Dynamic effects of NO2--N accumulation were discussed owing to temperature.In different temperature,a series of vmax and Ks were found considering the relation between the temperature and rate of ammonia nitrogen tran...Dynamic effects of NO2--N accumulation were discussed owing to temperature.In different temperature,a series of vmax and Ks were found considering the relation between the temperature and rate of ammonia nitrogen transforming into NO2--N.The kinetics models,which reflected the conditions of ammonia nitrogen transforming into NO2--N in the treatment process of the coking wastewater,were built up.The characteristic coefficient temperature was determined according to Arrhenius.展开更多
Two lab-scale reactors, suspended-sludge and fluidized.bed, were conducted with the feed of ammonium-rich synthetic wastewater devoid of COD. Completely autotrophic nitrogen-removal process was fulfilled in both react...Two lab-scale reactors, suspended-sludge and fluidized.bed, were conducted with the feed of ammonium-rich synthetic wastewater devoid of COD. Completely autotrophic nitrogen-removal process was fulfilled in both reactors and the maximum efficiencies of nitrogen removal were achieved, 65% in the suspended-sludge reactor and 73% in the fluidized-bed reactor respectively. Different from the steady performance of the fluldized-bed reactor, the suspended-sludge reactor came to deteriorate constantly after a period of stable operation, resulting in almost complete loss of the N-removal ability in the suspending system. Molecular methods such as PCR and FISH were employed for describing the microbial characteristics in two systems. This study suggests that a biofllm system is a suitable configuration for completely autotrophic N-removal with more feasibility and stability than a suspending system.展开更多
In the present study, the applicability of the wet waste collected from shrimp(Litopenaeus vannamei) to the culture of sea cucumber(Stichopus monotuberculatus) was determined. The effects of dietary wet shrimp waste o...In the present study, the applicability of the wet waste collected from shrimp(Litopenaeus vannamei) to the culture of sea cucumber(Stichopus monotuberculatus) was determined. The effects of dietary wet shrimp waste on the survival, specific growth rate(SGR), fecal production rate(FPR), ammonia- and nitrite-nitrogen productions of sea cucumber were studied. The total organic matter(TOM) level in the feces of sea cucumber was compared with that in corresponding feeds. Diet C(50% wet shrimp waste and 50% sea mud mash) made sea cucumber grow faster than other diets. Sea cucumber fed with either diet D(25% wet shrimp waste and 75% sea mud mash) or sole sea mud exhibited negative growth. The average lowest total FPR of sea cucumber occurred in diet A(wet shrimp waste), and there was no significant difference in total FPR between diet C and diet E(sea mud mash)(P > 0.05). The average ammonia-nitrogen production of sea cucumber in different diet treatments decreased gradually with the decrease of crude protein content in different diets. The average highest nitrite-nitrogen production occurred in diet E treatment, and there was no significant difference in nitrite-nitrogen production among diet A, diet B(75% wet shrimp waste and 25% sea mud mash) and diet C treatments(P > 0.05). In each diet treatment, the total organic matter(TOM) level in feces decreased to different extent compared with that in corresponding feeds.展开更多
Lab scale biological treatment system was constructed from acrylic and operated using synthetic wastewater to evaluate the nitrification performance using different media. The media used for were Ceramic Ring A （CRA...Lab scale biological treatment system was constructed from acrylic and operated using synthetic wastewater to evaluate the nitrification performance using different media. The media used for were Ceramic Ring A （CRA）, Ceramic Ring B （CRB）, Japanese Filter Mat （JFM）, and Filter Wool （FW）. Laboratory studies were conducted, in order to evaluate the nitrification performance of different media types, at different synthetic wastewater flow rates, ranging from 0.03 to 0.045 m3/hr. The results from experiments suggest that at higher water flow rates, there was a decrease in nitrification for all media types. Based on the ammonia and nitrite removal rates, FW media gave the optimum nitrification, of up to 0.46 g/m2/day and 0.09 g/m2/day, respectively. Besides, in this study, the surface texture of the media is the main factor that affected the volumetric ammonia and nitrite conversion rates （VTR and VNR）. JFM gave the greatest VTR and VNR performance, compared with the other media展开更多
The use of the reverse osmosis （RO） process, for refining secondary or tertiary effluent from plants treating domestic wastewater, is rapidly increasing. However, the disposal of the RO reject water poses a problem ...The use of the reverse osmosis （RO） process, for refining secondary or tertiary effluent from plants treating domestic wastewater, is rapidly increasing. However, the disposal of the RO reject water poses a problem due to the presence of very high concentrations of salts, metals, and nutrients in it. This paper contains results of a bench-scale study aimed at reducing nutrients from RO-discarded streams utilizing a sequential bioreactors system, under partial aerobic and anoxic conditions. The tests were performed on synthetic wastewater resembling RO-reject water of an operating treatment plant, with glucose, methanol or acetate added to the water as sources of carbon. Study results indicate that the RO process removed about 50-60% of the total nitrogen and 50% of the phosphate; it reduced chemical oxygen demand （COD） by 79 to 82%, and affected no change in the metal concentrations. A clear cut removal preference for any one of the external carbon sources was not observed, although a slight advantage of glucose and methanol was recorded. The process maintained about 20% of the rector volume in the anoxic environment.展开更多
Loss of ammonia-nitrogen to volatilization and the over application of phosphorus in agricultural wastewaters has led to excess phosphorus build up in topsoil and in surface waters. In order to increase the usable amo...Loss of ammonia-nitrogen to volatilization and the over application of phosphorus in agricultural wastewaters has led to excess phosphorus build up in topsoil and in surface waters. In order to increase the usable amount nitrogen in agricultural wastewaters, the wastewaters underwent a nitrogen treatment process consisting of a hanging basket biological filter. The filters utilized never before used biological growth media, rice hulls, to assist in the formation of a mature biofilms as the oxidation of ammonia to nitrate. The filter design was used on a lab scale that treated both artificial wastewater and dairy parlor wastewater treated with a lime precipitation step for phosphorus treatment. The filters were tested to see if bio-fouling occurred in the filter media bed under high nitrogen loading, if the rice hulls could withstand an extended time frame as bacterial growth media, and to see if the oxidation of ammonia to nitrate would occur. A 50% reduction in ammonia occurred between 30 and 48 hrs in each trial with eventual nitrite oxidation reported in the final two trials. Statistical analysis preformed determined that the ammonia removal rates at the beginning of both the synthetic wastewater and dairy parlor wastewater ten-day tests were statistically similar, but varied toward the end of the trials.展开更多
文摘Dynamic effects of NO2--N accumulation were discussed owing to temperature.In different temperature,a series of vmax and Ks were found considering the relation between the temperature and rate of ammonia nitrogen transforming into NO2--N.The kinetics models,which reflected the conditions of ammonia nitrogen transforming into NO2--N in the treatment process of the coking wastewater,were built up.The characteristic coefficient temperature was determined according to Arrhenius.
文摘Two lab-scale reactors, suspended-sludge and fluidized.bed, were conducted with the feed of ammonium-rich synthetic wastewater devoid of COD. Completely autotrophic nitrogen-removal process was fulfilled in both reactors and the maximum efficiencies of nitrogen removal were achieved, 65% in the suspended-sludge reactor and 73% in the fluidized-bed reactor respectively. Different from the steady performance of the fluldized-bed reactor, the suspended-sludge reactor came to deteriorate constantly after a period of stable operation, resulting in almost complete loss of the N-removal ability in the suspending system. Molecular methods such as PCR and FISH were employed for describing the microbial characteristics in two systems. This study suggests that a biofllm system is a suitable configuration for completely autotrophic N-removal with more feasibility and stability than a suspending system.
基金supported by the Key Projects in the National Science & Technology Pillar Program during the 12th Five-year Plan Period (2011BAD13B02, 2012BAD 18B03)the Science & Technology Promoting Projects for Oceanic & Fishery in Guangdong Province (A2011 00D01, A201101D02)Cooperation Program of Guangdong Province & Chinese Academy of Sciences (2012B091100272)
文摘In the present study, the applicability of the wet waste collected from shrimp(Litopenaeus vannamei) to the culture of sea cucumber(Stichopus monotuberculatus) was determined. The effects of dietary wet shrimp waste on the survival, specific growth rate(SGR), fecal production rate(FPR), ammonia- and nitrite-nitrogen productions of sea cucumber were studied. The total organic matter(TOM) level in the feces of sea cucumber was compared with that in corresponding feeds. Diet C(50% wet shrimp waste and 50% sea mud mash) made sea cucumber grow faster than other diets. Sea cucumber fed with either diet D(25% wet shrimp waste and 75% sea mud mash) or sole sea mud exhibited negative growth. The average lowest total FPR of sea cucumber occurred in diet A(wet shrimp waste), and there was no significant difference in total FPR between diet C and diet E(sea mud mash)(P > 0.05). The average ammonia-nitrogen production of sea cucumber in different diet treatments decreased gradually with the decrease of crude protein content in different diets. The average highest nitrite-nitrogen production occurred in diet E treatment, and there was no significant difference in nitrite-nitrogen production among diet A, diet B(75% wet shrimp waste and 25% sea mud mash) and diet C treatments(P > 0.05). In each diet treatment, the total organic matter(TOM) level in feces decreased to different extent compared with that in corresponding feeds.
文摘Lab scale biological treatment system was constructed from acrylic and operated using synthetic wastewater to evaluate the nitrification performance using different media. The media used for were Ceramic Ring A （CRA）, Ceramic Ring B （CRB）, Japanese Filter Mat （JFM）, and Filter Wool （FW）. Laboratory studies were conducted, in order to evaluate the nitrification performance of different media types, at different synthetic wastewater flow rates, ranging from 0.03 to 0.045 m3/hr. The results from experiments suggest that at higher water flow rates, there was a decrease in nitrification for all media types. Based on the ammonia and nitrite removal rates, FW media gave the optimum nitrification, of up to 0.46 g/m2/day and 0.09 g/m2/day, respectively. Besides, in this study, the surface texture of the media is the main factor that affected the volumetric ammonia and nitrite conversion rates （VTR and VNR）. JFM gave the greatest VTR and VNR performance, compared with the other media
文摘The use of the reverse osmosis （RO） process, for refining secondary or tertiary effluent from plants treating domestic wastewater, is rapidly increasing. However, the disposal of the RO reject water poses a problem due to the presence of very high concentrations of salts, metals, and nutrients in it. This paper contains results of a bench-scale study aimed at reducing nutrients from RO-discarded streams utilizing a sequential bioreactors system, under partial aerobic and anoxic conditions. The tests were performed on synthetic wastewater resembling RO-reject water of an operating treatment plant, with glucose, methanol or acetate added to the water as sources of carbon. Study results indicate that the RO process removed about 50-60% of the total nitrogen and 50% of the phosphate; it reduced chemical oxygen demand （COD） by 79 to 82%, and affected no change in the metal concentrations. A clear cut removal preference for any one of the external carbon sources was not observed, although a slight advantage of glucose and methanol was recorded. The process maintained about 20% of the rector volume in the anoxic environment.
文摘Loss of ammonia-nitrogen to volatilization and the over application of phosphorus in agricultural wastewaters has led to excess phosphorus build up in topsoil and in surface waters. In order to increase the usable amount nitrogen in agricultural wastewaters, the wastewaters underwent a nitrogen treatment process consisting of a hanging basket biological filter. The filters utilized never before used biological growth media, rice hulls, to assist in the formation of a mature biofilms as the oxidation of ammonia to nitrate. The filter design was used on a lab scale that treated both artificial wastewater and dairy parlor wastewater treated with a lime precipitation step for phosphorus treatment. The filters were tested to see if bio-fouling occurred in the filter media bed under high nitrogen loading, if the rice hulls could withstand an extended time frame as bacterial growth media, and to see if the oxidation of ammonia to nitrate would occur. A 50% reduction in ammonia occurred between 30 and 48 hrs in each trial with eventual nitrite oxidation reported in the final two trials. Statistical analysis preformed determined that the ammonia removal rates at the beginning of both the synthetic wastewater and dairy parlor wastewater ten-day tests were statistically similar, but varied toward the end of the trials.
