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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

Successful water reuse in open recirculating cooling systems  

SciTech Connect

Water reuse in open recirculating cooling water systems is becoming increasingly prevalent in industry. Reuse can incorporate a number of varied approaches with the primary goal being water conservation. Market forces driving this trend include scarcity of fresh water makeup sources and higher costs associated with pretreatment of natural waters. Utilization of reuse water for cooling tower makeup has especially detrimental effects on corrosion and deposit rates. Additionally, once the reuse water is cycled and treated with inhibitors, dispersants and microbiocides, acceptability for discharge to a public waterway can be a concern. The task for water treatment suppliers is to guide industry in the feasibility and procedures for successfully achieving these goals. This paper focuses particularly on reuse of municipal wastewater for cooling tower makeup and explores techniques which have been found especially effective. Case histories are described where these concepts have been successfully applied in practice.

Vaska, M.; Lee, B. [Drew Industrial Division, Boonton, NJ (United States)

1994-12-31

3

Technical Notes: Multiple-Tank Aquarium System with Recirculating Water for Laboratory Studies of Freshwater Fishes  

Microsoft Academic Search

A recirculating-water aquarium system for laboratory studies of freshwater fishes is described. The system consists of 216 glass tanks (3.5 gal each), two particle filters, a multistage biofilter, two ultraviolet-light sterilizers, and a regenerative blower for auxiliary aeration. Each tank is connected separately to the recirculating-water supply through inflow and outflow manifold pipes. Water flow to individual tanks is adjustable

Roger W. Rottmann; Donald E. Campton

1989-01-01

4

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

Microsoft Academic Search

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

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

2001-01-01

5

A design study on the optimal water refreshment rate in recirculating aquaculture systems  

Microsoft Academic Search

Refreshment (make-up) water is used in recirculating aquaculture systems (RAS) mainly to purge off-flavors, to add alkalinity and sometimes for temperature control. Alternatively, alkalinity may be added by means of a chemical base and heat may be supplied by a heating system. The objective of this study is to show how the optimal (minimizing cost) mix of the three controls:

Ido Seginer; Noam Mozes; Ori Lahav

2008-01-01

6

Improving Heating System Operations Using Water Re-Circulation  

E-print Network

. The adjustment formulas of the relative flow rate and temperatures of supply and return water for both primary and secondary circuits of the system are deduced. The corresponding adjustment curves are plotted with calculating examples. Analysis of the curves...

Li, F.; Han, J.

2006-01-01

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

Biofouling reduction in recirculating cooling systems through biofiltration of process water.  

PubMed

Biofouling is a serious problem in industrial recirculating cooling systems. It damages equipment, through biocorrosion, and causes clogging and increased energy consumption, through decreased heat transfer. In this research a fixed-bed biofilter was developed which removed assimilable organic carbon (AOC) from process water, thus limiting the major substrate for the growth of biofouling. The biofilter was tested in a laboratory model recirculating cooling water system, including a heat exchanger and a cooling tower. A second identical model system without a biofilter served as a reference. Both installations were challenged with organic carbon (sucrose and yeast extract) to provoke biofouling. The biofilter improved the quality of the recirculating cooling water by reducing the AOC content, the ATP concentration, bacterial numbers (30-40 fold) and the turbidity (OD660). The process of biofouling in the heat exchangers, the process water pipelines and the cooling towers, was monitored by protein increase, heat transfer resistance, and chlorine demanded for maintenance. This revealed that biofouling was lower in the system with the biofilter compared to the reference installation. It was concluded that AOC removal through biofiltration provides an attractive, environmental-friendly means to reduce biofouling in industrial cooling systems. PMID:12688686

Meesters, K P H; Van Groenestijn, J W; Gerritse, J

2003-02-01

9

Nitrification in brackish water recirculating aquaculture system integrated with activated packed bed bioreactor.  

PubMed

Recirculation aquaculture systems (RAS) depend on nitrifying biofilters for the maintenance of water quality, increased biosecurity and environmental sustainability. To satisfy these requirements a packed bed bioreactor (PBBR) activated with indigenous nitrifying bacterial consortia has been developed and commercialized for operation under different salinities for instant nitrification in shrimp and prawn hatchery systems. In the present study the nitrification efficiency of the bioreactor was tested in a laboratory level recirculating aquaculture system for the rearing of Penaeus monodon for a period of two months under higher feeding rates and no water exchange. Rapid setting up of nitrification was observed during the operation, as the volumetric total ammonia nitrogen removal rates (VTR) increased with total ammonia nitrogen (TAN) production in the system. The average Volumetric TAN Removal Rates (VTR) at the feeding rate of 160 g/day from 54-60th days of culture was 0.1533+/-0.0045 kg TAN/m(3)/day. The regression between VTR and TAN explained 86% variability in VTR (P<0.001). The laboratory level RAS demonstrated here showed high performance both in terms of shrimp biomass yield and nitrification and environmental quality maintenance. Fluorescent in-situ Hybridization analysis of the reactor biofilm ensured the presence of autotrophic nitrifier groups such as Nitrosococcus mobilis lineage, Nitrobacter spp and phylum Nitrospira, the constituent members present in the original consortia used for activating the reactors. This showed the stability of the consortia on long term operation. PMID:20150717

Rejish Kumar, V J; Joseph, Valsamma; Philip, Rosamma; Bright Singh, I S

2010-01-01

10

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

Microsoft Academic Search

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

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

11

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

Technology Transfer Automated Retrieval System (TEKTRAN)

Rainbow trout Oncorhynchus mykiss performance and water quality were evaluated and compared within six replicated 9.5 cubic meter water recirculating aquaculture systems (WRAS) operated with and without ozone at various water exchange rates. Three separate studies were conducted: 1) low water exchan...

12

Fish Health Management Considerations in Recirculating Aquaculture Systems -Part 1  

E-print Network

Cir 120 Fish Health Management Considerations in Recirculating Aquaculture Systems - Part 1, Tropical Aquaculture Laboratory, Ruskin FL 33570, Program in Fisheries and Aquatic Sciences, School Cooperating. Nick T. Place , Dean Introduction Recirculating aquaculture systems, also known as water reuse

Watson, Craig A.

13

Impact of water quality on the bacterial populations and off-flavours in recirculating aquaculture systems.  

PubMed

A variety of factors affecting water quality in recirculating aquaculture systems (RAS) are associated with the occurrence of off-flavours. In this study, we report the impact of water quality on the bacterial diversity and the occurrence of the geosmin-synthesis gene (geoA) in two RAS units operated for 252 days. Unit 2 displayed a higher level of turbidity and phosphate, which affected the fresh water quality compared with unit 1. In the biofilter, nitrification is one of the major processes by which high water quality is maintained. The bacterial population observed in the unit 1 biofilter was more stable throughout the experiment, with a higher level of nitrifying bacteria compared with the unit 2 biofilter. Geosmin appeared in fish flesh after 84 days in unit 2, whereas it appeared in unit 1 after 168 days, but at a much lower level. The geoA gene was detected in both units, 28 days prior to the detection of geosmin in fish flesh. In addition, we detected sequences associated with Sorangium and Nannocystis (Myxococcales): members of these genera are known to produce geosmin. These sequences were observed at an earlier time in unit 2 and at a higher level than in unit 1. This study confirms the advantages of new molecular methods to understand the occurrence of geosmin production in RAS. PMID:23228051

Auffret, Marc; Yergeau, Étienne; Pilote, Alexandre; Proulx, Émilie; Proulx, Daniel; Greer, Charles W; Vandenberg, Grant; Villemur, Richard

2013-05-01

14

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

PubMed

Fathead minnows (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. PMID:2331142

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

1990-01-01

15

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

SciTech Connect

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.

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

1990-01-01

16

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

Microsoft Academic Search

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

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

2010-01-01

17

Engine exhaust gas recirculation system  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine employs a recirculation control valve in a passageway connecting the engine exhaust passage to the engine intake passage downstream from the throttle valve. An air conduit having an air control valve therein furnishes atmospheric air to the intake passage downstream from the throttle valve. Vacuum responsive actuators are provided for

H. Nishimura; T. Shioya; T. Umemoto

1981-01-01

18

Is growth retardation present in Nile tilapia Oreochromis niloticus cultured in low water exchange recirculating aquaculture systems?  

Microsoft Academic Search

It has been suggested that fish cultured in recirculating aquaculture systems (RAS) grow less as compared with fish cultured in flow-through systems due to the accumulation of substances. In the Netherlands, the commercial culture of Nile tilapia Oreochromis niloticus in 300 and 600MT's systems is done exclusively in RAS operated at water exchange rates as low as 30L\\/kg feed\\/day due

Catarina I. M. Martins; Daniel Ochola; Stephan S. W. Ende; Ep H. Eding; Johan A. J. Verreth

2009-01-01

19

Combustion-gas recirculation system  

DOEpatents

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.

Baldwin, Darryl Dean (Lacon, IL)

2007-10-09

20

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

Microsoft Academic Search

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

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

2009-01-01

21

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

PubMed

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 Pco2. 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. PMID:25250476

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

2014-12-01

22

Solar heating systems for recirculation aquaculture  

Microsoft Academic Search

The literature over the past 25 years indicates that there has been a continued interest in using passive and active solar technologies to reduce the conventional energy required to maintain water temperatures in small recirculation aquaculture systems. Although all of the experimental systems reviewed report favourable results, there is little information available to guide system designers. This paper describes the

R. J. Fuller

2007-01-01

23

A practical application for the chemical treatment of Southern California`s reclaimed, Title 22 water for use as makeup water for recirculating cooling water systems  

SciTech Connect

Pilot cooling water studies conducted at a Southern California landfill/cogeneration station demonstrated a successful chemical treatment program for recirculating cooling water that used unnitrified, reclaimed, Title 22 water as the primary makeup water source. The constituents in the reclaimed water are supplied by variety of residential and waste water sources resulting in a water quality that may vary to a greater degree than domestic water supplies. This water contains high concentrations of orthophosphate, ammonia, chlorides and suspended solids. The impact of which, under cycled conditions is calcium orthophosphate scaling, high corrosion of yellow metal and mild steel, stress cracking of copper alloys and stainless steel and rapidly growing biological activity. A mobile cooling water testing laboratory with two pilot recirculating water systems modeled the cogeneration station`s cooling tower operating conditions and parameters. The tube and shell, tube side cooling heat exchangers were fitted with 443 admiralty, 90/10 copper nickel, 316 stainless steel and 1202 mild steel heat exchanger tubes. Coupons and Corrater electrodes were also installed. A chemical treatment program consisting of 60/40 AA/AMPS copolymer for scale, deposits and dispersion, sodium tolyltriazole for yellow metal corrosion, and a bromination program to control the biological activity was utilized in the pilot systems. Recirculating water orthophosphate concentrations reached levels of 70 mg/L as PO, and ammonia concentrations reached levels of 35 mg/L, as total NH3. The study successfully demonstrated a chemical treatment program to control scale and deposition, minimize admiralty, 90/10 copper nickel and carbon steel corrosion rates, prevent non-heat transfer yellow metal and stainless steel stress cracking, and control the biological activity in this high nutrient water.

Zakrzewski, J. [Calgon Corp., Pittsburgh, PA (United States); Cosulich, J.; Bartling, E. [County Sanitation Districts of Los Angeles County, Whittier, CA (United States)

1998-12-31

24

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...

25

Evaluation of ozonation on levels of the off-flavor compounds geosmin and 2-methylisoborneol in water and rainbow trout Oncorhynchus mykiss from water recirculation aquaculture systems  

Technology Transfer Automated Retrieval System (TEKTRAN)

Common “off-flavors” in fish cultured in water recirculation aquaculture systems (WRAS) are “earthy” and “musty” due to the presence of the off-flavor metabolites geosmin and 2-methylisoborneol (MIB), respectively. Previously, ozone addition has been applied to WRAS at relatively low doses to break...

26

The second-law analysis of a recirculation cycle desiccant cooling system: Cosorption of water vapor and carbon dioxide  

NASA Astrophysics Data System (ADS)

The second law, of thermodynamics is applied to a desiccant cooling system operating in the recirculation mode. In this study, the adsorbent is 13X molecular sieve, and the process air stream is assumed to contain only dry air, water vapor, and carbon dioxide. The second law efficiencies of a desiccant wheel are documented in terms of overall number of transfer units and the regeneration temperature. The results show that based on the first law and second law of thermodynamics, a solid desiccant adsorber using 13X molecular sieve can be optimally designed.

Shen, C. M.; Worek, W. M.

27

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...

28

Preoperational test report, recirculation condenser cooling systems  

SciTech Connect

This represents a preoperational test report for Recirculation Condenser Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The four system provide condenser cooling water for vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102. Each system consists of a valved piping loop, a pair of redundant recirculation pumps, a closed-loop evaporative cooling tower, and supporting instrumentation; equipment is located outside the farm on concrete slabs. Piping is routed to the each ventilation condenser inside the farm via below-grade concrete trenches. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

Clifton, F.T.

1997-11-04

29

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)

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.

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

1990-01-01

30

Pioneer colonizer microorganisms in biofilm formation on galvanized steel in a simulated recirculating cooling-water system.  

PubMed

Some bacteria have a higher tendency to produce biofilm than others. Especially, Pseudomonas and Aeromonas strains are acknowledged to be pioneer colonizers and are predominant in biofilm formation. We examined biofilm formation and first attachment maintance of biofilms of Pseudomonas spp., Pseudomonas aeruginosa, Aeromonas spp, sulphate reducing bacteria and filamentous fungi. A simulated recirculating cooling-water system was used. Heterotrophic bacteria counts on galvanized steel and glass surfaces rose during the tidy period of 720 hours. In addition, we determined that although Pseudomonas spp., Pseudomonas aeruginosa and Aeromonas spp. were the pioneer colonizers, they surprisingly could not be determined in the biofilms on both types of surface after 456 hours. Sulphate reducing bacteria were observed in biofilms on both surfaces from the outset of the experiments. Filamentous fungi were seen on the galvanized steel and glass surfaces after 0.5 h. PMID:19455520

Do?ruöz, Nihal; Göksay, Duygu; Ilhan-Sungur, Esra; Cotuk, Ay?in

2009-09-01

31

In-tank recirculating arsenic treatment system  

DOEpatents

A low-cost, water treatment system and method for reducing arsenic contamination in small community water storage tanks. Arsenic is removed by using a submersible pump, sitting at the bottom of the tank, which continuously recirculates (at a low flow rate) arsenic-contaminated water through an attached and enclosed filter bed containing arsenic-sorbing media. The pump and treatment column can be either placed inside the tank (In-Tank) by manually-lowering through an access hole, or attached to the outside of the tank (Out-of-Tank), for easy replacement of the sorption media.

Brady, Patrick V. (Albuquerque, NM); Dwyer, Brian P. (Albuquerque, NM); Krumhansl, James L. (Albuquerque, NM); Chwirka, Joseph D. (Tijeras, NM)

2009-04-07

32

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

33

Future of recirculating systems in the US aquaculture industry  

SciTech Connect

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.

Malone, R.F.

1994-08-01

34

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

SciTech Connect

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.

C. McGowin; M. DiFilippo; L. Weintraub

2006-06-30

35

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...

36

Use of Produced Water in Recirculating Cooling Systems at Power Generating Facilities  

SciTech Connect

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. This deliverable describes possible test configurations for produced water demonstration projects at SJGS. The ability to host demonstration projects would enable the testing and advancement of promising produced water treatment technologies. Testing is described for two scenarios: Scenario 1--PNM builds a produced water treatment system at SJGS and incorporates planned and future demonstration projects into the design of the system. Scenario 2--PNM forestalls or decides not to install a produced water treatment system and would either conduct limited testing at SJGS (produced water would have to be delivered by tanker trucked) or at a salt water disposal facility (SWD). Each scenario would accommodate demonstration projects differently and these differences are discussed in this deliverable. PNM will host a demonstration test of water-conserving cooling technology--Wet Surface Air Cooling (WSAC) using cooling tower blowdown from the existing SJGS Unit 3 tower--during the summer months of 2005. If successful, there may be follow-on testing using produced water. WSAC is discussed in this deliverable. Recall that Deliverable 4, Emerging Technology Testing, describes the pilot testing conducted at a salt water disposal facility (SWD) by the CeraMem Corporation. This filtration technology could be a candidate for future demonstration testing and is also discussed in this deliverable.

Kent Zammit; Michael N. DiFilippo

2005-07-01

37

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...

38

Geosmin and 2-Methylisoborneol Cause Off-Flavors in Cultured Largemouth Bass and White Sturgeon Reared in Recirculating-Water Systems  

Microsoft Academic Search

Earthy and musty off-flavors were present in the fillets of largemouth bass Micropterus salmoides and white sturgeon Acipenser transmontanus grown in partial water-recirculating aquaculture systems. Solid phase microextraction–gas chromatography–mass spectrometry revealed that geosmin and 2-methylisoborneol in the flesh of these fish caused these off-flavors.

Kevin K. Schrader; Sonia Acuña Rubio; Raul H. Piedrahita; Agnes M. Rimando

2005-01-01

39

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

Microsoft Academic Search

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)

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

1997-01-01

40

Processes to improve energy efficiency during pumping and aeration of recirculating water in circular tank systems  

Technology Transfer Automated Retrieval System (TEKTRAN)

Conventional gas transfer technologies for aquaculture systems occupy a large amount of space, require considerable capital investment, and can contribute to high electricity demand. In addition, diffused aeration in a circular tank can interfere with the hydrodynamics of water rotation and the spee...

41

The effect of recirculating aquaculture systems on the concentrations of heavy metals in culture water and tissues of Nile tilapia Oreochromis niloticus  

Microsoft Academic Search

To date, farming fish in recirculating aquaculture systems (RAS) is one of the most environmentally friendly ways of producing fish. However, with the trend towards intensification, and consequently decrease in water exchange rates, these systems may accumulate substances, such as heavy metals, in the water and fish. Inductively-coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectroscope (ICP-MS) were used

Catarina I. M. Martins; Ep H. Eding; Johan A. J. Verreth

2011-01-01

42

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

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.

Ally, M.R.

2002-11-14

43

Principles of Water Recirculation and Filtration in Aquaculture 1  

E-print Network

FA12 Principles of Water Recirculation and Filtration in Aquaculture 1 Michael McGee and Charles McGee, former assistant professor and extension aquaculture specialist, and Charles Cichra, associate culture units. These systems have practical applications in commercial aquaculture hatcheries, holding

Watson, Craig A.

44

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

SciTech Connect

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.

Michael N. DiFilippo

2004-08-01

45

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

SciTech Connect

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.

Michael N. DiFilippo

2004-08-01

46

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

SciTech Connect

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.

Kent Zammit; Michael N. DiFilippo

2005-01-01

47

Nitrite-oxidizing bacteria, Nitrospira, distribution in the outer layer of the biofilm from filter materials of a recirculating water system for the goldfish Carassius auratus  

Microsoft Academic Search

We used a clone library method to investigate changes in the biofilm microflora associated with the conditioning of filter materials in a recirculating water system for the culture of goldfish Carassius auratus. The microbial density was higher in the outer layer of biofilm from filter materials (1.7×1010–3.0×1010 cells\\/g) than in the inner layer (1.5×109–2.4×109 cells\\/g) throughout the experimental period. The clone library

Shiro Itoi; Noriaki Ebihara; Sayaka Washio; Haruo Sugita

2007-01-01

48

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...

49

Effect of CaCO? particles and suspended bacteria on biofilm components and activity in the model recirculating cooling water system.  

PubMed

Biofilms are a serious problem in industrial recirculating cooling water systems. Biofilm formation and properties are affected by many factors, such as inorganic particles and suspended bacteria. In this research a laboratory model recirculating cooling water system was applied to investigate the effects of CaCO(3) concentration and suspended bacterial count on extracellular polymeric substances (EPS) content and dehydrogenase activity (DHA) in the attached biofilms. In addition, nutrient level was also the key factor when investigating the effect of suspended bacterial count. The results showed that EPS content and DHA first increased and then decreased with the increase of CaCO(3) concentration from 0 to 200 mg/l. At the low nutrient level, with the increase of suspended bacterial count from 4.04 to 5.78 log(10) c.f.u./ml, biofilm EPS content decreased firstly and then increased. However, biofilm DHA always gradually increased. At the medium nutrient level, biofilm EPS content increased firstly and then decreased and DHA always gradually decreased when suspended bacterial count ranged from 4.04 to 5.78 log(10) c.f.u./ml. At the high nutrient level, biofilm EPS content and DHA both showed the increasing trend with the increase of suspended bacterial count. This work provides the basis and reference for management strategies in actual recirculating cooling water systems. PMID:22805808

Liu, Fang; Dong, Wenwen; Yang, Fei; Lu, Lei; Wang, Yongqiang; Yin, Xiaochen; Zhao, Chaocheng

2012-03-01

50

Exhaust gas recirculation control system  

Microsoft Academic Search

A control valve in an exhaust gas recirculation line for an engine is operated by vacuum pressure from a regulating valve. The regulating valve has a vacuum chamber positioned between two orifices mounted in a line leading to atmospheric air intake. An air valve located downstream from said regulating valve and orifices controls vacuum pressure from a control suction air

M. Kawamoto; Y. Otobe

1983-01-01

51

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

NASA Technical Reports Server (NTRS)

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.

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

2014-01-01

52

Hydrothermal carbonization: process water characterization and effects of water recirculation.  

PubMed

Poplar wood chips were treated hydrothermally and the increase of process efficiency by water recirculation was examined. About 15% of the carbon in the biomass was dissolved in the liquid phase when biomass was treated in de-ionized water at 220 °C for 4 h. The dissolved organic matter contained oxygen and was partly aerobically biodegradable. About 30-50% of the total organic carbon originated from organic acids. A polar and aromatic fraction was extracted and a major portion of the organic load was of higher molecular weight. By process water recirculation organic acids in the liquid phase concentrated and catalyzed dehydration reactions. As a consequence, functional groups in hydrothermally synthesized coal declined and dewaterability was enhanced. Recirculated reactive substances polymerized and formed additional solid substance. As a result, carbon and energetic yields of the produced coal rose to 84% and 82%, respectively. PMID:23792664

Stemann, Jan; Putschew, Anke; Ziegler, Felix

2013-09-01

53

Impact of water boundary layer diffusion on the nitrification rate of submerged biofilter elements from a recirculating aquaculture system.  

PubMed

Total ammonia nitrogen (TAN) removal by microbial nitrification is an essential process in recirculating aquaculture systems (RAS). In order to protect the aquatic environment and fish health, it is important to be able to predict the nitrification rates in RAS's. The aim of this study was to determine the impact of hydraulic film diffusion on the nitrification rate in a submerged biofilter. Using an experimental batch reactor setup with recirculation, active nitrifying biofilter units from a RAS were exposed to a range of hydraulic flow velocities. Corresponding nitrification rates were measured following ammonium chloride, NH?Cl, spikes and the impact of hydraulic film diffusion was quantified. The nitrification performance of the tested biofilter could be significantly increased by increasing the hydraulic flow velocity in the filter. Area based first order nitrification rate constants ranged from 0.065 m d?¹ to 0.192 m d?¹ for flow velocities between 2.5 m h?¹ and 40 m h?¹ (18 °C). This study documents that hydraulic film diffusion may have a significant impact on the nitrification rate in fixed film biofilters with geometry and hydraulic flows corresponding to our experimental RAS biofilters. The results may thus have practical implications in relation to the design, operational strategy of RAS biofilters and how to optimize TAN removal in fixed film biofilter systems. PMID:22507250

Prehn, Jonas; Waul, Christopher K; Pedersen, Lars-Flemming; Arvin, Erik

2012-07-01

54

Rating fixed film nitrifying biofilters used in recirculating aquaculture systems  

Microsoft Academic Search

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

Ronald F. Malone; Timothy J. Pfeiffer

2006-01-01

55

Design of a computerized, temperature-controlled, recirculating aquaria system  

E-print Network

Design of a computerized, temperature-controlled, recirculating aquaria system Ann M. Widmer temperature control to maintain static temperatures, increase temperatures 1 8C/day, and maintain diel in fish tanks to a desired set temperature and then calculated the amount of hot or cold water to add

Bonar, Scott A.

56

Production of cobia in recirculating systems  

Technology Transfer Automated Retrieval System (TEKTRAN)

Only limited information exists with respect to rearing juvenile cobia Rachycentron canadum to stocker and marketable sizes using recirculating aquaculture systems (RAS). To investigate this topic, two rearing trials were conducted using commercial scale RAS. In Trial 1, juvenile cobia (29 g) we...

57

Common carp (Cyprinus carpio) response to two pieces of music ("Eine Kleine Nachtmusik" and "Romanza") combined with light intensity, using recirculating water system.  

PubMed

The objective of this study was to further investigate the effects of music on fish physiology, bearing in mind available information regarding the involvement of endogenous and exogenous factors in fish farming. Therefore, Cyprinus carpio (50.5 +/- 0.36 g) were reared in a recirculating water system under 80 and 200 lux and subjected to no music at all (control, ambient noise only), 4 h of Mozart's "Eine Kleine Nachtmusik", or 4 h of anonymous "Romanza-Jeux Interdits" for 106 days. Both music treatments resulted in increased growth performance at both light intensities, with Romanza treatment at 200 lux resulting in better growth performance than Mozart treatment. Furthermore, feed efficiency for the Romanza groups was significantly better than for the control. Although no significant music effect was apparent for brain neurotransmitters, lower anterior intestine alkaline protease levels were detected for both music treatments. Taking into consideration the numerous advantages of recirculating water systems, it should be emphasised that fish response to music expresses the results of various physiological and biochemical processes, especially when fish notably respond differently when subjected to two different pieces of music. PMID:19408132

Papoutsoglou, Sofronios E; Karakatsouli, Nafsika; Papoutsoglou, Eustratios S; Vasilikos, Georgios

2010-09-01

58

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

Microsoft Academic Search

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

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

2007-01-01

59

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

Microsoft Academic Search

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

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

2003-01-01

60

Diesel emission control system using combined process of nonthermal plasma and exhaust gas components' recirculation  

Microsoft Academic Search

A NOx aftertreatment system, using nonthermal plasma (NTP) reduction and exhaust gas components' recirculation, is investigated. A pilot-scale system is applied to a stationary diesel engine. In this system, NOx is first removed by adsorption, and subsequently, the adsorbent is regenerated by thermal desorption. NOx desorbed is reduced by using nitrogen NTP. Moreover, NOx, CO2, and water vapor recirculated into

Keiichiro Yoshida; Tomoyuki Kuroki; Masaaki Okubo

2009-01-01

61

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

E-print Network

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

Watson, Craig A.

62

Exhaust gas recirculation system for internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine is disclosed that has an exhaust gas recirculation passage, a constant pressure chamber disposed at an intermediate portion of the exhaust gas recirculation passage, a pressure regulating valve operative in response to the exhaust gas pressure in the constant pressure chamber, a first flow-rate control valve actuated by vacuum regulated

Y. Ikuta; M. Matsuo

1981-01-01

63

Exhaust gas recirculation system for internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine has an exhaust gas recirculation passage, a constant pressure chamber disposed in the exhaust gas recirculation passage, a pressure regulating valve operative in response to the exhaust gas pressure in the constant pressure chamber, a first flow-rate control valve adapted to be actuated by the vacuum regulated by the pressure

Y. Ikuta; M. Matsuo

1981-01-01

64

2-Methylisoborneol and geosmin uptake by organic sludge derived from a recirculating aquaculture system  

Microsoft Academic Search

In a previous study on a recirculating fish culture system, levels of geosmin and 2-methylisoborneol were found to decrease when culture water was recirculated through the anaerobic sludge digestion treatment stage of the system. This finding led us to the present study in which the geosmin and 2-methylisoborneol removal capacity of the sludge derived from this treatment stage was examined

Lior Guttman; Jaap van Rijn

2009-01-01

65

Developments in recirculating systems for Arctic char culture in North America  

Microsoft Academic Search

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

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

2004-01-01

66

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

NASA Technical Reports Server (NTRS)

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.

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

2014-01-01

67

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

NASA Technical Reports Server (NTRS)

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.

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

2014-01-01

68

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...

69

Exhaust gas recirculation regulating system  

Microsoft Academic Search

A system for controlling introduction of gas into a passage of an internal combustion engine employs a first control valve in a gas introduction passageway, a second control valve in an air conduit connecting the intake passage to atmosphere, and a regulating valve responsive to vacuum intensity in the intake passage. The regulating valve actuates vacuum responsive actuators for the

K. Ishii; T. Shioya

1980-01-01

70

Integrated Dynamic Aquaculture and Wastewater Treatment Modelling for Recirculating Aquaculture Systems  

Microsoft Academic Search

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

Torsten E. I. Wika; Bjorn T. Lind

71

Integrated dynamic aquaculture and wastewater treatment modelling for recirculating aquaculture systems  

Microsoft Academic Search

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

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

2009-01-01

72

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

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

David Dzombak; Radisav Vidic; Amy Landis

2012-06-30

73

Exhaust gas recirculation system for an internal combustion engine  

DOEpatents

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.

Wu, Ko-Jen

2013-05-21

74

Foam fractionation efficiency in particulate matter and heterotrophic bacteria removal from a recirculating seabass ( Dicentrarchus labrax) system  

Microsoft Academic Search

In recirculating aquaculture systems (RAS), particulate matter and bacterial communities management are required to maintain water quality. Foam fractionation is a water treatment technology that can be easily applied to water reuse systems to remove bacteria and suspended solids. This study investigated the efficiency of foam fractionation in removing particulate matter and heterotrophic bacteria in a closed recirculating seabass (Dicentrarchus.

Fabio Brambilla; Micaela Antonini; Pietro Ceccuzzi; Genciana Terova; Marco Saroglia

2008-01-01

75

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...

76

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...

77

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

Microsoft Academic Search

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

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

2009-01-01

78

Evaluation of ozonation on levels of the off-flavor compounds geosmin and 2-methylisoborneol in water and rainbow trout Oncorhynchus mykiss from recirculating aquaculture systems  

Microsoft Academic Search

Common “off-flavors” in fish cultured in recirculating aquaculture systems (RAS) are “earthy” and “musty” due to the presence of the off-flavor metabolites geosmin and 2-methylisoborneol (MIB), respectively. Previously, ozone addition has been applied to RAS at relatively low doses to break refractory organic molecules (i.e., reducing color), microflocculate fine particulate matter (i.e., increasing solids removal), and oxidize nitrite to nitrate,

Kevin K. Schrader; John W. Davidson; Agnes M. Rimando; Steven T. Summerfelt

2010-01-01

79

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

Microsoft Academic Search

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

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

2011-01-01

80

The design and construction of an open channel recirculating water tank for the study of biological hydrocarbons  

E-print Network

This project chronicles the design and construction of a small scale recirculating water tank for the purpose of studying biological hydrodynamics. Currently available systems were analyzed and studied prior to developing ...

Hennessey, Thomas V. (Thomas Vincent), III

2005-01-01

81

Continuous hydroponic wheat production using a recirculating system  

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

82

Nutrient removal from aquaculture wastewater by vegetable production in aquaponics recirculation system  

Microsoft Academic Search

Nutrient removal is essential for aquaculture wastewater treatment to protect receiving water from eutrophication and for potential reuse of the treated water. The integration of aquaculture with agriculture appears to be an excellent way of saving water, disposing aquaculture wastewater and providing fertilizer to the agricultural crop. The study was conducted to evaluate aquaponics recirculation system (ARS) performance in removing

A. Enduta; A. Jusoh; N. Ali; W. B. Wan Nik

2011-01-01

83

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

84

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

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

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

2006-01-01

85

The potential for integrated biological treatment systems in recirculating fish culture-A review  

Microsoft Academic Search

Intensive aquaculture in recirculating systems is rapidly developing, and with it arises the need for reliable treatment systems. To enable reuse of water in these systems, biological treatment is considered the most economically feasible approach. In this review the advantages and disadvan- tages of some of the most commonly used biological treatment systems are examined. Using as a comparator the

Jaap van Rijn

86

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

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

87

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

Microsoft Academic Search

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

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

2010-01-01

88

Recirculating gas stripper system for 15 UD Pelletron  

NASA Astrophysics Data System (ADS)

A new recirculating turbo molecular pump-based gas stripper system has been designed and installed in the high-voltage terminal of the 15 UD pelletron. The system has been installed as a part of the Accelerator Mass Spectrometry facility development program and is being used for regular accelerator operation. The vacuum inside the accelerator during gas strip has improved considerably. Beam transmission through the accelerating column is increased. The system is performing satisfactorily. The design and performance of the gas recirculating system is presented.

Chopra, S.; Pawar, N. S.; Singh, M. P.; Kumar, Rakesh; Prasad, J.; Patel, V. P.; Pal, Raj; Sota, M.; Devarani, K.; Ojha, S.; Gargari, S.; Joshi, R.; Kanjilal, D.; Datta, S. K.

2005-09-01

89

Evaluación de algunos parámetros de calidad del agua en un sistema cerrado de recirculación para la acuicultura, sometido a diferentes cargas de biomasa de peces Evaluation of some water quality parameters in a closed aquaculture recirculating-water system, submitted to diferent loads of fish  

Microsoft Academic Search

Utilizing different loadings of biomass of the Nile Tilapia Oreochromis niloticus and rainbow trout Oncorhynchus mykiss, some water quality parameters were evaluated in a closed aquaculture recirculating system. The systems is integrated by six culture tanks, a sedimentation cistern, two submerged bio-filters, a fast sand filter,

Genoveva Ingle de la Mora; Enrique L. Villareal-Delgado; José L. Arredondo-Figueroa; Jesús T. Ponce-Palafox; A. Barriga-Sos

2003-01-01

90

New developments in recirculating aquaculture systems in Europe: A perspective on environmental sustainability  

Microsoft Academic Search

The dual objective of sustainable aquaculture, i.e., to produce food while sustaining natural resources is achieved only when production systems with a minimum ecological impact are used. Recirculating aquaculture systems (RASs) provide opportunities to reduce water usage and to improve waste management and nutrient recycling. RAS makes intensive fish production compatible with environmental sustainability. This review aims to summarize the

C. I. M. Martins; E. H. Eding; M. C. J. Verdegem; L. T. N. Heinsbroek; O. Schneider; J. P. Blancheton; E. Roque d’Orbcastel; J. A. J. Verreth

2010-01-01

91

Growth and survival of juvenile cobia, Rachycentron canadum, at different salinities in a recirculating aquaculture system  

Microsoft Academic Search

Cobia (Rachycentron canadum) is an emerging aquaculture candidate for both offshore cage culture and land-based systems such as recirculating aquaculture systems. The ability to grow cobia at salinities other than oceanic (?34 ppt) could present culturists with additional production opportunities with this species. Culture at low salinities could also reduce the incidence of disease and simplify water management. In two

Matthew J. Resley; Kenneth A. Webb; G. Joan Holt

2006-01-01

92

The accumulation of substances in Recirculating Aquaculture Systems (RAS) affects embryonic and larval development in common carp Cyprinus carpio  

Microsoft Academic Search

The accumulation of substances in Recirculating Aquaculture Systems (RAS) may impair the growth and welfare of fish. To test the severity of contaminants accumulated in RAS, early-life stages of fish were used. Ultrafiltered water from two Recirculating Aquaculture Systems (RAS), one RAS with a high accumulation of substances (water exchange rate 30 L\\/kg feed\\/day) and one RAS with a low accumulation

Catarina I. M. Martins; Marco G. Pistrin; Stephan S. W. Ende; Ep H. Eding; Johan A. J. Verreth

2009-01-01

93

Exergetic performance analysis of a recirculating aquaculture system  

Microsoft Academic Search

This paper examines exergetic aspects of a Recirculation Aquaculture System (RAS) for Black Sea trout (Salmo trutta labrax) fingerling rearing at the Trabzon Central Fisheries Research Institute, Turkey. In its thermodynamic analysis, each component of the RAS is treated as a steady-state steady flow system and its exergetic efficiencies are studied. In addition, the following parameters are measured and recorded

Haydar Kucuk; Adnan Midilli; Atilla Özdemir; Eyüp Çakmak; Ibrahim Dincer

2010-01-01

94

Ozone Application in Recirculating Aquaculture System: An Overview  

Microsoft Academic Search

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

Alex Augusto Gonçalves; Graham A. Gagnon

2011-01-01

95

Exhaust gas recirculation system of a motor vehicle  

Microsoft Academic Search

An improvement for an exhaust gas recirculation (EGR) system of a motor vehicle is described. The system consists of: (1) a diaphragm type EGR valve mounted on an EGR pipe which connects the exhaust manifold and the intake manifold; (2) an opening path for air from the atmosphere diverged from a connecting pipe which connects the diaphragm chamber of the

Hamanishi

1977-01-01

96

An Inexpensive Recirculating Aquaculture System with Multiple Use Capabilities.  

ERIC Educational Resources Information Center

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)

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

1999-01-01

97

A conceptual, stoichiometry-based model for single-sludge denitrification in recirculating aquaculture systems  

Microsoft Academic Search

In the near future, the discharge of nitrate from recirculating aquaculture systems (RAS) to receiving water bodies is expected to be constrained by environmental regulations. Following wastewater treatment terminology, nitrate removal that makes use of the organic solid wastes generated within the RAS as the energy source for denitrification, may be termed ‘single-sludge denitrification’. In this approach, the costs associated

Sivan Klas; Noam Mozes; Ori Lahav

2006-01-01

98

????????????????????????????????????????????????????????????????????????????????????? CULTIVATION OF BABYLONIA SNAIL LARVAE USING CLOSED RECIRCULATING SEAWATER SYSTEM WITH SEMI-CONTINUOUS ALGAL PRODUCTION  

Microsoft Academic Search

With this study, veliger larvae of Babylonia snail (marine gastropod) were reared in the recirculating aquaculture system (RAS) in comparison with control tank with water exchange. The RAS consisted of five components including (1) algal photobioreactor, (2) Babylonia larviculture tank, (3) fluidizing biofilter tank, (4) sedimentation tank, and (5) algal medium preparation tank. Liquid culture of the microalga (Isochrysis galbana)

Yuwadee Aunthasoot; Chansawang Ngamphongsai; Seri Donnua; Sorawit Powtongsook; Ninnaj Chaitanawisuti; Somkiat Piyatiratitivorakul

99

Membrane Filtration Coupled with Chemical Precipitation to Treat Recirculating Aquaculture System Effluents  

Microsoft Academic Search

Effluents from recirculating aquaculture systems (RAS) contain high concentrations of nitrogen and phosphorous wastes and thus of- ten require proper treatment to prevent potential detrimental impacts on receiving water bodies. The purpose of this study was to evaluate the feasibility of membrane filtration coupled with chemical precip- itation as a pretreatment step with emphasis on phosphorus removal from RAS effluents.

Ling Yang; Hongde Zhou; Richard Moccia

2006-01-01

100

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...

101

Researchers evaluate low-energy recirculating system for inland production of marine finfish juveniles  

Technology Transfer Automated Retrieval System (TEKTRAN)

The low-energy recirculating aquaculture system consists of nine separate modules which utilize the double drain fish culture tank paired to a moving bed biofilter. The nine fiberglass tanks are five feet in diameter and normal water depth is about three feet for a total tank volume of approximately...

102

Design of a computerized, temperature-controlled, recirculating aquaria system  

USGS Publications Warehouse

We built a recirculating aquaria system with computerized temperature control to maintain static temperatures, increase temperatures 1 ??C/day, and maintain diel temperature fluctuations up to 10 ??C. A LabVIEW program compared the temperature recorded by thermocouples in fish tanks to a desired set temperature and then calculated the amount of hot or cold water to add to tanks to reach or maintain the desired temperature. Intellifaucet?? three-way mixing valves controlled temperature of the input water and ensured that all fish tanks had the same turnover rate. The system was analyzed over a period of 50 days and was fully functional for 96% of that time. Six different temperature treatments were run simultaneously in 18, 72 L fish tanks and temperatures stayed within 0.5 ??C of set temperature. We used the system to determine the upper temperature tolerance of fishes, but it could be used in aquaculture, ecological studies, or other aquatic work where temperature control is required. ?? 2005 Elsevier B.V. All rights reserved.

Widmer, A.M.; Carveth, C.J.; Keffler, J.W.; Bonar, Scott A.

2006-01-01

103

Powdered activated carbon for fouling reduction of a membrane in a pilot-scale recirculating aquaculture system  

Microsoft Academic Search

Recirculating aquaculture systems (RAS) are essential for the reduction in fresh water usage as well as the discharge of nutrients along with aquaculture effluents. A RAS consisting of an anoxic reactor, a membrane bioreactor (MBR) and a UV-disinfection unit was used to process 10,000 L\\/d of aquaculture effluent providing high-quality treated water for recirculation to a Barramundi fish culture. The

V. Jegatheesan; N. Senaratne; C. Steicke; Seung-Hyun Kim

2009-01-01

104

Anaerobic digestion of sludge from intensive recirculating aquaculture systems: Review  

Microsoft Academic Search

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

Natella Mirzoyan; Yossi Tal; Amit Gross

2010-01-01

105

Recirculating Liquid Nitrogen System for Operation of Cryogenic Pumps  

E-print Network

1 Recirculating Liquid Nitrogen System for Operation of Cryogenic Pumps IEPC-2011-217 Presented on propellant gases of interest. Cryopumps utilize a liquid nitrogen- cooled radiation shroud to allow cryogenerators to reliquify nitrogen gas removes the cost of LN2 from cryopump operations. The High- Power

Walker, Mitchell

106

Vacuum regulation valve in an exhaust gas recirculation system  

Microsoft Academic Search

The vacuum regulation valve operable to regulate the vacuum in the vacuum line of an exhaust gas recirculation system, includes a compact construction and a buffer means which is effective to eliminate the clattering sounds inherent in the conventional vacuum regulation valve.

M. Washio; T. Harada

1978-01-01

107

Potential and limitations of ozone for the removal of ammonia, nitrite, and yellow substances in marine recirculating aquaculture systems  

Microsoft Academic Search

The high levels of water-reuse in intensive recirculating aquaculture systems (RAS) require an effective water treatment in order to maintain good water quality. In order to reveal the potential and limitations of ozonation for water quality improvement in marine RAS, we tested ozone's ability to remove nitrite, ammonia, yellow substances and total bacterial biomass in seawater, considering aspects such as

J. P. Schroeder; P. L. Croot; B. Von Dewitz; U. Waller; R. Hanel

2011-01-01

108

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

PubMed

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

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

2011-01-01

109

DETERMINATION OF THE SOLIDS REMOVAL EFFICIENCY FOR SYSTEM COMPONENTS IN A RECIRCULATING AQUACULTURE SYSTEM USING PARTICLE SIEVE ANALYSIS  

Technology Transfer Automated Retrieval System (TEKTRAN)

A major target in the recirculating water treatment scheme of an aquaculture production system is removal of suspended solids. The large volumes of waste fish generate are highly organic in nature and contribute to filter clogging, ammonia production, oxygen consumption, and disease for systems empl...

110

Ammonia Conversion Characteristics in a Closed Recirculating Aquaculture System  

Microsoft Academic Search

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

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

2009-01-01

111

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

Microsoft Academic Search

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).

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

2010-01-01

112

Equipment review: The molecular adsorbents recirculating system (MARS®)  

Microsoft Academic Search

The molecular adsorbents recirculating system (MARS®) is a form of artificial liver support that has the potential to remove substantial quantities of albumin-bound toxins that have been postulated to contribute to the pathogenesis of liver cell damage, haemodynamic instability and multi-organ failure in patients with acute liver failure (ALF) and acute-on-chronic liver failure (AoCLF). These toxins include fatty acids, bile

Martin Boyle; Jelica Kurtovic; David Bihari; Stephen Riordan; Christian Steiner

2004-01-01

113

Photocatalytic reactors for treating water pollution with solar illumination: A simplified analysis for n-steps flow reactors with recirculation  

Microsoft Academic Search

The concentration of dissolved oxygen in water, in equilibrium with atmospheric air (ca. 8ppm at 20°C), defines the limits of all practical oxidizing processes for removing pollutants in photocatalytic reactors. To solve this limitation, an alternative approach to that of a continuously aerated reactor is the use of a recirculating system with aeration performed after every cycle at the reactor

Gerd Sagawe; Rodolfo J. Brandi; Detlef Bahnemann; Alberto E. Cassano

2005-01-01

114

Low-Dose Hydrogen Peroxide Application in Closed Recirculating Aquaculture Systems  

Microsoft Academic Search

The aim of the present work was to simulate water treatment practices with hydrogen peroxide (HP) in recirculating aquaculture systems (RAS). Six identical 1,700-L pilot-scale RAS were divided into two experimental groups based on daily feed allocation and operated under constant conditions for a period of 3 months. The organic and nitrogenous loadings of the systems differed fourfold between the

Lars-Flemming Pedersen; Christopher M. Good; Per B. Pedersen

2012-01-01

115

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

E-print Network

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

Gross, Amit

116

Evaluation of larval hybrid striped bass Morone chrysops x M. saxatilis growth under three different dietary feeding regimes in two recirculating tank systems: Green water vs. clear water  

Technology Transfer Automated Retrieval System (TEKTRAN)

Optimizing growth of larval hybrid striped bass (HSB) in closed tank systems is important because it allows for more environmental control and predictable production of feed trained fingerlings that do not rely on seasonal variation nor pond blooms. The purpose of this study was to further optimize ...

117

CONTRIBUTIONS TO THE KNOWLEDGEMENT OF THE GROWTH TECHNOLOGY OF ONCORHYNCHUS MYKISS SPECIES IN RECIRCULATING AQUACULTURAL SYSTEM CONTRIBU ?II LA CUNOATEREA TEHNOLOGIEI DE CRETERE A SPECIEI ONCORHYNCHUS MYKISS ÎN SISTEM RECIRCULANT  

Microsoft Academic Search

A Recirculating Aquacultural System (RAS) can be de fined as an aquacultural system that incorporates the treatment and reuse of water with less than 10% of the total water volume replaced per day and in which th e environmental conditions are being controlled. The concept of RAS is to reuse a volume of water through continuous treatment. The research was

ANI ALINA RODICA

118

Recyclotron III, a recirculating plasma fusion system  

SciTech Connect

This patent describes a recyclotron nuclear fusion system comprising recyclotrons. Each recyclotron comprises cyclotron means for receiving and accelerating charged particles in spiral and work conservative pathways. An output means forms a beam from particles received from the cyclotron means; (i) the cyclotron means comprising (a) a channel shaped electromagnet having a pair of indented polefaces, oriented along an input axis and defining an input axis and defining an input magnetic well, (b) a pair of elongated linear electrodes centered along the input magnetic well arranged generally parallel to the input axis and having a gap therebetween, (c) tuned oscillator means connected to the electrodes for applying an oscillating electric potential thereto, (ii) the output means comprising (e) inverter means comprising an electromagnet having a polarity opposite that of the channel shaped electromagnet oriented contigously therealong for extracting fully accelerated particles from the cyclotron means, and (f) reinverter means comprising an electromagnet having a polarity the same as that of the channel shaped electromagnet for correcting the flightpath of the extracted particles.

Jarnagin, W.S.

1987-01-27

119

Characterization of a biofilm bacterium from a recirculation system for European lobster ( Homarus gammarus)  

Microsoft Academic Search

The European lobster (Homarus gammarus) is often stored live in re-circulation systems. Previously bio-films and fouling has been reported to occur during storage of live aquatic animals. This investigation profiled a bacterium isolated from a bio-film observed on the carapace of live lobster and on the sub-water surfaces of the holding facility. Molecular analysis using a universal 16s rRNA primer

Jennifer E. Welsh; Pauline A. King; Eugene MacCarthy

2011-01-01

120

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

Microsoft Academic Search

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

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

2001-01-01

121

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

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

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

2012-01-01

122

Evaluation of the impact of nitrate-nitrogen levels in recirculating aquaculture systems on concentrations of the off-flavor compounds geosmin and 2-methylisoborneol in water and rainbow trout (Oncorhynchus mykiss)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Aquatic animals raised in recirculating aquaculture systems (RAS) can develop preharvest “off-flavors” such as “earthy” or “musty” which are caused by the bioaccumulation of the odorous compounds geosmin or 2-methylisoborneol (MIB), respectively, in their flesh. Tainted aquatic products cause large...

123

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

Microsoft Academic Search

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

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

2008-01-01

124

Microbial diversity of biological filters in recirculating aquaculture systems.  

PubMed

Development of environmentally sustainable farming of marine and freshwater species using recirculating aquaculture systems (RASs) requires a complete understanding of the biological component involved in wastewater treatment. This component integrates biofilters composed of microbial communities whose structure, dynamics, and activities are responsible for system success. Engineering highly efficient, environmentally sound, disease-free, and economically viable systems necessitates a thorough knowledge of microbial processes involved in all facets of RAS biofilters and has only recently been the focus of comprehensive studies. These studies have included the application of molecular tools to characterize community diversity and have identified key processes useful for improving system performance. In this paper we summarize the current understanding of the microbial diversity and physiology of RAS biofilters and discuss directions for future studies. PMID:20371171

Schreier, Harold J; Mirzoyan, Natella; Saito, Keiko

2010-06-01

125

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

PubMed

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

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

2003-01-01

126

NITRIFICATION PERFORMANCE OF A PROPELLER-WASHED BEAD CLARIFIER SUPPORTING A FLUIDIZED SAND BIOFILTER IN A RECIRCULATING WARMWATER FISH SYSTEM  

Technology Transfer Automated Retrieval System (TEKTRAN)

A propeller-wash bead filter (PWBF) and a fluidized sand filter (FSF) on a 28 m3 recirculating system stocked with tilapia maintained favorable water quality at five different feed rates, ranging from 0.9 to 4.5 kg feed per day. TAN removal rates ranged up to about 200 g TAN per m3 of media per day ...

127

Handheld recirculation system and customized media for microfluidic cell culture.  

PubMed

A palm-sized microfluidic recirculation system and customized media enable simplified long-term culture and imaging of cells. The combination of bare Braille display modules, a leveled monolithic surface for complete chip mounting, and a transparent heater improved portability, mechanical stability and optical accessibility. Modification of basal culture media with Leibovitz's L-15 medium enabled an incubator-free culture of carbonate-dependent cells by eliminating the need for exogenous carbon dioxide. This capability is demonstrated through time-lapse recording of proliferation of C2C12 myoblasts and MC3T3-E1 osteoblasts for over 2 weeks in ambient atmosphere without medium exchange. The method opens up new possibilities for portable cell culture and for long-term continuous visual monitoring of cells. PMID:16372083

Futai, Nobuyuki; Gu, Wei; Song, Jonathan W; Takayama, Shuichi

2006-01-01

128

Moist Recirculation and Water Vapor Transport on Dry Isentropes* FRE DE RIC LALIBERTE  

E-print Network

Moist Recirculation and Water Vapor Transport on Dry Isentropes* FRE´ DE´ RIC LALIBERTE´ Department in dry isentropic coordinates using reanalysis data is presented. The meridional mass fluxes on surfaces ascend on the equatorward side of storm tracks by following moist isentropes reminiscent of upright deep

Pauluis, Olivier M.

129

Embryonic development, hatching, mineral consumption, and survival of Macrobrachium rosenbergii (de Man) reared in artificial seawater in closed recirculating water system at different levels of salinity  

Microsoft Academic Search

This experiment aims to study the effect of different levels of salinity (5, 15 and 25 ppt) using artificial sea water on the embryonic development and hatching percentage of the eggs of unripe berried female giant freshwater prawns (Macrobrachium rosenbergii) with an average size of 14.3+0.6 cm TL. After incubation through the heart beating stage (grayish black eggs), the brooders

Krasindh Hangsapreurke; Thon Thamrongnawasawat; Sorawit Powtongsook; Prajuab Lumubol

130

EVALUATING THE IMPACT OF WATER CHEMISTRY ON CUPROSOLVENCY AND COPPER CORROSION BY-PRODUCT USING A SIMPLE COPPER PIPE RECIRCULATING LOOP SYSTEM  

EPA Science Inventory

1991, EPA publicized the Lead and Copper Rule (LCR),which set regulations to minimize the amount of lead copper in drinking water. The LCR set the copper action level at 1.3 mg/L in more then 10% of customer?s first-draw taps sampled. Potential health effects of copper include vo...

131

Power plant including an exhaust gas recirculation system for injecting recirculated exhaust gases in the fuel and compressed air of a gas turbine engine  

DOEpatents

A power plant is provided and includes a gas turbine engine having a combustor in which compressed gas and fuel are mixed and combusted, first and second supply lines respectively coupled to the combustor and respectively configured to supply the compressed gas and the fuel to the combustor and an exhaust gas recirculation (EGR) system to re-circulate exhaust gas produced by the gas turbine engine toward the combustor. The EGR system is coupled to the first and second supply lines and configured to combine first and second portions of the re-circulated exhaust gas with the compressed gas and the fuel at the first and second supply lines, respectively.

Anand, Ashok Kumar; Nagarjuna Reddy, Thirumala Reddy; Shaffer, Jason Brian; York, William David

2014-05-13

132

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

NASA Astrophysics Data System (ADS)

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.

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

2012-01-01

133

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

E-print Network

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

Watson, Craig A.

134

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...

135

Stressing fish in Recirculating Aquaculture Systems (RAS): Does stress induced in one group of fish affect the feeding motivation of other fish sharing the same RAS?  

Microsoft Academic Search

As a consequence of water re-use and high stocking densities, Recirculating Aquaculture Systems (RAS) may lead to an accumulation of substances released by the fish into the water, e.g. cortisol and alarm pheromones. This study investigated the effect of stressing fish on the feeding motivation of other fish not subjected to stress but sharing the same water of stressed fish.

C. I. Martins; E. H. Eding; J. A. J. Verreth

2011-01-01

136

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

E-print Network

COMPARISON OF HYDROPONIC CROP PRODUCTION TECHNIQUES IN A RECIRCULATING FISH CULTURE SYSTEM A Thesis by STEVEN WHITAKKR WREN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE December 1984 Major Subject: Wildlife and Fisheries Sciences COMPARISON OF HYDROPONIC CROP PRODUCTION TECHNIQUES IN A RECIRCULATING FISH CULTURE SYSTEM A Thesis by STEVEN WHITAKER WREN Approved as to style and content by...

Wren, Steven Whitaker

1984-01-01

137

Design and installation of a high Reynolds number recirculating water tunnel  

NASA Astrophysics Data System (ADS)

The High-Reynolds Number Fluid Mechanics Laboratory has recently been established at Oklahoma State University (OSU). The three primary components of the laboratory are 1) a recirculating water tunnel, 2) a multiphase pipe flow facility, and 3) a multi-scale flow visualization system. This thesis focuses on the design and fabrication of the water tunnel, which will be used for high-Reynolds number turbulent boundary layer research. Two main design criteria for the water tunnel were to achieve a momentum thickness based Reynolds number in excess of 104 and to have high optical access to the flow surfaces in the test section. This is being achieved with a 1 m. long test section and a maximum flow speed of 10 m/s. This Reynolds number was targeted to bridge the gap between typical university water tunnels (103) and the world's largest water tunnel facilities (105). The water tunnel is powered by a 150 hp motor and a 4500 gpm capacity centrifugal pump. The water tunnel is designed for a maximum operating pressure of 40 psi. This will make the facility a low cost option to perform high-Reynolds number aerodynamic and hydrodynamic tests. Improved flow imaging capability is a major advantage to liquid based fluid facilities because of the increased density for seeding and reduced field-of-view for equivalent Reynolds number. The laboratory's state-of-the-art flow visualization system can be used for time-resolved and phase averaged stereo- particle-image-velocimetry (sPIV), laser-induced-fluorescence, and high-speed imaging. Design provisions are also made to allow a multi-phase loop to share the pump and motor configuration of this water tunnel facility. The major design decisions that went into the design of the water tunnel facility are discussed. The design considerations that were taken into account for the test section, flow conditioning sections and the entire flow loop are discussed in greater detail. The final configuration and the technical drawings of the water tunnel flow loop, the test section, the contraction and diffuser sections are also provided. The installation procedure that will be utilized to install the water tunnel in the High Reynolds Number Fluid Mechanics Laboratory is also discussed.

Daniel, Libin

138

Temporal and spatial pore water pressure distribution surrounding a vertical landfill leachate recirculation well.  

PubMed

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

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

2011-05-01

139

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

PubMed Central

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

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

2011-01-01

140

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

NASA Astrophysics Data System (ADS)

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].

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

2002-04-01

141

Systems engineering for ornamental fish production in a recirculating aquaculture system  

Microsoft Academic Search

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

Ilan Halachmi

2006-01-01

142

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

Microsoft Academic Search

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

R. W. Bussard; K. E. King

1992-01-01

143

COMPARISON OF YIELD, NUTRIENT SOLUTION CHANGES AND NUTRITIONAL STATUS OF GREENHOUSE TOMATO GROWN IN RECIRCULATING AND NONRECIRCULATING NUTRIENT SOLUTION SYSTEMS  

Microsoft Academic Search

Studies were carried out in the years 2005–2007 with greenhouse tomato (Lycopersicon esculentum Mill.) cv. ‘Emotion F1’ grown in rockwool with the recirculating and non-recirculating nutrient solution systems. No significant differences were found in yields of fruits in both systems. In the recirculating system there was more intensive accumulation of sodium (Na), calcium (Ca), chloride (Cl), and zinc (Zn) in

A. Komosa; J. Piróg; Z. Weber; B. Markiewicz

2011-01-01

144

Chemical and sensory quantification of geosmin and 2-methylisoborneol in rainbow trout (Oncorhynchus mykiss) from recirculated aquacultures in relation to concentrations in basin water.  

PubMed

Globally, aquaculture systems with water recirculation experience increasing problems with microbial taste and odor compounds (TOCs) such as geosmin and 2-methylisoborneol (MIB). This study investigated the content of geosmin and MIB in water and the flesh of 200 rainbow trouts from eight recirculated aquaculture systems in Denmark. TOC content in the fish flesh was measured by a dynamic headspace extraction method and was evaluated by a sensory panel. The results showed significant correlations between TOC content in water and fish and between chemical analysis and sensory perception. When geosmin exceeded 20 ng/L in the water, 96% of the fish had an intense muddy flavor, but below 10 ng geosmin/L, 18% of the fish (only 3% in special depuration ponds) had an intense muddy flavor. The results indicate that TOC levels <10 ng/L will ensure that a negligible portion of the fish obtains an unpalatable taste and flavor due to TOCs. PMID:22040367

Petersen, Mikael A; Hyldig, Grethe; Strobel, Bjarne W; Henriksen, Niels H; Jørgensen, Niels O G

2011-12-14

145

A recirculating hydroponic system for studying peanut (Arachis hypogaea L.)  

NASA Technical Reports Server (NTRS)

Peanut (Arachis hypogaea L.) plants were grown hydroponically, using continuously recirculating nutrient solution. Two culture tray designs were tested; one tray design used only nutrient solution, while the other used a sphagnum-filled pod development compartment just beneath the cover and above the nutrient solution. Both trays were fitted with slotted covers to allow developing gynophores to reach the root zone. Peanut seed yields averaged 350 gm-2 dry mass, regardless of tray design, suggesting that substrate is not required for hydroponic peanut production.

Mackowiak, C. L.; Wheeler, R. M.; Stutte, G. W.; Yorio, N. C.; Ruffe, L. M.; Sager, J. C. (Principal Investigator)

1998-01-01

146

Internal dust recirculation system for a fluidized bed heat exchanger  

DOEpatents

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.

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

1981-01-01

147

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

SciTech Connect

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.

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

2012-05-01

148

Foam fractionation efficiency for particulate matter removal from a low salinity, lowhead recirculating aquaculture system utilized for the culture of red drum, Sciaenops ocellatus  

Technology Transfer Automated Retrieval System (TEKTRAN)

In recirculating aquaculture systems (RAS), the water which is treated and reused must be of such quality to maintain the culture organism in a healthy and fast growing condition, especially as such systems are intensified. Managing particulate matter and different chemical compounds is a key factor...

149

Prototype recirculating aquaculture system design for juvenile red drum production as part of the Florida Fish and Wildlife Conservation commission’s Hatchery Network Initative  

Technology Transfer Automated Retrieval System (TEKTRAN)

A prototype recirculating aquaculture system for the production of red drum (Sciaenops ocellatus) includes four 10-foot diameter by four foot height tanks for a tank volume of approximately 300 ft3 each (2200 gallons). Water flow for the system is provided for by a low head propeller pump which prov...

150

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

Microsoft Academic Search

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;

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

2005-01-01

151

Growth and survival of larval and juvenile cobia Rachycentron canadum in a recirculating raceway system  

Microsoft Academic Search

Cobia Rachycentron canadum is a fast-growing, pelagic marine species that has recently attracted aquaculturists in both the research and commercial sectors. The typical method of grow-out for this species is in outdoor systems where production is limited to locations and seasons conducive for adequate growth and survival. Expanding the culture of cobia to indoor recirculating aquaculture systems (RAS) would allow

Cynthia K. Faulk; Jeffrey B. Kaiser; G. Joan Holt

2007-01-01

152

PERFORMANCE OF A ROTATING BIOLOGICAL CONTRACTOR IN TILAPIA RECIRCULATING AQUACULTURE SYSTEM  

Technology Transfer Automated Retrieval System (TEKTRAN)

This paper describes the performance characteristics of an industrial-scale air-driven rotating biological contactor (RBC) installed in a recirculating aquaculture system (RAS) rearing tilapia at 28 oC. This 3-staged RBC system was configured with stages 1 and 2 possessing approximately the same to...

153

Effect of fish size and hydraulic regime on particulate organic matter dynamics in a recirculating aquaculture system: elemental carbon and nitrogen approach  

Microsoft Academic Search

Understanding the capabilities of particulate organic matter removal devices is critical to the development of recirculating aquaculture systems (RAS). The size of fish and water flow rates were evaluated as factors determining the distribution of particulate wastes throughout the RAS. Elemental carbon and nitrogen analyses (CHN) were employed in order to characterize particulate matter and to evaluate the performances of

M. A. Franco-Nava; J. P. Blancheton; G. Deviller; A. Charrier; J. Y. Le-Gall

2004-01-01

154

Evaluation of depuration procedures to mitigate off-flavor from harvest size Atlantic Salmon Salmo Salar cultured in a land-based recirculating aquaculture system  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fish cultured within water recirculating aquaculture systems (RAS) can develop “earthy” or “musty” off-flavors in their flesh due to the bioaccumulation of the compounds geosmin and 2-methylisoborenol (MIB), respectively, that are produced by certain bacteria (e.g., actinomycetes). These bacteria an...

155

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...

156

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

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.

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

1998-08-01

157

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 ...

158

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

Microsoft Academic Search

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

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

2009-01-01

159

Removal efficiency and balance of nitrogen in a recirculating aquaculture system integrated with constructed wetlands  

Microsoft Academic Search

The nitrogen (N) balance for aquaculture is an important aspect, especially in China, and it is attributed to the eutrophication in many freshwater bodies. In recent years, constructed wetlands (CWs) have been widely used in wastewater treatment and ecosystem restoration. A recirculating aquaculture system (RAS) consisting of CWs and 4 fish ponds was set up in Wuhan, China. Channel catfish

Fei Zhong; Wei Liang; Tao Yu; Shui P. Cheng; Feng He; Zhen B. Wu

2011-01-01

160

Part-day ozonation for nitrogen and organic carbon control in recirculating aquaculture systems  

Microsoft Academic Search

Recent work on ozone application in recirculating aquaculture systems (RAS) gives guidelines as to the daily ozone dose as a function of feed rates, but does not indicate whether the ozone should be added continuously throughout the day or in shorter, more intense doses. This study examined the effect of adding the same total amount of ozone (15 g ozone

Valdis Krumins; James Ebeling; Fred Wheaton

2001-01-01

161

Evaluation of nitrifying bacteria product to improve nitrification efficacy in recirculating aquaculture systems  

Microsoft Academic Search

Recirculating aquaculture systems (RASs) rely on nitrification to convert toxic ammonia and nitrite to less toxic nitrate. Nitrification is accomplished using biofilters with nitrifying bacteria and can be inefficient in biofilters that are new or that have been compromised due to stressors. Failure in a biofilter can result in very high levels of ammonia or nitrite, both of which are

David D. Kuhn; David D. Drahos; Lori Marsh; George J. Flick Jr.

2010-01-01

162

Low-head recirculating aquaculture system for juvenile red drum production  

Technology Transfer Automated Retrieval System (TEKTRAN)

The USDA Agricultural Research Service and the Center for Aquaculture and Stock Enhancement at Harbor Branch Oceanographic Institute-FAU (HBOI-FAU) are collaborating to evaluate low-head recirculating aquaculture system designs to intensively produce red drum juveniles as part of the Florida Fish an...

163

Experimental Bleaching of a Reef-Building Coral Using a Simplified Recirculating Laboratory Exposure System  

EPA Science Inventory

Determining stressor-response relationships in reef building corals is a critical need for researchers because of global declines in coral reef ecosystems. A simplified recirculating coral exposure system for laboratory testing of a diversity of species and morphologies of reef b...

164

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 ...

165

Quantitative role of shrimp fecal bacteria in organic matter fluxes in a recirculating shrimp aquaculture system.  

PubMed

Microorganisms play integral roles in the cycling of carbon (C) and nitrogen (N) in recirculating aquaculture systems (RAS) for fish and shellfish production. We quantified the pathways of shrimp fecal bacterial activities and their role in C- and N-flux partitioning relevant to culturing Pacific white shrimp, Penaeus (Litopenaeus) vannamei, in RAS. Freshly produced feces from P. vannamei contained 0.6-7 × 10(10) bacteria g(-1) dry wt belonging to Bacteroidetes (7%), Alphaproteobacteria (4%), and, within the Gammaproteobacteria, almost exclusively to the genus Vibrio (61%). Because of partial disintegration of the feces (up to 27% within 12 h), the experimental seawater became inoculated with fecal bacteria. Bacteria grew rapidly in the feces and in the seawater, and exhibited high levels of aminopeptidase, chitinase, chitobiase, alkaline phosphatase, ?- and ?-glucosidase, and lipase activities. Moreover, fecal bacteria enriched the protein content of the feces within 12 h, potentially enriching the feces for the coprophagous shrimp. The bacterial turnover time was much faster in feces (1-10 h) than in mature RAS water (350 h). Thus, shrimp fecal bacteria not only inoculate RAS water but also contribute to bacterial abundance and productivity, and regulate system processes important for shrimp health. PMID:21426366

Beardsley, Christine; Moss, Shaun; Malfatti, Francesca; Azam, Farooq

2011-07-01

166

[Performance of recirculating aquaculture systems in the intensive farming of Pacú Piaractus mesopotamicus (Characiformes: Characidae)].  

PubMed

An alternative to intensify fish production, reducing the environmental impact and production costs are recirculating aquaculture systems (RAS). The performance of a RAS was evaluated, as fish growth and water quality conditions, in a culture of Piaractus mesopotamicus reared for ornamental purposes. Two commercial food brands with different protein contents (18%-T1 and 28%-T2), were given to juvenile fishes during an eight weeks period. Growth was measured bi-weekly: standard length (Lp), peak height (A), weight and multiple condition factor (KM). The evaluation of water parameters included: dissolved oxygen, NH3-NH4, pH, NO2, NO3, KH carbonate hardness and PO4. NH3-N rate production was analyzed following Timmons-Ebeling model. Results demonstrated significant differences in weight only, and T2 showed a 7.5% higher value than T1; nevertheless, treatment T1 had a higher KM. In general, water quality values were suitable for growth: OD=T1: 4.23 +/- 1.23; T2: 4.13 +/- 0.86; NH3=T1: 0.02 +/- 0.02; T2: 0.06 +/- 0.10; however, pH was an exception (T1: 6.95 +/- 0.98; T2: 7.11 +/- 1.03), displaying lethal rates (<5) by the fifth week. Systems NH3 removal had a 99.4% to 100% efficiency. Final fish biomass was 22.03kg for T1 and 27.49kg for T2. We concluded that the systems were able to maintain suggested density up to the experimental fifth week. Water quality parameters remained in suitable levels, with the pH exception. Cultured fishes reached their commercial size (10cm) in eight weeks. PMID:22458232

Domínguez Castanedo, Omar; Martínez Espinosa, David Alberto

2012-03-01

167

The microbiology of a new recirculatory automatic watering system compared with a conventional automatic system  

Microsoft Academic Search

Summary Continual recirculation and filtration of drinking water prevents the contamination that often mars automatic watering systems by removing algae and fluorescent pseudomonads. Without filtration and recirculation, the algae were clearly visible after 40 days use, and the fluorescent pseudomonad count rose from 10' to 105 per ml after 72 h use. Automatic watering has many advantages compared with water

K. Taylor; G. Franklin; C. M. Shaw

1978-01-01

168

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

PubMed

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

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

2010-03-01

169

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

PubMed

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

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

2015-02-11

170

Florfenicol residues in rainbow trout after oral dosing in recirculating and flow-through culture systems.  

PubMed

Aquaflor is a feed premix for fish containing the broad spectrum antibacterial agent florfenicol (FFC) incorporated at a ratio of 50% (w/w). To enhance the effectiveness of FFC for salmonids infected with certain isolates of Flavobacterium psychrophilum causing cold water disease, the FFC dose must be increased from the standard 10 mg·kg?¹ body weight (BW)·d?¹ for 10 consecutive days. A residue depletion study was conducted to determine whether FFC residues remaining in the fillet tissue after treating fish at an increased dose would be safe for human consumption. Groups of Rainbow Trout Oncorhynchus mykiss (total n = 144; weight range, 126-617 g) were treated with FFC at 20 mg·kg?¹ BW·d?¹ for 10 d in a flow-through system (FTS) and a recirculating aquaculture system (RAS) each with a water temperature of ?13°C. The two-tank RAS included a nontreated tank containing 77 fish. Fish were taken from each tank (treated tank, n = 16; nontreated tank, n = 8) at 6, 12, 24, 48, 72, 120, 240, 360, and 480 h posttreatment. Florfenicol amine (FFA) concentrations (the FFC marker residue) in skin-on fillets from treated fish were greatest at 12 h posttreatment (11.58 ?g/g) in the RAS and were greatest at 6 h posttreatment (11.09 ?g/g) in the FTS. The half-lives for FFA in skin-on fillets from the RAS and FTS were 20.3 and 19.7 h, respectively. Assimilation of FFC residues in the fillets of nontreated fish sharing the RAS with FFC-treated fish was minimal. Florfenicol water concentrations peaked in the RAS-treated tank and nontreated tanks at 10 h (453 ?g/L) and 11 h (442 ?g/L) posttreatment, respectively. Monitoring of nitrite concentrations throughout the study indicated the nitrogen oxidation efficiency of the RAS biofilter was minimally impacted by the FFC treatment. PMID:25321636

Meinertz, J R; Hess, K R; Bernardy, J A; Gaikowski, M P; Whitsel, M; Endris, R G

2014-12-01

171

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

Microsoft Academic Search

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

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

2008-01-01

172

Performance and operation of a rotating biological contactor in a tilapia recirculating aquaculture system  

Microsoft Academic Search

This paper describes the performance characteristics of an industrial-scale air-driven rotating biological contactor (RBC) installed in a recirculating aquaculture system (RAS) rearing tilapia at 28°C. This three-staged RBC system was configured with stages 1 and 2 possessing approximately the same total surface area and stage 3 having approximately 25% smaller. The total surface area provided by the RBC equaled 13,380m2.

Brian L. Brazil

2006-01-01

173

The effect of temperature and pH on the growth and physiological response of juvenile yellowtail kingfish Seriola lalandi in recirculating aquaculture systems  

Microsoft Academic Search

A search for a viable new fish species for culture in recirculating aquaculture systems (RAS) in the Netherlands identified yellowtail kingfish Seriola lalandi as having excellent potential. To assist in determining the most appropriate water quality conditions for this species in RAS, the effect of water temperature (21, 23.5, 25, 26.5 and 29 °C) and pH (6.58, 7.16 and 7.85)

W. Abbink; A. Blanco; J. A. C. Roques; G. Partridge; K. Kloet; O. Schneider

2012-01-01

174

Membrane filtration coupled with chemical precipitation to treat recirculating aquaculture system effluents.  

PubMed

Effluents from recirculating aquaculture systems (RAS) contain high concentrations of nitrogen and phosphorous wastes and thus often require proper treatment to prevent potential detrimental impacts on receiving water bodies. The purpose of this study was to evaluate the feasibility of membrane filtration coupled with chemical precipitation as a pretreatment step with emphasis on phosphorus removal from RAS effluents. Chemical precipitation tests were conducted by adding magnesium chloride and alum at different chemical concentrations and pH values, respectively. Crossflow, flat-sheet membrane filtration modules were used to examine the effects of transmembrane pressure and crossflow velocity in terms of solid/liquid separation efficiency and permeate flux decline. The results showed that membrane filtration can effectively separate the phosphorus precipitates after chemical precipitation. The total phosphorus in the treated effluent was reduced to less than 0.05 mg L(-1) with a removal efficiency of more than 90%. However, much lower removal efficiencies were obtained for total organic carbon (TOC), total nitrogen, and turbidity. It was concluded that membrane filtration coupled with chemical precipitation can become an effective, compact treatment technology to meet the stringent regulatory requirements for RAS effluent discharge. PMID:17071913

Yang, Ling; Zhou, Hongde; Moccia, Richard

2006-01-01

175

Milli-Q Reference Water Purification System  

E-print Network

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

Woodall, Jerry M.

176

Downhole weir for measuring flow rate in recirculation wells  

Microsoft Academic Search

Recirculating wells are increasingly being used for ground water remediation and aquifer characterization investigations. Determination of flow rate is required for proper design and spacing of recirculation wells. The measurement of flow rate, however, can be difficult using standard equipment. To overcome some of the flow measurement problems associated with more common measurement systems, a new device in the form

Tyler Gilmore; John Davis; James Coates

1998-01-01

177

A bioeconomic evaluation of a commercial scale recirculating finfish growout system — An Australian perspective  

Microsoft Academic Search

This study, based on 3 years of commercial data, presents the results of an economic analysis of a 20-tonne per annum (TPA) commercial recirculating aquaculture system (RAS) facility located in Warrnambool, Victoria, Australia. Based on the assumptions of the analysis, results highlight the non-viability of the facility, with a 10-year projected negative cumulative cash flow of ?$648,038, and negative net present

Paul N. De Ionno; Graeme L. Wines; Paul L. Jones; Robert O. Collins

2006-01-01

178

Growth of juvenile Atlantic cod Gadus morhua in land-based recirculation systems  

Microsoft Academic Search

The combined effect of feeding regime and photoperiod on the growth of juvenile Atlantic cod Gadus morhua in land-based recirculating aquaculture systems (RAS) was examined using three different commercial diets. Fish of 8–10 g were reared in 1 m3 tanks at an initial density of 10 kg m?3 for 78 d. Three RAS units were used to simultaneously test three feed\\/photoperiod regimes that might

M. Fülberth; D. Moran; H. Jarlbæk; J. G. Støttrup

2009-01-01

179

Noncardiogenic pulmonary edema induced by a molecular adsorbent recirculating system: case report  

Microsoft Academic Search

Noncardiogenic pulmonary edema is a well-recognized manifestation of acute lung injury which has been related, among others, to blood or blood-product transfusion, intravenous contrast injection, air embolism, and drug ingestion. We describe two cases of noncardiogenic pulmonary edema after use of a molecular adsorbent recirculating system, a cell-free dialysis technique. Patients in this series presented at our institution to be

Cataldo Doria; Lucio MandalÀ; Victor L. Scott; Ignazio R. Marino; Salvatore Gruttadauria; Roberto Miraglia; Claudio H. Vitale; Jan Smith

2003-01-01

180

Florfenicol residues in Rainbow Trout after oral dosing in recirculating and flow-through culture systems  

USGS Publications Warehouse

Aquaflor is a feed premix for fish containing the broad spectrum antibacterial agent florfenicol (FFC) incorporated at a ratio of 50% (w/w). To enhance the effectiveness of FFC for salmonids infected with certain isolates of Flavobacterium psychrophilum causing coldwater disease, the FFC dose must be increased from the standard 10 mg·kg?1 body weight (BW)·d?1 for 10 consecutive days. A residue depletion study was conducted to determine whether FFC residues remaining in the fillet tissue after treating fish at an increased dose would be safe for human consumption. Groups of Rainbow Trout Oncorhynchus mykiss (total n = 144; weight range, 126–617 g) were treated with FFC at 20 mg·kg?1 BW·d?1 for 10 d in a flow-through system (FTS) and a recirculating aquaculture system (RAS) each with a water temperature of ?13°C. The two-tank RAS included a nontreated tank containing 77 fish. Fish were taken from each tank (treated tank, n = 16; nontreated tank, n = 8) at 6, 12, 24, 48, 72, 120, 240, 360, and 480 h posttreatment. Florfenicol amine (FFA) concentrations (the FFC marker residue) in skin-on fillets from treated fish were greatest at 12 h posttreatment (11.58 ?g/g) in the RAS and were greatest at 6 h posttreatment (11.09 ?g/g) in the FTS. The half-lives for FFA in skin-on fillets from the RAS and FTS were 20.3 and 19.7 h, respectively. Assimilation of FFC residues in the fillets of nontreated fish sharing the RAS with FFC-treated fish was minimal. Florfenicol water concentrations peaked in the RAS-treated tank and nontreated tanks at 10 h (453 ?g/L) and 11 h (442 ?g/L) posttreatment, respectively. Monitoring of nitrite concentrations throughout the study indicated the nitrogen oxidation efficiency of the RAS biofilter was minimally impacted by the FFC treatment.

Meinertz, Jeffery R.; Hess, Karina R.; Bernady, Jeffry A.; Gaikowski, M. P.; Whitsel, Melissa; Endris, R. G.

2014-01-01

181

Integrated exhaust gas recirculation and charge cooling system  

SciTech Connect

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.

Wu, Ko-Jen

2013-12-10

182

Investigations into the reproductive performance and larval rearing of the Brown shrimp, Farfantepenaeus aztecus, using closed recirculating systems  

E-print Network

The effects of unilateral eyestalk ablation, diets and sex ratios were evaluated on two wild populations of Farfantepenaeus aztecus in a closed recirculating maturation system. Ovarian development and spawning frequencies of ablated females in both...

Gandy, Ryan Leighton

2005-02-17

183

Prediction of central recirculation zone size for a complete burner-quarl-furnace system  

NASA Astrophysics Data System (ADS)

In the swirl flow burning process of fuels, the central recirculation zone plays an important role in flame stabilization by providing a hot flow of recirculated combustion products, which reduce both the length of flame and the stabilized flame distance from the burner mouth. In this paper, a new modified swirl number, S exp xx, related to the characteristic size of the burner quarl, is introduced to correlate the isothermal and burning flows. Using a well-known two-dimensional computational model, the isothermal flow pattern in a complete burner-quarl-furnace system is computed. On this basis, the theoretical swirl number S exp xx is calculated and used as a correlation parameter for predicting the central recirculation zone size in burning flow conditions. Experimental tests for both nonreacting and reacting flows on the same complete burner-quarl-furnace system, for comparing the theoretical and experimental swirl number s exp xx, have been conducted, and the validity of this new correlation parameter has been proved.

Cristea, Eugen-Dan B.

1987-03-01

184

Removal efficiency and balance of nitrogen in a recirculating aquaculture system integrated with constructed wetlands.  

PubMed

The nitrogen (N) balance for aquaculture is an important aspect, especially in China, and it is attributed to the eutrophication in many freshwater bodies. In recent years, constructed wetlands (CWs) have been widely used in wastewater treatment and ecosystem restoration. A recirculating aquaculture system (RAS) consisting of CWs and 4 fish ponds was set up in Wuhan, China. Channel catfish (Ictalurus punctatus) fingerlings were fed for satiation daily for 168 days with 2 diets containing 5.49 % and 6.53 % nitrogen, respectively. The objectives of this study were to investigate the N budget in the RAS, and try to find out the feasibility of controlling N accumulation in the fish pond. It is expected that the study can provide a mass balance for the fate of N in the eco-friendly treatment system to avoid eutrophication. The results showed that the removal rates of ammonia (NH(+)(4)-N), sum of nitrate & nitrite (NO(-)(X)-N), and total nitrogen (TN) by the CWs were 20-55%, 38-84 % and 39-57 %, respectively. Denitrification in the CWs was the main pathway of nitrogen loss (41.67 %). Nitrogen accumulation in pond water and sediment accounted for 3.39 % and 12.65 % of total nitrogen loss, respectively. The nitrogen removal efficiency and budget showed that the CW could be used to control excessive nitrogen accumulation in fish ponds. From the viewpoint of the nitrogen pollution control, the RAS combined with the constructed wetland can be applied to ensure the sustainable development for aquaculture. PMID:21644158

Zhong, Fei; Liang, Wei; Yu, Tao; Cheng, Shui P; He, Feng; Wu, Zhen B

2011-01-01

185

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

PubMed

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

Pungrasmi, Wiboonluk; Playchoom, Cholticha; Powtongsook, Sorawit

2013-08-01

186

Production Characteristics and Body Composition of Florida Pompano Reared to Market Size at Two Different Densities in Low-Salinity Recirculating Aquaculture Systems  

Microsoft Academic Search

The effect of culture density on production characteristics and body composition of Florida pompano Trachinotus carolinus reared to market size using recirculating aquaculture systems (RASs) maintained at a salinity of 5‰ was evaluated in a 110-d growth trial (water temperature = 27.0–28.5°C). Juvenile Florida pompano (mean weight ± SE = 259.0 ± 3.0 g) were stocked into two tanks from

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

2009-01-01

187

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

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,

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

2008-01-01

188

Argon purification studies and a novel liquid argon re-circulation system  

NASA Astrophysics Data System (ADS)

Future giant liquid argon (LAr) time projection chambers (TPCs) require a purity of better than 0.1 parts per billion (ppb) to allow the ionised electrons to drift without significant capture by any electronegative impurities. We present a comprehensive study of the effects of electronegative impurity on gaseous and liquid argon scintillation light, an analysis of the efficiency of various purification chemicals, as well as the Liverpool LAr setup, which utilises a novel re-circulation purification system. Of the impurities tested - Air, O2, H2O, N2 and CO2 in the range of between 0.01 ppm to 1000 ppm - H2O was found to have the most profound effect on gaseous argon scintillation light, and N2 was found to have the least. Additionally, a correlation between the slow component decay time and the total energy deposited with 0.01 ppm - 100 ppm O2 contamination levels in liquid argon has been established. The superiority of molecular sieves over anhydrous complexes at absorbing Ar gas, N2 gas and H2O vapour has been quantified using BET isotherm analysis. The efficiency of Cu and P2O5 at removing O2 and H2O impurities from 1 bar N6 argon gas at both room temperature and -130 °C was investigated and found to be high. A novel, highly scalable LAr re-circulation system has been developed. The complete system, consisting of a motorised bellows pump operating in liquid and a purification cartridge, were designed and built in-house. The system was operated successfully over many days and achieved a re-circulation rate of 27 litres/hour and high purity.

Mavrokoridis, K.; Calland, R. G.; Coleman, J.; Lightfoot, P. K.; McCauley, N.; McCormick, K. J.; Touramanis, C.

2011-08-01

189

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

SciTech Connect

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.

Burden, D.G.

1988-01-01

190

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

NASA Technical Reports Server (NTRS)

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.

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

1975-01-01

191

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

SciTech Connect

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

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

1992-01-01

192

Single-pipe hot water solar system  

Microsoft Academic Search

A hot water solar system receives water from a source and heats it in solar panels. From the solar panels it is circulated through a supplemental heater and through a domestic heating system and thus made available for domestic use in washers and baths and is then recirculated through the solar panels. In the event the solar panels will not

Geaslin

1980-01-01

193

Photocatalytic reactors for treating water pollution with solar illumination. III: a simplified analysis for recirculating reactors  

Microsoft Academic Search

A solar photoreactor operated in the batch, recirculating mode is analyzed in terms of very simple observable variables such as the impinging photon flux, the incident area, the initial concentration, the flow rate, the reactor volume and a property defined as the Observed Photonic Efficiency. The proposed equipment is made of a tubular reactor, a tank, a pump and the

Gerd Sagawe; Rodolfo J. Brandi; Detlef Bahnemann; Alberto E. Cassano

2004-01-01

194

Effect of stocking density on performances of juvenile turbot ( Scophthalmus maximus) in recirculating aquaculture systems  

NASA Astrophysics Data System (ADS)

Limited information has been available about the influence of loading density on the performances of Scophthalmus maximus, especially in recirculating aquaculture systems (RAS). In this study, turbot (13.84±2.74 g; average weight±SD) were reared at four different initial densities (low 0.66, medium 1.26, sub-high 2.56, high 4.00 kg/m2) for 10 weeks in RAS at 23±1°C. Final densities were 4.67, 7.25, 14.16, and 17.47 kg/m2, respectively, which translate to 82, 108, 214, and 282 percent coverage of the tank bottom. Density had both negative and independent impacts on growth. The final mean weight, specific growth rate (SGR), and voluntary feed intake significantly decreased and the coefficient of variation (CV) of final body weight increased with increase in stocking density. The medium and sub-high density groups did not differ significantly in SGR, mean weight, CV, food conversion rate (FCR), feed intake, blood parameters, and digestive enzymes. The protease activities of the digestive tract at pH 7, 8.5, 9, and 10 were significantly higher for the highest density group, but tended to be lower (not significantly) at pH 4 and 8.5 for the lowest density group. The intensity of protease activity was inversely related to feed intake at the different densities. Catalase activity was higher (but not significantly) at the highest density, perhaps because high density started to induce an oxidative effect in turbot. In conclusion, turbot can be cultured in RAS at a density of less than 17.47 kg/m2. With good water quality and no feed limitation, initial density between 1.26 and 2.56 kg/m2 (final: 7.25 and 14.16 kg/m2) would not negatively affect the turbot cultured in RAS. For culture at higher density, multi-level feeding devices are suggested to ease feeding competition.

Li, Xian; Liu, Ying; Blancheton, Jean-Paul

2013-05-01

195

AP1000 Features Prevent Potential Containment Recirculation Screen Plugging  

SciTech Connect

This paper presents the results of plant design development and evaluations that demonstrate that the AP1000 plant is not subject to potential containment recirculation screen plugging following a loss-of-coolant-accident (LOCA). Following a LOCA in a pressurized water reactor, it is necessary to recirculate water from the containment back into the reactor to maintain long term core cooling. The AP1000 utilizes passive safety systems to provide containment recirculation for long term core cooling following a LOCA. The AP1000 also has non-safety pumps which provide a backup means of providing recirculation. Screens are provided around the recirculation pipes to prevent debris from blocking recirculation flow and core cooling passages. Debris may be generated by the LOCA blowdown from insulation and coatings used inside containment. Even with effective cleanliness programs, there may be some resident debris such as dust and dirt. The potential for plugging the recirculation screens is a current PWR licensing issue. The AP1000 design provides inherent advantages with respect to the potential plugging of containment recirculation screens. These characteristics include prevention of fibrous debris generation, improved debris settling and improved recirculation screen design. Debris settling analysis demonstrates that failure of coatings does not result in debris being transported to the screens before it settles to the floor. Additional analysis also shows that the plant can tolerate conservative amounts of resident debris being transported to the screens. The AP1000 significantly reduces the probability of plugging the containment recirculation screens and significantly reduces inspection and maintenance of coatings used inside containment. (authors)

Andreychek, Timothy; Anderson, Richard; Schulz, Terry [Westinghouse Electric Company, LLC, P.O. Box 355, Pittsburgh, PA, 15230 (United States)

2004-07-01

196

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. ...

197

Particulate matter dynamics and transformations in a recirculating aquaculture system: application of stable isotope tracers in seabass rearing  

Microsoft Academic Search

The control of adverse effects and the possibility of removing suspended solids from recirculating aquaculture systems (RAS) are the principal challenges facing aquaculture engineers. However, their dynamics and transformations are not yet well known. In this study, carbon and nitrogen stable isotopes values (?13C and ?15N) were used as tracers of particulate matter in a seabass RAS. An isotopic mixing

Miguel-Angel Franco-Nava; Jean-Paul Blancheton; Geneviève Deviller; Jean-Yves Le-Gall

2004-01-01

198

Establishment of a real-time PCR method for quantification of geosmin-producing Streptomyces spp. in recirculating aquaculture systems  

Microsoft Academic Search

Geosmin and 2-methylisoborneol (MIB) have been associated with off-flavour problems in fish and seafood products, generating a strong negative impact for aquaculture industries. Although most of the producers of geosmin and MIB have been identified as Streptomyces species or cyanobacteria, Streptomyces spp. are thought to be responsible for the synthesis of these compounds in indoor recirculating aquaculture systems (RAS). The

Marc Auffret; Alexandre Pilote; Émilie Proulx; Daniel Proulx; Grant Vandenberg; Richard Villemur

199

Evaluation of a low-head recirculating aquaculture system used for rearing Florida pompano to market size  

Technology Transfer Automated Retrieval System (TEKTRAN)

A low-head recirculating aquaculture system (RAS) was evaluated for the production Florida pompano Trachinotus carolinus from juvenile to market size. The RAS consisted of three dual-drain, 3-m diameter culture tanks of 7.8 m3 volume each, two 0.7-m3 moving bed bioreactors filled 67% with K1 kaldnes...

200

Preliminary studies on the depuration of common off-flavors from fish raised in recirculating aquaculture systems  

Technology Transfer Automated Retrieval System (TEKTRAN)

“Off-flavor” problems can adversely impact the growth of the aquaculture industry. Fish raised in recirculating systems have the potential to develop the common off-flavors “earthy” and “musty” due to accumulation of the microbial metabolites geosmin and 2-methylisoborneol (MIB) in the fish flesh. ...

201

High ratio recirculating gas compressor  

DOEpatents

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.

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

1989-01-01

202

High ratio recirculating gas compressor  

DOEpatents

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.

Weinbrecht, J.F.

1989-08-22

203

Method for preventing oxygen corrosion in a boiling water nuclear reactor and improved boiling water reactor system  

SciTech Connect

This patent describes a method for prevention of corrosion, due to oxygen activity, in a boiling water nuclear reactor system having a main feedwater recirculation loop comprising a reactor vessel with a reactor core and with a steam off-take line and a condensate return line in flow communication with the vessel for recirculating feedwater between the reactor and a steam turbine. The coolant water recirculation loops consist of coolant water off-take and return lines in flow communication with the vessel for recirculating coolant water in the vessel, wherein hydrogen is added to the coolant water passing through the reactor core to reduce the oxygen content of the coolant water. The improvement consists of: recirculation coolant water containing dissolved oxygen, after passage through the reactor core, is diverted from the recirculation loop; hydrogen gas is added to the diverted coolant water; the hydrogen-containing diverted coolant water is contacted with a catalyst effective to enhance reaction of hydrogen with oxygen contained in the coolant water; and the diverted coolant water, after reaction of the hydrogen gas with the oxygen contained therein, is returned to the recirculation loop for passage through the reactor core.

Desilva, S.G.

1989-06-27

204

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

USGS Publications Warehouse

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.

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

2013-01-01

205

Optimization of two-phase thermophilic anaerobic digestion of biowaste for hydrogen and methane production through reject water recirculation.  

PubMed

The optimization of a two-phase thermophilic anaerobic process treating biowaste for hydrogen and methane production was carried out at pilot scale using two stirred reactors (CSTRs) and without any physical/chemical pre-treatment of inoculum. During the experiment the hydrogen production at low hydraulic retention time (3d) was tested, both with and without reject water recirculation and at two organic loading rate (16 and 21 kgTVS/m3 d). The better yields were obtained with recirculation where the pH reached an optimal value (5.5) thanks to the buffering capacity of the recycle stream. The specific gas production of the first reactor was 51 l/kgVS(fed) and H2 content in biogas 37%. The mixture of gas obtained from the two reactors met the standards for the biohythane mix only when lower loading rate were applied to the first reactor, with a composition of 6.7% H2, 40.1% CO2 and 52.3% CH4 the overall SGP being 0.78 m3/kgVS(fed). PMID:21511465

Cavinato, C; Bolzonella, D; Fatone, F; Cecchi, F; Pavan, P

2011-09-01

206

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

PubMed

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

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

2014-10-01

207

Exhaust gas recirculation system having flow control valve combined with supersonic nozzle  

SciTech Connect

A channel is disclosed for recirculating a portion of an engine exhaust gas to the induction passage has an intermediately arranged converging-diverging supersonic nozzle with a valve member arranged in the nozzle to vary the cross-sectional area of the channel at the throat, so that the mass flow rate of the recirculated exhaust gas depends solely on the cross-sectional area so far as the gas velocity at the throat is sonic.

Sugihara, K.; Yamamoto, T.; Yoneda, K.

1981-08-25

208

Ammonia-oxidizing archaea and nitrite-oxidizing nitrospiras in the biofilter of a shrimp recirculating aquaculture system.  

PubMed

This study analysed the nitrifier community in the biofilter of a zero discharge, recirculating aquaculture system (RAS) for the production of marine shrimp in a low density (low ammonium production) system. The ammonia-oxidizing populations were examined by targeting 16S rRNA and amoA genes of ammonia-oxidizing bacteria (AOB) and archaea (AOA). The nitrite-oxidizing bacteria (NOB) were investigated by targeting the 16S rRNA gene. Archaeal amoA genes were more abundant in all compartments of the RAS than bacterial amoA genes. Analysis of bacterial and archaeal amoA gene sequences revealed that most ammonia oxidizers were related to Nitrosomonas marina and Nitrosopumilus maritimus. The NOB detected were related to Nitrospira marina and Nitrospira moscoviensis, and Nitrospira marina-type NOB were more abundant than N. moscoviensis-type NOB. Water quality and biofilm attachment media played a role in the competitiveness of AOA over AOB and Nitrospira marina-over N. moscoviensis-type NOB. PMID:22775980

Brown, Monisha N; Briones, Aurelio; Diana, James; Raskin, Lutgarde

2013-01-01

209

[Nitrate removal from recirculating aquaculture system using polyhydroxybutyrate-co-hydroxyvalerate as carbon source ].  

PubMed

[ OBJECTIVE] Polyhydroxybutyrate-co-hydroxyvalerate (PHBV) was used as solid carbon source and biofilm carrier to remove nitrate from recirculating aquaculture system (RAS). Dynamics of microbial community structure in biofilm coating on carbon source packed into denitrification reactor were investigated. [METHODS] Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) was used to analyze the microbial community in biofilm from denitrifiation reactor. Bacteria degrading PHBV were isolated from the reactor using pure culture method. [RESULTS] Nitrate decreased remarkably in the RAS connected with dentrification reactor. In contrast, Nitrate increased continuously in the conventional RAS without dentrification reactor. According to the phylogenetic analysis, the microbes in the biofilm samples from denitrification reactor were divided into Proteobacteria ( p-proteobacteria, ?-proteobacteria and ?- proteobacteria) , Firmicutes and Bacteroidetes. The major advantageous populations were Acidovorax and Bacillus in the 40-day reactor. The advantageous populations in the 150-day reactor were in order of Clostridium, Desulfitobacterium, Dechloromonas, Pseudoxanthomonas and Flavobacterium. Pure cultures of bacteria degrading PHBV isolated from denitrification reactor were classified into Acidovorax, Methylibium, Pseudoxanthomonas and Dechloromonas. [CONCLUSION] Nitrate could be removed effectively from RAS using PHBV as carbon source. Advantageous bacteria and their dynamic changes were ascertained in biofilm from denitrification reactor packed with PHBV. PMID:25522594

Zhang, Lanhe; Liu, Lili; Qiu, Tianlei; Gao, Min; Han, Meilin; Yuan, Ding; Wang, Xuming

2014-09-01

210

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

SciTech Connect

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.

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

2012-09-30

211

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

PubMed

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

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

2011-01-01

212

Evaluation of a recirculating pond system for rearing juvenile freshwater mussels at White Sulphur Springs National Fish Hatchery, West Virginia, U.S.A.  

USGS Publications Warehouse

A recirculating double-pond system at White Sulphur Springs National Fish Hatchery in West Virginia, U.S.A., was evaluated for suitability for culturing juvenile freshwater mussels. Newly metamorphosed juveniles of Villosa iris and Lampsilis fasciola were placed in the system, and their growth and survival were evaluated for 94 days. Throughout the study, parameters of water quality remained within ranges suitable for mussel survival. Planktonic algal densities in the pond system ranged from 2850 to 6892 cells/ml. Thirty-seven algal taxa were identified, primarily green algae (Chlorophyta), diatoms (Bacillariophyceae), and blue-green algae (Cyanoprokaryota). Over the culture period, juveniles of L. fasciola experienced significantly lower (p < 0.001) survival (6.3% ?? 4.5) than those of V. iris (49.8% ?? 14.5). The very low survival rate of L. fasciola may indicate a failure of the flow-through pond environment to meet its habitat requirements or that variable microhabitat conditions within culture containers existed. Growth did not differ significantly between the species (p = 0.13). Survival of V. iris and growth of both species were similar to previous trials to culture juvenile mussels. Survival rates as high as 66.4% at 93 days for V. iris suggest that juveniles of some riverine species can be successfully cultured in a recirculating pond environment.

Mummert, A.; Newcomb, T.J.; Neves, R.J.; Parker, B.

2006-01-01

213

Are perfluoroalkyl acids in waste water treatment plant effluents the result of primary emissions from the technosphere or of environmental recirculation?  

PubMed

Wastewater treatment plants (WWTP) have been suggested to be one of the major pathways of perfluoroalkyl acids (PFAAs) from the technosphere to the aquatic environment. The origin of PFAAs in WWTP influents is either from current primary emissions or a result of recirculation of PFAAs that have been residing and transported in the environment for several years or decades. Environmental recirculation can then occur when PFAAs from the environment enter the wastewater stream in, e.g., tap water. In this study 13 PFAAs and perfluorooctane sulfonamide were analyzed in tap water as well as WWTP influent, effluent and sludge from three Swedish cities: Bromma (in the metropolitan area of Stockholm), Bollebygd and Umeå. A mass balance of the WWTPs was assembled for each PFAA. Positive mass balances were observed for PFHxA and PFOA in all WWTPs, indicating the presence of precursor compounds in the technosphere. With regard to environmental recirculation, tap water was an important source of PFAAs to the Bromma WWTP influent, contributing >40% for each quantified sulfonic acid and up to 30% for the carboxylic acids. The PFAAs in tap water from Bollebygd and Umeå did not contribute significantly to the PFAA load in the WWTP influents. Our results show that in order to estimate current primary emissions from the technosphere, it may be necessary to correct the PFAA emission rates in WWTP effluents for PFAAs present in tap water, especially in the case of elevated levels in tap water. PMID:25139477

Filipovic, Marko; Berger, Urs

2015-06-01

214

Water Quality Monitoring in a Pilot Marine Integrated Aquaculture System  

Microsoft Academic Search

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

Alex W. Kruglick

2012-01-01

215

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

E-print Network

aquaculture Amit Grossa , Anna Nemirovskya , Dina Zilbergb , Anna Khaimova , Asher Brennerc , Eviatar Snird aquaculture relies on biofilters to sustain satisfactory water quality in the ponds. Establishment of new biofilters in aquaculture ponds without a start-up culture requires a long period of time and may therefore

Gross, Amit

216

Comparative performance of CO2 measuring methods: Marine aquaculture recirculation system application  

Technology Transfer Automated Retrieval System (TEKTRAN)

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 CO2in aquaculture systems. However, titrimetric determination of dissolved CO2 in marine water aquaculture systems is unsuitabl...

217

Modelling thermal environment of a recirculating aquaculture facility  

Microsoft Academic Search

Economic viability of fish production in a recirculating aquaculture system (RAS) facility depends, in part, on minimizing the energy requirements of operating such facilities. A step-wise, steady-state thermal model was developed to simulate the RAS thermal environment and energy expenditure for heating, ventilation, water pumping, biofilter operation, and lighting over a production cycle. The model was validated using temperature and

Sahdev Singh; Lori S. Marsh

1996-01-01

218

Review article Disinfestation of recirculating nutrient solutions  

E-print Network

) Abstract ­ Recirculating nutrient systems offer a good method to control nutrient leaching from greenhouses of recirculating nutrient systems by the greenhouse industry. This review discusses and compares five broadly different methods of disease control in these systems, namely heat, filtration, chemical, radiation

Boyer, Edmond

219

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...

220

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...

221

Nitrogen stable isotopes in recirculating aquaculture for super-intensive shrimp production: Tracing the effects of water filtration on microbial nitrogen cycling  

Microsoft Academic Search

To understand how filtration affected microbial community nitrogen (N) cycling, natural abundance stable isotope ratios of suspended particles and nitrate (NO3?) were measured in recirculating aquaculture systems (RAS) for the super-intensive culture (425shrimpm?2) of Pacific white shrimp, Litopenaeus vannamei. Samples were collected throughout a trial during which triplicate RAS were equipped with either a foam fractionator (FF) or a propeller-washed

Carolyn M. Holl; Christine Tallamy Glazer; Shaun M. Moss

2011-01-01

222

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

PubMed

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

Brazeau, Randi H; Edwards, Marc A

2013-10-01

223

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

PubMed Central

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

Brazeau, Randi H.; Edwards, Marc A.

2013-01-01

224

Effect of pressure and pH in ammonium retention for nanofiltration and reverse osmosis membranes to be used in recirculation aquaculture systems (RAS)  

Microsoft Academic Search

Recirculation systems are becoming widely used in the aquaculture industry, where ammonium removal results are crucial for a proper performance considering its high toxicity on fish. The objective of this study was to assess the ammonium retention, when the transmembrane pressure (TMP) in nanofiltration (NF) and reverse osmosis (RO) membranes are changed. Two pH levels were tested: pH 5, where

Beatriz Cancino-Madariaga; Carlos Felipe Hurtado; Rene Ruby

225

Influence of feeding level on growth, intraspecific weight variability and sexual growth dimorphism of Eurasian perch Perca fluviatilis L. reared in a recirculation system  

Microsoft Academic Search

The influence of the feeding level (FL) on growth and sexual growth dimorphism, was investigated in juvenile Eurasian perch (10 g initial body weight) reared in a recirculation system over 84 days. Fish were divided into groups of 105 individuals and fed three feeding levels: 1, 2 and 3% of the fish biomass (3 replicates\\/FL). Survival was not significantly (P

Pascal Fontaine; Jean Noel Gardeur; Patrick Kestemont; André Georges

1997-01-01

226

Efficient random subcloning of DNA sheared in a recirculating point-sink flow system.  

PubMed Central

Based on a high-performance liquid chromatographic pump, we have built a device that allows recirculation of DNA through a 63-microm orifice with ensuing fractionation to a minimum fragment size of approximately 300 base pairs. Residence time of the DNA fragments in the converging flow created by a sudden contraction was found to be sufficiently long to allow extension of the DNA molecules into a highly extended conformation and, hence, breakage to occur at midpoint. In most instances, 30 passages sufficed to obtain a narrow size distribution, with >90% of the fragments lying within a 2-fold size distribution. The shear rate required to achieve breakage was found to be inversely proportional to the 1.0 power of the molecular weight. Compared with a restriction digest, up to 40% of all fragments could be cloned directly, with only marginal improvements in cloning efficiency having been observed upon prior end repair with Klenow, T4 polymerase or T4 polynucleotide kinase. Sequencing revealed a fairly random distribution of the fragments. PMID:8918787

Oefner, P J; Hunicke-Smith, S P; Chiang, L; Dietrich, F; Mulligan, J; Davis, R W

1996-01-01

227

Molecular analysis of bacterial communities and detection of potential pathogens in a recirculating aquaculture system for Scophthalmus maximus and Solea senegalensis.  

PubMed

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

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

2013-01-01

228

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

PubMed Central

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

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

2013-01-01

229

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)

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.

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

2015-03-01

230

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

USGS Publications Warehouse

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.

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

2011-01-01

231

Exhaust gas recirculating apparatus  

Microsoft Academic Search

The design is given of apparatus associated with an engine on a motor vehicle for either stopping the recirculation of exhaust gas through the engine completely or allowing it at a controlled rate, depending upon the operating condition of the engine. A regulating valve provided with a pair of diaphragms is installed in the exhaust gas recirculating circuit, and a

H. Nohira; K. Kobashi

1975-01-01

232

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.

233

Peracetic acid degradation and effects on nitrification in recirculating aquaculture systems  

Microsoft Academic Search

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

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

2009-01-01

234

Recirculation System for Geothermal Energy Recovery in Sedimentary Formations: Laboratory Experiments and Numerical Simulations  

NASA Astrophysics Data System (ADS)

Geothermal energy resources are more widespread than previously thought and have the potential for providing a significant amount of sustainable clean energy worldwide. In particular, hot permeable sedimentary formations provide many advantages over traditional geothermal recovery and enhanced geothermal systems in low permeability crystalline formations. These include: (1) eliminating the need for hydraulic fracturing, (2) significant reduction in risk for induced seismicity, (3) reducing the need for surface wastewater disposal, (4) contributing to decreases in greenhouse gases, and (5) potential use for CO2 sequestration. Advances in horizontal drilling, completion, and production technology from the oil and gas industry can now be applied to unlock these geothermal resources. Here, we present experimental results from a laboratory scale circulation system and numerical simulations aimed at quantifying the heat transfer capacity of sedimentary rocks. Our experiments consist of fluid flow through a saturated and pressurized sedimentary disc of 23-cm diameter and 3.8-cm thickness heated along its circumference at a constant temperature. Injection and production ports are 7.6-cm apart in the center of the disc. We used DI de-aired water and mineral oil as working fluids and explored temperatures from 20 to 150 oC and flow rates from 2 to 30 ml/min. We performed experiments on sandstone samples (Castlegate and Kirby) with different porosity, permeability and thermal conductivity to evaluate the effect of hydraulic and thermal properties on the heat transfer capacity of sediments. The producing fluid temperature followed an exponential form with time scale transients between 15 and 45 min. Steady state outflow temperatures varied between 60% and 95% of the set boundary temperature, higher percentages were observed for lower temperatures and flow rates. We used the flow and heat transport simulator TOUGH2 to develop a numerical model of our laboratory setting. Given the remarkable match between our observations and numerical results, we extended our model to explore a wider range of thermal and hydrological parameters beyond the experimental conditions. Our results prove the capability of heat transfer in sedimentary formations for geothermal energy production.) Sandstone sample with two thermally insulating Teflon caps (white discs). In and out arrows indicate the flow direction while the sample is heated along its circumference (heater not shown). B) Example of a 2D temperature distribution during injection. White x shows the location of the flow ports, inlet (left) and outlet (right). Red is the set boundary temperature and blue is the fluid temperature at the inlet.

Elkhoury, J. E.; Detwiler, R. L.; Serajian, V.; Bruno, M. S.

2012-12-01

235

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

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

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

2015-05-01

236

Potentials and limitations of biomethane and phosphorus recovery from sludges of brackish/marine aquaculture recirculation systems: a review.  

PubMed

Brackish/marine recirculation aquaculture systems (RAS) produce a relatively small but concentrated waste stream. The produced waste is perceived as a constraint for sustainable development of brackish/marine RAS. Appropriate disposal of sludge or waste from brackish/marine RAS is of great importance for widespread acceptance and implementation. Anaerobic stabilization of RAS sludge is considered as a potential cost-effective methodology to achieve effective sludge reduction and biogas production. Therefore, this review presents an overview of studies conducted on anaerobic digestion of sludge from brackish/marine RAS. Several researchers have shown that specific methane yield (SMY) of anaerobic digestion of sludges from brackish/marine RAS is relatively low, mainly in the range of 0.001-0.184 m(3) CH4 (STP)/kg COD of sludge added. The possible reasons for low SMY are reviewed in this work and can be mainly attributed to applied experimental set-ups, particularly improper inoculum, and high salinity, mainly resulting from high sodium cation levels. This review also evaluates the potentials and limitations for phosphorus recovery from the waste streams. Additionally, corresponding approaches to enhance specific methanogenic activities are proposed, particularly about the need for further thickening sludges from brackish/marine RAS in order to increase SMY from the wastes and downsize the anaerobic digestion units. PMID:24140486

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

2013-12-15

237

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

E-print Network

of North Deer Island in W st Galveston Bay. Oyster clumps were scrubbed, rinsed with fresh water and separated into single oysters one day after collection. Clams (~Ran ia cuneata) were obtained from those in the tanks at the time the ex- periment...

Berry, Terri Layne

1978-01-01

238

Inland marine fish culture in low-salinity recirculating aquaculture systems  

Technology Transfer Automated Retrieval System (TEKTRAN)

Expansion of marine aquaculture is challenged by the high cost and limited availability of coastal land and water resources, effluent concerns, high production costs, restricted growing seasons, lack of quality seedstock, and inadequate regulatory and permitting processes. Many of these constraints...

239

Identification of conditions underlying production of geosmin and 2-methylisoborneol in a recirculating system  

Microsoft Academic Search

Geosmin and 2-methylisoborneol (MIB) are semi-volatile terpenoid compounds produced as secondary metabolites by benthic and planktonic cyanobacteria, several genera of fungi, and various actinomycetes. These off-flavor compounds pose a heavy economic burden in the aquaculture industry rendering fish unmarketable unless purified by purging with large quantities of clean water. In the present study, the presence of off-flavor compounds was examined

Lior Guttman; Jaap van Rijn

2008-01-01

240

Development of zooplankton culture subsystem for a closed ecological recirculating aquaculture system (CERAS)  

NASA Astrophysics Data System (ADS)

Ten parthenogenetic females of Moina macrocopa were placed in small cells with different flow conditions. The cells were opened after three-days of cultivation, and the water fleas in each cell were counted. It appeared that M. macrocopa were cultured effectively in a relatively slow current, 10 cm/min., but the population growth was not significantly influenced by the difference in flow direction. Subsequent, filtration efficiencies of filters with various pore sizes were compared. Four available porous hollow-fiber membrane modules, ACP-1010, AHP-1010, PSP-103, and PMP-102 (Asahi-Kasei Corp.), were tested. The module with the larger pore size initially filtered a greater amount of water but clogged up sooner. ACP-1010, which has the smallest pores, was considered to be suitable to filter condensed algal water due to its durability and stable filtration. An improved zooplankton culture device (IZCD) was designed and constructed based on these examinations. IZCD is a 13.2L airtight device characterized by a short and thick rearing tank and alternate filtration with paired fine hollow-fiber membrane modules. It must be tested and revised to be used in research into the optimal conditions for a zooplankton culture in a closed environment.

Omori, Katsunori; Oguchi, Mitsuo; Takeuchi, Toshio

2006-01-01

241

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

Microsoft Academic Search

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

Robert C. Summerfelt; Chris R. Penne

2005-01-01

242

Recirculating rotary gas compressor  

DOEpatents

A positive displacement, recirculating Roots-type rotary gas compressor is described which operates on the basis of flow work compression. The compressor includes a pair of large diameter recirculation conduits which return compressed discharge gas to the compressor housing, 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 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. 12 figs.

Weinbrecht, J.F.

1992-02-25

243

Effects of non-uniform root zone salinity on water use, Na+ recirculation, and Na+ and H+ flux in cotton  

PubMed Central

A new split-root system was established through grafting to study cotton response to non-uniform salinity. Each root half was treated with either uniform (100/100?mM) or non-uniform NaCl concentrations (0/200 and 50/150?mM). In contrast to uniform control, non-uniform salinity treatment improved plant growth and water use, with more water absorbed from the non- and low salinity side. Non-uniform treatments decreased Na+ concentrations in leaves. The [Na+] in the ‘0’ side roots of the 0/200 treatment was significantly higher than that in either side of the 0/0 control, but greatly decreased when the ‘0’ side phloem was girdled, suggesting that the increased [Na+] in the ‘0’ side roots was possibly due to transportation of foliar Na+ to roots through phloem. Plants under non-uniform salinity extruded more Na+ from the root than those under uniform salinity. Root Na+ efflux in the low salinity side was greatly enhanced by the higher salinity side. NaCl-induced Na+ efflux and H+ influx were inhibited by amiloride and sodium orthovanadate, suggesting that root Na+ extrusion was probably due to active Na+/H+ antiport across the plasma membrane. Improved plant growth under non-uniform salinity was thus attributed to increased water use, reduced leaf Na+ concentration, transport of excessive foliar Na+ to the low salinity side, and enhanced Na+ efflux from the low salinity root. PMID:22200663

Kong, Xiangqiang; Luo, Zhen; Dong, Hezhong; Eneji, A. Egrinya

2012-01-01

244

Exhaust gas recirculation apparatus  

SciTech Connect

An exhaust gas recirculation passageway leads from an engine exhaust passageway to an engine induction passageway downstream of a throttle valve. A fuel control member of an injection pump moves the throttle valve in the opening direction to reduce the vacuum in the induction passageway and thereby the amount of exhaust gas recirculation only when the fuel control member is moved beyond a predetermined position in the fuel increasing direction. A stopper limits movement of the throttle valve in the closing direction.

Wake, J.; Matsuda, H.

1980-01-01

245

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...

246

Establishment of a real-time PCR method for quantification of geosmin-producing Streptomyces spp. in recirculating aquaculture systems.  

PubMed

Geosmin and 2-methylisoborneol (MIB) have been associated with off-flavour problems in fish and seafood products, generating a strong negative impact for aquaculture industries. Although most of the producers of geosmin and MIB have been identified as Streptomyces species or cyanobacteria, Streptomyces spp. are thought to be responsible for the synthesis of these compounds in indoor recirculating aquaculture systems (RAS). The detection of genes involved in the synthesis of geosmin and MIB can be a relevant indicator of the beginning of off-flavour events in RAS. Here, we report a real-time polymerase chain reaction (qPCR) protocol targeting geoA sequences that encode a germacradienol synthase involved in geosmin synthesis. New geoA-related sequences were retrieved from eleven geosmin-producing Actinomycete strains, among them two Streptomyces strains isolated from two RAS. Combined with geoA-related sequences available in gene databases, we designed primers and standards suitable for qPCR assays targeting mainly Streptomyces geoA. Using our qPCR protocol, we succeeded in measuring the level of geoA copies in sand filter and biofilters in two RAS. This study is the first to apply qPCR assays to detect and quantify the geosmin synthesis gene (geoA) in RAS. Quantification of geoA in RAS could permit the monitoring of the level of geosmin producers prior to the occurrence of geosmin production. This information will be most valuable for fish producers to manage further development of off-flavour events. PMID:22060964

Auffret, Marc; Pilote, Alexandre; Proulx, Emilie; Proulx, Daniel; Vandenberg, Grant; Villemur, Richard

2011-12-15

247

Experience with molecular adsorbent recirculating system treatment in 20 children listed for high-urgency liver transplantation.  

PubMed

For more than 10 years, children at our national center for pediatric liver transplantation (LT) have been treated with Molecular Adsorbent Recirculating System (MARS) liver dialysis as a bridging therapy to high-urgency LT. Treatment was reserved for 20 patients with the highest degrees of hepatic encephalopathy (HE; median grade?=?3.5). Death from neurological sequelae was considered imminent for these patients, and this was further reflected in significantly higher international normalized ratios and ammonia levels and worse prognostic liver indices (Model for End-Stage Liver Disease/Pediatric End-Stage Liver Disease scores and liver injury units) in comparison with 32 wait-listed patients who did not receive MARS dialysis. MARS therapy was generally well tolerated, with a reduction in thrombocytes and hemorrhaging as the most common side effects. HE improvement was documented in 30% of the treated patients, but progression to grade IV encephalopathy occurred in 45% of the patients despite the treatment. Serum ammonia, bilirubin, bile acid, and creatinine levels significantly decreased during treatment. Eighty percent of MARS-treated patients survived to undergo LT, and their survival was equivalent to that of non-MARS-treated patients with severe liver failure (69%, P?=?0.52). The heterogeneity between MARS-treated patients and non-MARS-treated patients in our cohort precluded a statistical evaluation of a benefit from MARS for patient survival. Our data demonstrate the safety of MARS even in the most severely ill patients awaiting LT, but strategies that promote the more rapid and widespread availability of high-quality donor organs remain of critical importance for improving patient survival in cases of severe acute liver failure. PMID:25366362

Lexmond, Willem S; Van Dael, Carin M L; Scheenstra, René; Goorhuis, Joanne F; Sieders, Egbert; Verkade, Henkjan J; Van Rheenen, Patrick F; Kömhoff, Martin

2015-03-01

248

Systems and methods for reactive distillation with recirculation of light components  

DOEpatents

Systems and methods for producing gas-to-liquids products using reactive distillation are provided. The method for producing gas-to-liquids products can include reacting a feedstock in a column having a distillation zone and a reaction zone to provide a bottoms stream and an overhead stream. A first portion of the overhead stream can be recycled to the column at the top of the reaction zone and second portion of the overhead stream can be recycled to the column at the bottom of the reaction zone.

Stickney, Michael J. (Nassau Bay, TX); Jones, Jr., Edward M. (Friendswood, TX)

2011-07-26

249

Relevance of Nitrospira for nitrite oxidation in a marine recirculation aquaculture system and physiological features of a Nitrospira marina-like isolate.  

PubMed

In biofilters of recirculation aquaculture systems (RAS), nitrification by lithoautotrophic microorganisms is essential to prevent the cultivated organisms from intoxication with ammonium and nitrite. In moving-bed biofilters nitrifying microorganisms are immobilized together with heterotrophic bacteria in dense biofilms on carrier elements like plastic beads. Analyses of fatty acid profiles of these biofilms from a marine biofilter revealed a high abundance of Nitrospira-related lipid markers (8-12% of total fatty acids). Further results of a labeling experiment with (13) C-bicarbonate in mineral salts medium with 3 mM nitrite confirmed that Nitrospira is the major autotrophic nitrite oxidizer in the biofilter system. According to 16S rRNA gene sequence analyses the nitrite-oxidizing community in the biofilter consisted of at least two different representatives of Nitrospira, one of which could be successfully isolated. The marine isolate 'Ecomares 2.1' belongs to cluster IVa and showed 98.8% 16S rRNA gene sequence similarity to Nitrospira marina, whereas the enrichment 'M1 marine' is only distantly related (94.0% 16S rRNA gene sequence similarity to N. marina). In laboratory experiments, the isolate exhibited remarkable tolerances against high substrate and product concentrations (30 mM nitrite and 80 mM nitrate) as well as ammonium (50 mM). During the isolation process a strong tendency of this strain to develop biofilms became apparent. Thus, Ecomares 2.1 seems to be well adapted to the attached lifestyle in biofilters and the nitrogenous load prevailing in the effluent waters of RAS. Both members of Nitrospira could be detected by PCR-based methods in environmental samples of marine and brackish RAS biofilters and are therefore considered to be characteristic for these engineered ecosystems. PMID:21812886

Keuter, Sabine; Kruse, Myriam; Lipski, André; Spieck, Eva

2011-09-01

250

Effects of magnetic field on the antioxidant defense system of recirculation-cultured Chlorella vulgaris.  

PubMed

Little is known about the influence of magnetic fields (MF) on growth of microalgae such as Chlorella vulgaris, which has been consumed as health food for various nutritional and pharmacological effects. This preliminary study investigated whether static MF can modulate the antioxidant system in C. vulgaris by exposing the cells to static MF generated by dual yoke electromagnets with magnetic flux density of 10-50 mT for 12 h. After exposure to 10-35 mT for 12 h, the activity of superoxide dismutases and peroxidase increased significantly compared to control cells. However, a remarkable increase of catalase activity occurred at 45 and 50 mT. The lipid peroxidation of algae cells determined by production of thiobarbituric acid-reactive substances was much increased when exposed to 35, 45, and 50 mT of MF. The scavenging ability of 2,2-diphenyl-1-picrylhydrazyl radical was decreased markedly while there was no variation of total carotenoids content in C. vulgaris cells. Assay of specific growth rate in 72 h cultivation after MF exposure was also conducted. In groups after exposure to 10-35 mT of MF, specific growth rate was significantly increased. These results suggest that 10-35 mT of static MF exposure could promote the growth of C. vulgaris and regulate its antioxidant defense system to protect cells efficiently, which could possibly enhance the growth of C. vulgaris in industrialized cultivation by MF. PMID:17694535

Wang, Hai-Ying; Zeng, Xiao-Bo; Guo, Si-Yuan; Li, Zong-Tao

2008-01-01

251

Effect of diets containing gossypol on blood parameters and spleen structure in tilapia, Oreochromis sp., reared in a recirculating system.  

PubMed

The high cost of fish meal in tilapia diets warrants the potential use of cottonseed meal (CSM) as an alternative source of high quality protein. The effects of varying levels of CSM (0, 25, 50, 75 and 100%) as fish meal protein replacement on growth, blood parameters, spleen characteristics, free and bound gossypol in blood plasma, haemoglobin and haematocrit were determined in tilapia. Gossypol (C(30)H(30)O(8)) is a polyphenolic substance found in cottonseed that has known toxic effects in fish. Tilapias (n = 219, average weight = 11.3 +/- 3.9 g) were randomly distributed into 15, 32-L glass aquaria, representing five dietary treatments and three replicates per treatment. Each aquarium containing 13-16 fish was supplied with thermoregulated, recirculating water (27 +/- 1 degrees C) at 1 L min(-1) flow rate and photoperiod was constant (12 h L/12 h D). Fish fed 25-50% CSM protein replacement showed similar body weights and total lengths as the controls at the completion of the 16-week trial. Fish fed 75 and 100% CSM protein replacement showed a significant decline in body weight and total length. Fish fed 25-100% CSM protein replacement had significantly lower haematocrit and haemoglobin (ANOVA/LSD, P < 0.05) compared with levels in controls. The decline was most prominent in groups fed diets with 50-100% CSM protein replacement. Total and free gossypol concentrations of blood plasma significantly increased with increasing levels of CSM replacement (P < 0.05). No gossypol was found in blood plasma of fish from the control group. The occurrence of immature and abnormal erythrocytes was significantly greater among fish fed 75 and 100% CSM diets compared with fish fed 0-50% CSM diets. Spleen-somatic index (spleen weight/body weight x 100) did not differ between control fish and fish fed 50-100% CSM diets. Spleen abnormalities, such as large depositions of haemosiderin and melanin pigments and proliferation of melano-macrophage centres, lymphocytic depletion of the white pulp areas (hypocellularity), and presence of vacuoles and necrotic areas were observed among fish fed 50-100% CSM protein diets. In general, the pathological effects of gossypol in tilapia (low haemoglobin and haematocrit levels, abundance of immature red blood cells or polychromatocytes, abnormal spleen morphology) were similar to the effects of vitamin E and/or vitamin C deficiencies observed in other studies. PMID:15189376

Garcia-Abiado, M A; Mbahinzireki, G; Rinchard, J; Lee, K J; Dabrowski, K

2004-06-01

252

Containment system for supercritical water oxidation reactor  

DOEpatents

A system for containment of a supercritical water oxidation reactor in the event of a rupture of the reactor. The system includes a containment for housing the reaction vessel and a communicating chamber for holding a volume of coolant, such as water. The coolant is recirculated and sprayed to entrain and cool any reactants that might have escaped from the reaction vessel. Baffles at the entrance to the chamber prevent the sprayed coolant from contacting the reaction vessel. An impact-absorbing layer is positioned between the vessel and the containment to at least partially absorb momentum of any fragments propelled by the rupturing vessel. Remote, quick-disconnecting fittings exterior to the containment, in cooperation with shut-off valves, enable the vessel to be isolated and the system safely taken off-line. Normally-closed orifices throughout the containment and chamber enable decontamination of interior surfaces when necessary.

Chastagner, Philippe (3134 Natalie Cir., Augusta, GA 30909-2748)

1994-01-01

253

Containment system for supercritical water oxidation reactor  

DOEpatents

A system is described for containment of a supercritical water oxidation reactor in the event of a rupture of the reactor. The system includes a containment for housing the reaction vessel and a communicating chamber for holding a volume of coolant, such as water. The coolant is recirculated and sprayed to entrain and cool any reactants that might have escaped from the reaction vessel. Baffles at the entrance to the chamber prevent the sprayed coolant from contacting the reaction vessel. An impact-absorbing layer is positioned between the vessel and the containment to at least partially absorb momentum of any fragments propelled by the rupturing vessel. Remote, quick-disconnecting fittings exterior to the containment, in cooperation with shut-off valves, enable the vessel to be isolated and the system safely taken off-line. Normally-closed orifices throughout the containment and chamber enable decontamination of interior surfaces when necessary. 2 figures.

Chastagner, P.

1994-07-05

254

A computational and experimental study inside microfluidic systems: the role of shear stress and flow recirculation in cell docking.  

PubMed

In this paper, microfluidic devices containing microwells that enabled cell docking were investigated. We theoretically assessed the effect of geometry on recirculation areas and wall shear stress patterns within microwells and studied the relationship between the computational predictions and experimental cell docking. We used microchannels with 150 microm diameter microwells that had either 20 or 80 microm thickness. Flow within 80 microm deep microwells was subject to extensive recirculation areas and low shear stresses (<0.5 mPa) near the well base; whilst these were only presented within a 10 microm peripheral ring in 20 microm thick microwells. We also experimentally demonstrated that cell docking was significantly higher (p < 0.01) in 80 microm thick microwells as compared to 20 microm thick microwells. Finally, a computational tool which correlated physical and geometrical parameters of microwells with their fluid dynamic environment was developed and was also experimentally confirmed. PMID:20300857

Cioffi, Margherita; Moretti, Matteo; Manbachi, Amir; Chung, Bong Geun; Khademhosseini, Ali; Dubini, Gabriele

2010-08-01

255

Energy conservation by partial recirculation of peanut drying air  

SciTech Connect

Conventional, recirculating, and intermittent type peanut dryers were compared in a three-year study. Comparisons indicate that partial recirculation of peanut drying air may reduce energy consumption per unit of water removed by approximately 25% while also reducing required drying time and maintaining high quality.

Young, J.H.

1983-06-01

256

Residential hot water distribution systems: Roundtablesession  

SciTech Connect

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.

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

2002-08-01

257

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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 9.5 m3 WRAS, containing a single 5.3 m3 tank and operated at a total recirculating fl...

258

Microbiology of cooling water  

SciTech Connect

An overview of microbiology is given as related to recirculating cooling water systems. Discussions covering the types of microbes that infest cooling water systems, their effects on these systems, and factors influencing growth and health of the microbes are included. The procedures for microbiological control in recirculating cooling systems is also described, including the effects of process contaminants on microbes, commercial microbicides, and an account of biological oxidation processes and the factors for using effluents from these processes for cooling. (DLS)

McCoy, J.W.

1980-01-01

259

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

Federal Register 2010, 2011, 2012, 2013, 2014

...emergency core cooling, containment heat removal, or containment atmosphere cleanup systems. RG 1.82 provides guidelines for evaluating...emergency core cooling, containment heat removal, or containment atmosphere cleanup systems. RG 1.82 provides guidelines for...

2012-04-02

260

Application of reliability techniques to prioritize BWR (boiling water reactor) recirculation loop welds for in-service inspection  

Microsoft Academic Search

In January 1988 the US Nuclear Regulatory Commission issued Generic Letter 88-01 together with NUREG-0313, Revision 2, Technical Report on Material Selection and Processing Guidelines for BWR Coolant Pressure Boundary Piping,'' to implement NRC long-range plans for addressing the problem of stress corrosion cracking in boiling water reactor piping. NUREG-0313 presents guidelines for categorizing BWR pipe welds according to their

Holman

1989-01-01

261

Iodine and selenium supplementation increased survival and changed thyroid hormone status in Senegalese sole (Solea senegalensis) larvae reared in a recirculation system.  

PubMed

To test how iodine and both iodine and selenium supplementation affected the thyroid status as well as growth and survival in Senegalese sole, larvae were reared in a recirculation system from 15 to 34 DAH. Sets of three tanks were assigned to each of the following three diets: control (C), iodine (I) and iodine and selenium (I + Se). Samples were collected at 15, 27 and 34 DAH to determine dry weight, iodine and selenium levels, GPx and ORD activities, thyroid hormone levels and thyroid follicles histology. At 34 DAH, fish from the control (C) treatment suffered from hyperplasia of the thyroid follicles (goitre), whereas iodine-treated larvae did not (I and I + Se). Lower survival rates in the C groups were probably a consequence of the hyperplasia. Moreover, there was an improvement in thyroid hormone status in I- and I + Se-treated larvae, showing that further supplementation of live feed with iodine can be crucial for fish at early life stages, as it seems to sustain normal larval development, when reared in a recirculation system. Selenium did not affect the results. Together with previous results, this indicates selenium supplement is more important at younger life stages. PMID:21932022

Ribeiro, A R A; Ribeiro, L; Sæle, O; Dinis, M T; Moren, M

2012-06-01

262

A comparison of larval production of the northern scallop, Argopecten purpuratus, in closed and recirculating culture systems  

Microsoft Academic Search

Northern scallop Argopecten purpuratus aquaculture relies on an efficient all year-round larval supply. Larvae are generally produced in closed aquaculture systems (CAS) using the batch techniques with periodical water changes. For instance, survival rates are greatly variable and can range from 0 to 80% making production of scallop larvae uncertain. The main goal of this study was to determine the

Germán Merino; Eduardo Uribe; Gaspar Soria; Elisabeth von Brand

2009-01-01

263

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 ...

264

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

Microsoft Academic Search

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

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

265

Effect of Water pH on Yield and Nutritional Status of Greenhouse Cucumber Grown in Recirculating Hydroponics  

Microsoft Academic Search

Cucumbers are produced in integrated hydroponic and aquaculture systems (aquaponics). Aquaponics balances pH for plants, fish, and nitrifying bacteria. Nitrification prevents buildup of toxic waste ammonia by conversion to nitrate (NO3 - nitrogen (N). The pH for hydroponic cucumbers (5.5–6.0) and nitrification (7.5–9.0) requires reconciliation to improve systems integration. Cucumbers were grown at pH of 5.0, 6.0, 7.0, and 8.0

R. V. Tyson; E. H. Simonne; D. D. Treadwell; M. Davis; J. M. White

2008-01-01

266

Wash water recovery system  

NASA Technical Reports Server (NTRS)

The Wash Water Recovery System (WWRS) is intended for use in processing shower bath water onboard a spacecraft. The WWRS utilizes flash evaporation, vapor compression, and pyrolytic reaction to process the wash water to allow recovery of potable water. Wash water flashing and foaming characteristics, are evaluated physical properties, of concentrated wash water are determined, and a long term feasibility study on the system is performed. In addition, a computer analysis of the system and a detail design of a 10 lb/hr vortex-type water vapor compressor were completed. The computer analysis also sized remaining system components on the basis of the new vortex compressor design.

Deckman, G.; Rousseau, J. (editor)

1973-01-01

267

Economic values of growth and feed efficiency for fish farming in recirculating aquaculture system with density and nitrogen output limitations: a case study with African catfish (Clarias gariepinus).  

PubMed

In fish farming, economic values (EV) of breeding goal traits are lacking, even though they are key parameters when defining selection objectives. The aim of this study was to develop a bioeconomic model to estimate EV of 2 traits representing production performances in fish farming: the thermal growth coefficient (TGC) and the feed conversion ratio (FCR). This approach was applied to a farm producing African catfish (Clarias gariepinus) in a recirculating aquaculture system (RAS). In the RAS, 2 factors could limit production level: the nitrogen treatment capacity of the biofilter or the fish density in rearing tanks at harvest. Profit calculation includes revenue from fish sales, cost of juveniles, cost of feed, cost of waste water treatment, and fixed costs. In the reference scenario, profit was modeled to zero. EV were calculated as the difference in profit per kilogram of fish between the current population mean for both traits (µt) and the next generation of selective breeding (µt+?t) for either TGC or FCR. EV of TGC and FCR were calculated for three generations of hypothetical selection on either TGC or FCR (respectively 6.8% and 7.6% improvement per generation). The results show that changes in TGC and FCR can affect both the number of fish that can be stocked (number of batches per year and number of fish per batch) and the factor limiting production. The EV of TGC and FCR vary and depend on the limiting factors. When dissolved NH3-N is the limiting factor for both µt and µt+?t, increasing TGC decreases the number of fish that can be stocked but increases the number of batches that can be grown. As a result, profit remains constant and EVTGC is zero. Increasing FCR, however, increases the number of fish stocked and the ratio of fish produced per kilogram of feed consumed ("economic efficiency"). The EVFCR is 0.14 €/kg of fish, and profit per kilogram of fish increases by about 10%. When density is the limiting factor for both µt and µt+?t, the number of fish stocked per batch is fixed; therefore, extra profit is obtained by increasing either TGC, which increases the annual number of batches, or by decreasing FCR, which decreases annual feed consumption. EVTGC is 0.03 €/kg of fish and EVFCR is 0.05-0.06 €/kg of fish. These results emphasize the importance of calculating economic values in the right context to develop efficient future breeding programs in aquaculture. PMID:25414104

Besson, M; Komen, H; Aubin, J; de Boer, I J M; Poelman, M; Quillet, E; Vancoillie, C; Vandeputte, M; van Arendonk, J A M

2014-12-01

268

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

ERIC Educational Resources Information Center

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…

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

2008-01-01

269

Recirculating Air Filtration Significantly Reduces Exposure to Airborne Nanoparticles  

PubMed Central

Background Airborne nanoparticles from vehicle emissions have been associated with adverse effects in people with pulmonary and cardiovascular disease, and toxicologic studies have shown that nanoparticles can be more hazardous than their larger-scale counterparts. Recirculating air filtration in automobiles and houses may provide a low-cost solution to reducing exposures in many cases, thus reducing possible health risks. Objectives We investigated the effectiveness of recirculating air filtration on reducing exposure to incidental and intentionally produced airborne nanoparticles under two scenarios while driving in traffic, and while generating nanomaterials using gas-phase synthesis. Methods We tested the recirculating air filtration in two commercial vehicles when driving in traffic, as well as in a nonventilation room with a nanoparticle generator, simulating a nanomaterial production facility. We also measured the time-resolved aerosol size distribution during the in-car recirculation to investigate how recirculating air filtration affects particles of different sizes. We developed a recirculation model to describe the aerosol concentration change during recirculation. Results The use of inexpensive, low-efficiency filters in recirculation systems is shown to reduce nanoparticle concentrations to below levels found in a typical office within 3 min while driving through heavy traffic, and within 20 min in a simulated nanomaterial production facility. Conclusions Development and application of this technology could lead to significant reductions in airborne nanoparticle exposure, reducing possible risks to health and providing solutions for generating nanomaterials safely. PMID:18629306

Pui, David Y.H.; Qi, Chaolong; Stanley, Nick; Oberdörster, Günter; Maynard, Andrew

2008-01-01

270

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

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

271

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

SciTech Connect

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.

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

1993-08-01

272

Cooling Water Systems Module  

NSDL National Science Digital Library

The Center for the Advancement of Process Technology presents this free sample module on cooling water systems in the process industry. The material includes 21 slides and will help learners understand related terms, the purpose of the basic equipment involved in cooling water systems and the safety, health and environmental concerns involved with these systems.

273

Water Purification Systems  

NASA Technical Reports Server (NTRS)

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.

1992-01-01

274

Reactor water cleanup system  

DOEpatents

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.

Gluntz, Douglas M. (San Jose, CA); Taft, William E. (Los Gatos, CA)

1994-01-01

275

Reactor water cleanup system  

DOEpatents

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.

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

1994-12-20

276

SELECTED METABOLIC ASPECTS OF PIKEPERCH, STIZOSTEDION LUCIOPERCA (L.) REARED IN A WATER RECIRCULATION SYSTEM  

Microsoft Academic Search

The aim of the present study was to evaluate the effect of fish size (BW 11.7 g in the PS group, and 28.1 g in the PL group), feeding (SDA effect), and starvation (4, 13, 19 or 26 days in the PS-S group, and 4 or 13 days in the PL-S group) on oxygen consumption (OC ,m g O2 kg

Krystyna Demska-Zakêœ; Piotr Karczewski; Andrzej Karpiñski

277

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

Microsoft Academic Search

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

C. McGowin; M. DiFilippo; L. Weintraub

2006-01-01

278

Purge water management system  

DOEpatents

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.

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

1996-01-01

279

Purge water management system  

DOEpatents

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.

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

1995-01-01

280

Cooling water distribution system  

DOEpatents

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.

Orr, Richard (Pittsburgh, PA)

1994-01-01

281

Evaluating Domestic Hot Water Distribution System Options With Validated Analysis Models  

SciTech Connect

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.

Weitzel, E.; Hoeschele, M.

2014-09-01

282

Coke-free dry reforming of model diesel fuel by a pulsed spark plasma at low temperatures using an exhaust gas recirculation (EGR) system  

NASA Astrophysics Data System (ADS)

Dry reforming of diesel fuel, an endothermic reaction, is an attractive process for on-board hydrogen/syngas production to increase energy efficiency. For operating this dry reforming process in a vehicle, we can use the exhaust gas from an exhaust gas recirculation (EGR) system as a source of carbon dioxide. Catalytic dry reforming of heavy hydrocarbon is a very difficult reaction due to the high accumulation of carbon on the catalyst. Therefore, we attempted to use a non-equilibrium pulsed plasma for the dry reforming of model diesel fuel without a catalyst. We investigated dry reforming of model diesel fuel (n-dodecane) with a low-energy pulsed spark plasma, which is a kind of non-equilibrium plasma at a low temperature of 523 K. Through the reaction, we were able to obtain syngas (hydrogen and carbon monoxide) and a small amount of C2 hydrocarbon without coke formation at a ratio of CO2/Cfuel = 1.5 or higher. The reaction can be conducted at very low temperatures such as 523 K. Therefore, it is anticipated as a novel and effective process for on-board syngas production from diesel fuel using an EGR system.

Sekine, Yasushi; Furukawa, Naotsugu; Matsukata, Masahiko; Kikuchi, Eiichi

2011-07-01

283

Optimal mixing in recirculation zones  

Microsoft Academic Search

Coarse-scale mixing in a recirculation zone is described with a simple vortex model. Time-dependent forcing is employed to change the vortex motion and mixing properties. An optimal mixing problem is defined in which the flux across the recirculation region shall be maximized under the side-constraints of bounded vortex motion and bounded actuation. Concepts of control theory and chaotic advection are

Bernd R. Noack; Igor Mezic; Gilead Tadmor; Andrzej Banaszuk

2004-01-01

284

Recirculation of municipal landfill leachate  

E-print Network

RECIRCULATION OF MUNICIPAL LANDFILL LEACHATE A Thesis by BRIAN JUDE PINKO4ISKI Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1987 Major Subject...: Civil Engineering RECIRCULATION OF MUNICIPAL LANDFILL LEACHATE A Thesis by BRIAN JUDE PINKOWSKI Approved as to style and content by: Charles P. Giammona (Chair of Committee) Roy . Harm, (Member) Kirk W. Brown (Member) Donald A. Maxwel...

Pinkowski, Brian Jude

1987-01-01

285

Operating experience of natural circulation core cooling in boiling water reactors  

Microsoft Academic Search

General Electric (GE) has proposed an advanced boiling water reactor, the Simplified Boiling Water Reactor (SBWR), which will utilize passive, gravity-driven safety systems for emergency core coolant injection. The SBWR design includes no recirculation loops or recirculation pumps. Therefore the SBWR will operate in a natural circulation (NC) mode at full power conditions. This design poses some concerns relative to

C. Kullberg; K. Jones; C. Heath

1993-01-01

286

Heat recirculating cooler for fluid stream pollutant removal  

DOEpatents

A process by which heat is removed from a reactant fluid to reach the operating temperature of a known pollutant removal method and said heat is recirculated to raise the temperature of the product fluid. The process can be utilized whenever an intermediate step reaction requires a lower reaction temperature than the prior and next steps. The benefits of a heat-recirculating cooler include the ability to use known pollutant removal methods and increased thermal efficiency of the system.

Richards, George A. (Morgantown, WV); Berry, David A. (Morgantown, WV)

2008-10-28

287

Northern boundary currents and adjacent recirculations off southwestern Australia  

NASA Astrophysics Data System (ADS)

Full-depth hydrographic and velocity measurements along 115°E south of Australia (WHP section I9S) reveal an active northern boundary current regime within 200-300 km of the Australian continental shelf and an offshore recirculation regime within the South Australian Basin. In the upper ocean an oft-described westward-flowing northern boundary current, the Flinders Current, extends through the thermocline and the salinity minimum strata of Antarctic Intermediate Water, with an opposing eastward recirculation to its south. The new data shows that beneath the Flinders Current, an eastward-flowing deep northern boundary current transports water of subtropical Indian Ocean origin supplied by southward deep flow along the western continental slope of Australia in the Perth Basin. Between these northern boundary currents and the Antarctic Circumpolar Current, thermocline and deep geostrophic shears indicate weak recirculations, eastward at thermocline levels and westward in the deep water. Lowered Acoustic Doppler current profiler data reveal stronger organized recirculations to both the Flinders Current and the deep northern boundary current, with the westward deep recirculation exceeding the eastward transport of the deep northern boundary current and thus representing a net supply of deep water to the Perth Basin.

Hufford, Gwyneth E.; McCartney, Michael S.; Donohue, Kathleen A.

1997-11-01

288

Water system virus detection  

NASA Technical Reports Server (NTRS)

The performance of a waste water reclamation system is monitored by introducing a non-pathogenic marker virus, bacteriophage F2, into the waste-water prior to treatment and, thereafter, testing the reclaimed water for the presence of the marker virus. A test sample is first concentrated by absorbing any marker virus onto a cellulose acetate filter in the presence of a trivalent cation at low pH and then flushing the filter with a limited quantity of a glycine buffer solution to desorb any marker virus present on the filter. Photo-optical detection of indirect passive immune agglutination by polystyrene beads indicates the performance of the water reclamation system in removing the marker virus. A closed system provides for concentrating any marker virus, initiating and monitoring the passive immune agglutination reaction, and then flushing the system to prepare for another sample.

Fraser, A. S.; Wells, A. F.; Tenoso, H. J. (inventors)

1978-01-01

289

Cooling Water System Optimization  

E-print Network

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...

Aegerter, R.

2005-01-01

290

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)

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.

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

2015-01-01

291

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

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.

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

2004-01-01

292

Automatic hot water recovery system  

Microsoft Academic Search

Heat in the hot water lines of a water system is automatically recovered by providing a bridge conduit between the cold water lines and the hot water lines and by depressurizing the hot water lines relative to the cold water lines thereby to automatically direct higher pressure cold water into the hot water lines through the interconnection, which preferably is

Haws

1982-01-01

293

Dynamics of microorganism populations in recirculating nutrient solutions  

NASA Technical Reports Server (NTRS)

This overview covers the basic microbial ecology of recirculating hydroponic solutions. Examples from NASA and Soviet Controlled Ecological Life Support Systems (CELSS) tests and the commercial hydroponic industry will be used. The sources of microorganisms in nutrient solutions include air, water, seeds, plant containers and plumbing, biological vectors, and personnel. Microbial fates include growth, death, and emigration. Important microbial habitats within nutrient delivery systems are root surfaces, hardware surfaces (biofilms), and solution suspension. Numbers of bacteria on root surfaces usually exceed those from the other habitats by several orders of magnitude. Gram negative bacteria dominate the microflora with fungal counts usually much lower. Trends typically show a decrease in counts with increasing time unless stressed plants increase root exudates. Important microbial activities include carbon mineralization and nitrogen transformations. Important detrimental interactions include competition with plants, and human and plant pathogenesis.

Strayer, R. F.

1994-01-01

294

Solar heating and hot water system installed at Arlington Raquetball Club, Arlington, Virginia  

NASA Technical Reports Server (NTRS)

A solar space and water heating system is described. The solar energy system consists of 2,520 sq. ft. of flat plate solar collectors and a 4,000 gallon solar storage tank. The transfer medium in the forced closed loop is a nontoxic antifreeze solution (50 percent water, 50 percent propylene glycol). The service hot water system consists of a preheat coil (60 ft. of 1 1/4 in copper tubing) located in the upper third of the solar storage tank and a recirculation loop between the preheat coil and the existing electric water heaters. The space heating system consists of two separate water to air heat exchangers located in the ducts of the existing space heating/cooling systems. The heating water is supplied from the solar storage tank. Extracts from site files, specification references for solar modifications to existing building heating and hot water systems, and installation, operation and maintenance instructions are included.

1981-01-01

295

Solar heating and hot water system installed at Arlington Raquetball Club, Arlington, Virginia  

NASA Astrophysics Data System (ADS)

A solar space and water heating system is described. The solar energy system consists of 2,520 sq. ft. of flat plate solar collectors and a 4,000 gallon solar storage tank. The transfer medium in the forced closed loop is a nontoxic antifreeze solution (50 percent water, 50 percent propylene glycol). The service hot water system consists of a preheat coil (60 ft. of 1 1/4 in copper tubing) located in the upper third of the solar storage tank and a recirculation loop between the preheat coil and the existing electric water heaters. The space heating system consists of two separate water to air heat exchangers located in the ducts of the existing space heating/cooling systems. The heating water is supplied from the solar storage tank. Extracts from site files, specification references for solar modifications to existing building heating and hot water systems, and installation, operation and maintenance instructions are included.

1981-05-01

296

Research on the contact-impact between balls and re-circulating mechanism using the multibody dynamics simulation  

Microsoft Academic Search

The re-circulating mechanism of ball screws plays a vital role for its providing the path for steel balls rolling in screw grooves generally in high-speed\\/high-precision ball screw transmitting systems. However it is very hard to directly measure the ball's motion in the re-circulation for the closed recirculation groove. In order to investigate the impact-contact between the balls and re-circulating mechanism,

Hongkui Jiang; Xianchun Song; Wencheng Tang; Xiangrong Xu; Chengrui Zhang

2010-01-01

297

Validation for a recirculation model.  

PubMed

Recent Clean Air Act regulations designed to reduce volatile organic compound (VOC) emissions have placed new restrictions on painting operations. Treating large volumes of air which contain dilute quantities of VOCs can be expensive. Recirculating some fraction of the air allows an operator to comply with environmental regulations at reduced cost. However, there is a potential impact on employee safety because indoor pollutants will inevitably increase when air is recirculated. A computer model was developed, written in Microsoft Excel 97, to predict compliance costs and indoor air concentration changes with respect to changes in the level of recirculation for a given facility. The model predicts indoor air concentrations based on product usage and mass balance equations. This article validates the recirculation model using data collected from a C-130 aircraft painting facility at Hill Air Force Base, Utah. Air sampling data and air control cost quotes from vendors were collected for the Hill AFB painting facility and compared to the model's predictions. The model's predictions for strontium chromate and isocyanate air concentrations were generally between the maximum and minimum air sampling points with a tendency to predict near the maximum sampling points. The model's capital cost predictions for a thermal VOC control device ranged from a 14 percent underestimate to a 50 percent overestimate of the average cost quotes. A sensitivity analysis of the variables is also included. The model is demonstrated to be a good evaluation tool in understanding the impact of recirculation. PMID:11318387

LaPuma, P T

2001-04-01

298

Safety system consideration of a supercritical-water cooled fast reactor with simplified PSA  

Microsoft Academic Search

The probabilistic safety of the supercritical-water cooled fast reactor (SCFR) is evaluated with the simplified probabilistic safety assessment (PSA) methodology. SCFR has a once-through direct cycle where all feedwater flows through the core to the turbine at supercritical pressure. There are no recirculation loops in the once-through direct cycle system, which is the most important difference from the current light

J. H Lee; Y Oka; S Koshizuka

1999-01-01

299

Equilibrium solubility of carbon dioxide in the amine solvent system of (triethanolamine + piperazine + water)  

Microsoft Academic Search

In this study, a new set of data for the equilibrium solubility of carbon dioxide in the amine solvent system that consists of triethanolamine (TEA), piperazine (PZ), and water is presented. Equilibrium solubility values were obtained at T=(313.2, 333.2, and 353.2)K and pressures up to 153kPa using the vapour-recirculation equilibrium cell. The TEA concentrations in the considered ternary (solvent) mixture

Pei-Yuan Chung; Allan N. Soriano; Rhoda B. Leron; Meng-Hui Li

2010-01-01

300

Water Purification Systems  

NASA Technical Reports Server (NTRS)

Clearwater Pool Technologies employs NASA-developed silver/copper ionization to purify turtle and dolphin tanks, cooling towers, spas, water recycling systems, etc. The pool purifier consists of a microcomputer to monitor water conditions, a pair of metallic electrodes, and a rheostat controller. Ions are generated by passing a low voltage current through the electrodes; the silver ions kill the bacteria, and the copper ions kill algae. This technology has found broad application because it offers an alternative to chemical disinfectants. It was originally developed to purify water on Apollo spacecraft. Caribbean Clear has been using NASA's silver ionization technology for water purification for more than a decade. Two new products incorporate advancements of the basic technology. One is the AquaKing, a system designed for areas with no source of acceptable drinking water. Another is the Caribbean Clear Controller, designed for commercial pool and water park applications where sanitizing is combined with feedback control of pH and an oxidizer, chlorine or bromine. The technology was originally developed to purify water on Apollo spacecraft.

1994-01-01

301

Automatic hot water recovery system  

Microsoft Academic Search

A heat recovery system recovers hot water to an insulated tank through reciprocally variable volume chambers which are biased to draw water from hot water lines when the pressure throughout the system is equalized. One-way valving means permits continuous water flow when desired through the hot water tank to the hot water outlet. In a specific embodiment, bias is effected

Haws

1985-01-01

302

Identification and origin of plant pathogenic microorganisms in recirculating nutrient solutions.  

PubMed

Avoidance of root-infecting microorganisms was originally considered one of the advantages of cultivation of crops in a soilless, recirculating nutrient solution. However, to date, four viral, three bacterial and 21 fungal pathogens have been identified as causal agents of root disease in hydroponically-grown crops. Root-infecting fungi, particularly those which produce a motile stage known as a zoospore, have been the primary pathogens associated with extensive crop losses. Documented sources of these root pathogens in hydroponic systems include peat, surface water such as rivers and streams, and insects. The severity of disease caused by these introduced root pathogens is primarily governed by the genetic susceptibility of each crop and the temperature of the recirculating nutrient solution. PMID:11540205

Stanghellini, M E; Rasmussen, S L

1994-11-01

303

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

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.

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

2014-01-01

304

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

NASA Technical Reports Server (NTRS)

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.

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

2014-01-01

305

Development of a Vertical Recirculation Well System for the A/M Area of the Savannah River Site  

SciTech Connect

The objective of this work is to examine and develop a remediation scenario to provide long term hydraulic control and remediation of the dissolved chlorinated solvent plume within the Western and Southern Sectors of the A/M Area. This scope includes the development and siting of a remediation system that will contain the 500 part per billion trichloroethylene isoconcentration contour within each sector.

Jackson, D.G. Jr. [Westinghouse Savannah River Company, AIKEN, SC (United States); Looney, B.B.

1996-09-13

306

Dynamics of microorganism populations in recirculating nutrient solutions  

NASA Technical Reports Server (NTRS)

This overview covers the basic microbial ecology of recirculating hydroponic solutions. Examples from NASA and Soviet CELSS tests and the commercial hydroponic industry will be used. The sources of microorganisms in nutrient solutions include air, water, seeds, plant containers and plumbing, biological vectors, and personnel. Microbial fates include growth, death, and emigration. Important microbial habitats within nutrient delivery systems are root surfaces, hardware surfaces (biofilms), and solution suspension. Numbers of bacteria on root surfaces usually exceed those from the other habitats by several orders of magnitude. Gram negative bacteria dominate the microflora with fungal counts usually much lower. Trends typically show a decrease in counts with increasing time unless stressed plants increase root exudates. Important microbial activities include carbon mineralization and nitrogen transformations. Important detrimental interactions include competition with plants, and human and plant pathogenesis.

Strayer, R. F.

1994-01-01

307

Recycling crop residues for use in recirculating hydroponic crop production  

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

308

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

Microsoft Academic Search

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

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

2005-01-01

309

Water system virus detection  

NASA Technical Reports Server (NTRS)

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.

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

1975-01-01

310

Water and River Systems  

NSDL National Science Digital Library

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.

Timothy Heaton

311

Automatic water heater systems  

Microsoft Academic Search

A heat trap is described which can be connected to the flue exhaust outlet of an automatic gas water heating system in which heat can be entrapped that would otherwise be lost via hot flue gases passing up through the flue exhaust and out of a chimney. The heat trap comprises a tank containing therein vertically extending serpentine heat tubes.

R. O. Jr

1987-01-01

312

Green Systems Solar Hot Water  

E-print Network

Thermal Panels (Trex enclosure) Hot Water Storage Tank (TS-5; basement) Hot Water Heaters (HW-1Green Systems Solar Hot Water Heating the Building Co-generation: Heat Recovery System: Solar,2; basement) Pre-heats water so water heaters don't need to use as much energy Gas-powered, high efficiency

Schladow, S. Geoffrey

313

Water resource systems group  

NASA Astrophysics Data System (ADS)

The 11th meeting of the Water Resource Systems Group was held at the University of Washington (Seattle), August 7-8, 1987. These systems group meetings, which are informal gatherings of professionals who have an interest in the educational and research aspects of water resources systems analysis, have usually been held on university campuses. The 30 attendees of the 1987 meeting represented a cross section of university faculty and graduate students, government managers and researchers, and engineering consultants.The meeting opened with short discussions by Steve Burges (University of Washington), Chuck Howard (CDD Howard and Associates, Victoria, Canada), David Dawdy (consultant, San Francisco, Calif.), and Jon Liebman (University of Illinois, Urbana) outlining their views of current issues in the water resources area. Burges emphasized the limitations and inadequacies of many of the models currently used in hydrology: rainfall runoff models may not adequately capture the physical characteristics of the movement of water into channels, vadose and saturated zone pollutant transport models are incapable of reproducing many of the features observed in the field, and many streamflow forecasting models used for reservoir operations have been constructed to reproduce average conditions but break down under the extreme conditions (floods and droughts) where they are most needed.

Stedinger, Jery R.; Lettenmaier, Dennis P.

314

Variable Flow Chilled Water Systems  

E-print Network

Today, substantial savings can be achieved by converting constant flow-rate chilled water systems to variable flow-rate systems. This conversion is best suited for large, central plant chilled water systems where two or more chillers are utilized...

Baldwin, D. A.

315

Remote water monitoring system  

NASA Technical Reports Server (NTRS)

A remote water monitoring system is described that integrates the functions of sampling, sample preservation, sample analysis, data transmission and remote operation. The system employs a floating buoy carrying an antenna connected by lines to one or more sampling units containing several sample chambers. Receipt of a command signal actuates a solenoid to open an intake valve outward from the sampling unit and communicates the water sample to an identifiable sample chamber. Such response to each signal receipt is repeated until all sample chambers are filled in a sample unit. Each sample taken is analyzed by an electrochemical sensor for a specific property and the data obtained is transmitted to a remote sending and receiving station. Thereafter, the samples remain isolated in the sample chambers until the sampling unit is recovered and the samples removed for further laboratory analysis.

Grana, D. C.; Haynes, D. P. (inventors)

1978-01-01

316

Smart Water: Energy-Water Optimization in Drinking Water Systems  

EPA Science Inventory

This project aims to develop and commercialize a Smart Water Platform ? Sensor-based Data-driven Energy-Water Optimization technology in drinking water systems. The key technological advances rely on cross-platform data acquisition and management system, model-based real-time sys...

317

Extracorporeal detoxification for hepatic failure using molecular adsorbent recirculating system: depurative efficiency and clinical results in a long-term follow-up.  

PubMed

Acute liver failure and acute-on-chronic liver failure still show a poor prognosis. The molecular adsorbent recirculating system (MARS) has been extensively used as the most promising detoxifying therapy for patients with these conditions. Sixty-four patients with life-threatening liver failure were selected, and 269 MARS treatments were carried out as a bridge for orthotopic liver transplantation (OLT) or for liver function recovery. All patients were grouped according to the aim of MARS therapy. Group A consisted of 47 patients treated for liver function recovery (median age 59 years, range 23-82). Group B consisted of 11 patients on the waiting list who underwent OLT (median age 47 years, range 32-62). Group C consisted of 6 patients on the waiting list who did not undergo OLT (median age 45.5 years, range 36-54, P?=?0.001). MARS depurative efficiency in terms of liver toxins, cytokines, and growth factors was assessed together with the clinical outcome of the patients during a 1-year follow-up. Total bilirubin reduction rate per session (RRs) for each MARS session was 23% (range 17-29); direct bilirubin RRs was 28% (21-35), and indirect bilirubin RRs was 8% (3-21). Ammonia RRs was 34% (12-86). Conjugated cholic acid RRs was 58% (48-61); chenodeoxycholic acid RRs was 34% (18-48). No differences were found between groups. Hepatocyte growth factor (HGF) values on starting MARS were 4.1?ng/mL (1.9-7.9) versus 7.9?ng/mL (3.2-14.1) at MARS end (P?

Donati, Gabriele; La Manna, Gaetano; Cianciolo, Giuseppe; Grandinetti, Valeria; Carretta, Elisa; Cappuccilli, Maria; Panicali, Laura; Iorio, Mario; Piscaglia, Fabio; Bolondi, Luigi; Colì, Luigi; Stefoni, Sergio

2014-02-01

318

AN AUTOMATIC WATER DEAERATION SYSTEM  

Microsoft Academic Search

An automatic water deaeration system was designed and fabricated to ; provide a continuous supply of deaired water for fluid flow through porous media ; studies. Air is removed from the water by applying a vacuum on a tank while ; water is being sprayed into the tank. The system incorporates liquid level ; controls for the deairing and storage

1959-01-01

319

Water in the Solar System  

Microsoft Academic Search

Water is ubiquitous in the Universe, and also in the Solar System. By setting the snow line at its condensation level in the protosolar disk, water was responsible for separating the planets into the terrestrial and the giant ones. Water ice is a major constituent of the comets and the small bodies of the outer Solar System, and water vapor

Thérèse Encrenaz

2008-01-01

320

DOGBONE GEOMETRY FOR RECIRCULATING ACCELERATORS.  

SciTech Connect

Most scenarios for accelerating muons require recirculating acceleration. A racetrack shape for the accelerator requires particles with lower energy in early passes to traverse almost the same length of arc as particles with the highest energy. This extra arc length may lead to excess decays and excess cost. Changing the geometry to a dogbone shape, where there is a single linac and the beam turns completely around at the end of the linac, returning to the same end of the linac from which it exited, addresses this problem. In this design, the arc lengths can be proportional to the particle's momentum. This paper proposes an approximate cost model for a recirculating accelerator, attempts to make cost-optimized designs for both racetrack and dogbone geometries, and demonstrates that the dogbone geometry does appear to be more cost effective.

BERG,J.S.; JOHNSTONE,C.; SUMMERS,D.

2001-06-18

321

Optimization of Chilled Water Systems  

E-print Network

OPTIMIZATION OF CHILLED WATER SYSTEMS central 0 e m a In 8. N. Gidwani, P.E. Project Director Roy F. Weston, Inc. West Chester. Pennsylvania 19380 ABSTRACT Chilled water systems are one of the major energy consumers in industrial...

Gidwani, B. N.

1984-01-01

322

Digital feedwater and recirculation flow control for GPUN Oyster Creek  

Microsoft Academic Search

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

D. Burjorjee; B. Gan

1992-01-01

323

CLOSED-CYCLE WATER-BOILER REACTOR  

Microsoft Academic Search

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

1962-01-01

324

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

SciTech Connect

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).

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

325

10 Commercially Feasible Urban Recirculating Aquaculture: Addressing the Marine Sector  

Microsoft Academic Search

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

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

326

Nitrification in Drinking Water Systems  

Microsoft Academic Search

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

Yan Zhang; Nancy Love; Marc Edwards

2009-01-01

327

Compromise between ventilation, filtration strategies and recirculation rates for the design and operation of air-conditioned facilities in the tropics  

Microsoft Academic Search

This study examines the impact of filtration, ventilation and recirculation rate on concentration of condensed-phase, ozone (of outdoor origin)-derived oxidation products (secondary organic aerosols (SOA)) in a model room with a ventilation system that recirculates a large percentage (90%) of its supply air. Additionally, it critically evaluates the potential approach for filtering recirculated air and also avoiding the negative consequence

Moshood Olawale Fadeyi

2012-01-01

328

Automated Water-Purification System  

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

329

Fant's Grove Water System Clemson, SC  

E-print Network

in this report labeled Duke Power Water System Water Quality Table. Water Source The Fant's Grove Water System1 Fant's Grove Water System Clemson, SC 2001 Annual Water-Quality Report Clemson University water. We test our water using sophisticated equipment and advanced procedures. The water supplied

Duchowski, Andrew T.

330

Evacuated-Tube Heat-Pipe Solar Collectors Applied to the Recirculation Loop in a Federal Building: Preprint  

SciTech Connect

This paper describes the design, simulation, construction, and initial performance of a solar water heating system (a 360-tube evacuated-tube heat-pipe solar collector, 54 m2 in gross area, 36 m2 in net absorber area) installed at the top of the hot water recirculation loop in the Social Security Administration's Mid-Atlantic Center in Philadelphia. When solar energy is available, water returning to the hot water storage tank is heated by the solar array. This new approach, in contrast to the more conventional approach of preheating incoming water, is made possible by the thermal diode effect of heat pipes and low heat loss from evacuated-tube solar collectors. The simplicity of this approach and its low installation costs support the deployment of solar energy in existing commercial buildings, especially where the roof is some distance away from the water heating system, which is often in the basement. Initial performance measurements of the system are reported.

Walker, A.; Mahjouri, F.; Stiteler, R.

2004-06-01

331

Energy conserving water heating system  

SciTech Connect

Incoming cold water is delivered to a storage tank upstream from the customary domestic hot water heater. Waste heat recovery coils are located in the furnace flue and on the outlet of an air conditioning condenser unit. A system pump upstream from the water heater and between it and the storage tank circulates water from the storage tank through the two coils and back into the water inlet line leading to the water heater in a preheated state enabling the thermostatic setting of the water heater to be set at a significantly lower level than is customary.

Fleetwood, A.R.; Murphy, J.

1980-12-30

332

33 CFR 159.127 - Safety coliform count: Recirculating devices.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Safety coliform count: Recirculating devices. 159...and Testing § 159.127 Safety coliform count: Recirculating devices. ...recirculating device must have less than 240 fecal coliform bacteria per 100 milliliters....

2010-07-01

333

Industrial Energy Conservation, Forced Internal Recirculation Burner  

SciTech Connect

The overall objective of this research project is to develop and evaluate an industrial low NOx burner for existing and new gas-fired combustion systems for intermediate temperature (1400 degree to 2000 degree F) industrial heating devices such as watertube boilers and process fluid heaters. A multi-phase effort is being pursued with decision points to determine advisability of continuance. The current contract over Phases II and III of this work. The objectives of each phase are as follows. Phase II - to design, fabricate, and evaluate prototype burners based on the Forced Internal Recirculation (FIR) concept. Phase III - to evaluate the performance of an FIR burner under actual operating conditions in a full-scale field test and establish the performance necessary for subsequent commercialization

Joseph Rabovitser

2003-06-19

334

Outdoor Laboratory Water System Clemson, SC  

E-print Network

in this report labeled Duke Power Water System Water Quality Table. Water Source The Outdoor Laboratory Water = Nephelometric Turbidity Units #12;2 Duke Power Water System Water Quality Table Contaminant Date Tested Unit MCL1 Outdoor Laboratory Water System Clemson, SC 1999 Annual Water-Quality Report Clemson University

Duchowski, Andrew T.

335

Outdoor Laboratory Water System Clemson, SC  

E-print Network

in this report labeled Duke Power Water System Water Quality Table. Water Source The Outdoor Laboratory Water = Nephelometric Turbidity Units #12;2 Duke Power Water System Water Quality Table Contaminant Date Tested Unit MCL1 Outdoor Laboratory Water System Clemson, SC 2000 Annual Water-Quality Report Clemson University

Duchowski, Andrew T.

336

Flow field in the wake of a bluff body driven through a steady recirculating flow  

NASA Astrophysics Data System (ADS)

The wake produced by a bluff body driven through a steady recirculating flow is studied experimentally in a water facility using particle image velocimetry. The bluff body has a rectangular cross section of height, , and width, , such that the aspect ratio, AR = H/ D, is equal to 3. The motion of the bluff body is uniform and rectilinear, and corresponds to a Reynolds number based on width, Re D = 9,600. The recirculating flow is confined within a hemicylindrical enclosure and is generated by planar jets emanating from slots of width, , such that . Under these conditions, experiments are performed in a closed-loop facility that enables complete optical access to the near-wake. Velocity fields are obtained up to a distance of downstream of the moving body. Data include a selection of phase-averaged velocity fields representative of the wake for a baseline case (no recirculation) and an interaction case (with recirculation). Results indicate that the transient downwash flow typically observed in wakes behind finite bodies of small aspect ratio is significantly perturbed by the recirculating flow. The wake is displaced from the ground plane and exhibits a shorter recirculation zone downstream of the body. In summary, it was found that the interaction between a bluff body wake and a recirculating flow pattern alters profoundly the dynamics of the wake, which has implications on scalar transport in the wake.

Poussou, Stephane B.; Plesniak, Michael W.

2015-02-01

337

Hot water supply system  

Microsoft Academic Search

A novel pulse combustion water heater is compact in size and less noisy than previous models. The pulse combustor, suction muffler, blower, and exhaust muffler are all located at the lower portion of the storage tank, making it compact and easy to soundproof. The exhaust pipe extends to the top of the tank to heat the water, then descends back

M. Sakamoto; T. Saito

1984-01-01

338

Solar hot-water system  

NASA Technical Reports Server (NTRS)

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.

1979-01-01

339

Water Treatment Technology - Distribution Systems.  

ERIC Educational Resources Information Center

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…

Ross-Harrington, Melinda; Kincaid, G. David

340

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...

341

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

PubMed

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

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

2014-04-01

342

Hot water supply system  

SciTech Connect

A novel pulse combustion water heater is compact in size and less noisy than previous models. The pulse combustor, suction muffler, blower, and exhaust muffler are all located at the lower portion of the storage tank, making it compact and easy to soundproof. The exhaust pipe extends to the top of the tank to heat the water, then descends back into the soundproofed base to discharge the condensed flue gases.

Sakamoto, M.; Saito, T.

1984-05-22

343

Water Supply Infrastructure System Surety  

SciTech Connect

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.

EKMAN,MARK E.; ISBELL,DARYL

2000-01-06

344

Operational Management System for Regulated Water Systems  

NASA Astrophysics Data System (ADS)

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.

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

2012-04-01

345

Cyclone reactor with internal separation and axial recirculation  

DOEpatents

A cyclone combustor apparatus contains a circular partition plate containing a central circular aperture is described. 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 combustor 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 may be tangentially withdrawn from the outlet end 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. 10 figs.

Becker, F.E.; Smolensky, L.A.

1988-07-19

346

Research on leachate recirculation from different types of landfills  

SciTech Connect

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.

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

347

TANK MIXING STUDY WITH FLOW RECIRCULATION  

SciTech Connect

The primary objective of this work is to quantify the mixing time when two miscible fluids are mixed by one recirculation pump and to evaluate adequacy of 2.5 hours of pump recirculation to be considered well mixed in SRS tanks, JT-71/72. The work scope described here consists of two modeling analyses. They are the steady state flow pattern analysis during pump recirculation operation of the tank liquid and transient species transport calculations based on the initial steady state flow patterns. The modeling calculations for the mixing time are performed by using the 99% homogeneity criterion for the entire domain of the tank contents.

Lee, S.

2014-06-25

348

Lattice Design for the LHEC Recirculating Linac  

SciTech Connect

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.

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

2011-05-20

349

Gas turbine combustor stabilization by heat recirculation  

NASA Technical Reports Server (NTRS)

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.

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

1975-01-01

350

Biological flocculation treatment on distillery wastewater and recirculation of wastewater.  

PubMed

In the present study, a wastewater treatment system for the ethanol fermentation industry was developed by recycling distillery wastewater. The waste was able to be recycled for the next fermentation after being treated with bio-flocculation process. The bio-flocculation process contains three steps: screening, treatment with polyaspartic acid and filtration. When the filtrate from this process was recycled, the average ethanol production yield was very close to that in the conventional process using tap water. In contrast, the recycle of wastewater without flocculation and with chemical flocculation showed negative effects on ethanol yield as recycling was repeated. This new process was confirmed to have stable operation over ten recycles. Hazardous materials influencing distillery wastewater recycles on fermentation were also considered. It was found that the content of suspended solids (SS), volatile acid and Fe ions inhibited fermentation and resulted in a decreased ethanol yield. Bio-flocculation was shown to be an effective way to diminish the content of inhibitory compounds drastically when the waste was recirculated. PMID:19717237

Zhang, Wen; Xiong, Rongchun; Wei, Gang

2009-12-30

351

The Exploration Water Recovery System  

NASA Technical Reports Server (NTRS)

The Exploration Water Recovery System is designed towards fulfillment of NASA s Vision for Space Exploration, which will require elevation of existing technologies to higher levels of optimization. This new system, designed for application to the Exploration infrastructure, presents a novel combination of proven air and water purification technologies. The integration of unit operations is modified from that of the current state-of-the-art water recovery system so as to optimize treatment of the various waste water streams, contaminant loads, and flow rates. Optimization is achieved primarily through the removal of volatile organic contaminants from the vapor phase prior to their absorption into the liquid phase. In the current state-of-the-art system, the water vapor in the cabin atmosphere is condensed, and the volatile organic contaminants present in that atmosphere are absorbed into the aqueous phase. Removal of contaminants the5 occurs via catalytic oxidation in the liquid phase. Oxidation kinetics, however, dictate that removal of volatile organic contaminants from the vapor phase can inherently be more efficient than their removal from the aqueous phase. Taking advantage of this efficiency reduces the complexity of the water recovery system. This reduction in system complexity is accompanied by reductions in the weight, volume, power, and resupply requirements of the system. Vapor compression distillation technology is used to treat the urine, condensate, and hygiene waste streams. This contributes to the reduction in resupply, as incorporation of vapor compression distillation technology at this point in the process reduces reliance on the expendable ion exchange and adsorption media used in the current state-of-the-art water recovery system. Other proven technologies that are incorporated into the Exploration Water Recovery System include the Trace Contaminant Control System and the Volatile Removal Assembly.

ORourke, Mary Jane E.; Carter, Layne; Holder, Donald W.; Tomes, Kristin M.

2006-01-01

352

Pennsylvania Stream Water Treatment Systems  

NSDL National Science Digital Library

The video asks who will be around to keep water treatment systems going, monitor the quality of streams, and create new initiatives to keep water sources clean. A number of programs address these issues and get young people involved in environmental and conservation activities.

WPSU

2007-04-04

353

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...

354

A dented LH2 recirculation line is removed from Discovery  

NASA Technical Reports Server (NTRS)

In the Payload Changeout Room, Launch Pad 39B, United Space Alliance and NASA workers look at the replacement main propulsion system liquid hydrogen recirculation line (left) to be installed in Shuttle Discovery's aft compartment. At right is the dented line that has been removed. The 12-inch-long dent was discovered during routine aft compartment inspections Tuesday, Dec. 7. The line recirculates hydrogen from the Shuttle main engines back to the external tank during prelaunch engine conditioning. The line is being replaced and managers expect the replacement work to take about 3 days, followed by system retests and final aft compartment close-outs. Preliminary assessments reflect a launch date of Space Shuttle Discovery on mission STS-103 no earlier than Dec. 16. STS-103 is the third servicing mission for the Hubble Space Telescope.

1999-01-01

355

A dented LH2 recirculation line is removed from Discovery  

NASA Technical Reports Server (NTRS)

Workers with United Space Alliance remove Shuttle Discovery's dented main propulsion system liquid hydrogen recirculation line. From left are James Stickley, George Atkins, and Todd Biddle. The 12-inch-long dent was discovered during routine aft compartment inspections Tuesday, Dec. 7. The line recirculates hydrogen from the Shuttle main engines back to the external tank during prelaunch engine conditioning. The line is being replaced and managers expect the replacement work to take about 3 days, followed by system retests and final aft compartment close-outs. Preliminary assessments reflect a launch date of Space Shuttle Discovery on mission STS-103 no earlier than Dec. 16. STS-103 is the third servicing mission for the Hubble Space Telescope.

1999-01-01

356

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

357

Recirculating cross-correlation detector  

DOEpatents

A digital cross-correlation detector is provided in which two time-varying signals are correlated by repetitively comparing data samples stored in digital form to detect correlation between the two signals. The signals are sampled at a selected rate converted to digital form, and stored in separate locations in separate memories. When the memories are filled, the data samples from each memory are first fed word-by-word through a multiplier and summing circuit and each result is compared to the last in a peak memory circuit and if larger than the last is retained in the peak memory. Then the address line to leading signal memory is offset by one byte to affect one sample period delay of a known amount in that memory and the data in the two memories are then multiplied word-by-word once again and summed. If a new result is larger than a former sum, it is saved in the peak memory together with the time delay. The recirculating process continues with the address of the one memory being offset one additional byte each cycle until the address is shifted through the length of the memory. The correlation between the two signals is indicated by the peak signal stored in the peak memory together with the delay time at which the peak occurred. The circuit is faster and considerably less expensive than comparable accuracy correlation detectors.

Andrews, W.H. Jr.; Roberts, M.J.

1985-01-18

358

Clemson University Water System Clemson, SC  

E-print Network

of our test results that are listed in this report labeled Duke Power Water System Water Quality Table1 Clemson University Water System Clemson, SC 2001 Annual Water-Quality Report Clemson University water. We test our water using sophisticated equipment and advanced procedures. The water supplied

Duchowski, Andrew T.

359

Thermoelectric power systems and the energy-water nexus  

NASA Astrophysics Data System (ADS)

The goal of this Thesis is the development of a comprehensive methodology to evaluate the total cost of water use in the recirculating cooling loops of thermoelectric power plants. This methodology expands upon the work presented in the literature to improve estimations of the economic impact of condenser fouling. The methods developed in this Thesis are incorporated into a user friendly Combined Cost Model (CCM) interface that will allow future researchers, students and plant personnel to perform the same comparative analyses presented herein. The objective of this Thesis is the application of the CCM to determine the economic viability of treated municipal wastewater (MWW) use to replace freshwater for cooling in power plants with recirculating cooling systems. To accomplish this objective, a set of case study evaluations are included to (1) evaluate the sensitivity of the economic impact of fouling to condenser design and operation, (2) determine the cost of treated MWW use in pulverized coal power plants, and (3) compare the relative cost of degraded water use in advanced power systems such as IGCC and oxy-combustion. The results of these evaluations show that current freshwater prices do not provide an economic incentive to switch to the use of treated MWW water. However, results indicate that the breakeven differential price of freshwater, at which the total costs of using freshwater and treated MWW are equal, is only 0.52 /1000Gal. (USD 2009). In addition, the use of treated MWW for cooling is shown to be a better economic alternative to dry air cooling technology (DACT) for the conservation of freshwater resources. Cost-to-conservation estimates of treated MWW use are 1.1 /1000 Gal., in contrast to 5.6 $/1000 Gal. for DACT. This Thesis also presents a novel, hybrid coal conversion concept, the dry gasification oxy-combustion (DGOC) power cycle. This process is similar to oxy-combustion, in that it maintains a concentrated CO2 flue stream and does not utilize a complex separation step. However, coal conversion and sulfur removal are performed within a gasification unit. It is estimated to achieve CCS goals with a higher efficiency than the leading alternative strategies.

Walker, Michael Edward

360

Clemson University Water System Clemson, SC  

E-print Network

of our test results that are listed in this report labeled Duke Power Water System Water Quality Table Turbidity Units #12;2 Duke Power Water System Water Quality Table Contaminant Date Tested Unit MCL MCLG Avg1 Clemson University Water System Clemson, SC 2000 Annual Water-Quality Report Clemson University

Duchowski, Andrew T.

361

Clemson University Water System Clemson, SC  

E-print Network

of our test results that are listed in this report labeled Duke Power Water System Water Quality Table Turbidity Units #12;2 Duke Power Water System Water Quality Table Contaminant Date Tested Unit MCL MCLG Avg1 Clemson University Water System Clemson, SC 1999 Annual Water-Quality Report Clemson University

Duchowski, Andrew T.

362

Clean Water Systems in Mexico  

NSDL National Science Digital Library

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.

2010-08-31

363

Ephesus Municipal Water System Analysis  

NSDL National Science Digital Library

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.

Dora P. Crouch

1997-12-05

364

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

Microsoft Academic Search

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 m3 environmental chamber configured to simulate an office; either no filter, a

M. O. Fadeyi; C. J. Weschler; K. W. Tham

2009-01-01

365

Ultrapure Water System for Hemodialysis Therapy  

ClinicalTrials.gov

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.

2011-07-21

366

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

E-print Network

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

Paris-Sud XI, Université de

367

Calibrating Water System Models  

Microsoft Academic Search

Calibration enables a computer model to simulate field conditions accurately. Telemetry data and field measurements of the system provide base data for calibration, but computer programs that automatically extract and compare pertinent data with simulated values can aid the process. Once calibrated, the model can be used with a great degree of confidence as a predictor and as a benchmark

A. Lee Cesario; J. O. Davis

1984-01-01

368

Stab water supply system  

Microsoft Academic Search

Apparatus and method for fire suppression on offshore oil platforms including a stab receptacle on an outer surface of a platform connected to a fluid distribution system within the platform for distributing fire suppressing fluid to selected locations, a stab carrying a fluid conduit from a self-propelled service vessel, with the stab being in turn supported on a boom extending

Hammett

1983-01-01

369

A replacement LH2 recirculation line before installation in Discovery  

NASA Technical Reports Server (NTRS)

Gary Hamilton (left) and James Stickley, both with United Space Alliance, check out a spare four-inch diameter LH2 recirculation line that will be used to replace a damaged LH2 line in the orbiter Discovery. The line recirculates hydrogen from the Shuttle main engines back to the external tank during prelaunch engine conditioning. Workers noted a dent in the line during routine aft compartment inspections Tuesday, Dec. 7. The dent measures 12 inches long and about =-inch deep. Managers expect the replacement work to take about 3 days, followed by system retests and final aft compartment close-outs. Preliminary assessments reflect a launch date of Space Shuttle Discovery on mission STS-103 no earlier than Dec. 16. STS-103 is the third servicing mission for the Hubble Space Telescope.

1999-01-01

370

A replacement LH2 recirculation line before installation in Discovery  

NASA Technical Reports Server (NTRS)

A spare four-inch diameter LH2 recirculation line (shown in photo) will be used to replace a damaged LH2 line in the orbiter Discovery. The line recirculates hydrogen from the Shuttle main engines back to the external tank during prelaunch engine conditioning. Workers noted a dent in the line during routine aft compartment inspections Tuesday, Dec. 7. The dent measures 12 inches long and about =-inch deep. Managers expect the replacement work to take about 3 days, followed by system retests and final aft compartment close-outs. Preliminary assessments reflect a launch date of Space Shuttle Discovery on mission STS-103 no earlier than Dec. 16. STS-103 is the third servicing mission for the Hubble Space Telescope.

1999-01-01

371

A replacement LH2 recirculation line before installation in Discovery  

NASA Technical Reports Server (NTRS)

James Stickley (left) and Derry Dilby (right), who are with United Space Alliance, check over a spare four-inch diameter LH2 recirculation line that will be used to replace a damaged LH2 line in the orbiter Discovery. The line recirculates hydrogen from the Shuttle main engines back to the external tank during prelaunch engine conditioning. Workers noted a dent in the line during routine aft compartment inspections Tuesday, Dec. 7. The dent measures 12 inches long and about =-inch deep. Managers expect the replacement work to take about 3 days, followed by system retests and final aft compartment close-outs. Preliminary assessments reflect a launch date of Space Shuttle Discovery on mission STS-103 no earlier than Dec. 16. STS-103 is the third servicing mission for the Hubble Space Telescope.

1999-01-01

372

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

NASA Astrophysics Data System (ADS)

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.

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

2011-04-01

373

Integrated Planning for Water and Energy Systems  

E-print Network

Integrated Planning for Water and Energy Systems Integrated Planning for Water and Energy Systems University of California, Santa Barbara #12;Points to CoverPoints to Cover 1. Integrated Energy and Water Policy 2. Energy Intensity of Water 3. Water Intensity of Energy 1. Integrated Energy and Water Policy 2

Keller, Arturo A.

374

Information Sources for Small Water Systems  

E-print Network

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...

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

2007-02-19

375

Drinking Water Distribution Systems Hydraulics, Leakage, and Water Quality Issues  

E-print Network

#12; Drinking Water Distribution Systems Hydraulics, Leakage, and Water Quality Issues Life Cycle water pipes!! #12; It is demonstrated that hydraulic transients in water mains have high potential contaminants. Physical integrity of service line and hydraulic integrity at water main should be maintained

Su, Xiao

376

Reduced Volume Prototype Spacesuit Water Membrane Evaporator; A Next-Generation Evaporative Cooling System for the Advanced Extravehicular Mobility Unit Portable Life Support System  

NASA Technical Reports Server (NTRS)

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 reduced volume prototype (RVP) spacesuit water membrane evaporator (SWME). The RVP SWME is the third generation of hollow fiber SWME hardware. Like its predecessors, RVP 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. Major design improvements, including a 36% reduction in volume, reduced weight, and a more flight-like backpressure valve, facilitate the packaging of RVP SWME in the AEMU PLSS envelope. The development of these evaporative cooling systems will contribute to a more robust and comprehensive AEMU PLSS.

Makinen, Janice V.; Anchondo, Ian; Bue, Grant C.; Campbell, Colin; Colunga, Aaron

2013-01-01

377

Recirculation of Laser Power in an Atomic Fountain  

NASA Technical Reports Server (NTRS)

A new technique for laser-cooling atoms in a cesium atomic fountain frequency standard relies on recirculation of laser light through the atom-collection region of the fountain. The recirculation, accomplished by means of reflections from multiple fixed beam-splitter cubes, is such that each of two laser beams makes three passes. As described below, this recirculation scheme offers several advantages over prior designs, including simplification of the laser system, greater optical power throughput, fewer optical and electrical connections, and simplification of beam power balancing. A typical laser-cooled cesium fountain requires the use of six laser beams arranged as three orthogonal pairs of counter-propagating beams to decelerate the atoms and hold them in a three-dimensional optical trap in vacuum. Typically, these trapping/cooling beams are linearly polarized and are positioned and oriented so that (1) counter-propagating beams in each pair have opposite linear polarizations and (2) three of the six orthogonal beams have the sum of their propagation directions pointing up, while the other three have the sum of their propagation directions pointing down. In a typical prior design, two lasers are used - one to generate the three "up" beams, the other to generate the three "down" beams. For this purpose, the output of each laser is split three ways, then the resulting six beams are delivered to the vacuum system, independently of each other, via optical fibers. The present recirculating design also requires two lasers, but the beams are not split before delivery. Instead, only one "up" beam and one oppositely polarized "down" beam are delivered to the vacuum system, and each of these beams is sent through the collection region three times. The polarization of each beam on each pass through the collection region is set up to yield the same combination of polarization and propagation directions as described above. In comparison with the prior design, the present recirculating design utilizes the available laser light more efficiently, making it possible to trap more atoms at a given laser power or the same number of atoms at a lower laser power. The present design is also simpler in that it requires fewer optical fibers, fiber couplings, and collimators, and fewer photodiodes for monitoring beam powers. Additionally, the present design alleviates the difficulty of maintaining constant ratios among power levels of the beams within each "up" or "down" triplet.

Enzer, Daphna G.; Klipstein, WIlliam M.; Moore, James D.

2007-01-01

378

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...

379

Liquid hydrogen and liquid oxygen feedline passive recirculation analysis  

NASA Technical Reports Server (NTRS)

During the National Launch System design phase, a computer code (FEEDLINE) was written to analyze the feasibility of using passive recirculation propellant conditioning for the LH2 and LO2 feed systems. The FEEDLINE code was employed to provide temperature profiles to the STME design team. The team used the temperature profiles to determine if the required Space Transportation Main Engine net positive suction pressure was met. One desired outcome of the LH2 testing was to determine if modifications are required for the FEEDLINE code. The initial LN2 calibration tests indicate that the environmental heat into the system decreases with increasing heater input.

Holt, Kimberly A.; Cleary, Nicole L.; Nichols, Andrew J.; Perry, Gretchen L. E.

1993-01-01

380

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....

381

A five-year study of coastal recirculation and its effect on air pollutants over the East Mediterranean region  

NASA Astrophysics Data System (ADS)

Many studies have shown that air pollutants concentrations in coastal cities may be gravely affected by coastal recirculation. In this study an attempt is made to examine the properties of coastal recirculation over a long period (5 yrs) at multiple sites along the East Mediterranean Sea (EMS). For this purpose, a single station quantitative measure of horizontal recirculation is used based on wind field measurements over periods of 1-96 hrs. The horizontal recirculation is examined with respect to the integration time period, synoptic flow, seasonality, coastline variations, elevation, and air pollutants concentrations. The interaction between synoptic and mesoscales is shown to be a governing factor by allowing or overruling the land sea breeze winds. Favorite conditions for coastal recirculation are shown to be light or variable winds such as under a Cole or a High-Pressure system. The monthly distribution of the recirculation potential has a bimodal behavior with two peaks during the transitional seasons and October in particular. This is as a result of the annual cycle of night-time land-sea temperature difference driving the land breeze and the more frequent passage of synoptic scale flows with an easterly wind component at the EMS. Two factors leading to variations along the coastline are the urban heat island, weakening the breeze winds and reducing recirculation potential, and the concaved shape of the southern shoreline that causes a convergence and strengthening of the land breeze, thus supporting recirculation. The primary pollutants NOx and SO2 have the highest concentrations during weak daily mean wind speeds. O3 levels depict an almost opposite image of NOx, with higher values for both high and low recirculation, possibly resulting from either long range transport or coastal recirculation.

Levy, Ilan; Dayan, Uri; Mahrer, Yitzhak

2008-08-01

382

WATER DISTRIBUTION SYSTEM OPERATION: APPLICATION OF  

E-print Network

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

Mays, Larry W.

383

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...

384

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

SciTech Connect

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.

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

2011-01-01

385

Energy Conservation Through Water Usage Reduction in the Semiconductor Industry  

E-print Network

the water itself, could become a contaminant. A comparison of typical water qualities is presented in Table 1. A simplified diagram of the UPW system is presented in Figure 4. Table 1 - Typical Specifications for High Purity Water Industries !Parameter... with an inert polymer coating such as polyvinylidene fluoride (PVDF). Tanks vary in size but all are designed to store water for use in the high purity water recirculation loops. High purity water storage tanks also receive return flow from the distribution...

Mendicino, L.; McCormack, K.; Gibson, S.; Patton, B.; Lyon, D.; Covington, J.

386

Water monitor system: Phase 1 test report  

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

387

Conceptual design and thermal-hydraulic characteristics of natural circulation Boiling Water Reactors  

Microsoft Academic Search

A natural circulation boiling water reactor (BWR) with a rated capacity of 600 MW (electric) has been conceptually designed for small- and medium-sized light water reactors. The components and systems in the reactor are simplified by eliminating pumped recirculation systems and pumped emergency core cooling systems. Consequently, the volume of the reactor building is -- 50% of that for current

Y. Kataoka; H. Suzuki; M. Murase; T. Horiuchi; M. Miki

1988-01-01

388

Liquid hydrogen and liquid oxygen feedline passive recirculation analysis  

NASA Technical Reports Server (NTRS)

The primary goal of the National Launch System (NLS) program was to design an operationally efficient, highly reliable vehicle with minimal recurring launch costs. To achieve this goal, trade studies of key main propulsion subsystems were performed to specify vehicle design requirements. These requirements include the use of passive recirculation to thermally condition the liquid hydrogen (LH2) and liquid oxygen (LO2) propellant feed systems and Space Transportation Main Engine (STME) fuel pumps. Rockwell International (RI) proposed a joint independent research and development (JIRAD) program with Marshall Space Flight Center (MSFC) to study the LH2 feed system passive recirculation concept. The testing was started in July 1992 and completed in November 1992. Vertical and sloped feedline designs were used. An engine simulator was attached at the bottom of the feedline. This simulator had strip heaters that were set to equal the corresponding heat input from different engines. A computer program is currently being used to analyze the passive recirculation concept in the LH2 vertical feedline tests. Four tests, where the heater setting is the independent variable, were chosen. While the JIRAD with RI was underway, General Dynamics Space Systems (GDSS) proposed a JIRAD with MSFC to explore passive recirculation in the LO2 feed system. Liquid nitrogen (LN2) is being used instead of LO2 for safety and economic concerns. To date, three sets of calibration tests have been completed on the sloped LN2 test article. The environmental heat was calculated from the calibration tests in which the strip heaters were turned off. During the LH2 testing, the environmental heat was assumed to be constant. Therefore, the total heat was equal to the environmental heat flux plus the heater input. However, the first two sets of LN2 calibration tests have shown that the environmental heat flux varies with heater input. A Systems Improved Numerical Differencing Analyzer and Fluid Integrator (SINDA/FLUINT) model is currently being built to determine if this variation in environmental heat is due to a change in the wall temperature. During the third set of calibration tests, a faulty reference junction was found. Based on this anomaly with the reference junction, the heat flux calculations from the first two calibration sets are now considered questionable.

Holt, Kimberly Ann; Cleary, Nicole L.; Nichols, Andrew J.; Perry, Gretchen L. E.

1993-01-01

389

Stealthy deception attacks on water SCADA systems  

Microsoft Academic Search

This article investigates the vulnerabilities of Supervisory Control and Data Acquisition (SCADA) systems which monitor and control the modern day irrigation canal systems. This type of monitoring and control infrastructure is also common for many other water distribution systems. We present a linearized shallow water partial differential equation (PDE) system that can model water flow in a network of canal

Saurabh Amin; Xavier Litrico; S. Shankar Sastry; Alexandre M. Bayen

2010-01-01

390

Multi-Point Interferometric Rayleigh Scattering using Dual-Pass Light Recirculation  

NASA Technical Reports Server (NTRS)

This paper describes for the first time an interferometric Rayleigh scattering system using dual-pass light recirculation (IRS-LR) capable of simultaneously measuring at multiple points two orthogonal components of flow velocity in combustion flows using single shot laser probing. An additional optical path containing the interferometer input mirror, a quarter-wave plate, a polarization dependent beam combiner, and a high reflectivity mirror partially recirculates the light that is rejected by the interferometer. Temporally- and spatially-resolved acquisitions of Rayleigh spectra in a large-scale combustion-heated supersonic axi-symmetric jet were performed to demonstrate the technique. Recirculating of Rayleigh scattered light increases the number of photons analyzed by the system up to a factor of 1.8 compared with previous configurations. This is equivalent to performing measurements with less laser energy or performing measurements with the previous system in gas flows at higher temperatures.

Bivolaru, Daniel; Danehy, Paul M.; Cutler, Andrew D.

2008-01-01

391

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.

392

Apparatus and a method for biological treatment of waste waters  

Microsoft Academic Search

An apparatus and a method for biological treatment of waste waters achieving biological oxidation of organic matter, biological nitrification and denitrification of nitrogenous compounds and biological removal of phosphorus and clarification of the treated waste water in a single reaction tank in a single suspended growth sludge system without the use of traditional compressors, mixers, recirculation pumps, piping and valving

Besik

1983-01-01

393

Investigating phosphorus interactions with bed sediments in a fluvial environment using a recirculating flume and intact soil cores.  

PubMed

Phosphorus uptake by bed sediments in surface drains can reduce phosphorus exports from irrigated land. This paper reports on an investigation into the effects of velocity and water depth on phosphorus uptake by bed sediments, which consisted of eight sequential flow events conducted in a recirculating flume as well as a concurrent experiment using sediment cores. For the heavy clay bed sediment discussed in this paper, velocity and depth of water column had no significant effect on net phosphorus uptake and the rates of phosphorus uptake in either the cores or the recirculating flume. The most significant factor affecting phosphorus uptake was the experiment number which represented the sequential nature of experiments within the flume and increasing phosphorus saturation of the surface sediments. Of the kinetic equations used to describe phosphorus uptake (Elovich, boundary layer and diffusion) the Elovich equation provided the best representation of the results, both in terms of the adj-R2 values and the absence of systematic errors in the residuals. Results suggest that intact soil cores may be used to parameterise rate equations such as the Elovich equation for use in process-based mathematical models of phosphorus transport in fluvial systems. PMID:15276759

Barlow, Kirsten; Nash, David; Grayson, Rodger

2004-01-01

394

Adaptive predictive control of a boiling water reactor  

Microsoft Academic Search

This paper reports on an adaptive predictive control system (APCS) is applied to the design of the recirculation and feedwater control systems of a boiling water reactor. The APCS uses the dead zone method to modify the adaptive law; thus, it is stable in the presence of unmodeled dynamics and bounded disturbances. Two single-input\\/single-output control systems are used instead of

C. Lin; S. R. Chang

1991-01-01

395

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

PubMed

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

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

2012-02-01

396

Fant's Grove Water System System No, SC390112  

E-print Network

with a safe and reliable supply of high-quality drinking water. We test our water using sophisticated," is not required by the Safe Drinking Water Act (SDWA), for small, master metered water systems like the Fant's Grove Waster System. This report tells you where your water comes from, what our tests show about it

Duchowski, Andrew T.

397

Water reactive hydrogen fuel cell power system  

DOEpatents

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.

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

2014-11-25

398

Water reactive hydrogen fuel cell power system  

DOEpatents

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.

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

2014-01-21

399

Stealthy Deception Attacks on Water SCADA Systems  

E-print Network

Stealthy Deception Attacks on Water SCADA Systems Saurabh Amin1 Xavier Litrico2 Alexandre M. Bayen1 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

Hu, Fei

400

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...

401

Purification of Aquacultural Water: Conventional and New Membrane-based Techniques  

Microsoft Academic Search

Removing solids is an essential task when recirculating water an aquaculture system. Dissolved solids production directly from particulate solids as well as by fish is a function of time. These contaminants can indirectly affect the fish both biologically and physically. The flaws of conventional water treatment on seawater aquaculture systems are reviewed in this paper. Then a new technology for

Rosalam Sarbatly

2011-01-01

402

Temperature diagnostic to identify high risk areas and optimize Legionella pneumophila surveillance in hot water distribution systems.  

PubMed

Legionella pneumophila is frequently detected in hot water distribution systems and thermal control is a common measure implemented by health care facilities. A risk assessment based on water temperature profiling and temperature distribution within the network is proposed, to guide effective monitoring strategies and allow the identification of high risk areas. Temperature and heat loss at control points (water heater, recirculation, representative points-of-use) were monitored in various sections of five health care facilities hot water distribution systems and results used to develop a temperature-based risk assessment tool. Detailed investigations show that defective return valves in faucets can cause widespread temperature losses because of hot and cold water mixing. Systems in which water temperature coming out of the water heaters was kept consistently above 60 °C and maintained above 55 °C across the network were negative for Legionella by culture or qPCR. For systems not meeting these temperature criteria, risk areas for L. pneumophila were identified using temperature profiling and system's characterization; higher risk was confirmed by more frequent microbiological detection by culture and qPCR. Results confirmed that maintaining sufficiently high temperatures within hot water distribution systems suppressed L. pneumophila culturability. However, the risk remains as shown by the persistence of L. pneumophila by qPCR. PMID:25622002

Bédard, Emilie; Fey, Stéphanie; Charron, Dominique; Lalancette, Cindy; Cantin, Philippe; Dolcé, Patrick; Laferrière, Céline; Déziel, Eric; Prévost, Michèle

2015-03-15

403

High Power Picosecond Laser Pulse Recirculation  

SciTech Connect

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.

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

404

Electroporation System for Sterilizing Water  

NASA Technical Reports Server (NTRS)

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.

Schlager, Kenneth J.

2005-01-01

405

Bathymetry-Density Interaction as a Driver for Seawater Recirculation in Submarine Groundwater Discharge  

NASA Astrophysics Data System (ADS)

A new mechanism for shallow saltwater recirculation as a component of submarine groundwater discharge (SGD) in coastal areas is proposed and evaluated. The proposed process occurs as a result of the interaction between bedform topography and buoyancy forces without requiring transient forcing (e.g., tides or waves) or currents over the bedform. Under hydrostatic seawater, the equivalent freshwater head is greatest on the seabed surface at the troughs of the bedform and lowest at the crest. In this mechanism, the inverted salinity (and density) profile in the presence of both a bedform on the seafloor and upward flow of fresher groundwater from depth induces a downward flow of saline porewater under the troughs and upward flow under the adjacent crest of the bedform. The magnitude and occurrence of the mechanism were evaluated and tested using the SEAWAT model. The results indicate that this mechanism could drive seawater recirculation and contribute 20 to 30 percent of local SGD under a range of realistic conditions. Bedform shape, hydraulic conductivity, hydraulic head and salinity at depth in the porous media, aquifer thickness, effective porosity, and hydrodynamic dispersion are among the factors that control the occurrence and magnitude of the recirculation of seawater, though the upward flux of fresher water is a dominant control. The hydraulic head at depth generally decreases with distance offshore as the head dissipates with the upward flow and discharge of the deeper fresher groundwater. Thus, one might anticipate the occurrence of a banded pattern—approximately parallel to the shoreline—of saltwater recirculation due to topographic-density interaction. Close to shore, the underlying head might be so large as to preclude saltwater recirculation, and far offshore fresher groundwater at depth may be absent or the head might be so small as to preclude upwards flow of deeper groundwater, thereby also eliminating the saltwater recirculation due to topographic-density interaction.

Konikow, L. F.; Akhavan, M.; Sawyer, A. H.; Michael, H. A.; Langevin, C. D.

2012-12-01

406

Generation of Flat Optical Frequency Comb based on Mach-Zehnder Modulator and Recirculating Frequency Shifter Loop  

NASA Astrophysics Data System (ADS)

We propose a novel scheme to generate optical frequency comb by using Mach-Zehnder modulator and recirculating frequency shifter loop based on IQ modulator driven by radio frequency clock signals. A system of 4 flat and stable comb lines generation based on Mach-Zehnder modulator is set as the seed light source of the recirculating loop. Through theorical analysis and simulation it is shown that the proposed theoretical model is proved in good agreement with simulation results.

Wu, Shibao; Li, Yulong; Fei, Yue; Hu, Faze

2014-06-01

407

Using elastic joint to reduce the impact between ball and re-circulating mechanism in ball screw  

Microsoft Academic Search

A ball screw driven mechanism is a major component in high-speed\\/high-precision transmitting systems. In such a mechanism, the re-circulating mechanism has been designed to provide the path for steel balls rolling in screw grooves. As the driven shaft in the mechanism operates at high rotating speed, forces caused by the impact activity between the steel ball and re-circulating mechanism may

Zuoying Zhang

2008-01-01

408

A novel design method to reduce the impact between ball and re-circulating mechanism in ball screws  

Microsoft Academic Search

In high-speed\\/high-precision ball screw transmitting systems, the re-circulating mechanism of ball screws is used for providing the path for steel balls rolling in screw grooves generally. Because the rotating speed of the driven shaft in the mechanism has become higher and higher, forces caused by the impact activity between the steel ball and re-circulating mechanism has resulted in a series

Xiangrong Xu; Xianchun Song; Zuoying Zhang; Hongkui Jiang

2009-01-01

409

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...

410

ASSESSING POWER PLANT COOLING WATER INTAKE SYSTEM  

E-print Network

ASSESSING POWER PLANT COOLING WATER INTAKE SYSTEM ENTRAINMENT IMPACTS Prepared For: California power plants and other industrial facilities that withdraw cooling water from surface water bodies regulated under Section 316(b), steam electric power plants represent the largest cooling water volumes

411

ENHANCING WATER SYSTEM SECURITY AND SUSTAINABILITY BY INCORPORATING CENTRALIZED AND DECENTRALIZED WATER RECLAMATION AND REUSE INTO URBAN WATER MANAGEMENT SYSTEMS  

Microsoft Academic Search

The concept of integrated urban water management, incorporating centralized and decentralized water supply and wastewater management along with water reclamation and reuse, distributed water treatment, and rainwater harvesting is introduced. Such systems are referred to as hybrid systems, and they provide the advantages and disadvantages of both parent systems. Hybrid systems use individual technologies (some identified in this paper) assembled

Glen T. Daigger; George V. Crawford

2007-01-01

412

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

NASA Astrophysics Data System (ADS)

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.

Kempel, F. D.

1985-07-01

413

Sustainable Water Use System of Artesian Water in Alluvial Fan  

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

414

Water System Resiliency: Lessons from Boston's 2010 Water Emergency  

NASA Astrophysics Data System (ADS)

On May 1, 2010, a ten foot diameter water pipe, the sole pipe supplying potable water to 2.2 million residents of Greater Boston, burst. Categorized as a "catastrophic" leak by the Massachusetts Water Resources Authority, Governor Deval Patrick declared a State of Emergency, mobilizing local, state and federal disaster responses. By May 4, 2010, a boil-water order was lifted after the leak was fixed. This event has provided many lessons about the resiliency of municipal water system infrastructure, the level of human understanding of reliability and vulnerability of resource distribution systems, and the human capacity to adapt in short and longer terms to disturbances in resource distribution systems, and to learn. This talk will use a narrative of the events during May 2010 in Boston to explore the broader question of the nature of resilient resource distribution networks, and describe a heuristic, semi-quantitative model for resilient urban resource distribution networks, including water.

Phillips, N.; Boston Urban Metabolism Ultra-Ex Team

2010-12-01

415

Wireless Automatic Water-meter Reading System  

Microsoft Academic Search

Wireless automatic meter reading (AMR) system based on a fixed radio network brings many advantages when compared to other meter reading techniques. After an introduction to the state of the art of AMR systems in general, and particularly of water meter reading system, a wireless automatic water-meter reading system founded on ZigBee technology is presented. Set forth in the text

Vedran Bilas

416

Combined air and water pollution control system  

NASA Technical Reports Server (NTRS)

A bioaquatic air pollution control system for controlling both water and atmospheric pollution is disclosed. The pollution control system includes an exhaust for directing polluted gases out of a furnace and a fluid circulating system which circulates fluid, such as waste water, from a source, past the furnace where the fluid flow entrains the pollutants from the furnace. The combined fluid and pollutants are then directed through a rock/plant/microbial filtering system. A suction pump pumps the treated waste water from the filter system past the exhaust to again entrain more pollutants from the furnace where they are combined with the fluid (waste water) and directed to the filter system.

Wolverton, Billy C. (inventor); Jarrell, Lamont (inventor)

1990-01-01

417

MODELLING INTERMITTENT WATER SUPPLY SYSTEMS WITH EPANET  

Microsoft Academic Search

Modeling rural networks and intermittent water supply systems is a challenging task because these systems are not fully pressurized pipeline networks but networks with very low pressures, with restricted water supply hours per day, and with thousands of ferrule points and roof tank connections. The alternate emptying and refilling of water pipelines makes it problematic to apply standard EPANET based

DHI India

418

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, ...

419

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

NASA Astrophysics Data System (ADS)

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.

Fadeyi, M. O.; Weschler, C. J.; Tham, K. W.

420

Impact of nitrate-enhanced leachate recirculation on gaseous releases from a landfill bioreactor cell.  

PubMed

This study evaluates the impact of nitrate injection on a full scale landfill bioreactor through the monitoring of gaseous releases and particularly N(2)O emissions. During several weeks, we monitored gas concentrations in the landfill gas collection system as well as surface gas releases with a series of seven static chambers. These devices were directly connected to a gas chromatograph coupled to a flame ionisation detector and an electron capture detector (GC-FID/ECD) placed directly on the field. Measurements were performed before, during and after recirculation of raw leachate and nitrate-enhanced leachate. Raw leachate recirculation did not have a significant effect on the biogas concentrations (CO(2), CH(4) and N(2)O) in the gas extraction network. However, nitrate-enhanced leachate recirculation induced a marked increase of the N(2)O concentrations in the gas collected from the recirculation trench (100-fold increase from 0.2 ppm to 23 ppm). In the common gas collection system however, this N(2)O increase was no more detectable because of dilution by gas coming from other cells or ambient air intrusion. Surface releases through the temporary cover were characterized by a large spatial and temporal variability. One automated chamber gave limited standard errors over each experimental period for N(2)O releases: 8.1 +/- 0.16 mg m(-2) d(-1) (n = 384), 4.2 +/- 0.14 mg m(-2) d(-1) (n = 132) and 1.9 +/- 0.10 mg m(-2) d(-1) (n = 49), during, after raw leachate and nitrate-enhanced leachate recirculation, respectively. No clear correlation between N(2)O gaseous surface releases and recirculation events were evidenced. Estimated N(2)O fluxes remained in the lower range of what is reported in the literature for landfill covers, even after nitrate injection. PMID:19297142

Tallec, G; Bureau, C; Peu, P; Benoist, J C; Lemunier, M; Budka, A; Presse, D; Bouchez, T

2009-07-01

421

Optimization of Chilled Water Systems  

E-print Network

rise in chilled water supply temperature results in an increase of 1 to 1.5 percent in coefficient of performance (COF). Even for the same temperature difference (10 of between supply and return water), the power consumption is considerably less... to reset the condenser water temperature. Reset Condenser Water Temperature Calculations :. Energy Savings Average Load (tons) x kW/ton x Operating Hours x Percent Power Reduction Where: Percent Power Reduction (Design Condenser Water Temperature...

Gidwani, B. N.

422

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...

423

Production of cobia in recirculating aquaculture systems  

Technology Transfer Automated Retrieval System (TEKTRAN)

Interest in cobia Rachycentron canadum aquaculture in the US has increased greatly in the last decade due to their excellent consumer appeal, extremely rapid growth rates, and the observed success of rearing this species in Taiwan and other southeastern Asian countries. Because most cobia are grown...

424

Rate Setting for Small Water Systems  

E-print Network

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...

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

2007-03-28

425

Mining Gold from your Cooling Water System  

E-print Network

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...

Mendez, T.

426

Design data brochure: Solar hot water system  

NASA Technical Reports Server (NTRS)

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.

1978-01-01

427

Corrosion control in water injection systems  

SciTech Connect

Corrosion control in water injection systems encompasses a wide range of technologies, including chemicals (corrosion inhibitors, biocides, and oxygen scavengers); corrosion-resistant materials (metallic and nonmetallic); internal coatings and linings; mechanical removal of dissolved oxygen; velocity control; and prevention of oxygen entry and galvanic couples. This article reviews the way that these technologies are used in modern water-injection systems (both seawater and produced water) to provide an acceptable service life and high-quality injection water.

Patton, C.C. (C.C. Patton and Associates Inc., Dallas, TX (United States))

1993-08-01

428

A Synergistic Combination of Advanced Separation and Chemical Scale Inhibitor Technologies for Efficient Use of Imparied Water As Cooling Water in Coal-based Power Plants  

Microsoft Academic Search

Nalco Company is partnering with Argonne National Laboratory (ANL) in this project to jointly develop advanced scale control technologies that will provide cost-effective solutions for coal-based power plants to operate recirculating cooling water systems at high cycles using impaired waters. The overall approach is to use combinations of novel membrane separations and scale inhibitor technologies that will work synergistically, with

Jasbir Gill

2010-01-01

429

Cost analysis of water recovery systems  

NASA Technical Reports Server (NTRS)

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.

Yakut, M. M.

1972-01-01

430

Original Research Article Influence of anodic gas recirculation on solid oxide fuel cells in a micro  

E-print Network

-oxide fuel cells systems are ideally suited to operate on hydrocarbons, directly converting fuelOriginal Research Article Influence of anodic gas recirculation on solid oxide fuel cells January 2014 Revised 23 July 2014 Accepted 5 August 2014 Keywords: SOFC Steam reforming Fuel processing

Nielsen, Mads Pagh

431

PILOT SCALE WATER REUSE SYSTEM  

EPA Science Inventory

The efficiency of the treatment technologies is expected to vary with the source water quality. By testing the technologies with various source waters, the research will quantify the limits of the technology: testing the flow rate variations with influent water quality, evalu...

432

Exhaust gas recirculation in a homogeneous charge compression ignition engine  

DOEpatents

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.

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

433

SAFE DRINKING WATER INFORMATION SYSTEM (STATE)  

EPA Science Inventory

Resource Purpose: The Safe Drinking Water Information System (STATE) (SDWIS/STATE) is an information system OGWDW is developing for states and EPA regions to manage their water industry. SDWIS/STATE is not an information system for which EPA HQ is using to store or retrie...

434

DISTRIBUTION SYSTEM RESEARCH (WATER SUPPLY AND WATER RESOURCES DIVISION)  

EPA Science Inventory

Two water distribution system simulators(DSSs)are now in operation at the USEPA Test and Evaluation (T&E) Facility in Cincinnati, OH. EPA's T&E Facility is a multifaceted research resource in which a wide variety of water treatment and other environmental protection technologies ...

435

Hot water heating system having minimum hot water use based on minimum water temperatures and time of heating  

Microsoft Academic Search

This patent describes a water heater control system for constantly controlling the heating and use of hot water from a water heater unit of the type having water heater means with a water heater control means therefor converting between on for heating water and off free of heating water. The control system comprises a water inlet means for feeding water

T. R. Vandermeyden; O. R. Dufau; F. J. Blau

1986-01-01

436

Reflective Amplified Recirculating Delay Line Bandpass Filter  

NASA Astrophysics Data System (ADS)

A new microwave photonic filter structure that can achieve a high Q factor, high stopband rejection, and high skirt selectivity bandpass filter response simultaneously is presented. It is based on reflecting the signal back into a single amplified optical recirculating delay line and comprises coherent summation of the multiple signals that constitute each tap and incoherent summation of the successive taps. This introduces a new class of filter operation and effectively enables the realization of a higher order bandpass filter characteristic in a very simple structure. Experimental results are presented that demonstrate a multiple-tap high-Q bandpass filter response that also displays high stopband rejection level and high skirt selectivity.

Chan, Erwin H. W.; Minasian, Robert A.

2007-06-01

437

Water recycle method for washing alkali-refined soybean oil  

Microsoft Academic Search

Vegetable oil refineries are faced today with cutting down on pollution caused by their waste water. A method was developed\\u000a for washing alkali-refined soybean oil with treated, recirculated wash water. In this method, wash water passes through a\\u000a cation exchange resin that removes Na, and the slightly acid water goes back into the system for continuous reuse. The disposal\\u000a problem

R. A. Eisenhauer; R. E. Beal; E. L. Griffin

1970-01-01

438

Space shuttle galley water system test program  

NASA Technical Reports Server (NTRS)

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.

1975-01-01

439

Water on Small Solar System Bodies  

Microsoft Academic Search

\\u000a When examining the outer parts of the solar system water becomes more and more abundant. The water reservoir on the Erath\\u000a and other terrestrial planets might have been supplied by the impact of these objects in the heavy bombardment phase of the\\u000a early solar system evolution. Water on small solar system bodies such as asteroids, comets, objects in the Kuiper

Arnold Hanslmeier

440

Comparison of experimental and simulated thermal ratings of drain-back solar water heaters  

Microsoft Academic Search

Short-term experimental tests of drain-back solar water heaters are compared to ratings obtained using TRNSYS to determine if computer simulations can effectively replace laboratory thermal ratings of solar domestic hot water heating systems. The effectiveness of TRNSYS in predicting changes in rating due to limited changes in collector area, collector flow rate, recirculation flow rate, storage tank volume, and storage

J. H. Davidson; W. T. Carlson; W. S. Duff; P. J. Schaefer; W. A. Beckman; S. A. Klein

1993-01-01

441

Neutron Diffraction from Clay-Water Systems  

Microsoft Academic Search

The use of neutron diffraction to determine some of the structural properties of montmorillonite-water systems at low water concentrations is described. The samples were prepared by compression or suction to give clay samples with between one and three molecular layers of water between the plates. About 10% of the platelets in the clay are randomly oriented. The remainder are partially

D. J. Cebula; R. K. THOMAS; S. MIDDLETON; R. H. OTTEWILL

1979-01-01

442

Local system responses to water shortage  

Microsoft Academic Search

Water shortages have become increasingly serious natural resource problems in recent years. In most cases local water systems are responsible for programs to reduce individual water use. The effectiveness of these organizations is related to their ability to obtain information and assistance from other organizations at the local, state, and federal levels. This paper examines the experiences of 28 local

Thomas J. Hoban IV

1990-01-01

443

The effect of sludge recirculation rate on a UASB-digester treating domestic sewage at 15 °C.  

PubMed

The anaerobic treatment of low strength domestic sewage at low temperature is an attractive and important topic at present. The upflow anaerobic sludge bed (UASB)-digester system is one of the anaerobic systems to challenge low temperature and concentrations. The effect of sludge recirculation rate on a UASB-digester system treating domestic sewage at 15 °C was studied in this research. A sludge recirculation rate of 0.9, 2.6 and 12.5% of the influent flow rate was investigated. The results showed that the total chemical oxygen demand (COD) removal efficiency rose with increasing sludge recirculation rate. A sludge recirculation rate of 0.9% of the influent flow rate led to organic solids accumulation in the UASB reactor. After the sludge recirculation rate increased from 0.9 to 2.6%, the stability of the UASB sludge was substantially improved from 0.37 to 0.15 g CH?-COD/g COD, and the bio-gas production in the digester went up from 2.9 to 7.4 L/d. The stability of the UASB sludge and bio-gas production in the digester were not significantly further improved by increasing sludge recirculation rate to 12.5% of the influent flow rate, but the biogas production in the UASB increased from 0.37 to 1.2 L/d. It is recommended to apply a maximum sludge recirculation rate of 2-2.5% of the influent flow rate in a UASB-digester system, as this still allows energy self-sufficiency of the system. PMID:23109575

Zhang, Lei; Hendrickx, Tim L G; Kampman, Christel; Zeeman, Grietje; Temmink, Hardy; Li, Weiguang; Buisman, Cees J N

2012-01-01

444

High speed exhaust gas recirculation valve  

DOEpatents

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.

Fensom, Rod (Peterborough, GB); Kidder, David J. (Peterborough, GB)

2005-01-18

445

Liquid Assets: A Water System  

NSDL National Science Digital Library

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.

WPSU

2008-11-20

446

Cost analysis of water recovery systems  

NASA Technical Reports Server (NTRS)

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.

Yakut, M. M.

1973-01-01

447

A novel thermal water pump for circulating water in a solar water heating system  

Microsoft Academic Search

This research purpose was to perform a parametric study of a novel thermal water pump well fitted in a simulated solar water heating system (SWHS). The SWHS was composed of a heating tank (HT), a hot water storage tank (ST) and an overhead tank (OT). The HT together with a specially designed valve act as a novel thermal water pump

Natthaphon Roonprasang; Pichai Namprakai; Naris Pratinthong

2009-01-01

448

System for removal of arsenic from water  

DOEpatents

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.

Moore, Robert C.; Anderson, D. Richard

2004-11-23

449

NASA's Plum Brook Station Water Systems  

NASA Technical Reports Server (NTRS)

Plum Brook Station's water systems were built in the 1940s to support a World War II ordnance production complex. Because the systems had not been analyzed for current NASA usage, it was unknown if they could meet current requirements and codes or if they were efficient for current use. NASA wanted to determine what improvements would be needed or advisable to support its research projects, so it contracted a hydraulic analysis of the raw and domestic water systems. Burgess and Niple determined current water demands and water flow, developed and calibrated models of the two water systems, and evaluated efficiency improvements and cost-cutting options. They recommended replacing some water mains, installing a new service connection, and removing some high-maintenance items (an underground reservoir, some booster pumps, and a tower).

Puzak, Robert M.; Kimpton, Arthur

2006-01-01

450

Prototype solar domestic hot water systems  

NASA Technical Reports Server (NTRS)

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.

1978-01-01

451

Vortex dynamics and scalar transport in the wake of a bluff body driven through a steady recirculating flow  

NASA Astrophysics Data System (ADS)

The air ventilation system in wide-body aircraft cabins provides passengers with a healthy breathing environment. In recent years, the increase in global air traffic has amplified contamination risks by airborne flu-like diseases and terrorist threats involving the onboard release of noxious materials. In particular, passengers moving through a ventilated cabin may transport infectious pathogens in their wake. This paper presents an experimental investigation of the wake produced by a bluff body driven through a steady recirculating flow. Data were obtained in a water facility using particle image velocimetry and planar laser induced fluorescence. Ventilation attenuated the downward convection of counter-rotating vortices produced near the free-end corners of the body and decoupled the downwash mechanism from forward entrainment, creating stagnant contaminant regions.

Poussou, Stephane B.; Plesniak, Michael W.

2012-09-01

452

Basics of Solar Heating & Hot Water Systems.  

ERIC Educational Resources Information Center

In presenting the basics of solar heating and hot water systems, this publication is organized from the general to the specific. It begins by presenting functional and operational descriptions of solar heating and domestic hot water systems, outlining the basic concepts and terminology. This is followed by a description of solar energy utilization…

American Inst. of Architects, Washington, DC.

453

Vulnerability Assessment of Regional Water Distribution Systems  

Microsoft Academic Search

A vulnerability assessment model for regional water distribution system (VAMRWDS) is presented. The model takes into account the impact of residual chlorine and water age, as well as the uncertainty and probabilistic characteristic of the distribution systems. Monte-Carlo stochastic simulation is adopted in the model to randomly generate bulk and wall reaction coefficients. Employing the EPANET toolkit as the hydraulic

Baoyu Zhuang; Xinhua Zhao; Yuan Zhao

2009-01-01

454

Simulation in operation of water supply systems  

Microsoft Academic Search

Simulation techniques in the operation of water supply systems have the following advantages: (a) enables the engineer to evaluate the efficiency of his design options and so attain maximum efficiency; (b) enables the operators to monitor the hydraulic feasibility of heuristic or optimized operation schedules; and (c) enables the forecasting of water flows through the hydraulic system. In Mekorot two

Y. Kadar; E. Damelin

455

Solar-powered hot-water system  

NASA Technical Reports Server (NTRS)

Hot-water system requires no external power except solar energy. System is completely self-controlling. It includes solar-powered pump, solar-thermally and hydrothermally operated valves, and storage tank filled with open-celled foam, to maintain thermal stratification in stored water.

Collins, E. R.

1979-01-01

456

Energy savings from air recirculation in peanut curing  

SciTech Connect

A thin-layer peanut drying simulation model was adapted to incorporate air recirculation. Laboratory crop dryers were designed and constructed to conduct experiments to verify the model. Five batches of peanuts were dried using different recirculation strategies. The model successfully predicted the results.

Cook, D.F.; Cundiff, J.S.; Vaughan, D.H.

1982-12-01

457

Exhaust gas recirculation valve with adjustable pressure transducer  

Microsoft Academic Search

An exhaust gas recirculation valve assembly is provided for controlling the recirculation of exhaust gases in an internal combustion engine. The assembly includes a fixed body portion having an exhaust inlet and an exhaust outlet port and an adjustable exhaust back-pressure transducer portion movable within the valve. A diaphragm is attached to the body and to the upper and lower

D. P. Dunham; W. A. Treadwell

1980-01-01

458

Important influent-water quality parameters at freshwater production sites in two salmon producing countries  

Microsoft Academic Search

Further growth in Atlantic salmon (Salmo salar) aquaculture production is expected, and as a response to limited freshwater resources, recirculating aquaculture systems (RAS) are increasingly applied in smolt production. Knowledge of the general composition and quality of inlet-water is important for designing water-treatment to obtain optimal water quality in both flow-through and RAS systems. Based on water quality surveys in

T. Kristensen; Å. Åtland; T. Rosten; H. A. Urke; B. O. Rosseland

2009-01-01

459

Public Health Issues Associated with Small Drinking Water Systems  

E-print Network

Public Health Issues Associated with Small Drinking Water Systems Not Regulated by the Safe Drinking Water Act From: Nonfederally Regulated Drinking Water Systems: State and Local Public Health ...........................................................................................5 Priority Environmental Public Health Challenges for Small Drinking Water Systems

460

21 CFR 1250.42 - Water systems; constant temperature bottles.  

Code of Federal Regulations, 2013 CFR

... Water systems; constant temperature bottles. 1250.42 Section 1250.42 Food... Water systems; constant temperature bottles. (a) The water system, whether...the water. (e) Constant temperature bottles and other containers used for...

2013-04-01

461

21 CFR 1250.42 - Water systems; constant temperature bottles.  

Code of Federal Regulations, 2012 CFR

... Water systems; constant temperature bottles. 1250.42 Section 1250.42 Food... Water systems; constant temperature bottles. (a) The water system, whether...the water. (e) Constant temperature bottles and other containers used for...

2012-04-01

462

21 CFR 1250.42 - Water systems; constant temperature bottles.  

Code of Federal Regulations, 2014 CFR

... Water systems; constant temperature bottles. 1250.42 Section 1250.42 Food... Water systems; constant temperature bottles. (a) The water system, whether...the water. (e) Constant temperature bottles and other containers used for...

2014-04-01

463

21 CFR 1250.42 - Water systems; constant temperature bottles.  

Code of Federal Regulations, 2011 CFR

... Water systems; constant temperature bottles. 1250.42 Section 1250.42 Food... Water systems; constant temperature bottles. (a) The water system, whether...the water. (e) Constant temperature bottles and other containers used for...

2011-04-01

464

GPR-Based Water Leak Models in Water Distribution Systems  

PubMed Central

This paper addresses the problem of leakage in water distribution systems through the use of ground penetrating radar (GPR) as a nondestructive method. Laboratory tests are performed to extract features of water leakage from the obtained GPR images. Moreover, a test in a real-world urban system under real conditions is performed. Feature extraction is performed by interpreting GPR images with the support of a pre-processing methodology based on an appropriate combination of statistical methods and multi-agent systems. The results of these tests are presented, interpreted, analyzed and discussed in this paper.

Ayala-Cabrera, David; Herrera, Manuel; Izquierdo, Joaquín; Ocaña-Levario, Silvia J.; Pérez-García, Rafael

2013-01-01

465

Particle capture by turbulent recirculation zones measured using long-time Lagrangian particle tracking  

Microsoft Academic Search

We have measured the trajectories of particles into, and around, the recirculation zone formed in water flowing through a\\u000a sudden pipe expansion with radius ratio 1:3.7, at Reynolds numbers between 5,960 and 41,700 over a range of particle Stokes\\u000a number (here defined as $$ St = {\\\\frac{{T_{\\\\text{f}} }}{{\\\\tau_{\\\\text{p}} }}} $$, where T\\u000a f is an appropriate mean or turbulent timescale

Y. W. SiuA; A. M. K. P. Taylor

2011-01-01

466

'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...

467

Submersible purification system for radioactive water  

DOEpatents

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.

Abbott, Michael L. (Fort Collins, CO); Lewis, Donald R. (Pocatello, ID)

1989-01-01

468

Water turbine system and method of operation  

DOEpatents

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.

Costin, Daniel P. (Montpelier, VT)

2011-05-10

469

Water turbine system and method of operation  

DOEpatents

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.

Costin, Daniel P.

2010-06-15

470

Performance of two-stage vegetable waste anaerobic digestion depending on varying recirculation rates.  

PubMed

Vegetable waste, which characterized by high moisture content, was evaluated as a substrate for biogas production. The effects of recirculation rate (RR) on the performance of two-stage anaerobic digestion were investigated. The system was operated at an organic loading rate of 1.7 g VS/L/d with varying RRs (0, 0.6, 1, and 1.4). Results demonstrated that volumetric biogas production rates in acidogenic reactor increased from approximately 0.2 7 L/L/d to 0.97 L/L/d, when pH is increased from approximately 5.1 to 6.7. These indicate that recirculation of alkaline effluent from the methanogenic reactor helps create a favorable condition for biogas production in the acidogenic reactor. The decrease in chemical oxygen demand (COD) concentrations from approximately 21,000 mg/L to 6800 mg/L was also observed in the acidogenic reactor. This condition may be attributed to dilution under recirculation. The dynamics between hydrolysis and methanogenesis under recirculation indicated that mass transfer capacity between two-stage reactors improved. PMID:24759642

Zuo, Zhuang; Wu, Shubiao; Zhang, Wanqin; Dong, Renjie

2014-06-01

471

Standards and guides of water treatment and water-distribution systems. Manual for 1974-86  

Microsoft Academic Search

The following five important documents are compiled for design of municipal water treatment facilities and water distribution systems: (1) Ten States Recommended Standards for Water Works; (2) A Public Water Supply Guide--Designing Community Water Systems; (3) Water Supply Guide Lines for Public Water Systems; (4) American National Standard for the Thickness Design of Ductile-Iron Pipe; and (5) Designing for Cast

L. K. Wang; M. H. S. Wang

1987-01-01

472

Single-station integral measures of atmospheric stagnation, recirculation and ventilation  

NASA Astrophysics Data System (ADS)

Mathematical definitions of integral quantities used to characterize the stagnation, recirculation and ventilation potential of various airsheds are proposed. These integral quantities can be calculated from wind data collected at fixed time intervals and at fixed heights in the atmosphere, and could be calculated, for example, from data from ground-based remote wind profilers. These integral quantities, since they are calculated from data at single stations, provide useful characterizations of the flow at individual measurement points, but are true measures of the transport of a plume only under idealized homogenous wind conditions. The utility of these single-station measures for characterizing the air pollution transport potential of an airshed is illustrated using three months of hourly surface and radar profiler measurements of horizontal wind speed and direction collected at three locations in the Colorado Plateaus Basin region of Arizona during the winter of 1990. A surface station at Bullfrog Basin, located on a sheltered basin floor and exposed to diurnal wind systems, experienced stagnations 62% of the time, recirculations 34% of the time, and ventilations 8% of the time. A surface station at Desert View, located on the south rim of the Grand Canyon and exposed to synoptic-scale wind systems, experienced stagnations 8% of the time, recirculations 4% of the time, and ventilations 35% of the time. A radar profiler station at Page, Arizona, experienced stagnations about 20% of the time and recirculations about 25% of the time during the winter at heights below ˜ 400 m a.g.l.; above this height, to levels near 1100 m a.g.l. (the approximate height of surrounding plateaus), the frequency of stagnations and recirculations dropped rapidly, and the frequency of ventilations ranged from 40 to 70%.

Allwine, K. Jerry; Whiteman, C. David

473

Screening and evaluation of microbiologically influenced corrosion (MIC) in seawater and effluent water injection systems in Kuwait  

SciTech Connect

Injection water sources in Kuwait range from brackish water (TDS=4000 mg/l) through seawater (TDS = 30,000 mg/l) to high saline brines (TDS = 200,000 mg/l). Some of these water sources are highly sulfide sour and may require treatment to prevent scaling, corrosion or iron sulfide precipitation. Another particular problem in water injection systems is the uncontrolled growth of sulfate-reducing bacteria (SRB) which leads to increased corrosion of the process plant. Therefore, evaluation schemes were undertaken to study the relative risks of MIC in a range of Kuwait`s water sources, using a combination of field sampling and laboratory biofouling trials. Recirculating biofouling loops were set up with the appropriate site water, and inoculated with the bacteria from the system so that an active biofilm was set up on small studs. These biofouled studs were treated with proprietary biocide inhibitors under various dose rates in order to select the most appropriate control regime for particular water chemistries and process options.

Al-Hashem, A.; Salman, M.; Carew, J. [Kuwait Inst. for Scientific Research, Safat (Kuwait). Petroleum, Petrochemicals and Materials Div.

1999-11-01

474

Biofilm formation and multiplication of Legionella in a model warm water system with pipes of copper, stainless steel and cross-linked polyethylene.  

PubMed

Legionella pneumophila was grown in a model warm water system with pipes of copper (Cu), stainless steel (SS) and cross-linked polyethylene (PEX) during recirculation of tap water at 25--35 degrees C. Subsequently, domestic use of warm (37 degrees C) water was simulated using tap water with a low AOC concentration (<10 microg C/L). Two times each week the temperature of the water in the electric heaters (not in the pipes) was elevated to 70 degrees C for 30 min. ATP concentrations in the water sampled from the pipes over a 2-year period were significantly different for the pipe materials, with median values of 2.1 ng/l (Cu), 2.5 ng/l (SS) and 4.5 ng/l (PEX), respectively. Median values of the biofilm concentration were similar on Cu and SS (about 630 pg ATP/cm(2)) and 1870 pg ATP/cm(2) on PEX. Legionella multiplied in these biofilms and median values of Legionella concentrations in water were 1500 CFU/l (Cu) and about 4300 CFU/l for SS and PEX. Legionella to ATP ratios in water had median values of about 0.8 CFU/pg. Hot water flushing (70 degrees C) of the pipes on day 552, followed by 2 weeks of recirculation at 37 degrees C, caused strongly increased concentrations of ATP (up to 300 ng/l) and Legionella (>10(7)CFU/l), with about 100 CFU/pg ATP. Concentrations declined to original levels within 1 week of domestic water use, etc. Legionella concentrations in water and biofilms were at the same levels for all materials after 2 years. Hence, copper temporarily limited the growth of Legionella under the applied conditions and a rapid biomass development strongly increased the Legionella to ATP ratio. PMID:16019051

van der Kooij, Dick; Veenendaal, Harm R; Scheffer, Will J H

2005-08-01

475

Recirculating Linac Accelerators For Future Muon Facilities  

SciTech Connect

Neutrino Factories (NF) and Muon Colliders (MC) require rapid acceleration of shortlived 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. We discuss the optics and technical requirements for RLA designs, using RF cavities capable of simultaneous acceleration of both m+ and m- species. The design will include the optics for the multi-pass linac and droplet-shaped return arcs.

Yves Roblin, Alex Bogacz, Vasiliy Morozov, Kevin Beard

2012-04-01

476

Recirculation bubbler for glass melter apparatus  

DOEpatents

A gas bubbler device provides enhanced recirculation of molten glass within a glass melter apparatus. The bubbler device includes a tube member disposed within a pool of molten glass contained in the melter. The tube member includes a lower opening through which the molten glass enters and upper slots disposed close to (above or below) the upper surface of the pool of molten glass and from which the glass exits. A gas (air) line is disposed within the tube member and extends longitudinally thereof. A gas bubble distribution device, which is located adjacent to the lower end of the tube member and is connected to the lower end of the gas line, releases gas through openings therein so as to produce gas bubbles of a desired size in the molten glass and in a distributed pattern across the tube member.

Guerrero, Hector (Evans, GA); Bickford, Dennis (Folly Beach, SC)

2007-06-05

477

Nutrient Management in Recirculating Hydroponic Culture  

NASA Technical Reports Server (NTRS)

There is an increasing need to recirculate and reuse nutrient solutions in order to reduce environmental and economic costs. However, one of the weakest points in hydroponics is the lack of information on managing the nutrient solution. Many growers and research scientists dump out nutrient solutions and refill at weekly intervals. Other authors have recommended measuring the concentrations of individual nutrients in solution as a key to nutrient control and maintenance. Dumping and replacing solution is unnecessary. Monitoring ions in solution is not always necessary; in fact the rapid depletion of some nutrients often causes people to add toxic amounts of nutrients to the solution. Monitoring ions in solution is interesting, but it is not the key to effective maintenance.

Bugbee, Bruce

2004-01-01