an important global issue, since over 80000 tons of antifouling paint is used annually. This biofilm, which can form in as little as 48 hours depending on water temperature, increases drag on watercraft, which greatly reduces their fuel efficiency. In addition, biofouling can lead to microbially induced corrosion (MIC) due to H2S formed by the bacteria, especially sulfate-reducing bacteria. When the International Maritime Organization (IMO) international convention banned the use of effective but environmentally damaging coatings containing tributyl tin in 2008, the development of clean and effective antifouling systems became more important than ever. New nonbiocidal coatings are now in high demand. Scientists have developed new polymers, materials, and biocides, including new elastomeric coatings that they have obtained by improving the original silicone (polydimethylsiloxane) formulation patented in 1975. However, the high cost of silicones, especially of fluoropolymer-modified silicones, has generally prevented their large-scale diffusion. In 2009, traditional antifouling coatings using cuprous oxide formulated in copolymer paints still represented 95% of the global market volume of anti-fouling paints. The sol-gel nanochemistry approach to functional materials has emerged as an attractive candidate for creating low fouling surfaces due to the unique structure and properties of silica-based coatings and of hybrid inorganic-organic silicas in particular. Sol-gel formulations easily bind to all types of surfaces, such as steel, fiberglass, aluminum, and wood. In addition, they can cure at room temperature and form thin glassy coatings that are markedly different from thick silicone elastomeric foul-releasing coatings. Good to excellent performance against biofouling, low cure temperatures, enhanced and prolonged chemical and physical stability, ease of application, and the waterborne nature of sol-gel coatings all support the diffusion of these paints to efficiently reduce the accumulation of fouling layers on valued surfaces immersed in marine or fluvial waters. Furthermore, sol-gel glassy coatings are transparent and can be effectively applied to optical devices, windows, and solar panels used in lake, fluvial, or marine environments. Sol-gel technology is eminently versatile, and the first generation sol-gel paints have already shown good performance. Even so, vast opportunities still exist for chemists to develop novel sol-gel derived coatings to both prevent biofouling and enhance the hydrodynamic properties of boat and ship hulls. Moreover, researchers have prepared and applied multifunctional sol-gel coatings providing protection against both biofouling and corrosion. They have tested these in the marine environment with good preliminary results. In this Account, we discuss some of our new strategies for the controlled functionalization of surfaces for the development of efficient antifouling and foul-releasing systems and summarize the main achievements with biocidal and nonbiocidal sol-gel coatings. We conclude by giving insight into the marine coatings and sol-gel products markets, providing arguments to justify our conclusion that the sol-gel coatings technology is now a mature platform for the development of economically viable and environmentally friendly antifouling and foul-release formulations of enhanced performance.

Control of Biofouling using Biodegradable Natural Products

DTIC Science & Technology

2002-10-01

Hydroxylated aromatic acids are also known fungicides. An example of this is the production of protocatechuic acid by Allium sativum (garlic). The...copper, zinc ), non-biodegradable, or difficult/costly to use (peroxides, ozone). In addition, the potential of unintentional negative impact on non

Treatment of Biofouling in Internal Seawater Systems - Phase 2

DTIC Science & Technology

2007-11-01

Denture Cleansing Tablets. Issue Date: Feb 2006. Reckitt Benckiser 12 In the first instance, in July 2006, mussels were transferred directly to an...Denture Cleansing Tablets (Reckit Benckiser , West Ryde) Chemical composition11: Potassium peroxymonosulfate 10-30% Sodium carbonate ᝺% Citric

Contribution of assimilable organic carbon to biological fouling in seawater reverse osmosis membrane treatment.

PubMed

Weinrich, Lauren; LeChevallier, Mark; Haas, Charles N

2016-09-15

Biological fouling occurs on RO membranes when bacteria and nutrients are present in conditions that are conducive to growth and proliferation of the bacteria. Controlling microbial growth on the membranes is typically limited to biocide application (i.e., disinfectants) in seawater RO plants. However, biological growth and subsequent fouling has not been well-managed. Pretreatment has not been focused on nutrient limitation. This project used a biological assay, the assimilable organic carbon (AOC) test to evaluate pretreatment effects on the nutrient supply. The AOC test provided a useful surrogate measurement for the biodegradability or biofouling potential of RO feed water. Biofouling observed in controlled conditions at the bench- and pilot-scale resulted in statistically significant correlations between AOC and the operational effects caused by biofouling. Membrane fouling rates are observed through operational changes over time such as increased differential pressure between the membrane feed and concentrate locations and decreased permeate flux through the membrane. In full scale plants there were strong correlations when AOC was used as a predictor variable for increased differential pressure (0.28-0.55 bar from September-December 2012) and decreased specific flux (1.40 L per hour/(m(2) · bar)). Increased differential pressure was associated with RO membrane biological fouling when the median AOC was 50 μg/L during pilot testing. Conditions were also evaluated at the bench-scale using a flat sheet RO membrane. In a comparison test using 30 and 1000 μg/L AOC, fouling was detected on more portions of the membrane when AOC was higher. Biofilm and bacterial deposits were apparent from scanning electron microscope imaging and biomass measurements using ATP. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of a hybrid ozonation biofilm-membrane filatration process for the production of drinking water.

PubMed

Leiknes, T; Lazarova, M; Odegaard, H

2005-01-01

Drinking water sources in Norway are characterized by high concentrations of natural organic matter (NOM), low alkalinity and low turbidity. The removal of NOM is therefore a general requirement in producing potable water. Drinking water treatment plants are commonly designed with coagulation direct filtration or NF spiral wound membrane processes. This study has investigated the feasibility and potential of a hybrid process combining ozonation and biofiltration with a rotating disk membrane for treating drinking water with high NOM concentrations. Ozonation will oxidize the NOM content removing colour and form biodegradable organic compounds, which can be removed in biological filters. A constructed water was used in this study which is representative of ozonated NOM-containing water. A rotating membrane disk bioreactor downstream the ozonation process was used to carry out both the biodegradation as well as biomass separation in the same reactor. Maintenance of biodegradation of the organic matter while controlling biofouling of the membrane and acceptable water production rates was the focus in the study. Three operating modes were investigated. Removal of the biodegradable organics was consistent throughout the study indicating that sufficient biomass was maintained in the reactor for all operating conditions tested. Biofouling control was not achieved through shear-induced cleaning by periodically rotating the membrane disks at high speed. By adding a small amount of sponges in the membrane chamber the biofouling could be controlled by mechanical cleaning of the membrane surface during disk rotation. The overall results indicate that the system can favorably be used in an ozonation/biofiltration process by carrying out both biodegradation as well as biomass separation in the same reactor.

Tight ceramic UF membrane as RO pre-treatment: the role of electrostatic interactions on phosphate rejection.

PubMed

Shang, Ran; Verliefde, Arne R D; Hu, Jingyi; Zeng, Zheyi; Lu, Jie; Kemperman, Antoine J B; Deng, Huiping; Nijmeijer, Kitty; Heijman, Sebastiaan G J; Rietveld, Luuk C

2014-01-01

Phosphate limitation has been reported as an effective approach to inhibit biofouling in reverse osmosis (RO) systems for water purification. The rejection of dissolved phosphate by negatively charged TiO2 tight ultrafiltration (UF) membranes (1 kDa and 3 kDa) was observed. These membranes can potentially be adopted as an effective process for RO pre-treatment in order to constrain biofouling by phosphate limitation. This paper focuses on electrostatic interactions during tight UF filtration. Despite the larger pore size, the 3 kDa ceramic membrane exhibited greater phosphate rejection than the 1 kDa membrane, because the 3 kDa membrane has a greater negative surface charge and thus greater electrostatic repulsion against phosphate. The increase of pH from 6 to 8.5 led to a substantial increase in phosphate rejection by both membranes due to increased electrostatic repulsion. At pH 8.5, the maximum phosphate rejections achieved by the 1 kDa and 3 kDa membrane were 75% and 86%, respectively. A Debye ratio (ratio of the Debye length to the pore radius) is introduced in order to evaluate double layer overlapping in tight UF membranes. Threshold Debye ratios were determined as 2 and 1 for the 1 kDa and 3 kDa membranes, respectively. A Debye ratio below the threshold Debye ratio leads to dramatically decreased phosphate rejection by tight UF membranes. The phosphate rejection by the tight UF, in combination with chemical phosphate removal by coagulation, might accomplish phosphate-limited conditions for biological growth and thus prevent biofouling in the RO systems. Copyright © 2013 Elsevier Ltd. All rights reserved.

Biofouling on Reservoir in Sea Water

NASA Astrophysics Data System (ADS)

Yoon, H.; Eom, C.; Kong, M.; Park, Y.; Chung, K.; Kim, B.

2011-12-01

The organisms which take part in marine biofouling are primarily the attached or sessile forms occurring naturally in the shallower water along the coast [1]. This is mainly because only those organisms with the ability to adapt to the new situations created by man can adhere firmly enough to avoid being washed off. Chemical and microbiological characteristics of the fouling biofilms developed on various surfaces in contact with the seawater were made. The microbial compositions of the biofilm communities formed on the reservoir polymer surfaces were tested for. The quantities of the diverse microorganisms in the biofilm samples developed on the prohibiting polymer reservoir surface were larger when there was no concern about materials for special selection for fouling. To confirm microbial and formation of biofilm on adsorbents was done CLSM (Multi-photon Confocal Laser Scanning Microscope system) analysis. Microbial identified using 16S rRNA. Experiment results, five species which are Vibrio sp., Pseudoalteromonas, Marinomonas, Sulfitobacter, and Alteromonas discovered to reservoir formed biofouling. There are some microorganism cause fouling and there are the others control fouling. The experimental results offered new specific information, concerning the problems in the application of new material as well as surface coating such as anti-fouling coatings. They showed the important role microbial activity in fouling and corrosion of the surfaces in contact with the any seawater. Acknowledgement : This research was supported by the national research project titled "The Development of Technology for Extraction of Resources Dissolved in Seawater" of the Korea Institute of Geoscience and Mineral Resources (KIGAM) funded by the Ministry of Land, Transport and Maritime Affairs. References [1] M. Y. Diego, K. Soren, and D. J. Kim. Prog. Org. Coat. 50, (2004) p.75-104.

GEOCHEMISTRY OF SUBSURFACE REACTIVE BARRIERS FOR REMEDIATION OF CONTAMINATED GROUND WATER

EPA Science Inventory

Reactive barriers that couple subsurface fluid flow with a passive chemical treatment zone are emerging, cost effective approaches for in-situ remediation of contaminated groundwater. Factors such as the build-up of surface precipitates, bio-fouling, and changes in subsurface tr...

CARBON AND SULFUR ACCUMULATION AND IRON MINERAL TRANSFORMATION IN PERMEABLE REACTIVE BARRIERS CONTAINING ZERO-VALENT IRON

EPA Science Inventory

Permeable reactive barrier technology is an in-situ approach for remediating groundwater contamination that combines subsurface fluid flow management with passive chemical treatment. Factors such as the buildup of mineral precipitates, buildup of microbial biomass (bio-fouling...

Antifouling and antibacterial polyketides from marine gorgonian coral-associated fungus Penicillium sp. SCSGAF 0023.

PubMed

Bao, Jie; Sun, Yu-Lin; Zhang, Xiao-Yong; Han, Zhuang; Gao, Hai-Chun; He, Fei; Qian, Pei-Yuan; Qi, Shu-Hua

2013-04-01

Two new polyketides, 6,8,5'6'-tetrahydroxy-3'-methylflavone (1) and paecilin C (2), together with six known analogs secalonic acid D (3), secalonic acid B (4) penicillixanthone A (5), emodin (6), citreorosein (7) and isorhodoptilometrin (8) were obtained from a broth of gorgonian coral-associated fungus Penicillium sp. SCSGAF 0023. Compounds 1 and 6-8 had significant antifouling activity against Balanus amphitrite larvae settlement with EC50 values of 6.7, 6.1, 17.9 and 13.7 μg ml(-1), respectively, and 3-5 showed medium antibacterial activity against four tested bacterial strains. This was the first report of antibacterial activity of 3-5 against marine bacteria and antifouling activity of 6-8 against marine biofouling organism's larvae. The results indicated that gorgonian coral-associated fungus Penicillium sp. SCSGAF 0023 strain could produce antifouling and antibacterial compounds that might aid the host gorgonian coral in protection against marine pathogen bacteria, biofouling organisms and other intruders.

Mitigating external and internal cathode fouling using a polymer bonded separator in microbial fuel cells.

PubMed

Yang, Wulin; Rossi, Ruggero; Tian, Yushi; Kim, Kyoung-Yeol; Logan, Bruce E

2018-02-01

Microbial fuel cell (MFC) cathodes rapidly foul when treating domestic wastewater, substantially reducing power production over time. Here a wipe separator was chemically bonded to an activated carbon air cathode using polyvinylidene fluoride (PVDF) to mitigate cathode fouling and extend cathode performance over time. MFCs with separator-bonded cathodes produced a maximum power density of 190 ± 30 mW m -2 after 2 months of operation using domestic wastewater, which was ∼220% higher than controls (60 ± 50 mW m -2 ) with separators that were not chemically bonded to the cathode. Less biomass (protein) was measured on the bonded separator surface than the non-bonded separator, indicating chemical bonding reduced external bio-fouling. Salt precipitation that contributed to internal fouling was also reduced using separator-bonded cathodes. Overall, the separator-bonded cathodes showed better performance over time by mitigating both external bio-fouling and internal salt fouling. Copyright © 2017 Elsevier Ltd. All rights reserved.

In vitro test systems supporting the development of improved pest control methods: a case study with chemical mixtures and bivalve biofoulers.

PubMed

Silva, Carlos; Nunes, Bruno; Nogueira, António Ja; Gonçalves, Fernando; Pereira, Joana L

2016-11-01

Using the bivalve macrofouler Corbicula fluminea, the suitability of in vitro testing as a stepping stone towards the improvement of control methods based on chemical mixtures was addressed in this study. In vitro cholinesterase (ChE) activity inhibition following single exposure of C. fluminea tissue to four model chemicals (the organophosphates dimethoate and dichlorvos, copper and sodium dodecyl phosphate [SDS]) was first assessed. Consequently, mixtures of dimethoate with copper and dichlorvos with SDS were tested and modelled; mixtures with ChE revealed synergistic interactions for both chemical pairs. These synergic combinations were subsequently validated in vivo and the increased control potential of these selected combinations was verified, with gains of up to 50% in C. fluminea mortality relative to corresponding single chemical treatments. Such consistency supports the suitability of using time- and cost-effective surrogate testing platforms to assist the development of biofouling control strategies incorporating mixtures.

In situ glass antifouling using Pt nanoparticle coating for periodic electrolysis of seawater

NASA Astrophysics Data System (ADS)

Xue, Yuxi; Zhao, Jin; Qiu, Ri; Zheng, Jiyong; Lin, Cunguo; Ma, Bojiang; Wang, Peng

2015-12-01

In situ electrochemical chlorination is a promising way to prohibit the biofouling on glass used for optical devices in seawater. To make this approach practical, a conductive glass should have low overpotential to generate Cl2, so that the electrical energy consumption, a critical issue for field application, will be low. Moreover, a long sustainability should also be taken into consideration from the application perspective. Following these criteria, we propose Pt/ITO surface to electrochemically generate Cl2, which immunizes biofouling for glass substrate. In this report, firstly, Pt nanoparticle/ITO is prepared via an electrodeposition approach. Secondly, electrocatalysis capability of Pt/ITO is elucidated, which shows the catalysis for Cl2 generation from NaCl solution and seawater has been sparked with Pt on the surface. Also, Pt/ITO is more sustainable and efficient than the bare ITO in natural seawater. Thirdly, the antifouling property is evaluated taking diatom as the target organism. Electrochemical chlorination on Pt/ITO can efficiently prevent the glass from fouling.

Biofouling behavior and performance of forward osmosis membranes with bioinspired surface modification in osmotic membrane bioreactor.

PubMed

Li, Fang; Cheng, Qianxun; Tian, Qing; Yang, Bo; Chen, Qianyuan

2016-07-01

Forward osmosis (FO) has received considerable interest for water and energy related applications in recent years. Biofouling behavior and performance of cellulose triacetate (CTA) forward osmosis membranes with bioinspired surface modification via polydopamine (PD) coating and poly (ethylene glycol) (PEG) grafting (PD-g-PEG) in a submerged osmotic membrane bioreactor (OMBR) were investigated in this work. The modified membranes exhibited lower flux decline than the pristine one in OMBR, confirming that the bioinspired surface modification improved the antifouling ability of the CTA FO membrane. The result showed that the decline of membrane flux related to the increase of the salinity and MLSS concentration of the mixed liquid. It was concluded that the antifouling ability of modified membranes ascribed to the change of surface morphology in addition to the improvement of membrane hydrophilicity. The bioinspired surface modifications might improve the anti-adhesion for the biopolymers and biocake. Copyright © 2016 Elsevier Ltd. All rights reserved.

Highly efficient non-biofouling coating of zwitterionic polymers: poly((3-(methacryloylamino)propyl)-dimethyl(3-sulfopropyl)ammonium hydroxide).

PubMed

Cho, Woo Kyung; Kong, Bokyung; Choi, Insung S

2007-05-08

This work describes the formation of highly efficient non-biofouling polymeric thin films of poly((3-(methacryloylamino)propyl)-dimethyl(3-sulfopropyl)ammonium hydroxide), (poly(MPDSAH)). The poly(MPDSAH) films were generated from the self-assembled monolayers terminating in an initiator of atom transfer radical polymerization (ATRP) by the surface-initiated ATRP of MPDSAH. The poly(MPDSAH) films on a gold surface were characterized by ellipsometry, FT-IR spectroscopy, contact angle goniometery, and X-ray photoelectron spectroscopy. The copper complexes and unpolymerized monomers trapped inside the polymer brushes were completely washed out by soaking the poly(MPDSAH)-coated substrate in water at 40 degrees C for 4 days. The amount of proteins nonspecifically adsorbed onto the poly(MPDSAH) films was evaluated by surface plasmon resonance spectroscopy: the adsorption of proteins was <0.6 ng/cm(2) on the surfaces for all the model proteins. The ability of the poly(MPDSAH) films to resist the nonspecific adsorption of proteins was comparable to that of the best known systems.

Succession and physiological health of freshwater microalgal fouling in a Tasmanian hydropower canal.

PubMed

Perkins, Kathryn J; Andrewartha, Jessica M; McMinn, Andrew; Cook, Suellen S; Hallegraeff, Gustaaf M

2010-08-01

Freshwater microalgal biofouling in hydropower canals in Tarraleah, Tasmania, is dominated by a single diatom species, Gomphonema tarraleahae. The microfouling community is under investigation with the aim of reducing its impact on electricity generation. Species succession was investigated using removable glass slides. Fouled slides were examined microscopically and for chlorophyll a biomass. Chl a biomass increased steeply after 8 weeks (0.09-0.87 mg m(-2)), but increased much earlier on slides surrounded by a biofouled inoculum. Succession began with low profile diatoms such as Tabellaria flocculosa, progressing to stalked diatoms such as Gomphonema spp. and Cymbella aspera. Few chlorophytes and no filamentous algae were present. Pulse amplitude modulated fluorometry was used to measure the physiological health of fouling on the canal wall. Maximum quantum yield (F(v)/F(m)) measurements were consistently <0.18, indicating that the fouling mat consisted of dead or dying algae. The succession and physiological health of cells in the fouling community has broad implications for mitigation techniques used.

Biofouling resistance of boron-doped diamond neural stimulation electrodes is superior to titanium nitride electrodes in vivo.

PubMed

Meijs, S; Alcaide, M; Sørensen, C; McDonald, M; Sørensen, S; Rechendorff, K; Gerhardt, A; Nesladek, M; Rijkhoff, N J M; Pennisi, C P

2016-10-01

The goal of this study was to assess the electrochemical properties of boron-doped diamond (BDD) electrodes in relation to conventional titanium nitride (TiN) electrodes through in vitro and in vivo measurements. Electrochemical impedance spectroscopy, cyclic voltammetry and voltage transient (VT) measurements were performed in vitro after immersion in a 5% albumin solution and in vivo after subcutaneous implantation in rats for 6 weeks. In contrast to the TiN electrodes, the capacitance of the BDD electrodes was not significantly reduced in albumin solution. Furthermore, BDD electrodes displayed a decrease in the VTs and an increase in the pulsing capacitances immediately upon implantation, which remained stable throughout the whole implantation period, whereas the opposite was the case for the TiN electrodes. These results reveal that BDD electrodes possess a superior biofouling resistance, which provides significantly stable electrochemical properties both in protein solution as well as in vivo compared to TiN electrodes.

Utilization of artificial recharged effluent as makeup water for industrial cooling system: corrosion and scaling.

PubMed

Wei, Liangliang; Qin, Kena; Zhao, Qingliang; Noguera, Daniel R; Xin, Ming; Liu, Chengcai; Keene, Natalie; Wang, Kun; Cui, Fuyi

2016-01-01

The secondary effluent from wastewater treatment plants was reused for industrial cooling water after pre-treatment with a laboratory-scale soil aquifer treatment (SAT) system. Up to a 95.3% removal efficiency for suspended solids (SS), 51.4% for chemical oxygen demand (COD), 32.1% for Cl(-) and 30.0% SO4(2-) were observed for the recharged secondary effluent after the SAT operation, which is essential for controlling scaling and corrosion during the cooling process. As compared to the secondary effluent, the reuse of the 1.5 m depth SAT effluent decreased the corrosion by 75.0%, in addition to a 55.1% decline of the scales/biofouling formation (with a compacted structure). The experimental results can satisfy the Chinese criterion of Design Criterion of the Industrial Circulating Cooling Water Treatment (GB 50050-95), and was more efficient than tertiary effluent which coagulated with ferric chloride. In addition, chemical structure of the scales/biofouling obtained from the cooling system was analyzed.

Propagule pressure determines recruitment from a commercial shipping pier.

PubMed

Hedge, Luke H; Johnston, Emma L

2012-01-01

Artificial structures associated with shipping and boating activities provide habitats for a diverse suite of non-indigenous marine species. Little is known about the proportion of invader success in nearby waters that is attributable to these structures. Areas close to piles, wharves and piers are likely to be exposed to increasing levels of propagule pressure, enhancing the recruitment of non-indigenous species. Recruitment of non-indigenous and native marine biofouling taxa were evaluated at different distances from a large commercial shipping pier. Since artificial structures also represent a desirable habitat for fish, how predation on marine invertebrates influences the establishment of non-indigenous and native species was also evaluated. The colonisation of several non-indigenous marine species declined rapidly with distance from the structure. Little evidence was found to suggest that predators have much influence on the colonisation success of marine sessile invertebrate species, non-indigenous or otherwise. It is suggested that propagule pressure, not predation, more strongly predicts establishment success in these biofouling assemblages.

Efficacy of humidity retention bags for the reduced adsorption and improved cleaning of tissue proteins including prion-associated amyloid to surgical stainless steel surfaces.

PubMed

Secker, T J; Pinchin, H E; Hervé, R C; Keevil, C W

2015-01-01

Increasing drying time adversely affects attachment of tissue proteins and prion-associated amyloid to surgical stainless steel, and reduces the efficacy of commercial cleaning chemistries. This study tested the efficacy of commercial humidity retention bags to reduce biofouling on surgical stainless steel and to improve subsequent cleaning. Surgical stainless steel surfaces were contaminated with ME7-infected brain homogenates and left to dry for 15 to 1,440 min either in air, in dry polythene bags or within humidity retention bags. Residual contamination pre/post cleaning was analysed using Thioflavin T/SYPRO Ruby dual staining and microscope analysis. An increase in biofouling was observed with increased drying time in air or in sealed dry bags. Humidity retention bags kept both protein and prion-associated amyloid minimal across the drying times both pre- and post-cleaning. Therefore, humidity bags demonstrate a cheap, easy to implement solution to improve surgical instrument reprocessing and to potentially reduce associated hospital acquired infections.

Physicochemical properties and membrane biofouling of extra-cellular polysaccharide produced by a Micrococcus luteus strain.

PubMed

Feng, Lei; Li, Xiufen; Song, Ping; Du, Guocheng; Chen, Jian

2014-07-01

The physicochemical properties of the extra-cellular polysaccharide (EPS) produced by a Micrococcus luteus strain, a dominating strain isolated from membrane biofouling layer, were determined in this study. The EPS isolated from this strain was measured to have an average molecular weight of 63,540 Da and some typical polysaccharide absorption peaks in Fourier transform infrared spectrum. Monosaccharide components of the EPS contained rhamnose, fucose, arabinose, xylose, mannose, galactose and glucose in a molar ratio of 0.2074:0.0454:0.0262:0.0446:1.7942:1.2086:0.4578. Pseudo plastic properties were also observed for the EPS through the rheological measurement. The EPS was further characterized for its behavior to cause membrane flux decline. The results showed that both flux declines for polyvinylidenefluoride (PVDF) and polypropylene membranes became more severe as EPS feed concentration increased. A higher irreversible fouling for the PVDF membrane suggested that the EPS had the larger fouling potential to this microfiltration membrane.

Tailoring the Surface Properties of Coatings Through Self-Stratification

DTIC Science & Technology

2016-10-13

34 Biofouling, 26 (8) 961-972 (2010) 16 lguerb, 0, Poleunis, C, Mazeas, F, Compere , C and Bertrand, P, "Antifouling Properties of Poly(methyl methacrylate...technologies. Woodhead Publishing Limited: Cambridge, UK, 2009. 13. lguerb, 0.; Poleunis, C. ; Mazeas, F.; Compere , C. ; Bertrand, P., Antifouling

Environmentally Benign and Permanent Modifications to Prevent Biofouling on Marine and Hydrokinetic Devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng Zhang

2012-04-19

Semprus Biosciences is developing environmentally benign and permanent modifications to prevent biofouling on Marine and Hydrokinetic (MHK) devices. Biofouling, including growth on external surfaces by bacteria, algae, barnacles, mussels, and other marine organisms, accumulate quickly on MHK devices, causing mechanical wear and changes in performance. Biofouling on crucial components of hydrokinetic devices, such as rotors, generators, and turbines, imposes substantial mass and hydrodynamic loading with associated efficiency loss and maintenance costs. Most antifouling coatings leach toxic ingredients, such as copper and tributyltin, through an eroding process, but increasingly stringent regulation of biocides has led to interest in the development ofmore » non-biocidal technologies to control fouling. Semprus Biosciences research team is developing modifications to prevent fouling from a broad spectrum of organisms on devices of all shapes, sizes, and materials for the life of the product. The research team designed and developed betaine-based polymers as novel underwater coatings to resist the attachment of marine organisms. Different betaine-based monomers and polymers were synthesized and incorporated within various coating formulations. The formulations and application methods were developed on aluminum panels with required adhesion strength and mechanical properties. The coating polymers were chemically stable under UV, hydrolytic and oxidative environments. The sulfobetaine formulations are applicable as nonleaching and stable underwater coatings. For the first time, coating formulations modified with highly packed sulfobetaine polymers were prepared and demonstrated resistance to a broad spectrum of marine organisms. Assays for comparing nonfouling performance were developed to evaluate protein adsorption and bacteria attachment. Barnacle settlement and removal were evaluated and a 60-day field test was performed. Silicone substrates including a commercial fouling release coating were used for comparison. Compared with the unmodified silicone substrates, the sulfobetaine-modified formulations were able to exhibit a 98% reduction in fibrinogen adsorption, 97.0% (E. coli), 99.6% (S. aureus), and 99.5% (C. lytica) reduction in bacteria attachment, and 100% reduction in barnacles cyprid attachment. In addition to the significant improvement in fouling resistance of various organisms, the 60-day field test also showed an evident efficacy from visual assessment, foul rating, and fouling removal test. The research confirmed that the novel antifouling mechanism of betaine polymers provides a new avenue for marine coating development. The developed coatings out-performed currently used nontoxic underwater coatings in a broad spectrum of fouling resistance. By further developing formulations and processing methods for specific devices, the technology is ready for the next stage of development with demonstration in MHK systems.« less

Effect of sediment settling on controlling golden mussel invasion in water transfer project

NASA Astrophysics Data System (ADS)

Xu, Mengzhen; Wang, Zhaoyin; Bogen, Jim; Pan, Baozhu

2013-04-01

Inter-basin water transfer projects have been widely used to solve uneven distribution of water resources and water shortage in China. Along with the transferring of water resources, golden mussel (Limnoperna fortunei), the filter-collector macro-invertebrate species originating from southern China has also been inadvertently transferred to new aquatic environment, resulting in quick and uncontrolled spread of the species. The golden mussels are invasive by nature and endowed with a strong byssus for attaching onto their habitat, allowing them to easily invade natural and artificial aquatic systems, which was resulted in high-density golden mussel attachment that causes serious bio-fouling. Invasion and bio-fouling by golden mussels in water transfer systems has drawn attention widely because it has resulted in high resistance to water flow, corrosion of pipe walls and even clogging of tunnels, as well as causing water pollution and ecological imbalance in the regions that receive water infested with golden mussels. Field investigation was conducted along the East River, which is the main drinking water resource for Cantong province and Hongkong, China, to study the natural habitats of golden mussels. Surveys of water transfer tunnels which carry water from the East River to several big cities in Cantong province were done to study golden mussel invasion and attachment in tunnels. It is found that in the natural habitat, golden mussels mainly attach to bedrock and bank stones and solid surfaces facing upstream, while no golden mussels are attached on the surfaces facing downstream and suffering sediment deposition. In the water transfer tunnels, golden mussel attachment densities of 40,000 individuals/m2 mainly occurred on the portion of tunnel walls which face downwards and thus avoid sedimentation. An experiment was designed to study the effect of sediment settling on golden mussel attachment. The results showed that settling of fine sediment particles affects golden mussels by preventing them from filtering food and oxygen from water, and in this way killing them. The attachment density decreased with increased sediment deposition. Golden mussel density decreased by about 70-90% when the sedimentation rate increased by 3-6 times. Therefore, spraying with fine sediment or creating hyper-concentration of sediment water to treat golden mussels before they enter tunnels is recommended as an effective strategy for controlling golden mussel invasion and high-density bio-fouling. Key words: golden mussel invasion; bio-fouling; sediment settling; habitat; controlling strategy

Emerging investigators series: prospects and challenges for high-pressure reverse osmosis in minimizing concentrated waste streams

DOE PAGES

Schantz, A. Benjamin; Xiong, Boya; Dees, Elizabeth; ...

2018-01-01

If challenges such as mechanical stability, scaling, biofouling and concentration polarization at high pressures are addressed, high-pressure RO could be used to efficiently remove water from high-salinity waste brines as part of a zero-liquid-discharge disposal process.

ALTERNATIVES TO CHLORINATION FOR CONTROL OF CONDENSER TUBE BIO-FOULING

EPA Science Inventory

The report gives results of a study of methods used to reduce free-chlorine residuals in power plant effluents. Most U.S. power plants use chlorine (28,600 tons in 1972) to control biological fouling in their cooling systems, particularly in their condenser tubes. Using chlorine ...

Emerging investigators series: prospects and challenges for high-pressure reverse osmosis in minimizing concentrated waste streams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schantz, A. Benjamin; Xiong, Boya; Dees, Elizabeth

If challenges such as mechanical stability, scaling, biofouling and concentration polarization at high pressures are addressed, high-pressure RO could be used to efficiently remove water from high-salinity waste brines as part of a zero-liquid-discharge disposal process.

Marine biomass: New York State species and site studies. Annual report December 1982-November 1983

DOE Office of Scientific and Technical Information (OSTI.GOV)

McKay, L.B.

1983-11-01

The Energy Authority has been conducting tests since 1979 in an effort to develop a feasible system for the production in Long Island Sound of marine biomass from indigenous macroalgae for economically competitive conversion to synthetic natural gas. During 1983 this goal was brought closer to realization when a 120 x 41 foot seaweed test farm was placed in 60 feet of water in Long Island Sound. The structure is basically a flexible wire cable and rope grid, buoyed at the surface and moored to the bottom of the Sound. It is suitable for cultivating seaweeds that attach themselves tomore » surfaces such as the brown kelp, Laminaria saccharina. The test farm design was chosen from among four previously developed by the engineering team. An ongoing program is taking place in Long Island Sound to test the strength of the structure and to obtain information on plants growing in the structure. The program will test the strain on the lines, corrosion on metal parts, and available light and temperature at various times. Also, since 1982, bioengineering tests have focused on biofouling experiments, and seaweed and rope strength tests. The report also includes discussion of a laboratory research program focused on seeding techniques and strain selection.« less

Calibration of Passive Samplers for the Monitoring of Pharmaceuticals in Water-Sampling Rate Variation.

PubMed

Męczykowska, Hanna; Kobylis, Paulina; Stepnowski, Piotr; Caban, Magda

2017-05-04

Passive sampling is one of the most efficient methods of monitoring pharmaceuticals in environmental water. The reliability of the process relies on a correctly performed calibration experiment and a well-defined sampling rate (R s ) for target analytes. Therefore, in this review the state-of-the-art methods of passive sampler calibration for the most popular pharmaceuticals: antibiotics, hormones, β-blockers and non-steroidal anti-inflammatory drugs (NSAIDs), along with the sampling rate variation, were presented. The advantages and difficulties in laboratory and field calibration were pointed out, according to the needs of control of the exact conditions. Sampling rate calculating equations and all the factors affecting the R s value - temperature, flow, pH, salinity of the donor phase and biofouling - were discussed. Moreover, various calibration parameters gathered from the literature published in the last 16 years, including the device types, were tabled and compared. What is evident is that the sampling rate values for pharmaceuticals are impacted by several factors, whose influence is still unclear and unpredictable, while there is a big gap in experimental data. It appears that the calibration procedure needs to be improved, for example, there is a significant deficiency of PRCs (Performance Reference Compounds) for pharmaceuticals. One of the suggestions is to introduce correction factors for R s values estimated in laboratory conditions.

INFLUENCE OF GROUNDWATER GEOCHEMISTRY ON THE LONG-TERM PERFORMANCE OF IN-SITU PERMEABLE REACTIVE BARRIERS CONTAINING ZERO-VALENT IRON

EPA Science Inventory

Reactive barriers that couple subsurface fluid flow with a passive chemical treatment zone are emerging, cost effective approaches for in-situ remediation of contaminated groundwater. Factors such as the build-up of surface precipitates, bio-fouling, and changes in subsurface tr...

Underground UXO: Are They a Significant Source of Explosives in Soil Compared to Low- and High-Order Detonations

DTIC Science & Technology

2004-12-01

steel in marine environments. Biofouling, 15(1– 3): 37–47. Videla, H.A. (2002) Prevention and control of biocorrosion . International Bio- deterioration...Prevention and control of biocorrosion . International Bio- deterioration and Biodegradation, 49(4): 259–270. Virtanen, S., and M. Buchler (2003

Method and Apparatus for Preventing Biofouling of Surfaces

DTIC Science & Technology

2011-06-14

ammonium compounds that are suitable for this purpose include benzalkonium chloride , benzethonium chloride , methylbenzethonium chloride , cetalkonium... chloride , cetylpyridinium chloride , cetrimonium, cetrimide, dofanium chloride , tetraethylammonium bromide, didecyldimethylammonium chloride and domiphen...upon layers of impermeable nano-particles cause diffusing molecules to follow a tortuous, 8 slow path that results in a huge reduction in

A method for rapid quantitative assessment of biofilms with biomolecular staining and image analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larimer, Curtis J.; Winder, Eric M.; Jeters, Robert T.

Here, the accumulation of bacteria in surface attached biofilms, or biofouling, can be detrimental to human health, dental hygiene, and many industrial processes. A critical need in identifying and preventing the deleterious effects of biofilms is the ability to observe and quantify their development. Analytical methods capable of assessing early stage fouling are cumbersome or lab-confined, subjective, and qualitative. Herein, a novel photographic method is described that uses biomolecular staining and image analysis to enhance contrast of early stage biofouling. A robust algorithm was developed to objectively and quantitatively measure surface accumulation of Pseudomonas putida from photographs and results weremore » compared to independent measurements of cell density. Results from image analysis quantified biofilm growth intensity accurately and with approximately the same precision of the more laborious cell counting method. This simple method for early stage biofilm detection enables quantifiable measurement of surface fouling and is flexible enough to be applied from the laboratory to the field. Broad spectrum staining highlights fouling biomass, photography quickly captures a large area of interest, and image analysis rapidly quantifies fouling in the image.« less

Biofouling: A critical consideration for evaluating in situ biotreatment feasibility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaufman, K.A.

1995-09-01

It is recognized by the EPA and many state and local regulatory agencies that in situ bioremedial treatment can be a technically sound and highly cost-effective method for the mitigation of soil and groundwater contamination, and numerous case histories corroborate this belief. Though not widely publicized (for understandable reasons), notable failures of similar treatment attempts can be traced to the consequences of biofouling, resultant from the inappropriate use of in situ treatment technologies. Such consequences can be related to the development of anaerobiosis due to inadequate diffusion of bioavailable oxygen to allow for aerobic metabolism within the contaminated soil matrix.more » Appropriate engineering and hydrogeological considerations of a site`s compatibility with in situ treatment requirements prior to process initiation can preclude the potential for the generation of noxious and/or toxic/explosive gases, as well as toxic endproducts of anaerobic microbial metabolism. Appropriate utilization of hydrogen peroxide, taking into account for the requirement for the enzyme catalase, and the biotoxic nature of hydrogen peroxide to many microorganisms, can minimize the deleterious effects of anaerobiosis and enhance oxidative bioremedial activity.« less

A method for rapid quantitative assessment of biofilms with biomolecular staining and image analysis

DOE PAGES

Larimer, Curtis J.; Winder, Eric M.; Jeters, Robert T.; ...

2015-12-07

Here, the accumulation of bacteria in surface attached biofilms, or biofouling, can be detrimental to human health, dental hygiene, and many industrial processes. A critical need in identifying and preventing the deleterious effects of biofilms is the ability to observe and quantify their development. Analytical methods capable of assessing early stage fouling are cumbersome or lab-confined, subjective, and qualitative. Herein, a novel photographic method is described that uses biomolecular staining and image analysis to enhance contrast of early stage biofouling. A robust algorithm was developed to objectively and quantitatively measure surface accumulation of Pseudomonas putida from photographs and results weremore » compared to independent measurements of cell density. Results from image analysis quantified biofilm growth intensity accurately and with approximately the same precision of the more laborious cell counting method. This simple method for early stage biofilm detection enables quantifiable measurement of surface fouling and is flexible enough to be applied from the laboratory to the field. Broad spectrum staining highlights fouling biomass, photography quickly captures a large area of interest, and image analysis rapidly quantifies fouling in the image.« less

Nanotechnology applications to desalination : a report for the joint water reuse & desalination task force.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brady, Patrick Vane; Mayer, Tom; Cygan, Randall Timothy

2011-01-01

Nanomaterials and nanotechnology methods have been an integral part of international research over the past decade. Because many traditional water treatment technologies (e.g. membrane filtration, biofouling, scale inhibition, etc.) depend on nanoscale processes, it is reasonable to expect one outcome of nanotechnology research to be better, nano-engineered water treatment approaches. The most immediate, and possibly greatest, impact of nanotechnology on desalination methods will likely be the development of membranes engineered at the near-molecular level. Aquaporin proteins that channel water across cell membranes with very low energy inputs point to the potential for dramatically improved performance. Aquaporin-laced polymer membranes and aquaporin-mimickingmore » carbon nanotubes and metal oxide membranes developed in the lab support this. A critical limitation to widespread use of nanoengineered desalination membranes will be their scalability to industrial fabrication processes. Subsequent, long-term improvements in nanoengineered membranes may result in self-healing membranes that ideally are (1) more resistant to biofouling, (2) have biocidal properties, and/or (3) selectively target trace contaminants.« less

Protein interactions with subcutaneously implanted biosensors.

PubMed

Gifford, Raeann; Kehoe, Joseph J; Barnes, Sandra L; Kornilayev, Boris A; Alterman, Michail A; Wilson, George S

2006-04-01

Biofouling of in vivo glucose sensors has been indicated as the primary reason for sensitivity losses observed during the first 24 h after implant [Wisniewski N, Moussy F, Reichert WM. Characterization of implantable biosensor membrane biofouling. Fresen J Anal Chem 2000; 366(6-7): 611-621]. Identification of the biomolecules that contribute to these sensitivity perturbations is the primary objective of the research presented. Active needle-type glucose sensors were implanted in Sprague-Dawley rats for 24h, and then a proteomics approach was used to identify the substances absorbed to the sensors. MALDI-TOF mass spectrometry was the primary tool utilized to identify the biomolecules in sensor leachate samples and species absorbed directly on sensor membranes excised from explanted in vivo sensors. Not surprisingly serum albumin was identified as the primary biomolecule present, however, predominantly as endogenous fragments of the protein. In addition, several other biomolecule fragments, mainly less than 15 kD, were identified. Based on these findings, it is concluded that fragments of larger biomolecules infiltrate the sensor membranes causing diminished glucose diffusivity, thus decreasing in vivo sensitivity.

Improved antifouling properties and selective biofunctionalization of stainless steel by employing heterobifunctional silane-polyethylene glycol overlayers and avidin-biotin technology

PubMed Central

Hynninen, Ville; Vuori, Leena; Hannula, Markku; Tapio, Kosti; Lahtonen, Kimmo; Isoniemi, Tommi; Lehtonen, Elina; Hirsimäki, Mika; Toppari, J. Jussi; Valden, Mika; Hytönen, Vesa P.

2016-01-01

A straightforward solution-based method to modify the biofunctionality of stainless steel (SS) using heterobifunctional silane-polyethylene glycol (silane-PEG) overlayers is reported. Reduced nonspecific biofouling of both proteins and bacteria onto SS and further selective biofunctionalization of the modified surface were achieved. According to photoelectron spectroscopy analyses, the silane-PEGs formed less than 10 Å thick overlayers with close to 90% surface coverage and reproducible chemical compositions. Consequently, the surfaces also became more hydrophilic, and the observed non-specific biofouling of proteins was reduced by approximately 70%. In addition, the attachment of E. coli was reduced by more than 65%. Moreover, the potential of the overlayer to be further modified was demonstrated by successfully coupling biotinylated alkaline phosphatase (bAP) to a silane-PEG-biotin overlayer via avidin-biotin bridges. The activity of the immobilized enzyme was shown to be well preserved without compromising the achieved antifouling properties. Overall, the simple solution-based approach enables the tailoring of SS to enhance its activity for biomedical and biotechnological applications. PMID:27381834

Contribution of Charges in Polyvinyl Alcohol Networks to Marine Antifouling.

PubMed

Yang, Wufang; Lin, Peng; Cheng, Daocang; Zhang, Longzhou; Wu, Yang; Liu, Yupeng; Pei, Xiaowei; Zhou, Feng

2017-05-31

Semi-interpenetrated polyvinyl alcohol polymer networks (SIPNs) were prepared by integrating various charged components into polyvinyl alcohol polymer. Contact angle measurement, attenuated total reflection Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and tensile tests were used to characterize the physicochemical properties of the prepared SIPNs. To investigate the contribution of charges to marine antifouling, the adhesion behaviors of green algae Dunaliella tertiolecta and diatoms Navicula sp. in the laboratory and of the actual marine animals in field test were studied for biofouling assays. The results suggest that less algae accumulation densities are observed for neutral-, anionic-, and zwitterionic-component-integrated SIPNs. However, for the cationic SIPNs, despite the hydration shell induced by the ion-dipole interaction, the resistance to biofouling largely depends on the amount of cationic component because of the possible favorable electrostatic attraction between the cationic groups in SIPNs and the negatively charged algae. Considering that the preparation of novel nontoxic antifouling coating is a long-standing and cosmopolitan industrial challenge, the SIPNs may provide a useful reference for marine antifouling and some other relevant fields.

Improved antifouling properties and selective biofunctionalization of stainless steel by employing heterobifunctional silane-polyethylene glycol overlayers and avidin-biotin technology

NASA Astrophysics Data System (ADS)

Hynninen, Ville; Vuori, Leena; Hannula, Markku; Tapio, Kosti; Lahtonen, Kimmo; Isoniemi, Tommi; Lehtonen, Elina; Hirsimäki, Mika; Toppari, J. Jussi; Valden, Mika; Hytönen, Vesa P.

2016-07-01

A straightforward solution-based method to modify the biofunctionality of stainless steel (SS) using heterobifunctional silane-polyethylene glycol (silane-PEG) overlayers is reported. Reduced nonspecific biofouling of both proteins and bacteria onto SS and further selective biofunctionalization of the modified surface were achieved. According to photoelectron spectroscopy analyses, the silane-PEGs formed less than 10 Å thick overlayers with close to 90% surface coverage and reproducible chemical compositions. Consequently, the surfaces also became more hydrophilic, and the observed non-specific biofouling of proteins was reduced by approximately 70%. In addition, the attachment of E. coli was reduced by more than 65%. Moreover, the potential of the overlayer to be further modified was demonstrated by successfully coupling biotinylated alkaline phosphatase (bAP) to a silane-PEG-biotin overlayer via avidin-biotin bridges. The activity of the immobilized enzyme was shown to be well preserved without compromising the achieved antifouling properties. Overall, the simple solution-based approach enables the tailoring of SS to enhance its activity for biomedical and biotechnological applications.

Metagenomes reveal microbial structures, functional potentials, and biofouling-related genes in a membrane bioreactor.

PubMed

Ma, Jinxing; Wang, Zhiwei; Li, Huan; Park, Hee-Deung; Wu, Zhichao

2016-06-01

Metagenomic sequencing was used to investigate the microbial structures, functional potentials, and biofouling-related genes in a membrane bioreactor (MBR). The results showed that the microbial community in the MBR was highly diverse. Notably, function analysis of the dominant genera indicated that common genes from different phylotypes were identified for important functional potentials with the observation of variation of abundances of genes in a certain taxon (e.g., Dechloromonas). Despite maintaining similar metabolic functional potentials with a parallel full-scale conventional activated sludge (CAS) system due to treating the identical wastewater, the MBR had more abundant nitrification-related bacteria and coding genes of ammonia monooxygenase, which could well explain its excellent ammonia removal in the low-temperature period. Furthermore, according to quantification of the genes involved in exopolysaccharide and extracellular polymeric substance (EPS) protein metabolism, the MBR did not show a much different potential in producing EPS compared to the CAS system, and bacteria from the membrane biofilm had lower abundances of genes associated with EPS biosynthesis and transport compared to the activated sludge in the MBR.

Gold nanoparticles and polyethylene glycols functionalized conducting polyaniline nanowires for ultrasensitive and low fouling immunosensing of alpha-fetoprotein.

PubMed

Hui, Ni; Sun, Xiaotian; Song, Zhiling; Niu, Shuyan; Luo, Xiliang

2016-12-15

An ultrasensitive biosensor for alpha-fetoprotein was developed based on electrochemically synthesized polyaniline (PANI) nanowires, which were functionalized with gold nanoparticles (AuNPs) and polyethylene glycols (PEG). The prepared PEG/AuNPs/PANI composite, combining the electrical conductivity of the AuNPs/PANI with the robust antifouling ability of PEG, offered an ideal substrate for the development of low fouling electrochemical biosensors. Alpha-fetoprotein (AFP), a well-known hepatocellular carcinoma biomarker, was used as a model analyte, and its antibody was immobilized on the PEG/AuNPs/PANI for the construction of the AFP immunosensor. Using the redox current of PANI as the sensing signal, in addition to the good biocompatibility of PEG/AuNPs and the anti-biofouling property of PEG, the developed immunosensor showed improved biosensing performances, such as wide linear range and ultralow detection limit (0.007pgmL(-1)). More importantly, it is label-free, reagentless and low fouling, making it capable of assaying AFP in real serum samples without suffering from significant interference or biofouling. Copyright © 2016 Elsevier B.V. All rights reserved.

Optimizing Micromixer Surfaces To Deter Biofouling.

PubMed

Waters, James T; Liu, Ya; Li, Like; Balazs, Anna C

2018-03-07

Using computational modeling, we show that the dynamic interplay between a flowing fluid and the appropriately designed surface relief pattern can inhibit the fouling of the substrate. We specifically focus on surfaces that are decorated with three-dimensional (3D) chevron or sawtooth "micromixer" patterns and model the fouling agents (e.g., cells) as spherical microcapsules. The interaction between the imposed shear flow and the chevrons on the surface generates 3D vortices in the system. We pinpoint a range of shear rates where the forces from these vortices can rupture the bonds between the two mobile microcapsules near the surface. Notably, the patterned surface offers fewer points of attachment than a flat substrate, and the shear flows readily transport the separated capsules away from the layer. We contrast the performance of surfaces that encompass rectangular posts, chevrons, and asymmetric sawtooth patterns and thereby identify the geometric factors that cause the sawtooth structure to be most effective at disrupting the bonding between the capsules. By breaking up nascent clusters of contaminant cells, these 3D relief patterns can play a vital role in disrupting the biofouling of surfaces immersed in flowing fluids.

Potential radiation control of biofouling bacteria on intake filters

NASA Astrophysics Data System (ADS)

Eichholz, Geoffrey G.; Jones, Cynthia G.; Haynes, Harold E.

The biofouling of filters at deep wells supplying water for industrial and drinking water purposes by various iron- and sulfur-reducing bacteria is a wide-spread problem in the United States and can cause serious economic losses. Among the means of control, steam heating or chemical additives can be applied only intermittently and have their own environmental impact. Preliminary studies have shown that installation of a sealed gamma radiation source may provide an alternative solution. Analysis of a range of water samples from contaminated wells identified many of the samples as rich in barsiderocapsa and barpseudomona bacteria. Static and dynamic experiments on water samples at various does and dose rates have shown that these organisms are relatively radiation-sensitive, with a lethal dose in the range of 200-400Gy (20-40kR). Since the main objective is to restrict growth or deposit of plaque on filters, dose rates of the order of 50-75 Gy/hr would be adequate. Such dose rates could be obtained with relatively weak sources, depending on filter dimensions. A conceptual design for such systems has been proposed.

Effects of prolonged entanglement in discarded fishing gear with substantive biofouling on the health and behavior of an adult shortfin mako shark, Isurus oxyrinchus.

PubMed

Wegner, Nicholas C; Cartamil, Daniel P

2012-02-01

A mature male shortfin mako, Isurus oxyrinchus, was captured with a three-strand twisted natural fiber rope wrapped around the body causing deep abrasions, scoliosis of the back, and undernourishment. Fifty-two pelagic peduculate barnacles from four species were found fouling on the rope. Assuming larval settlement occurred following entanglement, barnacle growth-rate data suggest the rope had been around the shark for at least 150 days. However, the onset of severe scoliosis (likely linked to the increased constriction of the rope with growth and the added drag induced by biofouling) indicates that this rope may have been in place much longer. Following removal of the rope, a pop-up satellite archival tag was attached to the shark to assess post-release health. The resulting 54 days of tag deployment data show that despite its injuries, the shark survived, and following an initial stress period, exhibited movement patterns characteristic of healthy makos. Copyright © 2011 Elsevier Ltd. All rights reserved.

Micro- and nanotechnologies in plankton research

NASA Astrophysics Data System (ADS)

Mohammed, Javeed Shaikh

2015-05-01

A better understanding of the vast range of plankton and their interactions with the marine environment would allow prediction of their large-scale impact on the marine ecosystem, and provide in-depth knowledge on pollution and climate change. Numerous technologies, especially lab-on-a-chip microsystems, are being used to this end. Marine biofouling is a global issue with significant economic consequences. Ecofriendly polymer nanotechnologies are being developed to combat marine biofouling. Furthermore, nanomaterials hold great potential for bioremediation and biofuel production. Excellent reviews covering focused topics in plankton research exist, with only a handful discussing both micro- and nanotechnologies. This work reviews both micro- and nanotechnologies applied to broad-ranging plankton research topics including flow cytometry, chemotaxis/toxicity assays, biofilm formation, marine antifouling/fouling-release surfaces and coatings, green energy, green nanomaterials, microalgae immobilization, and bioremediation. It is anticipated that developments in plankton research will see engineered exploitation of micro- and nanotechnologies. The current review is therefore intended to promote micro-/nanotechnology researchers to team up with limnologists/oceanographers, and develop novel strategies for understanding and green exploitation of the complex marine ecosystem.

Surface energy modification for biomedical material by corona streamer plasma processing to mitigate bacterial adhesion

NASA Astrophysics Data System (ADS)

Alhamarneh, Ibrahim; Pedrow, Patrick

2011-10-01

Bacterial adhesion initiates biofouling of biomedical material but the processes can be reduced by adjusting the material's surface energy. The surface of surgical-grade 316L stainless steel (316L SS) had its hydrophilic property enhanced by processing in a corona streamer plasma reactor using atmospheric pressure Ar mixed with O2. Reactor excitation was 60 Hz ac high-voltage (<= 10 kV RMS) applied to a multi-needle-to-grounded-torus electrode configuration. Applied voltage and streamer current pulses were monitored with a broadband sensor system. When Ar/O2 plasma was used, the surface energy was enhanced more than with Ar plasma alone. Composition of the surface before and after plasma treatment was characterized by XPS. As the hydrophilicity of the treated surface increased so did percent of oxygen on the surface thus we concluded that reduction in contact angle was mainly due to new oxygen-containing functionalities. FTIR was used to identify oxygen containing groups on the surface. The aging effect that accompanies surface free energy adjustments was also observed.

Transport of microplastics in coastal seas

NASA Astrophysics Data System (ADS)

Zhang, Hua

2017-12-01

Microplastic pollution of the marine environment has received increasing attention from scientists, the public, and policy makers over the last few years. Marine microplastics predominantly originate near the coast and can remain in the nearshore zone for some time. However, at present, there is little understanding of the fate and transport of microplastics in coastal regions. This paper provides a comprehensive overview of the physical processes involved in the movement of microplastics from estuaries to the continental shelf. The trajectory and speed of microplastics are controlled by their physical characteristics (density, size, and shape) and ocean dynamic conditions (wind, waves, tides, thermohaline gradients, and the influence of benthic sediments). Microplastic particles can be subjected to beaching, surface drifting, vertical mixing, and biofouling, as well as bed-load and suspended load transport processes, until reaching terminal deposition on beaches, in coastal marshes, in benthic sediments or until they are carried by ocean currents to subtropical convergence zones. The dynamic interaction of released microplastics with the shoreline is regulated by onshore/offshore transport, which is impacted by the source location as well as the geometry, vegetation, tidal regime, and wave direction. Wind and wave conditions dominate surface drifting of buoyant particles through Ekman drift, windage, and Stokes drift mechanisms. Neustic microplastic particles travel in the subsurface because of vertical mixing through wind-driven Langmuir circulation and heat cycling. Increasing accumulation of microplastics in benthic sediments needs to be quantitatively explored in terms of biofouling, deposition, entrainment, and transport dynamics. Further studies are required to understand the following: 1) the primary parameters (e.g., windage, terminal velocity, diffusivity, critical shear stress) that determine microplastic transport in different pathways; 2) dynamic distribution of microplastics in various coastal landscapes (e.g., wetlands, beaches, estuaries, lagoons, barrier islands, depocenters) regulated by hydrodynamic conditions; and 3) interactions between the physical transport processes and biochemical reactions (degradation, flocculation, biofouling, ingestions).

Carapace surface architecture facilitates camouflage of the decorator crab Tiarinia cornigera.

PubMed

Sanka, Immanuel; Suyono, Eko Agus; Rivero-Müller, Adolfo; Alam, Parvez

2016-09-01

This paper elucidates the unique setal morphology of the decorator crab Tiarinia cornigera, and further presents evidence to that setal morphology promotes micro-organism nucleation and adhesion. The carapace of this crab is covered by clusters of setae, each comprising a hollow acicular stem that is enveloped by a haystack-like structure. Using computational fluid dynamics, we find that these setae are responsible for manipulating water flow over the carapace surface. Micro-organisms in the sea water, nest in areas of flow stagnation and as a result, nucleate to and biofoul the setae by means of chemical adhesion. Attached micro-organisms secrete extracellular polymeric substances, which we deduce must also provide an additional element of chemical adhesion to mechanically interlocked mesoscopic and macroscopic biomatter. By coupling physical and chemical methods for adhesion, T. cornigera is able to hierarchically decorate its carapace. Our paper brings to light the unique decorator crab carapace morphology of T. cornigera; and furthermore evidences its function in micro-organism nucleation and adhesion. We show how this special carapace morphology directs and guides water flow to form nesting regions of water stagnation where micro-organisms can nucleate and adhere. In the literature, decorator crab carapaces are presumed to be able to mechanically interlock biomatter as camouflage using hook-like setal outgrowths. T. cornigera contrarily exhibits clusters of hay-stack like structures. By encouraging micro-organism adhesion to the carapace setae, T. cornigera is able to effectively attach biomatter using both chemical and physical principles of adhesion. T. cornigera essentially has a super-biofouling carapace surface, for at least micro-organisms. Our work will have an impact on researchers interested in biofouling, adhesion, biomedical and purification filter systems, and in the development of novel biomimetic surfaces with tailored properties. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Byssus Structure and Protein Composition in the Highly Invasive Fouling Mussel Limnoperna fortunei

PubMed Central

Li, Shiguo; Xia, Zhiqiang; Chen, Yiyong; Gao, Yangchun; Zhan, Aibin

2018-01-01

Biofouling mediated by byssus adhesion in invasive bivalves has become a global environmental problem in aquatic ecosystems, resulting in negative ecological and economic consequences. Previous studies suggested that mechanisms responsible for byssus adhesion largely vary among bivalves, but it is poorly understood in freshwater species. Understanding of byssus structure and protein composition is the prerequisite for revealing these mechanisms. Here, we used multiple methods, including scanning electron microscope, liquid chromatography–tandem mass spectrometry, transcriptome sequencing, real-time quantitative PCR, inductively coupled plasma mass spectrometry, to investigate structure, and protein composition of byssus in the highly invasive freshwater mussel Limnoperna fortunei. The results indicated that the structure characteristics of adhesive plaque, proximal and distal threads were conducive to byssus adhesion, contributing to the high biofouling capacity of this species. The 3,4-dihydroxyphenyl-α-alanine (Dopa) is a major post-transnationally modification in L. fortunei byssus. We identified 16 representative foot proteins with typical repetitive motifs and conserved domains by integrating transcriptomic and proteomic approaches. In these proteins, Lfbp-1, Lffp-2, and Lfbp-3 were specially located in foot tissue and highly expressed in the rapid byssus formation period, suggesting the involvement of these foot proteins in byssus production and adhesion. Multiple metal irons, including Ca2+, Mg2+, Zn2+, Al3+, and Fe3+, were abundant in both foot tissue and byssal thread. The heavy metals in these irons may be directly accumulated by L. fortunei from surrounding environments. Nevertheless, some metal ions (e.g., Ca2+) corresponded well with amino acid preferences of L. fortunei foot proteins, suggesting functional roles of these metal ions by interacting with foot proteins in byssus adhesion. Overall, this study provides structural and molecular bases of adhesive mechanisms of byssus in L. fortunei, and findings here are expected to develop strategies against biofouling by freshwater organisms. PMID:29713291

Immobilization and Stabilization of Acylase on Carboxylated Polyaniline Nanofibers for Highly Effective Antifouling Application via Quorum Quenching.

PubMed

Lee, Jeongjoon; Lee, Inseon; Nam, Jahyun; Hwang, Dong Soo; Yeon, Kyung-Min; Kim, Jungbae

2017-05-10

Acylase (AC) was immobilized and stabilized on carboxylated polyaniline nanofibers (cPANFs) for the development of antifouling nanobiocatalysts with high enzyme loading and stability. AC was immobilized via three different approaches: covalent attachment (CA), enzyme coating (EC), and magnetically separable enzyme precipitate coating (Mag-EPC). The enzyme activity per unit weight of cPANFs with Mag-EPC was 75 and 300 times higher than that of those with CA and EC, respectively, representing improved enzyme loading in the form of Mag-EPC. After incubation under shaking at 200 rpm for 20 days, Mag-EPC maintained 55% of its initial activity, whereas CA and EC showed 3 and 16% of their initial activities, respectively. The antifouling of highly loaded and stable Mag-EPC against the biofouling/biofilm formation of Pseudomonas aeruginosa was tested under static- and continuous-flow conditions. Biofilm formation in the presence of 40 μg/mL Mag-EPC under static condition was 5 times lower than that under control condition with no addition of Mag-EPC. Under continuous membrane filtration, Mag-EPC delayed the increase of transmembrane pressure (TMP) more effectively as the concentration of added Mag-EPC increased. When separating Mag-EPC and membranes in two different vessels under internal circulation of the culture solution, Mag-EPC maintained a higher permeability than the control with no Mag-EPC addition. It was also confirmed that the addition of Mag-EPC reduced the generation of N-acyl homoserine lactone (AHL) autoinducers. This result reveals that the inhibition of biofilm formation and biofouling in the presence of Mag-EPC is due to the hydrolysis of AHL autoinducers, catalyzed by the immobilized and stabilized AC in the form of Mag-EPC. Mag-EPC of AC with high enzyme loadings and improved stability has demonstrated its great potential as an antifouling agent by reducing biofilm formation and membrane biofouling based on "enzymatic quorum quenching" of autoinducers.

Do Membranes Dream of Electric Tubes? Advanced Membranes Using Carbon Nanotube - Polymer Nanocomposites

NASA Astrophysics Data System (ADS)

de Lannoy, Charles-Francois Pedro Claude Karolek Ghislain

Membrane technologies represent an energy efficient, effective solution for treating municipal and commercial waters/wastewaters. Membranes are predominantly polymer-based and despite steady advances in polymeric materials, they continue to suffer from operational problems including biofouling and breakages. This work addresses these two disparate problems by developing novel CNT-polymer nanocomposite materials that contain variously functionalized carbon nanotubes (fCNTs) in low quantities (<0.5wt%). Several strategies have been employed to achieve highly functional CNT-polymer nanocomposite membranes including blend mixing, ionic charge association, and covalent cross-linking with monomer and oligomer constituents. These CNT-polymer nanocomposite membranes were compared to traditional polymer membranes across various properties including increased Young's Modulus, changes in surface hydrophilicity, fine control over molecular weight cut-off and flux, and surface electrical conductivity. Membranes with high surface electrical conductivity were further tested for their anti-biofouling properties. Finally, CNT stability and polymer compatibility were evaluated throughout membrane manufacture, use, and cleaning. The incorporation of CNTs mixed in bulk phase and linked through ionic associations in polymer matrices showed significant (50%) increases in Young's modulus for certain CNT functionalizations and derivatization percent. Membranes formed with high surface electrical conductivity demonstrated almost complete resistance to biofouling (> 95%) in long-term bacterially challenged experiments. CNTs and polymer mixtures that lacked covalent or ionic bonds were susceptible to significant (up to 10%) loss of CNTs during membrane non-solvent gelation and aggressive chemical cleaning treatment. Functionalized carbon nanotubes endow polymer membranes with their unique strength and electrically conductive properties. These added properties were demonstrated to greatly improve membrane operational efficiency and membrane longevity. CNT-polymer nanocomposite membranes offer low-energy, high-efficiency, and long-lifetime alternatives to traditional polymer membranes. With further advances in polymeric nanomaterials, membrane technology has the potential for wide applicability across many fields outside of water filtration and desalination.

Field results of antifouling techniques for optical instruments

USGS Publications Warehouse

Strahle, W.J.; Hotchkiss, F.S.; Martini, Marinna A.

1998-01-01

An anti-fouling technique is developed for the protection of optical instruments from biofouling which leaches a bromide compound into a sample chamber and pumps new water into the chamber prior to measurement. The primary advantage of using bromide is that it is less toxic than the metal-based antifoulants. The drawback of the bromide technique is also discussed.

Genetic diversity in two introduced biofouling amphipods (Amphipods valida and Jassa marmorata) along the Pacific North American coast: investigation into molecular identification and cryptic diversity

EPA Science Inventory

We investigated patterns of genetic diversity among invasive populations of A. valida and J. marmorata from the Pacific North American coast to assess the accuracy of morphological identification and determine whether or not cryptic diversity and multiple introductions contribute...

Airfoil-shaped micro-mixers for reducing fouling on membrane surfaces

DOEpatents

Ho, Clifford K; Altman, Susan J; Clem, Paul G; Hibbs, Michael; Cook, Adam W

2012-10-23

An array of airfoil-shaped micro-mixers that enhances fluid mixing within permeable membrane channels, such as used in reverse-osmosis filtration units, while minimizing additional pressure drop. The enhanced mixing reduces fouling of the membrane surfaces. The airfoil-shaped micro-mixer can also be coated with or comprised of biofouling-resistant (biocidal/germicidal) ingredients.

Bioaugmentation for Groundwater Remediation

DTIC Science & Technology

2010-02-01

in biofouling control. Citric acid is optimal as it serves as an acid and a metal chelating agent • Daily application of chlorine dioxide or other...26 6.6.4.1 Chlorinated Ethenes and Ethene ............................................. 26 6.6.4.2 Volatile Fatty Acids ...47 8.3.2 Passive Bioaugmentation and Passive Biostimulation Comparison ......... 48 8.3.2.1 Site Description

Ocean Thermal Energy Conversion power system development. Phase I. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1978-12-04

This report covers the conceptual and preliminary design of closed-cycle, ammonia, ocean thermal energy conversion power plants by Westinghouse Electric Corporation. Preliminary designs for evaporator and condenser test articles (0.13 MWe size) and a 10 MWe modular experiment power system are described. Conceptual designs for 50 MWe power systems, and 100 MWe power plants are also descirbed. Design and cost algorithms were developed, and an optimized power system design at the 50 MWe size was completed. This design was modeled very closely in the test articles and in the 10 MWe Modular Application. Major component and auxiliary system design, materials,more » biofouling, control response, availability, safety and cost aspects are developed with the greatest emphasis on the 10 MWe Modular Application Power System. It is concluded that all power plant subsystems are state-of-practice and require design verification only, rather than continued research. A complete test program, which verifies the mechanical reliability as well as thermal performance, is recommended and described.« less

A Wave Glider for Studies of Biofouling and Ocean Productivity

DTIC Science & Technology

2017-11-07

sensors for conductivity, water and air temperature , dissolved oxygen , chlorophyll-a fluorescence, wind speed and direction, barometric pressure, and...endurance, reduce fuel consumption , and reduce carbon emissions. During deployments, vessels encounter a range of planktonic assemblages and ocean...with an acoustic Doppler current profiler, an optical camera system, and standard sensors for conductivity, water and air temperature , dissolved

Development of a self-cleaning sensor membrane for implantable biosensors.

PubMed

Gant, Rebecca M; Hou, Yaping; Grunlan, Melissa A; Coté, Gerard L

2009-09-01

Fibrous tissue encapsulation may slow the diffusion of the target analyte to an implanted sensor and compromise the optical signal. Poly(N-isopropylacrylamide) (PNIPAAm) hydrogels are thermoresponsive, exhibiting temperature-modulated swelling behavior that could be used to prevent biofouling. Unfortunately, PNIPAAm hydrogels are limited by poor mechanical strength. In this study, a unique thermoresponsive nanocomposite hydrogel was developed to create a mechanically robust self-cleaning sensor membrane for implantable biosensors. This hydrogel was prepared by the photochemical cure of an aqueous solution of NIPAAm and copoly(dimethylsiloxane/methylvinylsiloxane) colloidal nanoparticles ( approximately 219 nm). At temperatures above the volume phase transition temperature (VPTT) of approximately 33-34 degrees C, the hydrogel deswells and becomes hydrophobic, whereas lowering the temperature below the VPTT causes the hydrogel to swell and become hydrophilic. The potential of this material to minimize biofouling via temperature-modulation while maintaining sensor viability was investigated using glucose as a target analyte. PNIPAAm composite hydrogels with and without poration were compared to a pure PNIPAAm hydrogel and a nonthermoresponsive poly(ethylene glycol) (PEG) hydrogel. Poration led to a substantial increase in diffusion. Cycling the temperature of the nanocomposite hydrogels around the VPTT caused significant detachment of GFP-H2B 3T3 fibroblast cells.

The anti-biofouling behavior of high voltage pulse electric field (HPEF) mediated by carbon fiber composite coating in seawater.

PubMed

Feng, Tiantian; Wu, Jinyi; Chai, Ke; Yang, Pengpeng

2018-04-25

One of the most important research areas in the marine industry is to investigate new and effective anti-biofouling technologies. In this study, high voltage pulse electric field (HPEF) mediated by carbon fiber (CF) composite coating was utilized to prevent the fouling of bacteria, microalgae and barnacle larvae in seawater. The plate count, 2, 3, 5-triphenyl-tetrazolium chloride (TTC) reduction assay and neutral red (NR) staining and larval motility detection showed that the inactivation rates were at the highest levels, which reached 99.1%, 99.9%, 99.7%, 98.7% and 85% respectively for Pseudomonas sp., Vibrio sp., iron bacteria, Navicula sp. and the second stage nauplii of Balanus reticulatus, under the HPEF with 19 kV pulse amplitude, 23.15 kHz frequency and 0.5 duty cycle. The field-emission scanning electron microscopy (FE-SEM) of Navicula sp. revealed that the HPEF brought about the cell lysis and the cell organic matter release on the coating, which could be the mechanism of the inactivation by the HPEF. Additionally, the FE-SEM and Raman spectroscopy indicated that the HPEF hardly damaged the coating. Copyright © 2018 Elsevier B.V. All rights reserved.

Introduction to the symposium--barnacle biology: essential aspects and contemporary approaches.

PubMed

Zardus, John D

2012-09-01

Barnacles have evolved a number of specialized features peculiar for crustaceans: they produce a calcified, external shell; they exhibit sexual strategies involving dioecy and androdioecy; and some have become internal parasites of other Crustacea. The thoroughly sessile habit of adults also belies the highly mobile and complex nature of their larval stages. Given these and other remarkable innovations in their natural history, it is perhaps not surprising that barnacles present a spectrum of opportunities for study. This symposium integrates research on barnacles in the areas of larval biology, biofouling, reproduction, biogeography, speciation, population genetics, ecological genomics, and phylogenetics. Pioneering comparisons are presented of metamorphosis among barnacles from three major lineages. Biofouling is investigated from the perspectives of biochemical and biomechanical mechanisms. Tradeoffs in reproductive specializations are scrutinized through theoretical modeling and empirical validation. Patterns of endemism and diversity are delineated in Australia and intricate species boundaries in the genus Chthamalus are elucidated for the Indo-Pacific. General methodological concerns with population expansion studies in crustaceans are highlighted using barnacle models. Data from the first, draft barnacle genome are employed to examine location-specific selection. Lastly, barnacle evolution is framed in a deep phylogenetic context and hypothetical origins of defined characters are outlined and tested.

Potential biofouling of spacecraft propellant systems due to contaminated deionized water

NASA Astrophysics Data System (ADS)

Hogue, Patrick

2006-08-01

Deionized (DI) water, with a density close to hydrazine, is used to fill spacecraft propellant tanks for mechanical testing during ground operations, after which is it removed and the tanks dried for use with anhydrous hydrazine. Pure nitrogen is used as a pressurant during storage and during water fill and drain operations. Since DI water systems are notorious for contamination by slime-forming bacteria, DI water intended for use in New Horizons and STEREO hydrazine tanks at APL was assessed for microorganism content using the heterotrophic plate count (HPC) method. Results show that some growth occurred during storage of DI water in propellant tanks, however not at the logarithmic rate associated with well-nourished bacteria. Ralstonia and Burkholderia were present in DI water on-loaded however only Ralstonia was present in off-loaded water. One possible source of nutrients during water storage in propellant tanks is organic material originating from the EPDM (EPR per AF-E-332) expulsion diaphragm. This paper will demonstrate potential for bio-fouling of spacecraft propulsion systems due to growth of slime-forming bacteria and will suggest that specifications controlling microorganism content should be imposed on water used for spacecraft ground testing.

Antifouling aptasensor for the detection of adenosine triphosphate in biological media based on mixed self-assembled aptamer and zwitterionic peptide.

PubMed

Wang, Guixiang; Su, Xiaoli; Xu, Qingjun; Xu, Guiyun; Lin, Jiehua; Luo, Xiliang

2018-03-15

Direct detection of targets in complex biological media with conventional biosensors is an enormous challenge due to the nonspecific adsorption and severe biofouling. In this work, a facile strategy for sensitive and low fouling detection of adenosine triphosphate (ATP) is developed through the construction of a mixed self-assembled biosensing interface, which was composed of zwitterionic peptide (antifouling material) and ATP aptamer (bio-recognition element). The peptide and aptamer (both containing thiol groups) were simultaneously self-assembled onto gold electrode surface electrodeposited with gold nanoparticles. The developed aptasensor possessed high selectivity and sensitivity for ATP, and it showed a wide linear response range towards ATP from 0.1pM to 5nM. Owing to the presence of peptide with excellent antifouling property in the biosensing interface, the aptasensor can detect ATP in complex biological media with remarkably reduced biofouling or nonspecific adsorption effect. Moreover, it can directly detect ATP in 1% human whole blood without suffering from any significant interference, indicating its great potential for practical assaying of ATP in biological samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Opportunistic pathogens and faecal indicators in drinking water associated biofilms in Cluj, Romania.

PubMed

Farkas, A; Drăgan-Bularda, M; Ciatarâş, D; Bocoş, B; Tigan, S

2012-09-01

Biofouling occurs without exception in all water systems, with undesirable effects such as biocorrosion and deterioration of water quality. Drinking water associated biofilms represent a potential risk to human health by harbouring pathogenic or toxin-releasing microorganisms. This is the first study investigating the attached microbiota, with potential threat to human health, in a public water system in Romania. The presence and the seasonal variation of viable faecal indicators and opportunistic pathogens were investigated within naturally developed biofilms in a drinking water treatment plant. Bacterial frequencies were correlated with microbial loads in biofilms as well as with physical and chemical characteristics of biofilms and raw water. The biofilms assessed in the current study proved to be extremely active microbial consortia. High bacterial numbers were recovered by cultivation, including Pseudomonas aeruginosa, Escherichia coli, Aeromonas hydrophila, intestinal enterococci and Clostridium perfringens. There were no Legionella spp. detected in any biofilm sample. Emergence of opportunistic pathogens in biofilms was not significantly affected by the surface material, but by the treatment process. Implementation of a water safety plan encompassing measures to prevent microbial contamination and to control biofouling would be appropriate.

Marketing netcoatings for aquaculture.

PubMed

Martin, Robert J

2014-10-17

Unsustainable harvesting of natural fish stocks is driving an ever growing marine aquaculture industry. Part of the aquaculture support industry is net suppliers who provide producers with nets used in confining fish while they are grown to market size. Biofouling must be addressed in marine environments to ensure maximum product growth by maintaining water flow and waste removal through the nets. Biofouling is managed with copper and organic biocide based net coatings. The aquaculture industry provides a case study for business issues related to entry of improved fouling management technology into the marketplace. Several major hurdles hinder entry of improved novel technologies into the market. The first hurdle is due to the structure of business relationships. Net suppliers can actually cut their business profits dramatically by introducing improved technologies. A second major hurdle is financial costs of registration and demonstration of efficacy and quality product with a new technology. Costs of registration are prohibitive if only the net coatings market is involved. Demonstration of quality product requires collaboration and a team approach between formulators, net suppliers and farmers. An alternative solution is a vertically integrated business model in which the support business and product production business are part of the same company.

Marketing Netcoatings for Aquaculture

PubMed Central

Martin, Robert J.

2014-01-01

Unsustainable harvesting of natural fish stocks is driving an ever growing marine aquaculture industry. Part of the aquaculture support industry is net suppliers who provide producers with nets used in confining fish while they are grown to market size. Biofouling must be addressed in marine environments to ensure maximum product growth by maintaining water flow and waste removal through the nets. Biofouling is managed with copper and organic biocide based net coatings. The aquaculture industry provides a case study for business issues related to entry of improved fouling management technology into the marketplace. Several major hurdles hinder entry of improved novel technologies into the market. The first hurdle is due to the structure of business relationships. Net suppliers can actually cut their business profits dramatically by introducing improved technologies. A second major hurdle is financial costs of registration and demonstration of efficacy and quality product with a new technology. Costs of registration are prohibitive if only the net coatings market is involved. Demonstration of quality product requires collaboration and a team approach between formulators, net suppliers and farmers. An alternative solution is a vertically integrated business model in which the support business and product production business are part of the same company. PMID:25329615

Basement Membrane-Based Glucose Sensor Coatings Enhance Continuous Glucose Monitoring in Vivo.

PubMed

Klueh, Ulrike; Qiao, Yi; Czajkowski, Caroline; Ludzinska, Izabela; Antar, Omar; Kreutzer, Donald L

2015-08-25

Implantable glucose sensors demonstrate a rapid decline in function that is likely due to biofouling of the sensor. Previous efforts directed at overcoming this issue has generally focused on the use of synthetic polymer coatings, with little apparent effect in vivo, clearly a novel approach is required. We believe that the key to extending sensor life span in vivo is the development of biocompatible basement membrane (BM) based bio-hydrogels as coatings for glucose sensors. BM based bio-hydrogel sensor coatings were developed using purified BM preparations (ie, Cultrex from Trevigen Inc). Modified Abbott sensors were coated with Cultrex BM extracts. Sensor performance was evaluated for the impact of these coatings in vitro and in vivo in a continuous glucose monitoring (CGM) mouse model. In vivo sensor function was assessed over a 28-day time period expressed as mean absolute relative difference (MARD) values. Tissue reactivity of both Cultrex coated and uncoated glucose sensors was evaluated at 7, 14, 21 and 28 days post-sensor implantation with standard histological techniques. The data demonstrate that Cultrex-based sensor coatings had no effect on glucose sensor function in vitro. In vivo glucose sensor performance was enhanced following BM coating as determined by MARD analysis, particularly in weeks 2 and 3. In vivo studies also demonstrated that Cultrex coatings significantly decreased sensor-induced tissue reactions at the sensor implantation sites. Basement-membrane-based sensor coatings enhance glucose sensor function in vivo, by minimizing or preventing sensor-induced tissues reactions. © 2015 Diabetes Technology Society.

Use of Treated Municipal Wastewater as Power Plant Cooling System Makeup Water: Tertiary Treatment versus Expanded Chemical Regimen for Recirculating Water Quality Management

DOE Office of Scientific and Technical Information (OSTI.GOV)

David Dzombak; Radisav Vidic; Amy Landis

Treated municipal wastewater is a common, widely available alternative source of cooling water for thermoelectric power plants across the U.S. However, the biodegradable organic matter, ammonia-nitrogen, carbonate and phosphates in the treated wastewater pose challenges with respect to enhanced biofouling, corrosion, and scaling, respectively. The overall objective of this study was to evaluate the benefits and life cycle costs of implementing tertiary treatment of secondary treated municipal wastewater prior to use in recirculating cooling systems. The study comprised bench- and pilot-scale experimental studies with three different tertiary treated municipal wastewaters, and life cycle costing and environmental analyses of various tertiarymore » treatment schemes. Sustainability factors and metrics for reuse of treated wastewater in power plant cooling systems were also evaluated. The three tertiary treated wastewaters studied were: secondary treated municipal wastewater subjected to acid addition for pH control (MWW_pH); secondary treated municipal wastewater subjected to nitrification and sand filtration (MWW_NF); and secondary treated municipal wastewater subjected nitrification, sand filtration, and GAC adsorption (MWW_NFG). Tertiary treatment was determined to be essential to achieve appropriate corrosion, scaling, and biofouling control for use of secondary treated municipal wastewater in power plant cooling systems. The ability to control scaling, in particular, was found to be significantly enhanced with tertiary treated wastewater compared to secondary treated wastewater. MWW_pH treated water (adjustment to pH 7.8) was effective in reducing scale formation, but increased corrosion and the amount of biocide required to achieve appropriate biofouling control. Corrosion could be adequately controlled with tolytriazole addition (4-5 ppm TTA), however, which was the case for all of the tertiary treated waters. For MWW_NF treated water, the removal of ammonia by nitrification helped to reduce the corrosivity and biocide demand. Also, the lower pH and alkalinity resulting from nitrification reduced the scaling to an acceptable level, without the addition of anti-scalant chemicals. Additional GAC adsorption treatment, MWW_NFG, yielded no net benefit. Removal of organic matter resulted in pitting corrosion in copper and cupronickel alloys. Negligible improvement was observed in scaling control and biofouling control. For all of the tertiary treatments, biofouling control was achievable, and most effectively with pre-formed monochloramine (2-3 ppm) in comparison with NaOCl and ClO2. Life cycle cost (LCC) analyses were performed for the tertiary treatment systems studied experimentally and for several other treatment options. A public domain conceptual costing tool (LC3 model) was developed for this purpose. MWW_SF (lime softening and sand filtration) and MWW_NF were the most cost-effective treatment options among the tertiary treatment alternatives considered because of the higher effluent quality with moderate infrastructure costs and the relatively low doses of conditioning chemicals required. Life cycle inventory (LCI) analysis along with integration of external costs of emissions with direct costs was performed to evaluate relative emissions to the environment and external costs associated with construction and operation of tertiary treatment alternatives. Integrated LCI and LCC analysis indicated that three-tiered treatment alternatives such as MWW_NSF and MWW_NFG, with regular chemical addition for treatment and conditioning and/or regeneration, tend to increase the impact costs and in turn the overall costs of tertiary treatment. River water supply and MWW_F alternatives with a single step of tertiary treatment were associated with lower impact costs, but the contribution of impact costs to overall annual costs was higher than all other treatment alternatives. MWW_NF and MWW_SF alternatives exhibited moderate external impact costs with moderate infrastructure and chemical conditioner dosing, which makes them (especially MWW_NF) better treatment alternatives from the environmental sustainability perspective since they exhibited minimal contribution to environmental damage from emissions.« less

Nanocomposite strategies for limiting medical and marine biofouling

NASA Astrophysics Data System (ADS)

Cooper, Scott Patrick

Microorganisms affect many aspects of human life. When microorganisms colonize a surface, the resulting microbial community is called a biofilm. Biofilms can negatively affect human health and productivity. Osteomyelitis is caused by biofilms of bacteria attached to the bone. These biofilms pose a threat to human life and lead to the loss of healthy tissue. Biofilms attached to marine vessels decrease the fuel economy of ships, resulting in a significant economic cost. There is a need to develop new materials which eradicate and prevent biofouling. Nanocomposites and mixed-phase organic/inorganic materials are presented in various embodiments as a means to limit biofouling. Antibiotic-filled microspheres are created to improve the treatment of osteomyelitis. These microspheres consist of bioactive glass and poly(n-vinylpyrrolidone) (PVP) or gelatin. Bioactive glasses have historically been shown to promote the regeneration of bone. Sol-gel chemistry is used to make the bioactive glass component, in this case a calcium silicate. The low temperature of the reaction allows organic molecules such as drugs and polymers to be blended with the glass. The catalyst used during the sol-gel reaction affects the structure and composition of the microspheres. Base catalysis leads to microspheres that exhibit behavior indicative of a nanocomposite structure. Acid catalysis produces microspheres that appear to exist as more as a mixed phase between silica and PVP. These structures directly affect the stability of the microspheres in simulated body fluid (SBF): base-catalyzed microspheres degrade within the first day in SBF, while acid-catalyzed microspheres are stable for at least one week. The morphology of acid-catalyzed microspheres is directly affected by the following compositional parameters: molecular weight of PVP, concentration of PVP, and concentration of calcium. Solid, hollow, and core/shell morphologies are produced by adjusting these parameters. These morphologies are likely caused by various rates of silicate hydrolysis, condensation, and hydrogen bonding to PVP. Viscosity of the sol plays little role in determining the diameter of the dried microspheres. An antibiotic, vancomycin, is successfully incorporated into these hybrid microspheres. Vancomycin is released for 5-7 days as measured by UV absorption. An in vitro assay against cultures of Staphylococcus aureus demonstrates that the drug remains effective for 4 days. Marine biofouling is addressed by imparting topography onto silica-reinforced poly(dimethylsiloxane) elastomeric (PDMSe) films. Swimming zoospores from the green alga Ulva are used as a model fouling organism. A bio-inspired topography deterred attachment of the zoospores by 70-80% over a 4-hr assay. Image analysis of the zoospores suggests that the topography may inhibit biofilm formation by disrupting the early-stage aggregation of spores on the surface. The attachment kinetics fit, with high correlation, equations used to describe that adsorption of bacteria to surfaces. This suggests the same physical phenomena drives the attachment of bacteria and swimming algal zoospores to solid surfaces.

Antifouling processes and toxicity effects of antifouling paints on marine environment. A review.

PubMed

Amara, Intissar; Miled, Wafa; Slama, Rihab Ben; Ladhari, Neji

2018-01-01

The production infrastructure in aquaculture invariably is a complex assortment of submerged components with cages, nets, floats and ropes. Cages are generally made from polyamide or high density polyethylene (PEHD). All of these structures serve as surfaces for biofouling. However, cage nets and supporting infrastructure offer fouling organisms thousands of square meters of multifilament netting. That's why, before immersing them in seawater, they should be coated with an antifouling agent. It helps to prevent net occlusion and to increase its lifespan. Biofouling in marine aquaculture is a specific problem and has three main negative effects. It causes net occlusion and so restricts water and oxygen exchange. Besides, the low dissolved oxygen levels from poor water exchange increases the stress levels of fish, lowers immunity and increases vulnerability to disease. Also, the extra weight imposed by fouling causes cage deformation and structural fatigue. The maintenance and loss of equipment cause the increase of production costs for the industry. Biocides are chemical substances that can prohibit or kill microorganisms responsible for biofouling. The expansion of the aquaculture industry requires the use of more drugs, disinfectants and antifoulant compounds (biocides) to eliminate the microorganisms in the aquaculture facilities. Unfortunately, the use of biocides in the aquatic environment has proved to be harmful as it has toxic effects on the marine environment. The most commonly used biocides in antifouling paints are Tributyltin (TBT), Chlorothalonil, Dichlofluanid, Sea-Nine 211, Diuron, Irgarol 1051 and Zinc Pyrithione. Restrictions were imposed on the use of TBT, that's why organic booster biocides were recently introduced. The replacement products are generally based on copper metal oxides and organic biocides. This paper provides an overview of the effects of antifouling biocides on aquatic organisms. It will focus on the eight booster biocides in common use, despite little data are available for some of them. Toxicity values and effects of these antifoulants will also be mentioned for different species of fish, crustaceans, invertebrates and algae. Copyright © 2017 Elsevier B.V. All rights reserved.

Self-Cleaning Coatings and Materials for Decontaminating Field-Deployable Land and Water-Based Optical Systems

NASA Technical Reports Server (NTRS)

Ryan, Robert; Underwood, Lauren; Holekamp, Kara; May, George; Spiering, Bruce; Davis, Bruce

2011-01-01

This technology exploits the organic decomposition capability and hydrophilic properties of the photocatalytic material titanium dioxide (TiO2), a nontoxic and non-hazardous substance, to address contamination and biofouling issues in field-deployed optical sensor systems. Specifically, this technology incorporates TiO2 coatings and materials applied to, or integrated as a part of, the optical surfaces of sensors and calibration sources, including lenses, windows, and mirrors that are used in remote, unattended, ground-based (land or maritime) optical sensor systems. Current methods used to address contamination or biofouling of these optical surfaces in deployed systems are costly, toxic, labor intensive, and non-preventative. By implementing this novel technology, many of these negative aspects can be reduced. The functionality of this innovative self-cleaning solution to address the problem of contamination or biofouling depends on the availability of a sufficient light source with the appropriate spectral properties, which can be attained naturally via sunlight or supplemented using artificial illumination such as UV LEDs (light emitting diodes). In land-based or above-water systems, the TiO2 optical surface is exposed to sunlight, which catalyzes the photocatalytic reaction, facilitating both the decomposition of inorganic and organic compounds, and the activation of superhydrophilic properties. Since underwater optical surfaces are submerged and have limited sunlight exposure, supplementary UV light sources would be required to activate the TiO2 on these optical surfaces. Nighttime operation of land-based or above-water systems would require this addition as well. For most superhydrophilic self-cleaning purposes, a rainwater wash will suffice; however, for some applications an attached rainwater collector/ dispenser or other fresh water dispensing system may be required to wash the optical surface and initiate the removal of contaminates. Deployment of this non-toxic,non-hazardous-technology will take advantage of environmental elements (i.e. rain and sunlight), increase the longevity of unattended optical systems, increase the amount of time between required maintenance, and improve the long-term accuracy of sensor measurements.

Metabolic Biofouling of Glucose Sensors in Vivo: Role of Tissue Microhemorrhages

PubMed Central

Klueh, Ulrike; Liu, Zenghe; Feldman, Ben; Henning, Timothy P; Cho, Brian; Ouyang, Tianmei; Kreutzer, Don

2011-01-01

Objective: Based on our in vitro study that demonstrated the adverse effects of blood clots on glucose sensor function, we hypothesized that in vivo local tissue hemorrhages, induced as a consequence of sensor implantation or sensor movement post-implantation, are responsible for unreliable readings or an unexplained loss of functionality shortly after implantation. Research Design and Methods: To investigate this issue, we utilized real-time continuous monitoring of blood glucose levels in a mouse model. Direct injection of blood at the tissue site of sensor implantation was utilized to mimic sensor-induced local tissue hemorrhages. Results: It was found that blood injections, proximal to the sensor, consistently caused lowered sensor glucose readings, designated temporary signal reduction, in vivo in our mouse model, while injections of plasma or saline did not have this effect. Conclusion: These results support our hypothesis that tissue hemorrhage and resulting blood clots near the sensor can result in lowered local blood glucose concentrations due to metabolism of glucose by the clot. The lowered local blood glucose concentration led to low glucose readings from the still functioning sensor that did not reflect the systemic glucose level. PMID:21722574

In vivo Electrochemical Biosensor for Brain Glutamate Detection: A Mini Review

PubMed Central

HAMDAN, Siti Kartika; MOHD ZAIN, ainiharyati

2014-01-01

Glutamate is one of the most prominent neurotransmitters in mammalian brains, which plays an important role in neuronal excitation. High levels of neurotransmitter cause numerous alterations, such as calcium overload and the dysfunction of mitochondrial and oxidative stress. These alterations may lead to excitotoxicity and may trigger multiple neuronal diseases, such as Alzheimer’s disease, stroke, and epilepsy. Excitotoxicity is a pathological process that damages nerve cells and kills cells via excessive stimulation by neurotransmitters. Monitoring the concentration level of brain glutamate via an implantable microbiosensor is a promising alternative approach to closely investigate in the function of glutamate as a neurotransmitter. This review outlines glutamate microbiosensor designs to enhance the sensitivity of glutamate detection with less biofouling occurrence and minimal detection of interference species. There are many challenges in the development of a reproducible and stable implantable microbiosensor because many factors and limitations may affect the detection performance. However, the incorporation of multiple scales is needed to address the basic issues and combinations across the various disciplines needed to achieve the success of the system to overcome the challenges in the development of an implantable glutamate biosensor. PMID:25941459

[Design and experimentation of marine optical buoy].

PubMed

Yang, Yue-Zhong; Sun, Zhao-Hua; Cao, Wen-Xi; Li, Cai; Zhao, Jun; Zhou, Wen; Lu, Gui-Xin; Ke, Tian-Cun; Guo, Chao-Ying

2009-02-01

Marine optical buoy is of important value in terms of calibration and validation of ocean color remote sensing, scientific observation, coastal environment monitoring, etc. A marine optical buoy system was designed which consists of a main and a slave buoy. The system can measure the distribution of irradiance and radiance over the sea surface, in the layer near sea surface and in the euphotic zone synchronously, during which some other parameters are also acquired such as spectral absorption and scattering coefficients of the water column, the velocity and direction of the wind, and so on. The buoy was positioned by GPS. The low-power integrated PC104 computer was used as the control core to collect data automatically. The data and commands were real-timely transmitted by CDMA/GPRS wireless networks or by the maritime satellite. The coastal marine experimentation demonstrated that the buoy has small pitch and roll rates in high sea state conditions and thus can meet the needs of underwater radiometric measurements, the data collection and remote transmission are reliable, and the auto-operated anti-biofouling devices can ensure that the optical sensors work effectively for a period of several months.

PEGylated Polyaniline Nanofibers: Antifouling and Conducting Biomaterial for Electrochemical DNA Sensing.

PubMed

Hui, Ni; Sun, Xiaotian; Niu, Shuyan; Luo, Xiliang

2017-01-25

Biofouling arising from nonspecific adsorption is a substantial outstanding challenge in diagnostics and disease monitoring, and antifouling sensing interfaces capable of reducing the nonspecific adsorption of proteins from biological complex samples are highly desirable. We present herein the preparation of novel composite nanofibers through the grafting of polyethylene glycol (PEG) polymer onto polyaniline (PANI) nanofibers and their application in the development of antifouling electrochemical biosensors. The PEGylated PANI (PANI/PEG) nanofibers possessed large surface area and remained conductive and at the same time demonstrated excellent antifouling performances in single protein solutions as well as complex human serum samples. Sensitive and low fouling electrochemical biosensors for the breast cancer susceptibility gene (BRCA1) can be easily fabricated through the attachment of DNA probes to the PANI/PEG nanofibers. The biosensor showed a very high sensitivity to target BRCA1 with a linear range from 0.01 pM to 1 nM and was also efficient enough to detect DNA mismatches with satisfactory selectivity. Moreover, the DNA biosensor based on the PEGylated PANI nanofibers supported the quantification of BRCA1 in complex human serum, indicating great potential of this novel biomaterial for application in biosensors and bioelectronics.

Nanostructured Block Copolymer Coatings for Biofouling Inhibition

DTIC Science & Technology

2015-06-30

nm) High resolution vibrational sensitive images Figure 7 - The instrument provides best-in-world performance. The images are of a boron nitride...2 patents pending, publications and some trade secrets. The pure biocide has been tested by independent labs for toxicity to various mammals and...cash investments in Sylleta, which continue. In Figure 8 are the data on the toxicity of the active ingredient (biocide), which is surface tethered in

Draft Genome Sequences of Four Alteromonas macleodii Strains Isolated from Copper Coupons and Grown Long-Term at Elevated Copper Levels.

PubMed

Cusick, Kathleen D; Dale, Jason R; Little, Brenda J; Biffinger, Justin C

2016-11-23

Alteromonas macleodii is a marine bacterium involved in the early stages of biofouling on ship hulls treated with copper as an antifouling agent. We report here the draft genome sequences of an A. macleodii strain isolated from copper coupons and three laboratory mutants grown long-term at elevated copper levels. Copyright © 2016 Cusick et al.

Characterization of Biofouling Marine Caulobacters and Their Adhesive Holdfast

DTIC Science & Technology

1988-06-30

SAD-A 197 211 _, 111 3 CEILL GJU JREPORT DOCUMENTATION PAGE la. REPORT SECURITY CLASSIFiCATION ’b RESTRICTIVE MARKIN6, S U 1 2a. SECURITY...what types of surfaces to which the Caulobacters will attach. This was approached by the preparation of glass surfaces covalently modified with a...finding that dimethyldichlorosilane treated glass (ie classical "silanizing") was reasonably effective in discouraging attachment, a convenience for many

Variation in Adhesion Strength of Balanus Eburneus, Crassostrea Virginica and Hydroides Dianthus to Fouling-Release Coatings

DTIC Science & Technology

2001-03-01

www.informaworld.com/smpp/title~content=t713454511 Variation in adhesion strength of Balanus eburneus, crassostrea virginica and hydroides dianthus to...in adhesion strength of Balanus eburneus, crassostrea virginica and hydroides dianthus to fouling-release coatings’, Biofouling, 17: 2, 155 — 167...4. TITLE AND SUBTITLE Variation in adhesion strength of Balanus eburneus, crassostrea virginica and hydroides dianthus to fouling-release coatings

Variation in Adhesion Strength of Balanus eburneus, Crassostrea virginica and Hydroides dianthus to Fouling-release Coatings

DTIC Science & Technology

2001-07-01

www.informaworld.com/smpp/title~content=t713454511 Variation in adhesion strength of Balanus eburneus, crassostrea virginica and hydroides dianthus to...in adhesion strength of Balanus eburneus, crassostrea virginica and hydroides dianthus to fouling-release coatings’, Biofouling, 17: 2, 155 — 167...4. TITLE AND SUBTITLE Variation in adhesion strength of Balanus eburneus, crassostrea virginica and hydroides dianthus to fouling-release coatings

Survey of Biofouling an Australian Navy Ships: Crustacea; Isopoda and Amphipoda; Caprellidea

DTIC Science & Technology

2008-01-01

On uptake, ballast water can contain a diversity of plankton and nekton that, depending on the length and temperature of the voyage, may survive...and Sphaeroma walkeri, both previously reported as introduced species and now having a wide distribution , both in Australia and world wide. Other...established as introduced species with a cosmopolitan distribution , both in Australia and worldwide. Other species that were recorded in the survey

Assessing the use of Low Voltage UV-light Emitting Miniature LEDs for Marine Biofouling Control

DTIC Science & Technology

2016-07-01

Piola, 1Bart Salters, Clare Grandison, Mark Ciacic and 1Roelant Hietbrink Maritime Division Defence Science and Technology Group 1Philips...uniformly all over the coating layer. In this report, we present a description of the technology and experimental setup, as well as the results of...UNCLASSIFIED Published by Maritime Division Defence Science and Technology Group 506 Lorimer St Fishermans Bend, Victoria 3207 Australia

Electrodepositable alginate membranes for enzymatic sensors: An amperometric glucose biosensor for whole blood analysis.

PubMed

Márquez, A; Jiménez-Jorquera, C; Domínguez, C; Muñoz-Berbel, X

2017-11-15

Simple and disposable point of care systems are usually the best solution for chronic patients to get a rapid diagnosis in home care context. However, their main drawback relies on the poor reliability derived from the low stability of the bio-recognition elements and low quality of the transducers. In the current work, we study the use of electrodeposited calcium alginate hydrogels as a biocompatible matrix in the development of enzymatic amperometric biosensors for whole blood analysis, to enhance the enzymes stability and to protect the transducer from biofouling. The alginate electrodeposition involves the controlled Ca 2+ release, so the gel thickness can be modulated. In the biosensor, horseradish peroxidase (HRP) and glucose oxidase (GOD) were electrodeposited within the hydrogel and the activity of the bi-enzymatic system was analyzed chronoamperometrically using 3,3',5,5'-Tetramethylbenzidine (TMB) as the mediator. Besides enzyme entrapment, the obtained gels protected the transducer from biofouling, enabling the reuse of the transducer after hydrogel removal and re-electrodeposition. The biosensors showed good analytical characteristics to glucose determination in whole blood samples, discriminating among healthy and hyperglycemic samples, with good sensitivity (- 0.27µAcm -2 mM -1 ), low limit of detection (126µM) and long lineal range (2-12mM). Copyright © 2017. Published by Elsevier B.V.

Designing a biocidal reverse osmosis membrane coating: Synthesis and biofouling properties

DOE PAGES

Hibbs, Michael R.; McGrath, Lucas K.; Kang, Seoktae; ...

2015-12-04

In this study, a biocidal coating was developed in order to reduce biofouling on a reverse osmosis (RO) membrane using a quaternary ammonium (QA) functionalized polymer. The synthesis of a series of polysulfone (PS) ionomers with QA groups is described, and a method for spraying these QA ionomers as an alcoholic solution, which dried into water insoluble coatings. Contact angle and streaming potential were used to analyze the coating's hydrophilicity and surface charge. Both PS-QA1 and the commercial RO membrane had an apparent contact angle of 68° that increased to 126° for PS-QA12 corresponding to alkyl chain length. A negativelymore » charged particle-probe was used to measure coated and uncoated RO membrane interaction forces. Measured interaction forces correlated strongly with the length of alkyl chains or hydrophobicity of the coated surfaces. Uncoated RO membranes and ones coated with PS-QA were exposed to suspensions of Escherichia coli cells. All four PS-QA coatings showed significant biotoxicity and killed 100% of the E. coli cells, but uncoated RO membranes had metabolically active biofilms. However, coatings tested in a RO crossflow system showed a flux reduction that is attributed to mass transfer resistance due to excessively thick films.« less

Incorporating zosteric acid into silicone coatings to achieve its slow release while reducing fresh water bacterial attachment.

PubMed

Barrios, Carlos A; Xu, Qingwei; Cutright, Teresa; Newby, Bi-min Zhang

2005-03-25

Biofouling has posed serious problems in maritime industry including increased fuel consumptions, economic loss from ship-hull maintenances, contamination of drinking water, and serious corrosion for mechanical instruments. Minimizing the attachment of bacteria and formation of biofilm could be advantageous in reducing the early stages of biofouling. Zosteric acid, a natural product present in eelgrass, was found to have ability for preventing the attachment of some bacteria and barnacles. In this study, the antifouling ability of zosteric acid during the early stages of fouling was evaluated using attachment studies of fresh water bacteria. Simultaneously, various methods were sought for incorporating zosteric acid into silicone to prolong the release of the compound. The main results from this study were that zosteric acid exhibited anti-bacterial attachment regardless of whether it dispersed in water or incorporated into a coating. In addition, the release rate of zosteric acid from the incorporated coatings, particularly those where zosteric acid was uniformly dispersed with aggregates size of 4 microm or less, was orders of magnitude slower than those of previous reports. The release results indicate that the service life of our coatings could be far extended even with a small amount of zosteric acid incorporated.

Designing a biocidal reverse osmosis membrane coating: Synthesis and biofouling properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hibbs, Michael R.; McGrath, Lucas K.; Kang, Seoktae

In this study, a biocidal coating was developed in order to reduce biofouling on a reverse osmosis (RO) membrane using a quaternary ammonium (QA) functionalized polymer. The synthesis of a series of polysulfone (PS) ionomers with QA groups is described, and a method for spraying these QA ionomers as an alcoholic solution, which dried into water insoluble coatings. Contact angle and streaming potential were used to analyze the coating's hydrophilicity and surface charge. Both PS-QA1 and the commercial RO membrane had an apparent contact angle of 68° that increased to 126° for PS-QA12 corresponding to alkyl chain length. A negativelymore » charged particle-probe was used to measure coated and uncoated RO membrane interaction forces. Measured interaction forces correlated strongly with the length of alkyl chains or hydrophobicity of the coated surfaces. Uncoated RO membranes and ones coated with PS-QA were exposed to suspensions of Escherichia coli cells. All four PS-QA coatings showed significant biotoxicity and killed 100% of the E. coli cells, but uncoated RO membranes had metabolically active biofilms. However, coatings tested in a RO crossflow system showed a flux reduction that is attributed to mass transfer resistance due to excessively thick films.« less

Exploring the Role of Coliform Bacteria in Class 1 Integron Carriage and Biofilm Formation During Drinking Water Treatment.

PubMed

Farkas, Anca; Crăciunaş, Cornelia; Chiriac, Cecilia; Szekeres, Edina; Coman, Cristian; Butiuc-Keul, Anca

2016-11-01

This study investigates the role of coliforms in the carriage of class 1 integron and biocide resistance genes in a drinking water treatment plant and explores the relationship between the carriage of such genes and the biofouling abilities of the strain. The high incidence of class 1 integron and biocide resistance genes (33.3 % of the isolates) highlights the inherent risk of genetic contamination posed by coliform populations during drinking water treatment. The association between the presence of intI1 gene and qac gene cassettes, especially qacH, was greater in biofilm cells. In coliforms recovered from biofilms, a higher frequency of class 1 integron elements and higher diversity of genetic patterns occurred, compared to planktonic cells. The coliform isolates under the study proved to mostly carry non-classical class 1 integrons lacking the typical qacEΔ1/sul1 genes or a complete tni module, but bearing the qacH gene. No link was found between the carriage of integron genes and the biofouling degree of the strain, neither in aerobic or in anaerobic conditions. Coliform bacteria isolated from established biofilms rather adhere in oxygen depleted environments, while the colonization ability of planktonic cells is not significantly affected by oxygen availability.

The Impact of Blade Roughness and Biofouling on the Performance of a Horizontal Axis Marine Current Turbine

NASA Astrophysics Data System (ADS)

Flack, Karen; Walker, Jessica; Schultz, Michael; Lust, Ethan

2013-11-01

The impact of blade roughness and biofouling on the performance of a two-bladed horizontal axis marine current turbine was investigated experimentally and numerically. A 0.8 m diameter rotor (1/25th scale) with a NACA 63-618 cross section was tested in a towing tank. The torque, thrust and rotational speed were measured in the range 5 < λ <11 (λ = tip speed ratio). Three different cases were tested: clean blades, artificially fouled blades and roughened blades. The performance of the turbine was predicted using Blade Element Momentum theory and validated using the experimental results. The lift and drag curves necessary for the numerical model were obtained by testing a 2D NACA 63-618 airfoil in a wind tunnel under clean and roughened conditions. The numerical model predicts the trends that were observed in the experimental data for roughened blades. The artificially fouled blades did not adversely affect turbine performance, as the vast majority of the fouling sheared off. For the case of roughened blades, the power coefficient (CP) versus λ curve was significantly offset below that for the clean case. The maximum CP for this condition was 0.34, compared to 0.42 for the clean condition. Work supported by Australian Fulbright Association and ONR.

Design, Fabrication, and In Vitro Testing of an Anti-biofouling Glaucoma Micro-shunt.

PubMed

Harake, Ryan S; Ding, Yuzhe; Brown, J David; Pan, Tingrui

2015-10-01

Glaucoma, one of the leading causes of irreversible blindness, is a progressive neurodegenerative disease. Chronic elevated intraocular pressure (IOP), a prime risk factor for glaucoma, can be treated by aqueous shunts, implantable devices, which reduce IOP in glaucoma patients by providing alternative aqueous outflow pathways. Although initially effective at delaying glaucoma progression, contemporary aqueous shunts often lead to numerous complications and only 50% of implanted devices remain functional after 5 years. In this work, we introduce a novel micro-device which provides an innovative platform for IOP reduction in glaucoma patients. The device design features an array of parallel micro-channels to provide precision aqueous outflow resistance control. Additionally, the device's microfluidic channels are composed of a unique combination of polyethylene glycol materials in order to provide enhanced biocompatibility and resistance to problematic channel clogging from biofouling of aqueous proteins. The microfabrication process employed to produce the devices results in additional advantages such as enhanced device uniformity and increased manufacturing throughput. Surface characterization experimental results show the device's surfaces exhibit significantly less non-specific protein adsorption compared to traditional implant materials. Results of in vitro flow experiments verify the device's ability to provide aqueous resistance control, continuous long-term stability through 10-day protein flow testing, and safety from risk of infection due to bacterial ingression.

Development of the permeability/performance reference compound approach for in situ calibration of semipermeable membrane devices

USGS Publications Warehouse

Huckins, J.N.; Petty, J.D.; Lebo, J.A.; Almeida, F.V.; Booij, K.; Alvarez, D.A.; Cranor, W.L.; Clark, R.C.; Mogensen, B.B.

2002-01-01

Permeability/performance reference compounds (PRCs) are analytically noninterfering organic compounds with moderate to high fugacity from semipermeable membrane devices (SPMDs) that are added to the lipid prior to membrane enclosure. Assuming that isotropic exchange kinetics (IEK) apply and that SPMD-water partition coefficients are known, measurement of PRC dissipation rate constants during SPMD field exposures and laboratory calibration studies permits the calculation of an exposure adjustment factor (EAF). In theory, PRC-derived EAF ratios reflect changes in SPMD sampling rates (relative to laboratory data) due to differences in exposure temperature, membrane biofouling, and flow velocity-turbulence at the membrane surface. Thus, the PRC approach should allow for more accurate estimates of target solute/vapor concentrations in an exposure medium. Under some exposure conditions, the impact of environmental variables on SPMD sampling rates may approach an order of magnitude. The results of this study suggest that most of the effects of temperature, facial velocity-turbulence, and biofouling on the uptake rates of analytes with a wide range of hydrophobicities can be deduced from PRCs with a much narrower range of hydrophobicities. Finally, our findings indicate that the use of PRCs permits prediction of in situ SPMD sampling rates within 2-fold of directly measured values.

Influence of Chlorination and Choice of Materials on Fouling in Cooling Water System under Brackish Seawater Conditions

PubMed Central

Rajala, Pauliina; Bomberg, Malin; Huttunen-Saarivirta, Elina; Priha, Outi; Tausa, Mikko; Carpén, Leena

2016-01-01

Cooling systems remove heat from components and industrial equipment. Water cooling, employing natural waters, is typically used for cooling large industrial facilities, such as power plants, factories or refineries. Due to moderate temperatures, cooling water cycles are susceptible to biofouling, inorganic fouling and scaling, which may reduce heat transfer and enhance corrosion. Hypochlorite treatment or antifouling coatings are used to prevent biological fouling in these systems. In this research, we examine biofouling and materials’ degradation in a brackish seawater environment using a range of test materials, both uncoated and coated. The fouling and corrosion resistance of titanium alloy (Ti-6Al-4V), super austenitic stainless steel (254SMO) and epoxy-coated carbon steel (Intershield Inerta160) were studied in the absence and presence of hypochlorite. Our results demonstrate that biological fouling is intensive in cooling systems using brackish seawater in sub-arctic areas. The microfouling comprised a vast diversity of bacteria, archaea, fungi, algae and protozoa. Chlorination was effective against biological fouling: up to a 10–1000-fold decrease in bacterial and archaeal numbers was detected. Chlorination also changed the diversity of the biofilm-forming community. Nevertheless, our results also suggest that chlorination enhances cracking of the epoxy coating. PMID:28773597

Influence of Chlorination and Choice of Materials on Fouling in Cooling Water System under Brackish Seawater Conditions.

PubMed

Rajala, Pauliina; Bomberg, Malin; Huttunen-Saarivirta, Elina; Priha, Outi; Tausa, Mikko; Carpén, Leena

2016-06-15

Cooling systems remove heat from components and industrial equipment. Water cooling, employing natural waters, is typically used for cooling large industrial facilities, such as power plants, factories or refineries. Due to moderate temperatures, cooling water cycles are susceptible to biofouling, inorganic fouling and scaling, which may reduce heat transfer and enhance corrosion. Hypochlorite treatment or antifouling coatings are used to prevent biological fouling in these systems. In this research, we examine biofouling and materials' degradation in a brackish seawater environment using a range of test materials, both uncoated and coated. The fouling and corrosion resistance of titanium alloy (Ti-6Al-4V), super austenitic stainless steel (254SMO) and epoxy-coated carbon steel (Intershield Inerta160) were studied in the absence and presence of hypochlorite. Our results demonstrate that biological fouling is intensive in cooling systems using brackish seawater in sub-arctic areas. The microfouling comprised a vast diversity of bacteria, archaea, fungi, algae and protozoa. Chlorination was effective against biological fouling: up to a 10-1000-fold decrease in bacterial and archaeal numbers was detected. Chlorination also changed the diversity of the biofilm-forming community. Nevertheless, our results also suggest that chlorination enhances cracking of the epoxy coating.

Archaeal Diversity in Biofilm Technologies Applied to Treat Urban and Industrial Wastewater: Recent Advances and Future Prospects

PubMed Central

Calderón, Kadiya; González-Martínez, Alejandro; Gómez-Silván, Cinta; Osorio, Francisco; Rodelas, Belén; González-López, Jesús

2013-01-01

Biological wastewater treatment (WWT) frequently relies on biofilms for the removal of anthropogenic contaminants. The use of inert carrier materials to support biofilm development is often required, although under certain operating conditions microorganisms yield structures called granules, dense aggregates of self-immobilized cells with the characteristics of biofilms maintained in suspension. Molecular techniques have been successfully applied in recent years to identify the prokaryotic communities inhabiting biofilms in WWT plants. Although methanogenic Archaea are widely acknowledged as key players for the degradation of organic matter in anaerobic bioreactors, other biotechnological functions fulfilled by Archaea are less explored, and research on their significance and potential for WWT is largely needed. In addition, the occurrence of biofilms in WWT plants can sometimes be a source of operational problems. This is the case for membrane bioreactors (MBR), an advanced technology that combines conventional biological treatment with membrane filtration, which is strongly limited by biofouling, defined as the undesirable accumulation of microbial biofilms and other materials on membrane surfaces. The prevalence and spatial distribution of archaeal communities in biofilm-based WWT as well as their role in biofouling are reviewed here, in order to illustrate the significance of this prokaryotic cellular lineage in engineered environments devoted to WWT. PMID:24022691

Architecture, component, and microbiome of biofilm involved in the fouling of membrane bioreactors.

PubMed

Inaba, Tomohiro; Hori, Tomoyuki; Aizawa, Hidenobu; Ogata, Atsushi; Habe, Hiroshi

2017-01-01

Biofilm formation on the filtration membrane and the subsequent clogging of membrane pores (called biofouling) is one of the most persistent problems in membrane bioreactors for wastewater treatment and reclamation. Here, we investigated the structure and microbiome of fouling-related biofilms in the membrane bioreactor using non-destructive confocal reflection microscopy and high-throughput Illumina sequencing of 16S rRNA genes. Direct confocal reflection microscopy indicated that the thin biofilms were formed and maintained regardless of the increasing transmembrane pressure, which is a common indicator of membrane fouling, at low organic-loading rates. Their solid components were primarily extracellular polysaccharides and microbial cells. In contrast, high organic-loading rates resulted in a rapid increase in the transmembrane pressure and the development of the thick biofilms mainly composed of extracellular lipids. High-throughput sequencing revealed that the biofilm microbiomes, including major and minor microorganisms, substantially changed in response to the organic-loading rates and biofilm development. These results demonstrated for the first time that the architectures, chemical components, and microbiomes of the biofilms on fouled membranes were tightly associated with one another and differed considerably depending on the organic-loading conditions in the membrane bioreactor, emphasizing the significance of alternative indicators other than the transmembrane pressure for membrane biofouling.

Basement Membrane-Based Glucose Sensor Coatings Enhance Continuous Glucose Monitoring in Vivo

PubMed Central

Klueh, Ulrike; Qiao, Yi; Czajkowski, Caroline; Ludzinska, Izabela; Antar, Omar; Kreutzer, Donald L.

2015-01-01

Background: Implantable glucose sensors demonstrate a rapid decline in function that is likely due to biofouling of the sensor. Previous efforts directed at overcoming this issue has generally focused on the use of synthetic polymer coatings, with little apparent effect in vivo, clearly a novel approach is required. We believe that the key to extending sensor life span in vivo is the development of biocompatible basement membrane (BM) based bio-hydrogels as coatings for glucose sensors. Method: BM based bio-hydrogel sensor coatings were developed using purified BM preparations (ie, Cultrex from Trevigen Inc). Modified Abbott sensors were coated with Cultrex BM extracts. Sensor performance was evaluated for the impact of these coatings in vitro and in vivo in a continuous glucose monitoring (CGM) mouse model. In vivo sensor function was assessed over a 28-day time period expressed as mean absolute relative difference (MARD) values. Tissue reactivity of both Cultrex coated and uncoated glucose sensors was evaluated at 7, 14, 21 and 28 days post–sensor implantation with standard histological techniques. Results: The data demonstrate that Cultrex-based sensor coatings had no effect on glucose sensor function in vitro. In vivo glucose sensor performance was enhanced following BM coating as determined by MARD analysis, particularly in weeks 2 and 3. In vivo studies also demonstrated that Cultrex coatings significantly decreased sensor-induced tissue reactions at the sensor implantation sites. Conclusion: Basement-membrane-based sensor coatings enhance glucose sensor function in vivo, by minimizing or preventing sensor-induced tissues reactions. PMID:26306494

Evaluation of Pre- and Post- Redevelopment Groundwater Chemical Analyses from LM Monitoring Wells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamp, Susan; Dayvault, Jalena

This report documents the efforts and analyses conducted for the Applied Studies and Technology (AS&T) Ancillary Work Plan (AWP) project titled Evaluation of Pre- and Post- Redevelopment Groundwater Sample Laboratory Analyses from Selected LM Groundwater Monitoring Wells. This effort entailed compiling an inventory of nearly 500 previous well redevelopment events at 16 U.S. Department of Energy Office of Legacy Management (LM) sites, searching the literature for impacts of well redevelopment on groundwater sample quality, and—the focus of this report—evaluating the impacts of well redevelopment on field measurements and sample analytical results. Study Catalyst Monitoring well redevelopment, the surging or high-volumemore » pumping of a well to loosen and remove accumulated sediment and biological build-up from a well, is considered an element of monitoring well maintenance that is implemented periodically during the lifetime of the well to mitigate its gradual deterioration. Well redevelopment has been conducted fairly routinely at a few LM sites in the western United States (e.g., the Grand Junction office site and the Gunnison processing site in Colorado), but at most other sites in this region it is not a routine practice. Also, until recently (2014–2015), there had been no specific criteria for implementing well redevelopment, and documentation of redevelopment events has been inconsistent. A catalyst for this evaluation was the self-identification of these inconsistencies by the Legacy Management Support contractor. As a result, in early 2015 Environmental Monitoring Operations (EMO) staff began collecting and documenting additional field measurements during well redevelopment events. In late 2015, AS&T staff undertook an independent internal evaluation of EMO's well redevelopment records and corresponding pre- and post-well-redevelopment groundwater analytical results. Study Findings Although literature discussions parallel the prevailing industry-wide assumption that well redevelopment is necessary to increase production or to extend the life of a well, no data in the literature indicate that redevelopment affects chemical signatures in monitoring wells. The comprehensive evaluation undertaken for this study also yielded no evidence that redevelopment has any quantifiable or predictable effect on groundwater sample quality. Both short-term and long-term changes in groundwater chemistry were assessed relative to preceding and subsequent well redevelopment events. Although short-term changes in specific conductance or contaminant concentrations likely attributable to well redevelopment were found at some sites, these cases were limited to a small subset of wells in which chemical stratification had been observed. Redevelopment causes mixing of the well water, resulting in short-term impacts, but not in a consistent direction. Long-term groundwater concentration trends of uranium, the primary contaminant of concern at most LM Uranium Mill Tailings Radiation Control Act (UMTRCA) sites, were evaluated for all 16 sites addressed in this study. Based on the data evaluated, there are no apparent impacts of well redevelopment on uranium trends. In most cases where deviations in trends were found, these could be attributed to water level fluctuations or other factors. A few exceptions were found where spikes or marked decreases in uranium concentrations could potentially be related to the preceding well redevelopment, but apparent impacts were neither predictable nor quantifiable. Summary and Recommendations A catalyst for this project was a concern that there was a need for strict criteria for a program-wide approach to well redevelopment at LM sites. There was also an implicit question as to whether well redevelopment was a necessary practice that was being overlooked at some sites. The primary objective of this study was to determine if there are significant differences in laboratory analytical results between pre- and post-redevelopment groundwater samples. Results of this evaluation indicate that this is not the case—groundwater concentrations of uranium, the primary contaminant of concern at most LM UMTRCA sites, generally remained unchanged pre- and post-well-redevelopment. The literature supports redevelopment of monitoring and municipal wells if signs of reduced productivity, biofouling, sediment buildup, or other conditions potentially affecting long-term well integrity are observed. In these cases, use of a downhole camera to examine the condition of the well screen and casing may be useful. However, based on the data sets examined for this study, there is no evidence that well redevelopment is needed in order to obtain samples that have the same chemical concentrations as those in the groundwater. To conclusively demonstrate that point—that is, to define chemical effects—the underlying mechanisms have to be understood. For example, if biofouling is observed in a well and is considered a potential cause of spurious or invalid chemical data, appropriate hypothesis-testing ethodology should be used to test the validity of this claim. Until late 2014, the onset of this project, there was no standard procedure for documenting well redevelopment events; some (perhaps many) had not been captured in the historical record. EMO has made notable progress in this regard since 2015, having established a format for documenting well redevelopment events and associated field measurements, as well as a data repository for capturing those records. This policy should be continued to ensure that all well redevelopment events and associated field observations are recorded and easily tracked.« less

Physiochemical Control of Composition and Location for Fundamental Studies of Biofouling Resistant, High Fouling Release Surfaces

DTIC Science & Technology

2016-06-22

with increased legislation on toxicity requirements, the research community has been actively exploring and developing new, robust, and...with a brominated end functionality. The presence of active radical species only at locations where light interacts with the catalyst affords...i.e., the burying of the reactive bromo chain ends due to the high surface activity of the fluorinated repeat units, which imposes additional steric

Examination of Chemical Adsorption and Marine Biofouling on Metal Surfaces Using Raman Scattering Techniques and Electrochemical Impedance Spectroscopy

DTIC Science & Technology

1991-03-14

analyses of labeled model compounds, such as the protein, RuBisCO (Ribulose Bisphosphate CarboxylaselOxygenase). (3) Examine adsorption of...coverages were determined radiometrically using tritiated RuBisCO . Although natural thin films were detectable using Raman scattering techniques...optical, electrochemical, and radiometric techniques and the protein RuBisCO as a model adsorbate on titanium, copper, and iron, we have been able to

Membrane biofouling mechanism in an aerobic granular reactor degrading 4-chlorophenol.

PubMed

Buitrón, Germán; Moreno-Andrade, Iván; Arellano-Badillo, Víctor M; Ramírez-Amaya, Víctor

2014-01-01

The membrane fouling of an aerobic granular reactor coupled with a submerged membrane in a sequencing batch reactor (SBR) was evaluated. The fouling analysis was performed by applying microscopy techniques to determine the morphology and structure of the fouling layer on a polyvinylidene fluoride membrane. It was found that the main cause of fouling was the polysaccharide adsorption on the membrane surface, followed by the growth of microorganisms to form a biofilm.

Fluorogel elastomers with tunable transparency, elasticity, shape-memory, and antifouling properties

DOE PAGES

Yao, Xi; Dunn, Stuart S.; Kim, Philseok; ...

2014-03-18

In this study, omniphobic fluorogel elastomers were prepared by photocuring perfluorinated acrylates and a perfluoropolyether crosslinker. By tuning either the chemical composition or the temperature that control the crystallinity of the resulting polymer chains, a broad range of optical and mechanical properties of the fluorogel can be achieved. After infusing with fluorinated lubricants, the fluorogels showed excellent resistance to wetting by various liquids and anti-biofouling behavior, while maintaining cytocompatiblity.

Evaluation of Glider Coatings Against Biofouling for Improved Flight Performance

DTIC Science & Technology

2011-08-17

and used to conduct assays of survivorship with approximately 100 nauplii larvae ofArtemia sp. (brine shrimp ). The larvae were exposed to the...seal (D). These coatings showed higher mortality of brine shrimp as well as 100% mortality of cypris larvae during the settlement assay which...brine shrimp compared to the glass control; however these did not inhibit settlement and were evidently not toxic to the cypris larvae . All other

Materials Approach to Dissecting Surface Responses in the Attachment Stages of Biofouling Organisms

DTIC Science & Technology

2016-04-25

their settlement behavior in regards to the coating surfaces. 5) Multivariate statistical analysis was used to examine the effect (if any) of the...applied to glass rods and were deployed in the field to evaluate settlement preferences. Canonical Analysis of Principal Coordinates were applied to...the influence of coating surface properties on the patterns in settlement observed in the field in the extension of this work over the coming year

Corrosion and Biofouling of OTEC System Surfaces - Design Factors

DTIC Science & Technology

1978-11-01

condition between different areas on a given member can lead to accelerated attack by a differential envirornment cell . These differences can be...resistance. As shown in Figure 1, -. gal- vanic cell is essentially a battery/load system. When the intermetallic resistance, R1 , or the environmental...members of a couple should be maximized when possible. Also, insulating or high resistance F bushings, etc., can reduce or el4 !.minate galvanic corrosion

Biofouling and Design of a Biomimetic Hull-Grooming Tool

DTIC Science & Technology

2007-09-14

have barred the use of organotin compounds such as tributyltin ( TBT ) and copper-based paints, which are currently used by the Navy and have become...copper into the water, killing the fouling organisms. There is new research in biomimetic polymers that deter fouling, but are non- toxic . These polymers...is new research in biomimetic polymers that deter fouling, but are non- toxic . These polymers are rigidly attached to the hull surface extending

Self-Replenishing Vascularized Fouling-Release Surfaces

DTIC Science & Technology

2014-01-01

similar results. Surfaces submerged for 12 days in static cultures of B. braunii, a green microalga known for its potential in the algae biofuels...Technol. 2004, 32, 219−222. (12) Kirschner, C. M.; Brennan, A. B. Bio -Inspired Antifouling Strategies. Annu. Rev. Mater. Res. 2012, 42, 211−229. (13...Release from Fouling Release Coatings. Biofouling 2000, 15, 73−81. (25) Liu, K.; Jiang, L. Bio -Inspired Self-Cleaning Surfaces. Annu. Rev. Mater. Res

Psychosocial Correlates of Clinicians' Prescription Drug Monitoring Program Utilization.

PubMed

Pugliese, John A; Wintemute, Garen J; Henry, Stephen G

2018-05-01

The purpose of this study is to extend prior research on barriers to use of a prescription drug monitoring program by examining psychosocial correlates of intended use among physicians and pharmacists. Overall, 1,904 California physicians and pharmacists responded to a statewide survey (24.1% response rate) from August 2016 to January 2017. Participants completed an online survey examining attitudes toward prescription drug misuse and abuse, prescribing practices, prescription drug monitoring program design and ease of use, professional obligations, and normative beliefs regarding prescription drug monitoring program use. Data were analyzed in 2017. Perceived prescription drug monitoring program usefulness and normative beliefs fully mediated the relationship between concern about prescription drug abuse and intentions to use the prescription drug monitoring program. Clinicians' sense of professional and moral obligation to use the prescription drug monitoring program was unrelated to intention to use the prescription drug monitoring program despite a positive relationship with concern about misuse and abuse. Compared with physicians, pharmacists reported greater concern about prescription drug misuse, greater professional and moral obligation to use prescription drug monitoring program, and greater rating of prescription drug monitoring program usefulness. Interventions that target normative beliefs surrounding prescription drug monitoring program use and how to use prescription drug monitoring programs effectively are likely to be more effective than those that target professional obligations or moralize to the medical community. Published by Elsevier Inc.

Microbial Monitoring from the Frontlines to Space: Department of Defense Small Business Innovation Research Technology Aboard the International Space Station

NASA Technical Reports Server (NTRS)

Oubre, Cherie M.; Khodadad, Christina L.; Castro, Victoria A.; Ott, C. Mark; Flint, Stephanie; Pollack, Lawrence P.; Roman, Monserrate C.

2017-01-01

The RAZOR (trademark) EX, a quantitative Polymerase Chain Reaction (qPCR) instrument, is a portable, ruggedized unit that was designed for the Department of Defense (DoD) with its reagent chemistries traceable to a Small Business Innovation Research (SBIR) contract beginning in 2002. The PCR instrument's primary function post 9/11 was to enable frontline soldiers and first responders to detect biological threat agents and bioterrorism activities in remote locations to include field environments. With its success for DoD, the instrument has also been employed by other governmental agencies including Department of Homeland Security (DHS). The RAZOR (Trademark) EX underwent stringent testing by the vendor, as well as through the DoD, and was certified in 2005. In addition, the RAZOR (trademark) EX passed DHS security sponsored Stakeholder Panel on Agent Detection Assays (SPADA) rigorous evaluation in 2011. The identification and quantitation of microbial pathogens is necessary both on the ground as well as during spaceflight to maintain the health of astronauts and to prevent biofouling of equipment. Currently, culture-based monitoring technology has been adequate for short-term spaceflight missions but may not be robust enough to meet the requirements for long-duration missions. During a NASA-sponsored workshop in 2011, it was determined that the more traditional culture-based method should be replaced or supplemented with more robust technologies. NASA scientists began investigating innovative molecular technologies for future space exploration and as a result, PCR was recommended. Shortly after, NASA sponsored market research in 2012 to identify and review current, commercial, cutting edge PCR technologies for potential applicability to spaceflight operations. Scientists identified and extensively evaluated three candidate technologies with the potential to function in microgravity. After a thorough voice-of-the-customer trade study and extensive functional and safety evaluations, the RAZOR (trademark) EX PCR instrument(Bio-Fire Defense, Salt Lake City, UT) was selected as the most promising current technology for spaceflight monitoring applications.

Hypoxia monitoring activities within the FP7 EU-project HYPOX: diverse approaches to understand a complex phenomenon

NASA Astrophysics Data System (ADS)

Janssen, F.; Waldmann, C.; Boetius, A.

2012-04-01

Hypoxic conditions in aquatic systems and the occurrence of 'dead zones' increase worldwide due to man-made eutrophication and global warming with consequences for biodiversity, ecosystem functions and services such as fisheries, aquaculture and tourism. Monitoring of hypoxia and its consequences has to (1) account for the appropriate temporal and spatial scales, (2) separate anthropogenic from natural drivers and long-term trends from natural variations, (3) assess ecosystem response, (4) use modeling tools for generalization and prediction, and (5) share data and obtained knowledge. In 2009 the EU FP7 project HYPOX (www.hypox.net) started out as a pioneering attempt to improve and integrate hypoxia observation capacities addressing these requirements. Target ecosystems selected for HYPOX cover a broad range of settings (e.g., hydrography, oxygenation status, biological activity, anthropogenic impact) and differ in their sensitivity towards change. Semi-enclosed basins with permanent anoxia (Black Sea, Baltic Sea), are included as well as seasonally or locally hypoxic land-locked systems (fjords, lagoons, lakes) and open ocean systems with high sensitivity to global warming (North Atlantic - Arctic transition). Adopted monitoring approaches involve autonomous, cabled, and shipboard instruments and include static and profiling moorings, benthic observatories, drifters, as well as classical CTD surveys. In order to improve observatory performance, project activities encompass developments of oxygen sensors as well as calibration procedures and technologies to reduce biofouling. Modeling and data assimilation are used to synthesize findings, to obtain an in-depth understanding of hypoxia causes and consequences, and to improve forecasting capacities. For integration of the collected information into a global oxygen observing system, results are disseminated through the HYPOX portal following GEOSS data sharing principles. This presentation will give an overview of the scientific approach of HYPOX and highlight some key results comprising findings from individual ecosystems and indentified general patterns. The driving forces that lead to hypoxia are assessed as well as consequences of oxygen depletion for aquatic life and biogeochemical processes.

Epifauna dynamics at an offshore foundation--implications of future wind power farming in the North Sea.

PubMed

Krone, Roland; Gutow, Lars; Joschko, Tanja J; Schröder, Alexander

2013-04-01

In the light of the introduction of thousands of large offshore wind power foundations into the North Sea within the next decades, this manuscript focuses on the biofouling processes and likely reef effects. The study explores the macrozoobenthos (biofouling) colonization at an offshore platform which is comparable to offshore wind turbine foundations. A total of 183 single samples were taken and the parameters water depth and time were considered comparing biofouling masses and communities. The blue mussel Mytilus edulis, Anthozoa and the Amphipoda Jassa spp. were the dominant species. The community from the 1 m zone and those from the 5 and 20-28 m zones can clearly be differentiated. The 10 m zone community represents the transition between the M. edulis dominated 1 m and 5 m zones and the Anthozoa dominated 20-28 m zone. In the future offshore wind farms, thousands of wind turbine foundations will provide habitat for a hard bottom fauna which is otherwise restricted to the sparse rocky habitats scattered within extensive sedimentary soft bottoms of the German Bight. However, offshore wind power foundations cannot be considered natural rock equivalents as they selectively increase certain natural hard bottom species. The surface of the construction (1280 m²) was covered by an average of 4300 kg biomass. This foundation concentrates on its footprint area (1024 m²) 35 times more macrozoobenthos biomass than the same area of soft bottom in the German exclusive economic zone (0.12 kg m(-2)), functioning as a biomass hotspot. Concerning the temporal biomass variation, we assume that at least 2700 kg biomass was exported on a yearly basis. 345 × 10(4) single mussel shells of different sizes were produced during the study period. It is anticipated that the M. edulis abundance will increase in the North Sea due to the expansion of the offshore wind farm development. This will result in the enhanced production of secondary hard substrate (mussel shells) and its associated fauna and will intensify filtration rates of the seawater. This predicted ecological system change is coined the 'Mytilusation' of the German Bight. Copyright © 2012 Elsevier Ltd. All rights reserved.

An alternative cost-effective image processing based sensor for continuous turbidity monitoring

NASA Astrophysics Data System (ADS)

Chai, Matthew Min Enn; Ng, Sing Muk; Chua, Hong Siang

2017-03-01

Turbidity is the degree to which the optical clarity of water is reduced by impurities in the water. High turbidity values in rivers and lakes promote the growth of pathogen, reduce dissolved oxygen levels and reduce light penetration. The conventional ways of on-site turbidity measurements involve the use of optical sensors similar to those used in commercial turbidimeters. However, these instruments require frequent maintenance due to biological fouling on the sensors. Thus, image processing was proposed as an alternative technique for continuous turbidity measurement to reduce frequency of maintenance. The camera was kept out of water to avoid biofouling while other parts of the system submerged in water can be coated with anti-fouling surface. The setup developed consisting of a webcam, a light source, a microprocessor and a motor used to control the depth of a reference object. The image processing algorithm quantifies the relationship between the number of circles detected on the reference object and the depth of the reference object. By relating the quantified data to turbidity, the setup was able to detect turbidity levels from 20 NTU to 380 NTU with measurement error of 15.7 percent. The repeatability and sensitivity of the turbidity measurement was found to be satisfactory.

The effect of biofouling in simulated Ocean Thermal Energy Conversion (OTEC) evaporator tubes at a potential site in Puerto Rico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasscer, D.S.; Morgan, T.O.; Tosteson, T.R.

1980-12-01

Since 29 January 1980, continuous flow of ocean surface water has been maintained through simulated Ocean Thermal Energy Conversion (OTEC) evaporator tubes in order to determine in situ, long-term effects of microbiofouling on heat exchanger efficiency. The experimental apparatus consists of two aluminum and two titanium modules mounted on a research platform moored at the potential OTEC site off Punta Tuna, Puerto Rico. The fouling resistance (R /SUB f/ ), a relative measure of heat transfer efficiency, is being monitored regularly, and the units have been cleaned four times. Postcleaning fouling rates (dR /SUB f/ /dt) for the aluminum unitsmore » have not changed significantly but are considerably higher than the initial fouling rates. At first, post-cleaning fouling rates for the titanium units were less than for the aluminum units, but this value has been progressively increasing and now all units are fouling at approximately the same rate. Cleaning with manually operated M.A.N. brushes did not reduce R /SUB f/ to zero. On four occasions, flow velocity through the units has been increased. Results from these experiments suggest that initially the fouling layer is easily dislodged from the tube surface but that, with time, it becomes more firmly attached.« less

A covalently cross-linked gel derived from the epidermis of the pilot whale Globicephala melas.

PubMed

Baum, C; Fleischer, L-G; Roessner, D; Meyer, W; Siebers, D

2002-01-01

The rheological properties of the stratum corneum of the pilot whale (Globicephala melas) were investigated with emphasis on their significance to the self-cleaning abilities of the skin surface smoothed by a jelly material enriched with various hydrolytic enzymes. The gel formation of the collected fluid was monitored by applying periodic-harmonic oscillating loads using a stress-controlled rheometer. In the mechanical spectrum of the gel, the plateau region of the storage modulus G' (<1200 Pa) and the loss modulus G" (>120 Pa) were independent of frequency (omega = 43.98 to 0.13 rad x s(-1), tau = 15 Pa, T = 20 degrees C), indicating high elastic performance of a covalently cross-linked viscoelastic solid. In addition, multi-angle laser light scattering experiments (MALLS) were performed to analyse the potential time-dependent changes in the weight-average molar mass of the samples. The observed increase showed that the gel formation is based on the assembly of covalently cross-linked aggregates. The viscoelastic properties and the shear resistance of the gel assure that the enzyme-containing jelly material smoothing the skin surface is not removed from the stratum corneum by shear regimes during dolphin jumping. The even skin surface is considered to be most important for the self-cleaning abilities of the dolphin skin against biofouling.

Developing cDNA Libraries of Receptors Involved in the Recruitment of the Biofouling Tubeworm Hydroides elegans

DTIC Science & Technology

2014-06-12

Transcriptome, Hydroides elegans, Next Generation Sequencing, Illumina HiSeq, PacBio SMRT, Biofilm , Metamorphosis 16. SECURITY CLASSIFICATION OF: a...to a bacterial cue from a bacterial biofilm . Recently, this cue has been identified to be a phage-tail like bacteriocin produced by the bacterium...submitted to the Huntsman Cancer Institute at the University of Utah and the subsequent isolation of mRNA was used for Illumina HiSeq 101 paired end

Structure-Property Relationships of Silicone Biofouling-Release Coatings: Effect of Silicone Network Architecture on Pseudobarnacle Attachment Strengths

DTIC Science & Technology

2003-01-01

ambient conditions prior to testing. A masterbatch for hydrosilylation-curable model systems was prepared by combining 200 g of hexamethydisilazane treated...fumed silica and 800 g of vinylterminated polydimethylsiloxane (equivalent weight ¼ 4111). The masterbatch was combined with additional vinyl polymer...followed by 10ml of Karstedt’s catalyst (10.9% Pt, 4.8mmol Pt). The amounts of masterbatch , linear vinyl, linear hydride, and crosslinkable hydride

Biofouling of Several Marine Diesel Fuels

DTIC Science & Technology

2011-03-01

Sons Ltd Hughes, J.M, G.W. Mushrush, and D.R. Hardy. 2002. Lubricity-enhancing properties of soy oil when used as a blending stock for middle...biomass production (right) with HSD, ULSD, Algae, NSWCCD-61-TR-2011/08 iv and 5% Bio fuels, and neat tall oil fatty acids (TOFA) over 11 days...is produced from oils and fats from plants and animals, via the transesterification of fatty acids with methanol to produce fatty acid methyl esters

Molecular Analysis of Tube Cement of the Biofouling Tubeworm Hydroides elegans

DTIC Science & Technology

2016-03-08

fouler that secretes a tube and strong cement. Little is known about the composition of either of these structures or the genes encoding them. We...the tubeworms cannot attach or can attach only weakly. Cements of H. elegans are secreted during two separate stages of metamorphosis and growth. The...first cements are secreted from the post-trochal region of settling larvae and is a component of a proteinaceous primary tube. This sticky tube is

In-Water Treatment of Biofouling in Internal Systems: Field Validation of Quaternary Ammonium Compound (QAC) Chemical Treatment Protocols

DTIC Science & Technology

2013-06-01

accumulate and shelter sessile and mobile marine species. Fouling in sea chests and sea water pipework is also an operational issue for marine engineers ...pipework is also an operational issue for marine engineers , as it restricts water flow to essential vessel systems and may enhance biocorrosion [18, 19...subtidal marine communities worldwide and are considered as key species and important habitat engineers in benthic communities [30]. They possess high

Non-Indigenous Marine Species (NIMS) in Biofouling on RAN Vessels: Threat Analysis

DTIC Science & Technology

2015-09-01

zebra Dechaineux (Nov 2001) & (Aug 2003) First recorded at Botany Bay in 1998 Metopograpsus messor Sydney (Aug 2003) Not recorded Pachygrapsus...Wollongong, Port Botany and Port Kembla) (Pollard and Pethebridge, 2002b). M. rosa has been designated as an Introduced Marine Pest (IMP) by the National... Botany Bay, NSW in 1990 (Lewis et al., 2006), and is known to co- occur with S. taeniatus, a species common along the eastern Australian coastline

A novel approach for UV-patterning with binary polymer brushes.

PubMed

Li, Lifu; Nakaji-Hirabayashi, Tadashi; Kitano, Hiromi; Ohno, Kohji; Saruwatari, Yoshiyuki; Matsuoka, Kazuyoshi

2018-01-01

A mixed self-assembled monolayer (SAM) of an initiator (3-(2-bromo-2-isobutyryloxy)propyl triethoxysilane) for atom transfer radical polymerization (ATRP) and an agent (6-(triethoxysilyl)hexyl 2-(((methylthio)carbonothioyl)thio)-2-phenylacetate) for reversible addition-fragmentation chain transfer (RAFT) polymerization was constructed on the surface of a silicon wafer or glass plate by a silane coupling reaction. When a UV light at 254nm was irradiated at the mixed SAM through a photomask, the surface density of the bromine atom at the end of BPE in the irradiated region was drastically reduced by UV-driven scission of the BrC bond, as observed by X-ray photoelectron spectroscopy. Consequently, the surface-initiated (SI)-ATRP of 2-ethylhexyl methacrylate (EHMA) was used to easily construct the poly(EHMA) (PEHMA) brush domain. Subsequently, SI-RAFT polymerization of a zwitterionic vinyl monomer, carboxymethyl betaine (CMB), was performed. Using the sequential polymerization, the PCMB and PEHMA brush domains on the solid substrate could be very easily patterned. Patterning proteins and cells with the binary polymer brush is expected because the PCMB brush indicated strong suppression of protein adsorption and cell adhesion, and the PEHMA brush had non-polar properties. This technique is very simple and useful for regulating the shape and size of bio-fouling and anti-biofouling domains on solid surfaces. Copyright © 2017 Elsevier B.V. All rights reserved.

Inhibition of biofilm formation by D-tyrosine: Effect of bacterial type and D-tyrosine concentration.

PubMed

Yu, Cong; Li, Xuening; Zhang, Nan; Wen, Donghui; Liu, Charles; Li, Qilin

2016-04-01

D-Tyrosine inhibits formation and triggers disassembly of bacterial biofilm and has been proposed for biofouling control applications. This study probes the impact of D-tyrosine in different biofilm formation stages in both G+ and G- bacteria, and reveals a non-monotonic correlation between D-tyrosine concentration and biofilm inhibition effect. In the attachment stage, cell adhesion was studied in a flow chamber, where D-tyrosine caused significant reduction in cell attachment. Biofilms formed by Pseudomonas aeruginosa and Bacillus subtilis were characterized by confocal laser scanning microscopy as well as quantitative analysis of cellular biomass and extracellular polymeric substances. D-Tyrosine exhibited strong inhibitive effects on both biofilms with an effective concentration as low as 5 nM; the biofilms responded to D-tyrosine concentration change in a non-monotonic, bi-modal pattern. In addition, D-tyrosine showed notable and different impact on EPS production by G+ and G- bacteria. Extracellular protein was decreased in P. aeruginosa biofilms, but increased in those of B. subtilis. Exopolysaccharides production by P. aeruginosa was increased at low concentrations and reduced at high concentrations while no impact was found in B. subtilis. These results suggest that distinct mechanisms are at play at different D-tyrosine concentrations and they may be species specific. Dosage of D-tyrosine must be carefully controlled for biofouling control applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

More Efficient Media Design for Enhanced Biofouling Control in a Membrane Bioreactor: Quorum Quenching Bacteria Entrapping Hollow Cylinder.

PubMed

Lee, Sang H; Lee, Seonki; Lee, Kibaek; Nahm, Chang H; Kwon, Hyeokpil; Oh, Hyun-Suk; Won, Young-June; Choo, Kwang-Ho; Lee, Chung-Hak; Park, Pyung-Kyu

2016-08-16

Recently, membrane bioreactors (MBRs) with quorum quenching (QQ) bacteria entrapping beads have been reported as a new paradigm in biofouling control because, unlike conventional post-biofilm control methods, bacterial QQ can inhibit biofilm formation through its combined effects of physical scouring of the membrane and inhibition of quorum sensing (QS). In this study, using a special reporter strain (Escherichia coli JB525), the interaction between QS signal molecules and quorum quenching bacteria entrapping beads (QQ-beads) was elucidated through visualization of the QS signal molecules within a QQ-bead using a fluorescence microscope. As a result, under the conditions considered in this study, the surface area of QQ-media was likely to be a dominant parameter in enhancing QQ activity over total mass of entrapped QQ bacteria because QQ bacteria located near the core of a QQ-bead were unable to display their QQ activities. On the basis of this information, a more efficient QQ-medium, a QQ hollow cylinder (QQ-HC), was designed and prepared. In batch experiments, QQ-HCs showed greater QQ activity than QQ-beads as a result of their higher surface area and enhanced physical washing effect because of their larger impact area against the membrane surface. Furthermore, it was shown that such advantages of QQ-HCs resulted in more effective mitigation of membrane fouling than from QQ-beads in lab-scale continuous MBRs.

Biofouling and microbial corrosion problem in the thermo-fluid heat exchanger and cooling water system of a nuclear test reactor.

PubMed

Rao, T S; Kora, Aruna Jyothi; Chandramohan, P; Panigrahi, B S; Narasimhan, S V

2009-10-01

This article discusses aspects of biofouling and corrosion in the thermo-fluid heat exchanger (TFHX) and in the cooling water system of a nuclear test reactor. During inspection, it was observed that >90% of the TFHX tube bundle was clogged with thick fouling deposits. Both X-ray diffraction and Mossbauer analyses of the fouling deposit demonstrated iron corrosion products. The exterior of the tubercle showed the presence of a calcium and magnesium carbonate mixture along with iron oxides. Raman spectroscopy analysis confirmed the presence of calcium carbonate scale in the calcite phase. The interior of the tubercle contained significant iron sulphide, magnetite and iron-oxy-hydroxide. A microbiological assay showed a considerable population of iron oxidizing bacteria and sulphate reducing bacteria (10(5) to 10(6) cfu g(-1) of deposit). As the temperature of the TFHX is in the range of 45-50 degrees C, the microbiota isolated/assayed from the fouling deposit are designated as thermo-tolerant bacteria. The mean corrosion rate of the CS coupons exposed online was approximately 2.0 mpy and the microbial counts of various corrosion causing bacteria were in the range 10(3) to 10(5) cfu ml(-1) in the cooling water and 10(6) to 10(8) cfu ml(-1) in the biofilm.

Direct observation of bacterial deposition onto clean and organic-fouled polyamide membranes.

PubMed

Subramani, Arun; Huang, Xiaofei; Hoek, Eric M V

2009-08-01

Nanofiltration (NF) and reverse osmosis (RO) membranes are commonly applied to produce highly purified water from municipal wastewater effluents. In these applications, biofouling limits overall process performance and increases the cost of operation. Initial bacteria adhesion onto a membrane surface is a critical early step in the overall process of membrane biofouling. However, adsorption of effluent organic matter onto the membrane may precede bacterial deposition and change membrane surface properties. Herein we employed direct microscopic observation to elucidate mechanisms governing bacterial cell deposition onto clean and organic-fouled NF and RO membranes. Bovine serum albumin (BSA) and alginic acid (AA) were used as models for protein and polysaccharide rich organic matter in secondary wastewater effluents. In all experiments, organic fouling increased membrane hydraulic resistance and salt rejection, in addition to interfacial hydrophilicity and roughness. Even though surface hydrophilicity increased, the rougher surfaces presented by organic-fouled membranes produced nano-scale features that promoted localized bacterial deposition. An extended DLVO analysis of bacterial cells and membrane surface properties suggested that bacterial deposition correlated most strongly with the Lewis acid-base free energy of adhesion and root mean square (RMS) roughness, whereas van der Waals and electrostatic free energies were weakly correlated. This was true for both clean and organic-fouled membranes. Bacterial deposition rates were clearly influenced by an antagonistic interplay between macroscopic surface hydrophilicity and nano-scale surface roughness.

Modification of silicone elastomer with zwitterionic silane for durable antifouling properties.

PubMed

Yeh, Shiou-Bang; Chen, Chien-Sheng; Chen, Wen-Yih; Huang, Chun-Jen

2014-09-30

Biofouling on medical devices generally causes adverse complications, such as thrombosis, infection, and pathogenic calcification. Silicone is a widely used material for medical applications. Its surface modification typically encounters undesirable "hydrophobic recovery", leading to deterioration of surface engineering. In this study, we developed a stable superhydrophilic zwitterionic interface on polydimethylsiloxane (PDMS) elastomer by covalent silanization of sulfobetaine silane (SBSi) to resist nonspecific adsorption of bacteria, proteins, and lipids. SBSi is a zwitterionic organosilane assembly, enabling resisting surface reconstruction by forming a cross-linked network and polar segregation. Surface elemental composition was confirmed by X-ray photoelectron spectroscopy (XPS), and the long-term stability of modification was accessed using a contact angle goniometer. The biofouling tests were carried out by exposing substrates to bacterial, protein, and lipid solutions, revealing the excellent bioinertness of SBSi-tailored PDMS, even after 30 day storage in ambient. For the real-world application, we modified commercially available silicone hydrogel contact lenses with developed zwitterionic silane, presenting its antibacterial adhesion property. Moreover, the cytotoxicity of SBSi was accessed with NIH-3T3 fibroblast by the MTT assay, showing negligible cytotoxicity up to a concentration of 5 mM. Consequently, the strategy of surface engineering in this work can effectively retard the "hydrophobic recovery" occurrence and can be applied to other silicone-based medical devices in a facile way.

Robust fabrication of thin film polyamide-TiO2 nanocomposite membranes with enhanced thermal stability and anti-biofouling propensity.

PubMed

Khorshidi, Behnam; Biswas, Ishita; Ghosh, Tanushree; Thundat, Thomas; Sadrzadeh, Mohtada

2018-01-15

The development of nano-enabled composite materials has led to a paradigm shift in the manufacture of high-performance nanocomposite membranes with enhanced permeation, thermo-mechanical, and antibacterial properties. The major challenges to the successful incorporation of nanoparticles (NPs) to polymer films are the severe aggregation of the NPs and the weak compatibility of NPs with polymers. These two phenomena lead to the formation of non-selective voids at the interface of the polymer and NPs, which adversely affect the separation performance of the membrane. To overcome these challenges, we have developed a new method for the fabrication of robust TFN reverse osmosis membranes. This approach relies on the simultaneous synthesis and surface functionalization of TiO 2 NPs in an organic solvent (heptane) via biphasic solvothermal reaction. The resulting stable suspension of the TiO 2 NPs in heptane was then utilized in the interfacial (in-situ) polymerization reaction where the NPs were entrapped within the matrix of the polyamide (PA) membrane. TiO 2 NPs of 10 nm were effectively incorporated into the thin PA layer and improved the thermal stability and anti-biofouling properties of the resulting TFN membranes. These features make our synthesized membranes potential candidates for applications where the treatment of high-temperature streams containing biomaterials is desirable.

Improved antifouling potential of polyether sulfone polymeric membrane containing silver nanoparticles: self-cleaning membranes.

PubMed

Rana, Sidra; Nazar, Umair; Ali, Jafar; Ali, Qurat Ul Ain; Ahmad, Nasir M; Sarwar, Fiza; Waseem, Hassan; Jamil, Syed Umair Ullah

2018-06-01

A new strategy to enhance the antifouling potential of polyether sulfone (PES) membrane is presented. Chemically synthesized silver nanoparticles (AgNPs) were used to prepare a mixed-matrix PES membrane by the phase inversion technique. Primarily, AgNPs synthesis was confirmed by surface plasmon resonance at 410-430 nm using UV-Visible spectroscopy. X-ray diffraction analysis revealed that AgNPs were crystalline with a diameter of 21 ± 2 nm. Furthermore, PES membranes were characterized by energy dispersive X-ray spectroscopy to confirm the incorporation of AgNPs in membranes. Hydrophilicity of the membranes was enhanced, whereas roughness, mechanical strength and biofouling were relatively reduced after embedding the AgNPs. Antibacterial potential of AgNPs was evaluated for E. coli in the disc diffusion and colony-forming unit (CFU) count method. All of the membranes were assessed for antifouling activity by filtering a control dilution (10 6  CFU/ml) of E. coli and by counting CFU. Anti-biofouling activity of the membrane was observed with different concentrations of AgNPs. Maximum reduction (66%) was observed in membrane containing 1.5% of AgNPs. The addition of antibiotic ceftriaxone enhanced the antibacterial effect of AgNPs in PES membranes. Our practicable antifouling strategy may be applied to other polymeric membranes which may pave the new way to achieve sustainable and self-cleaning membrane reactors on large scale.

Mitigation of Biofilm Development on Thin-Film Composite Membranes Functionalized with Zwitterionic Polymers and Silver Nanoparticles.

PubMed

Liu, Caihong; Faria, Andreia F; Ma, Jun; Elimelech, Menachem

2017-01-03

We demonstrate the functionalization of thin-film composite membranes with zwitterionic polymers and silver nanoparticles (AgNPs) for combating biofouling. Combining hydrophilic zwitterionic polymer brushes and biocidal AgNPs endows the membrane with dual functionality: antiadhesion and bacterial inactivation. An atom transfer radical polymerization (ATRP) reaction is used to graft zwitterionic poly(sulfobetaine methacrylate) (PSBMA) brushes to the membrane surface, while AgNPs are synthesized in situ through chemical reduction of silver. Two different membrane architectures (Ag-PSBMA and PSBMA-Ag TFC) are developed according to the sequence AgNPs, and PSBMA brushes are grafted on the membrane surface. A static adhesion assay shows that both modified membranes significantly reduced the adsorption of proteins, which served as a model organic foulant. However, improved antimicrobial activity is observed for PSBMA-Ag TFC (i.e., AgNPs on top of the polymer brush) in comparison to the Ag-PSBMA TFC membrane (i.e., polymer brush on top of AgNPs), indicating that architecture of the antifouling layer is an important factor in the design of zwitterion-silver membranes. Confocal laser scanning microscopy (CLSM) imaging indicated that PSBMA-Ag TFC membranes effectively inhibit biofilm formation under dynamic cross-flow membrane biofouling tests. Finally, we demonstrate the regeneration of AgNPs on the membrane after depletion of silver from the surface of the PSBMA-Ag TFC membrane.

Highly Specific Binding on Antifouling Zwitterionic Polymer-Coated Microbeads as Measured by Flow Cytometry.

PubMed

van Andel, Esther; de Bus, Ian; Tijhaar, Edwin J; Smulders, Maarten M J; Savelkoul, Huub F J; Zuilhof, Han

2017-11-08

Micron- and nano-sized particles are extensively used in various biomedical applications. However, their performance is often drastically hampered by the nonspecific adsorption of biomolecules, a process called biofouling, which can cause false-positive and false-negative outcomes in diagnostic tests. Although antifouling coatings have been extensively studied on flat surfaces, their use on micro- and nanoparticles remains largely unexplored, despite the widespread experimental (specifically, clinical) uncertainties that arise because of biofouling. Here, we describe the preparation of magnetic micron-sized beads coated with zwitterionic sulfobetaine polymer brushes that display strong antifouling characteristics. These coated beads can then be equipped with recognition elements of choice, to enable the specific binding of target molecules. First, we present a proof of principle with biotin-functionalized beads that are able to specifically bind fluorescently labeled streptavidin from a complex mixture of serum proteins. Moreover, we show the versatility of the method by demonstrating that it is also possible to functionalize the beads with mannose moieties to specifically bind the carbohydrate-binding protein concanavalin A. Flow cytometry was used to show that thus-modified beads only bind specifically targeted proteins, with minimal/near-zero nonspecific protein adsorption from other proteins that are present. These antifouling zwitterionic polymer-coated beads, therefore, provide a significant advancement for the many bead-based diagnostic and other biosensing applications that require stringent antifouling conditions.

Highly Specific Binding on Antifouling Zwitterionic Polymer-Coated Microbeads as Measured by Flow Cytometry

PubMed Central

2017-01-01

Micron- and nano-sized particles are extensively used in various biomedical applications. However, their performance is often drastically hampered by the nonspecific adsorption of biomolecules, a process called biofouling, which can cause false-positive and false-negative outcomes in diagnostic tests. Although antifouling coatings have been extensively studied on flat surfaces, their use on micro- and nanoparticles remains largely unexplored, despite the widespread experimental (specifically, clinical) uncertainties that arise because of biofouling. Here, we describe the preparation of magnetic micron-sized beads coated with zwitterionic sulfobetaine polymer brushes that display strong antifouling characteristics. These coated beads can then be equipped with recognition elements of choice, to enable the specific binding of target molecules. First, we present a proof of principle with biotin-functionalized beads that are able to specifically bind fluorescently labeled streptavidin from a complex mixture of serum proteins. Moreover, we show the versatility of the method by demonstrating that it is also possible to functionalize the beads with mannose moieties to specifically bind the carbohydrate-binding protein concanavalin A. Flow cytometry was used to show that thus-modified beads only bind specifically targeted proteins, with minimal/near-zero nonspecific protein adsorption from other proteins that are present. These antifouling zwitterionic polymer-coated beads, therefore, provide a significant advancement for the many bead-based diagnostic and other biosensing applications that require stringent antifouling conditions. PMID:29064669

Membrane Bioreactor (MBR) Technology for Wastewater Treatment and Reclamation: Membrane Fouling

PubMed Central

Iorhemen, Oliver Terna; Hamza, Rania Ahmed; Tay, Joo Hwa

2016-01-01

The membrane bioreactor (MBR) has emerged as an efficient compact technology for municipal and industrial wastewater treatment. The major drawback impeding wider application of MBRs is membrane fouling, which significantly reduces membrane performance and lifespan, resulting in a significant increase in maintenance and operating costs. Finding sustainable membrane fouling mitigation strategies in MBRs has been one of the main concerns over the last two decades. This paper provides an overview of membrane fouling and studies conducted to identify mitigating strategies for fouling in MBRs. Classes of foulants, including biofoulants, organic foulants and inorganic foulants, as well as factors influencing membrane fouling are outlined. Recent research attempts on fouling control, including addition of coagulants and adsorbents, combination of aerobic granulation with MBRs, introduction of granular materials with air scouring in the MBR tank, and quorum quenching are presented. The addition of coagulants and adsorbents shows a significant membrane fouling reduction, but further research is needed to establish optimum dosages of the various coagulants/adsorbents. Similarly, the integration of aerobic granulation with MBRs, which targets biofoulants and organic foulants, shows outstanding filtration performance and a significant reduction in fouling rate, as well as excellent nutrients removal. However, further research is needed on the enhancement of long-term granule integrity. Quorum quenching also offers a strong potential for fouling control, but pilot-scale testing is required to explore the feasibility of full-scale application. PMID:27314394

Evaluation of pre-treatment technologies for phosphorous removal from drinking water to mitigate membrane biofouling

NASA Astrophysics Data System (ADS)

Frolova, M.; Tihomirova, K.; Mežule, L.; Rubulis, J.; Gruškeviča, K.; Juhna, T.

2017-10-01

Membranes are widely used for the treatment of various solutions. However, membrane fouling remains the limiting factor for their usage, setting biofouling as the most severe type of it. Therefore, the production of biologically stable water prior to membranes is important. Since lack of phosphorus may hinder the growth of microorganisms, the aim of this research is to evaluate the effect of microbially available phosphorus (MAP) removal via affordable water pre-treatment methods (adsorption, biofiltration, electrocoagulation) on bacterial growth. Four cylindrical reactors were installed at an artificially recharged groundwater station. Further temperature influence and carbon limitation were tested for biofiltration technology. The amount of MAP and total cell count was measured by flow cytometry. The results showed that at lower temperatures electrocoagulation performed the best, resulting in complete MAP removal (detection limit 6.27x10-3μg P l-1). Sorbent demonstrated MAP removal of 70-90%. Biomass did not have any noteworthy results at +8°C, however, at +19°C MAP removal of around 80% was achieved. Main conclusions obtained within this study are: (i) tested technologies effectively eliminate MAP levels; (ii) temperature has a significant effect on MAP removal in a bioreactor, (iii) multi-barrier approach might be necessary for better P limitation that might prolong operating time of a membrane.

Development of GUI Type On-Line Condition Monitoring Program for a Turboprop Engine Using Labview

NASA Astrophysics Data System (ADS)

Kong, Changduk; Kim, Keonwoo

2011-12-01

Recently, an aero gas turbine health monitoring system has been developed for precaution and maintenance action against faults or performance degradations of the advanced propulsion system which occurs in severe environments such as high altitude, foreign object damage particles, hot and heavy rain and snowy atmospheric conditions. However to establish this health monitoring system, the online condition monitoring program is firstly required, and the program must monitor the engine performance trend through comparison between measured engine performance data and base performance results calculated by base engine performance model. This work aims to develop a GUI type on-line condition monitoring program for the PT6A-67 turboprop engine of a high altitude and long endurance operation UAV using LabVIEW. The base engine performance of the on-line condition monitoring program is simulated using component maps inversely generated from the limited performance deck data provided by engine manufacturer. The base engine performance simulation program is evaluated because analysis results by this program agree well with the performance deck data. The proposed on-line condition program can monitor the real engine performance as well as the trend through precise comparison between clean engine performance results calculated by the base performance simulation program and measured engine performance signals. In the development phase of this monitoring system, a signal generation module is proposed to evaluate the proposed online monitoring system. For user friendly purpose, all monitoring program are coded by LabVIEW, and monitoring examples are demonstrated using the proposed GUI type on-condition monitoring program.

Instrument packages to study long-term sediment transport processes in a shallow bay

USGS Publications Warehouse

Strahle, William J.; Martini, Marinna A.; Davis, Ray E.

1994-01-01

Pressure and near-surface and near-bottom measurements of current, temperature, salinity and light transmission were required in Mobile Bay, a 3 m deep estuary on the Gulf of Mexico. This environment presented several obstacles to obtaining long term observations. Boat traffic, soft estuary bottom, heavy biofouling, rapid sample rates and large data storage were overcome by using instrumentation techniques that are applicable to other estuary systems. Nearly two years of continuous data was collected.

Examination of Chemical Adsorption and Marine Biofouling on Metal Surfaces Using Raman Scattering Techniques and Electrochemical Impedance Spectroscopy

DTIC Science & Technology

1989-01-13

aromatic amino acids adsorbed on conditioned Ag electrodes in 0.1 N KCl. A. tryptophan. B. phenylalanine. Ribulose biphosphate carboxylase ( RuBisCo ) has...Preliminary runs with a silver electrode, UV-oxidized seawater, and a putative fouling protein, Ribulose 1,5 biphosphate carboxylase ( RuBisCo ) have been...completed. Prior to adding RuBisCo to the system, a series of runs were made to establish functionality of the cell and system parameters. The system

Use of a Nafion Membrane Probe for Quick, On-the-Spot Determination of Ionic Copper Contamination Levels in Natural Waters

DTIC Science & Technology

2000-01-01

avert an environmental problem. The developed sensor uses the perfluorinated ionomeric film, Nation 117. This film has a Teflon matrix with sulfate...Dexter et al 1975, Dexter 1978). Once the surface is organically "wet" then bacteria can attach (reversible sorption ) but are removed easily (Marshall... sorption ) and the primary biofouling film forms (Little 1984). This primary film becomes attractive to algae and protozoa as well as attracting detritus

Reactive Inkjet Printing of Biocompatible Enzyme Powered Silk Micro-Rockets.

PubMed

Gregory, David A; Zhang, Yu; Smith, Patrick J; Zhao, Xiubo; Ebbens, Stephen J

2016-08-01

Inkjet-printed enzyme-powered silk-based micro-rockets are able to undergo autonomous motion in a vast variety of fluidic environments including complex media such as human serum. By means of digital inkjet printing it is possible to alter the catalyst distribution simply and generate varying trajectory behavior of these micro-rockets. Made of silk scaffolds containing enzymes these micro-rockets are highly biocompatible and non-biofouling. © 2016 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Spatial and Temporal Control of Chemical Structure for Biofouling Resistant, High Fouling Release Surfaces

DTIC Science & Technology

2014-06-02

thick-walled glass reactors fitted with ACE-threads under an argon atmosphere. The reactors were dried under vacuum then refilled with argon five times...were settled in individual dishes containing 10 ml of suspension at ~20°C on the laboratory benches. After 2 h the slides were exposed to a submerged ...and D20). This was done in order to see how the surfaces rearranged themselves after prolonged periods submerged in water, as would be the case on

Volunteer water monitoring: A guide for state managers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-08-01

Contents: executive summary; volunteers in water monitoring; planning a volunteer monitoring program; implementing a volunteer monitoring program; providing credible information; costs and funding; and descriptions of five successful programs.

40 CFR 264.99 - Compliance monitoring program.

Code of Federal Regulations, 2011 CFR

2011-07-01

... be based on a compliance monitoring program developed to meet the requirements of this section. (i... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Compliance monitoring program. 264.99... Releases From Solid Waste Management Units § 264.99 Compliance monitoring program. An owner or operator...

Drag Reduction On Multiscale Superhydrophobic Surfaces

NASA Astrophysics Data System (ADS)

Jenner, Elliot; Barbier, Charlotte; D'Urso, Brian

2013-11-01

Fluid drag reduction is of great interest in a variety of fields, including hull engineering, microfluidics, and drug delivery. We fabricated samples with multi-scale superhydrophobic surfaces, which consist of hexagonally self-ordered microscopic spikes grown via anodization on macroscopic grooves cut in aluminum. The hydrodynamic drag properties were studied with a cone-and-plate rheometer, showing significant drag reduction near 15% in turbulent flow and near 30% in laminar flow. In addition to these experiments, numerical simulations were performed in order to estimate the slip length at high speeds. Furthermore, we will report on the progress of experiments with a new type of surface combining superhydrophobic surfaces like those discussed above with Slippery Liquid Infused Porous Surfaces (SLIPS), which utilize an oil layer to create a hydrophobic self-repairing surface. These ``Super-SLIPS'' may combine the best properties of both superhydrophobic surfaces and SLIPS, by combining a drag reducing air-layer and an oil layer which may improve durability and biofouling resistance. This research was supported by the ORNL Seed Money Program. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the U.S. Dept. of Energy under contract DE-AC05-00OR22725.

Coupling plant growth and waste recycling systems in a controlled life support system (CELSS)

NASA Technical Reports Server (NTRS)

Garland, Jay L.

1992-01-01

The development of bioregenerative systems as part of the Controlled Ecological Life Support System (CELSS) program depends, in large part, on the ability to recycle inorganic nutrients, contained in waste material, into plant growth systems. One significant waste (resource) stream is inedible plant material. This research compared wheat growth in hydroponic solutions based on inorganic salts (modified Hoagland's) with solutions based on the soluble fraction of inedible wheat biomass (leachate). Recycled nutrients in leachate solutions provided the majority of mineral nutrients for plant growth, although additions of inorganic nutrients to leachate solutions were necessary. Results indicate that plant growth and waste recyling systems can be effectively coupled within CELSS based on equivalent wheat yield in leachate and Hoagland solutions, and the rapid mineralization of waste organic material in the hydroponic systems. Selective enrichment for microbial communities able to mineralize organic material within the leachate was necessary to prevent accumulation of dissolved organic matter in leachate-based solutions. Extensive analysis of microbial abundance, growth, and activity in the hydroponic systems indicated that addition of soluble organic material from plants does not cause excessive microbial growth or 'biofouling', and helped define the microbially-mediated flux of carbon in hydroponic solutions.

Life Support Systems Microbial Challenges

NASA Technical Reports Server (NTRS)

Roman, Monsi C.

2010-01-01

Many microbiological studies were performed during the development of the Space Station Water Recovery and Management System from1990-2009. Studies include assessments of: (1) bulk phase (planktonic) microbial population (2) biofilms, (3) microbially influenced corrosion (4) biofouling treatments. This slide presentation summarizes the studies performed to assess the bulk phase microbial community during the Space Station Water Recovery Tests (WRT) from 1990 to 1998. This report provides an overview of some of the microbiological analyses performed during the Space Station WRT program. These tests not only integrated several technologies with the goal of producing water that met NASA s potable water specifications, but also integrated humans, and therefore human flora into the protocols. At the time these tests were performed, not much was known (or published) about the microbial composition of these types of wastewater. It is important to note that design changes to the WRS have been implemented over the years and results discussed in this report might be directly related to test configurations that were not chosen for the final flight configuration. Results microbiological analyses performed Conclusion from the during the WRT showed that it was possible to recycle water from different sources, including urine, and produce water that can exceed the quality of municipally produced water.

Understanding Program Monitoring: The Relationships among Outcomes, Indicators, Measures, and Targets. REL 2014-011

ERIC Educational Resources Information Center

Malone, Nolan; Mark, Lauren; Narayan, Krishna

2014-01-01

This guide offers educators, program managers, administrators, and researchers a resource for building capacity for monitoring program outcomes. It provides concise definitions of program monitoring components and a framework for assessing program progress. Examples demonstrate the relationships among program components: outcomes, indicators,…

Establishing a national biological laboratory safety and security monitoring program.

PubMed

Blaine, James W

2012-12-01

The growing concern over the potential use of biological agents as weapons and the continuing work of the Biological Weapons Convention has promoted an interest in establishing national biological laboratory biosafety and biosecurity monitoring programs. The challenges and issues that should be considered by governments, or organizations, embarking on the creation of a biological laboratory biosafety and biosecurity monitoring program are discussed in this article. The discussion focuses on the following questions: Is there critical infrastructure support available? What should be the program focus? Who should be monitored? Who should do the monitoring? How extensive should the monitoring be? What standards and requirements should be used? What are the consequences if a laboratory does not meet the requirements or is not willing to comply? Would the program achieve the results intended? What are the program costs? The success of a monitoring program can depend on how the government, or organization, responds to these questions.

A Review of the Foreign-body Response to Subcutaneously-implanted Devices: The Role of Macrophages and Cytokines in Biofouling and Fibrosis

PubMed Central

Kenneth Ward, W.

2008-01-01

The biological response to implanted biomaterials in mammals is a complex series of events that involves many biochemical pathways. Shortly after implantation, fibrinogen and other proteins bind to the device surface, a process known as biofouling. Macrophages then bind to receptors on the proteins, join into multinucleated giant cells, and release transforming growth factor β and other inflammatory cytokines. In response to these signals, quiescent fibroblasts are transformed into myofibroblasts, which synthesize procollagen via activation of Smad mediators. The procollagen becomes crosslinked after secretion into the extracellular space. Mature crosslinked collagen and other extracellular matrix proteins gradually contribute to formation of a hypocellular dense fibrous capsule that becomes impermeable or hypopermeable to many compounds. Porous substrates and angiogenic growth factors can stimulate formation of microvessels, which to some extent can maintain analyte delivery to implanted sensors. However, stimulation by vascular endothelial growth factor alone may lead to formation of leaky, thin-walled, immature vessels. Other growth factors are most probably needed to act upon these immature structures to create more robust vessels. During implantation of foreign bodies, the foreign-body response is difficult to overcome, and thousands of biomaterials have been tested. Biomimicry (i.e., creating membranes whose chemical structure mimics natural cellular compounds) may diminish the response, but as of this writing, it has not been possible to create a stealth material that circumvents the ability of the mammalian surveillance systems to distinguish foreign from self. PMID:19885259

Antibiofilm and Anti-Infection of a Marine Bacterial Exopolysaccharide Against Pseudomonas aeruginosa

PubMed Central

Wu, Shimei; Liu, Ge; Jin, Weihua; Xiu, Pengyuan; Sun, Chaomin

2016-01-01

Pseudomonas aeruginosa is a well-known pathogenic bacterium that forms biofilms and produces virulence factors, thus leading to major problems in many fields, such as clinical infection, food contamination, and marine biofouling. In this study, we report the purification and characterization of an exopolysaccharide EPS273 from the culture supernatant of marine bacterium P. stutzeri 273. The exopolysaccharide EPS273 not only effectively inhibits biofilm formation but also disperses preformed biofilm of P. aeruginosa PAO1. High performance liquid chromatography traces of the hydrolyzed polysaccharides shows that EPS273 primarily consists of glucosamine, rhamnose, glucose and mannose. Further investigation demonstrates that EPS273 reduces the production of the virulence factors pyocyanin, exoprotease, and rhamnolipid, and the virulence of P. aeruginosa PAO1 to human lung cells A549 and zebrafish embryos is also obviously attenuated by EPS273. In addition, EPS273 also greatly reduces the production of hydrogen peroxide (H2O2) and extracellular DNA (eDNA), which are important factors for biofilm formation. Furthermore, EPS273 exhibits strong antioxidant potential by quenching hydroxyl and superoxide anion radicals. Notably, the antibiofouling activity of EPS273 is observed in the marine environment up to 2 weeks according to the amounts of bacteria and diatoms in the glass slides submerged in the ocean. Taken together, the properties of EPS273 indicate that it has a promising prospect in combating bacterial biofilm-associated infection, food-processing contamination and marine biofouling. PMID:26903981

Zwitterionic modification of polyurethane membranes for enhancing the anti-fouling property.

PubMed

Liu, Peiming; Huang, Tao; Liu, Pingsheng; Shi, Shufeng; Chen, Qiang; Li, Li; Shen, Jian

2016-10-15

Polyurethane (PU) is a biopolymer that has been commonly used for biomedical applications. However, the biofouling phenomenon on the hydrophobic PU surface is one of the crucial issues that embarrassing its applications. Here, we report a facile & efficient approach to improve the anti-biofouling ability of the PU substrates. Active residues were firstly generated on the PU surface by using the low temperature air-plasma treatment, promoting the immobilization of the atom transfer radical polymerization (ATRP) initiators on the surface. Then, three types of zwitterionic polymer brushes, as well as PEG brushes, have been fabricated on the PU substrates through surface-initiated ATRP (SI-ATRP). Robust surface characterizations that capable of revealing the surface chemistry (including X-ray photoelectron spectroscopy (XPS) and wettability tests), and antifouling evaluations of the PU substrates (protein adsorption, platelet adhesion, and cell adhesion measurements) were performed. Results showed that three types of zwitterionic brushes have been successful grafted on the PU surface, respectively. And the three types of zwitterionic brushes, in general, significantly inhibited the protein adsorption, the platelet adhesion, and the cell adhesion on the PU surface, endowing a significantly improved anti-fouling ability to the PU substrates. Furthermore, we found that this facial zwitterionic surface modification did not compromise the mechanical property of the PU substrates. This strategy could be easily exploited to PU-based biomaterials to improve their performance in many applications. Copyright © 2016 Elsevier Inc. All rights reserved.

OTEC biofouling, corrosion, and materials study from a moored platform at Punta Tuna, Puerto Rico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasscer, D.S.; Tosteson, T.R.; Morgan, T.O.

1981-08-01

During the 404 days between 29 January 1980 and 10 March 1981 the Center conducted an uninterrupted biofouling test at Punta Tuna, Puerto Rico, of periodically cleaned, OTEC evaporator tubes. The fouling resistance (R/sub f), total surface carbon and nitrogen content, ATP, and the wet film thickness (WFT) were determined throughout the test. Visual observations of the fouling film were made by light sectioning and scanning microscopy, and at the end of the test, a study was made of the macrofouling of the flow system. The results of thest tests indicate that a base layer of bacteria and exudated polysaccharidesmore » enhance microbial adhesion and thereby create an environment conducive to rapid film growth. Fouling rates (dR/sub f//dt) for aluminum were generally higher than for titanium but they were linear for both materials and did not exceed 0.3(10/sup -4/)ft/sup 2/-h-/sup 0/F/Btu-day for either material during the 13-month study. Excellent correlation was found to exist between R/sub f/ and WFT which supports the hypothesis that it is the stagnant film of water entrapped by bacteria which is largely responsible for the insulating properties of the biofilm. The macrofouling study identified 61 species of benthic invertebrates representing ten phyla growing in those parts of the flow system, where flow was less than 3 fps but no macrofouling where the flow velocity significantly exceeded 3 fps.« less

OTEC biofouling, corrosion, and materials study from a moored platform at Punta Tuna, Puerto Rico - 1. - fouling resistance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasscer, D.S.; Morgan, T.O.; Rivera, C.

1981-01-01

A biofouling test of 404 days was conducted on evaporator tubes of an ocean thermal energy conversion plant of the Center for Energy and Environmental Research. The fouling resistance (R/sub f/), total surface carbon and nitrogen content, ATP, and the wet film thickness (WFT) were determined throughout the test. Visual observations of the fouling film were made by light sectioning and scanning microscopy, and at the end of the test, a study was made of the macrofouling of the flow system. The results of these tests indicate that a base layer of bacteria and exudated polysaccharides enhance microbial adhesion andmore » thereby create an environment conducive to rapid film growth. Fouling rates (dR/sub f//dt) for aluminum were generally higher than for titanium but they were linear for both materials and did not exceed 0.3(10/sup -4/)ft/sup 2/-hr-/degree/F/Btu-day for either material during the 13-month study. Excellent correlation was found to exist between R/sub f/ and WFT, which supports the hypothesis that it is the stagnant film of water entrapped by bacteria which is largely responsible for the insulating properties of the biofilm. The macrofouling study identified 61 species of benthic invertebrates representing ten phyla growing in those parts of the flow system, where flow was less than 3 fps but no macrofouling where the flow velocity significantly exceeded 3 fps. 24 refs.« less

Composition and Variability of Biofouling Organisms in Seawater Reverse Osmosis Desalination Plants ▿ †

PubMed Central

Zhang, Minglu; Jiang, Sunny; Tanuwidjaja, Dian; Voutchkov, Nikolay; Hoek, Eric M. V.; Cai, Baoli

2011-01-01

Seawater reverse osmosis (SWRO) membrane biofouling remains a common challenge in the desalination industry, but the marine bacterial community that causes membrane fouling is poorly understood. Microbial communities at different stages of treatment processes (intake, cartridge filtration, and SWRO) of a desalination pilot plant were examined by both culture-based and culture-independent approaches. Bacterial isolates were identified to match the genera Shewanella, Alteromonas, Vibrio, and Cellulophaga based on 16S rRNA gene sequencing analysis. The 16S rRNA gene clone library of the SWRO membrane biofilm showed that a filamentous bacterium, Leucothrix mucor, which belongs to the gammaproteobacteria, accounted for nearly 30% of the clone library, while the rest of the microorganisms (61.2% of the total clones) were related to the alphaproteobacteria. 16S rRNA gene terminal restriction fragment length polymorphism (T-RFLP) analysis indicated that bacteria colonizing the SWRO membrane represented a subportion of microbes in the source seawater; however, they were quite different from those colonizing the cartridge filter. The examination of five SWRO membranes from desalination plants located in different parts of the world showed that although the bacterial communities from the membranes were not identical to each other, some dominant bacteria were commonly observed. In contrast, bacterial communities in source seawater were significantly different based on location and season. Microbial profiles from 14 cartridge filters collected from different plants also revealed spatial trends. PMID:21551282

Biocontrol of fouling pests: Effect of diversity, identity and density of control agents.

PubMed

Atalah, Javier; Newcombe, Emma M; Zaiko, Anastasija

2016-04-01

Augmentative biocontrol, using native natural enemies, has been suggested as a promising tool to control marine biofouling pests on artificial structures. However, there are still important knowledge gaps to be addressed before biocontrol can be considered as a management tool. In a field experiment on floating marine structures we examined intra- and interspecific consumer interactions among biocontrol agents on different surface orientations. We tested the effect of identity, density and diversity of three invertebrates (the 11-arm seastar Coscinasterias muricata, the sea urchin Evechinus chloroticus and the gastropod Cook's turban Cookia sulcata) to reduce established biofouling and to prevent fouling growth on defouled surfaces. High densities of biocontrol agents were not more effective at fouling control (cover and biomass) than low densities. Nor did multi-species treatments function more effectively than mono-specific ones. However, biocontrol agent identity was important, with the 11-arm seastar and Cook's turban being the most effective at fouling reduction and prevention, respectively. Surface orientation had a strong effect on the effectiveness of control agents, with the best results obtained on vertical compared to diagonal and underside surfaces. This study confirmed the potential of biocontrol as a management tool for marine pest, indicating that identity is more important than richness and density of control agents. It also highlighted the limitations of this approach on diagonal and underside surfaces, where control agents have limited retention ability. Copyright © 2016 Elsevier Ltd. All rights reserved.

Electrochemical Approach for Effective Antifouling and Antimicrobial Surfaces.

PubMed

Gaw, Sheng Long; Sarkar, Sujoy; Nir, Sivan; Schnell, Yafit; Mandler, Daniel; Xu, Zhichuan J; Lee, Pooi See; Reches, Meital

2017-08-09

Biofouling, the adsorption of organisms to a surface, is a major problem today in many areas of our lives. This includes: (i) health, as biofouling on medical device leads to hospital-acquired infections, (ii) water, since the accumulation of organisms on membranes and pipes in desalination systems harms the function of the system, and (iii) energy, due to the heavy load of the organic layer that accumulates on marine vessels and causes a larger consumption of fuel. This paper presents an effective electrochemical approach for generating antifouling and antimicrobial surfaces. Distinct from previously reported antifouling or antimicrobial electrochemical studies, we demonstrate the formation of a hydrogen gas bubble layer through the application of a low-voltage square-waveform pulses to the conductive surface. This electrochemically generated gas bubble layer serves as a separation barrier between the surroundings and the target surface where the adhesion of bacteria can be deterred. Our results indicate that this barrier could effectively reduce the adsorption of bacteria to the surface by 99.5%. We propose that the antimicrobial mechanism correlates with the fundamental of hydrogen evolution reaction (HER). HER leads to an arid environment that does not allow the existence of live bacteria. In addition, we show that this drought condition kills the preadhered bacteria on the surface due to water stress. This work serves as the basis for the exploration of future self-sustainable antifouling techniques such as incorporating it with photocatalytic and photoelectrochemical reactions.

Biofouling on buoyant marine plastics: An experimental study into the effect of size on surface longevity.

PubMed

Fazey, Francesca M C; Ryan, Peter G

2016-03-01

Recent estimates suggest that roughly 100 times more plastic litter enters the sea than is found floating at the sea surface, despite the buoyancy and durability of many plastic polymers. Biofouling by marine biota is one possible mechanism responsible for this discrepancy. Microplastics (<5 mm in diameter) are more scarce than larger size classes, which makes sense because fouling is a function of surface area whereas buoyancy is a function of volume; the smaller an object, the greater its relative surface area. We tested whether plastic items with high surface area to volume ratios sank more rapidly by submerging 15 different sizes of polyethylene samples in False Bay, South Africa, for 12 weeks to determine the time required for samples to sink. All samples became sufficiently fouled to sink within the study period, but small samples lost buoyancy much faster than larger ones. There was a direct relationship between sample volume (buoyancy) and the time to attain a 50% probability of sinking, which ranged from 17 to 66 days of exposure. Our results provide the first estimates of the longevity of different sizes of plastic debris at the ocean surface. Further research is required to determine how fouling rates differ on free floating debris in different regions and in different types of marine environments. Such estimates could be used to improve model predictions of the distribution and abundance of floating plastic debris globally. Copyright © 2016 Elsevier Ltd. All rights reserved.

Final Technical Report: Development of Post-Installation Monitoring Capabilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polagye, Brian

2014-03-31

The development of approaches to harness marine and hydrokinetic energy at large-scale is predicated on the compatibility of these generation technologies with the marine environment. At present, aspects of this compatibility are uncertain. Demonstration projects provide an opportunity to address these uncertainties in a way that moves the entire industry forward. However, the monitoring capabilities to realize these advances are often under-developed in comparison to the marine and hydrokinetic energy technologies being studied. Public Utility District No. 1 of Snohomish County has proposed to deploy two 6-meter diameter tidal turbines manufactured by OpenHydro in northern Admiralty Inlet, Puget Sound, Washington.more » The goal of this deployment is to provide information about the environmental, technical, and economic performance of such turbines that can advance the development of larger-scale tidal energy projects, both in the United States and internationally. The objective of this particular project was to develop environmental monitoring plans in collaboration with resource agencies, while simultaneously advancing the capabilities of monitoring technologies to the point that they could be realistically implemented as part of these plans. In this, the District was joined by researchers at the Northwest National Marine Renewable Energy Center at the University of Washington, Sea Mammal Research Unit, LLC, H.T. Harvey & Associates, and Pacific Northwest National Laboratory. Over a two year period, the project team successfully developed four environmental monitoring and mitigation plans that were adopted as a condition of the operating license for the demonstration project that issued by the Federal Energy Regulatory Commission in March 2014. These plans address nearturbine interactions with marine animals, the sound produced by the turbines, marine mammal behavioral changes associated with the turbines, and changes to benthic habitat associated with colonization of the subsea base support structure. In support of these plans, the project team developed and field tested a strobe-illuminated stereooptical camera system suitable for studying near-turbine interactions with marine animals. The camera system underwent short-term field testing at the proposed turbine deployment site and a multi-month endurance test in shallower water to evaluate the effectiveness of biofouling mitigation measures for the optical ports on camera and strobe pressure housings. These tests demonstrated that the camera system is likely to meet the objectives of the near-turbine monitoring plan and operate, without maintenance, for periods of at least three months. The project team also advanced monitoring capabilities related to passive acoustic monitoring of marine mammals and monitoring of tidal currents. These capabilities will be integrated in a recoverable monitoring package that has a single interface point with the OpenHydro turbines, connects to shore power and data via a wet-mate connector, and can be recovered to the surface for maintenance and reconfiguration independent of the turbine. A logical next step would be to integrate these instruments within the package, such that one instrument can trigger the operation of another.« less

40 CFR 122.48 - Requirements for recording and reporting of monitoring results (applicable to State programs, see...

Code of Federal Regulations, 2013 CFR

2013-07-01

... representative of the monitored activity including, when appropriate, continuous monitoring; (c) Applicable... reporting of monitoring results (applicable to State programs, see § 123.25). 122.48 Section 122.48... recording and reporting of monitoring results (applicable to State programs, see § 123.25). All permits...

40 CFR 122.48 - Requirements for recording and reporting of monitoring results (applicable to State programs, see...

Code of Federal Regulations, 2014 CFR

2014-07-01

... representative of the monitored activity including, when appropriate, continuous monitoring; (c) Applicable... reporting of monitoring results (applicable to State programs, see § 123.25). 122.48 Section 122.48... recording and reporting of monitoring results (applicable to State programs, see § 123.25). All permits...

40 CFR 122.48 - Requirements for recording and reporting of monitoring results (applicable to State programs, see...

Code of Federal Regulations, 2012 CFR

2012-07-01

... representative of the monitored activity including, when appropriate, continuous monitoring; (c) Applicable... reporting of monitoring results (applicable to State programs, see § 123.25). 122.48 Section 122.48... recording and reporting of monitoring results (applicable to State programs, see § 123.25). All permits...

40 CFR 122.48 - Requirements for recording and reporting of monitoring results (applicable to State programs, see...

Code of Federal Regulations, 2010 CFR

2010-07-01

... representative of the monitored activity including, when appropriate, continuous monitoring; (c) Applicable... reporting of monitoring results (applicable to State programs, see § 123.25). 122.48 Section 122.48... recording and reporting of monitoring results (applicable to State programs, see § 123.25). All permits...

40 CFR 122.48 - Requirements for recording and reporting of monitoring results (applicable to State programs, see...

Code of Federal Regulations, 2011 CFR

2011-07-01

... representative of the monitored activity including, when appropriate, continuous monitoring; (c) Applicable... reporting of monitoring results (applicable to State programs, see § 123.25). 122.48 Section 122.48... recording and reporting of monitoring results (applicable to State programs, see § 123.25). All permits...

A comparison of the temporally integrated monitoring of ecosystems and Adirondack Long Term-Monitoring programs in the Adirondack Mountain region of New Yrok

EPA Science Inventory

This paper compares lake chemistry in the Adirondack region of New York measured by the Temporally Integrated Monitoring of Ecosystems (TIME) and Adirondack Long-Term Monitoring (ALTM) programs by examining the data from six lakes common to both programs. Both programs were initi...

Cost considerations for long-term ecological monitoring

USGS Publications Warehouse

Caughlan, L.; Oakley, K.L.

2001-01-01

For an ecological monitoring program to be successful over the long-term, the perceived benefits of the information must justify the cost. Financial limitations will always restrict the scope of a monitoring program, hence the program's focus must be carefully prioritized. Clearly identifying the costs and benefits of a program will assist in this prioritization process, but this is easier said than done. Frequently, the true costs of monitoring are not recognized and are, therefore, underestimated. Benefits are rarely evaluated, because they are difficult to quantify. The intent of this review is to assist the designers and managers of long-term ecological monitoring programs by providing a general framework for building and operating a cost-effective program. Previous considerations of monitoring costs have focused on sampling design optimization. We present cost considerations of monitoring in a broader context. We explore monitoring costs, including both budgetary costs--what dollars are spent on--and economic costs, which include opportunity costs. Often, the largest portion of a monitoring program budget is spent on data collection, and other, critical aspects of the program, such as scientific oversight, training, data management, quality assurance, and reporting, are neglected. Recognizing and budgeting for all program costs is therefore a key factor in a program's longevity. The close relationship between statistical issues and cost is discussed, highlighting the importance of sampling design, replication and power, and comparing the costs of alternative designs through pilot studies and simulation modeling. A monitoring program development process that includes explicit checkpoints for considering costs is presented. The first checkpoint occur during the setting of objectives and during sampling design optimization. The last checkpoint occurs once the basic shape of the program is known, and the costs and benefits, or alternatively the cost-effectiveness, of each program element can be evaluated. Moving into the implementation phase without careful evaluation of costs and benefits is risky because if costs are later found to exceed benefits, the program will fail. The costs of development, which can be quite high, will have been largely wasted. Realistic expectations of costs and benefits will help ensure that monitoring programs survive the early, turbulent stages of development and the challenges posed by fluctuating budgets during implementation.

7 CFR 246.19 - Management evaluation and monitoring reviews.

Code of Federal Regulations, 2014 CFR

2014-01-01

... SERVICE, DEPARTMENT OF AGRICULTURE CHILD NUTRITION PROGRAMS SPECIAL SUPPLEMENTAL NUTRITION PROGRAM FOR WOMEN, INFANTS AND CHILDREN Monitoring and Review § 246.19 Management evaluation and monitoring reviews... reports, the development of corrective action plans to resolve Program deficiencies, the monitoring of the...

7 CFR 246.19 - Management evaluation and monitoring reviews.

Code of Federal Regulations, 2012 CFR

2012-01-01

... SERVICE, DEPARTMENT OF AGRICULTURE CHILD NUTRITION PROGRAMS SPECIAL SUPPLEMENTAL NUTRITION PROGRAM FOR WOMEN, INFANTS AND CHILDREN Monitoring and Review § 246.19 Management evaluation and monitoring reviews... reports, the development of corrective action plans to resolve Program deficiencies, the monitoring of the...

7 CFR 246.19 - Management evaluation and monitoring reviews.

Code of Federal Regulations, 2013 CFR

2013-01-01

... SERVICE, DEPARTMENT OF AGRICULTURE CHILD NUTRITION PROGRAMS SPECIAL SUPPLEMENTAL NUTRITION PROGRAM FOR WOMEN, INFANTS AND CHILDREN Monitoring and Review § 246.19 Management evaluation and monitoring reviews... reports, the development of corrective action plans to resolve Program deficiencies, the monitoring of the...

7 CFR 246.19 - Management evaluation and monitoring reviews.

Code of Federal Regulations, 2010 CFR

2010-01-01

... SERVICE, DEPARTMENT OF AGRICULTURE CHILD NUTRITION PROGRAMS SPECIAL SUPPLEMENTAL NUTRITION PROGRAM FOR WOMEN, INFANTS AND CHILDREN Monitoring and Review § 246.19 Management evaluation and monitoring reviews... reports, the development of corrective action plans to resolve Program deficiencies, the monitoring of the...

7 CFR 246.19 - Management evaluation and monitoring reviews.

Code of Federal Regulations, 2011 CFR

2011-01-01

... SERVICE, DEPARTMENT OF AGRICULTURE CHILD NUTRITION PROGRAMS SPECIAL SUPPLEMENTAL NUTRITION PROGRAM FOR WOMEN, INFANTS AND CHILDREN Monitoring and Review § 246.19 Management evaluation and monitoring reviews... reports, the development of corrective action plans to resolve Program deficiencies, the monitoring of the...

45 CFR 2543.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2014 CFR

2014-10-01

... OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Property Standards § 2543.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients shall monitor subawards to...

15 CFR 14.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2011 CFR

2011-01-01

...-PROFIT, AND COMMERCIAL ORGANIZATIONS Post-Award Requirements Reports and Records § 14.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients shall monitor subawards to...

14 CFR 1260.151 - Monitoring and reporting program performance.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Records § 1260.151 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subcontract, function or activity supported by the award. Recipients shall monitor subcontracts to ensure subcontractors have met the audit requirements as delineated...

14 CFR 1260.151 - Monitoring and reporting program performance.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Records § 1260.151 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subcontract, function or activity supported by the award. Recipients shall monitor subcontracts to ensure subcontractors have met the audit requirements as delineated...

15 CFR 14.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2013 CFR

2013-01-01

...-PROFIT, AND COMMERCIAL ORGANIZATIONS Post-Award Requirements Reports and Records § 14.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients shall monitor subawards to...

45 CFR 2543.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2013 CFR

2013-10-01

... OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Property Standards § 2543.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients shall monitor subawards to...

14 CFR 1260.151 - Monitoring and reporting program performance.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Records § 1260.151 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subcontract, function or activity supported by the award. Recipients shall monitor subcontracts to ensure subcontractors have met the audit requirements as delineated...

45 CFR 2543.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2012 CFR

2012-10-01

... OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Property Standards § 2543.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients shall monitor subawards to...

45 CFR 2543.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2011 CFR

2011-10-01

... OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Property Standards § 2543.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients shall monitor subawards to...

15 CFR 14.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2014 CFR

2014-01-01

...-PROFIT, AND COMMERCIAL ORGANIZATIONS Post-Award Requirements Reports and Records § 14.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients shall monitor subawards to...

15 CFR 14.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2012 CFR

2012-01-01

...-PROFIT, AND COMMERCIAL ORGANIZATIONS Post-Award Requirements Reports and Records § 14.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients shall monitor subawards to...

Review of present groundwater monitoring programs at the Nevada Test Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hershey, R.L.; Gillespie, D.

1993-09-01

Groundwater monitoring at the Nevada Test Site (NTS) is conducted to detect the presence of radionuclides produced by underground nuclear testing and to verify the quality and safety of groundwater supplies as required by the State of Nevada and federal regulations, and by U.S. Department of Energy (DOE) Orders. Groundwater is monitored at water-supply wells and at other boreholes and wells not specifically designed or located for traditional groundwater monitoring objectives. Different groundwater monitoring programs at the NTS are conducted by several DOE Nevada Operations Office (DOE/NV) contractors. Presently, these individual groundwater monitoring programs have not been assessed or administeredmore » under a comprehensive planning approach. Redundancy exists among the programs in both the sampling locations and the constituents analyzed. Also, sampling for certain radionuclides is conducted more frequently than required. The purpose of this report is to review the existing NTS groundwater monitoring programs and make recommendations for modifying the programs so a coordinated, streamlined, and comprehensive monitoring effort may be achieved by DOE/NV. This review will be accomplished in several steps. These include: summarizing the present knowledge of the hydrogeology of the NTS and the potential radionuclide source areas for groundwater contamination; reviewing the existing groundwater monitoring programs at the NTS; examining the rationale for monitoring and the constituents analyzed; reviewing the analytical methods used to quantify tritium activity; discussing monitoring network design criteria; and synthesizing the information presented and making recommendations based on the synthesis. This scope of work was requested by the DOE/NV Hydrologic Resources Management Program (HRMP) and satisfies the 1993 (fiscal year) HRMP Groundwater Monitoring Program Review task.« less

Inter-observer agreement of a multi-parameter campsite monitoring program on the Dixie National Forest, Utah

Treesearch

Nicholas J. Glidden; Martha E. Lee

2007-01-01

Precision is crucial to campsite monitoring programs. Yet, little empirical research has ever been published on the level of precision of this type of monitoring programs. The purpose of this study was to evaluate the level of agreement between observers of campsite impacts using a multi-parameter campsite monitoring program. Thirteen trained observers assessed 16...

An overview of a landbird monitoring program at Tortuguero, on the Caribbean coast of Costa Rica

Treesearch

C. John Ralph; Margaret J. Widdowson; Robert I. Frey; Pablo A. Herrera; Brian P. O' Donnell

2005-01-01

Since 1994, the Tortuguero Integrated Bird Monitoring Program has been monitoring birds in a coastal lowland rain forest of northeast Costa Rica. The Program has combined the use of area searches, constanteffort mist netting, and migration counts into a longterm landbird monitoring and training program following the recommendations of the Partners In Flight &ndash...

28 CFR 70.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., HOSPITALS AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Reports and Records § 70.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients must monitor subawards...

29 CFR 95.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-Award Requirements Reports and Records § 95.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients shall monitor subawards to ensure subrecipients have met the audit...

29 CFR 95.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-Award Requirements Reports and Records § 95.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients shall monitor subawards to ensure subrecipients have met the audit...

29 CFR 95.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-Award Requirements Reports and Records § 95.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients shall monitor subawards to ensure subrecipients have met the audit...

22 CFR 226.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2014 CFR

2014-04-01

... ASSISTANCE AWARDS TO U.S. NON-GOVERNMENTAL ORGANIZATIONS Post-award Requirements Reports and Records § 226.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients shall monitor...

22 CFR 226.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2012 CFR

2012-04-01

... ASSISTANCE AWARDS TO U.S. NON-GOVERNMENTAL ORGANIZATIONS Post-award Requirements Reports and Records § 226.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients shall monitor...

29 CFR 95.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2014 CFR

2014-07-01

...-Award Requirements Reports and Records § 95.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients shall monitor subawards to ensure subrecipients have met the audit...

22 CFR 226.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2013 CFR

2013-04-01

... ASSISTANCE AWARDS TO U.S. NON-GOVERNMENTAL ORGANIZATIONS Post-award Requirements Reports and Records § 226.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients shall monitor...

28 CFR 70.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., HOSPITALS AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Reports and Records § 70.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients must monitor subawards...

28 CFR 70.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., HOSPITALS AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Reports and Records § 70.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients must monitor subawards...

28 CFR 70.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., HOSPITALS AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Reports and Records § 70.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients must monitor subawards...

14 CFR § 1260.151 - Monitoring and reporting program performance.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Records § 1260.151 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subcontract, function or activity supported by the award. Recipients shall monitor subcontracts to ensure subcontractors have met the audit requirements as delineated...

22 CFR 226.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2011 CFR

2011-04-01

... ASSISTANCE AWARDS TO U.S. NON-GOVERNMENTAL ORGANIZATIONS Post-award Requirements Reports and Records § 226.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award. Recipients shall monitor...

Central Alaska Network vital signs monitoring plan

USGS Publications Warehouse

MacCluskie, Margaret C.; Oakley, Karen L.; McDonald, Trent; Wilder, Doug

2005-01-01

Denali National Park and Preserve, Wrangell-St. Elias National Park and Preserve, and Yukon-Charley Rivers National Preserve have been organized into the Central Alaska Network (CAKN) for the purposes of carrying out ecological monitoring activities under the National Park Services’ Vital Signs Monitoring program. The Phase III Report is the initial draft of the Vital Signs Monitoring Plan for the Central Alaska Network. It includes updated material from the Phase I and II documents. This report, and draft protocols for 11 of the network’s Vital Signs, were peer reviewed early in 2005. Review comments were incorporated into the document bringing the network to the final stage of having a Vital Signs Monitoring Plan. Implementation of the program will formally begin in FY 2006. The broad goals of the CAKN monitoring program are to: (1) better understand the dynamic nature and condition of park ecosystems; and (2) provide reference points for comparisons with other, altered environments. The focus of the CAKN program will be to monitor ecosystems in order to detect change in ecological components and in the relationships among the components. Water quality monitoring is fully integrated within the CAKN monitoring program. A monitoring program for lentic (non-moving water) has been determined, and the program for lotic systems (moving water) is under development.

24 CFR 266.520 - Program monitoring and compliance.

Code of Federal Regulations, 2010 CFR

2010-04-01

... AUTHORITIES HOUSING FINANCE AGENCY RISK-SHARING PROGRAM FOR INSURED AFFORDABLE MULTIFAMILY PROJECT LOANS Project Management and Servicing § 266.520 Program monitoring and compliance. HUD will monitor the...

24 CFR 266.520 - Program monitoring and compliance.

Code of Federal Regulations, 2012 CFR

2012-04-01

... AUTHORITIES HOUSING FINANCE AGENCY RISK-SHARING PROGRAM FOR INSURED AFFORDABLE MULTIFAMILY PROJECT LOANS Project Management and Servicing § 266.520 Program monitoring and compliance. HUD will monitor the...

24 CFR 266.520 - Program monitoring and compliance.

Code of Federal Regulations, 2011 CFR

2011-04-01

... AUTHORITIES HOUSING FINANCE AGENCY RISK-SHARING PROGRAM FOR INSURED AFFORDABLE MULTIFAMILY PROJECT LOANS Project Management and Servicing § 266.520 Program monitoring and compliance. HUD will monitor the...

24 CFR 266.520 - Program monitoring and compliance.

Code of Federal Regulations, 2013 CFR

2013-04-01

... AUTHORITIES HOUSING FINANCE AGENCY RISK-SHARING PROGRAM FOR INSURED AFFORDABLE MULTIFAMILY PROJECT LOANS Project Management and Servicing § 266.520 Program monitoring and compliance. HUD will monitor the...

24 CFR 266.520 - Program monitoring and compliance.

Code of Federal Regulations, 2014 CFR

2014-04-01

... AUTHORITIES HOUSING FINANCE AGENCY RISK-SHARING PROGRAM FOR INSURED AFFORDABLE MULTIFAMILY PROJECT LOANS Project Management and Servicing § 266.520 Program monitoring and compliance. HUD will monitor the...

Antifouling coatings via plasma polymerization and atom transfer radical polymerization on thin film composite membranes for reverse osmosis

NASA Astrophysics Data System (ADS)

Hirsch, Ulrike; Ruehl, Marco; Teuscher, Nico; Heilmann, Andreas

2018-04-01

A major drawback to otherwise highly efficient membrane-based desalination techniques like reverse osmosis (RO) is the susceptibility of the membranes to biofouling. In this work, a combination of plasma activation, plasma bromination and surface-initiated atom transfer radical polymerization (si-ATRP) of hydrophilic and zwitterionic monomers, namely hydroxyethyl methacrylate (HEMA), 2-methacryloyloxyethyl phosphorylcholine (MPC) and [2-(methacryloyloxy)ethyl]-dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA), was applied to generate non-specific, anti-adhesive coatings on thin film composite (TFC) membranes. The antifouling effect of the coatings was shown by short-time batch as well as long-time steady state cultivation experiments with the microorganism Pseudomonas fluorescens. It could be shown that plasma functionalization and polymerization is possible on delicate thin film composite membranes without restricting their filtration performance. All modified membranes showed an increased resistance towards the adhesion of Pseudomonas fluorescens. On average, the biofilm coverage was reduced by 51.4-12.6% (for HEMA, SBMA, and MPC), the highest reduction was monitored for MPC with a biofilm reduction by 85.4%. The hydrophilic coatings applied did not only suppress the adhesion of Pseudomonas fluorescens, but also significantly increase the permeate flux of the membranes relative to uncoated membranes. The stability of the coatings was however not ideal and will have to be improved for future commercial use.

Method for Localizing and Differentiating Bacteria within Biofilms Grown on Indium Tin Oxide: Spatial Distribution of Exoelectrogenic Bacteria within Intact ITO Biofilms via FISH

DTIC Science & Technology

2017-11-01

404938, “Microbe-surface Interactions in Biofouling and Corrosion” ERDC/CERL TR-17-42 ii Abstract With a limited supply of fossil fuel, there has been...TR-17-42 iv Figures and Tables Figures Figure 1. DFR system used to rapidly form biofilms on ITO-coated glass substrates; (a) bioreactor with ITO...There is a finite amount of fossil fuel remaining in the world, and at cur- rently predicted rates of consumption, it is estimated that strategic re

Biodegradation of natural reinforcing fillers for polymer composites

NASA Astrophysics Data System (ADS)

Mastalygina, E. E.; Pantyukhov, P. V.; Popov, A. A.

2018-05-01

Twelve different natural raw materials were selected as possible fillers for eco-friendly biocomposites. The target was to find the most biodegradable ones. Two mycological tests were held: in the aqueous and agar media. It was found that two tests showed different results. In aqueous media, the fillers with a high content of water-soluble and easy-hydrolysed compounds demostrated the most intensive biofouling. In agar media, the entire filler was exposed to biodigestion by fungi. Therefore, multi-compound fillers with a set of different macro- and microelements were more biodegradable than others.

Synergistic prevention of biofouling in seawater desalination by zwitterionic surfaces and low-level chlorination.

PubMed

Yang, Rong; Jang, Hongchul; Stocker, Roman; Gleason, Karen K

2014-03-19

Smooth, durable, ultrathin antifouling layers are deposited onto commercial reverse osmosis membranes without damaging them and they exhibit a fouling reduction. A new synergistic approach to antifouling, by coupling surface modification and drinking-water-level chlorination is enabled by the films' unique resistance against chlorine degradation. This approach substantially enhances longer-term fouling resistance compared with surface modification or chlorination alone, and can reduce freshwater production cost and its collateral toxicity to marine biota. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Advanced composite applications for sub-micron biologically derived microstructures

NASA Technical Reports Server (NTRS)

Schnur, J. M.; Price, R. R.; Schoen, P. E.; Bonanventura, Joseph; Kirkpatrick, Douglas

1991-01-01

A major thrust of advanced material development is in the area of self-assembled ultra-fine particulate based composites (micro-composites). The application of biologically derived, self-assembled microstructures to form advanced composite materials is discussed. Hollow 0.5 micron diameter cylindrical shaped microcylinders self-assemble from diacetylenic lipids. These microstructures have a multiplicity of potential applications in the material sciences. Exploratory development is proceeding in application areas such as controlled release for drug delivery, wound repair, and biofouling as well as composites for electronic and magnetic applications, and high power microwave cathodes.

The role of population monitoring in the management of North American waterfowl

USGS Publications Warehouse

Nichols, J.D.; Williams, B.K.; Johnson, F.A.

2000-01-01

Despite the effort and expense devoted to large-scale monitoring programs, few existing programs have been designed with specific objectives in mind and few permit strong inferences about the dynamics of monitored systems. The waterfowl population monitoring programs of the U.S. Fish and Wildlife Service, Canadian Wildlife Service and state and provincial agencies provide a nice example with respect to program objectives, design and implementation. The May Breeding Grounds Survey provides an estimate of system state (population size) that serves two primary purposes in the adaptive management process: identifying the appropriate time-specific management actions and updating the information state (model weights) by providing a basis for evaluating predictions of competing models. Other waterfowl monitoring programs (e.g., banding program, hunter questionnaire survey, parts collection survey, winter survey) provide estimates of vital rates (rates of survival, reproduction and movement) associated with system dynamics and variables associated with management objectives (e.g., harvest). The reliability of estimates resulting from monitoring programs depends strongly on whether considerations about spatial variation and detection probability have been adequately incorporated into program design and implementation. Certain waterfowl surveys again provide nice examples of monitoring programs that incorporate these considerations.

Ecological Monitoring and Compliance Program 2011 Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, D. J.; Anderson, D. C.; Hall, D. B.

The Ecological Monitoring and Compliance (EMAC) Program, funded through the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, monitors the ecosystem of the Nevada National Security Site and ensures compliance with laws and regulations pertaining to NNSS biota. This report summarizes the program's activities conducted by National Security Technologies, LLC, during calendar year 2011. Program activities included (a) biological surveys at proposed construction sites, (b) desert tortoise compliance, (c) ecosystem monitoring, (d) sensitive plant species monitoring, (e) sensitive and protected/regulated animal monitoring, (f) habitat restoration monitoring, and (g) monitoring of the Nonproliferation Test and Evaluation Complex. Duringmore » 2011, all applicable laws, regulations, and permit requirements were met, enabling EMAC to achieve its intended goals and objectives.« less

The future role of next-generation DNA sequencing and metagenetics in aquatic biology monitoring programs

EPA Science Inventory

The development of current biological monitoring and bioassessment programs was a drastic improvement over previous programs created for monitoring a limited number of specific chemical pollutants. Although these assessment programs are better designed to address the transient an...

34 CFR 303.501 - Supervision and monitoring of programs.

Code of Federal Regulations, 2011 CFR

2011-07-01

... supervision of programs and activities receiving assistance under this part; and (2) The monitoring of... 34 Education 2 2011-07-01 2010-07-01 true Supervision and monitoring of programs. 303.501 Section... INFANTS AND TODDLERS WITH DISABILITIES State Administration General § 303.501 Supervision and monitoring...

34 CFR 303.501 - Supervision and monitoring of programs.

Code of Federal Regulations, 2010 CFR

2010-07-01

... supervision of programs and activities receiving assistance under this part; and (2) The monitoring of... 34 Education 2 2010-07-01 2010-07-01 false Supervision and monitoring of programs. 303.501 Section... INFANTS AND TODDLERS WITH DISABILITIES State Administration General § 303.501 Supervision and monitoring...

A western state perspective on monitoring and managing neotropical migratory birds

Treesearch

Frank Howe

1993-01-01

Neotropical migratory bird monitoring programs can contribute greatly to a more holistic and proactive management approach for state agencies. It is, however, imperative that these monitoring programs be scientifically designed and clearly communicated to managers. Information from monitoring programs can be used to develop multiple-species habitat management...

10 CFR 26.406 - Fitness monitoring.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Fitness monitoring. 26.406 Section 26.406 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS FFD Program for Construction § 26.406 Fitness monitoring. (a...) Licensees and other entities shall implement a fitness monitoring program to deter substance abuse and...

10 CFR 26.406 - Fitness monitoring.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Fitness monitoring. 26.406 Section 26.406 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS FFD Program for Construction § 26.406 Fitness monitoring. (a...) Licensees and other entities shall implement a fitness monitoring program to deter substance abuse and...

10 CFR 26.406 - Fitness monitoring.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Fitness monitoring. 26.406 Section 26.406 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS FFD Program for Construction § 26.406 Fitness monitoring. (a...) Licensees and other entities shall implement a fitness monitoring program to deter substance abuse and...

10 CFR 26.406 - Fitness monitoring.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Fitness monitoring. 26.406 Section 26.406 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS FFD Program for Construction § 26.406 Fitness monitoring. (a...) Licensees and other entities shall implement a fitness monitoring program to deter substance abuse and...

10 CFR 26.406 - Fitness monitoring.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Fitness monitoring. 26.406 Section 26.406 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS FFD Program for Construction § 26.406 Fitness monitoring. (a...) Licensees and other entities shall implement a fitness monitoring program to deter substance abuse and...

Nonnative Fishes in the Upper Mississippi River System

USGS Publications Warehouse

Irons, Kevin S.; DeLain, Steven A.; Gittinger, Eric; Ickes, Brian S.; Kolar, Cindy S.; Ostendort, David; Ratcliff, Eric N.; Benson, Amy J.; Irons, Kevin S.

2009-01-01

The introduction, spread, and establishment of nonnative species is widely regarded as a leading threat to aquatic biodiversity and consequently is ranked among the most serious environmental problems facing the United States today. This report presents information on nonnative fish species observed by the Long Term Resource Monitoring Program on the Upper Mississippi River System a nexus of North American freshwater fish diversity for the Nation. The Long Term Resource Monitoring Program, as part of the U.S. Army Corps of Engineers' Environmental Management Plan, is the Nation's largest river monitoring program and stands as the primary source of standardized ecological information on the Upper Mississippi River System. The Long Term Resource Monitoring Program has been monitoring fish communities in six study areas on the Upper Mississippi River System since 1989. During this period, more than 3.5 million individual fish, consisting of 139 species, have been collected. Although fish monitoring activities of the Long Term Resource Monitoring Program focus principally on entire fish communities, data collected by the Program are useful for detecting and monitoring the establishment and spread of nonnative fish species within the Upper Mississippi River System Basin. Sixteen taxa of nonnative fishes, or hybrids thereof, have been observed by the Long Term Resource Monitoring Program since 1989, and several species are presently expanding their distribution and increasing in abundance. For example, in one of the six study areas monitored by the Long Term Resource Monitoring Program, the number of established nonnative species has increased from two to eight species in less than 10 years. Furthermore, contributions of those eight species can account for up to 60 percent of the total annual catch and greater than 80 percent of the observed biomass. These observations are critical because the Upper Mississippi River System stands as a nationally significant pathway for nonnative species expansion between the Mississippi River and the Great Lakes Basin. This report presents a synthesis of data on nonnative fish species observed during Long Term Resource Monitoring Program monitoring activities.

Estuarine monitoring programs in the Albemarle Sound study area, North Carolina

USGS Publications Warehouse

Moorman, Michelle; Kolb, Katharine R.; Supak, Stacy

2014-01-01

The purpose of this report is to identify major natural resource management issues for the region, provide information on current monitoring activities occurring within the Albemarle Sound study area, determine how the current monitoring network fits into the design of the NMN, and determine what additional monitoring data are needed to address these issues. In order to address these questions, a shapefile and data table were created to document monitoring and research programs in the Albemarle Sound study area with an emphasis on current monitoring programs within the region. This database was queried to determine monitoring gaps that existed in the Albemarle Sound by comparing current monitoring programs with the design indicated by the NMN. The report uses this information to provide recommendations on how monitoring could be improved in the Albemarle Sound study area.

Generic command interpreter for robot controllers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Werner, J.

1991-04-09

Generic command interpreter programs have been written for robot controllers at Sandia National Laboratories (SNL). Each interpreter program resides on a robot controller and interfaces the controller with a supervisory program on another (host) computer. We call these interpreter programs monitors because they wait, monitoring a communication line, for commands from the supervisory program. These monitors are designed to interface with the object-oriented software structure of the supervisory programs. The functions of the monitor programs are written in each robot controller's native language but reflect the object-oriented functions of the supervisory programs. These functions and other specifics of the monitormore » programs written for three different robots at SNL will be discussed. 4 refs., 4 figs.« less

Program Monitoring Practices for Teachers of the Deaf and Hard of Hearing in Early Intervention

ERIC Educational Resources Information Center

Thomas, Anne E.; Marvin, Christine A.

2016-01-01

Program monitoring is an important and necessary assessment practice within the field of early childhood deaf education. Effective program monitoring requires a focus on both the consistent implementation of intervention strategies (fidelity) and the assessment of children's ongoing progress in response to interventions (progress monitoring).…

NCCN Mountain Lakes Monitoring Strategy: Guidelines to Resolution

USGS Publications Warehouse

Hoffman, Robert L.; Huff, Mark H.

2008-01-01

The North Coast and Cascades Network (NCCN) Inventory and Monitoring Program provides funds to its Network Parks to plan and implement the goals and objectives of the National Park Services? (NPS) Inventory and Monitoring (I&M) Program. The primary purpose of the I&M program is to develop and implement a long-term monitoring program in each network. The purpose of this document is to describe the outcome of a meeting held to find solutions to obstacles inhibiting development of a unified core design and methodology for mountain lake monitoring.

Long-term fish monitoring in large rivers: Utility of “benchmarking” across basins

USGS Publications Warehouse

Ward, David L.; Casper, Andrew F.; Counihan, Timothy D.; Bayer, Jennifer M.; Waite, Ian R.; Kosovich, John J.; Chapman, Colin; Irwin, Elise R.; Sauer, Jennifer S.; Ickes, Brian; McKerrow, Alexa

2017-01-01

In business, benchmarking is a widely used practice of comparing your own business processes to those of other comparable companies and incorporating identified best practices to improve performance. Biologists and resource managers designing and conducting monitoring programs for fish in large river systems tend to focus on single river basins or segments of large rivers, missing opportunities to learn from those conducting fish monitoring in other rivers. We briefly examine five long-term fish monitoring programs in large rivers in the United States (Colorado, Columbia, Mississippi, Illinois, and Tallapoosa rivers) and identify opportunities for learning across programs by detailing best monitoring practices and why these practices were chosen. Although monitoring objectives, methods, and program maturity differ between each river system, examples from these five case studies illustrate the important role that long-term monitoring programs play in interpreting temporal and spatial shifts in fish populations for both established objectives and newly emerging questions. We suggest that deliberate efforts to develop a broader collaborative network through benchmarking will facilitate sharing of ideas and development of more effective monitoring programs.

1996 LMITCO environmental monitoring program report for the Idaho National Engineering and Environmental Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1997-09-01

This report describes the calendar year 1996 environmental surveillance and compliance monitoring activities of the Lockheed Martin Idaho Technologies Company Environmental Monitoring Program performed at the Idaho National Engineering and Environmental Laboratory (INEEL). Results of sampling performed by the Radiological Environmental Surveillance, Site Environmental Surveillance, Drinking Water, Effluent Monitoring, Storm Water Monitoring, Groundwater Monitoring, and Special Request Monitoring Programs are included in this report. The primary purposes of the surveillance and monitoring activities are to evaluate environmental conditions, to provide and interpret data, to verify compliance with applicable regulations or standards, and to ensure protection of human health and themore » environment. This report compares 1996 data with program-specific regulatory guidelines and past data to evaluate trends.« less

Ecological Monitoring and Compliance Program 2007 Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, Dennis; Anderson, David; Derek, Hall

2008-03-01

In accordance with U.S. Department of Energy (DOE) Order 450.1, 'Environmental Protection Program', the Office of the Assistant Manager for Environmental Management of the DOE, National Nuclear Security Administration Nevada Site Office (NNSA/NSO) requires ecological monitoring and biological compliance support for activities and programs conducted at the Nevada Test Site (NTS). National Security Technologies, LLC (NSTec), Ecological Services has implemented the Ecological Monitoring and Compliance (EMAC) Program to provide this support. EMAC is designed to ensure compliance with applicable laws and regulations, delineate and define NTS ecosystems, and provide ecological information that can be used to predict and evaluate themore » potential impacts of proposed projects and programs on those ecosystems. This report summarizes the EMAC activities conducted by NSTec during calendar year 2007. Monitoring tasks during 2007 included eight program areas: (a) biological surveys, (b) desert tortoise compliance, (c) ecosystem mapping and data management, (d) sensitive plant monitoring, (e) sensitive and protected/regulated animal monitoring, (f) habitat monitoring, (g) habitat restoration monitoring, and (h) biological monitoring at the Nonproliferation Test and Evaluation Complex (NPTEC). The following sections of this report describe work performed under these eight areas.« less

A novel and cost-effective monitoring approach for outcomes in an Australian biodiversity conservation incentive program.

PubMed

Lindenmayer, David B; Zammit, Charles; Attwood, Simon J; Burns, Emma; Shepherd, Claire L; Kay, Geoff; Wood, Jeff

2012-01-01

We report on the design and implementation of ecological monitoring for an Australian biodiversity conservation incentive scheme - the Environmental Stewardship Program. The Program uses competitive auctions to contract individual land managers for up to 15 years to conserve matters of National Environmental Significance (with an initial priority on nationally threatened ecological communities). The ecological monitoring was explicitly aligned with the Program's policy objective and desired outcomes and was applied to the Program's initial Project which targeted the critically endangered White Box-Yellow Box-Blakely's Red Gum Grassy Woodland and Derived Native Grassland ecological community in south eastern Australia. These woodlands have been reduced to <3% of their original extent and persist mostly as small remnants of variable condition on private farmland. We established monitoring sites on 153 farms located over 172,232 sq km. On each farm we established a monitoring site within the woodland patch funded for management and, wherever possible, a matched control site. The monitoring has entailed gathering data on vegetation condition, reptiles and birds. We also gathered data on the costs of experimental design, site establishment, field survey, and data analysis. The costs of monitoring are approximately 8.5% of the Program's investment in the first four years and hence are in broad accord with the general rule of thumb that 5-10% of a program's funding should be invested in monitoring. Once initial monitoring and site benchmarking are completed we propose to implement a novel rotating sampling approach that will maintain scientific integrity while achieving an annual cost-efficiency of up to 23%. We discuss useful lessons relevant to other monitoring programs where there is a need to provide managers with reliable early evidence of program effectiveness and to demonstrate opportunities for cost-efficiencies.

Design and operation of internal dosimetry programs

DOE Office of Scientific and Technical Information (OSTI.GOV)

LaBone, T.R.

1991-01-01

The proposed revision to USNRC 10 CFR 20 and the USDOE Order 5480.11 require intakes of radioactive material to be evaluated. Radiation dose limits are based on the sum of effective dose equivalent from intakes and the whole body dose from external sources. These significant changes in the regulations will require, at a minimum, a complete review of personnel monitoring programs to determine their adequacy. In this session we will review a systematic method of designing a routine personnel monitoring program that will comply with the requirements of the new regulations. Specific questions discussed are: (a) What are the goalsmore » and objectives of a routine personnel monitoring program (b) When is a routine personnel monitoring program required (c) What are the required capabilities of the routine personnel monitoring program (d) What should be done with the information generated in a personnel monitoring program Specific recommendations and interpretations are given in the session. 5 refs., 3 figs., 33 tabs.« less

1993 Annual Report: San Francisco estuary regional monitoring program for trace substances

USGS Publications Warehouse

Thompson, B.; Lacy, Jessica; Hardin, Dane; Grovhaug, Tom; Taberski, K.; Jassby, Alan D.; Cloern, James E.; Caffrey, J.; Cole, B.; Schoellhamer, David H.

1993-01-01

Summaries of other monitoring activities pertinent to regional monitoring are also included in the Report: a description of the Regional Board’s Bay Protection Studies, the Sacramento Coordinated Monitoring Program, and a wetlands monitoring plan are included.

Measurement of Near-Surface Salinity, Temperature and Directional Wave Spectra using a Novel Wave-Following, Lagrangian Surface Contact Buoy

NASA Astrophysics Data System (ADS)

Boyle, J. P.

2016-02-01

Results from a surface contact drifter buoy which measures near-surface conductivity ( 10 cm depth), sea state characteristics and near-surface water temperature ( 2 cm depth) are described. This light (< 750 gram), wave-following discus buoy platform has a hull diameter of 25 cm and a thickness of approximately 3 cm. The buoy is designed to allow for capsize events, but remains top up because it is ballasted for self-righting. It has a small above-surface profile and low windage, resulting in near-Lagrangian drift characteristics. It is autonomous, with low power requirements and solar panel battery recharging. Onboard sensors include an inductive toroidal conductivity probe for salinity measurement, a nine-degrees-of-freedom motion package for derivation of directional wave spectra and a thermocouple for water temperature measurement. Data retrieval for expendable, ocean-going operation uses an onboard Argos transmitter. Scientific results as well as data processing algorithms are presented from laboratory and field experiments which support qualification of buoy platform measurements. These include sensor calibration experiments, longer-term dock-side biofouling experiments during 2013-2014 and a series of short-duration ocean deployments in the Gulf Stream in 2014. In addition, a treatment method will be described which appears to minimize the effects of biofouling on the inductive conductivity probe when in coastal surface waters. Due to its low cost and ease of deployment, scores, perhaps hundreds of these novel instruments could be deployed from ships or aircraft during process studies or to provide surface validation for satellite-based measurements, particularly in high precipitation regions.

Influence of Electric Fields on Biofouling of Carbonaceous Electrodes.

PubMed

Pandit, Soumya; Shanbhag, Sneha; Mauter, Meagan; Oren, Yoram; Herzberg, Moshe

2017-09-05

Biofouling commonly occurs on carbonaceous capacitive deionization electrodes in the process of treating natural waters. Although previous work reported the effect of electric fields on bacterial mortality for a variety of medical and engineered applications, the effect of electrode surface properties and the magnitude and polarity of applied electric fields on biofilm development has not been comprehensively investigated. This paper studies the formation of a Pseudomonas aeruginosa biofilm on a Papyex graphite (PA) and a carbon aerogel (CA) in the presence and the absence of an electric field. The experiments were conducted using a two-electrode flow cell with a voltage window of ±0.9 V. The CA was less susceptible to biofilm formation compared to the PA due to its lower surface roughness, lower hydrophobicity, and significant antimicrobial properties. For both positive and negative applied potentials, we observed an inverse relationship between biofilm formation and the magnitude of the applied potential. The effect is particularly strong for the CA electrodes and may be a result of cumulative effects between material toxicity and the stress experienced by cells at high applied potentials. Under the applied potentials for both electrodes, high production of endogenous reactive oxygen species (ROS) was indicative of bacterial stress. For both electrodes, the elevated specific ROS activity was lowest for the open circuit potential condition, elevated when cathodically and anodically polarized, and highest for the ±0.9 V cases. These high applied potentials are believed to affect the redox potential across the cell membrane and disrupt redox homeostasis, thereby inhibiting bacterial growth.

Automated DNA extraction platforms offer solutions to challenges of assessing microbial biofouling in oil production facilities.

PubMed

Oldham, Athenia L; Drilling, Heather S; Stamps, Blake W; Stevenson, Bradley S; Duncan, Kathleen E

2012-11-20

The analysis of microbial assemblages in industrial, marine, and medical systems can inform decisions regarding quality control or mitigation. Modern molecular approaches to detect, characterize, and quantify microorganisms provide rapid and thorough measures unbiased by the need for cultivation. The requirement of timely extraction of high quality nucleic acids for molecular analysis is faced with specific challenges when used to study the influence of microorganisms on oil production. Production facilities are often ill equipped for nucleic acid extraction techniques, making the preservation and transportation of samples off-site a priority. As a potential solution, the possibility of extracting nucleic acids on-site using automated platforms was tested. The performance of two such platforms, the Fujifilm QuickGene-Mini80™ and Promega Maxwell®16 was compared to a widely used manual extraction kit, MOBIO PowerBiofilm™ DNA Isolation Kit, in terms of ease of operation, DNA quality, and microbial community composition. Three pipeline biofilm samples were chosen for these comparisons; two contained crude oil and corrosion products and the third transported seawater. Overall, the two more automated extraction platforms produced higher DNA yields than the manual approach. DNA quality was evaluated for amplification by quantitative PCR (qPCR) and end-point PCR to generate 454 pyrosequencing libraries for 16S rRNA microbial community analysis. Microbial community structure, as assessed by DGGE analysis and pyrosequencing, was comparable among the three extraction methods. Therefore, the use of automated extraction platforms should enhance the feasibility of rapidly evaluating microbial biofouling at remote locations or those with limited resources.

Automated DNA extraction platforms offer solutions to challenges of assessing microbial biofouling in oil production facilities

PubMed Central

2012-01-01

The analysis of microbial assemblages in industrial, marine, and medical systems can inform decisions regarding quality control or mitigation. Modern molecular approaches to detect, characterize, and quantify microorganisms provide rapid and thorough measures unbiased by the need for cultivation. The requirement of timely extraction of high quality nucleic acids for molecular analysis is faced with specific challenges when used to study the influence of microorganisms on oil production. Production facilities are often ill equipped for nucleic acid extraction techniques, making the preservation and transportation of samples off-site a priority. As a potential solution, the possibility of extracting nucleic acids on-site using automated platforms was tested. The performance of two such platforms, the Fujifilm QuickGene-Mini80™ and Promega Maxwell®16 was compared to a widely used manual extraction kit, MOBIO PowerBiofilm™ DNA Isolation Kit, in terms of ease of operation, DNA quality, and microbial community composition. Three pipeline biofilm samples were chosen for these comparisons; two contained crude oil and corrosion products and the third transported seawater. Overall, the two more automated extraction platforms produced higher DNA yields than the manual approach. DNA quality was evaluated for amplification by quantitative PCR (qPCR) and end-point PCR to generate 454 pyrosequencing libraries for 16S rRNA microbial community analysis. Microbial community structure, as assessed by DGGE analysis and pyrosequencing, was comparable among the three extraction methods. Therefore, the use of automated extraction platforms should enhance the feasibility of rapidly evaluating microbial biofouling at remote locations or those with limited resources. PMID:23168231

A sensitive label-free immunosensor for detection α-Fetoprotein in whole blood based on anticoagulating magnetic nanoparticles.

PubMed

Xu, Tingting; Chi, Bo; Wu, Fan; Ma, Shangshang; Zhan, Shuyue; Yi, Meihui; Xu, Hong; Mao, Chun

2017-09-15

Accurate values of tumor markers in blood play an especially important role in the diagnosis of illness. Here, based on the combination of three techniques include anticoagulant technology, nanotechnology and biosensing technology, a sensitive label-free immunosensor with anti-biofouling electrode for detection α-Fetoprotein (AFP) in whole blood was developed by anticoagulating magnetic nanoparticles. The obtained products of Fe 3 O 4 -ɛ-PL-Hep nanoparticles were characterized by fourier transform infrared (FT-IR) spectra, transmission electron microscopy (TEM), ζ-potential and vibrating sample magnetometry (VSM). Moreover, the blood compatibility of anticoagulating magnetic nanoparticles was characterized by in vitro coagulation tests, hemolysis assay and whole blood adhesion tests. Combining the anticoagulant property of heparin (Hep) and the good magnetism of Fe 3 O 4 , the Fe 3 O 4 -ɛ-PL-Hep nanoparticles could improve not only the anti-biofouling property of the electrode surface when they contact with whole blood, but also the stability and reproducibility of the proposed immunosensor. Thus, the prepared anticoagulating magnetic nanoparticles modified immunosensor for the detection of AFP showed excellent electrochemical properties with a wide concentration range from 0.1 to 100ng/mL and a low detection limit of 0.072ng/mL. Furthermore, five blood samples were assayed using the developed immunosensor. The results showed satisfactory accuracy with low relative errors. It indicated that our developed immunoassay was competitive and could be potentially used for the detection of whole blood samples directly. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of N-Acylhomoserine Lactones Produced by Bacteria Isolated from Industrial Cooling Water Systems.

PubMed

Okutsu, Noriya; Morohoshi, Tomohiro; Xie, Xiaonan; Kato, Norihiro; Ikeda, Tsukasa

2015-12-30

The cooling water systems are used to remove heat generated in the various industries. Biofouling of the cooling water systems causes blocking of condenser pipes and the heat exchanger tubes. In many Gram-negative bacteria, N-acylhomoserine lactone (AHL) are used as quorum-sensing signal molecule and associated with biofilm formation. To investigate the relationship between quorum sensing and biofouling in the cooling water system, we isolated a total of 192 bacterial strains from the five cooling water systems, and screened for AHL production. Seven isolates stimulated AHL-mediated purple pigment production in AHL reporter strain Chromobacterium violaceum CV026 or VIR07. Based on their 16S rRNA gene sequences, AHL-producing isolates were assigned to Aeromonas hydrophila, Lysobacter sp., Methylobacterium oryzae, and Bosea massiliensis. To the best of our knowledge, B. massiliensis and Lysobacter sp. have not been reported as AHL-producing species in the previous researches. AHLs extracted from the culture supernatants of B. massiliensis and Lysobacter sp. were identified by liquid chromatography-mass spectrometry. AHLs produced by B. massiliensis were assigned as N-hexanoyl-L-homoserine lactone (C6-HSL), N-(3-oxohexanoyl)-L-homoserine lactone (3-oxo-C6-HSL), and N-(3-oxooctanoyl)-L-homoserine lactone (3-oxo-C8-HSL). AHLs produced by Lysobacter sp. were assigned as N-decanoyl-L-homoserine lactone (C10-HSL) and N-(3-oxodecanoyl)-L-homoserine lactone (3-oxo-C10-HSL). This is the first report of identification of AHLs produced by B. massiliensis and Lysobacter sp. isolated from the cooling water system.

Cost considerations for long-term ecological monitoring

USGS Publications Warehouse

Caughlan, L.; Oakley, K.L.

2001-01-01

For an ecological monitoring program to be successful over the long-term, the perceived benefits of the information must justify the cost. Financial limitations will always restrict the scope of a monitoring program, hence the program’s focus must be carefully prioritized. Clearly identifying the costs and benefits of a program will assist in this prioritization process, but this is easier said than done. Frequently, the true costs of monitoring are not recognized and are, therefore, underestimated. Benefits are rarely evaluated, because they are difficult to quantify. The intent of this review is to assist the designers and managers of long-term ecological monitoring programs by providing a general framework for building and operating a cost-effective program. Previous considerations of monitoring costs have focused on sampling design optimization. We present cost considerations of monitoring in a broader context. We explore monitoring costs, including both budgetary costs, what dollars are spent on, and economic costs, which include opportunity costs. Often, the largest portion of a monitoring program budget is spent on data collection, and other, critical aspects of the program, such as scientific oversight, training, data management, quality assurance, and reporting, are neglected. Recognizing and budgeting for all program costs is therefore a key factor in a program’s longevity. The close relationship between statistical issues and cost is discussed, highlighting the importance of sampling design, replication and power, and comparing the costs of alternative designs through pilot studies and simulation modeling. A monitoring program development process that includes explicit checkpoints for considering costs is presented. The first checkpoint occurs during the setting of objectives and during sampling design optimization. The last checkpoint occurs once the basic shape of the program is known, and the costs and benefits, or alternatively the cost-effectiveness, of each program element can be evaluated. Moving into the implementation phase without careful evaluation of costs and benefits is risky because if costs are later found to exceed benefits, the program will fail. The costs of development, which can be quite high, will have been largely wasted. Realistic expectations of costs and benefits will help ensure that monitoring programs survive the early, turbulent stages of development and the challenges posed by fluctuating budgets during implementation.

A framework for evaluating and designing citizen science programs for natural resources monitoring.

PubMed

Chase, Sarah K; Levine, Arielle

2016-06-01

We present a framework of resource characteristics critical to the design and assessment of citizen science programs that monitor natural resources. To develop the framework we reviewed 52 citizen science programs that monitored a wide range of resources and provided insights into what resource characteristics are most conducive to developing citizen science programs and how resource characteristics may constrain the use or growth of these programs. We focused on 4 types of resource characteristics: biophysical and geographical, management and monitoring, public awareness and knowledge, and social and cultural characteristics. We applied the framework to 2 programs, the Tucson (U.S.A.) Bird Count and the Maui (U.S.A.) Great Whale Count. We found that resource characteristics such as accessibility, diverse institutional involvement in resource management, and social or cultural importance of the resource affected program endurance and success. However, the relative influence of each characteristic was in turn affected by goals of the citizen science programs. Although the goals of public engagement and education sometimes complimented the goal of collecting reliable data, in many cases trade-offs must be made between these 2 goals. Program goals and priorities ultimately dictate the design of citizen science programs, but for a program to endure and successfully meet its goals, program managers must consider the diverse ways that the nature of the resource being monitored influences public participation in monitoring. © 2016 Society for Conservation Biology.

Regional Environmental Monitoring and Assessment Program Data (REMAP)

EPA Pesticide Factsheets

The Regional Environmental Monitoring and Assessment Program (REMAP) was initiated to test the applicability of the Environmental Monitoring and Assessment Program (EMAP) approach to answer questions about ecological conditions at regional and local scales. Using EMAP's statistical design and indicator concepts, REMAP conducts projects at smaller geographic scales and in shorter time frames than the national EMAP program.

A plan for the North American Bat Monitoring Program (NABat)

Treesearch

Susan C. Loeb; Thomas J. Rodhouse; Laura E. Ellison; Cori L. Lausen; Jonathan D. Reichard; Kathryn M. Irvine; Thomas E. Ingersoll; Jeremy T.H. Coleman; Wayne E. Thogmartin; John R. Sauer; Charles M. Francis; Mylea L. Bayless; Thomas R. Stanley; Douglas H. Johnson

2015-01-01

The purpose of the North American Bat Monitoring Program (NABat) is to create a continent-wide program to monitor bats at local to rangewide scales that will provide reliable data to promote effective conservation decisionmaking and the long-term viability of bat populations across the continent. This is an international, multiagency program. Four approaches will be...

Program Monitoring: The Role of Leadership in Planning, Assessment, and Communication. REL 2014-034

ERIC Educational Resources Information Center

Malone, Nolan; Narayan, Krishna; Mark, Lauren; Miller, Kirsten; Kekahio, Wendy

2014-01-01

As educators are increasingly called on to use data to inform improvement initiatives (and are being held accountable for doing so), there is a corresponding need for program leaders to monitor progress. Program monitoring--the systematic and continual observation and recording of key program aspects--can provide leaders with realistic assessments…

Groundwater monitoring of hydraulic fracturing in California: Recommendations for permit-required monitoring

NASA Astrophysics Data System (ADS)

Esser, B. K.; Beller, H. R.; Carroll, S.; Cherry, J. A.; Jackson, R. B.; Jordan, P. D.; Madrid, V.; Morris, J.; Parker, B. L.; Stringfellow, W. T.; Varadharajan, C.; Vengosh, A.

2015-12-01

California recently passed legislation mandating dedicated groundwater quality monitoring for new well stimulation operations. The authors provided the State with expert advice on the design of such monitoring networks. Factors that must be considered in designing a new and unique groundwater monitoring program include: Program design: The design of a monitoring program is contingent on its purpose, which can range from detection of individual well leakage to demonstration of regional impact. The regulatory goals for permit-required monitoring conducted by operators on a well-by-well basis will differ from the scientific goals of a regional monitoring program conducted by the State. Vulnerability assessment: Identifying factors that increase the probability of transport of fluids from the hydrocarbon target zone to a protected groundwater zone enables the intensity of permit-required monitoring to be tiered by risk and also enables prioritization of regional monitoring of groundwater basins based on vulnerability. Risk factors include well integrity; proximity to existing wellbores and geologic features; wastewater disposal; vertical separation between the hydrocarbon and groundwater zones; and site-specific hydrogeology. Analyte choice: The choice of chemical analytes in a regulatory monitoring program is guided by the goals of detecting impact, assuring public safety, preventing resource degradation, and minimizing cost. Balancing these goals may be best served by tiered approach in which targeted analysis of specific chemical additives is triggered by significant changes in relevant but more easily analyzed constituents. Such an approach requires characterization of baseline conditions, especially in areas with long histories of oil and gas development. Monitoring technology: Monitoring a deep subsurface process or a long wellbore is more challenging than monitoring a surface industrial source. The requirement for monitoring multiple groundwater aquifers across a range of depths and of monitoring at deeper depths than is typical for regulatory monitoring programs requires consideration of monitoring technology, which can range from clusters of wells to multiple wells in a single wellbore to multi-level systems in a single cased wellbore.

ENVIRONMENTAL MONITORING AND ASSESSMENT PROGRAM: AGROECOSYSTEM 1992 PILOT PLAN

EPA Science Inventory

The Agroecosystem Resource Group (ARG) of the Environmental Protection Monitoring and Assessment Program (EMAP) has developed a five year program strategy for implementation of a suite of indicators for monitoring agroecosystem status and trends. he five-year period (1991-1995) i...

Integrated Analysis Tools for the NERRS System-Wide Monitoring Program Data

EPA Science Inventory

Standardized monitoring programs have vastly improved the quantity and quality of data that form the basis of environmental decision-making. One example is the NOAA-funded National Estuarine Research Reserve System (NERRS) System-wide Monitoring Program (SWMP) that was implement...

40 CFR 30.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2014 CFR

2014-07-01

... HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Reports and Records § 30.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award...

40 CFR 30.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2012 CFR

2012-07-01

... HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Reports and Records § 30.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award...

40 CFR 30.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Reports and Records § 30.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award...

40 CFR 30.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2013 CFR

2013-07-01

... HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Reports and Records § 30.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award...

20 CFR 437.40 - Monitoring and reporting program performance.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Monitoring and reporting program performance. 437.40 Section 437.40 Employees' Benefits SOCIAL SECURITY ADMINISTRATION UNIFORM ADMINISTRATIVE... Reports, Records, Retention, and Enforcement § 437.40 Monitoring and reporting program performance. (a...

CHARACTERIZATION OF SMALL ESTUARIES AS A COMPONENT OF A REGIONAL-SCALE MONITORING PROGRAM

EPA Science Inventory

Large-scale environmental monitoring programs, such as EPA's Environmental Monitoring and Assessment Program (EMAP), by nature focus on estimating the ecological condition of large geographic areas. Generally missing is the ability to provide estimates of condition of individual ...

Enterprise tools to promote interoperability: MonitoringResources.org supports design and documentation of large-scale, long-term monitoringprograms

NASA Astrophysics Data System (ADS)

Weltzin, J. F.; Scully, R. A.; Bayer, J.

2016-12-01

Individual natural resource monitoring programs have evolved in response to different organizational mandates, jurisdictional needs, issues and questions. We are establishing a collaborative forum for large-scale, long-term monitoring programs to identify opportunities where collaboration could yield efficiency in monitoring design, implementation, analyses, and data sharing. We anticipate these monitoring programs will have similar requirements - e.g. survey design, standardization of protocols and methods, information management and delivery - that could be met by enterprise tools to promote sustainability, efficiency and interoperability of information across geopolitical boundaries or organizational cultures. MonitoringResources.org, a project of the Pacific Northwest Aquatic Monitoring Partnership, provides an on-line suite of enterprise tools focused on aquatic systems in the Pacific Northwest Region of the United States. We will leverage on and expand this existing capacity to support continental-scale monitoring of both aquatic and terrestrial systems. The current stakeholder group is focused on programs led by bureaus with the Department of Interior, but the tools will be readily and freely available to a broad variety of other stakeholders. Here, we report the results of two initial stakeholder workshops focused on (1) establishing a collaborative forum of large scale monitoring programs, (2) identifying and prioritizing shared needs, (3) evaluating existing enterprise resources, (4) defining priorities for development of enhanced capacity for MonitoringResources.org, and (5) identifying a small number of pilot projects that can be used to define and test development requirements for specific monitoring programs.

Integration of structural health monitoring solutions onto commercial aircraft via the Federal Aviation Administration structural health monitoring research program

NASA Astrophysics Data System (ADS)

Swindell, Paul; Doyle, Jon; Roach, Dennis

2017-02-01

The Federal Aviation Administration (FAA) started a research program in structural health monitoring (SHM) in 2011. The program's goal was to understand the technical gaps of implementing SHM on commercial aircraft and the potential effects on FAA regulations and guidance. The program evolved into a demonstration program consisting of a team from Sandia National Labs Airworthiness Assurance NDI Center (AANC), the Boeing Corporation, Delta Air Lines, Structural Monitoring Systems (SMS), Anodyne Electronics Manufacturing Corp (AEM) and the FAA. This paper will discuss the program from the selection of the inspection problem, the SHM system (Comparative Vacuum Monitoring-CVM) that was selected as the inspection solution and the testing completed to provide sufficient data to gain the first approved use of an SHM system for routine maintenance on commercial US aircraft.

Improving Ecological Response Monitoring of Environmental Flows

NASA Astrophysics Data System (ADS)

King, Alison J.; Gawne, Ben; Beesley, Leah; Koehn, John D.; Nielsen, Daryl L.; Price, Amina

2015-05-01

Environmental flows are now an important restoration technique in flow-degraded rivers, and with the increasing public scrutiny of their effectiveness and value, the importance of undertaking scientifically robust monitoring is now even more critical. Many existing environmental flow monitoring programs have poorly defined objectives, nonjustified indicator choices, weak experimental designs, poor statistical strength, and often focus on outcomes from a single event. These negative attributes make them difficult to learn from. We provide practical recommendations that aim to improve the performance, scientific robustness, and defensibility of environmental flow monitoring programs. We draw on the literature and knowledge gained from working with stakeholders and managers to design, implement, and monitor a range of environmental flow types. We recommend that (1) environmental flow monitoring programs should be implemented within an adaptive management framework; (2) objectives of environmental flow programs should be well defined, attainable, and based on an agreed conceptual understanding of the system; (3) program and intervention targets should be attainable, measurable, and inform program objectives; (4) intervention monitoring programs should improve our understanding of flow-ecological responses and related conceptual models; (5) indicator selection should be based on conceptual models, objectives, and prioritization approaches; (6) appropriate monitoring designs and statistical tools should be used to measure and determine ecological response; (7) responses should be measured within timeframes that are relevant to the indicator(s); (8) watering events should be treated as replicates of a larger experiment; (9) environmental flow outcomes should be reported using a standard suite of metadata. Incorporating these attributes into future monitoring programs should ensure their outcomes are transferable and measured with high scientific credibility.

ENVIRONMENTAL MONITORING AND ASSESSMENT PROGRAM - AGROECOSYSTEM PILOT FIELD PROGRAM PLAN - 1993

EPA Science Inventory

The Agroecosystem Resource Group (ARG) of the Environmental Monitoring and Assessment Program (EMAP) has developed a five-year (1991-1995) strategy for the development, evaluation, and implementation of a suite of indicators for monitoring agroecosystem status and trends on a reg...

77 FR 71609 - Self-Help Homeownership Opportunity Program (SHOP) Grant Monitoring

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-03

... DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT [Docket No. FR-5603-N-89] Self-Help Homeownership Opportunity Program (SHOP) Grant Monitoring AGENCY: Office of the Chief Information Officer, HUD. ACTION...-Help Homeownership Opportunity Program (SHOP) Grant Monitoring. OMB Approval Number: 2506-0157. Form...

Results of Boron, Surfactant, and Cyanide Investigation, Beale AFB, California

DTIC Science & Technology

1991-07-01

ensure that their discharge does not produce instream toxicity. The Discharger shall carry-out the biotoxicity monitoring program in accordance with...Discharger shall implement the approved biotoxicity monitoring program. d. The Discharger shall submit the results of the biotoxicity monitoring program to

22 CFR 145.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2012 CFR

2012-04-01

... INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Reports and Records § 145.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award...

22 CFR 145.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2011 CFR

2011-04-01

... INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Reports and Records § 145.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award...

22 CFR 145.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2014 CFR

2014-04-01

... INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Reports and Records § 145.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award...

22 CFR 145.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2013 CFR

2013-04-01

... INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Reports and Records § 145.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award...

36 CFR 1210.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2014 CFR

2014-07-01

... INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Reports and Records § 1210.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award...

36 CFR 1210.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Reports and Records § 1210.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award...

36 CFR 1210.51 - Monitoring and reporting program performance.

Code of Federal Regulations, 2012 CFR

2012-07-01

... INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Reports and Records § 1210.51 Monitoring and reporting program performance. (a) Recipients are responsible for managing and monitoring each project, program, subaward, function or activity supported by the award...

Ecological Monitoring and Compliance Program 2008 Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, Dennis J.; Anderson, David C.; Hall, Derek B.

2009-04-30

The Ecological Monitoring and Compliance Program, funded through the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO), monitors the ecosystem of the Nevada Test Site (NTS) and ensures compliance with laws and regulations pertaining to NTS biota. This report summarizes the program’s activities conducted by National Security Technologies, LLC (NSTec), during calendar year 2008. Program activities included (a) biological surveys at proposed construction sites, (b) desert tortoise compliance, (c) ecosystem mapping and data management, (d) sensitive plant species monitoring, (e) sensitive and protected/regulated animal monitoring, (f) habitat monitoring, (g) habitat restoration monitoring, and (h) monitoring ofmore » the Nonproliferation Test and Evaluation Complex (NPTEC).« less

The Ocean Observatories Initiative Data Management and QA/QC: Lessons Learned and the Path Ahead

NASA Astrophysics Data System (ADS)

Vardaro, M.; Belabbassi, L.; Garzio, L. M.; Knuth, F.; Smith, M. J.; Kerfoot, J.; Crowley, M. F.

2016-02-01

The Ocean Observatories Initiative (OOI) is a multi-decadal, NSF-funded program that will provide long-term, near real-time cabled and telemetered measurements of climate variability, ocean circulation, ecosystem dynamics, air-sea exchange, seafloor processes, and plate-scale geodynamics. The OOI platforms consist of seafloor sensors, fixed moorings, and mobile assets containing over 700 operational instruments in the Atlantic and Pacific oceans. Rutgers University operates the Cyberinfrastructure (CI) component of the OOI, which acquires, processes and distributes data to scientists, researchers, educators and the public. It will also provide observatory mission command and control, data assessment and distribution, and long-term data management. The Rutgers Data Management Team consists of a data manager and four data evaluators, who are tasked with ensuring data completeness and quality, as well as interaction with OOI users to facilitate data delivery and utility. Here we will discuss the procedures developed to guide the data team workflow, the automated QC algorithms and human-in-the-loop (HITL) annotations that are used to flag suspect data (whether due to instrument failures, biofouling, or unanticipated events), system alerts and alarms, long-term data storage and CF (Climate and Forecast) standard compliance, and the lessons learned during construction and the first several months of OOI operations.

An integral wall model for Large Eddy Simulation (iWMLES) and applications to developing boundary layers over smooth and rough plates

NASA Astrophysics Data System (ADS)

Yang, Xiang; Sadique, Jasim; Mittal, Rajat; Meneveau, Charles

2014-11-01

A new wall model for Large-Eddy-Simulations is proposed. It is based on an integral boundary layer method that assumes a functional form for the local mean velocity profile. The method, iWMLES, evaluates required unsteady and advective terms in the vertically integrated boundary layer equations analytically. The assumed profile contains a viscous or roughness sublayer, and a logarithmic layer with an additional linear term accounting for inertial and pressure gradient effects. The iWMLES method is tested in the context of a finite difference LES code. Test cases include developing turbulent boundary layers on a smooth flat plate at various Reynolds numbers, over flat plates with unresolved roughness, and a sample application to boundary layer flow over a plate that includes resolved roughness elements. The elements are truncated cones acting as idealized barnacle-like roughness elements that often occur in biofouling of marine surfaces. Comparisons with data show that iWMLES provides accurate predictions of near-wall velocity profiles in LES while, similarly to equilibrium wall models, its cost remains independent of Reynolds number and is thus significantly lower compared to standard zonal or hybrid wall models. This work is funded by ONR Grant N00014-12-1-0582 (Dr. R. Joslin, program manager).

New non-stick expoxy-silicone water-based coatings part 1: Physical and surface properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garti, N.; Smith, J.

In search for tomorrow`s technology for water-based coating, Decora Manufacturing and The Hebrew University of Jerusalem, have initiated an intensive research program for designing, developing and manufacturing new coatings based on cross-linked, room temperature-cured silicone-expoxy resins. The new water-borne coatings have most exciting characteristics such as: non-stick properties, effective release, high lubricity, corrosion protection and abrasion resistance. The coatings are environmentally-friendly and easy to use. These coatings are ideal for marine, agricultural, industrial and maintenance applications. This paper brings quantitative measurements related to the dispersion technology (particle size, stability, shelf-life), to the non-stick properties (deicing, low surface energy, easy-release andmore » non-stick), lubricity, adhesion to substrates, viscosity, dynamic and static friction coefficients and environmental impact (low VOC, non-toxicity, low-leaching). The coating was tested in various industrial coating systems and was found to exhibit excellent non-stick and release properties. Special attention was given to Zebra Mussels, Quagga Mussels and other bacterial and algeal bioforms. The coating proved to be efficient as foul-release coating with very low biofouling adhesion. The low adhesion applied to many other substances in which foul-release means easy-clean and low-wear.« less

Oak Ridge Reservation annual site environmental report for 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koncinski, W.S.

1996-09-01

This report presents the details of the environmental monitoring and management program for the Oak Ridge Reservation. Topics discussed include: site background, climate, and operations; environmental compliance strategies; effluent monitoring; environmental management program including environmental restoration, decontamination and decommissioning, technology development, and public involvement; effluent monitoring of airborne discharges, liquid discharges, toxicity control and monitoring, biological monitoring and abatement; environmental surveillance which encompasses meteorological monitoring, ambient air monitoring, surface water monitoring, soils monitoring, sediment monitoring, and contamination of food stuffs monitoring; radiation doses; chemical exposures; ground water monitoring; and quality assurance.

Proceedings of the Tri-Service Conference on Corrosion (1987) Held at the Air Force Academy, Colorado on 5-7 May 1987.

DTIC Science & Technology

1987-05-01

j, ’er-,t- -- Case Studies of .- ’." Failures", Proceedinqs, 198O Tri-Ser vice Conference on Corrosion, AFWAL-TR-81- 401(, 1o1. 1, 2’.1-270, (II1). 3...Spiehler, 1981. Gulf of Mexico Study of "v’-. Biofouling on OTEC heat exchanger candidate alloys. Materials Performance 8:16-21. - Little, B. 1980... Case Studies Figure 2 shows the configuration of a straight shank attachment lug without bushing. All lugs, with or without bushing, that were

Corrosion and Biofouling on the Non-Heat-Exchanger Surfaces of an Ocean Thermal Energy Conversion Power Plant. A Survey

DTIC Science & Technology

1979-05-01

8217• . 5-nitrothia~ol, 1 0 6 pesticides such as DDT1 0 6 and Nopcocide, 1 0 7 and juverile hormones. 1 0 8 Organometallic compounds that have...Technology, Vol. 1, No. 3, pp. 321-327 (1966). 61. Basil . .J. 1., "Report of Test , t Plastic Panels Exoosed in Sea- wate for One Year at Wrightsville Reacli...34 Proceedings of Controlled Release Pesticides Symposium, Wright State UnIv., Dayton, Ohict (1975). 85. Dick, R. J. et al., "Analysis of Buoy Coating

Biofouling-resistant ceragenin-modified materials and structures for water treatment

DOEpatents

Hibbs, Michael; Altman, Susan J.; Jones, Howland D. T.; Savage, Paul B.

2013-09-10

This invention relates to methods for chemically grafting and attaching ceragenin molecules to polymer substrates; methods for synthesizing ceragenin-containing copolymers; methods for making ceragenin-modified water treatment membranes and spacers; and methods of treating contaminated water using ceragenin-modified treatment membranes and spacers. Ceragenins are synthetically produced antimicrobial peptide mimics that display broad-spectrum bactericidal activity. Alkene-functionalized ceragenins (e.g., acrylamide-functionalized ceragenins) can be attached to polyamide reverse osmosis membranes using amine-linking, amide-linking, UV-grafting, or silane-coating methods. In addition, silane-functionalized ceragenins can be directly attached to polymer surfaces that have free hydroxyls.

International Conference on Marine Corrosion and Fouling (5th), held 19-23 May 1980, Barcelona (Spain).

DTIC Science & Technology

1980-12-31

aguas de puertos i talianos." C.A. Viviani and L.H. Disalvo ( Chile ) :,"Biofouling in a north-central Chilean coastal bay." A.F.A. Ghobashy and A.K. Hassan...34Estudio del mechanismo de formaci6n de incrustationes en enfriadores por el uso de agua de mer." S.M. Coelho de Souza Medeiros Bastos and L.R...naval con cubierta de pinturas en agua de mar sintetica." T. Skoulikidis and P. Vassiliou (Greece): "Kinetic data on the leaching of 152?- antifouling

Boreal partners in flight: Working together to build a regional research and monitoring program

USGS Publications Warehouse

Handel, Colleen M.; Bonney, Rick; Pashley, David N.; Cooper, Robert J.; Niles, Larry

1999-01-01

Boreal regions of western North America regularly support breeding populations of 130 species of landbirds, including 68 Nearctic-Neotropical migrants. Primary conservation concerns within the region include increased timber harvesting, insect outbreaks, fire suppression, mining, impacts of military training activities, urbanization, and recreational activities. Under auspices of Partners in Flight, biologists, land and resource managers, and conservationists from Alaska and western Canada have combined efforts to develop a regional research and monitoring program for landbirds. An experimental monitoring program has been under way during the past four years to test the relative statistical power and cost-effectiveness of various monitoring methods in Alaska. Joint efforts currently include the Alaska Checklist Project on National Wildlife Refuges, 75 Breeding Bird Surveys along the road system, 122 Off-road Point Count routes, 27 Monitoring Avian Productivity and Survivorship banding sites, and 8 migration banding stations. The ultimate goal is to design a comprehensive monitoring program that is sensitive to changes in population size, survival rates, and productivity, but robust enough to accommodate logistical constraints that arise when working in vast, roadless areas with limited funds and staff. Primary challenges that must be faced to assure the long-term future of such a program are obtaining long-term commitment from resource agencies in the region, integrating this program with other national and regional programs that address those species and habitats that are inadequately monitored by established techniques, and developing cooperative research, monitoring, and management programs at the landscape level.

The implementation of medical monitoring programs following potentially hazardous exposures: a medico-legal perspective.

PubMed

Vearrier, David; Greenberg, Michael I

2017-11-01

Clinical toxicologists may be called upon to determine the appropriateness of medical monitoring following documented or purported exposures to toxicants in the occupational, environmental, and medical settings. We searched the MEDLINE database using the Ovid ® search engine for the following terms cross-referenced to the MeSH database: ("occupational exposures" OR "environmental exposures") AND ("physiologic monitoring" OR "population surveillance"). The titles and abstracts of the resulted articles were reviewed for relevance. We expanded our search to include non-peer-reviewed publications and gray literature and resources using the same terms as utilized in the MEDLINE search. There were a total of 48 relevant peer-reviewed and non-peer-reviewed publications. Publications excluded contained no information relevant to medical monitoring following potentially harmful toxicologic exposures, discussed only worker screening/surveillance and/or population biomonitoring, contained redundant information, or were superseded by more recent information. Approaches to medical monitoring: A consensus exists in the peer-reviewed medical literature, legal literature, and government publications that for medical monitoring to be a beneficial public health activity, careful consideration must be given to potential benefits and harms of the program. Characteristics of the exposure, the adverse human health effect, the screening test, and the natural history of the disease are important in determining whether an exposed population will reap a net benefit or harm from a proposed monitoring program. Broader interpretations of medical monitoring: Some have argued that medical monitoring programs should not be limited to exposure-related outcomes but should duplicate general preventive medicine efforts to improve public health outcomes although an overall reduction of morbidity, mortality and disability by modifying correctable risk factors and disease conditions. This broader approach is inconsistent with the targeted approach advocated by the Agency for Toxic Substances and Disease Registry and the United States Preventive Services Task Force and the bulk of the peer-reviewed medical literature. Medical monitoring in legal contexts: Numerous medical monitoring actions have been litigated. Legal rationales for allowing medical monitoring claims often incorporate some of the scientific criteria for the appropriateness of monitoring programs. In the majority of cases in which plaintiffs were awarded medical monitoring relief, plaintiffs were required to demonstrate both that the condition for which medical monitoring was sought could be detected early, and that early detection and treatment will improve morbidity and mortality. However, the treatment of medical monitoring claims varies significantly depending upon jurisdiction. Examples of large-scale, comprehensive medical monitoring programs: Large-scale, comprehensive medical monitoring programs have been implemented, such as the Fernald Medical Monitoring Program and the World Trade Center Health Program, both of which exceeded the scope of medical monitoring typically recommended in the peer-reviewed medical literature and the courts. The Fernald program sought to prevent death and disability due to non-exposure-related conditions in a manner similar to general preventive medicine. The World Trade Center Health Program provides comprehensive medical care for World Trade Center responders and may be viewed as a large-scale, federally--funded research effort, which distinguishes it from medical monitoring in a medico-legal context. Synthesis of public health approaches to medical monitoring: Medical monitoring may be indicated following a hazardous exposure in limited circumstances. General causation for a specific adverse health effect must be either established by scientific consensus through a formal causal analysis using a framework such as the Bradford-Hill criteria. The exposure must be characterized and must be of sufficient severity that the exposed population has a significantly elevated risk of an adverse health effect. Monitoring must result in earlier detection of the condition than would otherwise occur and must confer a benefit in the form of primary, secondary or tertiary prevention. Outcome tables may be of use in describing the potential benefits and harms of a proposed monitoring program. In the context of litigation, plaintiffs may seek medical monitoring programs after documented or putative exposures. The role of the clinical toxicologist, in this setting, is to evaluate the scientific justifications and medical risks and assist the courts in determining whether monitoring would be expected to result in a net public health benefit.

LESSONS-LEARNED AND SUCCESS STORIES FROM EPA'S REAL-TIME ENVIRONMENTAL MONITORING, DATA DELIVERY, AND PUBLIC OUTREACH PROGRAM

EPA Science Inventory

TTSD has completed a series of technology transfer and risk communication handbooks, case studies, and summary reports for community-based environmental monitoring projects under EPA's Real-Time Environmental Monitoring, Data Delivery, and Public Outreach Program. The Program tak...

49 CFR 227.103 - Noise monitoring program.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Noise monitoring program. 227.103 Section 227.103..., DEPARTMENT OF TRANSPORTATION OCCUPATIONAL NOISE EXPOSURE Occupational Noise Exposure for Railroad Operating Employees. § 227.103 Noise monitoring program. (a) Schedule. A railroad shall develop and implement a noise...

United States of America Ocean Dumping Report for Calendar Year 1981. Dredged Material.

DTIC Science & Technology

1982-06-01

to monitoring studies under the Disposal Area Monitoring System ( DAHOS ) program. The program is designed to identify and evaluate impacts resulting...sites. The DAHOS program continually contributes to the development of new monitoring methodologies that reflect on the efficiency of field observations

25 CFR 276.9 - Monitoring and reporting program performances.

Code of Federal Regulations, 2010 CFR

2010-04-01

... frequency with which the performance reports will be submitted with the Request for Advance or Reimbursement... 25 Indians 1 2010-04-01 2010-04-01 false Monitoring and reporting program performances. 276.9... reporting program performances. (a) Grantees shall constantly monitor the performance under grant-supported...

Patterns of Success: Online Self-Monitoring in a Web-Based Behavioral Weight Control Program

PubMed Central

Krukowski, Rebecca A.; Harvey-Berino, Jean; Bursac, Zoran; Ashikaga, Taka; West, Delia Smith

2016-01-01

Objectives Online weight control technologies could reduce barriers to treatment, including increased ease and convenience of self-monitoring. Self-monitoring consistently predicts outcomes in behavioral weight loss programs; however, little is known about patterns of self-monitoring associated with success. Methods The current study examines 161 participants (93% female; 31% African-American; mean BMI=35.7±5.7) randomized to a 6-month online behavioral weight control program which offered weekly group “chat” sessions and online self-monitoring. Self-monitoring log-ins were continuously monitored electronically during treatment and examined in association with weight change and demographics. Weekend and weekday log-ins were examined separately and length of periods of continuous self-monitoring were examined. Results We found that 91% of participants logged in to the self-monitoring webpage at least once. Over 6 months, these participants monitored on an average of 28% of weekdays and 17% of weekend days, with most log-ins earlier in the program. Women were less likely to log-in, and there were trends for greater self-monitoring by older participants. Race, education and marital status were not significant predictors of self-monitoring. Both weekday and weekend log-ins were significant independent predictors of weight loss. Patterns of consistent self-monitoring emerged early for participants who went on to achieve greater than a five percent weight loss. Conclusions Patterns of online self-monitoring were strongly associated with weight loss outcomes. These results suggest a specific focus on consistent self-monitoring early in a behavioral weight control program might be beneficial for achieving clinically significant weight losses. PMID:22545978

10 CFR 600.341 - Monitoring and reporting program and financial performance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Monitoring and reporting program and financial performance. 600.341 Section 600.341 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS FINANCIAL... Organizations Post-Award Requirements § 600.341 Monitoring and reporting program and financial performance. (a...

34 CFR 303.171 - Supervision and monitoring of programs.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 34 Education 2 2010-07-01 2010-07-01 false Supervision and monitoring of programs. 303.171 Section 303.171 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF...-Application Requirements § 303.171 Supervision and monitoring of programs. Each application must include...

34 CFR 303.171 - Supervision and monitoring of programs.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 34 Education 2 2011-07-01 2010-07-01 true Supervision and monitoring of programs. 303.171 Section 303.171 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF...-Application Requirements § 303.171 Supervision and monitoring of programs. Each application must include...

40 CFR 258.58 - Implementation of the corrective action program.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) SOLID WASTES CRITERIA FOR MUNICIPAL SOLID WASTE LANDFILLS Ground-Water Monitoring and Corrective...) Establish and implement a corrective action ground-water monitoring program that: (i) At a minimum, meet the requirements of an assessment monitoring program under § 258.55; (ii) Indicate the effectiveness of the...

40 CFR 257.28 - Implementation of the corrective action program.

Code of Federal Regulations, 2014 CFR

2014-07-01

...-Municipal Non-Hazardous Waste Disposal Units Ground-Water Monitoring and Corrective Action § 257.28... corrective action ground-water monitoring program that: (i) At a minimum, meets the requirements of an assessment monitoring program under § 257.25; (ii) Indicates the effectiveness of the corrective action...

40 CFR 257.28 - Implementation of the corrective action program.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-Municipal Non-Hazardous Waste Disposal Units Ground-Water Monitoring and Corrective Action § 257.28... corrective action ground-water monitoring program that: (i) At a minimum, meets the requirements of an assessment monitoring program under § 257.25; (ii) Indicates the effectiveness of the corrective action...

40 CFR 258.58 - Implementation of the corrective action program.

Code of Federal Regulations, 2012 CFR

2012-07-01

... WASTES CRITERIA FOR MUNICIPAL SOLID WASTE LANDFILLS Ground-Water Monitoring and Corrective Action § 258... implement a corrective action ground-water monitoring program that: (i) At a minimum, meet the requirements of an assessment monitoring program under § 258.55; (ii) Indicate the effectiveness of the corrective...

40 CFR 258.58 - Implementation of the corrective action program.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) SOLID WASTES CRITERIA FOR MUNICIPAL SOLID WASTE LANDFILLS Ground-Water Monitoring and Corrective...) Establish and implement a corrective action ground-water monitoring program that: (i) At a minimum, meet the requirements of an assessment monitoring program under § 258.55; (ii) Indicate the effectiveness of the...

40 CFR 258.58 - Implementation of the corrective action program.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) SOLID WASTES CRITERIA FOR MUNICIPAL SOLID WASTE LANDFILLS Ground-Water Monitoring and Corrective...) Establish and implement a corrective action ground-water monitoring program that: (i) At a minimum, meet the requirements of an assessment monitoring program under § 258.55; (ii) Indicate the effectiveness of the...

40 CFR 257.28 - Implementation of the corrective action program.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-Municipal Non-Hazardous Waste Disposal Units Ground-Water Monitoring and Corrective Action § 257.28... corrective action ground-water monitoring program that: (i) At a minimum, meets the requirements of an assessment monitoring program under § 257.25; (ii) Indicates the effectiveness of the corrective action...

40 CFR 257.28 - Implementation of the corrective action program.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-Hazardous Waste Disposal Units Ground-Water Monitoring and Corrective Action § 257.28 Implementation of the... ground-water monitoring program that: (i) At a minimum, meets the requirements of an assessment monitoring program under § 257.25; (ii) Indicates the effectiveness of the corrective action remedy; and (iii...

A plan for the North American Bat Monitoring Program (NABat)

USGS Publications Warehouse

Loeb, Susan C.; Rodhouse, Thomas J.; Ellison, Laura E.; Lausen, Cori L.; Reichard, Jonathan D.; Irvine, Kathryn M.; Ingersoll, Thomas E.; Coleman, Jeremy; Thogmartin, Wayne E.; Sauer, John R.; Francis, Charles M.; Bayless, Mylea L.; Stanley, Thomas R.; Johnson, Douglas H.

2015-01-01

The purpose of the North American Bat Monitoring Program (NABat) is to create a continent-wide program to monitor bats at local to rangewide scales that will provide reliable data to promote effective conservation decisionmaking and the long-term viability of bat populations across the continent. This is an international, multiagency program. Four approaches will be used to gather monitoring data to assess changes in bat distributions and abundances: winter hibernaculum counts, maternity colony counts, mobile acoustic surveys along road transects, and acoustic surveys at stationary points. These monitoring approaches are described along with methods for identifying species recorded by acoustic detectors. Other chapters describe the sampling design, the database management system (Bat Population Database), and statistical approaches that can be used to analyze data collected through this program.

Program evaluation of remote heart failure monitoring: healthcare utilization analysis in a rural regional medical center.

PubMed

Riley, William T; Keberlein, Pamela; Sorenson, Gigi; Mohler, Sailor; Tye, Blake; Ramirez, A Susana; Carroll, Mark

2015-03-01

Remote monitoring for heart failure (HF) has had mixed and heterogeneous effects across studies, necessitating further evaluation of remote monitoring systems within specific healthcare systems and their patient populations. "Care Beyond Walls and Wires," a wireless remote monitoring program to facilitate patient and care team co-management of HF patients, served by a rural regional medical center, provided the opportunity to evaluate the effects of this program on healthcare utilization. Fifty HF patients admitted to Flagstaff Medical Center (Flagstaff, AZ) participated in the project. Many of these patients lived in underserved and rural communities, including Native American reservations. Enrolled patients received mobile, broadband-enabled remote monitoring devices. A matched cohort was identified for comparison. HF patients enrolled in this program showed substantial and statistically significant reductions in healthcare utilization during the 6 months following enrollment, and these reductions were significantly greater compared with those who declined to participate but not when compared with a matched cohort. The findings from this project indicate that a remote HF monitoring program can be successfully implemented in a rural, underserved area. Reductions in healthcare utilization were observed among program participants, but reductions were also observed among a matched cohort, illustrating the need for rigorous assessment of the effects of HF remote monitoring programs in healthcare systems.