Sample records for water recirculation systems

  1. Unit process engineering for water quality control and biosecurity in marine water recirculating systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High-intensity systems that treat and recirculate water must maintain a culture environment that can sustain near optimum fish health and growth at the design carrying capacity. Water recirculating systems that use centralized treatment systems can benefit from the economies of scale to decrease th...

  2. Water quality trials in four recirculating aquacultural system configurations

    Microsoft Academic Search

    Sahdev Singh; James Ebeling; Fredrick Wheaton

    1999-01-01

    Four circular, 2000-l, fiberglass tanks in four independent, indoor recirculating aquacultural systems were stocked with hybrid striped bass fingerlings (60-g average weight) at similar densities (320 fish\\/tank at the start of the study). The four systems represented four different recirculating system configurations as obtained by the combination of two types of biofilters (trickling and bead) and two types of solids

  3. Control strategies for domestic hot water recirculation systems

    SciTech Connect

    Goldner, F.S.

    1999-07-01

    The purpose of a domestic hot water (DHW) recirculation system is to decrease the time spent waiting for the water to be delivered at acceptable temperatures when called for and also decrease the subsequent water consumption. The research detailed in this paper considered whether it is necessary to continuously run these recirculation pumps, as is general practice, or whether it is possible to reduce DHW system energy consumption by operating these pumps with some type of control strategy. Three different control strategies were evaluated by employing detailed monitoring. The different operating modes were: (1) base case (continuous operation), (2) shutdown during the overnight period, (3) shutdown during the peak morning and evening periods, and (4) cycling by a return line aquastat set at 110 F (61 C). In order to accomplish the research, six sites each had an aquastat installed onto the DHW return line and a programmable timeclock wired into the pump. The analysis identifies the relative energy use for each of the strategies during four round-robin rounds of two weeks each during the spring, summer, fall, and winter periods. When compared to the base case, (pump running 24 hours per day), Strategy B saves an average of 6%, Strategy C saves 6%, and Strategy D saves 11% of the DHW portion of a building's DHW energy requirements annually. This is significant in that for Strategy D, this translates into a savings of 4% of the building's total annual fuel bill. All of the control strategies evaluated were simple and employed low-cost devices (under $250 installed), which should help in achieving an extremely large implementation rate for the control strategy recommended. Tenant water quality survey questionnaires show that there was always an acceptable level of satisfaction, regardless of system control strategy.

  4. Final cooling of coke oven gas using a closed-loop, recirculated wash-water system

    SciTech Connect

    Watkins, R.E.; Burcaw, K.R.

    1983-01-01

    Bethlehem Steel Corporation has developed a closed-loop, recirculated wash-water system for the final cooling of coke oven gas streams. The system employs physical separation of suspended solids from the cooling water, indirect cooling of the recirculating water, and injection of a small amount of a water-immiscible solvent to minimise the deposition of naphthalenic solids in the indirect heat exchanger. A process patent (US Patent 4.234.389) has been awarded to Bethlehem for the solvent-injection portion of the process. Based on the results of plant trials, the system has been proven to require less capital investment and to be more economical and more reliable to operate than the standard recirculated wash-oil systems. When compared with existing wash-water systems, the system has the advantage of eliminating the atmospheric discharges associated with open cooling towers.

  5. Design and Evaluation of Recirculating Water Systems for Maintenance and Propagation of Freshwater Mussels

    Microsoft Academic Search

    William F. Henley; Lora L. Zimmerman; Richard J. Neves; Mark R. Kidd

    2001-01-01

    A complete system for culturing, rearing, and holding juvenile and adult freshwater mussels (Unionidae) was designed and evaluated for use at hatcheries and research facilities. The system includes air delivery, water conditioning and delivery, algal culturing and automated algal feed delivery, and air-driven water-recirculating units. These systems are appropriate for holding and conditioning adult mussels for spawning, as well as

  6. Ozonation of a recirculating rainbow trout culture system II. Effects on microscreen filtration and water quality

    Microsoft Academic Search

    Steven T. Summerfelt; Joseph A. Hankins; Amy L. Weber; Martin D. Durant

    1997-01-01

    Ozone was added to water in a recirculating rainbow trout (Oncorhynchus mykiss) culture system just prior to the culture tanks in order to oxidize nitrite and organic material, improve overall water quality, and assist removal of solids across the microscreen filter. Data from four 8-week studies on ozonation and an 8-week no ozone control indicated that adding ozone reduced the

  7. Observations on side-swimming rainbow trout Oncorhynchus mykiss in water recirculation aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During a controlled 6-month study using six replicated water recirculation aquaculture systems (WRAS), it was observed that rainbow trout Oncorhynchus mykiss in all WRAS exhibited a higher-than-normal prevalence of side-swimming (i.e. controlled, forward swimming, but with misaligned orientation suc...

  8. Water quality and rainbow trout performance in a Danish Model Farm recirculating system: Comparison with a flow through system

    Microsoft Academic Search

    Emmanuelle Roque d’orbcastel; Jean-Paul Blancheton; Alain Belaud

    2009-01-01

    The objective was to compare water quality and fish growth and mortality in a pilot scale recirculating system (RS) and a control tank in flow through system (FTS). The RS was designed after the Danish Model Trout Farm and operated with a make up water renewal rate of 9m3kg-1 of fish produced. RS water quality did not decrease significantly with

  9. Particle sieve analysis for determining solids removal efficiency of water treatment components in a recirculating aquaculture system

    Microsoft Academic Search

    Timothy J. Pfeiffer; Andrew Osborn; Megan Davis

    2008-01-01

    Recirculating aquaculture systems offer potential finfish production units for small-scale entities as well as large-scale operations. However, the water treatment components of such systems require efficient and proper operation to assure successful production. This study evaluated the solids removal ability of three water treatment components in a two-tank recirculating aquaculture system (28m3) utilized for the warmwater production of tilapia. The

  10. Microparticles in recirculating aquaculture systems: particle size analysis of culture water from a commercial Atlantic salmon site

    Microsoft Academic Search

    R. N. Patterson; K. C. Watts

    2003-01-01

    As part of a larger study of micro-particles in a recirculating, cold water aquaculture system for juvenile Atlantic salmon (Salmo salar), particle size analyses were carried out on the culture and makeup waters over several months followed by samples of feed stirred in water. The particle size distributions followed the power law described in [Aquacult. Eng. 19 (1999): 259] but

  11. An integrated recirculating aquaculture system (RAS) for land-based fish farming: The effects on water quality and fish production

    Microsoft Academic Search

    Shi-Yang Zhang; Gu Li; Hui-Bi Wu; Xing-Guo Liu; Yan-Hong Yao; Ling Tao; Huang Liu

    To mitigate the serious water pollution caused by the rapid expansion of the aquaculture industry in recent years, the development of improved aquaculture systems with more efficient water usage and less environmental impact has become essential. In this study, a land-based recirculating aquaculture system (RAS) was established that consisted of purification units (i.e., a primary biological pond, two parallel horizontal

  12. Effects of Yucca shidigera Extract on Water Quality and Fish Growth in Recirculating-Water Aquaculture Systems

    Microsoft Academic Search

    James H. Tidwell; Carl D. Webster; Julia A. Clark; Daniel H. Yancey

    1992-01-01

    In livestock industries such as poultry and swine, an extract of the Yucca shidigera plant has shown promise in controlling ammonia buildup in production facilities. In three trials, effects of Y. shidigera extract on ammonia levels and fish growth in recirculating-water aquaculture systems were evaluated. When added to in vitro ammonia solutions, extract concentrations of 0.043% and 0.43% caused a

  13. The effects of ozone and water exchange rates on water quality and rainbow trout Oncorhynchus mykiss performance in replicated water recirculating systems

    Microsoft Academic Search

    John Davidson; Christopher Good; Carla Welsh; Steven Summerfelt

    2011-01-01

    Rainbow trout Oncorhynchus mykiss performance and water quality were evaluated and compared within six replicated 9.5m3 water recirculating aquaculture systems (WRAS) operated with and without ozone at various water exchange rates. Three separate studies were conducted: (1) low water exchange (0.26% of the total recycle flow) with and without ozone; (2) low water exchange with ozone versus high water exchange

  14. Exhaust gas recirculation system

    SciTech Connect

    Rachedi, S.H.

    1983-08-30

    An engine exhaust gas recirculation (EGR) system is provided in which a sonic flow EGR valve is moved to open positions to establish a different constant rate of flow at each open position of the EGR valve in response to air pressure acting on a servo means secured to the valve, the air pressure force being controlled by changes in a control vacuum opposing the air pressure force and modified by an air bleed device as a function of changes in engine exhaust gas backpressure levels, to provide an EGR valve movement that varies essentially in proportion to changes in engine air flow.

  15. The performance and impact of a bubble-wash bead filter in a recirculating green water larval culture system for delta smelt ( Hypomesus transpacificus)

    Microsoft Academic Search

    Tien-Chieh Hung; Raul H. Piedrahita

    2011-01-01

    Delta smelt are cultured at the UC Davis Fish Conservation and Culture Lab (FCCL) for research purposes. The culture systems used are based on recirculation technology to ensure optimum water quality for the fish at each life stage. Larval culture takes place in recirculation systems with green water to which a Nannochloropsis algal concentrate is added to maintain a turbidity

  16. The effects of carbon dioxide on performance and histopathology of rainbow trout Oncorhynchus mykiss in water recirculation aquaculture systems

    Microsoft Academic Search

    Christopher Good; John Davidson; Carla Welsh; Kevin Snekvik; Steven Summerfelt

    2010-01-01

    Chronic exposure to elevated levels of dissolved carbon dioxide (CO2) has been linked to reduced growth, physiological disturbances and negative health outcomes in intensively reared fish. Although pumping to a degassing tower can lower concentrations of dissolved CO2 in water recirculation aquaculture systems (WRAS), pumping can be a significant cost for operators. A 6-month trial was conducted to compare the

  17. The use of an open channel, low pressure UV reactor for water treatment in low head recirculating aquaculture systems (LH-RAS)

    Microsoft Academic Search

    Hadas Mamane; Angelo Colorni; Ido Bar; Ido Ori; Noam Mozes

    2010-01-01

    This study examined the effectiveness of an open channel, low pressure (LP), ultraviolet (UV) reactor for water treatment in a low head (LH) recirculating aquaculture system (RAS). Currently available UV reactors use high pressure pumps and submerged bulbs. The reactor in this study makes use of the head gained by the water recirculation of the LH-RAS without the need for

  18. Hexachlorobenzene uptake by fathead minnows and macroinvertebrates in recirculating sediment/water systems

    SciTech Connect

    Schuytema, G.S.; Krawczyk, D.F.; Griffis, W.L.; Nebeker, A.V.; Robideaux, M.L.

    1990-01-01

    Fathead minnow (Pimephales promelas), the worm, Lumbriculus variegatus, and the amphipods Hyalella azteca and Gammarus lacustris were exposed to hexachlorobenzene (HCB) in water with and without a bed of HCB-spiked sediment. Water HCB concentrations were maintained by recirculation through HCB-packed columns. Recirculating HCB-bound particulates and possibly eroded HCB particulates were an added source of HCB in addition to the sediment bed. Significant bioaccumulation of HCB in animal tissues was observed in water-only and water-sediment exposures. The presence of the HCB-spiked sediment did not result in a significant increase in the uptake of HCB by the organisms, but there was a substantial increase in sediment HCB levels over time. Higher tissue HCB levels in aquaria without sediment suggest that the sediment was a more efficient sink for HCB than the organisms.

  19. Using computer spreadsheets for water flow and biofilter sizing in recirculating aquaculture production systems

    Microsoft Academic Search

    Thomas M Losordo; Alexander O Hobbs

    2000-01-01

    North Carolina State University has been active in the development, evaluation and demonstration of recirculating aquaculture technology since 1989. In the process, numerous engineering and economic spreadsheets (worksheets) have been developed to assist in the design and analysis of these systems. The spreadsheet described in this paper is based on a set of mass balance equations developed and described by

  20. Disinfection of water in recirculating aquaculture systems with peracetic acid (PAA)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The disinfection behaviour of peracetic acid (PAA) in recirculating aquaculture systems (RAS) was investigated. Peracetic acid is a strong oxidizing agent found in various concentrations in different products. Three Wofasteril PAA products (E400 (c), Lspecical; AC 150) were tested in vitro for the...

  1. Effect of flow rate on water quality parameters and plant growth of water spinach (Ipomoea aquatica) in an aquaponic recirculating system

    Microsoft Academic Search

    Azizah Endut; Ahmad Jusoh; Nora’aini Ali; W. N. S. Wan Nik; Anuar Hassan

    2009-01-01

    Recirculating aquaculture–hydroponic systems were designed to provide an artificial, controlled environment that optimizes the growth of fish (or other aquatic species) and soil-less plants, complete control of water quality, the production schedule and the fish product, while conserving water resources. Nutrients removal such as inorganic nitrogen and phosphate is essential for aquaculture wastewater treatment to protect receiving waters from eutrophication

  2. Combustion-gas recirculation system

    DOEpatents

    Baldwin, Darryl Dean (Lacon, IL)

    2007-10-09

    A combustion-gas recirculation system has a mixing chamber with a mixing-chamber inlet and a mixing-chamber outlet. The combustion-gas recirculation system may further include a duct connected to the mixing-chamber inlet. Additionally, the combustion-gas recirculation system may include an open inlet channel with a solid outer wall. The open inlet channel may extend into the mixing chamber such that an end of the open inlet channel is disposed between the mixing-chamber inlet and the mixing-chamber outlet. Furthermore, air within the open inlet channel may be at a pressure near or below atmospheric pressure.

  3. Water Treatment and Performance Characteristics Evaluation of a Pilot-Scale Recirculating Aquaculture System

    Microsoft Academic Search

    Yan Zaisheng; Liu Changfa; Wang Shihe; He Jie; Liu Yuan; Zhang Liyong; Zhang Junxin

    2008-01-01

    To minimize the impact on the environment and land requirements, a pilot-scale recirculating aquaculture system was engineered and investigated in a greenhouse. The system included a three-step particulates separation device, fluidized bed reactors (FBR), UV treatment and cooling. Japanese flounder (Paralichthys olivaceus) were raised from initial mean weight 4.9 plusmn 0.6g to final mean weight 35.8 plusmn 14.6g after 140

  4. Effects of alkalinity on ammonia removal, carbon dioxide stripping, and system pH in semi-commercial scale water recirculating aquaculture systems operated with moving bed bioreactors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    When operating water recirculating systems (RAS) with high make-up water flushing rates in locations that have low alkalinity in the raw water, such as Norway, knowledge about the required RAS alkalinity concentration is important. Flushing RAS with make-up water containing low alkalinity washes out...

  5. Observations on Side-Swimming Rainbow Trout in Water Recirculation Aquaculture Systems

    PubMed Central

    Good, Christopher; Davidson, John; Kinman, Christin; Kenney, P. Brett; Bæverfjord, Grete; Summerfelt, Steven

    2014-01-01

    Abstract During a controlled 6-month study using six replicated water recirculation aquaculture systems (WRASs), it was observed that Rainbow Trout Oncorhynchus mykiss in all WRASs exhibited a higher-than-normal prevalence of side swimming (i.e., controlled, forward swimming but with misaligned orientation such that the fish's sagittal axis is approximately parallel to the horizontal plane). To further our understanding of this abnormality, a substudy was conducted wherein side swimmers and normally swimming fish were selectively sampled from each WRAS and growth performance (length, weight), processing attributes (fillet yield, visceral index, ventrum [i.e., thickness of the ventral “belly flap”] index), blood gas and chemistry parameters, and swim bladder morphology and positioning were compared. Side swimmers were found to be significantly smaller in length and weight and had less fillet yield but higher ventrum indices. Whole-blood analyses demonstrated that, among other things, side swimmers had significantly lower whole-blood pH and higher Pco 2. Side swimmers typically exhibited swim bladder malformations, although the positive predictive value of this subjective assessment was only 73%. Overall, this study found several anatomical and physiological differences between side-swimming and normally swimming Rainbow Trout. Given the reduced weight and fillet yield of market-age side swimmers, producers would benefit from additional research to reduce side-swimming prevalence in their fish stocks. Received March 20, 2014; accepted May 20, 2014 PMID:25250476

  6. Phosphorus removal in a marine prototype, recirculating aquaculture system

    Microsoft Academic Search

    Yoram Barak; Eddie Cytryn; Iliya Gelfand; Michael Krom; Jaap van Rijn

    2003-01-01

    Phosphorus dynamics were examined in a prototype, zero-discharge, marine-recirculating system. Operation of the system without discharge of water and sludge was enabled by recirculation of effluent water through two separate treatment loops. Surface water from the fish basin was pumped over a trickling filter in one loop, while bottom-water was recirculated through a sedimentation basin followed by a fluidized bed

  7. Evaluation of air-lift pump capabilities for water delivery, aeration, and degasification for application to recirculating aquaculture systems

    Microsoft Academic Search

    J. Clay Loyless; Ronald F Malone

    1998-01-01

    A methodology is demonstrated for evaluating the feasibility of using air-lift pumps for water movement, aeration, and degasification in a recirculating aquaculture system. A set of empirical equations are presented modeling the performance of a 5.08-cm (2?) diameter air-lift submerged 91.44 cm (36?) with a 15.24-cm (6?) lift operated at 28–142 l min?1 (1–5 scfm) of air injection. A steady

  8. In-tank aeration, a necessary compliment of loaded systems in an airlift recirculating aquaculture system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water treatment components in recirculating aquaculture systems in generally address solids removal, nitrification, circulation, aeration, and degasification. Airlift pumps in a recirculating aquaculture system can address water circulation, aeration, and degasification. Recent data indicates oxygen...

  9. Influence of sulfate-reducing bacteria and thiogenic bacteria on corrosion of carbon steel in refinery recirculating water systems

    SciTech Connect

    Teslya, B.M.; Chupareva, I.E.; Burlov, V.V.

    1987-07-01

    The influence of SRB and TB on the kinetics of carbon steel corrosion was investigated in recirculating water at the Kirishi refinery and in cumulative cultures of the SRB and TB obtained by inoculating elective nutrient media with the recirculating water (300 ml of water per 1000 ml of medium). The concentrations of SRB and TB in the recirculating water and in the cumulative cultures were determined by the serial dilution method. The corrosion activity of the microorganisms was evaluated on the basis of carbon steel specimen corrosion rates under dynamic and static conditions.

  10. Design and performance of recirculating systems for Atlantic salmon (Salmo salar) at the USDA ARS National Cold Water Marine Aquaculture Center (Franklin, Maine)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Atlantic salmon cultured in the NCWMAC breeding program have grown well in the fish culture systems during the first 3 years of operation. The systems were operated at approximately 98% reuse (2% makeup water on the basis of flow rate). The water recirculating systems maintained acceptable water qua...

  11. A nitrogen budget for a closed, recirculating mariculture system

    Microsoft Academic Search

    Eric S. Thoman; Ellery D. Ingall; D. Allen Davis; Connie R. Arnold

    2001-01-01

    Nitrogen dynamics were evaluated in a closed, recirculating mariculture system by constructing a mass and isotopic balance of all major nitrogen pools. The experimental system consisted of 12?238-l, closed, independent, recirculating systems, each containing red drum (Sciaenopsocellatus), a biological filter, water pump and subsurface aeration. The standard system used in our laboratory was compared to two treatments in order to

  12. Fixed-biofilm reactors applied to waste water treatment and aquacultural water recirculating systems

    Microsoft Academic Search

    J. Bovendeur

    1989-01-01

    Fixed-biofilm waste water treatment may be regarded as one of the oldest engineered biological waste water treatment methods. With the recent introduction of modern packing materials, this type of reactor has received a renewed impuls for implementation in a wide field of water treatment.In this thesis the possibilities are presented for fixed-film post-treatment of anaerobically digested domestic sewage and water

  13. Control of biological growth in recirculating cooling systems using treated secondary effluent as makeup water with monochloramine.

    PubMed

    Chien, Shih-Hsiang; Chowdhury, Indranil; Hsieh, Ming-Kai; Li, Heng; Dzombak, David A; Vidic, Radisav D

    2012-12-01

    Secondary-treated municipal wastewater, an abundant and widely distributed impaired water source, is a promising alternative water source for thermoelectric power plant cooling. However, excessive biological growth is a major challenge associated with wastewater reuse in cooling systems as it can interfere with normal system operation as well as enhance corrosion and scaling problems. Furthermore, possible emission of biological aerosols (e.g., Legionella pneumophila) with the cooling tower drift can lead to public health concerns within the zone of aerosol deposition. In this study, the effectiveness of pre-formed and in-situ-formed monochloramine was evaluated for its ability to control biological growth in recirculating cooling systems using secondary-treated municipal wastewater as the only makeup water source. Bench-scale studies were compared with pilot-scale studies for their ability to predict system behavior under realistic process conditions. Effectiveness of the continuous addition of pre-formed monochloramine and monochloramine formed in-situ through the reaction of free chlorine with ammonia in the incoming water was evaluated in terms of biocide residual and its ability to control both planktonic and sessile microbial populations. Results revealed that monochloramine can effectively control biofouling in cooling systems employing secondary-treated municipal wastewater and has advantages relative to use of free chlorine, but that bench-scale studies seriously underestimate biocide dose and residual requirements for proper control of biological growth in full-scale systems. Pre-formed monochloramine offered longer residence time and more reliable performance than in-situ-formed monochloramine due to highly variable ammonia concentration in the recirculating water caused by ammonia stripping in the cooling tower. Pilot-scale tests revealed that much lower dosing rate was required to maintain similar total chlorine residual when pre-formed monochloramine was used as compared to in-situ-formed monochloramine. Adjustment of biocide dose to maintain monochloramine residual above 3mg/L is needed to achieve successful biological growth control in recirculating cooling systems using secondary-treated municipal effluent as the only source of makeup water. PMID:23063442

  14. A model for predicting the quantities of dissolved inorganic nitrogen released in effluents from a sea bass ( Dicentrarchus labrax) recirculating water system

    Microsoft Academic Search

    Pascal Pagand; Jean Paul Blancheton; Claude Casellas

    2000-01-01

    Fish excretions and the transformation of nitrogen by bacteria in the nitrifying biofilter are two of the main sources of dissolved inorganic nitrogen (DIN) in fish farms that use recirculating water systems. In this study, the DIN concentration in an experimental Dicentrarchus labrax aquaculture system was calculated using empirical sub-models for fish growth, ingested food and water replacement. The specific

  15. Particle size distribution and removal efficiency for three types of clarifiers in a warm-water, low-salinity, recirculating aquaculture system for juvenile red drum culture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recirculating aquaculture systems offer a solution to declining natural finfish stocks while limiting nutrient outputs and eutrophication of effluent waters. Because water is reused in these systems, the solids must be efficiently removed by mechanical treatment devices otherwise the solids buildup...

  16. A low energy, bio-secure, 'hybrid' recirculation system incorporating air lift pumps for water circulation, aeration, and CO2 degassing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A ‘Hybrid’ recirculating aquaculture system design utilizes elements of both a ‘Centralized’ design concept with a single water treatment system for a number of fish tanks and the ‘Modular’ design concept which employs a individual treatment system for each fish culture tank. The ‘Hybrid’ recirculat...

  17. Effects of elevated atmospheric carbon dioxide concentrations on water and acid requirements of soybeans grown in a recirculating hydroponic system

    NASA Technical Reports Server (NTRS)

    Mackowiak, C. L.; Wheeler, R. M.; Lowery, W.; Sager, J. C.

    1990-01-01

    Establishing mass budgets of various crop needs, i.e. water and nutrients, in different environments is essential for the Controlled Ecological Life Support System (CELSS). The effects of CO2 (500 and 1000 umol mol (exp -1)) on water and acid use (for pH control) by soybeans in a recirculating hydroponic system were examined. Plants of cvs. McCall and Pixie were grown for 90 days using the nutrient film technique (NFT) and a nitrate based nutrient solution. System acid use for both CO2 levels peaked near 4 weeks during a phase of rapid vegetative growth, but acid use decreased more rapidly under 500 compared to 1000 umol mol (exp GR) CO2. Total system water use by 500 and 1000 umol mol (exp -1) plants was similar, leaving off at 5 weeks and declining as plants senesced (ca. 9 weeks). However, single leaf transpiration rates were consistently lower at 1000 umol mol (exp -1). The data suggest that high CO2 concentrations increase system acid (and nutrient) use because of increased vegetative growth, which in turn negates the benefit of reduced water use (lower transpiration rates) per unit leaf area.

  18. EFFECTS OF WATER RECIRCULATION ON WATER QUALITY AND BOTTOM SOIL IN AQUACULTURE PONDS

    Microsoft Academic Search

    Oscar Zelaya; Claude E. Boyd; David R. Teichert-Coddington; Bartholomew W. Green

    There is considerable interest in reducing negative environmental impacts of shrimp and fish farming. One of the most promising methods for reducing the environmental effects of pond aquaculture is to use water-recirculating systems to minimize effluents. However, few studies have been performed to evaluate the effect of recirculation upon soil and water quality in ponds. This study evaluates changes in

  19. Fuel cell cooling and recirculation system

    SciTech Connect

    Dighe, S.V.

    1982-12-07

    Method and apparatus for cooling and recirculating oxidant to the cathode of a fuel cell stack. Heat energy is removed from the fuel cell stack through utilization of excess air or other oxidant relative to the stoichiometric amount for reaction with a hydrogen-containing fuel. Reaction products, including excess air and water, flow to a nozzle upstream of a flow constricting venturi. A coolant, such as liquid water in a fine spray form, is injected through the venturi and draws the reaction products through the venturi. The mixing of the coolant and the reaction products results in a condensation of the high temperature reaction product water vapor and further dehumidification of the reaction products takes place in a passive separator such as a demister. Coolant is injected into the venturi in sufficient quantity to develop the pressure head necessary to recirculate the cooled and dehumidified air through a conduit system and back to the fuel cell stack. A supply of makeup air is also provided. Coolant and water collected in the passive separator can also be recirculated for injection through the venturi.

  20. Future of recirculating systems in the US aquaculture industry

    SciTech Connect

    Malone, R.F.

    1994-08-01

    Recirculating systems consist of a culture unit, a recirculating pump, and a treatment block which facilitate extended re-use of water in the rearing of aquatic animals. As water re-use is extended from a few hours to months or even years, the complexity of the treatment block increases. Classified as either `open` with greater than 10 percent water replacement per day or `closed` with less than 10 percent daily replacement, most recirculating systems include aerators, clarifiers, and biofilters as key core elements. The aquaculture industry is increasingly facing a variety of socio-economic issues which will dramatically influence its future development. These problems range from increased competition for water rights through price depression and foreign imports to predation by protected migratory birds. As water-use, environmental, and conservation conflicts grow, the cost differences between the flow-through and closed production technologies will narrow, increasing the industry`s use of recirculating systems.

  1. Low-head saltwater recirculating aquaculture systems utilized for juvenile red drum production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recirculating aquaculture systems reuse water with mechanical and biological treatment between each use and thus require wastewater treatment techniques for continuous waste removal. However, the traditional techniques and equipment utilized in recirculating aquaculture systems are expensive. The d...

  2. Effect of copper on the growth of shrimps Litopenaeus vannamei: water parameters and copper budget in a recirculating system

    NASA Astrophysics Data System (ADS)

    Cheng, Bo; Liu, Ying; Yang, Hongsheng; Song, Yi; Li, Xian

    2014-09-01

    Shrimps ( Litopenaeus vannamei) were intensively cultured in a recirculating aquaculture system for 98 days to investigate effects of 0.3 mg/L Cu on its performance, Cu budget, and Cu distribution. Shrimps in Cu-treated systems had greater mean final weight (11.10 vs 10.50 g), body length (107.23 vs 106.42 mm), survival rate (67.80% vs 66.40%), and yield (6.42 vs 5.99 kg/m3), and lower feed conversion ratio (1.20 vs 1.29) than those in control systems but the differences were not significant. Vibrio numbers remained stable (104-106 colony forming units/mL) in the rearing tanks of both control and treated systems. Total ammonium-N, nitrite-N, nitrate-N, pH, chemical oxygen demand, 5-day carbonaceous biochemical oxygen demand, and total suspended solids were similar in controls and treatments. Dissolved Cu concentration in the treated systems decreased from 0.284 to 0.089 mg/L while in the control systems it increased from 0.006 2 to 0.018 mg/L. The main sources of Cu in the treated systems were the artificially added component (75.7% of total input), shrimp feed (21.0%), water (2.06%), and shrimp biomass (1.22%). The major outputs of Cu occurred via the mechanical filter (41.7%), water renewal (15.6%), and draining of the sediment trap (15.1%). The foam fractionator removed only 0.69% of total Cu input. Harvested shrimp biomass accounted for 11.68% of Cu input. The Cu concentration of shrimps in the Cu-treated systems (30.70 mg/kg wet weight) was significantly higher than that in control systems (22.02 mg/kg). Both were below the maximum permissible concentration (50 mg/kg) for Cu in seafood for human consumption in China. Therefore, recirculating systems can be used for commercial on-growing of Litopenaeus vannamei without loss of shrimp quality, even in water polluted by 0.30 mg/L Cu. The mechanical filter is the main route for Cu removal.

  3. Flavobacterium branchiophilum and F. succinicans associated with bacterial gill disease in rainbow trout Oncorhynchus mykiss (Walbaum) in water recirculation aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Raised rainbow trout Oncorhynchus mykiss in six replicated water recirculation aquaculture systems (WRAS), and manipulated environmental conditions to promote bacterial gill disease (BGD). For each episode of BGD, gill tissue was sampling from affected fish, unaffected fish within the same WRAS, and...

  4. Comparing the effects of high vs. low nitrate on the health, performance, and welfare of juvenile rainbow trout Oncorhynchus mykiss within water recirculating aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous research indicates that rainbow trout (Oncorhynchus mykiss) begin to exhibit health and welfare problems when cultured within water recirculating aquaculture systems (WRAS) operated at low exchange (6.7 days hydraulic retention time) and a mean feed loading rate of 4.1 kg feed/m3 daily make...

  5. The effects of carbon dioxide on performance and histopathology of rainbow trout Oncorhynchus mykiss in water recirculation aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chronic exposure to elevated levels of dissolved carbon dioxide (CO2) has been linked to reduced growth, physiological disturbances and negative health outcomes in intensively reared fish. Although pumping to a degassing tower can lower concentrations of dissolved CO2 in water recirculation aquacult...

  6. Use of Produced Water in Recirculated Cooling Systems at Power Generating Facilities

    SciTech Connect

    C. McGowin; M. DiFilippo; L. Weintraub

    2006-06-30

    Tree ring studies indicate that, for the greater part of the last three decades, New Mexico has been relatively 'wet' compared to the long-term historical norm. However, during the last several years, New Mexico has experienced a severe drought. Some researchers are predicting a return of very dry weather over the next 30 to 40 years. Concern over the drought has spurred interest in evaluating the use of otherwise unusable saline waters to supplement current fresh water supplies for power plant operation and cooling and other uses. The U.S. Department of Energy's National Energy Technology Laboratory sponsored three related assessments of water supplies in the San Juan Basin area of the four-corner intersection of Utah, Colorado, Arizona, and New Mexico. These were (1) an assessment of using water produced with oil and gas as a supplemental supply for the San Juan Generating Station (SJGS); (2) a field evaluation of the wet-surface air cooling (WSAC) system at SJGS; and (3) the development of a ZeroNet systems analysis module and an application of the Watershed Risk Management Framework (WARMF) to evaluate a range of water shortage management plans. The study of the possible use of produced water at SJGS showed that produce water must be treated to justify its use in any reasonable quantity at SJGS. The study identified produced water volume and quality, the infrastructure needed to deliver it to SJGS, treatment requirements, and delivery and treatment economics. A number of produced water treatment alternatives that use off-the-shelf technology were evaluated along with the equipment needed for water treatment at SJGS. Wet surface air-cooling (WSAC) technology was tested at the San Juan Generating Station (SJGS) to determine its capacity to cool power plant circulating water using degraded water. WSAC is a commercial cooling technology and has been used for many years to cool and/or condense process fluids. The purpose of the pilot test was to determine if WSAC technology could cool process water at cycles of concentration considered highly scale forming for mechanical draft cooling towers. At the completion of testing, there was no visible scale on the heat transfer surfaces and cooling was sustained throughout the test period. The application of the WARMF decision framework to the San Juan Basis showed that drought and increased temperature impact water availability for all sectors (agriculture, energy, municipal, industry) and lead to critical shortages. WARMF-ZeroNet, as part of the integrated ZeroNet decision support system, offers stakeholders an integrated approach to long-term water management that balances competing needs of existing water users and economic growth under the constraints of limited supply and potential climate change.

  7. Denitrification in recirculating systems: Theory and applications

    Microsoft Academic Search

    Jaap van Rijn; Yossi Tal; Harold J. Schreier

    2006-01-01

    Profitability of recirculating systems depends in part on the ability to manage nutrient wastes. Nitrogenous wastes in these systems can be eliminated through nitrifying and denitrifying biofilters. While nitrifying filters are incorporated in most recirculating systems according to well-established protocols, denitrifying filters are still under development. By means of denitrification, oxidized inorganic nitrogen compounds, such as nitrite and nitrate are

  8. Water treatment and waste characterization evaluation of an intensive recirculating fish production system

    Microsoft Academic Search

    Joanna G. Twarowska; Philip W. Westerman; Thomas M. Losordo

    1997-01-01

    A combination of two different technologies used for fish production was evaluated at the North Carolina State University (NCSU) F?ish Barn facility. The combined system included the ECOFISH? tank, developed at the Norwegian Hydrotechnical Laboratory (NHL) at SINTEF (Trondheim, Norway) and water treatment and recycle technology designed at NCSU. Approximately 2170 fingerling tilapia (Oreochromis niloticus, Oreochromis niloticus × Oreochromis aureus)

  9. Water and Energy Savings using Demand Hot Water Recirculating Systems in Residential Homes: A Case Study of Five Homes in Palo Alto, California

    SciTech Connect

    Ally, M.R.

    2002-11-14

    This report summarizes a preliminary study aimed at estimating the potential of saving potable water, (and the electrical energy used to heat it), that is presently lost directly to the drain while occupants wait for hot water to arrive at the faucet (point of use). Data were collected from five single-family homes in Palo Alto, California. Despite the small sample size in this study, the results make a compelling case for retrofitting homes with hot water recirculation systems to eliminate unnecessary wastage of water at the point of use. Technical as well as behavioral and attitudinal changes towards water conservation are necessary for a fulfilling and successful conservation effort. This report focuses on the technical issues, but behavioral issues are also noted, which may be factored into future studies involving local and state governments and utility companies.

  10. An application of membrane inlet mass spectrometry to measure denitrification in a recirculating mariculture system

    Microsoft Academic Search

    Mark J McCarthy; Wayne S Gardner

    2003-01-01

    The detrimental effects of aquaculture waste discharges require development of recirculating and\\/or pretreatment systems. Denitrification, in combination with nitrification, removes fixed nitrogen from culture water in recirculating systems. Three experiments were conducted to measure denitrification rates in biofilter media (“bioballs”) and sediments from a recirculating mariculture system. In this case, “sediments” refer to solids accumulated at the bottom of the

  11. Comparing the effects of feeding a grain- or a fish meal-based diet on water quality, waste production, and rainbow trout Oncorhynchus mykiss performance within low exchange water recirculating aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Feeding a fish meal-free grain-based diet (GB) was compared to feeding a fish meal-based diet (FM) relative to water quality criteria, waste production, water treatment process performance, and rainbow trout Oncorhynchus mykiss performance within six replicated water recirculating aquaculture system...

  12. USE OF PRODUCED WATER IN RECIRCULATING COOLING SYSTEMS AT POWER GENERATING FACILITIES

    SciTech Connect

    Michael N. DiFilippo

    2004-08-01

    The purpose of this study is to evaluate produced water as a supplemental source of water for the San Juan Generating Station (SJGS). This study incorporates elements that identify produced water volume and quality, infrastructure to deliver it to SJGS, treatment requirements to use it at the plant, delivery and treatment economics, etc. SJGS, which is operated by Public Service of New Mexico (PNM) is located about 15 miles northwest of Farmington, New Mexico. It has four units with a total generating capacity of about 1,800 MW. The plant uses 22,400 acre-feet of water per year from the San Juan River with most of its demand resulting from cooling tower make-up. The plant is a zero liquid discharge facility and, as such, is well practiced in efficient water use and reuse. For the past few years, New Mexico has been suffering from a severe drought. Climate researchers are predicting the return of very dry weather over the next 30 to 40 years. Concern over the drought has spurred interest in evaluating the use of otherwise unusable saline waters. Deliverable 1 presents a general assessment of produced water generation in the San Juan Basin in Four Corners Area of New Mexico. Oil and gas production, produced water handling and disposal, and produced water quantities and chemistry are discussed. Legislative efforts to enable the use of this water at SJGS are also described.

  13. USE OF PRODUCED WATER IN RECIRCULATING COOLING SYSTEMS AT POWER GENERATING FACILITIES

    SciTech Connect

    Michael N. DiFilippo

    2004-08-01

    The purpose of this study is to evaluate produced water as a supplemental source of water for the San Juan Generating Station (SJGS). This study incorporates elements that identify produced water volume and quality, infrastructure to deliver it to SJGS, treatment requirements to use it at the plant, delivery and treatment economics, etc. SJGS, which is operated by Public Service of New Mexico (PNM) is located about 15 miles northwest of Farmington, New Mexico. It has four units with a total generating capacity of about 1,800 MW. The plant uses 22,400 acre-feet of water per year from the San Juan River with most of its demand resulting from cooling tower make-up. The plant is a zero liquid discharge facility and, as such, is well practiced in efficient water use and reuse. For the past few years, New Mexico has been suffering from a severe drought. Climate researchers are predicting the return of very dry weather over the next 30 to 40 years. Concern over the drought has spurred interest in evaluating the use of otherwise unusable saline waters. Deliverable 2 focuses on transportation--the largest obstacle to produced water reuse in the San Juan Basin (the Basin). Most of the produced water in the Basin is stored in tanks at the well head and must be transported by truck to salt water disposal (SWD) facilities prior to injection. Produced water transportation requirements from the well head to SJGS and the availability of existing infrastructure to transport the water are discussed in this deliverable.

  14. USE OF PRODUCED WATER IN RECIRCULATING COOLING SYSTEMS AT POWER GENERATING FACILITIES

    SciTech Connect

    Kent Zammit; Michael N. DiFilippo

    2005-01-01

    The purpose of this study is to evaluate produced water as a supplemental source of water for the San Juan Generating Station (SJGS). This study incorporates elements that identify produced water volume and quality, infrastructure to deliver it to SJGS, treatment requirements to use it at the plant, delivery and treatment economics, etc. SJGS, which is operated by Public Service of New Mexico (PNM) is located about 15 miles northwest of Farmington, New Mexico. It has four units with a total generating capacity of about 1,800 MW. The plant uses 22,400 acre-feet of water per year from the San Juan River with most of its demand resulting from cooling tower make-up. The plant is a zero liquid discharge facility and, as such, is well practiced in efficient water use and reuse. For the past few years, New Mexico has been suffering from a severe drought. Climate researchers are predicting the return of very dry weather over the next 30 to 40 years. Concern over the drought has spurred interest in evaluating the use of otherwise unusable saline waters. Produced water is generated nationally as a byproduct of oil and gas production. Seven states generate 90 percent of the produced water in the continental US. About 37 percent of the sources documented in the US Geological Survey's (USGS) Produced Waters Database have a TDS of less than 30,000 mg/l. This is significant because produced water treatment for reuse in power plants was found to be very costly above 30,000 mg/l TDS. For the purposes of this report, produced water treatment was assessed using the technologies evaluated for the San Juan Generating Station (SJGS) in Deliverable 3, Treatment and Disposal Analysis. Also, a methodology was developed to readily estimate capital and operating costs for produced water treatment. Two examples are presented to show how the cost estimating methodology can be used to evaluate the cost of treatment of produced water at power plants close to oil and gas production.

  15. HEXACHLOROBENZENE UPTAKE BY FATHEAD MINNOWS AND MACRO INVERTEBRATES IN RECIRCULATING SEDIMENT/WATER SYSTEMS

    EPA Science Inventory

    Fathead minnow (Pimephales promelas), the worm, Lumbriculus variegatus, and the amphipods Hyalella azteca and Gammarus lacustris were exposed to hexachlorobenzene (HCB) in water with and without a bed of HCB-spiked sediment. ater HCB concentrations were maintained by recirculatio...

  16. Use of floating bead filters to recondition recirculating waters in warmwater aquaculture production systems

    Microsoft Academic Search

    Ronald F Malone; Lance E Beecher

    2000-01-01

    Floating bead filters (FBFs) are expandable granular filters that display a bioclarification behavior similar to sand filters. They function as a physical filtration device (or clarifier) by removing solids, while simultaneously encouraging the growth of bacteria that remove dissolved wastes from the water through biofiltration processes. Presently, there are two classes of FBFs that exist. Hydraulic and air washed units

  17. Performance of Water Recirculation Loop Maintenance Components for the Advanced Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Rector, Tony; Peyton, Barbara M.; Steele, John W.; Makinen, Janice; Bue, Grant C.; Campbell, Colin

    2014-01-01

    Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a recirculating control loop which had no water quality maintenance. Results show that periodic water maintenance can improve performance of the SWME. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage of this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing sublimator technology. The driver for the evaluation of water recirculation maintenance components was to enhance the robustness of the SWME through the leveraging of fluid loop management lessons learned from the International Space Station (ISS). A patented bed design that was developed for a United Technologies Aerospace System military application provided a low pressure drop means for water maintenance in the SWME recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for the ISS to introduce a biocide in a microgravity compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  18. A Low-Cost Recirculation System Using Disposable Beverage Containers

    Microsoft Academic Search

    Mark C. Bates; Terrence R. Tiersch

    1995-01-01

    A tank system with recirculating water designed for use with disposable plastic 3-L beverage bottles is described. The system consisted of 100 culture units (2-L working volume in each), five 40-L tanks, and an upwelling biofilter. The 40-L tanks were used to increase the total volume of the system, to allow operation of the filter when bottles were not occupied,

  19. Design, loading, and water quality in recirculating systems for low salinity finfish species at the USDA /ARS Sustainable Marine Aquaculture Systems facility (Fort Pierce, FL)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The USDA ARS Sustainable Marine Aquaculture System Facility was established by the USDA ARS in collaboration with Harbor Branch Oceanographic Institute / Florida Atlantic University to improve the efficiency and sustainability of inland warmwater marine fish culture in recirculating aquaculture syst...

  20. Turbocharged engine exhaust gas recirculation system

    SciTech Connect

    Stachowicz, R.W.

    1984-01-24

    Improved exhaust gas recirculation systems for turbocharged gas engines that include an exhaust pipe, a turbocharger connected thereto, and a carburetor connected with a source of gas for the engine. The recirculation system includes an air conduit extending from the turbocharger compressor discharge to a venturi, an exhaust gas conduit that extends from a connection with the exhaust pipe between the engine and the turbocharger to the venturi, a second air conduit that extends from the exhaust pipe to a connection with the first air conduit, and control valves located in the exhaust gas conduit and in the second air conduit. The valves are closed when the engine is being started or idling at no load and open when a load is imposed or when engine rpm's are increased. No pumps, blowers, etc. are needed because the system operates on a differential in pressure created within the system to cause the exhaust gas recirculation.

  1. Rating fixed film nitrifying biofilters used in recirculating aquaculture systems

    Microsoft Academic Search

    Ronald F. Malone; Timothy J. Pfeiffer

    2006-01-01

    Predicting the performance of biofilters is an engineering challenge that is critical to both designers and managers. The task is complicated by the wide variety of water quality expectations and environmental conditions displayed by a recirculating aquaculture system (RAS). A myriad of biofilters designs have been generated reflecting approaches of engineers attempting to maximize specific surface area and oxygen transfer

  2. A recirculating seawater aquarium system for inland laboratories

    Microsoft Academic Search

    M. E. Lickey; R. L. Emigh; F. R. Randle

    1970-01-01

    We have designed and installed a 7,500 l recirculating aquarium system for the purpose of maintaining marine gastropods in an inland laboratory. It is completely nonmetallic and can be adapted for any number of isolated living compartments. Vonvenient and efficient filtration is achieved by the use of disposable cartridge filters. The water temperature is regulated by a direct expansion cooling

  3. The potential use of constructed wetlands in a recirculating aquaculture system for shrimp culture

    Microsoft Academic Search

    Ying-Feng Lin; Shuh-Ren Jing; Der-Yuan Lee

    2003-01-01

    A pilot-scale constructed wetland unit, consisting of free water surface (FWS) and subsurface flow (SF) constructed wetlands arranged in series, was integrated into an outdoor recirculating aquaculture system (RAS) for culturing Pacific white shrimp (Litopenaeus vannamei). This study evaluated the performance of the wetland unit in treating the recirculating wastewater and examined the effect of improvement in water quality of

  4. Membrane biological reactor treatment of a saline backwash flow from a recirculating aquaculture system

    Microsoft Academic Search

    Mark J. Sharrer; Yossi Tal; Drew Ferrier; Joseph A. Hankins; Steven T. Summerfelt

    2007-01-01

    A recirculating aquaculture system (RAS) can minimize water use, allowing fish production in regions where water is scarce and also placing the waterborne wastes into a concentrated and relatively small volume of effluent. The RAS effluent generated during clarifier backwash is usually small in volume (possibly 0.2–0.5% of the total recirculating flow when microscreen filters are used) but contains high

  5. Fish Health Management Considerations in Recirculating Aquaculture Systems -Part 2: Pathogens1

    E-print Network

    Watson, Craig A.

    Cir 121 Fish Health Management Considerations in Recirculating Aquaculture Systems - Part 2 Aquaculture Laboratory, Ruskin FL 33570, Program in Fisheries and Aquatic Sciences, School of Forest Resources Introduction Recirculating aquaculture systems, also known as water reuse systems, have become more and more

  6. Performance of Water Recirculation Loop Maintentance Components for the Advanced Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Rector, Tony; Peyton, Barbara; Steele, John W.; Bue, Grant C.; Campbell, Colin; Makinen, Janice

    2014-01-01

    Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessonslearned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  7. Performance of Water Recirculation Loop Maintenance Components for the Advanced Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Rector, Tony; Peyton, Barbara M.; Steele, John W.; Makinen, Janice; Bue, Grant C.; Campbell, Colin

    2014-01-01

    Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessons learned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  8. Developments in recirculating systems for Arctic char culture in North America

    Microsoft Academic Search

    Steven T. Summerfelt; Gary Wilton; David Roberts; Tina Rimmerd; Kari Fonkalsrud

    2004-01-01

    Arctic char (Salvelinus alpinus) tolerate high-density culture conditions, have an excellent fillet yield, are amenable to niche marketing, and are suitable for production within super-intensive recirculating systems. Much of the North American production of Arctic char has been within recirculating systems, which can provide more optimum water temperatures for fish growth and can also overcome limitations created by a lack

  9. The evaluation of oxygen and carbon dioxide transfer associated with airlifts in recirculating aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Airlifts in recirculating aquaculture systems (RAS) provide aeration, degasification, and water circulation. They allow the simplification of systems, and if designed properly, can reduce the capital costs and minimize operation and maintenance associated with alternative pumping systems. In order t...

  10. Preoperational test report, recirculation ventilation systems

    SciTech Connect

    Clifton, F.T.

    1997-11-11

    This represents a preoperational test report for Recirculation Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102 and supports the ability to exhaust air from each tank. Each system consists of a valved piping loop, a fan, condenser, and moisture separator; equipment is located inside each respective tank farm in its own hardened building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  11. Integrated Dynamic Aquaculture and Wastewater Treatment Modelling for Recirculating Aquaculture Systems

    Microsoft Academic Search

    Torsten E. I. Wika; Bjorn T. Lind

    Recirculating aquaculture systems (RAS) in land based sh tanks, where the sh tank euen t is biologically treated and then recirculated back to the sh tanks, of- fers a possibility for large scale ecologically sustainable sh production. In order to fully exploit the advantages of RAS, however, the water exchange should be as small as possible. This implies strong demands

  12. Integrated dynamic aquaculture and wastewater treatment modelling for recirculating aquaculture systems

    Microsoft Academic Search

    Torsten E. I. Wik; Björn T. Lindén; Per I. Wramner

    2009-01-01

    Recirculating aquaculture systems (RAS) in land based fish tanks, where the fish tank effluent is biologically treated and then recirculated back to the fish tanks, offers a possibility for large scale ecologically sustainable fish production. In order to fully exploit the advantages of RAS, however, the water exchange should be as small as possible. This implies strong demands on the

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

    SciTech Connect

    David Dzombak; Radisav Vidic; Amy Landis

    2012-06-30

    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 tertiary 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

  14. Pressure transducer for exhaust gas recirculation system

    SciTech Connect

    Bradshaw, C.E.

    1983-02-15

    A pressure transducer for use in internal combustion engine exhaust gas recirculation systems is disclosed having low inertia moving components for improved response time and a low cost diaphragm mounting arrangement. Upper and lower housing shells define in cooperation with a diaphragm and an upperand lower reaction plates fabricated from light weight plastic, a vacuum chamber, control chamber and a vent chamber. The single diaphragm is connected to the inner wall of the housing by a clamping ring, thereby dividing the diaphragm into individually pressure responsive upper and lower portions.

  15. Exhaust gas recirculation system for an internal combustion engine

    DOEpatents

    Wu, Ko-Jen

    2013-05-21

    An exhaust gas recirculation system for an internal combustion engine comprises an exhaust driven turbocharger having a low pressure turbine outlet in fluid communication with an exhaust gas conduit. The turbocharger also includes a low pressure compressor intake and a high pressure compressor outlet in communication with an intake air conduit. An exhaust gas recirculation conduit fluidly communicates with the exhaust gas conduit to divert a portion of exhaust gas to a low pressure exhaust gas recirculation branch extending between the exhaust gas recirculation conduit and an engine intake system for delivery of exhaust gas thereto. A high pressure exhaust gas recirculation branch extends between the exhaust gas recirculation conduit and the compressor intake and delivers exhaust gas to the compressor for mixing with a compressed intake charge for delivery to the intake system.

  16. Principles of Water Recirculation and Filtration in Aquaculture 1

    E-print Network

    Watson, Craig A.

    FA12 Principles of Water Recirculation and Filtration in Aquaculture 1 Michael McGee and Charles) removal of particulate matter, 3) biological filtration to remove waste ammonia and nitrite, and 4 and Filtration in Aquaculture 2 Removal of particulate matter Solids resulting from fish waste and uneaten feed

  17. Design and performance characteristics of a low-head recirculating aquaculture tank system for low salinity finfish production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water treatment components of a recirculating aquaculture system (RAS) consist mainly of: solid removal devices, biofiltration, aeration, degassing units, and water distribution. For each component, multiple options are available and the selection is based on system volume, system hydrodynamics, fis...

  18. Flow, aeration, and carbon dioxide transfer rates for airlifts used in recirculating aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Airlift pumping systems reduce the electrical costs of moving water in a recirculating aquaculture system and can be concurrently designed to aerate water and remove carbon dioxide. This study determined the water flow, oxygen transfer, and CO2 removal rates for water using airlift technology in a 1...

  19. Process requirements for achieving full-flow disinfection of recirculating water using ozonation and UV irradiation

    Microsoft Academic Search

    Steven T. Summerfelt; Mark J. Sharrer; Scott M. Tsukuda; Michael Gearheart

    2009-01-01

    A continuous water disinfection process can be used to prevent the introduction and accumulation of obligate and opportunistic fish pathogens in recirculating aquaculture systems (RAS), especially during a disease outbreak when the causative agent would otherwise proliferate within the system. To proactively prevent the accumulation of fish pathogens, ozonation and ultraviolet (UV) irradiation processes have been used separately or in

  20. Process Requirements for Achieving Full-Flow Disinfection of Recirculating Water Using Ozonation and UV Irradiation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A continuous water disinfection process can be used to prevent the introduction and accumulation of obligate and opportunistic fish pathogens in recirculating aquaculture systems (RAS), especially during a disease outbreak when the causative agent would otherwise proliferate within the system. To p...

  1. Kinetics of electro-oxidation of ammonia-N, nitrites and COD from a recirculating aquaculture saline water system using BDD anodes

    Microsoft Academic Search

    V. Díaz; R. Ibáñez; P. Gómez; A. M. Urtiaga; I. Ortiz

    2011-01-01

    The viability of the electro-oxidation technology provided with boron doped diamond (BDD) electrodes for the treatment and reuse of the seawater used in a Recirculating Aquaculture System (RAS) was evaluated in this work.The influence of the applied current density (5–50 A m?2) in the removal of Total Ammonia Nitrogen (TAN), nitrite and chemical oxygen demand (COD) was analyzed observing that complete TAN

  2. Distribution of Off-Flavor Compounds and Isolation of Geosmin-Producing Bacteria in a Series of Water Recirculating Systems for Rainbow Trout Culture

    Microsoft Academic Search

    Kevin K. Schrader; Steven T. Summerfelt

    2010-01-01

    Preharvest off-flavor in aquaculture products results in large economic losses to producers due to delayed harvest. The common off flavors “earthy” and “musty” are due to the presence of geosmin and 2-methylisoborneol (MIB), respectively. Although certain species of cyanobacteria are responsible for these problems in pond-cultured fish, the microbial sources of geosmin and MIB in recirculating aquaculture systems (RASs) are

  3. Internal combustion engine with an exhaust gas recirculation system

    SciTech Connect

    Saiki, J.

    1980-03-25

    Disclosed is an internal combustion engine with an exhaust gas recirculation system. The engine is provided with a carburetor which includes a primary system and a secondary system. The recirculated exhaust gas is supplied to the intake passage via an exhaust gas supply pipe which is disposed at a position downstream of the carburetor. The top end of the exhaust gas supply pipe is open at a space having a predetermined positional relationship with the wall of the primary system.

  4. Recirculating systems for Atlantic salmon (Salmo salar) at the USDA ARS National Cold Water Marine Aquaculture Center (Franklin, Maine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Northeastern U.S has the ideal location and unique opportunity to be a leader in cold-water marine finfish aquaculture. However, problems and regulations on environmental issues, mandatory stocking of 100 percent native North American salmon, and disease have impacted economic viability of the U...

  5. Continuous hydroponic wheat production using a recirculating system

    NASA Technical Reports Server (NTRS)

    Mackowiak, C. L.; Owens, L. P.; Hinkle, C. R.; Prince, R. P.

    1989-01-01

    Continuous crop production, where plants of various ages are growing simultaneously in a single recirculating nutrient solution, is a possible alternative to batch production in a Controlled Ecological Life Support System. A study was conducted at John F. Kennedy Space Center where 8 trays (0.24 sq m per tray) of Triticum aestivum L. Yecora Rojo were grown simultaneously in a growth chamber at 23 C, 65 percent relative humidity, 1000 ppm CO2, continuous light, with a continuous flow, thin film nutrient delivery system. The same modified Hoagland nutrient solution was recirculated through the plant trays from an 80 L reservoir throughout the study. It was maintained by periodic addition of water and nutrients based on chemical analyses of the solution. The study was conducted for 216 days, during which 24 trays of wheat were consecutively planted (one every 9 days), 16 of which were grown to maturity and harvested. The remaining 8 trays were harvested on day 216. Grain yields averaged 520 g m(exp -2), and had an average edible biomass of 32 percent. Consecutive yields were unaffected by nutrient solution age. It was concluded that continual wheat production will work in this system over an extended period of time. Certain micronutrient deficiencies and toxicities posed problems and must be addressed in future continuous production systems.

  6. Performance of a Water Recirculation Loop Maintenance Device and Process for the Advanced Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Rector, Tony; Steele, John W.; Bue, Grant C.; Campbell, Colin; Makinen, Janice

    2012-01-01

    A water loop maintenance device and process to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop has been undergoing a performance evaluation. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the water recirculation maintenance device and process is to further enhance this advantage through the leveraging of fluid loop management lessons-learned from the International Space Station (ISS). A bed design that was developed for a Hamilton Sundstrand military application, and considered for a potential ISS application with the Urine Processor Assembly, provides a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance process further leverages a sorbent developed for ISS that introduces a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware. This

  7. Design and Evaluation of a Water Recirculation Loop Maintenance Device for the Advanced Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Steele, John W.; Rector, Tony; Bue, Grant C.; Campbell, Colin; Makinen, Janice

    2011-01-01

    A dual-bed device to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop has been designed and is undergoing testing. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the development of a water recirculation maintenance device is to further enhance this advantage through the leveraging of fluid loop management lessons-learned from the International Space Station (ISS). A bed design that was developed for a Hamilton Sundstrand military application, and considered for a potential ISS application with the Urine Processor Assembly, provides a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The bed design further leverages a sorbent developed for ISS that introduces a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a clear demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  8. The effect of feeding on oxygen consumption and ammonia excretion of juvenile tench Tinca tinca (L.) reared in a water recirculating system

    Microsoft Academic Search

    Zdzis?aw Zak??; Krystyna Demska-Zak??; Przemys?aw Jarocki; Konrad Stawecki

    2006-01-01

    The effect of feeding frequency (one, three, and continuous feeding), feed ration (0.2, 0.5, 0.8% of total fish biomass),\\u000a and feeding per se on the oxygen consumption (OC, mg O2 kg?1 h?1) and ammonia excretion (AE, mg TAN kg?1 h?1) of juvenile tench (body weight 15–19 g) and variations in these parameters in daily cycles were examined. Fish metabolism\\u000a was studied in a recirculating system

  9. Comparison of hydroponic crop production techniques in a recirculating fish culture system 

    E-print Network

    Wren, Steven Whitaker

    1984-01-01

    and usefulness for water treatment in a recirculating fish culture system. Both hydroponic techniques were incorporated into one recirculating ~Tile ia auras culture system to insure uniformity of hydroponic influent water. The hydroponic strategies were... and phosphate. They grew tomatoes and channel catfish. Each system had an 870 L fish tank followed by rotating disc biofilters, a 200 L settling tank, and hydroponic tanks, A flow rate of 10 L/minute led to a turnover rate of 1. 45 hours in the fish tanks...

  10. A study on the optimal hydraulic loading rate and plant ratios in recirculation aquaponic system

    Microsoft Academic Search

    Azizah Endut; A. Jusoh; N. Ali; W. B. Wan Nik; A. Hassan

    2010-01-01

    The growths of the African catfish (Clarias gariepinus) and water spinach (Ipomoea aquatica) were evaluated in recirculation aquaponic system (RAS). Fish production performance, plant growth and nutrient removal were measured and their dependence on hydraulic loading rate (HLR) was assessed. Fish production did not differ significantly between hydraulic loading rates. In contrast to the fish production, the water spinach yield

  11. Membrane biological reactor treatment of a saline backwash flow from a recirculating aquaculture system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A recirculating aquaculture system (RAS) can minimize water use, allowing fish production in regions where water is scarce and also placing the waterborne wastes into a concentrated and relatively small volume of effluent. The RAS effluent generated during clarifier backwash is usually small in vol...

  12. Application of airlift technology in recirculation aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marine hatcheries implementing recirculating aquaculture technology require pristine water quality and must be designed to provide a disease free environment as much as possible to limit disease transmission. Given the aggressive nature of a variety of marine pathogens, design considerations with re...

  13. The use of ozone in a high density recirculation system for rotifers

    Microsoft Academic Search

    G Suantika; P Dhert; G Rombaut; J Vandenberghe; T De Wolf; P Sorgeloos

    2001-01-01

    The use of ozone in the effluent treatment of a closed recirculation system for rotifers resulted in a significant improvement of rotifer production and water quality. Compared to a control treatment, the rotifer culture exposed to ozone did not only support a higher rotifer biomass (16000 vs. 8000 rotifers ml?1), it also allowed a prolongation of the culture period for

  14. Low-dose hydrogen peroxide application in closed recirculating aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of the present work was to simulate water treatment practice with hydrogen peroxide (HP) in recirculating aquaculture systems (RAS). Six identical 1700 L pilot scale RAS were divided into two experimental groups based on daily feed allocation and were operated under constant conditions durin...

  15. Design criteria for recirculating, marine ornamental production systems

    Microsoft Academic Search

    Craig A. Watson; Jeffrey E. Hill

    2006-01-01

    While recirculating aquaculture systems for food animals are well defined in the literature, little information is available for the emerging production of high value marine ornamental species. These organisms typically require systems which operate within a narrow range of parameters compared to most food animals, and in addition to growth and survival issues, individual appearance of animals is critical to

  16. Ozone Application in Recirculating Aquaculture System: An Overview

    Microsoft Academic Search

    Alex Augusto Gonçalves; Graham A. Gagnon

    2011-01-01

    In recirculating aquaculture systems (RAS), particulates (including feces, uneaten feed, bacteria, and algae) can cause several problems, in that they may harbor pathogens, can physically irritate the fish, and upon decomposition, release ammonia and consume oxygen. Mechanical filters, foam fractionators, and other engineered devices are used to remove particles quickly from aquaculture systems, in order to improve fish health and

  17. An Inexpensive Recirculating Aquaculture System with Multiple Use Capabilities.

    ERIC Educational Resources Information Center

    Scurlock, Gerald Don, Jr.; Cook, S. Bradford; Scurlock, Carrie Ann

    1999-01-01

    Describes the construction of an inexpensive recirculating aquaculture system that can hold up to 46 pounds of fish, invertebrates, and mussels for classroom use. The system is versatile, requires little maintenance, and can be used for both teaching and research purposes. (WRM)

  18. Recirculating Molten Metal Supply System And Method

    DOEpatents

    Kinosz, Michael J. (Apollo, PA); Meyer, Thomas N. (Murrysville, PA)

    2003-07-01

    The melter furnace includes a heating chamber (16), a pump chamber (18), a degassing chamber (20), and a filter chamber (22). The pump chamber (18) is located adjacent the heating chamber (16) and houses a molten metal pump (30). The degassing chamber (20) is located adjacent and in fluid communication with the pump chamber (18), and houses a degassing mechanism (36). The filter chamber (22) is located adjacent and in fluid communication with the degassing chamber (20). The filter chamber (22) includes a molten metal filter (38). The melter furnace (12) is used to supply molten metal to an externally located holder furnace (14), which then recirculates molten metal back to the melter furnace (12).

  19. New chemical removing and air cooling technology for clean room recirculation air using chilled pure water showering method

    Microsoft Academic Search

    H. Wakamatsu; M. Matsuki; N. Tanaka; Y. Iwanaga; K. Murata

    2001-01-01

    We have developed a new chemical removing and air cooling technique for clean room recirculation air using a gas-liquid contact method that consists of a combination of chilled pure water showering and optimum packing material. We have tested a new treatment system using this technique in an actual photolithography clean room finding many kinds of chemical contaminants of water-solubility substances

  20. Management Ability and the Economics of Recirculating Aquaculture Production Systems

    Microsoft Academic Search

    Richard F. Kazmierczak Jr.; Rex H. Caffey

    1995-01-01

    A bioeconomic model of fish growth in recirculating aquaculture systems was constructed by developing a bioenergetic model comprised of metabolic sub-models for growth, ammonia production, and oxygen consumption. Metabolite accumulations are determined by exogenous control variables for filtration and aeration and used to indirectly represent management ability. Numerical solutions to model parameters were obtained using a two point boundary shooting

  1. Anaerobic digestion of sludge from intensive recirculating aquaculture systems: Review

    Microsoft Academic Search

    Natella Mirzoyan; Yossi Tal; Amit Gross

    2010-01-01

    Intensive recirculating aquaculture systems (RAS) produce high volumes of biosolid waste which is a potential source of pollution if not properly treated. A reduction in sludge-mass would therefore minimize the potential environmental hazard and economic burden stemming from its disposal. Recently, anaerobic digestion was suggested as an alternative to aquaculture sludge digestion and stabilization in RAS. This practice results not

  2. Cooling water system design

    Microsoft Academic Search

    Jin-Kuk Kim; Robin Smith

    2001-01-01

    Research on cooling systems to date has focussed on the individual components of cooling systems, not the system as a whole. Cooling water systems should be designed and operated with consideration of all the cooling system components because of the interactions between cooling water networks and the cooling tower performance. In re-circulating cooling water systems, cooling water from the cooling

  3. Kinetics of electro-oxidation of ammonia-N, nitrites and COD from a recirculating aquaculture saline water system using BDD anodes.

    PubMed

    Díaz, V; Ibáñez, R; Gómez, P; Urtiaga, A M; Ortiz, I

    2011-01-01

    The viability of the electro-oxidation technology provided with boron doped diamond (BDD) electrodes for the treatment and reuse of the seawater used in a Recirculating Aquaculture System (RAS) was evaluated in this work. The influence of the applied current density (5-50 A m(-2)) in the removal of Total Ammonia Nitrogen (TAN), nitrite and chemical oxygen demand (COD) was analyzed observing that complete TAN removal together with important reductions of the other considered contaminants could be achieved, thus meeting the requirements for reuse of seawater in RAS systems. TAN removal, mainly due to an indirect oxidation mechanism was described by a second order kinetics while COD and nitrite removal followed zero-th order kinetics. The values of the kinetic constants for the anodic oxidation of each compound were obtained as a function of the applied current density (k(TAN) = 7.86 × 10(-5) · exp(6.30 × 10(-2) J); kNO2 = 3.43 × 10(-2) J; k(COD) = 1.35 × 10(-2) J). The formation of free chlorine and oxidation by-products, i.e., trihalomethanes (THMs) was followed along the electro-oxidation process. Although a maximum concentration of 1.7 mg l(-1) of total trihalomethanes was detected an integrated process combining electrochemical oxidation in order to eliminate TAN, nitrite and COD and adsorption onto activated carbon to remove the residual chlorine and THMs is proposed, as an efficient alternative to treat and reuse the seawater in fish culture systems. Finally, the energy consumption of the treatment has been evaluated. PMID:20832837

  4. Soil nitrifying enrichments as biofilter starters in intensive recirculating saline water aquaculture

    E-print Network

    Gross, Amit

    aquaculture Abstract Intensive recirculating aquaculture relies on biofilters to sustain satisfactory water quality in the ponds. Establishment of new biofilters in aquaculture ponds without a start-up culture

  5. Ammonia Conversion Characteristics in a Closed Recirculating Aquaculture System

    Microsoft Academic Search

    Guang-Yu Wang; Ji-xian Yang; Fang Ma; Lei Chen; Wei-Guo Li; Jingbo Guo

    2009-01-01

    Nitrification and denitrification were commonly used in the recirculating aquaculture system (RAS) to decrease the ammonia and nitrate concentration. The variation characteristics of nitrogenous compounds and microbiology in a closed RAS were studied with gradually increasing ammonia-nitrogen (NH4 +-N) concentration. The NH4 +-N was completely converted into nitrite nitrogen (NO2 --N) in 46 days, but the NO2 --N raised slowly

  6. Growth Performance of Walleye, Sander vitreus, in Recirculating Aquaculture Systems

    Microsoft Academic Search

    Chester B. Zarnoch; Martin P. Schreibman; Richard T. Colesante; Michael B. Timmons

    2010-01-01

    Walleye, Sander vitreus, fingerlings were reared in two recirculating aquaculture systems (RAS) to compare growth performance at three stocking densities (11, 24, and 36 kg\\/m). There was a negative relationship between increasing stocking density and growth calculated as percent body weight (BW) gain\\/day, total length (mm) gain\\/day, specific growth rate (SGR) of weight (%\\/day), and SGR of total length (%\\/day).

  7. Combination of a bead filter and rotating biological contactor in a recirculating fish culture system

    Microsoft Academic Search

    Aurelio A. delos Reyes; Thomas B. Lawson

    1996-01-01

    The performance of the combination of a floating bead filter and an RBC employing 1-inch diameter N?orpac® tube media was evaluated in an intensive pilot scale recirculating system stocked with tilapia. The combination maintained favorable water quality, attaining practically complete TAN and NO2-N removal. The average overall removal across the FBF-RBC combination was 60·6 g TAN\\/day and 59·6 g NO2-N\\/day,

  8. Growth and Culture of Larval and Juvenile Tautogs in a Closed Recirculating-Seawater System

    Microsoft Academic Search

    Dean M. Perry; Renee Mercaldo-Allen; Stacy Burgh

    2001-01-01

    Field-captured and laboratory-held adult tautogs Tautoga onitis were allowed to spawn naturally under laboratory conditions. Embryos were cultured to hatching and raised successfully through the larval stage to 490-d-old posthatch juveniles. A large (8,500-L), closed, recirculating-seawater system, designed with a biological filter containing air diffusers that passed a strong air?water mixture through a high-surface-area substrate, was used to culture the

  9. Parameters affecting HS emissions removal and re-circulating water quality in a pilot-scale sequential biological treatment system at a wastewater lift station in Brownsville, Texas, USA.

    PubMed

    Karre, Anand K; Bairu, Pavan; Jones, Kim D; Paca, Jan

    2012-01-01

    In this study, a pilot-scale sequential biological treatment system combining a biotrickling filter and biofilter was used to optimize the removal of variable emission H(2)S loadings ranging from 30 to 120 g m(-3) h(-1)at a wastewater lift station in Brownsville, Texas USA. The biotrickling filter recycle water pH remained between 2.0 to 3.0 during the four months of unit operation and the overall removal efficiency for H(2)S was >99%. The biotrickling filter removal efficiency was 70 ± 8%, with an elimination capacity of 10 to 80 g m(-3) h(-1) while the biofilter elimination capacity ranged from 10 to 40 g m(-3) h(-1). The sequential treatment system was operated initially at an Empty Bed Residence Time (EBRT) of 120 s (50 s for the biotrickling filter and 70 s for biofilter) for two months and then at an EBRT of 60 s (25 s for biotrickling filter and 35s for biofilter) for the remainder of the operating period; remarkably, there was only a slight decrease in removal efficiency at 60 s EBRT. In order to qualitatively evaluate the changes in recycle water quality in the system on the performance of the unit in precipitating sulfur species, the equilibrium chemical model, Visual MINTEQ was employed. The model predicted speciation results based on the feed water quality and sulfur loadings, and also forecast some iron-sulfur complexes which have potential to form some complex precipitates. This research demonstrated that low pH re-circulating water quality in the biological treatment of H(2)S was possible without compromising the high removal efficiency, and that an improved understanding of the recycle water chemistry of the trickling unit of a sequential treatment system could be useful in the overall optimization of the process. PMID:22486667

  10. Inactivation of bacteria using ultraviolet irradiation in a recirculating salmonid culture system

    Microsoft Academic Search

    Mark J. Sharrer; Steven T. Summerfelt; Graham L. Bullock; Lauren E. Gleason; Jessica Taeuber

    2005-01-01

    The objective of this research was to determine the ultraviolet (UV) irradiation dosages required to inactivate bacteria in a commercial-scale recirculating salmonid culture system. Research was conducted in the commercial-scale recirculating system used for Arctic char growout at the Conservation Fund Freshwater Institute (Shepherdstown, West Virginia). This recirculating system uses a UV channel unit to treat 100% of the 4750L\\/min

  11. Chemical Transformation of Market Waste Anaerobic Degradation in Recirculation and Non-recirculation System

    Microsoft Academic Search

    Cheevanuch Tubtong; Sirintornthep Towprayoon; Pawinee Chaiprasert; Annop Nopharatana; Pantip Kayee

    The batch studies of 30 kg. market waste (Cabbage 40%, Chinese cabbage 20%, other vegetable 20% and fruit 20%) anaerobic degradation was conducted in the lab scale units. These studies investigated the chemical transformation of organic degradation under anaerobic condition with and without the application of leachate recirculation. The chemical transformation focused on chemical oxygen demand (COD) and total volatile

  12. A novel approach to denitrification processes in a zero-discharge recirculating system for small-scale urban aquaculture

    Microsoft Academic Search

    Alon Singer; Shmuel Parnes; Amit Gross; Amir Sagi; Asher Brenner

    2008-01-01

    This paper presents an innovative process to solve the nitrate build-up problem in recirculating aquaculture systems (RAS). The novel aspects of the process lie in a denitrification bioreactor system that uses solid cotton wool as the primary carbon source and a unique degassing chamber. In the latter, the water is physically stripped of dissolved gaseous O2 (by means of a

  13. The use of high rate algal ponds for the treatment of marine effluent from a recirculating fish rearing system

    Microsoft Academic Search

    P Pagand; J-P Blancheton; J Lemoalle; C Casellas

    2000-01-01

    A high rate algal pond (HRAP) system was used to treat effluent from a recirculating sea water aquaculture system in southern France. Dicentrarchus labrax L. were farmed at a high density, with effluents containing an average of 10 mg L1 dissolved inorganic nitrogen (DIN) and 1.3 mg L1 reactive phosphorus (RP). On a yearly basis, the algal pond removed 59%

  14. The potential use of constructed wetlands in a recirculating aquaculture system for shrimp culture.

    PubMed

    Lin, Ying-Feng; Jing, Shuh-Ren; Lee, Der-Yuan

    2003-01-01

    A pilot-scale constructed wetland unit, consisting of free water surface (FWS) and subsurface flow (SF) constructed wetlands arranged in series, was integrated into an outdoor recirculating aquaculture system (RAS) for culturing Pacific white shrimp (Litopenaeus vannamei). This study evaluated the performance of the wetland unit in treating the recirculating wastewater and examined the effect of improvement in water quality of the culture tank on the growth and survival of shrimp postlarvae. During an 80-day culture period, the wetland unit operated at a mean hydraulic loading rate of 0.3 m/day and effectively reduced the influent concentrations of 5-day biochemical oxygen demand (BOD5, 24%), suspended solids (SS, 71%), chlorophyll a (chl-a, 88%), total ammonium (TAN, 57%), nitrite nitrogen (NO2-N, 90%) and nitrate nitrogen (NO3-N, 68%). Phosphate (PO4-P) reduction was the least efficient (5.4%). The concentrations of SS, Chl-a, turbidity and NO3-N in the culture tank water in RAS were significantly (Psystem (CAS) that simulated static pond culture without wetland treatment. However, no significant difference (Psystems. At the end of the study, the harvest results showed that shrimp weight and survival rate in the RAS (3.8 +/-1.8 g/shrimp and 90%) significantly (Pwater quality and provide a good culture environment, consequently increasing the shrimp growth and survival without water exchange, in a recirculating system. PMID:12663210

  15. TRACG Simulation of Drywell Gas Recirculation System in ESBWR

    SciTech Connect

    Cheung, Yee K.; Rao, Atambir S. [GE Nuclear Energy, 175 Curtner Avenue San Jose, California 95125 (United States)

    2002-07-01

    This paper presents the results of a parametric study on the mitigating effects of the Drywell Gas Recirculation System (DGRS) in ESBWR during postulated LOCA and severe accidents. The post-accident containment pressure depends on the sum of the partial pressure from non-condensable gases and partial steam pressure inside the wet-well airspace. Results of parametric studies show that, with the activation of DGRS: (1) The containment pressure continues to reduce due to the redistribution of non-condensable gases from the wet-well back to the drywell; (2) The DGRS can be designed in a 'portable' fashion; (3) The Current ESBWR meets the design requirement with significant margin using only passive safety systems, and the margin increases considerably with the activation of DGRS. (authors)

  16. REDUCING THE ENVIRONMENTAL IMPACT OF HIGH-DENSITY FISH PRODUCTION: AN INTEGRATED APPROACH TO SOLIDS TREATMENT FOR RECIRCULATING AQUACULTURE SYSTEMS USING EXPANDABLE GRANULAR BIOFILTERS1

    Microsoft Academic Search

    William J. Golz; Shulin Chen; Ronald F. Malone

    Over the past decade, the environmental impact of wastes discharged from high-density flow-through fish-production systems has been viewed with increasing concern. Recirculating aquaculture systems are gaining wider acceptance because of their ability to reduce waste discharges, improve quality control, and reduce costs. The crucial processes that must be addressed in treating recirculating water are solids capture, biofiltration, aeration, degasification, and

  17. Evaluation of polyhydroxybutyrate as a carbon source for recirculating aquaculture water denitrification

    Microsoft Academic Search

    Kelly A. Rusch; Ronald F. Malone

    2012-01-01

    The effect of salinity, dissolved oxygen and NO3-N concentration on the denitrification of recirculating aquaculture water using polyhydroxybutyrate (PHB) was evaluated. Four PHB media with different molecular weights and configurations were tested. The results show that at higher nitrate concentrations in the influent water, the consumed PHB:NO3-N ratio decreased. An average of 2.9 g of PHB:1 g NO3-N removed at

  18. A recirculating coronal discharge system for air cleaning

    SciTech Connect

    Vogtlin, G.E.; Hofer, W.W.; Penetrante, B.M. [Lawrence Livermore National Lab., CA (United States)] [and others

    1992-12-01

    A recirculating gas cleaning system has been constructed incorporating a pulsed plasma reactor in coaxial cylinder geometry, with a wire of diameter 1.59mm inside a stainless steel cylinder of inner radius 10.6mm. Positive corona are formed by the application of pulses of up to 45 kV with rise times of 10-20 ns, pulse lengths of 50-200 ns and peak currents up to 500 A. Higher voltages lead to premature arc formation. Flow rates of up to 2 liters per second can be achieved in the 4.6 liter gas system, and filters are included to remove the acids formed from the pollutant molecules. First tests of the system using NO at initial levels around 100 ppm show that 99% destruction can be achieved with approximately 250 pulses. No NO removal is seen if the air is replaced by dry nitrogen, showing the crucial role of radicals produced from O{sub 2} and/or H{sub 2}O. Further experiments are underway to determine the dependence of the process efficiency on the electrical characteristics, and on the humidity level of the air, and to check the predictions of discharge simulations described elsewhere at this meeting.

  19. Performance of the prototype gas recirculation system with built-in RGA for INO RPC system

    NASA Astrophysics Data System (ADS)

    Bhuyan, M.; Datar, V. M.; Joshi, A.; Kalmani, S. D.; Mondal, N. K.; Rahman, M. A.; Satyanarayana, B.; Verma, P.

    2012-01-01

    An open loop gas recovery and recirculation system has been developed for the INO RPC system. The gas mixture coming from RPC exhaust is first desiccated by passing through molecular sieve (3 Å+4 Å). Subsequent scrubbing over basic active alumina removes toxic and acidic contaminants. The Isobutane and Freon are then separated by diffusion and liquefied by fractional condensation by cooling up to -26C. A Residual Gas Analyser (RGA) is being used in the loop to study the performance of the recirculation system. The results of the RGA analysis will be discussed.

  20. Modeling gas transfer and biological respiration in a recirculating aquaculture system

    Microsoft Academic Search

    Luther G. Wood; Barnaby J. Watten; C. Gene Haugh; George S. Libey; Theo A. Dillaha

    1996-01-01

    Recirculating aquaculture system applications of oxygen absorption equipment require consideration of the combined effects of the system's physical, chemical and biological components. Interactions of this type were modeled within a recirculating system incorporating a mixed-flow type rearing vessel, a multi-tube clarifier, a rotating biological contactor (RBC) and a U-tube oxygenator. Finite difference mass transfer calculations, based on reactor theory, were

  1. Analysis of the sodium recirculation theory of solute-coupled water transport in small intestine

    PubMed Central

    Larsen, Erik Hviid; Sørensen, Jakob Balslev; Sørensen, Jens Nørkær

    2002-01-01

    Our previous mathematical model of solute-coupled water transport through the intestinal epithelium is extended for dealing with electrolytes rather than electroneutral solutes. A 3Na+–2K+ pump in the lateral membranes provides the energy-requiring step for driving transjunctional and translateral flows of water across the epithelium with recirculation of the diffusible ions maintained by a 1Na+-1K+–2Cl? cotransporter in the plasma membrane facing the serosal compartment. With intracellular non-diffusible anions and compliant plasma membranes, the model describes the dependence on membrane permeabilities and pump constants of fluxes of water and electrolytes, volumes and ion concentrations of cell and lateral intercellular space (lis), and membrane potentials and conductances. Simulating physiological bioelectrical features together with cellular and paracellular fluxes of the sodium ion, computations predict that the concentration differences between lis and bathing solutions are small for all three ions. Nevertheless, the diffusion fluxes of the ions out of lis significantly exceed their mass transports. It is concluded that isotonic transport requires recirculation of all three ions. The computed sodium recirculation flux that is required for isotonic transport corresponds to that estimated in experiments on toad small intestine. This result is shown to be robust and independent of whether the apical entrance mechanism for the sodium ion is a channel, a SGLT1 transporter driving inward uphill water flux, or an electroneutral Na+–K+–2Cl? cotransporter. PMID:12096047

  2. Ozonation followed by ultraviolet irradiation provides effective bacteria inactivation in a freshwater recirculating system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recirculating aquaculture systems may require an internal disinfection process to control population growth of pathogens and heterotrophic bacteria. Ozonation and ultraviolet (UV) irradiation are two technologies that have been used to treat relatively large aquaculture flows, including flows withi...

  3. Fish Health Management Considerations in Recirculating Aquaculture systems -Part 3: General

    E-print Network

    Watson, Craig A.

    Cir 122 Fish Health Management Considerations in Recirculating Aquaculture systems -Part 3: General Professor, Tropical Aquaculture Laboratory, Ruskin FL 33570, Department of Fisheries and Aquatic Sciences commonly used in aquaculture facilities, wholesale and retail tropical fish facilities, and public aquaria

  4. Temporal and Spatial Pore Water Pressure Distribution Surrounding a Vertical Landfill Leachate Recirculation Well

    PubMed Central

    Kadambala, Ravi; Townsend, Timothy G.; Jain, Pradeep; Singh, Karamjit

    2011-01-01

    Addition of liquids into landfilled waste can result in an increase in pore water pressure, and this in turn may increase concerns with respect to geotechnical stability of the landfilled waste mass. While the impact of vertical well leachate recirculation on landfill pore water pressures has been mathematically modeled, measurements of these systems in operating landfills have not been reported. Pressure readings from vibrating wire piezometers placed in the waste surrounding a liquids addition well at a full-scale operating landfill in Florida were recorded over a 2-year period. Prior to the addition of liquids, measured pore pressures were found to increase with landfill depth, an indication of gas pressure increase and decreasing waste permeability with depth. When liquid addition commenced, piezometers located closer to either the leachate injection well or the landfill surface responded more rapidly to leachate addition relative to those far from the well and those at deeper locations. After liquid addition stopped, measured pore pressures did not immediately drop, but slowly decreased with time. Despite the large pressures present at the bottom of the liquid addition well, much smaller pressures were measured in the surrounding waste. The spatial variation of the pressures recorded in this study suggests that waste permeability is anisotropic and decreases with depth. PMID:21655145

  5. Blue tilapia ( Oreochromis aureus) growth rate in relation to dissolved oxygen concentration under recirculated water conditions

    Microsoft Academic Search

    Sofronios E. Papoutsoglou; Gar. Tziha

    1996-01-01

    The growth rate of Oreochromis aureus in relation to dissolved oxygen concentrations (2·63±0·12, 3·75±0·12, 6·51±0·13 ppm or 31·3, 44·6 and 77·5% saturation, respectively) was investigated. Three duplicated populations of 29 specimens (mean initial body weight ?27·3 g) were reared in 100-litre tanks for 200 days under recirculated water conditions. Fish were offered an artificial diet three times per day, 6

  6. Full-scale demonstration of in situ cometabolic biodegradation of trichloroethylene in groundwater 1. Dynamics of a recirculating well system

    NASA Astrophysics Data System (ADS)

    Gandhi, Rahul K.; Hopkins, Gary D.; Goltz, Mark N.; Gorelick, Steven M.; McCarty, Perry L.

    2002-04-01

    Recirculating well systems provide an engine for the in situ treatment of subsurface contaminants. Although numerous recirculating wells have been installed in the field, for such systems, there is a paucity of comprehensive monitoring data and models constrained to data appearing in the research literature. Here we present an extensive data set combined with detailed inverse and simulation analyses for a two-well groundwater recirculation system used for in situ bioremediation at Edwards Air Force Base in southern California. The ``conveyor belt'' flow system, which was established for in situ treatment of trichloroethylene (TCE) in two bioactive zones, was created by pumping water upward in one well and downward in another well, each well being screened in both the upper and lower aquifers. A bromide tracer test was conducted and extensively monitored for 60 days. Combined inverse analysis was conducted on hydraulic heads from 38 monitoring wells, 32 bromide concentration histories, and a constraint on the degree of recirculation that was based on TCE concentration data. Four different formulations involving alternative weighting schemes used in a nonlinear weighted least squares simulation-regression analysis were explored. The best formulation provided parameter estimates with tight bounds on estimated covariances, suggesting that the model provides a reasonable description of the hydrogeologic system. Our investigation indicates the geometry of the recirculation zone and the degree of recirculation under two different sets of operating conditions. Surprisingly, our analysis suggests that the effects of aquifer heterogeneity are not significant at this site under the conditions of forced recirculation. Furthermore, anomalous flow through an open monitoring well created significant vertical short-circuiting between the generally insulated aquifers. Flow through this small open conduit was equivalent to as much as 33% of the flow through the pumping wells. Using the model as a guide, we treated the aquifer system and bioactive zones as an equivalent mixed reactor to develop simple expressions relating effluent concentrations to influent concentrations. We demonstrate how these expressions are useful in predicting the removal of TCE that had undergone in situ bioremediation in the recirculatory treatment well system. The finite element model developed in this work serves as the foundation for a reactive transport simulator that we developed to analyze bioremediation which occurred during a 444 day experiment [Gandhi et al., 2002].

  7. Performance of a constructed wetland in treating brackish wastewater from commercial recirculating and super-intensive shrimp growout systems.

    PubMed

    Shi, Yonghai; Zhang, Genyu; Liu, Jianzhong; Zhu, Yazhu; Xu, Jiabo

    2011-10-01

    A recirculating aquaculture system was developed for treating Pacific white shrimp (Litopenaeus vannamei) production wastewater using an integrated vertical-flow (IVF) and five connected integrated horizontal flow (IHF) constructed wetlands as water treatment filters for mesohaline conditions (8.25‰-8.26‰ salinity). The constructed wetlands demonstrated the ability to reduce total nitrogen, total ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, total phosphorous, chemical oxygen demand, and total suspended solids to levels significantly lower than those in effluents from culture tanks. Various water quality parameters in the culture tanks were deemed suitable for shrimp culture. The actual ratio of wetland area (A(w)) to culture tank area (A(t)) was 1.1439, and the estimated optimal ratio A(w)/A(t) was approximately 1. The IVF-IHF wetlands showed flexibility and reliability in consistently removing the main pollutants from commercial recirculating and super-intensive shrimp growout systems throughout the culture period. PMID:21852127

  8. Nitrogen removal in a two-stage, re-circulating waste stabilisation pond system.

    PubMed

    Baskaran, K; Farago, L

    2007-01-01

    Waste stabilisation ponds are used widely in Australia and other parts of the world for treating wastewater from domestic and a wide range of industrial sources. It remains a popular form of treatment for wastewater for many small rural towns. The development of a two-stage, re-circulating waste stabilisation pond incorporating algal-bacterial biofilm represents a new approach to increasing the functioning biomass within the water column to improve treatment efficiency. This new approach will be a more viable and economical option for most of the existing waste stabilisation ponds to achieve significant nitrogen removal than converting them to another form of biological nutrient removal processes. A laboratory-scale, two-stage, re-circulating system incorporating "Bio-Tube" plastic modules as attached growth medium has been tested using synthetic wastewater. It has been proven that nitrification-denitrification was the primary mechanism for nitrogen removal in such a system operated under complete mix conditions. During the experimental period, average removal efficiencies of 90-95% of ammonia nitrogen and 65-85% of total nitrogen removal were achieved with influent COD of 600 mg/L and total nitrogen of 70 mg/L. PMID:17591196

  9. Performance characteristics of fluidised bed biofilters in a novel laboratory-scale recirculation system for rainbow trout: nitrification rates, oxygen consumption and sludge collection

    Microsoft Academic Search

    J Skjølstrup; P. H Nielsen; J.-O Frier; E McLean

    1998-01-01

    A laboratory-scale recirculating aquaculture system for fluidised bed biofilter evaluation was engineered. The design included all components found in typical full-scale commercial production systems. The system included two identical units each with oxygenation, UV treatment, cooling, biofiltration and a particulates separation device. Water from the two systems was mixed in a degassing unit. A 1 month test period after biofilter

  10. Dynamic Scheduling of Internal Exhaust Gas Recirculation Systems.

    E-print Network

    Stefanopoulou, Anna

    -fuel charge and lower the combustion temperature which reduces NOx feedgas emissions. Conventionally, exhaust gas recirculation. The dynamic sched- ule consists of a steady-state map of the camshaft timing- trogen (NOx) in internal combustion engines. The in- ert exhaust gases dilute the inducted air

  11. Performance of a constructed wetland in treating brackish wastewater from commercial recirculating and super-intensive shrimp growout systems

    Microsoft Academic Search

    Yonghai Shi; Genyu Zhang; Jianzhong Liu; Yazhu Zhu; Jiabo Xu

    2011-01-01

    A recirculating aquaculture system was developed for treating Pacific white shrimp (Litopenaeus vannamei) production wastewater using an integrated vertical-flow (IVF) and five connected integrated horizontal flow (IHF) constructed wetlands as water treatment filters for mesohaline conditions (8.25‰–8.26‰ salinity). The constructed wetlands demonstrated the ability to reduce total nitrogen, total ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, total phosphorous, chemical oxygen demand,

  12. Development and design of a fluidized bed\\/upflow sand filter configuration for use in recirculating aquaculture systems

    Microsoft Academic Search

    1988-01-01

    A fluidized bed\\/upflow sand filter configuration, was developed and designed for utilization in recirculating aquaculture system, specifically the soft-shell crab and soft-shell crawfish industries. These filters were selected and designed because of their ability to withstand clogging and still maintain high levels of water quality for aquaculture production. The effectiveness of sand grain size was used to evaluate fluidized bed

  13. Systems engineering for ornamental fish production in a recirculating aquaculture system

    Microsoft Academic Search

    Ilan Halachmi

    2006-01-01

    The aim was to develop a simulation model for determining the optimal layout and management regime for ornamental fish recirculating aquaculture system (ORAS). The work plan involved: (1) quantifying the effects of fish growth rates, the nature of the products, and the management practices; (2) developing a mathematical simulation model of the ORAS, taking into account all factors that directly

  14. Electron recirculation in electrostatic multicusp systems: II. System performance scaling of one-dimensional rollover wells

    Microsoft Academic Search

    R. W. Bussard; K. E. King

    1992-01-01

    In an earlier paper a comprehensive study was made of the recirculation and losses of electrons in their flow through simple inverse power-law potential wells bounded by similarly inverse power-law dependent magnetic fields. This study examined electron flow and loss behavior in the simplest approximation invoked to describe Polywell confinement systems. The importance of this study, and of the present

  15. Demonstration of a Highly Efficient Solid Oxide Fuel Cell Power System Using Adiabatic Steam Reforming and Anode Gas Recirculation

    SciTech Connect

    Powell, Michael R.; Meinhardt, Kerry D.; Sprenkle, Vincent L.; Chick, Lawrence A.; Mcvay, Gary L.

    2012-05-01

    Solid oxide fuel cells (SOFC) are currently being developed for a wide variety of applications because of their high efficiency at multiple power levels. Applications for SOFCs encompass a large range of power levels including 1-2 kW residential combined heat and power applications, 100-250 kW sized systems for distributed generation and grid extension, and MW-scale power plants utilizing coal. This paper reports on the development of a highly efficient, small-scale SOFC power system operating on methane. The system uses adiabatic steam reforming of methane and anode gas recirculation to achieve high net electrical efficiency. The anode exit gas is recirculated and all of the heat and water required for the endothermic reforming reaction are provided by the anode gas emerging from the SOFC stack. Although the single-pass fuel utilization is only about 55%, because of the anode gas recirculation the overall fuel utilization is up to 93%. The demonstrated system achieved gross power output of 1650 to 2150 watts with a maximum net LHV efficiency of 56.7% at 1720 watts. Overall system efficiency could be further improved to over 60% with use of properly sized blowers.

  16. Applying rotary jet heads for mixing and mass transfer in a forced recirculation tank reactor system

    Microsoft Academic Search

    Mikkel Nordkvist; Thomas Grotkjær; Jan S. Hummer; John Villadsen

    2003-01-01

    An approximation to an ideally mixed tank reactor can be obtained by vigorous stirring with mechanical mixers. For an aerated reactor the gas dispersion contributes to the mixing process. Mixing can also be achieved by recirculation of a portion of the liquid through either an internal or an external loop.In this study, we determine mixing times in water and CMC

  17. Internal dust recirculation system for a fluidized bed heat exchanger

    DOEpatents

    Gamble, Robert L. (Wayne, NJ); Garcia-Mallol, Juan A. (Morristown, NJ)

    1981-01-01

    A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam/water natural circulation system is provided in a heat exchange relation to the bed and includes a steam drum disposed adjacent the bed and a tube bank extending between the steam drum and a water drum. The tube bank is located in the path of the effluent gases exiting from the bed and a baffle system is provided to separate the solid particulate matter from the effluent gases. The particulate matter is collected and injected back into the fluidized bed.

  18. Radioactive particle tracking technique for investigation of phase recirculation and turbulence in multiphase systems

    NASA Astrophysics Data System (ADS)

    Moslemian, D.; Devanathan, N.; Dudukovic, M. P.

    1992-10-01

    The development of a noninvasive PC-based computer automated radioactive particle tracking (CARPT) facility for investigation of phase recirculation and turbulence in multiphase systems such as fluidized beds and bubble columns is presented. In this facility, the motion of a single radioactive particle, which is dynamically similar to the recirculating phase, is monitored by an array of scintillation detectors which surround the test section. An on-line computer is used to map the flow field of the recirculating phase. The data acquisition is achieved by commercially available nuclear instrumentation via a modular, high-speed GPIB-CAMAC system through assembly language software. Using CARPT, solids' motion in gas-fluidized beds and liquid motion in bubble columns have been investigated. The capabilities and versatility of the CARPT facility is described by illustrating some typical results for mean recirculation in gas-fluidized beds with and without internals and in a gas-liquid bubble column. The results include the mean circulation profiles and turbulence parameters such as the Reynolds normal and shear stresses and the turbulent eddy dispersion coefficients. Potential applications of CARPT technique to other recirculating systems are also discussed.

  19. Oxygen mass balance in a recirculation aquaculture system for raising European Wels (Silurus glanis L.)

    Microsoft Academic Search

    Viktoras Mongirdas; Albinas Kusta

    2006-01-01

    The growth of the European Wels or sheat-fish (Silurus glanis L.) was eva- luated in a recirculation aquaculture system situated in a greenhouse. Recir- culation aquaculture system components were evaluated in terms of oxygen use and generation. Oxygen gradients revealed the main fault of the originally constructed system elements - mechanical and biological filters. The influen- ce of organic matter

  20. Off-flavors in salmonids raised in recirculating aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Producers of aquaculture products will typically verify the flavor quality of their product by sensory evaluation (flavor testing) before harvesting the crop for market. “Off-flavors” detected in the product may require holding the fish in a purging system containing fresh, clean water to depurate ...

  1. Use of a micro programmable logic controller for oxygen monitoring and control in multiple tanks of a recirculating aquaculture system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In intensive recirculating aquaculture systems the use of supplemental oxygen, specifically pure liquid oxygen, increases the mass of fish that can be supported and eliminates oxygen as a major limiting factor to a system’s carrying capacity. The use of pure oxygen in a recirculating aquaculture sys...

  2. Production characteristics of body composition of Florida pompano reared to market size at two different densities in low salinity recirculating aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of culture density on production characteristics and body composition of Florida pompano Trachinotus carolinus reared to market size using recirculating aquaculture systems (RAS) at a salinity of 5 g/L was evaluated in a 110 day growth trial (water temperature, 27.0-28.5 C). Juvenile pom...

  3. A semi-recirculating, integrated system for the culture of fish and seaweed

    Microsoft Academic Search

    Andreas Schuenhoff; Muki Shpigel; Ingrid Lupatsch; Arik Ashkenazi; Flower E Msuya; Amir Neori

    2003-01-01

    Biofiltration allows for environmentally sustainable mariculture. An intensive, biofiltered recirculating integrated system producing fish and seaweed on a semi-commercial scale was evaluated with respect to production and to nutrient and heat budgets. The system consisted of abalone (Haliotis discus hannai) and sea urchin (Paracentrotus lividus) tanks, an intensive fishpond (Sparus aurata), and a three-stage Ulva lactuca biofilter, which cleaned and

  4. A novel computer simulation model for design and management of re-circulating aquaculture systems

    Microsoft Academic Search

    Ilan Halachmi; Yitzchak Simon; Rami Guetta; Eric M. Hallerman

    2005-01-01

    The aim of this study was to develop a simulation model for finding the optimal layout and management regime for a re-circulating aquaculture system (RAS). The work plan involved: (1) quantifying the effects of fish growth and management practices on production; (2) developing a mathematical simulation model for the RAS, taking into account all factors that directly influence system profitability;

  5. Performance of a commercial recirculating alligator production system employing a paddle-washed floating bead filter

    Microsoft Academic Search

    Aurelio A. DelosReyes; Kelly A. Rusch; Ronald F. Malone

    1997-01-01

    A 2.83 m3 prototype paddle-washed bead filter for combined solids capture and biological filtration was successfully operated in a commercial recirculating alligator (Alligator mississippiensis) facility. The bead filter was originally designed and operated as a downflow filter but due to operational and water quality problems, it was reconfigured to operate in an upflow mode. Water quality conditions and filter performance

  6. Field evaluation of a horizontal well recirculation system for groundwater treatment: Pilot test at the Clean Test Site Portsmouth Gaseous Diffusion Plant, Piketon, Ohio

    SciTech Connect

    Muck, M.T.; Kearl, P.M.; Siegrist, R.L. [and others] [and others

    1998-08-01

    This report presents the results of field testing a horizontal well recirculation system at the Portsmouth Gaseous Diffusion Plant (PORTS). The recirculation system uses a pair of horizontal wells, one for groundwater extraction and treatment and the other for reinjection of treated groundwater, to set up a recirculation flow field. The induced flow field from the injection well to the extraction well establishes a sweeping action for the removal and treatment of groundwater contaminants. The overall purpose of this project is to study treatment of mixed groundwater contaminants that occur in a thin water-bearing zone not easily targeted by traditional vertical wells. The project involves several research elements, including treatment-process evaluation, hydrodynamic flow and transport modeling, pilot testing at an uncontaminated site, and pilot testing at a contaminated site. The results of the pilot test at an uncontaminated site, the Clean Test Site (CTS), are presented in this report.

  7. RECIRCULATING AQUACULTURE SYSTEM FOR MARINE FINFISH RESEARCH AT HARBOR BRANCH OCEANOGRAPHIC INSTITUTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recirculating aquaculture systems (RAS,) for both commercial and experimental uses, has been under development in many parts of the world in response to several driving forces. With regards to sites for coastal aquaculture, the scarcity of affordable land has driven aquaculture endeavors for marine ...

  8. Geosmin causes off-flavour in arctic charr in recirculating aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The “earthy” and “muddy” off-flavors in pond-reared fish are due to the presence of geosmin or 2-methylisoborneol (MIB) in the flesh of the fish. Similar off-flavors have been reported in fish raised in recirculating aquaculture systems (RAS); however, little information is available regarding the ...

  9. Quantification of anammox activity in a denitrification reactor for a recirculating aquaculture system

    Microsoft Academic Search

    Ori Lahav; Iris Bar Massada; Dimitry Yackoubov; Ruth Zelikson; Noam Mozes; Yossi Tal; Sheldon Tarre

    2009-01-01

    The activity of anammox bacteria in a denitrification reactor in a recirculating aquaculture system (RAS) for gilthead seabream production was investigated. Organic matter, extracted from the pond's solid filter, was used as the electron donor and carbon source for the denitrification reaction. The reactor was operated at four solid retention times (SRT). At steady state, anammox activity showed similar activity

  10. On thermoelectric power conversion from heat re-circulating combustion systems F. J. Weinberg

    E-print Network

    On thermoelectric power conversion from heat re-circulating combustion systems F. J. Weinberg Fax: 4420 7594 5604 Word count: 3750 Diags. equivalent: 1600 5350 #12;On thermoelectric power the absolute maximum efficiency of energy conversion by thermoelectric devices that operate as part of the heat

  11. Molecular Adsorbents Recirculating System in Patients with Severe Liver Failure. Experience of a Single Romanian Centre

    Microsoft Academic Search

    Elena-Emanuela Rusu; Mihai Voiculescu; Diana-Silvia Zilisteanu; Gener Ismail

    Aim: This is a retrospective, observational study regarding the experience of the Fundeni Clinical Institute in the application of the Molecular Adsorbents Recirculating System in patients with liver failure. Method: From January 2002 until December 2007, we performed 50 MARS sessions in 27 patients, mean age 38.96 ± 19.58 years. The etiology of liver failure was as follows: acute liver

  12. Electronic fuel supply control system for internal combustion engines, having exhaust gas recirculation control

    Microsoft Academic Search

    A. Yamato; S. Umesaki

    1984-01-01

    In an electronic fuel supply control system for an internal combustion engines, the fuel quantity being supplied to the engine is set to different values in accordance with the operating condition of the engine, between when the exhaust gas recirculation is operated and when it is not operated, for achieving proper air\\/fuel ratios. Further, immediately after a valve lift command

  13. Solids removal from a coldwater recirculating system - comparison of swirl separator and radial-flow settlers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Solids removal across two settling devices, i.e., a swirl separator and a radial-flow settler, and across a microscreen drum filter was evaluated in a fully recirculating system containing a single 150 m3 'Cornell-type' dual-drain tank during the production of food-size Arctic char and rainbow trout...

  14. A study on the optimal hydraulic loading rate and plant ratios in recirculation aquaponic system.

    PubMed

    Endut, Azizah; Jusoh, A; Ali, N; Wan Nik, W B; Hassan, A

    2010-03-01

    The growths of the African catfish (Clarias gariepinus) and water spinach (Ipomoea aquatica) were evaluated in recirculation aquaponic system (RAS). Fish production performance, plant growth and nutrient removal were measured and their dependence on hydraulic loading rate (HLR) was assessed. Fish production did not differ significantly between hydraulic loading rates. In contrast to the fish production, the water spinach yield was significantly higher in the lower hydraulic loading rate. Fish production, plant growth and percentage nutrient removal were highest at hydraulic loading rate of 1.28 m/day. The ratio of fish to plant production has been calculated to balance nutrient generation from fish with nutrient removal by plants and the optimum ratio was 15-42 gram of fish feed/m(2) of plant growing area. Each unit in RAS was evaluated in terms of oxygen demand. Using specified feeding regime, mass balance equations were applied to quantify the waste discharges from rearing tanks and treatment units. The waste discharged was found to be strongly dependent on hydraulic loading rate. PMID:19819130

  15. Formation of disinfection byproducts in a recirculating mariculture system: emerging concerns.

    PubMed

    Qiang, Zhimin; Zhang, Haiting; Dong, Huiyu; Adams, Craig; Luan, Gang; Wang, Lei

    2015-02-01

    Disinfection is commonly employed in recirculating mariculture systems (RMS) to control animal diseases and improve seawater quality; however, little is known about the occurrence of disinfection byproducts (DBPs) formed in such RMS. Beijing Aquarium is a typical RMS with artificially prepared seawater and mainly adopts a decentralized treatment strategy for different animal tanks, including sand filtration, foam fractionation, and disinfection (O3, UV, and O3/ClO2). This study reveals that the adopted disinfection processes were highly effective in controlling marine heterotrophic bacteria; however, some concerns were raised on the formation of various kinds of DBPs, including secondary oxidants, inorganic oxyanions, and hazardous organic species. Free chlorine and free bromine were generated from ozonation at health-relevant concentrations. High concentrations of BrO3(-) and ClO3(-) were formed in mammal tanks, which exceeded the USEPA-regulated maximum contaminant level (MCL) for drinking water by 19-25 and 52-54 times, respectively. Extremely high concentrations of NO3(-) were detected in mammal tanks, which considerably exceeded the MCL regulated by the Sea Water Quality Standard of China for the mariculture industry (Class II) by about 1100 times. Undoubtedly, the presence of various DBPs poses serious health threats to aquarium animals. To solve these problems, potential control measures for DBPs are proposed. PMID:25573452

  16. Milli-Q Reference Water Purification System

    E-print Network

    Woodall, Jerry M.

    Milli-Q® Reference Water Purification System The reference for ultrapure water systems EMD the requirements of the most demanding norms. We've achieved all this with a new purification strategy. Water. This water is sent through a small recirculation loop to the POD pak, where a final purification step

  17. Evaluation of submerged surface flow (SSF) constructed wetlands for recirculating tilapia production systems

    Microsoft Academic Search

    W ZACHRITZII; A. T. Hanson; J. A. Sauceda; K. M. Fitzsimmons

    2008-01-01

    A recirculating aquaculture system (RAS) treating tilapia production wastewaters used a two-step process combining a simple clarifier and a submerged surface flow (SSF) constructed wetlands for suspended solids removal and removal of nitrogenous compounds. This system successfully supported a commercial scale level of production (>35kg\\/m3) for over 36 months of operation. The innovative SSF wetland design incorporated a high hydraulic

  18. 77 FR 19740 - Water Sources for Long-Term Recirculation Cooling Following a Loss-of-Coolant Accident

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-02

    The U.S. Nuclear Regulatory Commission (NRC or the Commission) is issuing a revision to Regulatory Guide (RG) 1.82, ``Water Sources for Long-Term Recirculation Cooling Following a Loss-of-Coolant Accident.'' RG 1.82 describes methods that the NRC staff considers acceptable to implement requirements regarding the sumps and suppression pools that provide water sources for emergency core cooling,......

  19. An evaluation of commercially available biological filters for recirculating aquaculture systems

    Microsoft Academic Search

    Todd C. Guerdat; Thomas M. Losordo; John J. Classen; Jason A. Osborne; Dennis P. DeLong

    2010-01-01

    Three different commercially available biological filters were evaluated in triplicate on a 60m3 tank-based Tilapia system under commercial warmwater growout conditions. The study was performed at the North Carolina State University Fish Barn—a commercial scale research and demonstration recirculating aquaculture facility operated by the department of Biological and Agricultural Engineering. Total ammoniacal nitrogen (TAN) removal rates were determined for the

  20. Nitrification performance of nitrifiers immobilized in PVA (polyvinyl alcohol) for a marine recirculating aquarium system

    Microsoft Academic Search

    Jae-Koan Seo; Il-Hyong Jung; Mi-Ryung Kim; Byong Jin Kim; Soo-Wan Nam; Sung-Koo Kim

    2001-01-01

    Characteristics of the nitrification processes with immobilized nitrifier consortium were evaluated for the development of the marine recirculating aquarium system. In order to evaluate the activity of the nitrifiers, a 45 l airlift reactor was used for the determination of ammonia removal rate for 40 days of operation. The ammonia removal efficiency rate was 98% with 23 g ammonia-N\\/m3\\/day, respectively.

  1. Advanced Horizontal Well Recirculation Systems for Geothermal Energy Recovery in Sedimentary and Crystalline Formations

    SciTech Connect

    Bruno, Mike; Detwiler, Russell L; Lao, Kang; Serajian, Vahid; Elkhoury, Jean; Diessl, Julia; White, Nicky

    2012-12-13

    There is increased recognition that geothermal energy resources are more widespread than previously thought, with potential for providing a significant amount of sustainable clean energy worldwide. Recent advances in drilling, completion, and production technology from the oil and gas industry can now be applied to unlock vast new geothermal resources, with some estimates for potential electricity generation from geothermal energy now on the order of 2 million megawatts. The primary objectives of this DOE research effort are to develop and document optimum design configurations and operating practices to produce geothermal power from hot permeable sedimentary and crystalline formations using advanced horizontal well recirculation systems. During Phase I of this research project Terralog Technologies USA and The University of California, Irvine (UCI), have completed preliminary investigations and documentation of advanced design concepts for paired horizontal well recirculation systems, optimally configured for geothermal energy recovery in permeable sedimentary and crystalline formations of varying structure and material properties. We have also identified significant geologic resources appropriate for application of such technology. The main challenge for such recirculation systems is to optimize both the design configuration and the operating practices for cost-effective geothermal energy recovery. These will be strongly influenced by sedimentary formation properties, including thickness and dip, temperature, thermal conductivity, heat capacity, permeability, and porosity; and by working fluid properties.

  2. Recirculation in venovenous extracorporeal membrane oxygenation.

    PubMed

    Abrams, Darryl; Bacchetta, Matthew; Brodie, Daniel

    2015-01-01

    Recirculation, a phenomenon in which reinfused oxygenated blood is withdrawn by the drainage cannula without passing through the systemic circulation, decreases the efficiency with which venovenous extracorporeal membrane oxygenation (ECMO) provides oxygenation. The precise amount of recirculation may be difficult to quantify. However, interventions should be attempted to reduce recirculation when oxygen delivery is suboptimal and recirculation is suspected. Several techniques, including the use of dual-lumen cannulae, have been successful in minimizing recirculation in venovenous ECMO. This article will provide an overview of the factors that affect recirculation, methods that may be used to quantify recirculation, and interventions that may reduce recirculation, thereby increasing ECMO efficiency. PMID:25423117

  3. Aerobic and Anoxic Growth and Nitrate Removal Capacity of a Marine Denitrifying Bacterium Isolated from a Recirculation Aquaculture System

    Microsoft Academic Search

    Maria-Teresa Borges; André Sousa; Paolo De Marco; Ana Matos; Petra Hönigová; Paula M. L. Castro

    2008-01-01

    Bacterial biofilters used in marine recirculation aquaculture systems need improvements to enhance nitrogen removal efficiency.\\u000a Relatively little is known about biofilter autochthonous population structure and function. The present study was aimed at\\u000a isolating and characterizing an autochthonous denitrifying bacterium from a marine biofilter installed at a recirculation\\u000a aquaculture system. Colonization of four different media in a marine fish farm was

  4. Integrated exhaust gas recirculation and charge cooling system

    DOEpatents

    Wu, Ko-Jen

    2013-12-10

    An intake system for an internal combustion engine comprises an exhaust driven turbocharger configured to deliver compressed intake charge, comprising exhaust gas from the exhaust system and ambient air, through an intake charge conduit and to cylinders of the internal combustion engine. An intake charge cooler is in fluid communication with the intake charge conduit. A cooling system, independent of the cooling system for the internal combustion engine, is in fluid communication with the intake charge cooler through a cooling system conduit. A coolant pump delivers a low temperature cooling medium from the cooling system to and through the intake charge cooler for the transfer of heat from the compressed intake charge thereto. A low temperature cooler receives the heated cooling medium through the cooling system conduit for the transfer or heat therefrom.

  5. Bacterial diversity, community structure and function associated with biofilm development in a biological aerated filter in a recirculating marine aquaculture system

    Microsoft Academic Search

    Xi-Yan Gao; Yang Xu; Ying Liu; Zhi-Pei Liu

    A biological aerated filter (100 l), filled with bamboo ball media, was set up for treatment of low ammonia-containing recirculating\\u000a water in a marine aquaculture system. Chemical analysis showed that it took 70 days to establish a stable efficiency, at which\\u000a more than 30% of the ammonia was removed. During the biofilm development, bacterial diversity and community structure were\\u000a determined by construction

  6. The growth of disk abalone, Haliotis discus hannai at different culture densities in a pilot-scale recirculating aquaculture system with a baffled culture tank

    Microsoft Academic Search

    Hyung-Bae Kim; Pyong-Kih Kim; Jae-Yoon Jo

    2008-01-01

    The growth rate of disk abalone, Haliotis discus hannai, energy consumption and changes in water quality were monitored in a pilot-scale recirculating aquaculture system (RAS) for 155 days. Baffles were installed in the RAS culture tanks to enlarge the attachment area and clean out solid waste materials automatically by hydraulic force only. The experimental disk abalones, of shell length 24.5±0.5mm,

  7. Optimization and evaluation of a bottom substrate denitrification tank for nitrate removal from a recirculating aquaculture system.

    PubMed

    Pungrasmi, Wiboonluk; Playchoom, Cholticha; Powtongsook, Sorawit

    2013-08-01

    A bottom substrate denitrification tank for a recirculating aquaculture system was developed. The laboratory scale denitrification tank was an 8 L tank (0.04 m2 tank surface area), packed to a depth of 5 cm with a bottom substrate for natural denitrifying bacteria. An aquarium pump was used for gentle water mixing in the tank; the dissolved oxygen in the water was maintained in aerobic conditions (e.g. > 2 mg/L) while anoxic conditions predominated only at the bottom substrate layer. The results showed that, among the four substrates tested (soil, sand, pumice stone and vermiculite), pumice was the most preferable material. Comparing carbon supplementation using methanol and molasses, methanol was chosen as the carbon source because it provided a higher denitrification rate than molasses. When methanol was applied at the optimal COD:N ratio of 5:1, a nitrate removal rate of 4591 +/- 133 mg-N/m2 tank bottom area/day was achieved. Finally, nitrate removal using an 80 L denitrification tank was evaluated with a 610 L recirculating tilapia culture system. Nitrate treatment was performed by batch transferring high nitrate water from the nitrification tank into the denitrification tank and mixing with methanol at a COD:N ratio of 5:1. The results from five batches of nitrate treatment revealed that nitrate was successfully removed from water without the accumulation of nitrite and ammonia. The average nitrate removal efficiency was 85.17% and the average denitrification rate of the denitrification tank was 6311 +/- 945 mg-N/m2 tank bottom area/day or 126 +/- 18 mg-N/L of pumice packing volume/day. PMID:24520693

  8. Development and design of a fluidized bed/upflow sand filter configuration for use in recirculating aquaculture systems

    SciTech Connect

    Burden, D.G.

    1988-01-01

    A fluidized bed/upflow sand filter configuration, was developed and designed for utilization in recirculating aquaculture system, specifically the soft-shell crab and soft-shell crawfish industries. These filters were selected and designed because of their ability to withstand clogging and still maintain high levels of water quality for aquaculture production. The effectiveness of sand grain size was used to evaluate fluidized bed filter performance with filter loadings ranging from 16 to 1285 pounds of crawfish per cubic foot of filter sand. A coarse sand grain size was recommended as a filter media because of it's ability to shear excessive biofilm growth from the and, thus prohibiting clogging from occurring within the filter bed. The fluidized bed/upflow sand filter combination was evaluated in terms of nitrification and oxygen consumption when used with a recirculating crab shedding system. The filter combination's carrying capacity (700 crabs per cubic foot of sand media) exceeded that observed with the submerged rock filter by more than 20 times and was largely explained by the filter's solids removal ability which significantly reduced the filter's oxygen loading rate (OLR). Nitrification rates with the filter combination were extremely high as total ammonia and nitrite levels remained below 1.0 mg-N/l. Verification of a volumetric loading criteria (150 pounds per cubic foot) for this filter combination was further established with performance data obtained from a commercial soft-shell crawfish facility. Water quality monitoring results indicated that the filters maintained total ammonia and nitrite levels below 1.0 mg-N/l under typical operating conditions. Shock loading, pH control, and over-feeding, rather than filter capacity, dominated water quality fluctuations, thereby indicating that the loading criteria was sufficient for commercial operation.

  9. Advanced water iodinating system. [for potable water aboard manned spacecraft

    NASA Technical Reports Server (NTRS)

    Davenport, R. J.; Schubert, F. H.; Wynveen, R. A.

    1975-01-01

    Potable water stores aboard manned spacecraft must remain sterile. Suitable sterilization techniques are needed to prevent microbial growth. The development of an advanced water iodinating system for possible application to the shuttle orbiter and other advanced spacecraft, is considered. The AWIS provides a means of automatically dispensing iodine and controlling iodination levels in potable water stores. In a recirculation mode test, simulating application of the AWIS to a water management system of a long term six man capacity space mission, noniodinated feed water flowing at 32.2 cu cm min was iodinated to 5 + or - ppm concentrations after it was mixed with previously iodinated water recirculating through a potable water storage tank. Also, the AWIS was used to successfully demonstrate its capability to maintain potable water at a desired I2 concentration level while circulating through the water storage tank, but without the addition of noniodinated water.

  10. The ultra-high lime with aluminum process for removing chloride from recirculating cooling water 

    E-print Network

    Abdel-wahab, Ahmed Ibraheem Ali

    2004-09-30

    Chloride is a deleterious ionic species in cooling water systems because it is important in promoting corrosion. Chloride can be removed from cooling water by precipitation as calcium chloroaluminate using ultra-high lime ...

  11. The ultra-high lime with aluminum process for removing chloride from recirculating cooling water

    E-print Network

    Abdel-wahab, Ahmed Ibraheem Ali

    2004-09-30

    Chloride is a deleterious ionic species in cooling water systems because it is important in promoting corrosion. Chloride can be removed from cooling water by precipitation as calcium chloroaluminate using ultra-high lime with aluminum process (UHLA...

  12. Treatment of fishpond water by recirculating horizontal and vertical flow constructed wetlands in the tropics

    Microsoft Academic Search

    Dennis Konnerup; Ngo Thuy Diem Trang; Hans Brix

    2011-01-01

    Common practice of aquaculture in Vietnam and other countries in South East Asia involves frequent discharge of polluted water into rivers which results in eutrophication and degradation of receiving water bodies. There is therefore a need to develop improved aquaculture systems which have a more efficient use of water and less environmental impact. The aim of this study was to

  13. Electron recirculation in electrostatic multicusp systems: II. System performance scaling of one-dimensional rollover wells

    SciTech Connect

    Bussard, R.W.; King, K.E.

    1992-01-01

    In an earlier paper a comprehensive study was made of the recirculation and losses of electrons in their flow through simple inverse power-law potential wells bounded by similarly inverse power-law dependent magnetic fields. This study examined electron flow and loss behavior in the simplest approximation invoked to describe Polywell confinement systems. The importance of this study, and of the present paper, is that the power balance in Polywell systems is determined entirely by the rate of electron losses; if these are large, then the system can not yield net power. Thus it is of interest to determine those conditions that results in small losses, and to design experiments and systems to attempt to achieve and operate at these most favorable conditions, in order to test and prove the efficacy of the system for the generation of net power from fusion reactions. The outline and summary of this problem presented is generally repeated here, with some modifications to clarify particular physics issues of most concern, in order to avoid having to refer to the earlier document for this general description. As noted, a large body of work has been undertaken over the past 35 or so years in the study of general cusp confinement of plasmas. Nearly all of this has examined single particle electron (or ion) motion or the motion of particles in neutral plasmas within cusped magnetic systems, generally without internal electric potential fields.**INVALID KEYWORDS: controlled nuclear fusion, electron flux, plasma devices, confinement, performance, engineering, scaling factor, multicusp systems, polywell systems

  14. Characteristic time series and operation region of the system of two tank reactors (CSTR) with variable division of recirculation stream

    Microsoft Academic Search

    Henryk Merta

    2006-01-01

    The paper deals with a system of a cascade of two tank reactors, being characterized by the variable stream of recirculating fluid at each stage. The assumed mathematical model enables one to determine the system’s dynamics for the case when there is no time delay and for the opposite case. The time series of the conversion degree and of the

  15. Evaluation of depuration procedures to mitigate the off-flavor compounds geosmin and 2-methylisoborneol from Atlantic salmon Salmo salar raised to market-size in recirculating aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fish cultured within water recirculating aquaculture systems (RAS) can acquire “earthy” or “musty” off-flavors due to bioaccumulation of the compounds geosmin and 2-methylisoborneol (MIB), respectively, which are produced by certain bacterial species present in RAS biosolids and microbial biofilms. ...

  16. Changes in sex steroids, growth hormone, and insulin-like growth factor-I during ovarian development in Rainbow Trout cultured within a recirculating system with 24-hour Light

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Female rainbow trout (Onchorynchus mykiss) were cultured within a freshwater recirculating aquaculture system under 24-h constant lighting in 13oC water, and they were fed every six hours to near satiation. An opaque roof allowed surface light intensity to vary between <200 to ~1500 lx. Growth per...

  17. Characterization of the microbial community and nitrogen transformation processes associated with moving bed bioreactors in a closed recirculated mariculture system

    Microsoft Academic Search

    Yossi Tal; Joy E. M. Watts; Susan B. Schreier; Kevin R. Sowers; Harold J. Schreier

    2003-01-01

    The microbial consortium of a moving bed bioreactor (MBB) connected to a marine recirculating aquaculture system was examined by denaturing gradient gel electrophoresis (DGGE) of amplified 16S rRNA gene fragments. Both ammonia and nitrite oxidizers, Nitrosomonas cryotolerans and Nitrospira marina, respectively, were found associated with the marine system as well as a number of heterotrophic bacteria, including Pseudomonas sp. and

  18. Performance of a closed recirculating system with foam separation, nitrification and denitrification units for intensive culture of eel: towards zero emission

    Microsoft Academic Search

    Yoshihiro Suzuki; Toshiroh Maruyama; Hiroyuki Numata; Hajime Sato; Makio Asakawa

    2003-01-01

    The development of a closed recirculating aquaculture system that does not discharge effluents would reduce a large amount of pollutant load on aquatic bodies. In this study, eel were reared in a closed recirculating system, which consisted of a rearing tank, a foam separation unit, a nitrification unit and a denitrification unit. The foam separation unit has an inhalation-type aerator

  19. A system of air recirculation and antibacterial surface treatment in a surgical ward

    PubMed Central

    Ayliffe, G. A. J.; Beard, M. A.; Filbey, J.

    1962-01-01

    A system of surface treatment with an antibacterial agent and air recirculation through treated filters was set up in a 15-bedded surgical ward, using an adjacent 10-bedded ward as a control. Nasal, wound, and urinary cross-infection was studied in both wards for over one year. Total bacterial counts and counts of Staphylococcus pyogenes were made from settle plates and blanket sweep plates. After the installation of the system aerial contamination in the test ward was reduced appreciably more than in the control ward. The number of blankets contaminated with Staph. pyogenes was similar in both wards. There was no significant difference in wound, nasal, or urinary cross-infection between the two wards. PMID:13863501

  20. Comparison of aerobically-treated and untreated crop residue as a source of recycled nutrients in a recirculating hydroponic system

    NASA Technical Reports Server (NTRS)

    Mackowiak, C. L.; Garland, J. L.; Strayer, R. F.; Finger, B. W.; Wheeler, R. M.

    1996-01-01

    This study compared the growth of potato plants on nutrients recycled from inedible potato biomass. Plants were grown for 105 days in recirculating, thin-film hydroponic systems containing four separate nutrient solution treatments: (1) modified half-strength Hoagland's (control), 2) liquid effluent from a bioreactor containing inedible potato biomass, 3) filtered (0.2 micrometer) effluent, and 4) the water soluble fraction of inedible potato biomass (leachate). Approximately 50% of the total nutrient requirement in treatments 2-4 were provided (recycled) from the potato biomass. Leachate had an inhibitory effect on leaf conductance, photosynthetic rate, and growth (50% reduction in plant height and 60% reduction in tuber yield). Plants grown on bioreactor effluent (filtered or unfiltered) were similar to the control plants. These results indicated that rapidly degraded, water soluble organic material contained in the inedible biomass, i.e., material in leachate, brought about phytotoxicity in the hydroponic culture of potato. Recalcitrant, water soluble organic material accumulated in all nutrient recycling treatments (650% increase after 105 days), but no increase in rhizosphere microbial numbers was observed.

  1. High ratio recirculating gas compressor

    DOEpatents

    Weinbrecht, John F. (601 Oakwood Pl., NE., Albuquerque, NM 87123)

    1989-01-01

    A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor.

  2. High ratio recirculating gas compressor

    DOEpatents

    Weinbrecht, J.F.

    1989-08-22

    A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor. 10 figs.

  3. Production characteristics and body composition of juvenile cobia fed three different commercial diets in recirculating aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of feeding three commercial diets on production characteristics and body composition of juvenile cobia Rachycentron canadum reared using recirculating aquaculture systems (RAS) was evaluated in a 56 d growth trial. Juvenile cobia (29.2 +/= 0.7 g, mean weight +/= SE) were stocked into thr...

  4. Application of CFD modeling to hydrodynamics of CycloBio fluidized sand bed in recirculating aquaculture systems

    NASA Astrophysics Data System (ADS)

    Liu, Yao; Song, Xiefa; Liang, Zhenlin; Peng, Lei

    2013-11-01

    To improve the efficiency of a CycloBio fluidized sand bed (CB FSB) in removal of dissolved wastes in recirculating aquaculture systems, the hydrodynamics of solid-liquid flow was investigated using computational fluid dynamics (CFD) modeling tools. The dynamic characteristics of silica sand within the CB FSB were determined using three-dimensional, unsteady-state simulations with the granular Eulerian multiphase approach and the RNG k-? turbulence model, and the simulation results were validated using available lab-scale measurements. The bed expansion of CB FSB increased with the increase in water inflow rate in numerical simulations. Upon validation, the simulation involving 0.55 mm particles, the Gidaspow correlation for drag coefficient model and the Syamlal-O'Brien correlation for kinetic granular viscosity showed the closest match to the experimental results. The volume fraction of numerical simulations peaked as the wall was approached. The hydrodynamics of a pilot-scale CB FSB was simulated in order to predict the range of water flow to avoid the silica sand overflowing. The numerical simulations were in agreement with the experimental results qualitatively and quantitatively, and thus can be used to study the hydrodynamics of solid-liquid multiphase flow in CB FSB, which is of importance to the design, optimization, and amplification of CB FSBs.

  5. Depletion of florfenicol amine in tilapia (Oreochromis sp.) maintained in a recirculating aquaculture system following Aquaflor®-medicated feed therapy

    USGS Publications Warehouse

    Gaikowski, Mark P.; Whitsel, Melissa K.; Charles, Shawn; Schleis, Susan M.; Crouch, Louis S.; Endris, Richard G.

    2013-01-01

    Aquaflor® [50% w w?1 florfenicol (FFC)], is approved for use in freshwater-reared warmwater finfish which include tilapia Oreochromis spp. in the United States to control mortality from Streptococcus iniae. The depletion of florfenicol amine (FFA), the marker residue of FFC, was evaluated after feeding FFC-medicated feed to deliver a nominal 20 mg FFC kg?1 BW d?1 dose (1.33× the label use of 15 mg FFC kg?1 BW d?1) to Nile tilapia O. niloticus and hybrid tilapia O. niloticus × O. aureus held in a recirculating aquaculture system (RAS) at production-scale holding densities. Florfenicol amine concentrations were determined in fillets taken from 10 fish before dosing and from 20 fish at nine time points after dosing (from 1 to 240 h post-dosing). Water samples were assayed for FFC before, during and after the dosing period. Parameters monitored included daily feed consumption and biofilter function (levels of ammonia, nitrite and nitrate). Mean fillet FFA concentration decreased from 13.77 ?g g?1 at 1-h post dosing to 0.39 ?g g?1 at 240-h post dosing. Water FFC concentration decreased from a maximum of 1400 ng mL?1 at 1 day post-dosing to 847 ng mL?1 at 240 h post-dosing. There were no adverse effects noted on fish, feed consumption or biofilter function associated with FFC-medicated feed administration to tilapia.

  6. The design of an optimized portable artificial kidney system using recirculation and regeneration of dialysate.

    PubMed

    Bigsby, R J; Rider, R J; Blount, G N

    1998-01-01

    This paper is intended as an overview of the research carried out at Coventry University in the design of a portable artificial kidney system. It was seen that the key to the problem was the reduction in dialysate volume, and so it was decided to develop a prototype that would utilize the regeneration and recirculation of a small volume of dialysate. A prototype system has been produced and used to simulate a dialysis session. Activated carbon was used as a sorbent for the regeneration of the dialysate, circulating in a closed loop. For the purpose of this work, the adsorption of urea was investigated as this is, volumetrically, the major solute to be removed. Peltier effect cooling was used to vary the dialysate temperature down to 2 degrees C, as activated carbon will adsorb greater amounts of urea at lower temperatures. A series of tests was then carried out to investigate the effect of dialysate temperature, flowrate and volume on the amount of urea that could be dialysed. From the experimental results, a model of the system was derived, which made it possible to determine the implications of different operating conditions on the overall mass and size of a portable dialysis system. The output of this model was then used to establish a design specification and produce an optimum design solution for the system. PMID:9803156

  7. Development of high-efficiency molecular adsorbent recirculating system: preliminary report.

    PubMed

    Marangoni, Roberto; Bellati, Giorgio; Castelli, Alessandro; Romagnoli, Elisabetta

    2014-10-01

    Molecular Adsorbent Recirculating System (MARS) is a liver support system widely employed in the treatment of liver failure. The method is normally well tolerated. To develop a liver support system combining high efficiency and tolerability, we modified the MARS albumin circuit with the insertion of double adsorption units in parallel. Four patients have been treated with this modified method (high-efficiency MARS, HE MARS): two had very high serum bilirubin and two had very high total bile acids. After a single MARS session bilirubin was reduced more with HE MARS than standard MARS (from 27.6 to 52.3% in patient A and from 27.9 to 49.1% in patient B), and bile acid reduction increased from 40 to 59.8% in patient C and from 39.9 to 60% in patient D. The results of this preliminary investigation in only a very small number of patients do support the possibility of developing a liver support system that combines good tolerability and high efficacy. PMID:24392970

  8. Ozone (o3) efficacy on reduction of phytophthora capsici in recirculated horticultural irrigation water 

    E-print Network

    McDonald, Garry Vernon

    2009-05-15

    of the lamp surfaces. Another disadvantage to using UV radiation is a phenomenon known as photoreactivation and dark repair in which microorganisms have evolved biological systems to repair damage by sub-lethal exposure to disinfectants such as UV light... and cathode sources positioned on either side of a Nafion 117 (DuPont) proton-exchange 7 membrane (PEM), a fluoropolymer highly resistant to chemical degradation (Flusche, 2006). When water is fed to the anode (+) electrode, which is coated with lead...

  9. Improving methane production and phosphorus release in anaerobic digestion of particulate saline sludge from a brackish aquaculture recirculation system.

    PubMed

    Zhang, Xuedong; Ferreira, Rui B; Hu, Jianmei; Spanjers, Henri; van Lier, Jules B

    2014-06-01

    In this study, batch tests were conducted to examine the effects of trehalose and glycine betaine as well as potassium on the specific methanogenic activity (SMA), acid and alkaline phosphatase activity of anaerobic biomass and phosphorus release in anaerobic digestion of saline sludge from a brackish recirculation aquaculture system. The results of ANOVA and Tukey's HSD (honestly significant difference) tests showed that glycine betaine and trehalose enhanced SMA of anaerobic biomass and reactive phosphorus release from the particulate waste. Moreover, SMA tests revealed that methanogenic sludge, which was long-term acclimatized to a salinity level of 17 g/L was severely affected by the increase in salinity to values exceeding 35 g/L. Addition of compatible solutes, such as glycine betaine and trehalose, could be used to enhance the specific methane production rate and phosphorus release in anaerobic digestion from particulate organic waste produced in marine or brackish aquaculture recirculation systems. PMID:24785791

  10. Advanced Horizontal Well Recirculation Systems for Geothermal Energy Recovery in Sedimentary Formations

    SciTech Connect

    Mike Bruno; Russell L. Detwiler; Kang Lao; Vahid Serajian; Jean Elkhoury; Julia Diessl; Nicky White

    2012-09-30

    There is increased recognition that geothermal energy resources are more widespread than previously thought, with potential for providing a significant amount of sustainable clean energy worldwide. Recent advances in drilling, completion, and production technology from the oil and gas industry can now be applied to unlock vast new geothermal resources, with some estimates for potential electricity generation from geothermal energy now on the order of 2 million megawatts. Terralog USA, in collaboration with the University of California, Irvine (UCI), are currently investigating advanced design concepts for paired horizontal well recirculation systems, optimally configured for geothermal energy recovery in permeable sedimentary and crystalline formations of varying structure and material properties. This two-year research project, funded by the US Department of Energy, includes combined efforts for: 1) Resource characterization; 2) Small and large scale laboratory investigations; 3) Numerical simulation at both the laboratory and field scale; and 4) Engineering feasibility studies and economic evaluations. The research project is currently in its early stages. This paper summarizes our technical approach and preliminary findings related to potential resources, small-scale laboratory simulation, and supporting numerical simulation efforts.

  11. [Analysis of the changes of microbial community structure on bio-carrier of recirculating aquaculture systems (RAS)].

    PubMed

    Zhang, Hai-Geng; Ma, Shao-Sai; Li, Qiu-Fen; Fu, Xue-Jun; Zhang, Yan; Qu, Ke-Ming

    2011-01-01

    In order to study the variation of microbial community structure and the mechanism of denitrification on bio-carrier in recirculating aquaculture systems (RAS) during the periods of bio-film formation and operation the systems, traditional microbiological methods were applied to count the quantity of heterotrophic bacteria, ammonia oxidize bacteria and nitrite oxidize bacteria. The amplified products of variable V3 region of bacterial 16S rDNA were separated by using denaturing gradient gel electrophoresis (DGGE). And bacterial community DNA fingerprint was obtained. The sequences retrieved from the DGGE bands were used for homology analysis and construction of phylogenetic tree. It presented a trend that the quantity of the three types of bacteria increased gradually to a top and then fallen slowly to a stable level. The composition of microbial community of bio-carrier was very abundant in all periods, and the Shannon index was 1.53, 1.44, 1.57, 1.08, 1.27 and 1.30, respectively. During different periods, there was a certain shift in the microbial community structure, while the C(s) value (similar index) in two adjacent periods was high, indicating the variation and succession of the microbial community was slow and regular. Several bacteria had an effect on removal of pollutants for farming water and the effluent water quality could meet the requirements of high-density culture. Among them, Proteobacteria and Flavobacteria were main communities. The Nitrosomonas and some other facultative anaerobic bacteria (Flavobacteriaceae bacterium) were identified, which indicated that there may be coexisted pathways of nitrification and denitrification in bio-filter. PMID:21404692

  12. Production Characteristics and Body Composition of Juvenile Cobia Fed Three Different Commercial Diets in Recirculating Aquaculture Systems

    Microsoft Academic Search

    Charles R. Weirich; Paul S. Wills; Richard M. Baptiste; Marty A. Riche

    2010-01-01

    The effect of feeding three commercial diets on production characteristics and body composition of juvenile cobia Rachycentron canadum reared using recirculating aquaculture systems (RASs) was assessed in a 56-d growth trial. Juvenile cobia (mean weight ± SE, 29.2 ± 0.7 g) were stocked into three 8-m tanks in each of four RASs at an initial density of 1.2 kg\\/m. After

  13. Effects of Biofilter\\/Culture Tank Volume Ratios on Productivity of a Recirculating Fish\\/Vegetable Co-Culture System

    Microsoft Academic Search

    M. R. McMurtry; D. C. Sanders; J. D. Cure; R. G. Hodson

    1997-01-01

    The effects of four biofilter volume (BFV)\\/culture tank volume ratios (0.67\\/1, 1.00\\/1, 1.50\\/1, and 2.25\\/1) on biofilter function were examined in a recirculating fish\\/vegetable production system in a greenhouse. Sand beds served as biofilters, as substrate for vegetable growth, and as location for decomposition of waste solids. No fertilizer was used. Three experiments were conducted over the course of one

  14. Anaerobic Ammonium-Oxidizing (Anammox) Bacteria and Associated Activity in Fixed-Film Biofilters of a Marine Recirculating Aquaculture System

    Microsoft Academic Search

    Yossi Tal; Joy E. M. Watts; Harold J. Schreier

    2006-01-01

    Microbial communities in the biological filter and waste sludge compartments of a marine recirculating aqua- culture system were examined to determine the presence and activity of anaerobic ammonium-oxidizing (anammox) bacteria. Community DNA was extracted from aerobic and anaerobic fixed-film biofilters and the anaerobic sludge waste collection tank and was analyzed by amplifying 16S rRNA genes by PCR using anammox-selective and

  15. Recirculating pump seal investigation. Final report. Volume 1

    Microsoft Academic Search

    1977-01-01

    This report presents the results of a review of experience with reactor coolant and recirculating pump seal designs and pump seal auxiliary systems. The scope of this review includes all operating commercial light water reactors (LWRs) over 400 MWe in the United States. Problems which have been encountered with seals and seal auxiliary systems are discussed, the principal causes of

  16. Water Quality Monitoring in a Pilot Marine Integrated Aquaculture System

    Microsoft Academic Search

    Alex W. Kruglick

    2012-01-01

    Land based aquaculture systems are growing in popularity, and there is a drive to improve the efficiency of their energy and water systems for both economic and environmental benefit. Recirculating Aquaculture Systems (RAS) generally refer to systems that recycle their wastewater streams to be more or less a zero discharge facility. A more sustainable approach is emerging in the form

  17. Two-dimensional hydraulics of recirculating ground-water remediation wells in unconfined aquifers

    SciTech Connect

    Stallard, W.M. [Stallard (W.M.), Sacramento, CA (United States); Wu, K.C.; Shi, N.; Corapcioglu, M.Y. [Texas A and M Univ., College Station, TX (United States). Dept. of Civil Engineering

    1996-08-01

    A technique for remediating and protecting ground-water and drinking-water wells from contamination is presented. A ground-water remediation well design is proposed in which ground water is drawn into the well bottom, treated in the well casing, and returned clean to the aquifer at the well top. The hydraulics of ground-water circulation around imperfectly penetrating wells were examined experimentally in pilot-scale tanks and mathematically with numerical models in a two-dimensional domain. Ambient ground-water velocities of from 1 to 3 m/day, typical for coarse sand and gravel aquifers, were simulated in combination with in-well vertical velocities of from 2 to 16 m/day. Under some of these flow conditions, contaminants were intercepted and drawn into the wells for treatment. Hydraulic problems identified with the experimental apparatus and simulated by the computer models included blow through of contaminant at the well intake by high ambient ground-water velocities and submergence by the well hydraulics of surface contaminant plumes without interception. Both types of problems were corrected by adjusting internal well velocities. Important design parameters include ambient ground-water velocity and well pumping rate.

  18. Recirculation of process water in the production of ethanol from softwood

    Microsoft Academic Search

    Mats Larsson; Mats Galbe; Guido Zacchi

    1997-01-01

    In the production of ethanol from lignocellulosics, large quantities of water are needed in various process steps. In industrial processes, recycling of process streams is necessary to minimise fresh water requirements and decrease the amount of wastewater produced. This leads to increases in various substances, both volatile and non-volatile, which inhibit fermentation. In the present study ethanol was produced from

  19. Bacterially mediated removal of phosphorus and cycling of nitrate and sulfate in the waste stream of a "zero-discharge" recirculating mariculture system.

    PubMed

    Krom, M D; Ben David, A; Ingall, E D; Benning, L G; Clerici, S; Bottrell, S; Davies, C; Potts, N J; Mortimer, R J G; van Rijn, J

    2014-06-01

    Simultaneous removal of nitrogen and phosphorus by microbial biofilters has been used in a variety of water treatment systems including treatment systems in aquaculture. In this study, phosphorus, nitrate and sulfate cycling in the anaerobic loop of a zero-discharge, recirculating mariculture system was investigated using detailed geochemical measurements in the sludge layer of the digestion basin. High concentrations of nitrate and sulfate, circulating in the overlying water (?15 mM), were removed by microbial respiration in the sludge resulting in a sulfide accumulation of up to 3 mM. Modelling of the observed S and O isotopic ratios in the surface sludge suggested that, with time, major respiration processes shifted from heterotrophic nitrate and sulfate reduction to autotrophic nitrate reduction. The much higher inorganic P content of the sludge relative to the fish feces is attributed to conversion of organic P to authigenic apatite. This conclusion is supported by: (a) X-ray diffraction analyses, which pointed to an accumulation of a calcium phosphate mineral phase that was different from P phases found in the feces, (b) the calculation that the pore waters of the sludge were highly oversaturated with respect to hydroxyapatite (saturation index = 4.87) and (c) there was a decrease in phosphate (and in the Ca/Na molar ratio) in the pore waters simultaneous with an increase in ammonia showing there had to be an additional P removal process at the same time as the heterotrophic breakdown of organic matter. PMID:24657541

  20. Anaerobic Ammonium-Oxidizing (Anammox) Bacteria and Associated Activity in Fixed-Film Biofilters of a Marine Recirculating Aquaculture System

    PubMed Central

    Tal, Yossi; Watts, Joy E. M.; Schreier, Harold J.

    2006-01-01

    Microbial communities in the biological filter and waste sludge compartments of a marine recirculating aquaculture system were examined to determine the presence and activity of anaerobic ammonium-oxidizing (anammox) bacteria. Community DNA was extracted from aerobic and anaerobic fixed-film biofilters and the anaerobic sludge waste collection tank and was analyzed by amplifying 16S rRNA genes by PCR using anammox-selective and universal GC-clamped primers. Separation of amplified PCR products by denaturing gradient gel electrophoresis and sequencing of the different phylotypes revealed a diverse biofilter microbial community. While Planctomycetales were found in all three communities, the anaerobic denitrifying biofilters contained one clone that exhibited high levels of sequence similarity to known anammox bacteria. Fluorescence in situ hybridization studies using an anammox-specific probe confirmed the presence of anammox Planctomycetales in the microbial biofilm from the denitrifying biofilters, and anammox activity was observed in these biofilters, as detected by the ability to simultaneously consume ammonia and nitrite. To our knowledge, this is the first identification of anammox-related sequences in a marine recirculating aquaculture filtration system, and our findings provide a foundation for incorporating this important pathway for complete nitrogen removal in such systems. PMID:16597996

  1. Removal of naphthalene from recirculated wash oil

    SciTech Connect

    Burcaw, K.R.; Watkins, R.E.

    1981-09-01

    A bleed stream from the recirculating wash oil in a final cooling system for coke oven gas is centrifugally separated into a waste water stream, a sludge stream and a clean, dry oil stream which is substantially free of solids and has a water content less than 0.5% (Wt.). The clean, dry oil stream is heated to less than about 160/sup 0/C., preferably 125/sup 0/-135/sup 0/C, before entering a naphthalene stripper-wash oil still.

  2. Un formalisme de systemes a sauts pour la recirculation optimale des casses dans une machine a papier

    NASA Astrophysics Data System (ADS)

    Khanbaghi, Maryam

    Increasing closure of white water circuits is making mill productivity and quality of paper produced increasingly affected by the occurrence of paper breaks. In this thesis the main objective is the development of white water and broke recirculation policies. The thesis consists of three main parts, respectively corresponding to the synthesis of a statistical model of paper breaks in a paper mill, the basic mathematical setup for the formulation of white water and broke recirculation policies in the mill as a jump linear quadratic regulation problem, and finally the tuning of the control law based on first passage-time theory, and its extension to the case of control sensitive paper break rates. More specifically, in the first part a statistical model of paper machine breaks is developed. We start from the hypothesis that the breaks process is a Markov chain with three states: the first state is the operational one, while the two others are associated with the general types of paper-breaks that can take place in the mill (wet breaks and dry breaks). The Markovian hypothesis is empirically validated. We also establish how paper-break rates are correlated with machine speed and broke recirculation ratio. Subsequently, we show how the obtained Markov chain model of paper-breaks can be used to formulate a machine operating speed parameter optimization problem. In the second part, upon recognizing that paper breaks can be modelled as a Markov chain type of process which, when interacting with the continuous mill dynamics, yields a jump Markov model, jump linear theory is proposed as a means of constructing white water and broke recirculation strategies which minimize process variability. Reduced process variability comes at the expense of relatively large swings in white water and broke tanks level. Since the linear design does not specifically account for constraints on the state-space, under the resulting law, damaging events of tank overflow or emptiness can occur. A heuristic simulation-based approach is proposed to choose the performance measure design parameters to keep the mean time between incidents of fluid in broke and white water tanks either overflowing, or reaching dangerously low levels, sufficiently long. In the third part, a methodology, mainly founded on the first passage-time theory of stochastic processes, is proposed to choose the performance measure design parameters to limit process variability while accounting for the possibility of undesirable tank overflows or tank emptiness. The heart of the approach is an approximation technique for evaluating mean first passage-times of the controlled tanks levels. This technique appears to have an applicability which largely exceeds the problem area it was designed for. Furthermore, the introduction of control sensitive break rates and the analysis of the ensuing control problem are presented. This is to account for the experimentally observed increase in breaks concomitant with flow rate variability.

  3. Phosphatase activity and specific methanogenic activity in an anaerobic reactor treating sludge from a brackish recirculation aquaculture system.

    PubMed

    Zhang, Xuedong; Ferreira, Rui B; Spanjers, Henri; van Lier, Jules B

    2013-01-01

    Anaerobic treatment of high salinity sludge from marine/brackish recirculation aquaculture systems is potentially limited by inhibition of enzymatic activities and cell lysis resulting from high osmotic pressures. To further address these limitations the following investigations were conducted: effect of salinity on phosphatase activity (PA), soluble microbial products (SMP) production, and presence of extracellular polymeric substances (EPS); effect of iron (III) chloride (FeCl3) on PA and specific methanogenic activity (SMA); effect of addition of the compatible solute glycine betaine (GB) and potassium on PA, as well as on SMP and EPS production, all under saline conditions. The results show that salinity has different effects on PA of anaerobes under starvation and feeding conditions. FeCl3 increased the SMA of the sludge by 22.5% at 100 mg FeCl3/L compared with a control group (0 mg FeCl3/L). Furthermore, results of analysis of variance tests show that betaine increased the polysaccharide content of EPS and polypeptide content of SMP. However, addition of 1 mM potassium chloride did not show a significant effect on EPS and SMP composition. In conclusion, anaerobic digestion of salty sludges from a brackish aquaculture recirculation system may not be negatively affected by FeCl3 addition to concentrate waste streams, whereas GB boosts the production of SMP and EPS. PMID:23863432

  4. Impact of depuration of earth-musty off-flavors on fillet quality of atlantic salmon, Salmo salar, cultured in a recirculating aquaculture system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the past decade in the United States, there has been increased interest in the establishment and use of land-based, closed-containment systems [e.g., recirculating aquaculture system (RAS)] for salmonid culture. These culture systems have unique challenges compared to net pen culture of salmon...

  5. Impact of depuration of earthy-musty off-flavors on fillet quality of Atlantic salmon, Salmo salar, cultured in a recirculating system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the past decade in the United States, there has been increased interest in the establishment and use of land-based, closed-containment systems [e.g., recirculating aquaculture system (RAS)] for salmonid culture. These culture systems have unique challenges compared to net pen culture of salmon...

  6. Particle sieve analysis for solids removal efficiency for recirculating aquaculture system components

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As the aquaculture industry develops, opportunites for small-scale farms to become an integral part of the industry will become more prevalent. For small-scale operations it is important to have a system design that is efficient in water and energy use. If such operations decide to utilize recircula...

  7. Implementation of an experimental pilot reproducing the fouling of the exhaust gas recirculation system in diesel engines

    NASA Astrophysics Data System (ADS)

    Gaborieau, Cécile; Sommier, Alain; Toutain, Jean; Anguy, Yannick; Crepeau, Gérald; Gobin, Benoît

    2012-04-01

    The European emission standards EURO 5 and EURO 6 define more stringent acceptable limits for exhaust emissions of new vehicles. The Exhaust Gas Recirculation (EGR) system is a partial but essential solution for lowering the emission of nitrogen oxides and soot particulates. Yet, due to a more intensive use than in the past, the fouling of the EGR system is increased. Ensuring the reliability of the EGR system becomes a main challenge. In partnership with PSA Peugeot Citroën, we designed an experimental setup that mimics an operating EGR system. Its distinctive features are (1) its ability to reproduce precisely the operating conditions and (2) its ability to measure the temperature field on the heat exchanger surface with an Infra Red camera for detecting in real time the evolution of the fooling deposit based on its thermal resistance. Numerical codes are used in conjunction with this experimental setup to determine the evolution of the fouling thickness from its thermal resistance.

  8. Role of Hot Water System Design on Factors Influential to Pathogen Regrowth: Temperature, Chlorine Residual, Hydrogen Evolution, and Sediment

    PubMed Central

    Brazeau, Randi H.; Edwards, Marc A.

    2013-01-01

    Abstract Residential water heating is linked to growth of pathogens in premise plumbing, which is the primary source of waterborne disease in the United States. Temperature and disinfectant residual are critical factors controlling increased concentration of pathogens, but understanding of how each factor varies in different water heater configurations is lacking. A direct comparative study of electric water heater systems was conducted to evaluate temporal variations in temperature and water quality parameters including dissolved oxygen levels, hydrogen evolution, total and soluble metal concentrations, and disinfectant decay. Recirculation tanks had much greater volumes of water at temperature ranges with potential for increased pathogen growth when set at 49°C compared with standard tank systems without recirculation. In contrast, when set at the higher end of acceptable ranges (i.e., 60°C), this relationship was reversed and recirculation systems had less volume of water at risk for pathogen growth compared with conventional systems. Recirculation tanks also tended to have much lower levels of disinfectant residual (standard systems had 40–600% higher residual), 4–6 times as much hydrogen, and 3–20 times more sediment compared with standard tanks without recirculation. On demand tankless systems had very small volumes of water at risk and relatively high levels of disinfectant residual. Recirculation systems may have distinct advantages in controlling pathogens via thermal disinfection if set at 60°C, but these systems have lower levels of disinfectant residual and greater volumes at risk if set at lower temperatures. PMID:24170969

  9. 40 CFR 1065.127 - Exhaust gas recirculation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Exhaust gas recirculation. Use the exhaust gas recirculation (EGR) system installed with the engine or one that represents a typical in-use configuration. This includes any applicable EGR cooling...

  10. Temperature effects on biomass, geosmin, and 2-methylisoborneol production and cellular activity by Nocardia spp. and Streptomyces spp. isolated from rainbow trout recirculating aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Isolates of Nocardia cummidelens, Nocardia fluminea, Streptomyces albidoflavus, and Streptomyces luridiscabiei attributing to geosmin-related off-flavor in rainbow trout (Oncorhynchus mykiss) raised in recirculating aquaculture systems (RAS) were evaluated for the effect of temperature (10-30 degree...

  11. Molecular Analysis of Bacterial Communities and Detection of Potential Pathogens in a Recirculating Aquaculture System for Scophthalmus maximus and Solea senegalensis

    PubMed Central

    Martins, Patrícia; Cleary, Daniel F. R.; Pires, Ana C. C.; Rodrigues, Ana Maria; Quintino, Victor; Calado, Ricardo; Gomes, Newton C. M.

    2013-01-01

    The present study combined a DGGE and barcoded 16S rRNA pyrosequencing approach to assess bacterial composition in the water of a recirculating aquaculture system (RAS) with a shallow raceway system (SRS) for turbot (Scophthalmus maximus) and sole (Solea senegalensis). Barcoded pyrosequencing results were also used to determine the potential pathogen load in the RAS studied. Samples were collected from the water supply pipeline (Sup), fish production tanks (Pro), sedimentation filter (Sed), biofilter tank (Bio), and protein skimmer (Ozo; also used as an ozone reaction chamber) of twin RAS operating in parallel (one for each fish species). Our results revealed pronounced differences in bacterial community composition between turbot and sole RAS, suggesting that in the systems studied there is a strong species-specific effect on water bacterial communities. Proteobacteria was the most abundant phylum in the water supply and all RAS compartments. Other important taxonomic groups included the phylum Bacteriodetes. The saltwater supplied displayed a markedly lower richness and appeared to have very little influence on bacterial composition. The following potentially pathogenic species were detected: Photobacterium damselae in turbot (all compartments), Tenacibaculum discolor in turbot and sole (all compartments), Tenacibaculum soleae in turbot (all compartments) and sole (Pro, Sed and Bio), and Serratia marcescens in turbot (Sup, Sed, Bio and Ozo) and sole (only Sed) RAS. Despite the presence of these pathogens, no symptomatic fish were observed. Although we were able to identify potential pathogens, this approach should be employed with caution when monitoring aquaculture systems, as the required phylogenetic resolution for reliable identification of pathogens may not always be possible to achieve when employing 16S rRNA gene fragments. PMID:24278329

  12. Molecular adsorbent recirculating system is ineffective in the management of type 1 hepatorenal syndrome in patients with cirrhosis with ascites who have failed vasoconstrictor treatment

    Microsoft Academic Search

    Florence Wong; Nilima Raina; Robert Richardson

    2009-01-01

    BackgroundThe pathogenetic mechanism of hepatorenal syndrome (HRS) is paradoxical renal vasoconstriction consequent upon systemic and splanchnic arterial vasodilatation. Molecular adsorbent recirculating system (MARS) is a specialised form of dialysis that clears albumin-bound substances, including vasodilators, and therefore can potentially reduce systemic vasodilatation in cirrhosis.ObjectiveTo assess the efficacy of MARS in improving systemic and renal haemodynamics in patients with cirrhosis with

  13. Comparison of a fuel-driven and steam-driven ejector in solid oxide fuel cell systems with anode off-gas recirculation: Part-load behavior

    NASA Astrophysics Data System (ADS)

    Engelbracht, Maximilian; Peters, Roland; Blum, Ludger; Stolten, Detlef

    2015-03-01

    This paper investigates the use of ejectors for recirculating anode off-gas in an SOFC system, focusing on the part-load capability of two different systems. In the first system, recirculation was enabled by a fuel-driven ejector. The part-load threshold of this system was determined by carbon formation and was 77.8% assuming a fuel utilization of 70% and suitable ejector geometry. The second system was based on a steam-driven ejector. The simulation results for this system showed an improved part-load capability of 37.8% as well as a slightly improved electrical efficiency. Here, the minimal part load was determined by the condensation temperature of the condenser used in the system.

  14. Comparative performance of CO2 measuring methods: marine aquaculture recirculation system application

    USGS Publications Warehouse

    Pfeiffer, T.J.; Summerfelt, S.T.; Watten, B.J.

    2011-01-01

    Many methods are available for the measurement of dissolved carbon dioxide in an aqueous environment. Standard titration is the typical field method for measuring dissolved CO2 in aquaculture systems. However, titrimetric determination of dissolved CO2 in marine water aquaculture systems is unsuitable because of the high dissolved solids, silicates, and other dissolved minerals that interfere with the determination. Other methods used to measure dissolved carbon dioxide in an aquaculture water included use of a wetted CO2 probe analyzer, standard nomographic methods, and calculation by direct measurements of the water's pH, temperature, and alkalinity. The determination of dissolved CO2 in saltwater based on partial pressure measurements and non-dispersive infra-red (NDIR) techniques with a CO2 gas analyzer are widely employed for oceanic surveys of surface ocean CO2 flux and are similar to the techniques employed with the head space unit (HSU) in this study. Dissolved carbon dioxide (DC) determination with the HSU using a infra-red gas analyzer (IRGA) was compared with titrimetric, nomographic, calculated, and probe measurements of CO2 in freshwater and in saltwater with a salinity ranging from 5.0 to 30 ppt, and a CO2 range from 8 to 50 mg/L. Differences in CO2 measurements between duplicate HSUs (0.1–0.2 mg/L) were not statistically significant different. The coefficient of variation for the HSU readings averaged 1.85% which was better than the CO2 probe (4.09%) and that for the titrimetric method (5.84%). In all low, medium and high salinity level trials HSU precision was good, averaging 3.39%. Differences existed between comparison testing of the CO2 probe and HSU measurements with the CO2 probe readings, on average, providing DC estimates that were higher than HSU estimates. Differences between HSU and titration based estimates of DC increased with salinity and reached a maximum at 32.2 ppt. These differences were statistically significant (P < 0.05) at all salinity levels greater than 0.3 ppt. Results indicated reliable replicated results from the head space unit with varying salinity and dissolved carbon dioxide concentrations.

  15. Gas transfer rates from airlifts used for concurrent aeration, carbon dioxide stripping, and recirculation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Airlifts simplify recirculating aquaculture systems and can potentially reduce capital costs and minimize maintenance issues. Airlifts have the ability to move and aerate water as well as degass the water of any carbon dioxide. This study evaluated the oxygen transfer and carbon dioxide removal abil...

  16. Water Systems

    NSDL National Science Digital Library

    Water cycle concepts and basics including the distribution of water on the planet in oceans, rivers and lakes, glaciers and atmosphere. Defines basic terms: states of water, evaporation, transpiration, condensation, precipitation, melting. Good illustrations, maps and photos. Excellent list itemizes human uses and impacts on water and the water cycle. Links to more detailed references are provided, case studies illustrate current concerns and issues in Ontario, Canada.

  17. Peracetic acid degradation and effects on nitrification in recirculating aquaculture systems

    Microsoft Academic Search

    Lars-Flemming Pedersen; Per B. Pedersen; Jeppe L. Nielsen; Per H. Nielsen

    2009-01-01

    Peracetic acid (PAA) is a powerful disinfectant with a wide spectrum of antimicrobial activity. PAA and hydrogen peroxide (HP) degrade easily to oxygen and water and have potential to replace formalin in aquaculture applications to control fish pathogens, for example the ectoparasite, Ichthyophthirius multifiliis.We studied water phase PAA and HP decay in three aquaculture situations, i) batch experiments with two

  18. Modeling and design of a ultraviolet disinfection reactor for air recirculation systems

    Microsoft Academic Search

    Soojung Lim

    2010-01-01

    It is well established that many pathogenic microorganisms can reside in water. Similarly, many microbial pathogens can be suspended in air. However, disinfection processes for air are generally not as well developed as those for water. In situations involving groups of people in confined space, such as class rooms, surgery rooms, and airplane cabins, a shared air space provides opportunities

  19. Temperature effects on biomass, geosmin, and 2-methylisoborneol production and cellular activity by Nocardia spp. and Streptomyces spp. isolated from rainbow trout recirculating aquaculture systems.

    PubMed

    Schrader, Kevin K; Harries, Marcuslene D; Page, Phaedra N

    2015-05-01

    Isolates of Nocardia cummidelens, Nocard ia fluminea, Streptomyces albidoflavus, and Streptomyces luridiscabiei attributed as the cause of "earthy-musty" off-flavor in rainbow trout (Oncorhynchus mykiss) raised in recirculating aquaculture systems (RAS) were evaluated for the effect of temperature (10-30 °C) on biomass, geosmin, and 2-methylisoborneol (MIB) production and cellular activity. Cultures of these isolates were monitored over 7 days by measuring culture dry weight, geosmin, and MIB production using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS), and ATP production via a luminometer. Compared to the other isolates, S. luridiscabiei had significantly (P < 0.05) higher biomass (8.17 ± 0.35 mg/mL) at 15 °C (water temperature in the RAS) after 7 days incubation. In addition, S. luridiscabiei produced significantly (P < 0.05) higher geosmin (69,976 ± 15,733 ng/L) at 15 °C. At 25 °C and 30 °C, S. albidoflavus produced significantly (P < 0.05) higher geosmin (182,074 ± 60,272 ng/L and 399,991 ± 102,262 ng/L, respectively). All isolates produced MIB at 15 °C, but S. luridiscabiei produced significantly (P < 0.05) higher MIB (97,143 ± 28,972 ng/L) and ATP after 7 days. Therefore, S. luridiscabiei appears to be a likely contributor of geosmin and MIB in the RAS. PMID:25724337

  20. Biological denitrification using poly(butylene succinate) as carbon source and biofilm carrier for recirculating aquaculture system effluent treatment.

    PubMed

    Zhu, Song-Ming; Deng, Ya-Le; Ruan, Yun-Jie; Guo, Xi-Shan; Shi, Ming-Ming; Shen, Jia-Zheng

    2015-09-01

    Nitrate removal is essential for the sustainable operation of recirculating aquaculture system (RAS). This study evaluated the heterotrophic denitrification using poly(butylene succinate) as carbon source and biofilm carrier for RAS wastewater treatment. The effect of varied operational conditions (influent type, salinity and nitrate loading) on reactor performance and microbial community was investigated. The high denitrification rates of 0.53±0.19kgNO3(-)-Nm(-3)d(-1) (salinity, 0‰) and 0.66±0.12kgNO3(-)-Nm(-3)d(-1) (salinity, 25‰) were achieved, and nitrite concentration was maintained below 1mg/L. In addition, the existence of salinity exhibited more stable nitrate removal efficiency, but caused adverse effects such as excessive effluent dissolved organic carbon (DOC) and dissimilation nitrate reduce to ammonia (DNRA) activity. The degradation of PBS was further confirmed by SEM and FTIR analysis. Illumina sequencing revealed the abundance and species changes of functional denitrification and degradation microflora which might be the primary cause of varied reactor performance. PMID:26093254

  1. Nitrification performance of a bubble-washed bead filter for combined solids removal and biological filtration in a recirculating aquaculture system

    Microsoft Academic Search

    Balaji N Sastry; Aurelio A DeLosReyes Jr; Kelly A Rusch; Ronald F Malone

    1999-01-01

    Laboratory studies were conducted to evaluate the nitrification performance of a bubble-washed bead filter as affected by backwashing frequency and feed loading rate. The bubble-washed bead filter was used for combined solids capture and biological filtration in a recirculating tilapia (Oreochromis niloticus) culture system. The filter was tested at feed loading rates of 16, 24, and 32 kg day?1 m?3

  2. The trapping system for the recirculated gases at different locations of the exhaust gas recirculation (EGR) pipe of a homogeneous charge compression ignition (HCCI) engine

    NASA Astrophysics Data System (ADS)

    Piperel, A.; Montagne, X.; Dagaut, P.

    2008-10-01

    Nowadays, in diesel engines, it is typical to recycle exhaust gases (EGR) in order to decrease pollutant emissions. However, few studies report the precisely measured composition of the recycled gases. Indeed, in order to know precisely the composition of the EGR gases, they have to be sampled hot and not diluted, in contrast to the usual practice. Thus, a new system to collect such samples was developed. With this new trapping system, it is possible to measure the concentrations of NOx, CO, CO2, O2, hydrocarbons (HCs) in the range C1-C9, aldehydes, ketones and PAHs. The trapping system and the analytical protocol used are described in this paper.

  3. Are restricted periods of over-stocking of recirculating aquaculture systems advisable? A simulation study

    Microsoft Academic Search

    Ido Seginer

    2009-01-01

    Fish stocking is an important element of aquaculture management. A constant stocking rate is a convenient strategy in intensive aquaculture, being also the best under steady physical and economic conditions. If, however, these conditions vary with time, the best stocking rate may also vary. This problem has been addressed in a previous paper, where water temperature, fish price and\\/or market

  4. Recirculating rotary gas compressor

    DOEpatents

    Weinbrecht, John F. (601 Oakwood Loop, NE., Albuquerque, NM 87123)

    1992-01-01

    A positive displacement, recirculating Roots-type rotary gas compressor which operates on the basis of flow work compression. The compressor includes a pair of large diameter recirculation conduits (24 and 26) which return compressed discharge gas to the compressor housing (14), where it is mixed with low pressure inlet gas, thereby minimizing adiabatic heating of the gas. The compressor includes a pair of involutely lobed impellers (10 and 12) and an associated port configuration which together result in uninterrupted flow of recirculation gas. The large diameter recirculation conduits equalize gas flow velocities within the compressor and minimize gas flow losses. The compressor is particularly suited to applications requiring sustained operation at higher gas compression ratios than have previously been feasible with rotary pumps, and is particularly applicable to refrigeration or other applications requiring condensation of a vapor.

  5. Solids removal in a recirculating aquaculture system where the majority of flow bypasses the microscreen filter

    Microsoft Academic Search

    Robert C. Summerfelt; Chris R. Penne

    2005-01-01

    Solids capture in a sedimentation basin in the lower portion of an external standpipe was compared with solids capture by the drum filter (DF) in a commercial recycle aquaculture system (RAS) with dual-drain culture tanks equipped with sidewall and bottom-center drains. The system had a unique combination of features: sidewall drain effluent, 79% of total from the culture tank, that

  6. The Role of Water Chemistry in Marine Aquarium Design: A Model System for a General Chemistry Class

    Microsoft Academic Search

    Jeffrey J. Keaffaber; Ramiro Palma; Kathryn R. Williams

    2008-01-01

    Water chemistry is central to aquarium design, and it provides many potential applications for discussion in undergraduate chemistry and engineering courses. Marine aquaria and their life support systems feature many chemical processes. A life support system consists of the entire recirculation system, as well as the habitat tank and all ancillary water treatment processes. Many fundamental concepts learned in general

  7. Stocking density effects on production characteristics and body composition of market size cobia, Rachycentron canadum, reared in recirculating aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Production density in excess of a critical threshold can result in a negative relationship between stocking density and fish production. This study was conducted to evaluate production characteristics of juvenile cobia Rachycentron canadum, reared to market size in production-scale recirculating aq...

  8. Electron recirculation in electrostatic multicusp systems: 1. Confinement and losses in simple power law wells

    Microsoft Academic Search

    R. W. Bussard; K. E. King

    1991-01-01

    A large body of work over the past 35 years has been devoted to the study of cusp confinement of electrons, ions, and plasmas. Nearly all of this has examined single particle electron (or ion) motion or the motion of particles in neutral plasmas within cusped magnetic systems, generally without internal electric potential fields. In this note the problem of

  9. Culture of selected organisms in recirculating and flow-through systems using thermal effluent

    E-print Network

    Berry, Terri Layne

    1978-01-01

    studies from January to May 1977. Fish were transported from collection site in an oxygenated 984-liter fiberglass hauling tank (Hurley Fiber- glass Company, Newport, Arkansas). American oysters were collected by hand at low tide from a reef north... for all species and condition, food conversion and percent efficiency of feed utilization of fish were computed at each sampling period. Polyculture of oysters with fish in the flow- through system did not adversely affect growth or survival...

  10. Culture of selected organisms in recirculating and flow-through systems using thermal effluent 

    E-print Network

    Berry, Terri Layne

    1978-01-01

    in the greenhouse laboratory. Major species American oyster Pinfish Atlantic croaker Atlantic spadefish White mullet dlinor species C t La odon r!jomboides go d 1 t Chaetodipterus f aber ~51ucp c u rema Sea catfish Spot Red drum Arius felis... setiferus ~ecealops atlantica ~C' do ~t -* '1' ~lt' L tj d L tl Lobo tes surinamensis Archosargus probatocephalus Pogonias cromis -' 1 ~tl ~ld t 1 o to systems were stocked with 20 oysters and no fish. All oysters were suspend~ d . in 45 x 33 x 10-c...

  11. A mathematical model for a parallel plate electrochemical reactor, CSTR, and associated recirculation system 

    E-print Network

    Nguyen, Trung Van

    1985-01-01

    oz 10) D, dt 11) 8, , m, g(t&g = 1) rt & 1 (Outlet) and t ) 0 et8, Bz8, -, F /-oz BC tizzy& 88t 84 I -r 8, ? ?? ? '? 8, a?z ' ftT[~, a, d, z aq a?j rl = 6J (u ? q')8t(t, q. t = I)dq 12) Qzc, ?f8, = 0 For 0 & rt & 1 and 0 & C & 1 for t & 0... the IAD technique is implemented for an unsteady state ER system. the following grid diagrams are included: implicit in axial (f) direction (ER-model) rt = 0 (anode) II3l! K41. ' 0 & rt & 1 (channel) (f = 0) (& = &) rt = 1 (cathode) 8;=8, and 4 =4...

  12. Residential hot water distribution systems: Roundtablesession

    SciTech Connect

    Lutz, James D.; Klein, Gary; Springer, David; Howard, Bion D.

    2002-08-01

    Residential building practice currently ignores the lossesof energy and water caused by the poor design of hot water systems. Theselosses include: combustion and standby losses from water heaters, thewaste of water (and energy) while waiting for hot water to get to thepoint of use; the wasted heat as water cools down in the distributionsystem after a draw; heat losses from recirculation systems and thediscarded warmth of waste water as it runs down the drain. Severaltechnologies are available that save energy (and water) by reducing theselosses or by passively recovering heat from wastewater streams and othersources. Energy savings from some individual technologies are reported tobe as much as 30 percent. Savings calculations of prototype systemsincluding bundles of technologies have been reported above 50 percent.This roundtable session will describe the current practices, summarizethe results of past and ongoing studies, discuss ways to think about hotwater system efficiency, and point to areas of future study. We will alsorecommend further steps to reduce unnecessary losses from hot waterdistribution systems.

  13. Purge water management system

    Microsoft Academic Search

    J. E. Cardoso-Neto; D. W. Williams

    1995-01-01

    A purge water management system is described for effectively eliminating the production of purge water when obtaining a groundwater sample from a monitoring well. In its preferred embodiment, the purge water management system comprises an expandable container, a transportation system, and a return system. The purge water management system is connected to a wellhead sampling configuration, typically permanently installed at

  14. Purge water management system

    Microsoft Academic Search

    J. E. Cardoso-Neto; D. W. Williams

    1996-01-01

    A purge water management system is described for effectively eliminating the production of purge water when obtaining a groundwater sample from a monitoring well. In its preferred embodiment, the purge water management system comprises an expandable container, a transportation system, and a return system. The purge water management system is connected to a wellhead sampling configuration, typically permanently installed at

  15. Purge water management system

    Microsoft Academic Search

    Joao E. Cardoso-Neto; Daniel W. Williams

    1996-01-01

    A purge water management system for effectively eliminating the production of purge water when obtaining a groundwater sample from a monitoring well. In its preferred embodiment, the purge water management system comprises an expandable container, a transportation system, and a return system. The purge water management system is connected to a wellhead sampling configuration, typically permanently installed at the well

  16. Exhaust gas recirculation system

    SciTech Connect

    Rachedi, S.H.

    1983-08-16

    An EGR assembly is disclosed of a sonic flow EGR valve and a fluid pressure actuated servo operated by air pressure modified by an air bleed device controlled in response to changes in carburetor venturi vacuum levels to provide EGR valve openings in proportion to engine air flow increases.

  17. Exhaust gas recirculation system

    SciTech Connect

    Rachedi, S.H.

    1983-10-18

    There is disclosed an EGR assembly of a sonic flow EGR valve and a fluid pressure actuated servo operated by air pressure modified by an air bleed device controlled in response to changes in carburetor venturi vacuum levels to provide EGR valve openings in proportion to engine air flow increases.

  18. Peach bottom recirculation piping replacement ALARA program

    SciTech Connect

    Englesson, G.A.; Hilsmeier, A.E.; Mann, B.J.

    1986-01-01

    In late 1983, Philadelphia Electric Company (PECo) began detailed planning to replace the recirculation, residual heat removal, and part of the reactor water cleanup piping of the Peach Bottom Unit 2 reactor. Included in this work was an estimate of the collective exposure expected during piping replacement. That initial estimate, 1945 man-rem, is compared with the actual collective dose incurred during the piping replacement program. Also included are the exposures incurred during two additional tasks (safe end replacement and recirculation pump disassembly and decontamination) not considered in the initial estimate.

  19. BWR recirculation pump isolation valve disk stellite repair

    SciTech Connect

    Alexakos, N.P.

    1985-01-01

    A major repair program was developed for the unit 2 recirculation pump isolation valves at the Peach Bottom atomic power station after an initial inspection revealed disk seat cracking. The access for inspection of these valves was made possible due to the recirculation system piping replacement during the sixth refueling outage. This was the first opportunity to disassemble the valves completely for inspection since the construction phase. These valves are the only blocking point between the reactor and the recirculation pumps. Preparation for the disassembly and inspection was planned prior to the recirculation piping replacement. A description of the maintenance procedure, problem areas, and results are presented.

  20. EXHAUST GAS RECIRCULATION

    E-print Network

    Chapman, Clark R.

    to be an effective approach to reduce NOx emissions in order to meet US2007 and US2010 emissions regulations environmental regulations for diesel engine emissions are becoming increas- ingly stringent, and are driving) and oxides of nitrogen (NOx). The use of exhaust gas recirculation (EGR) coolers is considered

  1. Mass transfer efficiency of a vacuum airlift—Application to water recycling in aquaculture systems

    Microsoft Academic Search

    Bertrand Barrut; Jean-Paul Blancheton; Jean-Yves Champagne; Alain Grasmick

    In aquaculture, oxygen transfer and carbon dioxide stripping are the first limiting factors to fish rearing intensification. In this study we measured the O2 and CO2 mass transfer coefficient (KLa) for a vacuum airlift in fresh (<1‰ salinity) and sea water (35‰ salinity) recirculating aquaculture systems (RAS). The airlift was composed of two concentric tubes: an inner riser tube and

  2. DECONTAMINATION STUDIES FOR HAPO WATER-COOLED REACTOR SYSTEMS. Progress Report, September 1, 1960September 1, 1961

    Microsoft Academic Search

    J. A. Ayres; T. F. Demmitt; A. P. Larrick; L. D. Perrigo; R. B. Richmann; R. D. Weed

    1962-01-01

    An intensive decontamination program is being conducted to determine the ; effectiveness or prospective processes for high-temperature, recirculating, ; water-cooled and lowtemperature, single-pass, water-cooled reactor systems. ; Candidate processes are also being evaluated to determine their corrosion ; characteristics. Two distinct types of contamination are encountered in nuclear ; reactors: fission and rupture products from fuel elements and activated corrosion

  3. General noise analysis of recirculating delay line structures

    Microsoft Academic Search

    Eric C. Heyde

    1997-01-01

    Recirculating delay lines have value notably as sensors and optical signal processors. One of their main limitations is that phase noise from the source is converted to amplitude noise at the detector and that intensity noise is also filtered by the system. An expression is derived for the filtering effect that a recirculating delay line topology has on both the

  4. Biodiversity of N-cycle bacteria in nitrogen removing moving bed biofilters for freshwater recirculating aquaculture systems

    Microsoft Academic Search

    Maartje A. H. J. van Kessel; Harry R. Harhangi; Katinka van de Pas-Schoonen; J. L. C. M. van de Vossenberg; Gert Flik; Mike S. M. Jetten; Peter H. M. Klaren

    2010-01-01

    Maintenance of optimal water quality and removal of nitrogen compounds pose challenges to aquaculture worldwide. Presence and activity of different bacteria involved in nitrogen cycling in the biofilm of a moving bed biofilm reactor (MBBR) connected to a Koi carp tank were investigated experimentally. For this MBBR system, a nitrogen removing rate of 3.5g nitrogen per day was found in

  5. Use of recirculating aquaculture systems to increase production and quality of hatchery reared juvenile red drum for marine stock enhancement

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The abundance of economically important marine sportfish has declined in Florida’s waters due to factors such as over-fishing and critical habitat disturbance. Hatchery production and enhancement stocking has traditionally been used in freshwater systems as a means of mitigating for effects such as ...

  6. DESIGN CHARACTERISTICS OF THE USDA/ARS-HBOI SUSTAINABLE TANK AQUACULTURE RECIRCULATING RESEARCH (STARR) FACILITY FOR LOW-SALINITY FINFISH PRODUCTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water treatment components of a recirculating aquaculture system (RAS) consist mainly of: solid removal devices, biofiltration, aeration and degassing units, and water distribution mechanisms. For each component, multiple options are available and the selection is based on system volume and hydrodyn...

  7. The potential leaching and mobilization of trace elements from FGD-gypsum of a coal-fired power plant under water re-circulation conditions.

    PubMed

    Córdoba, Patricia; Castro, Iria; Maroto-Valer, Mercedes; Querol, Xavier

    2015-06-01

    Experimental and geochemical modelling studies were carried out to identify mineral and solid phases containing major, minor, and trace elements and the mechanism of the retention of these elements in Flue Gas Desulphurisation (FGD)-gypsum samples from a coal-fired power plant under filtered water recirculation to the scrubber and forced oxidation conditions. The role of the pH and related environmental factors on the mobility of Li, Ni, Zn, As, Se, Mo, and U from FGD-gypsums for a comprehensive assessment of element leaching behaviour were also carried out. Results show that the extraction rate of the studied elements generally increases with decreasing the pH value of the FGD-gypsum leachates. The increase of the mobility of elements such as U, Se, and As in the FGD-gypsum entails the modification of their aqueous speciation in the leachates; UO2SO4, H2Se, and HAsO2 are the aqueous complexes with the highest activities under acidic conditions. The speciation of Zn, Li, and Ni is not affected in spite of pH changes; these elements occur as free cations and associated to SO4(2) in the FGD-gypsum leachates. The mobility of Cu and Mo decreases by decreasing the pH of the FGD-gypsum leachates, which might be associated to the precipitation of CuSe2 and MoSe2, respectively. Time-of-Flight mass spectrometry of the solid phase combined with geochemical modelling of the aqueous phase has proved useful in understanding the mobility and geochemical behaviour of elements and their partitioning into FGD-gypsum samples. PMID:26040733

  8. Options for transpiration water removal in a crop growth system under zero gravity conditions

    NASA Technical Reports Server (NTRS)

    Blackwell, C. C.; Kliss, M.; Yendler, B.; Borchers, B.; Yendler, Boris S.; Nguyen, Thoi K.; Waleh, Ahmad

    1991-01-01

    The operation of a microgravity crop-growth system is a critical feature of NASA's Closed Ecological Life Support System (CELSS) development program. Transpiration-evolved water must be removed from the air that is recirculated in such a system, perhaps supplying potable water in the process. The present consideration of candidate systems for CELSS water removal gives attention to energy considerations and to a mechanical, inertial-operation water-separation system that was chosen due to the depth of current understanding of its operation.

  9. Effluent Treatment and Residuals Management Using Land Application to Recycle Nutrients from a Large-Scale Recirculating Aquaculture Facility

    Microsoft Academic Search

    Scott Lindell; Roscoe E. Perham

    AquaFuture operates a 1.8 million gallon recirculating aquaculture facility capable of filtering the waste products from over three quarters of a million fish that are fed over one million pounds of feed per year. This paper describes a compact system for effluent treatment and residuals management that has proven effective at maintaining water quality within compliance limitations. Solids are removed

  10. Recirculation-aeration: Bibliography for aquaculture. Bibliographies and literature of agriculture (Final)

    SciTech Connect

    Perschbacher, P.W.; Powell, R.V.; Freeman, D.W.; Lorio, W.J.; Hanfman, D.T.

    1993-08-01

    The bibliography includes literature citations through 1992 related to water recirculation and aeration in aquaculture. The focus is on filtration, aeration, and circulation techniques in various aquaculture situations.

  11. Water Purification Systems

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A water purification/recycling system developed by Photo-Catalytics, Inc. (PCI) for NASA is commercially available. The system cleanses and recycles water, using a "photo-catalysis" process in which light or radiant energy sparks a chemical reaction. Chemically stable semiconductor powders are added to organically polluted water. The powder absorbs ultraviolet light, and pollutants are oxidized and converted to carbon dioxide. Potential markets for the system include research and pharmaceutical manufacturing applications, as well as microchip manufacture and wastewater cleansing.

  12. Reactor water cleanup system

    DOEpatents

    Gluntz, D.M.; Taft, W.E.

    1994-12-20

    A reactor water cleanup system includes a reactor pressure vessel containing a reactor core submerged in reactor water. First and second parallel cleanup trains are provided for extracting portions of the reactor water from the pressure vessel, cleaning the extracted water, and returning the cleaned water to the pressure vessel. Each of the cleanup trains includes a heat exchanger for cooling the reactor water, and a cleaner for cleaning the cooled reactor water. A return line is disposed between the cleaner and the pressure vessel for channeling the cleaned water thereto in a first mode of operation. A portion of the cooled water is bypassed around the cleaner during a second mode of operation and returned through the pressure vessel for shutdown cooling. 1 figure.

  13. Mechanisms of recirculating liquid flow on distillation sieve plates

    SciTech Connect

    Biddulph, M.W. (Univ. of Nottingham (United Kingdom). Dept. of Chemical Engineering); Burton, A.C. (BOC Group, Murray Hill, NJ (United States))

    1994-11-01

    This paper describes an experimental investigation into the phenomenon of flow recirculation on distillation sieve trays. A novel dye injection technique has been applied to a 1.81 m air-water simulation column and has yielded new information concerning the nature of the boundary layer of gas-liquid biphase as it detaches from the column wall. The study has shown that recirculation is strongly influenced by inlet conditions. A critical factor is the underflow clearance between the inlet downcomer apron and the tray floor. As this clearance is increased, the size of the recirculating zones passes through a minimum, indicating the existence of two different mechanisms responsible for the nonuniform flow patterns. A significant implication of this work is that tray designers may minimize the impact of recirculating on mass transfer efficiency by appropriate choice of underflow clearance.

  14. Evaluating Domestic Hot Water Distribution System Options With Validated Analysis Models

    SciTech Connect

    Weitzel, E.; Hoeschele, M.

    2014-09-01

    A developing body of work is forming that collects data on domestic hot water consumption, water use behaviors, and energy efficiency of various distribution systems. A full distribution system developed in TRNSYS has been validated using field monitoring data and then exercised in a number of climates to understand climate impact on performance. This study builds upon previous analysis modelling work to evaluate differing distribution systems and the sensitivities of water heating energy and water use efficiency to variations of climate, load, distribution type, insulation and compact plumbing practices. Overall 124 different TRNSYS models were simulated. Of the configurations evaluated, distribution losses account for 13-29% of the total water heating energy use and water use efficiency ranges from 11-22%. The base case, an uninsulated trunk and branch system sees the most improvement in energy consumption by insulating and locating the water heater central to all fixtures. Demand recirculation systems are not projected to provide significant energy savings and in some cases increase energy consumption. Water use is most efficient with demand recirculation systems, followed by the insulated trunk and branch system with a central water heater. Compact plumbing practices and insulation have the most impact on energy consumption (2-6% for insulation and 3-4% per 10 gallons of enclosed volume reduced). The results of this work are useful in informing future development of water heating best practices guides as well as more accurate (and simulation time efficient) distribution models for annual whole house simulation programs.

  15. Purge water management system

    DOEpatents

    Cardoso-Neto, J.E.; Williams, D.W.

    1995-01-01

    A purge water management system is described for effectively eliminating the production of purge water when obtaining a groundwater sample from a monitoring well. In its preferred embodiment, the purge water management system comprises an expandable container, a transportation system, and a return system. The purge water management system is connected to a wellhead sampling configuration, typically permanently installed at the well site. A pump, positioned with the monitoring well, pumps groundwater through the transportation system into the expandable container, which expands in direct proportion with volume of groundwater introduced, usually three or four well volumes, yet prevents the groundwater from coming into contact with the oxygen in the air. After this quantity of groundwater has been removed from the well, a sample is taken from a sampling port, after which the groundwater in the expandable container can be returned to the monitoring well through the return system. The purge water management system prevents the purge water from coming in contact with the outside environment, especially oxygen, which might cause the constituents of the groundwater to oxidize. Therefore, by introducing the purge water back into the monitoring well, the necessity of dealing with the purge water as a hazardous waste under the Resource Conservation and Recovery Act is eliminated.

  16. Purge water management system

    DOEpatents

    Cardoso-Neto, Joao E. (North Augusta, SC); Williams, Daniel W. (Aiken, SC)

    1996-01-01

    A purge water management system for effectively eliminating the production of purge water when obtaining a groundwater sample from a monitoring well. In its preferred embodiment, the purge water management system comprises an expandable container, a transportation system, and a return system. The purge water management system is connected to a wellhead sampling configuration, typically permanently installed at the well site. A pump, positioned with the monitoring well, pumps groundwater through the transportation system into the expandable container, which expands in direct proportion with volume of groundwater introduced, usually three or four well volumes, yet prevents the groundwater from coming into contact with the oxygen in the air. After this quantity of groundwater has been removed from the well, a sample is taken from a sampling port, after which the groundwater in the expandable container can be returned to the monitoring well through the return system. The purge water management system prevents the purge water from coming in contact with the outside environment, especially oxygen, which might cause the constituents of the groundwater to oxidize. Therefore, by introducing the purge water back into the monitoring well, the necessity of dealing with the purge water as a hazardous waste under the Resource Conservation and Recovery Act is eliminated.

  17. Cooling water distribution system

    DOEpatents

    Orr, Richard (Pittsburgh, PA)

    1994-01-01

    A passive containment cooling system for a nuclear reactor containment vessel. Disclosed is a cooling water distribution system for introducing cooling water by gravity uniformly over the outer surface of a steel containment vessel using an interconnected series of radial guide elements, a plurality of circumferential collector elements and collector boxes to collect and feed the cooling water into distribution channels extending along the curved surface of the steel containment vessel. The cooling water is uniformly distributed over the curved surface by a plurality of weirs in the distribution channels.

  18. Heavy metal and waste metabolite accumulation and their potential effect on rainbow trout performance in a replicated water reuse system operated at low or high system flushing rates

    Microsoft Academic Search

    John Davidson; Christopher Good; Carla Welsh; Brian Brazil; Steven Summerfelt

    2009-01-01

    A six-month trial was conducted to compare the effects of high and low make-up water flushing rates on rainbow trout performance and water quality in replicated water reuse aquaculture systems (WRAS). Six identical 9.5m3 WRAS, containing a single 5.3m3 tank and operated at a total recirculating flow of 380L\\/min were stocked with 1000 rainbow trout each (133±1g). Three WRAS were

  19. Cooling Water System Optimization 

    E-print Network

    Aegerter, R.

    2005-01-01

    During summer months, many manufacturing plants have to cut back in rates because the cooling water system is not providing sufficient cooling to support higher production rates. There are many low/no-cost techniques available to improve tower...

  20. Ground Water Cooling System 

    E-print Network

    Greaves, K.; Chave, G. H.

    1984-01-01

    GROUND WATER COOLING SYSTEM Keith Greaves/George H. Chave Westinghouse Canada Inc. Hamilton, Ontario ABSTRACT Based on a thorough study of products and anticipated growth, the Turbine and Generator Division of Westinghouse Canada Inc...

  1. Monitoring of Leachate Recirculation in a Bioreactor Using Electrical Resistivity

    NASA Astrophysics Data System (ADS)

    Grellier, S.; Bureau, N.; Robain, H.; Tabbagh, A.; Camerlynck, C.; Guerin, R.

    2004-05-01

    The bioreactor is a concept of waste landfill management consisting in speeding up the biodegradation by optimizing the moisture content through leachate recirculation. Electrical resistivity tomography (ERT) is carried out with fast resistivity-meter (Syscal Pro, IRIS Instruments, developed in the framework of the research project CERBERE 01V0665-69, funded by the French Research Ministry) to monitor leachate recirculation. During a recirculation period waste moisture increases, so that electrical resistivity may decrease, but at the same time temperature and mineralization of both waste and leachate become intermixed. If waste temperature is much higher than leachate temperature electrical resistivity will not decrease as much as if the temperature difference was smaller. If leachate mineralization (i.e. leachate conductivity) is higher than that of wet waste in the landfill, electrical resistivity will tend to decrease. Otherwise for example after an addition of rain water into the leachate storage or in case of very wet waste, the resistivities of each medium (leachate and wet waste) can be almost the same, so that leachate mineralization will not have a great influence on waste resistivity. Resistivity measurements were performed during 85 minutes injection trials (with a discharge of 20 m3 h-1) where leachate was injected through a vertical borehole perforated between 1.85 and 4.15 m. Three first measurements are made during the injection (3, 30 and 60 minutes from the beginning of the injection) and the two other after the injection period (8 and 72 minutes after the end of the injection). Apparent and interpreted resistivity variations that occurred during injection trials, expressed as the relative differences (in %) between apparent, respectively interpreted, resistivity during injection and apparent, respectively interpreted, resistivity before injection (reference measurement) show the formation of a plume (a negative anomaly: resistivity decreases with increasing moisture content). The positive anomaly could be explained by an increasing of biogas proportion in waste porosity. For this experiment, leachate temperature is relatively cold (between 5 and 10° C, as the injection trials take place at the end of October), leachate conductivity is about 9200 ? S cm-1 (i.e. a resistivity of 1.1 ? m) and waste resistivity in the borehole region is about 80 ? m. This is a situation where the temperature difference between waste and leachate is large and the resistivity difference between waste and leachate is high. The resistivity variation is essentially due to waste moisture increase. ERT method allows leachate diffusion to be seen through the waste mass and the influence zone of the leachate recirculation system to be determined.

  2. Effects of spectral composition, photoperiod and light intensity on the gonadal development of Atlantic salmon Salmo salar in recirculating aquaculture systems (RAS)

    NASA Astrophysics Data System (ADS)

    Qiu, Denggao; Xu, Shihong; Song, Changbin; Chi, Liang; Li, Xian; Sun, Guoxiang; Liu, Baoliang; Liu, Ying

    2015-01-01

    Artificial lighting regimes have been successfully used to inhibit sexual maturity of Atlantic salmon in confinement. However, when these operations are applied in commercial recirculating aquaculture systems (RAS) using standard lighting technology, sexual maturation is not suppressed. In this study, an L9 (33) orthogonal design was used to determine the effects of three factors (spectral composition, photoperiod, and light intensity) on the gonadal development of Atlantic salmon in RAS. We demonstrated that the photoperiod at the tested levels had a much greater effect on the gonadosomatic index and female Fulton condition factor than spectral composition and light intensity. The photoperiod had a significant effect on the secretion of sex steroids and melatonin ( P<0.05), and a short photoperiod delayed sex steroid and melatonin level increases. The three test factors had no significant effects on the survival rate, specific growth rate, relative weight gain, and male Fulton condition factor ( P>0.05). The optimum lighting levels in female and male Atlantic salmon were LD 8:16, 455 nm (or 625 nm), 8.60 W/m2; and LD 8:16, 8.60 W/m2, 455 nm respectively. These conditions not only delayed gonadal development, but also had no negative effects on Atlantic salmon growth in RAS. These results demonstrate that a combination of spectral composition, photoperiod and light intensity is effective at delaying the gonadal development of both male and female salmon in RAS.

  3. Hydrogen sulfide oxidation by a microbial consortium in a recirculation reactor system: sulfur formation under oxygen limitation and removal of phenols.

    PubMed

    Alcantara, Sergio; Velasco, Antonio; Muñoz, Ana; Cid, Juan; Revah, Sergio; Razo-Flores, Elías

    2004-02-01

    Wastewater from petroleum refining may contain a number of undesirable contaminants including sulfides, phenolic compounds, and ammonia. The concentrations of these compounds must be reduced to acceptable levels before discharge. Sulfur formation and the effect of selected phenolic compounds on the sulfide oxidation were studied in autotrophic aerobic cultures. A recirculation reactor system was implemented to improve the elemental sulfur recovery. The relation between oxygen and sulfide was determined calculating the O2/S2- loading rates (Q(O2)/Q(S)2- = Rmt), which adequately defined the operation conditions to control the sulfide oxidation. Sulfur-producing steady states were achieved at Rmt ranging from 0.5 to 1.5. The maximum sulfur formation occurred at Rmt of 0.5 where 85% of the total sulfur added to the reactor as sulfide was transformed to elemental sulfur and 90% of it was recovered from the bottom of the reactor. Sulfide was completely oxidized to sulfate (Rmt of 2) in a stirred tank reactor, even when a mixture of phenolic compounds was present in the medium. Microcosm experiments showed that carbon dioxide production increased in the presence of the phenols, suggesting that these compounds were oxidized and that they may have been used as carbon and energy source by heterotrophic microorganisms present in the consortium. PMID:14968883

  4. Application of chemical coagulation aids for the removal of suspended solids (TSS) and phosphorus from the microscreen effluent discharge of an intensive recirculating aquaculture system

    USGS Publications Warehouse

    Ebeling, J.M.; Ogden, S.R.; Sibrell, P.L.; Rishel, K.L.

    2004-01-01

    An evaluation of two commonly used coagulation-flocculation aids (alum and ferric chloride) was conducted to determine optimum conditions for treating the backwash effluent from microscreen filters in an intensive recirculating aquaculture system. Tests were carried out to evaluate the dosages and conditions (mixing and flocculation stirring speeds, durations, and settling times) required to achieve optimum waste capture. The orthophosphate removal efficiency for alum and ferric chloride were greater than 90% at a dosage of 60 mg/L. Optimum turbidity removal was achieved with a 60-mg/L dosage for both alum and ferric chloride. Both alum and ferric chloride demonstrated excellent removal of suspended solids from initial total suspended solid values of approximately 320 mg/L to approximately 10 mg/L at a dosage of 60 mg/L. Flocculation and mixing speed and duration played only a minor role in the removal efficiencies for both orthophosphates and suspended solids. Both coagulation-flocculation aids also exhibited excellent settling characteristics, with the majority of the floc quickly settling out in the first 5 min.

  5. Effect of Dietary Supplementation of Brewer's Yeast and GroBiotic®-A on Growth, Immune Responses, and Low-Salinity Tolerance of Pacific White Shrimp Litopenaeus vannamei Cultured in Recirculating Systems

    Microsoft Academic Search

    Peng Li; Xiaoxue Wang; Shivananda Murthy; Delbert M. Gatlin III; Frank L. Castille; Addison L. Lawrence

    2009-01-01

    Two separate trials were conducted in clean recirculating systems at salinities of 32.9 (optimal) and 2 ppt (low-salinity challenge) to evaluate brewer's yeast and GroBiotic®-A, a commercial prebiotic, as dietary supplements for growth and health management of Pacific white shrimp Litopenaeus vannamei. The growth-promoting influences of brewer's yeast or GroBiotic®-A previously observed with fish were not demonstrated in these trials

  6. Spacesuit Water Membrane Evaporator; An Enhanced Evaporative Cooling Systems for the Advanced Extravehicular Mobility Unit Portable Life Support System

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Makinen, Janice V.; Miller, Sean.; Campbell, Colin; Lynch, Bill; Vogel, Matt; Craft, Jesse; Petty, Brian

    2014-01-01

    Spacesuit Water Membrane Evaporator - Baseline heat rejection technology for the Portable Life Support System of the Advanced EMU center dot Replaces sublimator in the current EMU center dot Contamination insensitive center dot Can work with Lithium Chloride Absorber Radiator in Spacesuit Evaporator Absorber Radiator (SEAR) to reject heat and reuse evaporated water The Spacesuit Water Membrane Evaporator (SWME) is being developed to replace the sublimator for future generation spacesuits. Water in LCVG absorbs body heat while circulating center dot Warm water pumped through SWME center dot SWME evaporates water vapor, while maintaining liquid water - Cools water center dot Cooled water is then recirculated through LCVG. center dot LCVG water lost due to evaporation (cooling) is replaced from feedwater The Independent TCV Manifold reduces design complexity and manufacturing difficulty of the SWME End Cap. center dot The offset motor for the new BPV reduces the volume profile of the SWME by laying the motor flat on the End Cap alongside the TCV.

  7. Water-quality modeling of Klamath Straits Drain recirculation, a Klamath River wetland, and 2011 conditions for the Link River to Keno Dam reach of the Klamath River, Oregon

    USGS Publications Warehouse

    Sullivan, Annett B.; Sogutlugil, I. Ertugrul; Deas, Michael L.; Rounds, Stewart A.

    2014-01-01

    The upper Klamath River and adjacent Lost River are interconnected basins in south-central Oregon and northern California. Both basins have impaired water quality with Total Maximum Daily Loads (TMDLs) in progress or approved. In cooperation with the Bureau of Reclamation, the U.S. Geological Survey (USGS) and Watercourse Engineering, Inc., have conducted modeling and research to inform management of these basins for multiple purposes, including agriculture, endangered species protection, wildlife refuges, and adjacent and downstream water users. A water-quality and hydrodynamic model (CE-QUAL-W2) of the Link River to Keno Dam reach of the Klamath River for 2006–09 is one of the tools used in this work. The model can simulate stage, flow, water velocity, ice cover, water temperature, specific conductance, suspended sediment, nutrients, organic matter in bed sediment and the water column, three algal groups, three macrophyte groups, dissolved oxygen, and pH. This report documents two model scenarios and a test of the existing model applied to year 2011, which had exceptional water quality. The first scenario examined the water-quality effects of recirculating Klamath Straits Drain flows into the Ady Canal, to conserve water and to decrease flows from the Klamath Straits Drain to the Klamath River. The second scenario explicitly incorporated a 2.73×106 m2 (675 acre) off-channel connected wetland into the CE-QUAL-W2 framework, with the wetland operating from May 1 through October 31. The wetland represented a managed treatment feature to decrease organic matter loads and process nutrients. Finally, the summer of 2011 showed substantially higher dissolved-oxygen concentrations in the Link-Keno reach than in other recent years, so the Link-Keno model (originally developed for 2006–09) was run with 2011 data as a test of model parameters and rates and to develop insights regarding the reasons for the improved water-quality conditions.

  8. Recycling crop residues for use in recirculating hydroponic crop production

    NASA Technical Reports Server (NTRS)

    Mackowiak, C. L.; Garland, J. L.; Sager, J. C.

    1996-01-01

    As part of bioregenerative life support feasibility testing by NASA, crop residues are being used to resupply elemental nutrients to recirculating hydroponic crop production systems. Methods for recovering nutrients from crop residues have evolved from water soaking (leaching) to rapid aerobic bioreactor processing. Leaching residues recovered the majority of elements but it also recovered significant amounts of soluble organics. The high organic content of leachates was detrimental to plant growth. Aerobic bioreactor processing reduced the organic content ten-fold, which reduced or eliminated phytotoxic effects. Wheat and potato production studies were successful using effluents from reactors having with 8- to 1-day retention times. Aerobic bioreactor effluents supplied at least half of the crops elemental mass needs in these studies. Descriptions of leachate and effluent mineral content, biomass productivity, microbial activity, and nutrient budgets for potato and wheat are presented.

  9. Multiple trophic levels fueled by recirculation in the Columbia River plume

    NASA Astrophysics Data System (ADS)

    Kudela, Raphael M.; Horner-Devine, Alexander R.; Banas, Neil S.; Hickey, Barbara M.; Peterson, Tawnya D.; McCabe, Ryan M.; Lessard, Evelyn J.; Frame, Elizabeth; Bruland, Kenneth W.; Jay, David A.; Peterson, Jay O.; Peterson, William T.; Kosro, P. Michael; Palacios, Sherry L.; Lohan, Maeve C.; Dever, Edward P.

    2010-09-01

    Large rivers represent gateways for the transport of terrigenous and anthropogenic material to the coastal ocean. Here we document a ˜700 km2 recirculation or bulge associated with the Columbia River plume that retains recently discharged river water sufficiently to create a regional bioreactor. Fueled by a fluvial nitrate source, this feature stimulated growth across three trophic levels and may buffer this gateway system during periods of increased warming and stratification that lead to decreased ocean productivity, potentially enhancing production at multiple trophic levels and enriching surface waters far from the river mouth.

  10. Water system virus detection

    NASA Technical Reports Server (NTRS)

    Fraser, A. S.; Wells, A. F.; Tenoso, H. J.

    1975-01-01

    A monitoring system developed to test the capability of a water recovery system to reject the passage of viruses into the recovered water is described. A nonpathogenic marker virus, bacteriophage F2, is fed into the process stream before the recovery unit and the reclaimed water is assayed for its presence. Detection of the marker virus consists of two major components, concentration and isolation of the marker virus, and detection of the marker virus. The concentration system involves adsorption of virus to cellulose acetate filters in the presence of trivalent cations and low pH with subsequent desorption of the virus using volumes of high pH buffer. The detection of the virus is performed by a passive immune agglutination test utilizing specially prepared polystyrene particles. An engineering preliminary design was performed as a parallel effort to the laboratory development of the marker virus test system. Engineering schematics and drawings of a fully functional laboratory prototype capable of zero-G operation are presented. The instrument consists of reagent pump/metering system, reagent storage containers, a filter concentrator, an incubation/detector system, and an electronic readout and control system.

  11. Water and River Systems

    NSDL National Science Digital Library

    Timothy Heaton

    This site contains 25 questions on the topic of water and river systems, which covers the hydrologic cycle and drainage patterns. This is part of the Principles of Earth Science course at the University of South Dakota. Users submit their answers and are provided immediate feedback.

  12. Water heating system

    Microsoft Academic Search

    Yoshino

    1984-01-01

    A water heating system comprising an outdoor heat exchanger including a heat collection chamber, solar collector panels, collector fins, an evaporator for passing refrigerant therethrough to perform the heat exchange between the refrigerant and the heat transferred from the panels and fins to evaporate the refrigerant. The panels, fins and evaporator are incorporated integrally in the heat collection chamber. A

  13. Growth performance, fillet quality, and reproductive maturity of rainbow trout (Oncorhynchus mykiss) cultured to 5 kilograms within freshwater recirculating systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rainbow trout are commonly cultured within aquaculture systems to one pound or less and marketed as pan-sized fillets. Production of larger rainbow trout provides a distinguishable product. Research that describes the growth performance and fillet quality of large rainbow trout is limited, particula...

  14. Internal reforming fuel cell system requiring no recirculated cooling and providing a high fuel process gas utilization

    Microsoft Academic Search

    Farooque

    1990-01-01

    This patent describes a system. It comprises: a high temperature fuel cell including: an anode passage comprising an anode electrode, the anode passage being adapted to receive fuel process gas; a cathode passage comprising a cathode electrode. The cathode passage being adapted to receive an oxidant process gas; and electrolyte in communications with the anode and cathode electrodes; catalyst means

  15. Identification of Bacteria Potentially Responsible for Oxic and Anoxic Sulfide Oxidation in Biofilters of a Recirculating Mariculture System

    Microsoft Academic Search

    Eddie Cytryn; Jaap van Rijn; Andreas Schramm; Armin Gieseke; Dirk de Beer; Dror Minz

    2005-01-01

    Bacteria presumably involved in oxygen- or nitrate-dependent sulfide oxidation in the biofilters of a recir- culating marine aquaculture system were identified using a new application of reverse transcription-PCR denaturing gradient gel electrophoresis (DGGE) analysis termed differential-transcription (DT)-DGGE. Bio- filter samples were incubated in various concentrations of sulfide or thiosulfate (0 to 5 mM) with either oxygen or nitrate as the

  16. Tide-induced recirculation across the aquifer-ocean interface

    Microsoft Academic Search

    C. Robinson; L. Li; H. Prommer

    2007-01-01

    A parametric analysis is conducted to examine the influence of tides, inland hydraulic conditions, and aquifer properties on the rate of tide-induced seawater recirculation through the nearshore aquifer. Understanding such influence is crucial for accurate prediction of subsurface chemical fluxes to coastal waters via groundwater discharge. The analysis is based on numerical simulations of density-dependent groundwater flow in a coastal

  17. Blood cytokine, chemokine and gene expression in cholestasis patients with intractable pruritus treated with a molecular adsorbent recirculating system: A case series

    PubMed Central

    Lisboa, Luiz F; Asthana, Sonal; Kremer, Andreas E; Swain, Mark; Bagshaw, Sean M; Gibney, Noel; Karvellas, Constantine J

    2012-01-01

    BACKGROUND: The molecular adsorbent recirculating system (MARS) is an albumin-dialysis modality that has been investigated predominantly in patients with acute and acute-on-chronic liver failure. OBJECTIVES: To report the clinical efficacy and safety of MARS therapy for intractable pruritus in cholestasis patients with stable chronic liver disease, characterizing the impact of MARS on cytokine levels and on the transcriptome in the blood compartment. METHODS: MARS therapy was performed on three patients with cholestatic liver disease using 8 h runs for two consecutive days. The expression levels of 65 cytokines/chemokines and 24,000 genes were profiled by Luminex (Luminex Corporation, USA) and microarray, respectively. RESULTS: A quality-of-life assessment demonstrated a marked improvement during therapy, which was sustained in two of three patients. No bleeding or infectious complications were observed. Bile acid levels were markedly reduced following MARS (mean [± SD] pretreatment 478.9±112.2 ?mol/L versus post-treatment 89.7±68.8 ?mol/L). Concordant decreases in cytokine/chemokine levels were noted for interleukin (IL)-1beta, IL-2, IL-6, IL-8, IL-12 (p40), RANTES, tranforming growth factor-alpha, tumour necrosis factor-alpha and thrombopoietin following MARS. On microarray profiling, biologically relevant concordant changes among all patients were evident for 20 different genes (10 upregulated and 10 downregulated). The upregulation of several potentially immune suppressive/regulatory genes (eg, early growth response 3 [EGR-3], ephrin-A2 [EFNA2] and serum amyloid A1 [SAA1]), concurrent with downregulation of genes involved in innate immunity (eg, toll-like receptor 4 interactor with leucine-rich repeats [TRIL]) and inflammation (eg, ephrin receptor B1 [EPHB1]), was observed. CONCLUSIONS: This investigative approach offers new insights into intractable pruritus and suggests future therapeutic targets. The clinical benefit of MARS in cholestasis patients with intractable pruritus may not exclusively result from filtration of pruritogens, but also from systemic changes in cytokine/chemokine levels and changes in gene expression of blood cells. PMID:23166903

  18. WUIS: water use information system

    Microsoft Academic Search

    J. C. Sonnichsen; J. F. Fletcher

    1980-01-01

    The Water Use Information System (WUIS) contains data on water use requirements for thermal electric power plants and on water resources. The system provides a means whereby data can be retrieved in an expedient and orderly manner for purposes of performing environmental assessments and reviewing the potential impacts associated with proposed energy resources development on water resources. Retrieval and use

  19. [Effects of leachate recirculation volume on its characteristic and landfill stabilization rate].

    PubMed

    Deng, Zhou; Jiang, Jian-Guo; Yang, Guo-Dong; Huang, Zhong-Lin; Feng, Xiang-Ming; Zhou, Sheng-Yong

    2006-01-01

    Impacts of recirculation volume on leachate characteristic and landfill stabilization rate were studied. Four simulated bioreactor landfill columns were operated weekly with different recirculation ratios, respectively 5.3%, 2.7%, 0.67% leachate and 0.33% water, in this comparative research. The results indicate that simulated reactor with 5.3% recirculation ratio has the most rapidly stabilization rate and release the most organic pollutant. The shortest methane generation delay was also observed in this column. While simulated reactor with 2.7% recirculation ratio formed the best microbe environment and kept the highest reactor temperature 35 degrees C. It also had the best impactive load capacity and treating efficiency to leachate, and removal of COD was 77% and BOD5 was 88% respectively. In actual projects, appropriate leachate recirculation volume should be chosen according to design purpose of landfill sites. PMID:16599146

  20. Optimization of Chilled Water Systems

    E-print Network

    Gidwani, B. N.

    1984-01-01

    Chilled water systems are one of the major energy consumers in industrial, commercial, and institutional complexes. The centralization of chilled water systems has considerable advantages, namely: simplified controls, the installed capacity...

  1. Optimization of Chilled Water Systems 

    E-print Network

    Gidwani, B. N.

    1984-01-01

    Chilled water systems are one of the major energy consumers in industrial, commercial, and institutional complexes. The centralization of chilled water systems has considerable advantages, namely: simplified controls, the installed capacity...

  2. Investigation of sludge re-circulating clarifiers design and optimization through numerical simulation.

    PubMed

    Davari, S; Lichayee, M J

    2003-01-01

    In steam thermal power plants (TPP) with open re-circulating wet cooling towers, elimination of water hardness and suspended solids (SS) is performed in clarifiers. Most of these clarifiers are of high efficiency sludge re-circulating type (SRC) with capacity between 500-1,500 m3/hr. Improper design and/or mal-operation of clarifiers in TPPs results in working conditions below design capacity or production of soft water with improper quality (hardness and S.S.). This causes accumulation of deposits in heat exchangers, condenser tubes, cooling and service water pipes and boiler tubes as well as increasing the ionic load of water at the demineralizing system inlet. It also increases the amount of chemical consumptions and produces more liquid and solid waste. In this regard, a software program for optimal design and simulation of SRCs has been developed. Then design parameters of existing SRCs in four TPPs in Iran were used as inputs to developed software program and resulting technical specifications were compared with existing ones. In some cases improper design was the main cause of poor outlet water quality. In order to achieve proper efficiency, further investigations were made to obtain control parameters as well as design parameters for both mal-designed and/or mal-operated SRCs. PMID:14753549

  3. Impact of various leachate recirculation regimes on municipal solid waste degradation

    Microsoft Academic Search

    Irem Šan; Turgut T. Onay

    2001-01-01

    Landfilled municipal solid waste can be treated by introducing leachate into the waste matrix. Increasing attention is being given to landfill leachate recirculation as a means for in situ leachate treatment and landfill stabilization. Landfills with leachate recirculation may be operated as municipal solid waste bioreactor treatment system rather than as a conventional waste dumping sites. In order to study

  4. Digital feedwater and recirculation flow control for GPUN Oyster Creek

    Microsoft Academic Search

    D. Burjorjee; B. Gan

    1992-01-01

    This paper describes the digital system for feedwater and recirculation control that GPU Nuclear will be installing at Oyster Creek during its next outage - expected circa December 1992. The replacement was motivated by considerations of reliability and obsolescence - the analog equipment was aging and reaching the end of its useful life. The new system uses Atomic Energy of

  5. CLOSED-CYCLE WATER-BOILER REACTOR

    Microsoft Academic Search

    1962-01-01

    The design and characteristics of a liquid homogeneous reactor ; providing ultimate protection of the surrounding area against radioactive ; contamination are described. The reactor system is comprised of a water boiler ; reactor having a water solution of enriched uranyl nitrate for a core, hydrogen-; oxygen recombiner system, nitrogen-oxygen recombiner system, sealed closed cycle ; gas recirculating system operating

  6. Cooling Water System Optimization

    E-print Network

    Aegerter, R.

    2005-01-01

    distribution header on the top deck. Water flows from the distribution header through distribution valves to splash boxes that distribute the water to their respective hot water basins. Water then flows through the distribution nozzles and strikes a... splash plate located below each distribution nozzle. The splash plates act like spray nozzles to break up the water into droplets and to evenly distribute the water across the fill. As water falls through the fill, it contacts the air that is being...

  7. Vapor-liquid equilibria of the water + 1,3-propanediol and water + 1,3-propanediol + lithium bromide systems

    SciTech Connect

    Mun, S.Y.; Lee, H.

    1999-12-01

    Vapor-liquid equilibrium data of the water + 1,3-propanediol and water + 1,3-propanediol + lithium bromide systems were measured at 60, 160, 300, and 760 mmHg at temperatures ranging from 315 to 488 K. The apparatus used in this work is a modified still especially designed for the measurement of low-pressure VLE, in which both liquid and vapor are continuously recirculated. For the analysis of salt-containing solutions, a method incorporating refractometry and gravimetry was used. From the experimental measurements, the effect of lithium bromide on the VLE behavior of water + 1,3-propanediol was investigated. The experimental data of the salt-free system were successfully correlated using the Wilson, NRTL, and UNIQUAC models. In addition, the extended UNIQUAC model of Sander et al. was applied to the VLE calculation of salt-containing mixtures.

  8. Integrated Planning for Water and Energy Systems

    E-print Network

    Keller, Arturo A.

    of water in a specific location. #12;Water Extraction & Conveyance Water Treatment End-Use Agricultural Residential Commercial Industrial Water Distribution Wastewater Treatment Wastewater Collection Wastewater Discharge Recycled Water Treatment Recycled Water Distribution Source Source Energy Inputs to Water Systems

  9. Nitrification in Drinking Water Systems

    Microsoft Academic Search

    Yan Zhang; Nancy Love; Marc Edwards

    2009-01-01

    Nitrification is increasingly a concern in United States potable water distribution systems. This paper reviews research on nitrification as it relates to the ammonia levels and unique environments present in potable water distribution systems. Factors affecting nitrification occurrence, nitrification impacts on water quality and corrosion, and nitrification monitoring and control methods are emphasized. The potential role of nitrogen cycling via

  10. 10 Commercially Feasible Urban Recirculating Aquaculture: Addressing the Marine Sector

    Microsoft Academic Search

    Yonathan Zohar; Yossi Tal; Harold Schreier; Colin Steven; John Stubblefield

    With the global collapse of marine fisheries and the environmental issues associated with net-pen aquaculture practices, there is a pressing need to develop fully contained and environmentally sus- tainable approaches to producing seafood. Recirculating aquaculture systems (RAS), which provide this approach, have been widely used over the last two decades to farm freshwater species. However, the cost associated with the

  11. Exhaust gas recirculation for three-valve engine

    Microsoft Academic Search

    S. Yagi; U. Asaka

    1973-01-01

    An exhaust gas recirculation system is described for an internal combustion spark ignition piston engine having a main combustion chamber and an auxiliary combustion chamber connected by a restricted torch nozzle. A lean mixture is supplied to the main combustion chamber, and a rich mixture is supplied to the auxiliary combustion chamber. A conduit conducts a portion of the exhaust

  12. Automated Water-Purification System

    NASA Technical Reports Server (NTRS)

    Ahlstrom, Harlow G.; Hames, Peter S.; Menninger, Fredrick J.

    1988-01-01

    Reverse-osmosis system operates and maintains itself with minimal human attention, using programmable controller. In purifier, membranes surround hollow cores through which clean product water flows out of reverse-osmosis unit. No chemical reactions or phase changes involved. Reject water, in which dissolved solids concentrated, emerges from outer membrane material on same side water entered. Flow controls maintain ratio of 50 percent product water and 50 percent reject water. Membranes expected to last from 3 to 15 years.

  13. Field evaluation of a horizontal well recirculation system for groundwater treatment: Field demonstration at X-701B Portsmouth Gaseous Diffusion Plant, Piketon, Ohio

    SciTech Connect

    Korte, N.; Muck, M.; Kearl, P.; Siegrist, R.; Schlosser, R.; Zutman, J. [Oak Ridge National Lab., TN (United States)] [Oak Ridge National Lab., TN (United States); Houk, T. [Lockheed Martin Energy Systems, Piketon, OH (United States). Portsmouth Gaseous Diffusion Plant] [Lockheed Martin Energy Systems, Piketon, OH (United States). Portsmouth Gaseous Diffusion Plant

    1998-08-01

    This report describes the field-scale demonstration performed as part of the project, In Situ Treatment of Mixed Contaminants in Groundwater. This project was a 3{1/2} year effort comprised of laboratory work performed at Oak Ridge National Laboratory and fieldwork performed at the US Department of Energy (DOE) Portsmouth Gaseous Diffusion Plant (PORTS). The overall goal of the project was to evaluate in situ treatment of groundwater using horizontal recirculation coupled with treatment modules. Specifically, horizontal recirculation was tested because of its application to thin, interbedded aquifer zones. Mixed contaminants were targeted because of their prominence at DOE sites and because they cannot be treated with conventional methods. The project involved several research elements, including treatment process evaluation, hydrodynamic flow and transport modeling, pilot testing at an uncontaminated site, and full-scale testing at a contaminated site. This report presents the results of the work at the contaminated site, X-701B at PORTS. Groundwater contamination at X-701B consists of trichloroethene (TCE) (concentrations up to 1800 mg/L) and technetium-998 (Tc{sup 99}) (activities up to 926 pCi/L).

  14. Evaluation of three types of structured floating plastic media in moving bed biofilters for total ammonia nitrogen removal in a low salinity hatchery recirculating aquaculture system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three different commercially available structural plastic media were evaluated in triplicate in moving bed toriod filters under low salinity (11-12 ppt) warm water culture conditions and two different feed loading rates. The culture system consisted of nine separate modules that include a double dra...

  15. Recirculation in multiple wave conversions

    SciTech Connect

    Kaufman, A. N.; Brizard, A.J.; Kaufman, A.N.; Tracy, E.R.

    2008-07-30

    A one-dimensional multiple wave-conversion model is constructed that allows energy recirculation in ray phase space. Using a modular eikonal approach, the connection coefficients for this model are calculated by ray phase-space methods. Analytical results (confirmed numerically) show that all connection coefficients exhibit interference effects that depend on an interference phase, calculated from the coupling constants and the area enclosed by the intersecting rays. This conceptual model, which focuses on the topology of intersecting rays in phase space, is used to investigate how mode conversion between primary and secondary waves is modified by the presence of a tertiary wave.

  16. Water-based intumescent paint

    NASA Technical Reports Server (NTRS)

    Sauers, D. G.; Nannelli, P.

    1979-01-01

    Article discusses fire-resistant water-based paints made by adding intumescing agents to fluorocarbon coatings. Since these paints are water-based, they do not pollute atmosphere as they dry and can be used in closed-loop air-recirculation system in spacecraft and submarines.

  17. 21 CFR 880.5045 - Medical recirculating air cleaner.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Medical recirculating air cleaner. 880.5045 Section 880.5045 ...880.5045 Medical recirculating air cleaner. (a) Identification. A medical recirculating air cleaner is a device used to remove...

  18. Modelling turbulent recirculating flows in complex geometries

    Microsoft Academic Search

    G. D. Tong

    1984-01-01

    The essential features of modeling turbulent flows containing zones of recirculation are discussed. First, the requirement to adequately represent momentum transfer through a shear layer from a main-stream inducing flow to a recirculating (closed streamline) zone. The k-epsilon model is introduced as a minimum global length scale model for this complex flow type in which there is flow separation, a

  19. Semi-continuous anaerobic co-digestion of cow manure and steam-exploded Salix with recirculation of liquid digestate.

    PubMed

    Estevez, Maria M; Sapci, Zehra; Linjordet, Roar; Schnürer, Anna; Morken, John

    2014-04-01

    The effects of recirculating the liquid fraction of the digestate during mesophilic anaerobic co-digestion of steam-exploded Salix and cow manure were investigated in laboratory-scale continuously stirred tank reactors. An average organic loading rate of 2.6 g VS L(-1) d(-1) and a hydraulic retention time (HRT) of 30 days were employed. Co-digestion of Salix and manure gave better methane yields than digestion of manure alone. Also, a 16% increase in the methane yield was achieved when digestate was recirculated and used instead of water to dilute the feedstock (1:1 dilution ratio). The reactor in which the larger fraction of digestate was recirculated (1:3 dilution ratio) gave the highest methane yields. Ammonia and volatile fatty acids did not reach inhibitory levels, and some potentially inhibitory compounds released during steam explosion (i.e., furfural and 5-hydroxy methyl furfural) were only detected at trace levels throughout the entire study period. However, accumulation of solids, which was more pronounced in the recycling reactors, led to decreased methane yields in those systems after three HRTs. Refraining from the use of fresh water to dilute biomass with a high-solids content and obtaining a final digestate with increased dry matter content might offer important economic benefits in full-scale processes. To ensure long-term stability in such an approach, it would be necessary to optimize separation of the fraction of digestate to be recirculated and also perform proper monitoring to avoid accumulation of solids. PMID:24534902

  20. Mass balance of pharmaceutical and personal care products in a pilot-scale single-sludge system: influence of T, SRT and recirculation ratio.

    PubMed

    Suárez, Sonia; Reif, Rubén; Lema, Juan M; Omil, Francisco

    2012-09-01

    The influence of operation condition on the fate of 16 pharmaceutical and personal care products (PPCPs) in a single-sludge nitrifying/denitrifying pilot plant was assessed. Volatilisation, sorption and degradation were included in the mass balances to determine the most relevant removal mechanisms during PPCP treatment. Sludge retention time (SRT) was an important factor for the removal of compounds that significantly sorb onto sludge, as ethinylestradiol, whose removal increased 11% when working at SRT above 20 d. The internal recirculation ratio was significant for the removal of moderately biodegradable compounds, as citalopram. The positive effect of operating at warmer temperatures was particularly significant for two antibiotics, implying a 30% increase in their transformations. In the case of naproxen, an influence of sludge acclimation and concentration was observed, leading to removal efficiencies from 27% to 99%. Concerning removal mechanisms, most compounds were removed due to biotransformation, although for fragrances sorption and volatilisation played a role. PMID:22732303

  1. Solar hot-water system

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Design data brochure describes domestic solar water system that uses direct-feed system designed to produce 80 gallons of 140 F hot water per day to meet needs of single family dwelling. Brochure also reviews annual movements of sun relative to earth and explains geographic considerations in collector orientation and sizing.

  2. Water Treatment Technology - Distribution Systems.

    ERIC Educational Resources Information Center

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on distribution systems provides instructional materials for six competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: types of pipe for distribution systems, types…

  3. COMMUNITY WATER SYSTEM SURVEY (CWSS)

    EPA Science Inventory

    Resource Purpose: The CWSS is a national random sample of approximately 2,000 community water systems. The primary purpose of the CWSS is to provide OGWDW with data on the financial and operating characteristics of water systems. This information is used to support the o...

  4. The Binary Cooling Tower Process: An Energy Conserving Water Reuse Technology 

    E-print Network

    Lancaster, R. L.; Sanderson, W. G.; Cooke, R. L., Jr.

    1981-01-01

    often system energy efficiency due to heat exchanger performance losses between maintenance cycles. When brackish or contaminated recirculated cooling water is the primary coolant on the tubeside of a standard shell and tube heat exchanger... the initial capital cost of the heat exchanger from 17% to 58%. A primary coolant such as brackish or contam inated recirculated cooling water, requires the designer to select high-fouling coefficients to meet the design performance criteria over...

  5. Conceptual design description for the tritium recovery system for the US ITER (International Thermonuclear Experimental Reactor) Li sub 2 O\\/Be water cooled blanket

    Microsoft Academic Search

    P. A. Finn; D. K. Sze; R. G. Clemmer

    1990-01-01

    The tritium recovery system for the US ITER LiâO\\/Be water cooled blanket processes two separate helium purge streams to recover tritium from the LiâO zones and the Be zones of the blanket, to process the waste products, and to recirculate the helium back to the blanket. The components are selected to minimize the tritium inventory of the recovery system, and

  6. Conceptual design description for the tritium recovery system for the US ITER Li sub 2 O\\/Be water cooled blanket

    Microsoft Academic Search

    P. A. Finn; D. K. Sze; R. G. Clemmer

    1990-01-01

    The tritium recovery system for the US ITER LiâO\\/Be water cooled blanket processes two separate helium purge streams to recovery tritium from the LiâO zones and the Be zones of the blanket, to process the waste products, and to recirculate the helium back to the blanket. The components are selected to minimize the tritium inventory of the recovery system, and

  7. Effects of EGR, water/N2/CO2 injection and oxygen enrichment on the availability destroyed due to combustion for a range of conditions and fuels 

    E-print Network

    Sivadas, Hari Shanker

    2009-06-02

    This study was directed at examining the effects of exhaust gas recirculation (EGR), water/N2/CO2 injections and oxygen enrichment on availability destroyed because of combustion in simple systems like those of constant pressure and constant volume...

  8. Continuous Commissioning of a Central Chilled Water & Hot Water System 

    E-print Network

    Deng, S.; Turner, W. D.; Batten, T.; Liu, M.

    2000-01-01

    A central chilled water / hot water system provides cooling / heating energy from central utility plants to multiple customers (buildings) through campus distribution loops. To effectively transport the chilled water and hot water to the buildings...

  9. Water Supply Infrastructure System Surety

    SciTech Connect

    EKMAN,MARK E.; ISBELL,DARYL

    2000-01-06

    The executive branch of the United States government has acknowledged and identified threats to the water supply infrastructure of the United States. These threats include contamination of the water supply, aging infrastructure components, and malicious attack. Government recognition of the importance of providing safe, secure, and reliable water supplies has a historical precedence in the water works of the ancient Romans, who recognized the same basic threats to their water supply infrastructure the United States acknowledges today. System surety is the philosophy of ''designing for threats, planning for failure, and managing for success'' in system design and implementation. System surety is an alternative to traditional compliance-based approaches to safety, security, and reliability. Four types of surety are recognized: reactive surety; proactive surety, preventative surety; and fundamental, inherent surety. The five steps of the system surety approach can be used to establish the type of surety needed for the water infrastructure and the methods used to realize a sure water infrastructure. The benefit to the water industry of using the system surety approach to infrastructure design and assessment is a proactive approach to safety, security, and reliability for water transmission, treatment, distribution, and wastewater collection and treatment.

  10. Cyclone reactor with internal separation and axial recirculation

    DOEpatents

    Becker, Frederick E. (Reading, MA); Smolensky, Leo A. (Concord, MA)

    1989-01-01

    A cyclone combustor apparatus contains a circular partition plate containing a central circular aperture. The partition plate divides the apparatus into a cylindrical precombustor chamber and a combustor chamber. A coal-water slurry is passed axially into the inlet end of the precombustor chamber, and primary air is passed tangentially into said chamber to establish a cyclonic air flow. Combustion products pass through the partition plate aperture and into the combustor chamber. Secondary air may also be passed tangentially into the combustor chamber adjacent the partition plate to maintain the cyclonic flow. Flue gas is passed axially out of the combustor chamber at the outlet end and ash is withdrawn tangentially from the combuston chamber at the outlet end. A first mixture of flue gas and ash may be tangentially withdrawn from the combustor chamber at the outlet end and recirculated to the axial inlet of the precombustor chamber with the coal-water slurry. A second mixture of flue gas and ash may be tangentially withdrawn from the outlet end of the combustor chamber and passed to a heat exchanger for cooling. Cooled second mixture is then recirculated to the axial inlet of the precombustor chamber. In another embodiment a single cyclone combustor chamber is provided with both the recirculation streams of the first mixture and the second mixture.

  11. Research on leachate recirculation from different types of landfills

    SciTech Connect

    Wang Qi [Research Institute of Solid Waste Management, Chinese Research Academy of Environmental Sciences, No. 8 of Dayangfang, Chaoyang District, Beijing 100012 (China) and Faculty of Engineering, Fukuoka University, 8-19-1 Nanakuma, Johnan-ku, Fukuoka 814-0180 (Japan)]. E-mail: wangqi@craes.org.cn; Matsufuji, Yasushi [Faculty of Engineering, Fukuoka University, 8-19-1 Nanakuma, Johnan-ku, Fukuoka 814-0180 (Japan); Dong Lu [Research Institute of Solid Waste Management, Chinese Research Academy of Environmental Sciences, No. 8 of Dayangfang, Chaoyang District, Beijing 100012 (China); Huang Qifei [Research Institute of Solid Waste Management, Chinese Research Academy of Environmental Sciences, No. 8 of Dayangfang, Chaoyang District, Beijing 100012 (China); Hirano, Fumiaki [Faculty of Engineering, Fukuoka University, 8-19-1 Nanakuma, Johnan-ku, Fukuoka 814-0180 (Japan); Tanaka, Ayako [Faculty of Engineering, Fukuoka University, 8-19-1 Nanakuma, Johnan-ku, Fukuoka 814-0180 (Japan)

    2006-07-01

    Landfills can produce a great amount of leachate containing highly concentrated organic matter. This is especially true for the initial leachate from landfilled municipal solid wastes (MSW) that generally has concentrations of COD{sub Cr} and BOD{sub 5} up to 80,000 and 50,000 mg/L, respectively. The leachate could be disposed by means of recirculating technique, which decomposes the organics through the action of proliferating microorganisms and thereby purifies the leachate, and simultaneously accelerates organic decomposition through water saturation control. Data from experimental results indicated that leachate recirculating could reduce the organic concentration considerably, with a maximum reduction rate of COD{sub Cr} over 95%; and, using a semi-aerobic process, NH{sub 3}-N concentration of treated leachate could be under 10 mg/L. In addition, the organic concentration in MSW decreased greatly.

  12. Operational Management System for Regulated Water Systems

    NASA Astrophysics Data System (ADS)

    van Loenen, A.; van Dijk, M.; van Verseveld, W.; Berger, H.

    2012-04-01

    Most of the Dutch large rivers, canals and lakes are controlled by the Dutch water authorities. The main reasons concern safety, navigation and fresh water supply. Historically the separate water bodies have been controlled locally. For optimizating management of these water systems an integrated approach was required. Presented is a platform which integrates data from all control objects for monitoring and control purposes. The Operational Management System for Regulated Water Systems (IWP) is an implementation of Delft-FEWS which supports operational control of water systems and actively gives advice. One of the main characteristics of IWP is that is real-time collects, transforms and presents different types of data, which all add to the operational water management. Next to that, hydrodynamic models and intelligent decision support tools are added to support the water managers during their daily control activities. An important advantage of IWP is that it uses the Delft-FEWS framework, therefore processes like central data collection, transformations, data processing and presentation are simply configured. At all control locations the same information is readily available. The operational water management itself gains from this information, but it can also contribute to cost efficiency (no unnecessary pumping), better use of available storage and advise during (water polution) calamities.

  13. Digital feedwater and recirculation flow control for GPUN Oyster Creek

    SciTech Connect

    Burjorjee, D. (Atomic Energy of Canada Ltd., Mississauga, Ontario (Canada)); Gan, B. (GPU Nuclear Corp., Parsippany, NJ (United States))

    1992-01-01

    This paper describes the digital system for feedwater and recirculation control that GPU Nuclear will be installing at Oyster Creek during its next outage - expected circa December 1992. The replacement was motivated by considerations of reliability and obsolescence - the analog equipment was aging and reaching the end of its useful life. The new system uses Atomic Energy of Canada Ltd.'s software platform running on dual, redundant, industrial-grade 386 computers with opto-isolated field input/output (I/O) accessed through a parallel bus. The feedwater controller controls three main feed regulating valves, two low flow regulating valves, and two block valves. The recirculation controller drives the five scoop positioners of the hydraulic couplers. The system also drives contacts that lock up the actuators on detecting an open circuit in their current loops.

  14. Gas turbine combustor stabilization by heat recirculation

    NASA Technical Reports Server (NTRS)

    Ganji, A.; Short, J.; Branch, M. C.; Oppenheim, A. K.

    1975-01-01

    The feasibility of heat recirculation for stabilization of lean mixtures and emission reduction has been studied in detail for a typical aircraft gas turbine combustor. Thermodynamic calculations have indicated temperature and heat recirculation rates for operation of the combustor over a range of combustion zone equivalence ratios and for varying modes of desired engine operation. Calculations indicate the feasibility of stabilizing the combustion zone at equivalence ratios as low as 0.2 with achievable heat recirculation rates. Detailed chemical kinetic calculations suggest that combustor heat release is maintained with reaction completion substantially before the NO forming reactions, even though CO is rapidly oxidized in this same region.

  15. Lattice Design for the LHEC Recirculating Linac

    SciTech Connect

    Sun, Yipeng; /CERN; Eide, Anders; /CERN; Zimmermann, Frank; /CERN; Adolphsen, Chris; /SLAC

    2011-05-20

    In this paper, we present a lattice design for the Large Hadron Electron Collider (LHeC) recirculating linac. The recirculating linac consists of one roughly 3-km long linac hosting superconducting RF (SRF) accelerating cavities, two arcs and one transfer line for the recirculation. In two passes through a pulsed SRF linac the electron beam can get a maximum energy of 140 GeV. Alternatively, in the Energy Recovery Linac (ERL) option the beam passes through a CW linac four times (two passes for acceleration and two for deceleration) for a maximum energy of 60 GeV.

  16. CASE FOR DRINKING WATER SYSTEMS

    EPA Science Inventory

    The purpose of the study was to present a tool useful to water utilities that not only could analyze historical distribution system reliability data, but also provide a flexible and expandable mechanism for record-keeping enabling overall management of water work's facilities and...

  17. A Guide to Private Water Systems in

    E-print Network

    Boyer, Elizabeth W.

    , Corrosive Water Problems, Lead in Drinking Water, Iron and Manganese in Private Water Systems, Hydrogen Water Problems, Lead in Drinking Water, Iron and Manganese in Private Water Systems, Hydrogen Sulfide Clark--Glossary Stephanie Clemens--Spring Development and Protection, Testing Your Drinking Water, Tips

  18. SMALL DRINKING WATER SYSTEMS RESEARCH

    EPA Science Inventory

    There are 159,796 Community Water Systems (CWSs) in the United States. Ninety-three percent of CWSs are considered very small to medium-sized systems that serve roughly 19% of the CWS population. In contrast, large to very large systems comprise just 7% of CWSs, but serve 81% of ...

  19. North Sea produced water systems

    SciTech Connect

    Bond, C.R.

    1985-01-01

    North Sea platform produced water systems were designed up to 10 years ago utilising plant largely developed for other industries. Generally the systems were designed without adequate knowledge of the produced water itself or the flow-rates. Many fields are now experiencing injection water break-through and consequently far greater flow rates than envisaged. By reference to Britoil's Thistle and Beatrice platforms, this paper describes some of the short-comings of systems, the resultant modifications and extensions, and performance data before and after modifications. The paper addresses the fundamentals of produced water treatment technology and presents operating data from: a. Laboratory model testing and offshore pilot trials of cartridge coalescers; b. Modified tilted plate assemblies; c. Induced and dissolved gas processes; d. System interactions and practical operating problems.

  20. Effect of cooling water impurities on deposit control polymer performance

    Microsoft Academic Search

    Z. Amjad; R. W. Zuhl; J. F. Zibrida

    2000-01-01

    The performance of polymeric inhibitors in treating recirculating cooling water systems is influenced by many factors, including pH, temperature, makeup water quality, and heat exchanger metallurgy. Impurities such as metal ions and suspended matter impact the performance of polymeric inhibitors used in phosphate-based treatment cooling water programs.

  1. Effect of cooling water impurities on deposit control polymer performance

    SciTech Connect

    Amjad, Z.; Zuhl, R.W.; Zibrida, J.F.

    2000-05-01

    The performance of polymeric inhibitors in treating recirculating cooling water systems is influenced by many factors, including pH, temperature, makeup water quality, and heat exchanger metallurgy. Impurities such as metal ions and suspended matter impact the performance of polymeric inhibitors used in phosphate-based treatment cooling water programs.

  2. Systems and Components Fuel Delivery System, Water Delivery System, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Systems and Components - Fuel Delivery System, Water Delivery System, Derrick Crane System, and Crane System Details - Marshall Space Flight Center, F-1 Engine Static Test Stand, On Route 565 between Huntsville and Decatur, Huntsville, Madison County, AL

  3. Ephesus Municipal Water System Analysis

    NSDL National Science Digital Library

    Dora P. Crouch

    1997-12-05

    This project examines the entire water system of an ancient city, including supply, distribution, use, and drainage. Until now, individual water system elements have been studied as archaeological objects, but infrequently subjected to analysis by such disciplines as fluids engineering and urban history. This work is part of two larger long-term studies, the first concerning the relationship between physical setting and urban growth in the Greco-Roman world, and the second a comparative study of Old and New World water management techniques in the pre-modern period.

  4. Clean Water Systems in Mexico

    NSDL National Science Digital Library

    2010-08-31

    In this video segment adapted from Rx for Survival, learn about the importance of clean water and sanitation systems. Hear the story of how, in the early 1990s, Mexico's entry into a North American trade agreement was threatened by a cholera epidemic. Find out how the Mexican government rebuilt the water and sanitation system to stop the spread of the disease and how the investment in clean water helped the country win the trade agreement. A background essay, discussion questions, and standards correlations are also provided.

  5. Water in clay-water systems (1) Philip F. LOW

    E-print Network

    Paris-Sud XI, Université de

    Water in clay-water systems (1) Philip F. LOW Department of Agronomy, Purdue University. Agric. Exp. Stn., West Lafayette, IN 47907, U.S.A. SUMMARY The swelling of clay-water systems and the thermodynamic, hydrodynamic and spectroscopic properties of water in these systems are discussed. The swelling

  6. Ultrapure Water System for Hemodialysis Therapy

    ClinicalTrials.gov

    2011-07-21

    The Change of Biomarkers CRP, CBC With the Use of Ultra Pure Water System for; Hemodialysis.; The Rate of Adverse Events Such as Hypotension During Hemodialysis Therapy With Ultra Pure Water; System as Compared to Conventional Water System.

  7. Identification of optimum potassium nutrition of greenhouse plants grown in recirculating subirrigation 

    E-print Network

    Blessington, Trisha R.

    2002-01-01

    . Experiment 3 compared the optimum K fertilizer rates of vinca 'Pacifica Red' grown in recirculating subirrigation and top water. The plants grew the best in subirrigation at 2 mM K and in top water at 4 mM K. Fertilizer salt stratification occurred...

  8. MINIMIZATION OF WATER USE IN LEAFY VEGETABLE WASHERS

    EPA Science Inventory

    This project was undertaken to construct and test an improved leafy greens washing system employing water recirculation, to characterize the quality of the wash water and waste stream and to make comparisons to conventional washers. The prototype system produced a cleaner product...

  9. Industrial oven having air recirculating means for minimizing heat loss

    SciTech Connect

    Nowack, W.C.

    1981-11-03

    An industrial oven is described in which articles to be heat treated are carried by a conveyor through a heated tunnel space in a tunnel structure which has end walls with access openings, such oven comprising a nozzle directed downwardly into the tunnel space at an inclined angle across at least one access opening, an exhaust opening communicating with the tunnel space in the vicinity of the upper portion of such access opening, and air handling means for withdrawing hot air from the tunnel space through said exhaust opening while blowing hot air into the tunnel space through said nozzle for minimizing the escape of hot air through such access opening. The air handling means may take the form of a recirculating blower connected between the exhaust opening and the nozzle. The oven may have an air heating and recirculating system which withdraws air from the tunnel space. Instead of providing a separate recirculating blower, exhaust and supply ducts may be connected to the intake and discharge sides of such system and may extend to the exhaust opening and the nozzle to circulate hot air out of the tunnel space through the exhaust opening and into the tunnel space through the nozzle.

  10. An integrated closed system for fish-plankton aquaculture in Amazonian fresh water.

    PubMed

    Gilles, S; Ismiño, R; Sánchez, H; David, F; Núñez, J; Dugué, R; Darias, M J; Römer, U

    2014-05-22

    A prototype of an integrated closed system for fish-plankton aquaculture was developed in Iquitos (Peruvian Amazonia) in order to cultivate the Tiger Catfish, Pseudoplatystoma punctifer (Castelnau, 1855). This freshwater recirculating system consisted of two linked sewage tanks with an intensive rearing unit (a cage) for P. punctifer placed in the first, and with a fish-plankton trophic chain replacing the filters commonly used in clear water closed systems. Detritivorous and zooplanktivorous fishes (Loricariidae and Cichlidae), maintained without external feeding in the sewage volume, mineralized organic matter and permitted the stabilization of the phytoplankton biomass. Water exchange and organic waste discharge were not necessary. In this paper we describe the processes undertaken to equilibrate this ecosystem: first the elimination of an un-adapted spiny alga, Golenkinia sp., whose proliferation was favored by the presence of a small rotifer, Trichocerca sp., and second the control of this rotifer proliferation via the introduction of two cichlid species, Acaronia nassa Heckel, 1840 and Satanoperca jurupari Heckel, 1840, in the sewage part. This favored some development of the green algae Nannochloris sp. and Chlorella sp. At that time we took the opportunity to begin a 3-month rearing test of P. punctifer. The mean specific growth rate and feed conversion ratio (FCR) of P. punctifer were 1.43 and 1.27, respectively, and the global FCR, including fish in the sewage part, was 1.08. This system has proven to be suitable for growing P. punctifer juveniles out to adult, and provides several practical advantages compared with traditional recirculating clear water systems, which use a combination of mechanical and biological filters and require periodic waste removal, leading to water and organic matter losses. PMID:24849417

  11. Optimization of Chilled Water Systems 

    E-print Network

    Gidwani, B. N.

    1987-01-01

    consumption. Installing variable-speed drives on each pump motor makes this possible. Variable speed drive types include, but are"not limited to, the following: ? Variable voltage. ? Eddy current clutch. ? Hydraulic clutch. By controlling motor speed..., only the required quantities of chilled water ar'e circulated. The required chilled water quantity is a function of the total head seen by the pump (Figure 11). Monitoring this pressure with a micro-processor based control system allOWS a speed...

  12. Information Sources for Small Water Systems

    E-print Network

    Dozier, Monty; Theodori, Gene L.; Jensen, Ricard

    2007-02-19

    Managers of small waters systems must have information about a variety of topics. This publication lists essential printed and electronic resources on disaster preparedness, national drinking water standards, private water well management, water...

  13. Evidence for sediment recirculation on an ebb-tidal delta of the East Frisian barrier-island system, southern North Sea

    NASA Astrophysics Data System (ADS)

    Son, Chang Soo; Flemming, Burghard W.; Bartholomä, Alexander

    2011-04-01

    The Otzum ebb-tidal delta, located between Langeoog and Spiekeroog islands along the East Frisian barrier-island coast, southern North Sea, was investigated with respect to its morphological evolution, sediment distribution patterns and internal sedimentary structures. Bathymetric charts reveal that, over the last 50 years, the size of the Otzum ebb-tidal delta has slightly shrunk, while sediment has accreted on the ebb-delta lobe to the east of the main inlet channel (west of Spiekeroog). Swash bars superimposed on the eastern ebb-tidal shoal (Robben Plate) have migrated south or south-eastwards, i.e. towards the inlet throat. The main ebb-delta body is composed of fine quartz sand, whereas the superimposed swash bars and the inlet channel bed consist of medium-grained quartz sand containing high proportions of coarser bioclastic material. Internal sedimentary structures in short box-cores (up to 30 cm long) are dominated by flood-oriented cross-beds. Longer vibro-cores (up to 1.5 m long) show that, at depth, the sediment is dominated by storm-generated parallel (upper plane bed) laminations with intercalated shell layers and dune cross-bedding. The cross-bedded sands in both box-cores and vibro-cores from the ebb-delta shoal predominantly dip towards the south or southeast, indicating transport towards the inlet throat by the flood current. The observations demonstrate that, contrary to previous contentions, the sediments of the highly mobile swash bars do not bypass the inlet but are instead being continually recirculated by the combined action of tidal currents and waves. In this model, the cycle begins with both fine and medium sands, including shell hash, being transported seawards in the main ebb channel until they reach the shallow ebb-delta front. From here, the sediment is pushed onto the eastern ebb-delta shoal by the flood current assisted by waves, becoming strongly size-sorted in the process. The medium sands together with the shell hash are formed into swash bars which migrate along arcuate paths over a base of fine sand back to the main ebb channel located south of the ebb delta. By the same token, the fine sand between the swash bars is transported south-eastwards by the flood current in the form of small dunes until it cascades into the large flood channel located to the west of Spiekeroog. From here, the fine sand is fed back into the main ebb channel, thus completing the cycle. No evidence was found on the ebb delta for alongshore sediment bypassing.

  14. Water availability under the Texas water rights system

    Microsoft Academic Search

    Ralph A. Wurbs

    1997-01-01

    Texas recently established a surface water rights permit system, similar to those of other western states. A simulation study of the Brazos River Basin identified issues and concerns that illustrate the practical complexities of administering and modeling a water allocation system. Key considerations involve sharing of limited supplies by numerous water users during drought, reservoir storage priorities, multiple-reservoir system operations,

  15. Experiments With Recirculating Target for F-18 Production

    NASA Astrophysics Data System (ADS)

    Kiselev, M. Y.

    2003-08-01

    Approximately 10 ml of O-18 water was loaded in an apparatus containing a 5 ml storage vessel, pump, silver target attached to a cyclotron, filter, backpressure regulator, conductivity meter, several valves and ion exchange cartridges. The water was continuously pumped through the target during proton bombardment at a rate 5 ml/min. Continuous irradiation with beam current ranging from 10 to 50 uA was conducted while pressure, temperature and conductivity were continuously monitored. The results indicate that recirculating of the target water can increase production of F-18 in relation to consumed O-18 water material. It can also increase productivity by eliminating idle periods for re-filling the target. A backpressure regulator can precisely control target pressure. This method also allows for continuous monitoring of the target material temperature, pressure, conductivity and accumulated radioactivity. Results of these observations provide important information about target performance and physical processes taking place inside the target.

  16. WATER QUALITY MODELING DISTRIBUTION SYSTEMS

    EPA Science Inventory

    This paper reviews the use of models for predicting water quality in distribution systems. esults of an extensive field study conducted by the USEPA and North Penn Mater Authority are examined. A case study of the model application to a waterborne disease outbreak in Cabool, Miss...

  17. Water pressure booster system selection

    SciTech Connect

    Anderson, G.W.

    1983-01-01

    Offers guidelines on type of water pumping system to be used (constant or variable speed) and system split (breakdown of 100% system load into 2 or more pumps, with number and type of pumps taken into account). Variable speed control (e.g. SCR type) is justified where an extreme variable in suction pressure exists. Experience based on power studies, metering, and observation of various installations dictates a ''normal'' system split of 3 pumps, rated 25, 55 and 55% of peak demand. A specific application or system size may merit modification, but each should have the capability of: 80% minimum residual capacity and use of a ''workhorse'' lead pump to handle low flow requirements. System sizing is the primary consideration in the proper selection of a booster system.

  18. Effect of makeup water properties on the condenser fouling in power planr cooling system

    SciTech Connect

    Safari, I.; Walker, M.; Abbasian, J.; Arastoopour, H.; Hsieh, M-K.; Dzombak, D.; Miller, D.

    2011-01-01

    The thermoelectric power industry in the U.S. uses a large amount of fresh water. As available freshwater for use in thermoelectric power production becomes increasingly limited, use of nontraditional water sources is of growing interest. Utilization of nontraditional water, in cooling systems increases the potential for mineral precipitation on heat exchanger surfaces. In that regard, predicting the accelerated rate of scaling and fouling in condenser is crucial to evaluate the condenser performance. To achieve this goal, water chemistry should be incorporated in cooling system modeling and simulation. This paper addresses the effects of various makeup water properties on the cooling system, namely pH and aqueous speciation, both of which are important factors affecting the fouling rate in the main condenser. Detailed modeling of the volatile species desorption (i.e. CO{sub 2} and NH{sub 3}), the formation of scale in the recirculating system, and the relationship between water quality and the corresponding fouling rates is presented.

  19. Total Water Management, the New Paradigm for Urban Water Systems

    EPA Science Inventory

    There is a growing need for urban water managers to take a more holistic view of their water resource systems as population growth, urbanization, and current resource management practices put different stresses on local water resources and urban infrastructure. Total Water Manag...

  20. WATER DISTRIBUTION SYSTEM OPERATION: APPLICATION OF

    E-print Network

    Mays, Larry W.

    CHAPTER 5 WATER DISTRIBUTION SYSTEM OPERATION: APPLICATION OF SIMULATED ANNEALING Fred E. Goldman Arizona State University, Tempe, Arizona 5.1 INTRODUCTION The operation of water distribution systems affects the water quality in these systems. EPA regulations require that water quality be maintained

  1. Generation and maintenance of recirculations by Gulf Stream instabilities

    E-print Network

    Beliakova, Natalia Yurievna, 1967-

    1999-01-01

    This thesis studies the problems of generation and maintenance of recirculations by Gulf Stream instabilities. Observations show that the horizontal structure of the jet and its recirculations suffer significant changes ...

  2. ELECTROPHORESIS GEL BUFFER RECIRCULATOR FOR UNDER 20 DOLLARS

    EPA Science Inventory

    Procedures requiring extended periods of electrophoresis frequently require recirculation of the get buffer in order to reduce gel artifacts. ere we describe a recirculation device which can be built inexpensively and will fit many different model get boxes....

  3. Implementation of new non-chrome cooling water chemistry

    Microsoft Academic Search

    D. E. Shannon; M. D. Watson

    1988-01-01

    Environmental concerns regarding the use of chromate based corrosion control programs in industrial recirculating cooling water systems, are once again a priority topic. The environmental protection agency identified, first, surface water contamination, then chromium containing solid waste disposal and most recently atmospheric and even groundwater contamination as matters for serious consideration. Calgon's development of a new, patented terpolymer allows the

  4. Water monitor system: Phase 1 test report

    NASA Technical Reports Server (NTRS)

    Taylor, R. E.; Jeffers, E. L.

    1976-01-01

    Automatic water monitor system was tested with the objectives of assuring high-quality effluent standards and accelerating the practice of reclamation and reuse of water. The NASA water monitor system is described. Various components of the system, including the necessary sensors, the sample collection system, and the data acquisition and display system, are discussed. The test facility and the analysis methods are described. Test results are reviewed, and recommendations for water monitor system design improvement are presented.

  5. Recirculation as a Form of Conservation.

    ERIC Educational Resources Information Center

    Gordon, Jeffrey J.

    1982-01-01

    Discusses nine forms of conservation practices: sustained yield, repair, careful use, greater efficiency, lower consumption, doing without, substitution, new resources, and recycling. Suggests recirculation (saving goods from discard and from being broken down in a new manufacturing stage) as a 10th form of conservation practice. (Author/JN)

  6. Recirculating natural convection solar energy collector

    Microsoft Academic Search

    Soleau; B. S. Jr

    1979-01-01

    Recirculating natural convection solar energy collectors are disclosed. In one species of the invention, the collector comprises an insulated housing, a cover of glass or other suitable transparent material, a transparent plate of glass or other suitable material mounted inside said housing and spaced apart from the cover, a heat absorber mounted inside the housing and spaced apart from the

  7. Pilot-scale cooling tower to evaluate corrosion, scaling, and biofouling control strategies for cooling system makeup water.

    PubMed

    Chien, S H; Hsieh, M K; Li, H; Monnell, J; Dzombak, D; Vidic, R

    2012-02-01

    Pilot-scale cooling towers can be used to evaluate corrosion, scaling, and biofouling control strategies when using particular cooling system makeup water and particular operating conditions. To study the potential for using a number of different impaired waters as makeup water, a pilot-scale system capable of generating 27,000 kJ?h heat load and maintaining recirculating water flow with a Reynolds number of 1.92 × 10(4) was designed to study these critical processes under conditions that are similar to full-scale systems. The pilot-scale cooling tower was equipped with an automatic makeup water control system, automatic blowdown control system, semi-automatic biocide feeding system, and corrosion, scaling, and biofouling monitoring systems. Observed operational data revealed that the major operating parameters, including temperature change (6.6 °C), cycles of concentration (N = 4.6), water flow velocity (0.66 m?s), and air mass velocity (3660 kg?h m(2)), were controlled quite well for an extended period of time (up to 2 months). Overall, the performance of the pilot-scale cooling towers using treated municipal wastewater was shown to be suitable to study critical processes (corrosion, scaling, biofouling) and evaluate cooling water management strategies for makeup waters of complex quality. PMID:22380105

  8. Pilot-scale cooling tower to evaluate corrosion, scaling, and biofouling control strategies for cooling system makeup water

    NASA Astrophysics Data System (ADS)

    Chien, S. H.; Hsieh, M. K.; Li, H.; Monnell, J.; Dzombak, D.; Vidic, R.

    2012-02-01

    Pilot-scale cooling towers can be used to evaluate corrosion, scaling, and biofouling control strategies when using particular cooling system makeup water and particular operating conditions. To study the potential for using a number of different impaired waters as makeup water, a pilot-scale system capable of generating 27 000 kJ/h heat load and maintaining recirculating water flow with a Reynolds number of 1.92 × 104 was designed to study these critical processes under conditions that are similar to full-scale systems. The pilot-scale cooling tower was equipped with an automatic makeup water control system, automatic blowdown control system, semi-automatic biocide feeding system, and corrosion, scaling, and biofouling monitoring systems. Observed operational data revealed that the major operating parameters, including temperature change (6.6 °C), cycles of concentration (N = 4.6), water flow velocity (0.66 m/s), and air mass velocity (3660 kg/h m2), were controlled quite well for an extended period of time (up to 2 months). Overall, the performance of the pilot-scale cooling towers using treated municipal wastewater was shown to be suitable to study critical processes (corrosion, scaling, biofouling) and evaluate cooling water management strategies for makeup waters of complex quality.

  9. Water: Life's Elixir in the Solar System

    NSDL National Science Digital Library

    This article discusses the possible occurrence of water in our solar system. Topics include the necessity of liquid water for life, distribution of water throughout the solar system, and the possibility that there may be liquid water on Mars or on some of Jupiter's moons.

  10. EFFICIENCIES AND WATER LOSSES OF IRRIGATION SYSTEMS

    Microsoft Academic Search

    Danny H. Rogers; Freddie R. Lamm

    Efficiency ratings receive a lot of attention. We like efficient engines, air conditioners, water heaters and furnaces. Conservationists like efficient water systems that deliver water for its intended use without loss due to leakage, spills or contamina-tion. Since irrigation is the largest appropriated water user in Kansas, irrigation systems also receive merit based on how efficient they are reported to

  11. Water reactive hydrogen fuel cell power system

    DOEpatents

    Wallace, Andrew P; Melack, John M; Lefenfeld, Michael

    2014-11-25

    A water reactive hydrogen fueled power system includes devices and methods to combine reactant fuel materials and aqueous solutions to generate hydrogen. The generated hydrogen is converted in a fuel cell to provide electricity. The water reactive hydrogen fueled power system includes a fuel cell, a water feed tray, and a fuel cartridge to generate power for portable power electronics. The removable fuel cartridge is encompassed by the water feed tray and fuel cell. The water feed tray is refillable with water by a user. The water is then transferred from the water feed tray into the fuel cartridge to generate hydrogen for the fuel cell which then produces power for the user.

  12. Water reactive hydrogen fuel cell power system

    DOEpatents

    Wallace, Andrew P; Melack, John M; Lefenfeld, Michael

    2014-01-21

    A water reactive hydrogen fueled power system includes devices and methods to combine reactant fuel materials and aqueous solutions to generate hydrogen. The generated hydrogen is converted in a fuel cell to provide electricity. The water reactive hydrogen fueled power system includes a fuel cell, a water feed tray, and a fuel cartridge to generate power for portable power electronics. The removable fuel cartridge is encompassed by the water feed tray and fuel cell. The water feed tray is refillable with water by a user. The water is then transferred from the water feed tray into a fuel cartridge to generate hydrogen for the fuel cell which then produces power for the user.

  13. WATER QUALITY EFFECTS RELATED TO BLENDING WATERS IN DISTRIBUTION SYSTEMS

    EPA Science Inventory

    This study was conducted to evaluate the effects of blending two or more waters of different quality and to relate their composition to the corrosive effects and calcium carbonate deposition tendency of the water on distribution systems. The EPA mobile water quality monitoring la...

  14. Hybrid heat exchange for the compression capture of CO2 from recirculated flue gas

    SciTech Connect

    Oryshchyn, Danylo B.; Ochs, Thomas L.; Summers, Cathy A.

    2004-01-01

    An approach proposed for removal of CO2 from flue gas cools and compresses a portion of a recirculated flue-gas stream, condensing its volatile materials for capture. Recirculating the flue gas concentrates SOx, H2O and CO2 while dramatically reducing N2 and NOx, enabling this approach, which uses readily available industrial components. A hybrid system of indirect and direct-contact heat exchange performs heat and mass transfer for pollutant removal and energy recovery. Computer modeling and experimentation combine to investigate the thermodynamics, heat and mass transfer, chemistry and engineering design of this integrated pollutant removal (IPR) system.

  15. Monitoring systems for community water supplies

    NASA Technical Reports Server (NTRS)

    Taylor, R. E.; Brooks, R. R.; Jeffers, E. L.; Linton, A. T.; Poel, G. D.

    1978-01-01

    Water monitoring system includes equipment and techniques for waste water sampling sensors for determining levels of microorganisms, oxygen, chlorine, and many other important parameters. System includes data acquisition and display system that allows computation of water quality information for real time display.

  16. Stealthy Deception Attacks on Water SCADA Systems

    E-print Network

    Hu, Fei

    The Gignac Water SCADA System Modeling of Cascade Canal Pools Attacks on PI Control Limits on Stability and Detectability #12;Recapitulation from last year The Gignac Water SCADA System Modeling of Cascade Canal Pools last year The Gignac Water SCADA System Modeling of Cascade Canal Pools Attacks on PI Control Limits

  17. Beneficial effects on water management of simple hydraulic structures in wetland systems: the Vallevecchia case study, Italy.

    PubMed

    Carrer, G M; Bonato, M; Smania, D; Barausse, A; Comis, C; Palmeri, L

    2011-01-01

    Conflicting water uses in coastal zones demand integrated approaches to achieve sustainable water resources management, protecting water quality while allowing those human activities which rely upon aquatic ecosystem services to thrive. This case study shows that the creation and simple management of hydraulic structures within constructed wetlands can markedly reduce the non-point pollution from agriculture and, simultaneously, benefit agricultural activities, particularly during hot and dry periods. The Vallevecchia wetland system is based on a reclaimed 900 ha-large drainage basin in Northern Italy, where droughts recently impacted agriculture causing water scarcity and saltwater intrusion. Rainwater and drained water are recirculated inside the system to limit saltwater intrusion, provide irrigation water during dry periods and reduce the agricultural nutrient loads discharged into the bordering, eutrophic Adriatic Sea. Monitoring (2003-2009) of water quality and flows highlights that the construction (ended in 2005) of a gated spillway to control the outflow, and of a 200,000 m3 basin for water storage, dramatically increased the removal of nutrients within the system. Strikingly, this improvement was achieved with a minimal management effort, e.g., each year the storage basin was filled once: a simple management of the hydraulic structures would greatly enhance the system efficiency, and store more water to irrigate and limit saltwater intrusion. PMID:22053478

  18. THE WATER STRATEGY MAN DECISION SUPPORT SYSTEM

    Microsoft Academic Search

    Porta S. Donato

    The WaterStrategyMan project aims at supporting Decision Makers and Water Managers in multi-objective planning of water resource systems based on simulation of alternative scenarios of water availability and water demand and the application of problem-specific policy measures. Water strategies and management options, including structural and non-structural interventions, for Supply Enhancement, Demand Management and Institutional Policies are evaluated on the basis

  19. Mutualism between euryhaline tilapia Sarotherodon melanotheron heudelotii and Chlorella sp.—Implications for nano-algal production in warmwater phytoplankton-based recirculating systems

    Microsoft Academic Search

    Sylvain Gilles; Gérard Lacroix; Daniel Corbin; Ngansoumana Bâ; Carla Ibañez Luna; Jacob Nandjui; Allassane Ouattara; Ousséni Ouédraogo; Xavier Lazzaro

    2008-01-01

    The West-African euryhaline tilapia, Sarotherodon melanotheron heudelotii shift from visually feeding on zooplankton when juveniles to mostly filter feeding on phytoplankton when adults. When reared using an appropriate ration in intensive aquaculture systems, S. m. heudelotii also consume algal-based detritus, and contribute to sediment mineralization, clean up their environment, and ultimately stimulate and sustain algal growth. We analysed such practical

  20. Molecular Determinants Controlling Homeostatic Recirculation and Tissue-Specific Trafficking of Lymphocytes

    Microsoft Academic Search

    Toshiyuki Tanaka; Yukihiko Ebisuno; Naotoshi Kanemitsu; Eiji Umemoto; Bo-gie Yang; Myoung-ho Jang; Masayuki Miyasaka

    2004-01-01

    The homeostasis of the immune system is maintained by the recirculation of naïve lymphocytes through the secondary lymphoid tissues, such as the lymph nodes, Peyer’s patches, and spleen. Upon insult by pathogens or antigens, lymphocytes become activated, and the regulated trafficking of these cells results in the integration of systemic and regional immune responses. The exquisite specificity of such lymphocyte

  1. An Oil/Water disperser device for use in an oil content Monitor/Control system

    NASA Astrophysics Data System (ADS)

    Kempel, F. D.

    1985-07-01

    This patent application discloses an oil content monitor/control unit system, including an oil/water disperser device, which is configured to automatically monitor and control processed effluent from an associated oil/water separator so that if the processed effluent exceeds predetermine in-port or at-sea oil concentration lmits, it is either recirculated to an associated oil/water separator via a ship's bilge for additional processing, or diverted to a holding tank for storage. On the other hand, if the oil concentration of the processed effluent is less than predetermine in-port or at-sea limits, it is discharged overboard. The oil/water disperser device is configured to break up any oil present in the processed effluent into uniform droplets for more accurate sensing of the oil present in the processed effluent into uniform droplets for more accurate sensing of the oil-in-water concentration level thereof. The oil/water disperser device has a flow-actuated variable orifice configured into a spring-loaded polyethylene plunger which provides the uniform distribution of oil droplets.

  2. Electroporation System for Sterilizing Water

    NASA Technical Reports Server (NTRS)

    Schlager, Kenneth J.

    2005-01-01

    A prototype of an electroporation system for sterilizing wastewater or drinking water has been developed. In electroporation, applied electric fields cause transient and/or permanent changes in the porosities of living cells. Electroporation at lower field strengths can be exploited to increase the efficiency of chemical disinfection (as in chlorination). Electroporation at higher field strengths is capable of inactivating and even killing bacteria and other pathogens, without use of chemicals. Hence, electroporation is at least a partial alternative to chlorination. The transient changes that occur in micro-organisms at lower electric-field strengths include significantly increased uptake of ions and molecules. Such increased uptake makes it possible to achieve disinfection at lower doses of chemicals (e.g., chlorine or ozone) than would otherwise be needed. Lower doses translate to lower costs and reduced concentrations of such carcinogenic chemical byproducts as trichloromethane. Higher electric fields cause cell membranes to lose semipermeability and thereby become unable to function as selective osmotic barriers between the cells and the environment. This loss of function is the cause of the cell death at higher electric-field intensities. Experimental evidence does not indicate cell lysis but, rather, combined leaking of cell proteins out of the cells as well as invasion of foreign chemical compounds into the cells. The concept of electroporation is not new: it has been applied in molecular biology and genetic engineering for decades. However, the laboratory-scale electroporators used heretofore have been built around small (400-microliter) cuvettes, partly because the smallness facilitates the generation of electric fields of sufficient magnitude to cause electroporation. Moreover, most laboratory- scale electroporators have been designed for testing static water. In contrast, the treatment cell in the present system is much larger and features a flow-through geometry, such that electric fields strong enough to effect 99.9- percent disinfection can be applied to water flowing in a pipe.

  3. High Power Picosecond Laser Pulse Recirculation

    SciTech Connect

    Shverdin, M Y; Jovanovic, I; Semenov, V A; Betts, S M; Brown, C; Gibson, D J; Shuttlesworth, R M; Hartemann, F V; Siders, C W; Barty, C P

    2010-04-12

    We demonstrate a nonlinear crystal-based short pulse recirculation cavity for trapping the second harmonic of an incident high power laser pulse. This scheme aims to increase the efficiency and flux of Compton-scattering based light sources. We demonstrate up to 36x average power enhancement of frequency doubled sub-millijoule picosecond pulses, and 17x average power enhancement of 177 mJ, 10 ps, 10 Hz pulses.

  4. BIOFILM IN DRINKING WATER DISTRIBUTION SYSTEMS

    EPA Science Inventory

    Throughout the world there are millions of miles of water distribution pipe lines which provide potable water for use by individuals and industry. Some of these water distribution systems have been in service well over one hundred years. Treated water moving through a distributio...

  5. Sustainable Water Use System of Artesian Water in Alluvial Fan

    NASA Astrophysics Data System (ADS)

    Kishi, K.; Tsujimura, M.; Tase, N.

    2013-12-01

    The traditional water use system, developed with the intelligence of the local residents, usually takes advantage of local natural resources and is considered as a sustainable system, because of its energy saving(only forces of nature). For this reason, such kind of water use system is also recommended in some strategic policies for the purpose of a symbiosis between nature and human society. Therefore, it is important to clarify the relationship between human activities and water use systems. This study aims to clarify the mechanism of traditional water use processes in alluvial fan, and in addition, to investigate the important factors which help forming a sustainable water use system from the aspects of natural conditions and human activities. The study area, an alluvial fan region named Adogawa, is located in Shiga Prefecture, Japan and is in the west of Biwa Lake which is the largest lake in Japan. In this alluvial region where the land use is mainly occupied by settlements and paddy fields, a groundwater flowing well system is called "kabata" according to local tradition. During field survey, we took samples of groundwater, river water and lake water as well as measured the potential head of groundwater. The results showed that the upper boundary of flowing water was approximately 88m amsl, which is basically the same as the results reported by Kishi and Kanno (1966). In study area, a rapid increase of water pumping for domestic water use and melting snow during last 50 years, even if the irrigation area has decreased about 30% since 1970, and this fact may cause a decrease in recharge rate to groundwater. However, the groundwater level didn't decline based on the observed results, which is probably contributed by some water conservancy projects on Biwa Lake which maintained the water level of the lake. All the water samples are characterized by Ca-HCO3 type and similar stable isotopic value of ?D and ?18O. Groundwater level in irrigation season is higher than that in non-irrigation season, which indicates that groundwater level is apparently influenced by surface water. Some communities and NPOs working in this area maintain the "kabata" and canal for environment conservation. There are many rules for the local residents when using the water resources. For example, the use of detergents is prohibited for "kabata" users. The residents living upstream also should think of other groundwater users downstream. For this reason, it can be considered that the "kabata" water use method contributed to a symbiosis between ecosystem and human activity The study area case showed that the traditional water use system is useful for forming a sustainable groundwater flowing well use system.

  6. DETERIORATION OF DRINKING WATER DISTRIBUTION SYSTEMS

    EPA Science Inventory

    A frequently overlooked fact, but one that is becoming of increasing concern, is the effect that the drinking water delivery system can have on the quality of water received at the tap. Deterioration of aging water supply systems can result in pipeline failures, pressure losses, ...

  7. The impact of recirculation, ventilation and filters on secondary organic aerosols generated by indoor chemistry

    NASA Astrophysics Data System (ADS)

    Fadeyi, M. O.; Weschler, C. J.; Tham, K. W.

    This study examined the impact of recirculation rates (7 and 14 h -1), ventilation rates (1 and 2 h -1), and filtration on secondary organic aerosols (SOAs) generated by ozone of outdoor origin reacting with limonene of indoor origin. Experiments were conducted within a recirculating air handling system that serviced an unoccupied, 236 m 3 environmental chamber configured to simulate an office; either no filter, a new filter or a used filter was located downstream of where outdoor air mixed with return air. For otherwise comparable conditions, the SOA number and mass concentrations at a recirculation rate of 14 h -1 were significantly smaller than at a recirculation rate of 7 h -1. This was due primarily to lower ozone concentrations, resulting from increased surface removal, at the higher recirculation rate. Increased ventilation increased outdoor-to-indoor transport of ozone, but this was more than offset by the increased dilution of SOA derived from ozone-initiated chemistry. The presence of a particle filter (new or used) strikingly lowered SOA number and mass concentrations compared with conditions when no filter was present. Even though the particle filter in this study had only 35% single-pass removal efficiency for 100 nm particles, filtration efficiency was greatly amplified by recirculation. SOA particle levels were reduced to an even greater extent when an activated carbon filter was in the system, due to ozone removal by the carbon filter. These findings improve our understanding of the influence of commonly employed energy saving procedures on occupant exposures to ozone and ozone-derived SOA.

  8. Seaweed biofilters as regulators of water quality in integrated fish-seaweed culture units

    Microsoft Academic Search

    Amir Neori; Michael D. Krom; Steve P. Ellner; Claude E. Boyd; Dan Popper; Ruth Rabinovitch; Patrick J. Davison; Orit Dvir; Daniel Zuber; Michal Ucko; Dror Angel; Hillel Gordin

    1996-01-01

    The water-quality characteristics of a new system for the integrated culture of fish (Sparus aurata L.) and seaweed (Ulva lactuca L.) were examined. Seawater was recirculated between intensive fishponds and seaweed ponds. The seaweed removed most of the ammonia excreted by the fish and oxygenated the water. A model consisting of several tanks and a pilot consisting of two 100-m3,

  9. Design data brochure: Solar hot water system

    NASA Technical Reports Server (NTRS)

    1978-01-01

    A design calculation is detailed for a single-family residence housing a family of four in a nonspecific geographical area. The solar water heater system is designed to provide 80 gallons of 140 F hot water per day.

  10. Mining Gold from your Cooling Water System

    E-print Network

    Mendez, T.

    Mining Gold from your Cooling Water System Tino Mendez Director Energy Engineering The Benham Companies, LLC Oklahoma City, Oklahoma ABSTRACT You may be missing on a fabulous opportunity to save on operating costs in your cooling water...

  11. Rate Setting for Small Water Systems 

    E-print Network

    Dozier, Monty; Theodori, Gene L.; Jensen, Ricard

    2007-03-28

    Knowing how to set the proper rate for water service is a challenge for small water systems. They must generate enough revenue to remain solvent, but offer affordable service. This publication describes the various types of rates and explains...

  12. Cost analysis of water recovery systems

    NASA Technical Reports Server (NTRS)

    Yakut, M. M.

    1972-01-01

    Cost and performance data from Gemini, Skylab, and other aerospace and biotechnology programs were analyzed to identify major cost elements required to establish cost estimating relationships for advanced life support subsystems for long range planning in support of earth orbital programs. Cost analysis are presented for five leading water reclamation systems; (1) RITE waste management-water system;(2) reverse osmosis system;(3) multifiltration system;(4) vapor compression system; and(5) closed air evaporation system with electrolytic pretreatment.

  13. Effect of recirculation and initial concentration of microorganisms on the disinfection kinetics of Escherichia coli

    Microsoft Academic Search

    J. J. Vélez-Colmenares; A. Acevedo; E. Nebot

    2011-01-01

    Disinfection studies with two pure strains of Escherichia coli ATCC 11229 and ATCC 15597 and real municipal wastewater were carried out at laboratory scale with a 10W low pressure ultraviolet lamp in an ultraviolet (UV) disinfection system with recirculation of the liquid. A double first order kinetic model was established to fit the ultraviolet disinfection curves for the two microorganisms.

  14. Monitoring of Leachate Recirculation in a Bioreactor Using Electrical Resistivity

    Microsoft Academic Search

    S. Grellier; N. Bureau; H. Robain; A. Tabbagh; C. Camerlynck; R. Guerin

    2004-01-01

    The bioreactor is a concept of waste landfill management consisting in speeding up the biodegradation by optimizing the moisture content through leachate recirculation. Electrical resistivity tomography (ERT) is carried out with fast resistivity-meter (Syscal Pro, IRIS Instruments, developed in the framework of the research project CERBERE 01V0665-69, funded by the French Research Ministry) to monitor leachate recirculation. During a recirculation

  15. Water film thickness in the clay-water system

    Microsoft Academic Search

    Hiroshi Makihara

    1999-01-01

    The permeable press experiment was performed for aqueous clay mineral systems to understand the relationship between the water film thickness and the applied permeable pressure. Water film thickness between particles was calculated from the particle size and the linear drying shrinkage of pressed bodies. The permeable press experimental results were compared to the calculated total interaction pressures between particles using

  16. ICS solar systems with two water tanks

    Microsoft Academic Search

    Y. Tripanagnostopoulos; M. Souliotis

    2006-01-01

    Integrated collector storage (ICS) systems are compact solar water heaters, simple in construction, installation and operation. They are cheaper than flat plate thermosiphonic units, but their higher thermal losses make them suitable mainly for application in locations with favourable weather conditions. Aiming to the achievement of low system height and satisfactory water temperature stratification, new types of ICS systems with

  17. INDUSTRIAL WASTEWATER RECIRCULATION SYSTEM: PRELIMINARY ENGINEERING

    EPA Science Inventory

    The report details the preliminary engineering work done at Owens-Corning's (O-C's) Anderson, South Carolina, fibrous glass plant. The purpose of the work was to test, on a pilot plant scale, various technologies to be used to clean up industrial wastewater for a closed-loop syst...

  18. The molecular adsorbent recirculating system (MARS®)

    Microsoft Academic Search

    Martin Boyle; I BALDWIN

    2005-01-01

    The consequences of liver failure include hepatic encephalopathy, haemodynamic instability, cerebral oedema, renal failure, susceptibility to infection, coagulapathy and metabolic derangement. Liver transplantation is the only established treatment for patients who do not respond to medical management. However, the supply of organs for transplant is limited. Artificial liver support therapies are available to support patients in acute liver failure to

  19. Space shuttle galley water system test program

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A water system for food rehydration was tested to determine the requirements for a space shuttle gallery flight system. A new food package concept had been previously developed in which water was introduced into the sealed package by means of a needle and septum. The needle configuration was developed and the flow characteristics measured. The interface between the food package and the water system, oven, and food tray was determined.

  20. Exhaust gas recirculation in a homogeneous charge compression ignition engine

    DOEpatents

    Duffy, Kevin P. (Metamora, IL); Kieser, Andrew J. (Morton, IL); Rodman, Anthony (Chillicothe, IL); Liechty, Michael P. (Chillicothe, IL); Hergart, Carl-Anders (Peoria, IL); Hardy, William L. (Peoria, IL)

    2008-05-27

    A homogeneous charge compression ignition engine operates by injecting liquid fuel directly in a combustion chamber, and mixing the fuel with recirculated exhaust and fresh air through an auto ignition condition of the fuel. The engine includes at least one turbocharger for extracting energy from the engine exhaust and using that energy to boost intake pressure of recirculated exhaust gas and fresh air. Elevated proportions of exhaust gas recirculated to the engine are attained by throttling the fresh air inlet supply. These elevated exhaust gas recirculation rates allow the HCCI engine to be operated at higher speeds and loads rendering the HCCI engine a more viable alternative to a conventional diesel engine.

  1. Nitrification kinetics of biofilm as affected by water quality factors

    Microsoft Academic Search

    Shulin Chen; Jian Ling; Jean-Paul Blancheton

    2006-01-01

    Various types of fixed film biofilters have been used in recirculating aquaculture systems under different water quality and operating conditions. The effectiveness of the nitrification process can be evaluated by nitrification kinetics. Nitrification in the bacterial film of the biofilter involves physical, chemical and biological processes that are governed by a variety of parameters such as substrate and dissolved oxygen

  2. STANDARDIZED COST FOR WATER SUPPLY DISTRIBUTION SYSTEMS

    EPA Science Inventory

    There are a significant number of water supply distribution systems in the United States that are deteriorating, resulting in a potential threat to the future quality of drinking water. orrective measures will directly influence the cost of providing water. t would be useful to h...

  3. Grey Water Treatment Systems: A Review

    Microsoft Academic Search

    Lina Abu Ghunmi; Grietje Zeeman; Manar Fayyad; Jules B. van Lier

    2011-01-01

    This review aims to discern a treatment for grey water by examining grey water characteristics, reuse standards, technology performance and costs. The review reveals that the systems for treating grey water, whatever its quality, should consist of processes that are able to trap pollutants with a small particle size and convert organic matter to mineralized compounds. For efficient, simple and

  4. Recirculating Linear Accelerators for Future Muon Facilities

    SciTech Connect

    S.A. Bogacz, K.B.Beard, R.P. Johnson

    2010-05-01

    Neutrino Factories (NF) and Muon Colliders (MC) require rapid acceleration of short-lived muons to multi-GeV and TeV energies. A Recirculating Linear Accelerator (RLA) that uses superconducting RF structures can provide exceptionally fast and economical acceleration to the extent that the focusing range of the RLA quadrupoles allows each muon to pass several times through each high-gradient cavity. A new concept of rapidly changing the strength of the RLA focusing quadrupoles as the muons gain energy is being developed to increase the number of passes that each muon will make in the RF cavities, leading to greater cost effectiveness.

  5. Evaluation of the yields from the radiolysis of water in boiling water reactors by neutron and gamma radiation

    Microsoft Academic Search

    E. Ibe; S. Uchida

    1983-01-01

    A computer program package AQUARY has been developed for quantitative evaluation of concentration distributions of the radiolytic species in overall boiling water reactor primary systems. The hydrogen peroxide decomposition rate, the gas release coefficient and the accumulation of products through recirculation of the coolant were taken into consideration. The following relations were found: 1. Hydrogen and hydrogen peroxide concentrations in

  6. Service Water System Inspection Locator (SWSIL)

    SciTech Connect

    Pytel, M.L.; Tang, S.S.; Carney, C.E.; Licina, G.J. (Structural Integrity Associates, Inc., San Jose, CA (United States))

    1993-04-01

    Inspection and maintenance of a service water system is a key to reliable system operation. As emphasized by NRC Generic Letter 89-13, service water system reliability in nuclear plants must by assured since the SWS may support safety related equipment The diversity of design, water chemistry, and operating regimens, coupled with the tremendous size of these systems (literally miles of piping and hundreds of heat exchangers) makes the selection of locations to be inspected a difficult chore. In cooperation with the Electric Power Research Institute (EPRI) and the New York Power Authority (NYPA), a Service Water System Inspection Locator (SWSIL) has been developed to explore the feasibility of using an expert system to evaluate the corrosion susceptibility of the thousands of locations and components associated with nuclear service water systems (SWS). Such an expert system provides utilities with a method for planning and prioritizing inspections. SWSIL, Version 1.0, has been applied to the emergency diesel generator service water cooling loop of the emergency service water (ESW) system of the James A. FitzPatrick plant. The feasibility demonstration described in this report provided a framework for applying SWSIL to a system of any size. The demonstration also showed that refinement of the plant data input interface and flow modeling are required. Applicability of SWSIL in its current configuration to large systems is limited and awaits these improvements.

  7. System for removal of arsenic from water

    DOEpatents

    Moore, Robert C.; Anderson, D. Richard

    2004-11-23

    Systems for removing arsenic from water by addition of inexpensive and commonly available magnesium oxide, magnesium hydroxide, calcium oxide, or calcium hydroxide to the water. The hydroxide has a strong chemical affinity for arsenic and rapidly adsorbs arsenic, even in the presence of carbonate in the water. Simple and commercially available mechanical systems for removal of magnesium hydroxide particles with adsorbed arsenic from drinking water can be used, including filtration, dissolved air flotation, vortex separation, or centrifugal separation. A system for continuous removal of arsenic from water is provided. Also provided is a system for concentrating arsenic in a water sample to facilitate quantification of arsenic, by means of magnesium or calcium hydroxide adsorption.

  8. Prototype solar domestic hot water systems

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Construction of a double wall heat exchanger using soft copper tube coiled around a hot water storage tank was completed and preliminary tests were conducted. Solar transport water to tank potable water heat exchange tests were performed with a specially constructed test stand. Work was done to improve the component hardware and system design for the solar water heater. The installation of both a direct feed system and a double wall heat exchanger system provided experience and site data to enable informative decisions to be made as the solar market expands into areas where freeze protection is required.

  9. An Ice Storage System using Supercooled Water

    NASA Astrophysics Data System (ADS)

    Moriya, Mitsuru; Tanino, Masayuki; Kikuchi, Sakae; Hayashi, Toshio; Okonogi, Tokio; Kozawa, Yoshiyuki

    An ice storage system using supercooled water has been developed. In this system, only water is circulated and slurry-ice is stored in tanks. Since one of the critical components of the system is the supercooing heat exchanger, the first step in component development consisted in verification of stable conditions for supercooling water control by basic and integrated experiments. The results of these experiments yielded designcriteria concerning the degree of wall supercooling and the inlet water temperatures (i.e.,conditions for absence of ice nuclei). In addition, realistic operating techniques for supercooling heat exchangers with redundancy have been demonstrated by the field experiment.

  10. Cost analysis of water recovery systems

    NASA Technical Reports Server (NTRS)

    Yakut, M. M.

    1973-01-01

    A methodology was developed to predict the relevant contributions of the more intangible cost elements encountered in the development of flight-qualified hardware based on an extrapolation of past hardware development experience. Major items of costs within water recovery systems were identified and related to physical and/or performance criteria. Cost and performance data from Gemini, Skylab, and other aerospace and biotechnology programs were analyzed to identify major cost elements required to establish cost estimating relationships for advanced water recovery systems. The results of the study are expected to assist NASA in long-range planning and allocation of resources in a cost effective manner in support of earth orbital programs. This report deals with the cost analysis of the five leading water reclamation systems, namely: (1) RITE waste management-water system, (2) reverse osmosis system, (3) multifiltration system, (4) vapor compression system, and (5) closed air evaporation system with electrolytic pretreatment.

  11. Information Sources for Small Water Systems 

    E-print Network

    Dozier, Monty; Theodori, Gene L.; Jensen, Ricard

    2007-02-19

    -Assessment Guide for Small Drinking Water Systems Serving Populations between 3,300 and 10,000. A copy can be downloaded from the Texas Commission of Environmental Quality (TCEQ) at the following website: http://www. tceq... response topics. Materials can be downloaded directly from http://texashelp.tamu.edu. The National EDEN website is http://www.eden.lsu.edu/. Southern Region Water Quality Information System This website provides abundant water quality information...

  12. Liquid Assets: A Water System

    NSDL National Science Digital Library

    WPSU

    2008-11-20

    This segment from a WPSU documentary Liquid Assets succinctly explains how water in New York journeys from its source to our faucets. Although water flows under our feet everyday, we are blissfully unaware of this service and take it for granted.

  13. Economic viability of photovoltaic water pumping systems

    Microsoft Academic Search

    I. Odeh; Y. G. Yohanis; Brian Norton

    2006-01-01

    A comparison of the economic viability of photovoltaic and diesel water pumping systems is presented for system sizes in the range 2.8kWp to 15kWp. Actual performance data from installed systems are employed for the base case. Sensitivity analysis is carried out to generalize results for other locations and conditions. The effect of system oversizing due to mismatch of water supply

  14. Recirculating Planar Magnetron Modeling and Experiments

    NASA Astrophysics Data System (ADS)

    Franzi, Matthew; Gilgenbach, Ronald; Hoff, Brad; French, Dave; Lau, Y. Y.

    2011-10-01

    We present simulations and initial experimental results of a new class of crossed field device: Recirculating Planar Magnetrons (RPM). Two geometries of RPM are being explored: 1) Dual planar-magnetrons connected by a recirculating section with axial magnetic field and transverse electric field, and 2) Planar cathode and anode-cavity rings with radial magnetic field and axial electric field. These RPMs have numerous advantages for high power microwave generation by virtue of larger area cathodes and anodes. The axial B-field RPM can be configured in either the conventional or inverted (faster startup) configuration. Two and three-dimensional EM PIC simulations show rapid electron spoke formation and microwave oscillation in pi-mode. Smoothbore prototype axial-B RPM experiments are underway using the MELBA accelerator at parameters of -300 kV, 1-20 kA and pulselengths of 0.5-1 microsecond. Implementation and operation of the first RPM slow wave structure, operating at 1GHz, will be discussed. Research supported by AFOSR, AFRL, L-3 Communications, and Northrop Grumman. Done...processed 1830 records...17:52:57 Beginning APS data extraction...17:52:57

  15. High speed exhaust gas recirculation valve

    DOEpatents

    Fensom, Rod (Peterborough, GB); Kidder, David J. (Peterborough, GB)

    2005-01-18

    In order to minimize pollutants such as Nox, internal combustion engines typically include an exhaust gas recirculation (EGR) valve that can be used to redirect a portion of exhaust gases to an intake conduit, such as an intake manifold, so that the redirected exhaust gases will be recycled. It is desirable to have an EGR valve with fast-acting capabilities, and it is also desirable to have the EGR valve take up as little space as possible. An exhaust gas recirculation valve is provided that includes an exhaust passage tube, a valve element pivotally mounted within the exhaust passage tube, a linear actuator; and a gear train. The gear train includes a rack gear operatively connected to the linear actuator, and at least one rotatable gear meshing with the rack gear and operatively connected to the valve element to cause rotation of the valve element upon actuation of the linear actuator. The apparatus provides a highly compact package having a high-speed valve actuation capability.

  16. Reliable water supply system design under uncertainty

    Microsoft Academic Search

    G. Chung; K. Lansey; Güzin Bayraksan

    2009-01-01

    Given the natural variability and uncertainties in long-term predictions, reliability is a critical design factor for water supply systems. However, the large scale of the problem and the correlated nature of the involved uncertainties result in models that are often intractable. In this paper, we consider a municipal water supply system over a 15-year planning period with initial infrastructure and

  17. Submersible purification system for radioactive water

    SciTech Connect

    Abbot, M.L.; Lewis, D.R.

    1989-05-09

    A portable, submersible water purification system for use in a pool of water containing radioactive contamination includes a prefilter for filtering particulates from the water. A resin bed is then provided for removal of remaining dissolved, particulate, organic, and colloidal impurities from the prefiltered water. A sterilizer then sterilizes the water. The prefilter and resin bed are suitably contained and are submerged in the pool. The sterilizer is water tight and located at the surface of the pool. The water is circulated from the pool through the prefilter, resin bed, and sterilizer by suitable pump or the like. In the preferred embodiment, the resin bed is contained within a tank which stands on the bottom of the pool and to which a base mounting the prefilter and pump is attached. An inlet for the pump is provided adjacent the bottom of the pool, while the sterilizer and outlet for the system is located adjacent the top of the pool.

  18. [Processing conditions of recirculated MBR for wastewater treatment].

    PubMed

    Lü, Hong; Xu, Youyi; Zhu, Baoku; Xu, Zhikang; Xie, Boming

    2003-05-01

    In this paper, wastewater was treated with Recirculated Membrane Bio-Reactor (RMBR) and effluent quality became stable after four days running continuously. Critical membrane flux was increased with increasing crossflow velocity between 0.9-1.9 m/s. Under crossflow velocity of 1.9 m/s, critical membrane flux was enhanced from 72 L/(m2.h) to 76 L/(m2.h) or 81 L/(m2.h) respectively when powdered activated carbon (PAC) or both PAC and alum were added to the system. Between 22 degrees C-30 degrees C, the flux was elevated 1.9% per 1 degree C increased. Fouling materials were removed efficiently through cleaning physically or/and chemically with flux recovery of 47%-94%. PMID:12916204

  19. Continuous Commissioning of a Central Chilled Water & Hot Water System

    E-print Network

    Deng, S.; Turner, W. D.; Batten, T.; Liu, M.

    2000-01-01

    chilled water and hot water flow rates. This will save pumping energy and improve chillerhoiler e ficienc y. I. INTRODUCTION Continuous Commissioning (CC) began as part M.Liu,Ph.D.,P.E. Associate Professor Architecture Engineering Dept. University...: (979) 862-2457 Email: tbatten@esl.tarnu.edu of the Texas LoanSTAR program at the Energy Systems Laboratory (ESL) at Texas A&M University (Claridge, 1994; Liu, 1994). Continuous Commissioning (CC) emerged from a program of implementing operation...

  20. Water turbine system and method of operation

    DOEpatents

    Costin, Daniel P.

    2010-06-15

    A system for providing electrical power from a current turbine is provided. The system includes a floatation device and a mooring. A water turbine structure is provided having an upper and lower portion wherein the lower portion includes a water fillable chamber. A plurality of cables are used to couple the system where a first cable couples the water turbine to the mooring and a second cable couples the floatation device to the first cable. The system is arranged to allow the turbine structure to be deployed and retrieved for service, repair, maintenance and redeployment.

  1. Water turbine system and method of operation

    DOEpatents

    Costin, Daniel P. (Montpelier, VT)

    2011-05-10

    A system for providing electrical power from a current turbine is provided. The system includes a floatation device and a mooring. A water turbine structure is provided having an upper and lower portion wherein the lower portion includes a water fillable chamber. A plurality of cables are used to couple the system where a first cable couples the water turbine to the mooring and a second cable couples the floatation device to the first cable. The system is arranged to allow the turbine structure to be deployed and retrieved for service, repair, maintenance and redeployment.

  2. Water turbine system and method of operation

    DOEpatents

    Costin, Daniel P. (Montpelier, VT)

    2009-02-10

    A system for providing electrical power from a current turbine is provided. The system includes a floatation device and a mooring. A water turbine structure is provided having an upper and lower portion wherein the lower portion includes a water fillable chamber. A plurality of cables are used to couple the system where a first cable couples the water turbine to the mooring and a second cable couples the floatation device to the first cable. The system is arranged to allow the turbine structure to be deployed and retrieved for service, repair, maintenance and redeployment.

  3. Partitioning sources of recharge in environments with groundwater recirculation using carbon-14 and CFC-12

    NASA Astrophysics Data System (ADS)

    Bourke, Sarah A.; Cook, Peter G.; Dogramaci, Shawan; Kipfer, Rolf

    2015-06-01

    Groundwater recirculation occurs when groundwater is pumped from an aquifer onto the land surface, and a portion of that water subsequently infiltrates back to the aquifer. In environments where groundwater is recirculated, differentiation between various sources of recharge (e.g. natural rainfall recharge vs. recirculated water) can be difficult. Groundwater age indicators, in particular transient trace gases, are likely to be more sensitive tracers of recharge than stable isotopes or chloride in this setting. This is because, unlike stable isotopes or chloride, they undergo a process of equilibration with the atmosphere, and historical atmospheric concentrations are known. In this paper, groundwater age indicators (14C and CFC-12) were used as tracers of recharge by surplus mine water that is discharged to streams. Ternary mixing ratios were calculated based on 14C and CFC-12 concentrations measured along three transects of piezometers and monitoring wells perpendicular to the creeks, and from dewatering wells. Uncertainty in calculated mixing ratios was estimated using a Monte Carlo approach. Ternary mixing ratios in dewatering wells suggest that recharge by mine water accounted for between 10% and 87% of water currently abstracted by dewatering wells. The calculated mixing ratios suggest that recharge by mine water extends to a distance of more than 550 m from the creeks. These results are supported by seepage flux estimates based on the water and chloride balance along the creeks, which suggest that 85-90% of mine water discharged to the creeks recharges the aquifer and recharge by mine water extends between 110 and 730 m from the creeks. Mixing calculations based on gaseous groundwater age indicators could also be used to partition recharge associated with agricultural irrigation or artificial wetland supplementation.

  4. 'GIARDIA' DETECTION IN WATER SYSTEMS

    EPA Science Inventory

    A method has been developed combining immunofluorescence and phase-contrast to microscopically locate and identify Giardia cysts among particulates filtered from water samples. Selective staining of cysts with anti-Giardia antiserum and a fluorochrom enhances the contrast between...

  5. Spacesuit Water Membrane Evaporator; An Enhanced Evaporative Cooling System for the Advanced Extravehicular Mobility Unit Portable Life Support System

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Makinen, Janice V.; Miller, Sean; Campbell, Colin; Lynch, Bill; Vogel, Matt; Craft, Jesse; Wilkes, Robert; Kuehnel, Eric

    2014-01-01

    Development of the Advanced Extravehicular Mobility Unit (AEMU) portable life support subsystem (PLSS) is currently under way at NASA Johnson Space Center. The AEMU PLSS features a new evaporative cooling system, the Generation 4 Spacesuit Water Membrane Evaporator (Gen4 SWME). The SWME offers several advantages when compared with prior crewmember cooling technologies, including the ability to reject heat at increased atmospheric pressures, reduced loop infrastructure, and higher tolerance to fouling. Like its predecessors, Gen4 SWME provides nominal crew member and electronics cooling by flowing water through porous hollow fibers. Water vapor escapes through the hollow fiber pores, thereby cooling the liquid water that remains inside of the fibers. This cooled water is then recirculated to remove heat from the crew member and PLSS electronics. Test results from the backup cooling system which is based on a similar design and the subject of a companion paper, suggested that further volume reductions could be achieved through fiber density optimization. Testing was performed with four fiber bundle configurations ranging from 35,850 fibers to 41,180 fibers. The optimal configuration reduced the Gen4 SWME envelope volume by 15% from that of Gen3 while dramatically increasing the performance margin of the system. A rectangular block design was chosen over the Gen3 cylindrical design, for packaging configurations within the AEMU PLSS envelope. Several important innovations were made in the redesign of the backpressure valve which is used to control evaporation. A twin-port pivot concept was selected from among three low profile valve designs for superior robustness, control and packaging. The backpressure valve motor, the thermal control valve, delta pressure sensors and temperature sensors were incorporated into the manifold endcaps, also for packaging considerations. Flight-like materials including a titanium housing were used for all components. Performance testing of the Gen4 SWME is underway.

  6. An expert system for water quality modelling

    Microsoft Academic Search

    W. G. Booty; D. C. L. Lam; A. G. Bobba; I. Wong; D. Kay; J. P. Kerby; G. S. Bowen

    1992-01-01

    The RAISON-micro (Regional Analysis by Intelligent System ON a micro-computer) expert system is being used to predict the effects of mine effluents on receiving waters in Ontario. The potential of this system to assist regulatory agencies and mining industries to define more acceptable effluent limits was shown in an initial study. This system has been further developed so that the

  7. Data processing for water monitoring system

    NASA Technical Reports Server (NTRS)

    Monford, L.; Linton, A. T.

    1978-01-01

    Water monitoring data acquisition system is structured about central computer that controls sampling and sensor operation, and analyzes and displays data in real time. Unit is essentially separated into two systems: computer system, and hard wire backup system which may function separately or with computer.

  8. Ignition timing control system for an automotive engine

    Microsoft Academic Search

    K. Ohtaki; K. Hara

    1986-01-01

    This patent describes an ignition timing control system for an automotive engine with an exhaust gas recirculation system having an exhuast gas recirculation passage and an exhuast gas recirculation valve operated by a vacuum operated actuator provided in the recirculation passage. The improvement described here consists of: a primary vacuum-advance means responsive to the vacuum at a first vacuum port

  9. 80 FR 34170 - Notice of Intent To Prepare a Recirculated Draft Environmental Impact Report/Supplemental Draft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2015-06-15

    The Bureau of Reclamation and the California Department of Water Resources intend to prepare a partially Recirculated Draft Environmental Impact Report/Supplemental Draft Environmental Impact Statement (RDEIR/SDEIS) on the Draft Bay Delta Conservation Plan and Natural Community Conservation Plan (BDCP, or the Plan). The RDEIR/SDEIS will describe and analyze refinement of the resource area......

  10. Safety Features Comparative Study between Advanced Boiling Water Reactor and Supercritical Water-Cooling Reactor

    Microsoft Academic Search

    Hangding Wang; Tao Zhou; Zhousen Hou

    2011-01-01

    Supercritical water-cooling reactor is one of the advanced nuclear power plants as the fourth generation reactor of internationally recognized. The plant system design is once-through cycle, feed-water flow rate are provided from pressure head by pump through the reactor core became steam, and directly into the turbine. There is not a recirculation loop in this cycle, this is the the

  11. Wash water waste pretreatment system

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Investigations were completed on wash waters based on each candidate personal cleansing agent. Evaluations of coagulants, antifoam agents, and the effect of promising antifoams on the chemical precipitation were included. Based on these evaluations two candidate soaps as well as their companion antifoam agents were selected for further work. Operating parameters included the effect of soap concentration, ferric chloride concentration, duration of mixing, and pore size of depth filters on the degree of soap removal. The effect of pressure on water flow through filter cartridges and on the rate of decline of water flow was also investigated. The culmination of the program was the recommendation of a pretreatment concept based on chemical precipitation followed by pressure filtration.

  12. Fouling in cooling water systems

    NASA Astrophysics Data System (ADS)

    1988-11-01

    This Data Item 88024, an addition to the Sub-series on Heat Transfer, considers scaling, corrosion, biofouling and particulate deposition and discusses the variables of importance for each. Advice is given on the design and subsequent operational management of a plant to minimize fouling. The importance of the water source, and hence its composition, is emphasised. Test equipment for assessing fouling is described. A table of heat transfer fouling resistances, showing their depemdence on temperature, water velocity, material and water treatment applied, will be of particular value. Various means of fouling control are considered, using chemicals and biocides as appropriate. The properties of biocides currently used in industrial applications are discussed. On-line mechanical cleaning methods are also considered.

  13. The potable water system in Skylab

    NASA Technical Reports Server (NTRS)

    Sauer, R. L.; Westover, J. B.

    1974-01-01

    Description of the medical requirements, development, system operation, and in-flight performance of the Skylab potable water system. Emphasized is the description of the unique features involving new space-flight concepts, procedures, and design incorporated in Skylab. The water supplied to the three Skylab missions was preloaded in stainless-steel tanks. These tanks were fitted with positive expulsion stainless-steel bellows. In-flight iodination of the water, for bacterial control, was accomplished as required. An in-flight bactericide monitor was used periodically to determine the level of bactericide in the water. Prior to the delivery of the water to the crewmen for consumption, the water was passed through a cation exchange resin for metallic ion removal and then heated for food reconstitution or chilled for drinking.

  14. Robot design for leak detection in water-pipe systems

    E-print Network

    Choi, Changrak

    2012-01-01

    Leaks are major problem that occur in the water pipelines all around the world. Several reports indicate loss of around 20 to 30 percent of water in the distribution of water through water pipe systems. Such loss of water ...

  15. Traffic and proliferative responses of recirculating lymphocytes in fetal calves.

    PubMed Central

    Hein, W R; Shelton, J N; Simpson-Morgan, M W; Morris, B

    1988-01-01

    The thoracic duct or efferent prescapular duct was cannulated in four fetal calves aged 121-259 days post-conception. The duration of lymph flow ranged from 2 to 20 days and the mean flow rates sustained over these collection periods varied from 5.4 to 48.8 ml/hr. Lymphocyte output ranged from 4.4 x 10(6) cells/hr in thoracic duct lymph from a 121-day fetus to 3.9 x 10(8) cells/hr in efferent prescapular lymph from a 259-day fetus. The circulating lymphocyte pool in fetal calves of about 120 and 190 days gestational age was calculated to contain, respectively, 4 x 10(8) cells and 2 x 10(10) cells. The proportion of lymphocytes bearing surface immunoglobulin detected in fetal lymph ranged from 2.1% to 8.7%. Recirculating lymphocytes from fetal calves produced strong proliferative responses when stimulated by T-cell mitogens but responded poorly to B-cell mitogens. Fetal lymphocytes also responded to stimulation by allogeneic cells and stimulated other cells to proliferate during mixed lymphocyte culture. When stimulated with Con A, fetal lymphocytes secreted IL-2 to a degree that was indistinguishable from the secretory behaviour of lymphocytes from adult animals. The results presented in this paper show that chronic lymphatic fistulae can be established successfully in fetal calves to give access to recirculating lymphocytes. This provides a new experimental approach for studying the development of the bovine immune system. PMID:2971606

  16. Hydrogeological Factors for Sustainable Urban Water Systems

    Microsoft Academic Search

    MATTHIAS EISWIRTH

    \\u000a Abstract\\u000a \\u000a Urban transport systems and the provision of water have been identified as the factors most critical in determining the future\\u000a of cities in this new century. The effectiveness of conventional technical urban water concepts has reached a limit, and the\\u000a sustainability of such practice is in question. There are a number of different types of key urban water indicators

  17. Brillouin Flow in Recirculating Planar Magnetron

    NASA Astrophysics Data System (ADS)

    Simon, D. H.; Lau, Y. Y.; Franzi, M.; Greening, G.; Gilgenbach, R. M.

    2013-10-01

    We examine the Brillouin flow in the conventional magnetron, inverted magnetron, and planar magnetron, with respect to the equilibrium, stability, and operating conditions. This renewed interest was prompted by our recent invention of the recirculating planar magnetron (RPM), where rapid start up utilizes the negative mass instability in the inverted magnetron configuration. Given that Brillouin flow is the most likely state in a crossed-field gap, and that various embodiments of the RPM consist of the conventional, inverted, and planar magnetron, it is necessary to study equilibrium, stability, and operating conditions at the same footing. To study startup, we solve the eigenvalue problem that governs the stability of Brillouin flow, including the effects of the resonant cavities that form the slow wave structures. We examine the Brillouin flow in the conventional magnetron, inverted magnetron, and planar magnetron, with respect to the equilibrium, stability, and operating conditions. This renewed interest was prompted by our recent invention of the recirculating planar magnetron (RPM), where rapid start up utilizes the negative mass instability in the inverted magnetron configuration. Given that Brillouin flow is the most likely state in a crossed-field gap, and that various embodiments of the RPM consist of the conventional, inverted, and planar magnetron, it is necessary to study equilibrium, stability, and operating conditions at the same footing. To study startup, we solve the eigenvalue problem that governs the stability of Brillouin flow, including the effects of the resonant cavities that form the slow wave structures. Work supported by AFOSR (grant #: FA9550-10-1-0104), and L-3 Communications Electron Devices.

  18. Recirculating planar magnetrons: simulations and experiment

    SciTech Connect

    Franzi, Matthew; Gilgenbach, Ronald; French, David; Lau, Y.Y.; Simon, David [Plasma, Pulsed Power and Microwave Lab., Nuclear Engineering and Radiological Sciences Department, University of Michigan, Ann Arbor, Ml (United States); Hoff, Brad [Air Force Research Lab., Kirtland AFB, NM (United States); Luginsland, John W. [Air Force Office of Scientific Research, Arlington, VA (United States)

    2011-07-01

    The Recirculating Planar Magnetron (RPM) is a novel crossed-field device whose geometry is expected to reduce thermal load, enhance current yield as well as ease the geometric limitations in scaling to high RF frequencies as compared to the conventional cylindrical magnetrons. The RPM has two different adaptations: A. Axial B field and radial E field; B. Radial B field and axial E field. The preliminary configuration (A) to be used in experiments at the University of Michigan consists of two parallel planar sections which join on either end by cylindrical regions to form a concentric extruded ellipse. Similar to conventional magnetrons, a voltage across the AK gap in conjunction with an axial magnetic field provides the electrons with an ExB drift. The device is named RPM because the drifting electrons recirculate from one planar region to the other. The drifting electrons interact with the resonantly tuned slow wave structure on the anode causing spoke formation. These electron spokes drive a RF electric field in the cavities from which RF power may be extracted to Waveguides. The RPM may be designed in either a conventional configuration with the anode on the outside, for simplified extraction, or as an inverted magnetron with the anode at the inner conductor, for fast start-up. Currently, experiments at the Pulsed Power and Microwave Laboratory at the University of Michigan are in the setup and design phase. A conventional RPM with planar cavities is to be installed on the Michigan Electron Long Beam Accelerator (MELBA) and is anticipated to operate at -200kV, 0.2T with a beam current of 1-10 kA at 1GHz. The conventional RPM consists of 12 identical planar cavities, 6 on each planar side, with simulated quality factor of 20.

  19. Investigation of groundwater recirculation for the removal of RDX from the Pantex Plant perched aquifer

    SciTech Connect

    Woods, A.L. [ed.; Barnes, D.L. [Amarillo National Resource Center for Plutonium, TX (United States); Boles, K.M.; Charbeneau, R.J. [Univ. of Texas, Austin, TX (United States); Black, S.; Rainwater, K. [Texas Tech Univ., Lubbock, TX (United States). Water Resources Center

    1998-07-01

    The Pantex Plant near Amarillo, Texas, is a US Department of Energy (DOE) facility that has been in operation since 1942. Past and present operations at Pantex include the creation of chemical high explosives components for nuclear weapons and assembly and disassembly of nuclear weapons. The Pantex Plant is underlain by the Ogallala aquifer, which in this area, consists of the main water-bearing unit and a perched water zone. These are separated by a fine-grained zone of low permeability. Multiple contaminant plumes containing high explosive (HE) compounds have been detected in the perched aquifer beneath the plant. The occurrence of these contaminants is the result of past waste disposal practices at the facility. RDX is an HE compound, which has been detected in the groundwater of the perched aquifer at significant concentrations. A pilot-scale, dual-phase extraction treatment system has been installed at one location at the plant, east of Zone 12, to test the effectiveness of such a system on the removal of these contaminants from the subsurface. A tracer test using a conservative tracer, bromide (Br), was conducted at the treatment site in 1996. In addition to the bromide, RDX and water elevations in the aquifer were monitored. Using data from the tracer test and other relevant data from the investigations at Pantex, flow and contaminant transport in the perched aquifer were simulated with groundwater models. The flow was modeled using MODFLOW and the transport of contaminants in the aqueous phase was modeled using MT3D. Modeling the perched aquifer had been conducted to characterize the flow in the perched aquifer; estimate RDX retardation in the perched aquifer; and evaluate the use of groundwater re-circulation to enhance the extraction of RDX from the perched aquifer.

  20. Biofilm accumulation in drinking water distribution systems

    Microsoft Academic Search

    J. C. Block; K. Haudidier; J. L. Paquin; J. Miazga; Y. Levi

    1993-01-01

    In order to classify the relative importance of the parameters governing the accumulation of biofilm in drinking water distribution systems, a study has been carried out, using an industrial pilot plant fed with finished waters, with three main objectives, viz. (i) determination of biofilm density on pipe surfaces (PVC or cement lined cast iron) as a function of the distance

  1. Passive safety injection system using borated water

    SciTech Connect

    Conway, Lawrence E. (Allegheny, PA); Schulz, Terry L. (Westmoreland, PA)

    1993-01-01

    A passive safety injection system relies on differences in water density to induce natural circulatory flow patterns which help maintain prescribed concentrations of boric acid in borated water, and prevents boron from accumulating in the reactor vessel and possibly preventing heat transfer.

  2. OPTIMIZATION OF STATE WATER QUALITY MONITORING SYSTEMS

    EPA Science Inventory

    The water quality monitoring activities required of the States under the Federal Water Pollution Control Act Amendments (PL92-500) will require resources well beyond what is likely to be available, if current systems structures and operating procedures are followed. This paper de...

  3. Recirculating induction accelerators for inertial fusion: Prospects and status

    SciTech Connect

    Friedman, A.; Barnard, J.J.; Cable, M.D. [and others

    1995-09-03

    The US is developing the physics and technology of induction accelerators for heavy-ion beam-driven inertial fusion. The recirculating induction accelerator repeatedly passes beams through the same set of accelerating and focusing elements, thereby reducing both the length and gradient of the accelerator structure. This promises an attractive driver cost, if the technical challenges associated with recirculation can be met. Point designs for recirculator drivers were developed in a multi-year study by LLNL, LBNL, and FM Technologies, and that work is briefly reviewed here. To validate major elements of the recirculator concept, we are developing a small (4-5-m diameter) prototype recirculator which will accelerate a space-charge-dominated beam of K{sup +} ions through 15 laps, from 80 to 320 keV and from 2 to 8 mA. Transverse beam confinement is effected via permanent-magnet quadrupoles; bending is via electric dipoles. This ``Small Recirculator`` is being developed in a build-and-test sequence of experiments. An injector, matching section, and linear magnetic channel using seven half-lattice periods of permanent-magnet quadrupole lenses are operational. A prototype recirculator half-lattice period is being fabricated. This paper outlines the research program, and presents initial experimental results.

  4. Exhaust gas recirculation method for internal combustion engines

    SciTech Connect

    Kawanabe, T.; Kimura, K.; Asakura, M.; Shiina, T.

    1988-07-19

    This patent describes a method of controlling exhaust gas recirculation in an internal combustion engine having an exhaust passage, an intake passage, an exhaust gas recirculating passage communicating the exhaust passage with the intake passage, and exhaust gas recirculating valve; and a transmission having a shift lever. The valve opening of the exhaust gas recirculating valve is controlled in response to operating conditions of the engine so as to regulate the amount of exhaust gas recirculation to values appropriate to the operating conditions of the engine. The method comprising the steps of (1) determining whether or not the engine is in at least one of a predetermined accelerating condition and a predetermined decelerating condition; (2) varying the valve opening of the exhaust gas recirculating valve by a predetermined value when the engine is determined to be in at least one of the predetermined accelerating condition and the predetermined decelerating condition; (3) detecting a position of the shift lever of the transmission; and (4) correcting the predetermined value in accordance with the detected position of the shift lever so as to increase the valve opening of the exhaust gas recirculating valve as the shift lever of the transmission is set to a higher speed position.

  5. Direct determination of blood recirculation rate in hemodialysis by a conductivity method.

    PubMed

    Bosc, J Y; LeBlanc, M; Garred, L J; Marc, J M; Foret, M; Babinet, F; Tetta, C; Canaud, B

    1998-01-01

    Blood recirculation is one of the key factors of decreasing dialysis efficiency. Determination of recirculation rate (R) is necessary to optimize effective dialysis delivery and to monitor vascular access function. R can be directly measured by a conductivity method in paired filtration dialysis (PFD), a double-compartment hemodiafiltration system that permits direct access to plasma water via the ultrafiltration stream. Measurement of R, in this system, involves the first of two conductivity sensors integrated in a urea monitor (UMS, BelIco-Sorin, Mirandola, Italy), and two saline injections. The rise in conductivity (deltaC1) induced by a 2.7 ml bolus of hypertonic saline 20% (mg/dl) in the arterial line serves for calibration, and is followed by an equivalent injection into the venous line, giving rise to deltaC2. The ratio deltaC2/deltaC1 equals R. A comparison between R values obtained with this method and with the low-flow technique in 31 chronic dialysis patients during 138 PFD sessions is reported. Mean R+/-SD by the conductivity method was 5.1+/-2.0 and 5.7+/-2.0% after 65 and 155 minutes of PFD (correlation coefficient, r = 0.75), whereas it was 6.4+/-4.9% and 5.5+/-4.6% after 30 sec of low blood pump flow for urea and creatinine markers, respectively (r = 0.35). After 120 sec of low flow, mean R increased to 9.0+/-5.1 and 8.8+/-4.6% for urea and creatinine, respectively (r = 0.45). Considerable discrepancies were found in R values measured simultaneously with the two blood markers. Statistically significant differences were found between the two measurement modalities (blood-side and conductivity); the correlation coefficients (r) varied between 0.28 and 0.41. The observed differences in mean R results do not seem considerable from a clinical perspective. The best agreement between blood-side and conductivity R measurements was obtained with Rcreat after 30 sec of low flow. Overall, a wider distribution was found in R values from blood-side determinations, most likely consequent to variability in the dosing method. The conductivity method appears more accurate and simple in assessing total R, and can be readily automated and integrated into the dialysis machine. The authors, therefore, recommend evaluation of R using methods not based on chemical blood concentration values. PMID:9466504

  6. WATER QUALITY EARLY WARNING SYSTEMS FOR SOURCE WATER AND DISTRIBUTION SYSTEM MONITORING

    EPA Science Inventory

    A variety of probes for use in continuous monitoring of water quality exist. They range from single parameter chemical/physical probes to comprehensive screening systems based on whole organism responses. Originally developed for monitoring specific characteristics of water qua...

  7. INTEGRATED WATER TREATMENT SYSTEM PERFORMANCE EVALUATION

    SciTech Connect

    SEXTON RA; MEEUWSEN WE

    2009-03-12

    This document describes the results of an evaluation of the current Integrated Water Treatment System (IWTS) operation against design performance and a determination of short term and long term actions recommended to sustain IWTS performance.

  8. Energy Conservation for Boiler Water Systems 

    E-print Network

    Beardsley, M. L.

    1981-01-01

    . This paper reviews methods to conserve energy in industrial boiler water systems. Both mechanical and chemical approaches for energy conservation are discussed. The important aspects of efficient combustion are covered as well as other mechanical factors...

  9. Captive Water Current Power System

    SciTech Connect

    Wuenscher, H. F.; Wuenscher, H. A.

    1984-01-31

    Current energy is converted into shaft power in two stages; First, buoyant power units with stationary hydrofoil wings reach faster than the current speed by sweeping out a captive path. Second, turbines at said power units convert the fast relative local current into shaft power. Power units sweeping along the water surface, using cycloidal turbine methods, as well as power units sweeping on a submerged path, using axial flow turbine methods, are described.

  10. Water system microbial check valve development

    NASA Technical Reports Server (NTRS)

    Colombo, G. V.; Greenley, D. R.; Putnam, D. F.

    1978-01-01

    A residual iodine microbial check valve (RIMCV) assembly was developed and tested. The assembly is designed to be used in the space shuttle potable water system. The RIMCV is based on an anion exchange resin that is supersaturated with an iodine solution. This system causes a residual to be present in the effluent water which provides continuing bactericidal action. A flight prototype design was finalized and five units were manufactured and delivered.

  11. Water

    MedlinePLUS

    ... consuming only bottled water or water from a filtration system that has been certified by an independent ... recommends using bottled water or water from a filtration system that has been certified by an independent ...

  12. Decision support system for drinking water management

    NASA Astrophysics Data System (ADS)

    Janža, M.

    2012-04-01

    The problems in drinking water management are complex and often solutions must be reached under strict time constrains. This is especially distinct in case of environmental accidents in the catchment areas of the wells that are used for drinking water supply. The beneficial tools that can help decision makers and make program of activities more efficient are decision support systems (DSS). In general they are defined as computer-based support systems that help decision makers utilize data and models to solve unstructured problems. The presented DSS was developed in the frame of INCOME project which is focused on the long-term stable and safe drinking water supply in Ljubljana. The two main water resources Ljubljana polje and Barje alluvial aquifers are characterized by a strong interconnection of surface and groundwater, high vulnerability, high velocities of groundwater flow and pollutant transport. In case of sudden pollution, reactions should be very fast to avoid serious impact to the water supply. In the area high pressures arising from urbanization, industry, traffic, agriculture and old environmental burdens. The aim of the developed DSS is to optimize the activities in cases of emergency water management and to optimize the administrative work regarding the activities that can improve groundwater quality status. The DSS is an interactive computer system that utilizes data base, hydrological modelling, and experts' and stakeholders' knowledge. It consists of three components, tackling the different abovementioned issues in water management. The first one utilizes the work on identification, cleaning up and restoration of illegal dumpsites that are a serious threat to the qualitative status of groundwater. The other two components utilize the predictive capability of the hydrological model and scenario analysis. The user interacts with the system by a graphical interface that guides the user step-by-step to the recommended remedial measures. Consequently, the acquisition of information to support the water management's decisions is simplified and faster, thus contributing to more efficient water management and a safer supply of drinking water.

  13. Hydro static water level systems at Fermilab

    SciTech Connect

    Volk, J.T.; Guerra, J.A.; Hansen, S.U.; Kiper, T.E.; Jostlein, H.; Shiltsev, V.; Chupyra, A.; Kondaurov, M.; Singatulin, S.

    2006-09-01

    Several Hydrostatic Water Leveling systems (HLS) are in use at Fermilab. Three systems are used to monitor quadrupoles in the Tevatron and two systems are used to monitor ground motion for potential sites for the International Linear Collider (ILC). All systems use capacitive sensors to determine the water level of water in a pool. These pools are connected with tubing so that relative vertical shifts between sensors can be determined. There are low beta quadrupoles at the B0 and D0 interaction regions of Tevatron accelerator. These quadrupoles use BINP designed and built sensors and have a resolution of 1 micron. All regular lattice superconducting quadrupoles (a total of 204) in the Tevatron use a Fermilab designed system and have a resolution of 6 microns. Data on quadrupole motion due to quenches, changes in temperature will be presented. In addition data for ground motion for ILC studies caused by natural and cultural factors will be presented.

  14. Design of water quality information systems

    NASA Astrophysics Data System (ADS)

    AGU cooperated with sponsors Colorado State University, Fort Collins, and the U.S. Environmental Protection Agency in presenting the International Symposium on the Design of Water Quality Information Systems, June 7-9, 1989, in Fort Collins. There were 44 papers presented to the 125 symposium participants (see photo).In the keynote address, Marshall Moss (AGU General Secretary and U.S. Geological Survey, Tucson, Ariz.) described the evolution of water quality monitoring in an “information” age. He noted that if we are to bring what we have traditionally called “water quality monitoring” into the information age, we must couple decision technology with information technology at the system design stage. Representatives of national and local government and industry described how they are attempting to couple their water quality decisions with their “information” system.

  15. Emerging problems with zoonotic bacteria in intensive warm water fish culture: facts and risks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With the development of warm water aquaculture in intensive indoor recirculation systems in Europe and the United States new bacterial disease problems occur, especially in the cultured fish, and in humans. These so called zoonotic bacteria are more frequently isolated from severe disease outbreaks...

  16. Pulsed Magnet Arc Designs for Recirculating Linac Muon Accelerators

    SciTech Connect

    K.B. Beard, R.P. Johnson, S.A. Bogacz, G.M. Wang

    2009-05-01

    Recirculating linear accelerators (RLAs) using both pulsed quadrupoles and pulsed dipoles can be used to quickly accelerate muons in the 3 – 2000 GeV range. Estimates on the requirements for the pulsed quadrupoles and dipoles are presented.

  17. Recirculation of Factory Heat and Air to Reduce Energy Consumption 

    E-print Network

    Thiel, G. R.

    1983-01-01

    Two methods for achieving substantial energy savings through recirculation techniques are discussed: 1. Air cleaning methods that can be used to recover the energy content of previously-exhausted ventilation air in many manufacturing plants...

  18. ULTRASONIC INSPECTION OF A SECTION OF THE NS SAVANNAH PRIMARY PIPING SYSTEM

    Microsoft Academic Search

    Johnson

    1963-01-01

    A section of NS Savannah primary pipe and part of a primary system gate ; valve were examined ultrasonically to determine whether a fluctuating flow of low-; temperature makeup water entering through a nozzle in the valve hsnd damaged the ; components during service. Examination was prompted by failure of a Vallecitos ; Boiling Water Reactor (VBWR) recirculating pipe in

  19. Practical design and application of airlift technology for aquaculture reuse systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Air-lift technology to support water movement in low-head water treatment units for recirculating aquacultures systems provides an energy efficient alternative to the use of centrifugal pumps. The benefits of air-lift are further realized when electrical requirements for aeration, CO2 degassing, and...

  20. Media configuration and recirculation of upflow anaerobic floating filter for piggery wastewater treatment

    Microsoft Academic Search

    Seunghwan Lee; Hongshin Lee; Seongeok Lee; Sukhuma Chitapornpan; Chart Chiemchaisri; Chongrak Polprasert; Kyuhong Ahn

    2007-01-01

    An upflow anaerobic floating filter media (UAFF) reactor was applied to the treatment of synthetic and real piggery wastewater.\\u000a The effect of media configuration and internal recirculation on the system performance was studied. In the first experiment,\\u000a three-UAFF reactors filled with different media, i.e., polypropylene beads, sponge cubes and coconut fiber were continuously\\u000a fed with synthetic wastewater at upflow velocity

  1. BIOFILMS IN DRINKING WATER DISTRIBUTION SYSTEMS

    EPA Science Inventory

    Virtually anywhere a surface comes into contact with the water in a distribution system, one can find biofilms. Biofilms are formed in distribution system pipelines when microbial cells attach to pipe surfaces and multiply to form a film or slime layer on the pipe. Probably withi...

  2. Engineering aspects of water pollution control systems

    Microsoft Academic Search

    R. G. Dalbke; A. J. Turk

    1967-01-01

    The importance of proper engineering when providing pollution control systems is emphasized. Organization of engineering projects is described in detail. Included are discussions of: (1) collection and evaluation of available data; (2) establishment of survey and test program; (3) integration and evaluation of findings; (4) establishment of pollution control and water utilization systems; and (5) specification and detailed design preparation.

  3. GIS-BASED WATER BALANCE SYSTEM FOR INTEGRATED SUSTAINABILITY MANAGEMENT OF WATER DISTRIBUTION ASSETS

    Microsoft Academic Search

    Delta Regina Hotel; Saskatchewan Regina; Mahmoud R. Halfawy; Osama Hunaidi

    Water loss from water distribution systems is a major concern to water utilities. Water utilities around the world are becoming more focused on adopting a proactive approach to managing water loss. The amount of lost water can be significant, reaching levels as high as 50% of production. However, water loss management is still not widely practiced by utilities in North

  4. In-situ continuous water monitoring system

    DOEpatents

    Thompson, Cyril V. (Knoxville, TN); Wise, Marcus B. (Kingston, TN)

    1998-01-01

    An in-situ continuous liquid monitoring system for continuously analyzing volatile components contained in a water source comprises: a carrier gas supply, an extraction container and a mass spectrometer. The carrier gas supply continuously supplies the carrier gas to the extraction container and is mixed with a water sample that is continuously drawn into the extraction container by the flow of carrier gas into the liquid directing device. The carrier gas continuously extracts the volatile components out of the water sample. The water sample is returned to the water source after the volatile components are extracted from it. The extracted volatile components and the carrier gas are delivered continuously to the mass spectrometer and the volatile components are continuously analyzed by the mass spectrometer.

  5. Alternative Electrochemical Systems for Ozonation of Water

    NASA Technical Reports Server (NTRS)

    Andrews, Craig C.; Murphy, Oliver J.

    2003-01-01

    Electrochemical systems that are especially well suited for the small-scale generation of ozone and ozonated water for local use have been invented. These systems can operate with very little maintenance, and the only inputs needed during operation are electric power and water. Ozonated water produced by these systems can be used in diverse industrial applications: A few examples include sterilization in the brewing industry, general disinfection, and treatment of sewage and recycled water. The basic principle of operation admits of several alternative system configurations. The heart of the system is a stack of electrolytic cells, each containing a proton-exchange membrane (which serves as a solid electrolyte) sandwiched between a catalytic anode and a catalytic cathode. Preferably, the proton-exchange membrane is made of a perfluorinated sulfonic acid polymer. During electrolysis, a mixture of O2 and O3 gases is generated at the anode and H2 is generated at the cathode. Some of the O3 generated at the anode becomes dissolved in the water. The proportion of O3 in the O2/O3 mixture can be maximized by the selection of suitable electrode materials and the use of a high overpotential. Although the proton-exchange membrane conducts protons, it does not conduct electrons. It is also impermeable by gases; consequently, it maintains separation between the O2/O3 mixture evolved at the anode and the H2 evolved at the cathode.

  6. An expert system for water quality modelling.

    PubMed

    Booty, W G; Lam, D C; Bobba, A G; Wong, I; Kay, D; Kerby, J P; Bowen, G S

    1992-12-01

    The RAISON-micro (Regional Analysis by Intelligent System ON a micro-computer) expert system is being used to predict the effects of mine effluents on receiving waters in Ontario. The potential of this system to assist regulatory agencies and mining industries to define more acceptable effluent limits was shown in an initial study. This system has been further developed so that the expert system helps the model user choose the most appropriate model for a particular application from a hierarchy of models. The system currently contains seven models which range from steady state to time dependent models, for both conservative and nonconservative substances in rivers and lakes. The menu driven expert system prompts the model user for information such as the nature of the receiving water system, the type of effluent being considered, and the range of background data available for use as input to the models. The system can also be used to determine the nature of the environmental conditions at the site which are not available in the textual information database, such as the components of river flow. Applications of the water quality expert system are presented for representative mine sites in the Timmins area of Ontario. PMID:24227087

  7. Experiments on the operation of a combined aquaculture-algae system

    Microsoft Academic Search

    Dénes Gál; Ferenc Pekár; Éva Kerepeczki; László Váradi

    2007-01-01

    A combined aquaculture-algae system was developed for the purification and reuse of effluent water from intensive fish production\\u000a in a combination of a high-rate algal pond and extensive fishpond. The integrated system was operated as a closed system,\\u000a thus the water demand was reduced through the recirculation of the treated water. The pilot-scale experimental system consisted\\u000a of three different compartments:

  8. Resources for Small Water Systems in Texas 

    E-print Network

    Dozier, Monty; Theodori, Gene L.; Jensen, Ricard

    2007-03-28

    an application is received. Applica- tions for competitive funding programs are reviewed and scored using program-specifi c criteria and processes. Eligible projects may in- clude colonia infrastructure, community plan- ning for public infrastructure, and water... Texas (Alice) and the High Plains (Levelland) provide on- site training and technical assistance. ORCA staff at these fi eld offi ces can help communi- ties develop loan and grant applications for water and wastewater systems. The Texas Engineering...

  9. Energy optimization of water distribution system

    SciTech Connect

    Not Available

    1993-02-01

    In order to analyze pump operating scenarios for the system with the computer model, information on existing pumping equipment and the distribution system was collected. The information includes the following: component description and design criteria for line booster stations, booster stations with reservoirs, and high lift pumps at the water treatment plants; daily operations data for 1988; annual reports from fiscal year 1987/1988 to fiscal year 1991/1992; and a 1985 calibrated KYPIPE computer model of DWSD`s water distribution system which included input data for the maximum hour and average day demands on the system for that year. This information has been used to produce the inventory database of the system and will be used to develop the computer program to analyze the system.

  10. Water Resources Data System State Climate Office

    NSDL National Science Digital Library

    The Water Resources Data System is a "clearinghouse of hydrological and climatological data for the State of Wyoming" provided by the University of Wyoming. Online data include a water quality database, climatological data (such as snow depth and precipitation), and earthquake and landslide data. A water library link contains research briefs, publications, a reference shelf, newsletters, and other related documents. Additional links on the main page include US Geological Survey stream flow conditions, the state climatologist office, data clearinghouses, and other Wyoming-specific informational sites.

  11. Running hot water: A systems approach to energy conservation

    Microsoft Academic Search

    P. Wulff

    1982-01-01

    Ways to conserve energy in domestic hot water systems are discussed. Examination of the Swedish situation shows that centralized systems, where water heating is a subsidiary of space heating, waste energy because water cools in the pipes after use, and the entire system must operate in summer. Also, water temperature is often much higher than required. Solar panels, individual water

  12. Removal of sodium chloride from human urine via batch recirculation electrodialysis at constant applied voltage

    NASA Technical Reports Server (NTRS)

    Gordils-Striker, Nilda E.; Colon, Guillermo

    2003-01-01

    The removal of sodium chloride (NaCl) from human urine using a six-compartment electrodialysis cell with batch recirculation mode of operation for use in advanced life support systems (ALSS) was studied. From the results obtained, batch recirculation at constant applied voltage yields high values (approximately 94% of NaCl removal. Based on the results, the initial rate of NaCl removal was correlated to a power function of the applied voltage: -r=2.0 x 10(-4)E(3.8). With impedance spectroscopy methods, it was also found that the anion membranes were more affected by fouling with an increase of the ohmic resistance of almost 11% compared with 7.4% for the cationic ones.

  13. LUX - A recirculating linac-based ultrafast X-ray source

    SciTech Connect

    Corlett, J.N.; Barletta, W.A.; DeSantis, S.; Doolittle, L.; Fawley, W.M.; Green, M.A.; Heimann, P.; Leone, S.R.; Lidia, S.; Li, D.; Parmigiani, F.; Ratti, A.; Robinson, K.; Schoenlein, R.; Staples, J.; Wan, W.; Wells, R.; Wilcox, R.; Wolski, A.; Zholents, A.

    2003-08-01

    We describe the design of a proposed source of ultra-fast synchrotron radiation x-ray pulses based on a recirculating superconducting linac, with an integrated array of ultrafast laser systems. The source produces x-ray pulses with duration of 10-50 fs at a 10 kHz repetition rate, with tunability from EUV to hard x-ray regimes, and optimized for the study of ultra-fast dynamics. A high-brightness rf photocathode provides electron bunches. An injector linac accelerates the beam to the 100 MeV range, and is followed by four passes through a 700 MeV recirculating linac. Ultrafast hard x-ray pulses are obtained by a combination of electron bunch manipulation, transverse temporal correlation of the electrons, and x-ray pulse compression. EUV and soft x-ray pulses as short as 10 fs are generated in a harmonic-cascade free electron laser scheme.

  14. Wheat Response to Differences In Water and Nutritional Status Between Zeoponic and Hydroponic Growth Systems

    NASA Technical Reports Server (NTRS)

    Steinberg, Susan L.; Ming, Douglas W.; Henderson, Keith E.; Carrier, Chris; Gruener, John E.; Barta, Dan J.; Henninger, Don L.

    1999-01-01

    Hydroponic culture has traditionally been used for controlled environment life support systems (CELSS) because the optimal environment for roots supports high growth rates. Recent developments in zeoponic substrate and microporous tube irrigation (ZPT) also offer high control of the root environment. This study compared the effect of differences in water and nutrient status of ZPT or hydroponic culture on growth and yield of wheat (Triticum aestivum L., CV 'USU-Apogee'). In a side-by-side test in a controlled environment, wheat was grown in ZPT and recirculating hydroponics to maturity. Water use by plants grown in both culture systems peaked at 15-20 L per square meters per d up to day 40, after which it declined more rapidly for plants grown in ZPT culture due to earlier senescence of leaves. No consistent differences were noted in water status between plants grown in the two culture systems. Although yield was similar, harvest index was 28% lower for plants grown in ZPT versus hydroponic culture. Sterile green tillers made up 12% and 0% of the biomass of plants grown in ZPT and hydroponic culture, respectively. Differences in biomass partitioning were attributed primarily to NH4 -N nutrition of plants grown in ZPT as compared with NO3-N in hydroponic nutrient solution. It was likely that NH4-N induced Ca deficiency produced excess tillering and lower harvest index for plants grown in ZPT culture. These results suggest that further refinements in zeoponic substrate would make ZPT culture a viable alternative for achieving high productivity in a CELSS.

  15. Wheat response to differences in water and nutritional status between zeoponic and hydroponic growth systems.

    PubMed

    Steinberg, S L; Ming, D W; Henderson, K E; Carrier, C; Gruener, J E; Barta, D J; Henninger, D L

    2000-01-01

    Hydroponic culture has traditionally been used for controlled environment life support systems (CELSS) because the optimal environment for roots supports high growth rates. Recent developments in zeoponic substrate and microporous tube irrigation (ZPT) also offer high control of the root environment. This study compared the effect of differences in water and nutrient status of ZPT or hydroponic culture on growth and yield of wheat (Triticum aestivum L. cv. USU-Apogee). In a side-by-side test in a controlled environment, wheat was grown in ZPT and recirculating hydroponics to maturity. Water use by plants grown in both culture systems peaked at 15 to 20 L m-2 d-1 up to Day 40, after which it declined more rapidly for plants grown in ZPT culture due to earlier senescence of leaves. No consistent differences in water status were noted between plants grown in the two culture systems. Although yield was similar, harvest index was 28% lower for plants grown in ZPT than in hydroponic culture. Sterile green tillers made up 12 and 0% of the biomass of plants grown in ZPT and hydroponic culture, respectively. Differences in biomass partitioning were attributed primarily to NH4-N nutrition of plants grown in ZPT compared with NO3-N in hydroponic nutrient solution. It is probable that NH4-N-induced Ca deficiency produced excess tillering and lower harvest index for plants grown in ZPT culture. These results suggest that further refinements in zeoponic substrate would make ZPT culture a viable alternative for achieving high productivity in a CELSS. PMID:11543523

  16. Wheat response to differences in water and nutritional status between zeoponic and hydroponic growth systems

    NASA Technical Reports Server (NTRS)

    Steinberg, S. L.; Ming, D. W.; Henderson, K. E.; Carrier, C.; Gruener, J. E.; Barta, D. J.; Henninger, D. L.

    2000-01-01

    Hydroponic culture has traditionally been used for controlled environment life support systems (CELSS) because the optimal environment for roots supports high growth rates. Recent developments in zeoponic substrate and microporous tube irrigation (ZPT) also offer high control of the root environment. This study compared the effect of differences in water and nutrient status of ZPT or hydroponic culture on growth and yield of wheat (Triticum aestivum L. cv. USU-Apogee). In a side-by-side test in a controlled environment, wheat was grown in ZPT and recirculating hydroponics to maturity. Water use by plants grown in both culture systems peaked at 15 to 20 L m-2 d-1 up to Day 40, after which it declined more rapidly for plants grown in ZPT culture due to earlier senescence of leaves. No consistent differences in water status were noted between plants grown in the two culture systems. Although yield was similar, harvest index was 28% lower for plants grown in ZPT than in hydroponic culture. Sterile green tillers made up 12 and 0% of the biomass of plants grown in ZPT and hydroponic culture, respectively. Differences in biomass partitioning were attributed primarily to NH4-N nutrition of plants grown in ZPT compared with NO3-N in hydroponic nutrient solution. It is probable that NH4-N-induced Ca deficiency produced excess tillering and lower harvest index for plants grown in ZPT culture. These results suggest that further refinements in zeoponic substrate would make ZPT culture a viable alternative for achieving high productivity in a CELSS.

  17. AOIPS water resources data management system

    NASA Technical Reports Server (NTRS)

    Merritt, E. S.; Shotwell, R. L.; Place, M. C.; Belknap, N. J.

    1976-01-01

    A geocoded data management system applicable for hydrological applications was designed to demonstrate the utility of the Atmospheric and Oceanographic Information Processing System (AOIPS) for hydrological applications. Within that context, the geocoded hydrology data management system was designed to take advantage of the interactive capability of the AOIPS hardware. Portions of the Water Resource Data Management System which best demonstrate the interactive nature of the hydrology data management system were implemented on the AOIPS. A hydrological case study was prepared using all data supplied for the Bear River watershed located in northwest Utah, southeast Idaho, and western Wyoming.

  18. Introduction of Heat Recovery Chiller Control and Water System Design

    E-print Network

    Jia, J.

    2006-01-01

    The styles, feature and main concerns of heat recovery water system are discussed, and the entering condenser water temperature control is recommended for higher chiller efficiency and reliable operation. Three optimized water system designs...

  19. 40 CFR 258.51 - Ground-water monitoring systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Ground-water monitoring systems. 258.51 Section...MUNICIPAL SOLID WASTE LANDFILLS Ground-Water Monitoring and Corrective Action § 258.51 Ground-water monitoring systems. (a) A...

  20. 40 CFR 258.51 - Ground-water monitoring systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2011-07-01 true Ground-water monitoring systems. 258.51 Section...MUNICIPAL SOLID WASTE LANDFILLS Ground-Water Monitoring and Corrective Action § 258.51 Ground-water monitoring systems. (a) A...

  1. 40 CFR 258.51 - Ground-water monitoring systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Ground-water monitoring systems. 258.51 Section...MUNICIPAL SOLID WASTE LANDFILLS Ground-Water Monitoring and Corrective Action § 258.51 Ground-water monitoring systems. (a) A...

  2. 40 CFR 258.51 - Ground-water monitoring systems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Ground-water monitoring systems. 258.51 Section...MUNICIPAL SOLID WASTE LANDFILLS Ground-Water Monitoring and Corrective Action § 258.51 Ground-water monitoring systems. (a) A...

  3. 40 CFR 258.51 - Ground-water monitoring systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Ground-water monitoring systems. 258.51 Section...MUNICIPAL SOLID WASTE LANDFILLS Ground-Water Monitoring and Corrective Action § 258.51 Ground-water monitoring systems. (a) A...

  4. Introduction of Heat Recovery Chiller Control and Water System Design 

    E-print Network

    Jia, J.

    2006-01-01

    The styles, feature and main concerns of heat recovery water system are discussed, and the entering condenser water temperature control is recommended for higher chiller efficiency and reliable operation. Three optimized water system designs...

  5. 33 CFR 127.1507 - Water systems for fire protection.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Equipment § 127.1507 Water systems for fire protection...handling LHG must have a supply of water and a means for distributing...the vessel. (b) Each water system must fully and simultaneously supply, for at least 2...

  6. 33 CFR 127.1507 - Water systems for fire protection.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Equipment § 127.1507 Water systems for fire protection...handling LHG must have a supply of water and a means for distributing...the vessel. (b) Each water system must fully and simultaneously supply, for at least 2...

  7. 33 CFR 127.1507 - Water systems for fire protection.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Equipment § 127.1507 Water systems for fire protection...handling LHG must have a supply of water and a means for distributing...the vessel. (b) Each water system must fully and simultaneously supply, for at least 2...

  8. 69 FR 59836 - Household Water Well System Grant Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2004-10-06

    ...DEPARTMENT OF AGRICULTURE Rural Utilities...0572-AB93 Household Water Well System Grant...States Department of Agriculture's Rural Development...establish the Household Water System Program as...Loan Specialist, Water Programs Division...Department of Agriculture, 1400...

  9. 69 FR 59764 - Household Water Well System Grant Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2004-10-06

    ...DEPARTMENT OF AGRICULTURE Rural Utilities...0572-AB93 Household Water Well System Grant...Loan Specialist, Water Programs Division...Department of Agriculture, 1400 Independence...maintenance on a water well system or portion...States Department of Agriculture. Sec....

  10. Hot Water Heating System Operation and Energy Conservation

    E-print Network

    Shao, Z.; Chen, H.; Wei, P.

    2006-01-01

    Based on an example of the reconstruction of a hot water heating system, this paper provides an analysis and comparison of the operations of hot water heating systems, including supply water temperature adjustment, flow adjustment during each...

  11. Water film thickness in the clay-water system

    NASA Astrophysics Data System (ADS)

    Makihara, Hiroshi

    The permeable press experiment was performed for aqueous clay mineral systems to understand the relationship between the water film thickness and the applied permeable pressure. Water film thickness between particles was calculated from the particle size and the linear drying shrinkage of pressed bodies. The permeable press experimental results were compared to the calculated total interaction pressures between particles using the DLVO theory. The kaolinite and the metakaolinite had the same particle shape. Kaolinite particles were crystalline, and metakaolinite particles were short-range order. The kaolinite had the point of zero net charge, PZNC, at pH 5.7. However, the kaolinite showed multi-cross points at pHs 4.6, 5.7, 6.2, and 7.2. These multi-cross points were in agreement with the theoretical titration using the two-site surface complex reaction model by Carroll-Webb and Walther. On other hand, the metakaolinite had the PZNC at pH 7.2 as a common intersection point. If the zeta potential at pHpzNc is identical to the silica basal surface potential, the silica surface charge densities are calculated as -2.6 muC cm-2 for the kaolinite and -2.7 muC cm -2 for the metakaolinite, respectively. The calculated surface charge density is equivalent to one aluminum atom substituted in 54 silicon atoms in the silica tetrahedral layer. The total interaction pressures using the DLVO theory corresponded to the permeable press experimental results of the metakaolinite-0.1 M NaCl systems. The surface of the metakaolinite was estimated to have immobile water layers between 5 and 8 molecules thick. The metakaolinite samples cracked in experiments when the applied permeable pressure increased. This phenomenon can be explained by a vanishing capillary pressure: contacting immobile layers. The permeable press experimental results of all the kaolinite systems were significantly higher than the calculated total interaction pressures. The slope of the natural log of the permeable pressure and the water film thickness of the kaolinite systems indicated the existence of a longer-range repulsive pressure than that of the metakaolnite systems. The DLVO theory cannot explain the kaolinite systems because the nature of materials, such as an atomic configuration of the surface, which induces the structural forces, is not considered.

  12. [Case study of red water phenomenon in drinking water distribution systems caused by water source switch].

    PubMed

    Wang, Yang; Zhang, Xiao-jian; Chen, Chao; Pan, An-jun; Xu, Yang; Liao, Ping-an; Zhang, Su-xia; Gu, Jun-nong

    2009-12-01

    Red water phenomenon occurred in some communities of a city in China after water source switch in recent days. The origin of this red water problem and mechanism of iron release were investigated in the study. Water quality of local and new water sources was tested and tap water quality in suffered area had been monitored for 3 months since red water occurred. Interior corrosion scales on the pipe which was obtained from the suffered area were analyzed by XRD, SEM, and EDS. Corrosion rates of cast iron under the conditions of two source water were obtained by Annular Reactor. The influence of different source water on iron release was studied by pipe section reactor to simulate the distribution systems. The results indicated that large increase of sulfate concentration by water source shift was regarded as the cause of red water problem. The Larson ratio increased from about 0.4 to 1.7-1.9 and the red water problem happened in the taps of some urban communities just several days after the new water source was applied. The mechanism of iron release was concluded that the stable shell of scales in the pipes had been corrupted by this kind of high-sulfate-concentration source water and it was hard to recover soon spontaneously. The effect of sulfate on iron release of the old cast iron was more significant than its effect on enhancing iron corrosion. The rate of iron release increased with increasing Larson ratio, and the correlation of them was nonlinear on the old cast-iron. The problem remained quite a long time even if the water source re-shifted into the blended one with only small ratio of the new source and the Larson ratio reduced to about 0.6. PMID:20187386

  13. Aircraft Recirculation Filter for Air-Quality and Incident Assessment

    PubMed Central

    Eckels, Steven J.; Jones, Byron; Mann, Garrett; Mohan, Krishnan R.; Weisel, Clifford P.

    2015-01-01

    The current research examines the possibility of using recirculation filters from aircraft to document the nature of air-quality incidents on aircraft. These filters are highly effective at collecting solid and liquid particulates. Identification of engine oil contaminants arriving through the bleed air system on the filter was chosen as the initial focus. A two-step study was undertaken. First, a compressor/bleed air simulator was developed to simulate an engine oil leak, and samples were analyzed with gas chromatograph-mass spectrometry. These samples provided a concrete link between tricresyl phosphates and a homologous series of synthetic pentaerythritol esters from oil and contaminants found on the sample paper. The second step was to test 184 used aircraft filters with the same gas chromatograph-mass spectrometry system; of that total, 107 were standard filters, and 77 were nonstandard. Four of the standard filters had both markers for oil, with the homologous series synthetic pentaerythritol esters being the less common marker. It was also found that 90% of the filters had some detectable level of tricresyl phosphates. Of the 77 nonstandard filters, 30 had both markers for oil, a significantly higher percent than the standard filters. PMID:25641977

  14. Efficiency of an AMTEC recirculating test cell, experiments and projections

    NASA Astrophysics Data System (ADS)

    Underwood, M. L.; O'Connor, D.; Williams, R. M.; Jeffries-Nakamura, B.; Ryan, M. A.

    The alkali metal thermal to electric converter (AMTEC) is an electrochemical device for the direct conversion of heat to electrical energy with efficiencies potentially near Carnot. The future usefulness of AMTEC for space power conversion depends on the efficiency of the devices. Systems studies have projected from 15 to 35 percent thermal to electric conversion efficiencies, and one experiment has demonstrated 19 percent efficiency for a short period of time. Recent experiments in a recirculating test cell (RTC) have demonstrated sustained conversion efficiencies as high as 10.2 percent early in cell life and 9.7 percent after maturity. Extensive thermal and electrochemical analysis of the cell during several experiments demonstrated that the efficiency could be improved in two ways. First, the electrode performance could be improved. The electrode for these tests operated at about one third the power density of state of the art electrodes. The low power density was caused by a combination of high series resistance and high mass flow resistance. Reducing these resistances could improve the efficiency to greater than 10 percent. Second, the cell thermal performance could be improved. Efficiencies greater than 14 percent could be realized through reducing the radiative thermal loss. Further improvements to the efficiency range predicted by systems studies can be accomplished through the development and use of an advanced condenser with improved reflectivity, close to that of a smooth sodium film, and the series connecting of individual cells to further reduce thermal losses.

  15. Efficiency of an AMTEC recirculating test cell, experiments, and projections

    NASA Astrophysics Data System (ADS)

    Underwood, M. L.; Oconnor, D.; Williams, R. M.; Jeffries-Nakamura, B.; Ryan, M. A.

    1992-05-01

    The alkali metal thermal to electric converter (AMTEC) is an electrochemical device for the direct conversion of heat to electrical energy with efficiencies potentially near Carnot. The future usefulness of AMTEC for space power conversion depends on the efficiency of the devices. Systems studies have projected from 15 to 35 percent thermal to electric conversion efficiencies, and one experiment has demonstrated 19 percent efficiency for a short period of time. Recent experiments in a recirculating test cell (RTC) have demonstrated sustained conversion efficiencies as high as 10.2 percent early in cell life and 9.7 percent after maturity. Extensive thermal and electrochemical analysis of the cell during several experiments demonstrated that the efficiency could be improved in two ways. First, the electrode performance could be improved. The electrode for these tests operated at about one third the power density of state of the art electrodes. The low power density was caused by a combination of high series resistance and high mass flow resistance. Reducing these resistances could improve the efficiency to greater than 10 percent. Second, the cell thermal perform ance could be improved. Efficiencies greater than 14 percent could be realized through reducing the radiative thermal loss. Further improvements to the efficiency range predicted by systems studies can be accomplished through the development and use of an advanced condenser with improved reflectivity, close to that of a smooth sodium film, and the series connecting of individual cells to further reduce thermal losses.

  16. Efficiency of an AMTEC recirculating test cell, experiments and projections

    SciTech Connect

    Underwood, M.L.; O`Connor, D.; Williams, R.M.; Jeffries-Nakamura, B.; Ryan, M.A.

    1992-05-01

    The alkali metal thermal to electric converter (AMTEC) is an electrochemical device for the direct conversion of heat to electrical energy with efficiencies potentially near Carnot. The future usefulness of AMTEC for space power conversion depends on the efficiency of the devices. Systems studies have projected from 15% to 35% thermal to electric conversion efficiencies, and one experiment has demonstrated 19% efficiency for a short period of time. Recent experiments in a recirculating test cell (RTC) have demonstrated sustained conversion efficiencies as high as 10.2% early in cell life and 9.7% after maturity. Extensive thermal and electrochemical analysis of the cell during several experiments demonstrated that the efficiency could be improved in two ways. First, the electrode performance could be improved. The electrode for these tests operated at about one third the power density of state of the art electrodes. The low power density was caused by a combination of high series resistance and high mass flow resistance. Reducing these resistances could improve the efficiency to greater than 10%. Second, the cell thermal performance could be improved. Efficiencies greater than 14% could be realized through reducing the radiative thermal loss. Further improvements to the efficiency range predicted by systems studies can be accomplished through the development and use of an advanced condenser with improved reflectivity, close to that of a smooth sodium film, and the series connecting of individual cells to further reduce thermal losses.

  17. Competition for water for the food system

    PubMed Central

    Strzepek, Kenneth; Boehlert, Brent

    2010-01-01

    Although the global agricultural system will need to provide more food for a growing and wealthier population in decades to come, increasing demands for water and potential impacts of climate change pose threats to food systems. We review the primary threats to agricultural water availability, and model the potential effects of increases in municipal and industrial (M&I) water demands, environmental flow requirements (EFRs) and changing water supplies given climate change. Our models show that, together, these factors cause an 18 per cent reduction in the availability of worldwide water for agriculture by 2050. Meeting EFRs, which can necessitate more than 50 per cent of the mean annual run-off in a basin depending on its hydrograph, presents the single biggest threat to agricultural water availability. Next are increases in M&I demands, which are projected to increase upwards of 200 per cent by 2050 in developing countries with rapidly increasing populations and incomes. Climate change will affect the spatial and temporal distribution of run-off, and thus affect availability from the supply side. The combined effect of these factors can be dramatic in particular hotspots, which include northern Africa, India, China, parts of Europe, the western US and eastern Australia, among others. PMID:20713394

  18. Wash water waste pretreatment system study

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The use of real wash water had no adverse effect on soap removal when an Olive Leaf soap based system was used; 96 percent of the soap was removed using ferric chloride. Numerous chemical agents were evaluated as antifoams for synthetic wash water. Wash water surfactants used included Olive Leaf Soap, Ivory Soap, Neutrogena and Neutrogena Rain Bath Gel, Alipal CO-436, Aerosol 18, Miranol JEM, Palmeto, and Aerosol MA-80. For each type of soapy wash water evaluated, at least one antifoam capable of causing nonpersistent foam was identified. In general, the silicones and the heavy metal ions (i.e., ferric, aluminum, etc.) were the most effective antifoams. Required dosage was in the range of 50 to 200 ppm.

  19. Exhaust-gas recirculation for retrofit NOx control on natural gas engines. Topical report, January-April 1988

    Microsoft Academic Search

    1989-01-01

    Data on exhaust-gas recirculation obtained from Tenneco Gas Transportation Company were reviewed and analyzed, and a basic EGR system design and cost estimate were developed. EGR can provide practical NOx reductions of up to 50% in 2-cycle natural gas engines. The amount of NO reduction achievable is dependent on the initial baseline NOx emissions of the engine. On the basis

  20. Distribution of Off-Flavor Compounds and Isolation of Geosmin-Producing Bacteria in a Series of Water Recirculating Systems for Rainbow Trout Culture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pre-harvest “off-flavor” in aquaculture products results in large economic losses to producers due to delayed harvest. The common off-flavors “earthy” and “musty” are due to the presence of geosmin and 2-methylisoborneol (MIB), respectively. Although certain species of cyanobacteria are responsibl...

  1. Water Treatment Systems for Long Spaceflights

    NASA Technical Reports Server (NTRS)

    FLynn, Michael T.

    2012-01-01

    Space exploration will require new life support systems to support the crew on journeys lasting from a few days to several weeks, or longer. These systems should also be designed to reduce the mass required to keep humans alive in space. Water accounts for about 80 percent of the daily mass intake required to keep a person alive. As a result, recycling water offers a high return on investment for space life support. Water recycling can also increase mission safety by providing an emergency supply of drinking water, where another supply is exhausted or contaminated. These technologies also increase safety by providing a lightweight backup to stored supplies, and they allow astronauts to meet daily drinking water requirements by recycling the water contained in their own urine. They also convert urine into concentrated brine that is biologically stable and nonthreatening, and can be safely stored onboard. This approach eliminates the need to have a dedicated vent to dump urine overboard. These needs are met by a system that provides a contaminant treatment pouch, referred to as a urine cell or contaminant cell, that converts urine or another liquid containing contaminants into a fortified drink, engineered to meet human hydration, electrolyte, and caloric requirements, using a variant of forward osmosis (FO) to draw water from a urine container into the concentrated fortified drink as part of a recycling stage. An activated carbon pretreatment removes most organic molecules. Salinity of the initial liquid mix (urine plus other) is synergistically used to enhance the precipitation of organic molecules so that activated carbon can remove most of the organics. A functional osmotic bag is then used to remove inorganic contaminants. If a contaminant is processed for which the saline content is different than optimal for precipitating organic molecules, the saline content of the liquid should be adjusted toward the optimal value for that contaminant. A first urine treatment method converts urine into a fortified sports drink, resembling Gatorade, using a first urine cell.

  2. Agricultural-to-hydropower water transfers: sharing water and benefits in hydropower-irrigation systems

    Microsoft Academic Search

    A. Tilmant; Q. Goor; D. Pinte

    2009-01-01

    This paper presents a methodology to assess agricultural-to-hydropower water transfers in water resources systems where irrigation crop production and hydropower generation are the main economic activities. In many countries, water for crop irrigation is often considered as a static asset: irrigation water is usually allocated by a system of limited annual rights to use a prescribed volume of water. The

  3. The Carbonate System in Natural Waters

    Microsoft Academic Search

    Hector Bustos-Serrano

    2010-01-01

    Reliable measurements of the thermodynamics of the carbonate system are needed to better understand the CO2 system in natural waters. New measurements of the carbonic acid pK1* and pK2* in seawater have been made over a wide range of temperatures (1 to 50°C) and salinities. The commonly used CO2 constants of Mehrbach et al., (1973) were limited to salinities (19

  4. Water electrolysis system refurbishment and testing

    NASA Technical Reports Server (NTRS)

    Greenough, B. M.

    1972-01-01

    The electrolytic oxygen generator for the back-up water electrolysis system in a 90-day manned test was refurbished, improved and subjected to a 182-day bench test. The performance of the system during the test demonstrated the soundness of the basic electrolysis concept, the high development status of the automatic controls which allowed completely hands-off operation, and the capability for orbital operation. Some design improvements are indicated.

  5. Prototype solar heating and hot water system

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Progress is reported in the development of a solar heating and hot water system which uses a pyramidal optics solar concentrator for heating, and consists of the following subsystems: collector, control, transport, and site data acquisition. Improvements made in the components and subsystems are discussed.

  6. SMALL DRINKING WATER SYSTEM PEER REVIEW PROGRAM

    EPA Science Inventory

    The United South and Eastern Tribes, Inc., which is made up of twenty-four (24) tribes, ranging in location, geographically, from Maine to Texas, AND three (3) states, Mississippi, Kentucky, and Georgia, participated in a program, "The Small Drinking Water System Peer Review Prog...

  7. LIGHTWEIGHT GREEN ROOF WATER RETENTION SYSTEM

    EPA Science Inventory

    During Phase I, we have forged numerous necessary partnerships, which will allow us to begin our implementation tests. Working with the Philadelphia Water Department (PWD) and Drexel Smart House (DSH) we have 3 to 4 prime test sites for our system. We plan to execute our insta...

  8. COST FOR WATER SUPPLY DISTRIBUTION SYSTEM REHABILITATION

    EPA Science Inventory

    A major challenge for the society in the twenty-first century will be design, rehabilitation, replacement, and optimal management of drinking water distribution systems. A recent survey conducted by the USEPA found that $138B will be needed to maintain and replace existing drinki...

  9. Water Supply Network System Control based on Model Predictive Control

    Microsoft Academic Search

    Nagib G. N. Mohammed; Adel Abdulrahman

    2009-01-01

    An increasing demand for water due to population growth, industrial development and improvement of economic require management of water transfer and improve operation of water supply systems. This paper considers the application of a model predictive control (MPC) technique to improve the behavior of the water network supply system, to maintain stable operation of the water flow rate, and reduce

  10. Deficiencies in drinking water distribution systems in developing countries

    Microsoft Academic Search

    Ellen J. Lee; Kellogg J. Schwab

    2005-01-01

    Rapidly growing populations and migration to urban areas in developing countries has resulted in a vital need for the establishment of centralized water systems to disseminate potable water to residents. Protected source water and modern, well-maintained drinking water treatment plants can provide water adequate for human consumption. However, ageing, stressed or poorly maintained distribution systems can cause the quality of

  11. Unified hot water and forced air heating system

    Microsoft Academic Search

    Sweat; J. R. Jr

    1979-01-01

    A system is described that provides potable hot water and that also provides heated air for heating enclosed spaces within buildings. The system consists of a water heater including a water tank filled with water, a burner for heating the water in the tank, and an exhaust flue for removing hot gases generated by the burner; a gas-to-liquid heat exchange

  12. A Water Recovery System Evolved for Exploration

    NASA Technical Reports Server (NTRS)

    ORourke, Mary Jane E.; Perry, Jay L.; Carter, Donald L.

    2006-01-01

    A new water recovery system designed towards fulfillment of NASA's Vision for Space Exploration is presented. This water recovery system is an evolution of the current state-of-the-art system. Through novel integration of proven technologies for air and water purification, this system promises to elevate existing technology to higher levels of optimization. The novel aspect of the system is twofold: Volatile organic contaminants will be removed from the cabin air via catalytic oxidation in the vapor phase, prior to their absorption into the aqueous phase, and vapor compression distillation technology will be used to process the condensate and hygiene waste streams in addition to the urine waste stream. Oxidation kinetics dictate that removal of volatile organic contaminants from the vapor phase is more efficient. Treatment of the various waste streams by VCD will reduce the load on the expendable ion exchange and adsorption media which follow, and on the aqueous-phase volatile removal assembly further downstream. Incorporating these advantages will reduce the weight, volume, and power requirements of the system, as well as resupply.

  13. The response of a bacterial biofilm community in a simulated industrial cooling water system to treatment with an anionic dispersant.

    PubMed

    MacDonald, R; Santa, M; Brözel, V S

    2000-08-01

    The effect of a dispersant on the microbial community in a simulated open recirculating cooling water system was determined by continuous operation of the system over two consecutive periods of 196 and 252 d, respectively. An open recirculating cooling water system feeding a modified Robbin's Device with synthetic cooling water to simulate the environment of an industrial cooling water system was set up. Planktonic and biofilm (mild steel and Nylon(R)) samples were taken weekly in 1997 (196-d period) and fortnightly in 1998 (252-d period). Each biofilm was scraped off and diluted in 10-ml 1 x phosphate-buffered saline (PBS). Serial dilutions were performed and plated onto R2A agar (pH 8.0) to obtain the predominant culturable bacteria. The diversity was determined by allocating groups according to colony morphology, diameter and colour. Diversity was calculated according to the Shannon-Weaver Index. During the first run (1997), dispersant was added on day 57 to a final concentration of 15 mg l-1 for 49 d, stopped for 49 d and dosed at 30 mg l-1 for 41 d. The second run entailed adding dispersant to a final concentration of 30 mg l-1 on day 98 for 70 d, stopping dosing for 56 d and resuming dosing at 30 mg l-1 for another 28 d. The 2-year evaluation period demonstrated that the biofilm-removing action of the dispersant decreased to a point where it was not effective at all. Our results showed that the synthetic dispersant evaluated was only effective initially, but was ineffective in controlling biofouling on Nylon, and to a lesser degree on mild steel at the recommended (15 mg l-1) as well as at double the recommended concentration in the long term. The release of cells from biofilms observed when dispersant dosing was terminated, supports the notion that a community attaching in the presence of the surface active agent was selected for. The decreased efficacy may therefore be due to a selection of strains able to remain attached and/or attach in the presence of the dispersant as demonstrated by shifts in the biofilm communities on both Nylon and mild steel. PMID:10971754

  14. AMTEC recirculating test cell component testing and operation

    NASA Astrophysics Data System (ADS)

    Underwood, M. L.; Sievers, R. K.; O'Connor, D.; Williams, R. M.; Jeffries-Nakamura, B.; Bankston, C. P.

    Alkali metal thermoelectric converter operation in a recirculating test cell (RTC), which requires a small electromagnetic pump (EM) and a high-temperature beta-double-prime alumina-solid-electrolyte (BASE)-to-metal seal, is discussed. The design of a pump and an active metal braze seal and the initial operation of a cell using these components are described. The pump delivered 0.25 cu cm/min against a 28-psia head. A braze seal system was selected after shear strength tests of Ta or Nb brazed to BASE by a variety of fillers including TiCuNi, TiNi, and TiNiCr. The TiCuNi filler was chosen for environment cell testing and showed no failure or observable degradation after short-term tests up to 1055 K. The pump and the Nb/TiCuNi/BASE seal were used in a test that demonstrated all the operational functions of the RTC for the first time. An increase in the radiation reduction factor at constant input power was observed, indicating that the condenser was being wet by sodium resulting in an increased reflectivity.

  15. Recent advances in AMTEC recirculating test cell performance

    NASA Astrophysics Data System (ADS)

    Underwood, Mark L.; Williams, Roger M.; Ryan, Margaret A.; Jeffries-Nakamura, Barbara; O'Connor, Dennis

    1993-01-01

    The alkali metal thermal to electric converter (AMTEC) is an electrochemical device for the direct conversion of thermal energy to electrical energy with efficiencies potentially near Carnot. The future usefulness of AMTEC for space power conversion depends on the efficiency of the devices. Systems studies have projected from 15% to 35% thermal to electric conversion efficiencies, and one experiment has demonstrated 19% efficiency for a short period of time. A recent experiment in a recirculating test cell (RCT) has demonstrated sustained conversion efficiencies as high as 13.2%. The cell was operated at lower current and 12% efficiency for over 1700 hours at the time of this writing. The cell required a maturation period of 355 hours at high temperature. During this period, the cell was operated once at 12% efficiency but was generally operated at lower powers. The maturation period ended with the formation of a reflective sodium film on the condenser surface which reduced the parasitic thermal losses in the cell. After maturation, the cell demonstrated the first experimental demonstration of the maximum efficiency occuring at a lower current than the maximum power. The cell also demonstrated an unexpected decrease in parasitic loss with increasing cell current. The decrease in parasitic loss resulted from the development of a more reflective sodium film at higher sodium fluxes.

  16. AMTEC recirculating test cell component testing and operation

    NASA Technical Reports Server (NTRS)

    Underwood, M. L.; Sievers, R. K.; O'Connor, D.; Williams, R. M.; Jeffries-Nakamura, B.; Bankston, C. P.

    1989-01-01

    Alkali metal thermoelectric converter operation in a recirculating test cell (RTC), which requires a small electromagnetic pump (EM) and a high-temperature beta-double-prime alumina-solid-electrolyte (BASE)-to-metal seal, is discussed. The design of a pump and an active metal braze seal and the initial operation of a cell using these components are described. The pump delivered 0.25 cu cm/min against a 28-psia head. A braze seal system was selected after shear strength tests of Ta or Nb brazed to BASE by a variety of fillers including TiCuNi, TiNi, and TiNiCr. The TiCuNi filler was chosen for environment cell testing and showed no failure or observable degradation after short-term tests up to 1055 K. The pump and the Nb/TiCuNi/BASE seal were used in a test that demonstrated all the operational functions of the RTC for the first time. An increase in the radiation reduction factor at constant input power was observed, indicating that the condenser was being wet by sodium resulting in an increased reflectivity.

  17. Recent advances in AMTEC recirculating test cell performance

    SciTech Connect

    Underwood, M.L.; Williams, R.M.; Ryan, M.A.; Jeffries-Nakamura, B.; O'Connor, D. (Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109 (United States))

    1993-01-15

    The alkali metal thermal to electric converter (AMTEC) is an electrochemical device for the direct conversion of thermal energy to electrical energy with efficiencies potentially near Carnot. The future usefulness of AMTEC for space power conversion depends on the efficiency of the devices. Systems studies have projected from 15% to 35% thermal to electric conversion efficiencies, and one experiment has demonstrated 19% efficiency for a short period of time. A recent experiment in a recirculating test cell (RCT) has demonstrated sustained conversion efficiencies as high as 13.2%. The cell was operated at lower current and 12% efficiency for over 1700 hours at the time of this writing. The cell required a maturation period of 355 hours at high temperature. During this period, the cell was operated once at 12% efficiency but was generally operated at lower powers. The maturation period ended with the formation of a reflective sodium film on the condenser surface which reduced the parasitic thermal losses in the cell. After maturation, the cell demonstrated the first experimental demonstration of the maximum efficiency occuring at a lower current than the maximum power. The cell also demonstrated an unexpected decrease in parasitic loss with increasing cell current. The decrease in parasitic loss resulted from the development of a more reflective sodium film at higher sodium fluxes.

  18. Water delivery in the Early Solar System

    E-print Network

    Dvorak, Rudolf; Süli, Áron; Sándor, Zsolt; Galiazzo, Mattia; Pilat-Lohinger, Elke

    2015-01-01

    As part of the national scientific network 'Pathways to Habitable Worlds' the delivery of water onto terrestrial planets is a key question since water is essential for the development of life as we know it. After summarizing the state of the art we show some first results of the transport of water in the early Solar System for scattered main belt objects. Hereby we investigate the questions whether planetesimals and planetesimal fragments which have gained considerable inclination due to the strong dynamical interactions in the main belt region around 2 AU can be efficient water transporting vessels. The Hungaria asteroid group is the best example that such scenarios are realistic. Assuming that the gas giants and the terrestrial planets are already formed, we monitor the collisions of scattered small bodies containing water (in the order of a few percent) with the terrestrial planets. Thus we are able to give a first estimate concerning the respective contribution of such bodies to the actual water content i...

  19. Determining the optimum solar water pumping system for domestic use, livestock water, or irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For several years we have field tested many different types of solar powered water pumping systems. In this paper, several steps are given to select a solar-PV water pumping system. The steps for selection of stand-alone water pumping system were: deciding whether a wind or solar water pumping sys...

  20. Developing Sustainable Spacecraft Water Management Systems

    NASA Technical Reports Server (NTRS)

    Thomas, Evan A.; Klaus, David M.

    2009-01-01

    It is well recognized that water handling systems used in a spacecraft are prone to failure caused by biofouling and mineral scaling, which can clog mechanical systems and degrade the performance of capillary-based technologies. Long duration spaceflight applications, such as extended stays at a Lunar Outpost or during a Mars transit mission, will increasingly benefit from hardware that is generally more robust and operationally sustainable overtime. This paper presents potential design and testing considerations for improving the reliability of water handling technologies for exploration spacecraft. Our application of interest is to devise a spacecraft wastewater management system wherein fouling can be accommodated by design attributes of the management hardware, rather than implementing some means of preventing its occurrence.