[Objective] The study aimed to research the nutrients release of ponds sediment.[Method] The sediments which from a new pond(A) and an old one (B) these analyses used to carry out indoor experiment under the anaerobic...[Objective] The study aimed to research the nutrients release of ponds sediment.[Method] The sediments which from a new pond(A) and an old one (B) these analyses used to carry out indoor experiment under the anaerobic dark condition for researching on nutrient release. The N(nitrogenous) and P(phosphorous) release were analyzed every two days.[Result] At the prophase, the N release in B was bigger than that in A, while the decline sediment release in A was gentle.[Conclusion] There was no accumulation of organic compound during the breeding time. The NH4-N was the main form of N release; and the P release was correlated with N release, while PO4-P was the main form of P release.展开更多
Two short sediment cores named ZS and THS dated by the 210Pb or 137Cs method were collected from the northwest and southwest of Taihu Lake respectivly,and total organic carbon(TOC) and nutrients including total nitrog...Two short sediment cores named ZS and THS dated by the 210Pb or 137Cs method were collected from the northwest and southwest of Taihu Lake respectivly,and total organic carbon(TOC) and nutrients including total nitrogen(TN) and total phosphorus(TP) were determined to analyze the chronology and nutrients change in recent sediment.The results show that 137Cs activities are low(less than 15 Bq/kg) in the two cores,attributed to the 137Cs migration.Based on 210Pb constant rate of supply(CRS) model,the sedimentation accumulation rates range from 0.13 g/(cm2·yr) to 0.76 g/(cm2·yr) in the ZS core,and from 0.10 g/(cm2·yr) to 0.56 g/(cm2·yr) in the THS core.A remarkable increase in organic matter and nutrients has occurred in the two dated cores since the mid-1980s.The historical changes of organic matter and nutrients in the two cores are consisitent with the monitoring data for surface sediment after the 1960s.The TP accumulation rates after the early 1980s are 0.97 and 0.92 times higher than those from the 1950s to the 1980s in ZS and THS cores,respectively.Higher TP concentrations in the past two-decade deposits of Taihu Lake are due to both diagenetic factors and human activities.展开更多
A pilot-scale modified carbon source division anaerobic anoxic oxic(AAO) process with pre-concentration of returned activated sludge(RAS) was proposed in this study for the enhanced biological nutrient removal(BNR) of...A pilot-scale modified carbon source division anaerobic anoxic oxic(AAO) process with pre-concentration of returned activated sludge(RAS) was proposed in this study for the enhanced biological nutrient removal(BNR) of municipal wastewater with limited carbon source. The influent carbon source was fed in step while a novel RAS pre-concentration tank was adopted to improve BNR efficiency, and the effects of an influent carbon source distribution ratio and a RAS pre-concentration ratio were investigated. The results show that the removal efficiency of TN is mainly influenced by the carbon source distribution ratio while the TP removal relies on the RAS pre-concentration ratio. The optimum carbon source distribution ratio and RAS pre-concentration ratio are 60% and 50%, respectively, with an inner recycling ratio of 100% under the optimum steady operation of pilot test, reaching an average effluent TN concentration of 9.8 mg·L-1with a removal efficiency of 63% and an average TP removal efficiency of 94%. The mechanism of nutrient removal is discussed and the kinetics is analyzed. The results reveal that the optimal carbon source distribution ratio provides sufficient denitrifying carbon source to each anoxic phase, reducing nitrate accumulation while the RAS pre-concentration ratio improves the condition of anaerobic zone to ensure the phosphorus release due to less nitrate in the returned sludge. Therefore, nitrifying bacteria, denitrifying bacteria and phosphorus accumulation organisms play an important role under the optimum condition, enhancing the performance of nutrient removal in this test.展开更多
A field survey was carried out to collect monthly samples from sewage sludge beds. The samples were collected from three sewage treatment plants namely; Jahra, Rekka, and Um Al-Hayman; over 12 months＇ period started ...A field survey was carried out to collect monthly samples from sewage sludge beds. The samples were collected from three sewage treatment plants namely; Jahra, Rekka, and Um Al-Hayman; over 12 months＇ period started from January and ended by December 2002, 2004 and 2006 to assess the temporal changes on the pollutants associated with sewage sludge. The collected samples were analyzed for organic matters, nutrients and heavy metals. It was observed that the quantities of organic matter, organic carbon and nutrients were varied in a wide range of values. The levels of heavy metals were generally below than reported by the Kuwait Environment Public Authority Limits for application of dry sludge. Temporal changes in the levels of heavy metals and other pollutants may be affected by temporal variation in the level of heavy metals, nutrients and organic matters in the influent of wastewater or in the efficiency of the treatment involved.展开更多
Land utilization is considered as a positive and effective method for sewage sludge disposal. This method takes use of a large number of rich nutrients for soil and crop. The application of sewage sludge in soil incre...Land utilization is considered as a positive and effective method for sewage sludge disposal. This method takes use of a large number of rich nutrients for soil and crop. The application of sewage sludge in soil increases the concentration of heavy metals. Compared with 15-30 cm layer of soil, 0-15 cm layer increased significantly, especially for Cu, Zn and Ni. The concentration of Cd in soil is considered as the main limiting factor, which determines the years of land utilization. If the largest continuous application is 30 t/（hm2.a） to the soil, the largest application period will be 11.53 years. In this paper, set pair analysis model are used in safety evaluation of the soil. After one year application of sewage, the soil can be still safe. Finally, according to the process of the subject put forward some suggestions.展开更多
Sludge production is an avoidable problem arising from the treatment of wastewater. The sludge remained after municipal wastewater treatment contains considerable amounts of various contaminants and if is not properly...Sludge production is an avoidable problem arising from the treatment of wastewater. The sludge remained after municipal wastewater treatment contains considerable amounts of various contaminants and if is not properly handled and disposed, it may produce extensive health hazards. On the other hand, this sludge has benefit for plants and soils. Sludge samples were collected over a 12 month period from sewage treatment plants （STP＇s）, i.e, Khairathabad and Meeralam Tank, Hyderabad, India and analyzed for C, H, N, S by elementar analyzer, P, K, Ca, Mg by spectrophotometer and heavy metals like Zn, Pb, Ni, Cu, Cd by atomic absorption spectrophotometer. The sludge contained approximately 50% organic matter and 1-4% inorganic carbon. Organic and inorganic carbon, organic nitrogen, inorganic phosphorous, Ca and Mg were found to be present in sludge at a relatively constant concentration with respect to sampling time. Inorganic N, organic P, K, and all metals were found to be quite variable with time when sludge produced from different STP＇s.展开更多
Eutrophication in the Three Gorges Reservoir has become a serious issue, and phosphorus (P) is the nutrient thought to be primarily responsible although there are few studies about P loss from the mostly sloping farml...Eutrophication in the Three Gorges Reservoir has become a serious issue, and phosphorus (P) is the nutrient thought to be primarily responsible although there are few studies about P loss from the mostly sloping farmlands of the area. This work investigated the amounts and forms of P loss from 9 farmlands with the slopes of 4°, 9°, and 17° in a small watershed, Wangjiagou in Fuling District, Chongqing of China. The slope of the relationship between runoff and rainfall increased with field slope; i.e., there was a significant interaction between the effects of rainfall and field slope on water export. For sediment export by surface runoff, there was no interaction between field slope and rainfall, and the intercept of the relationship between rainfall and sediment loss was significantly different for the 3 slopes. The main P loss was from sediments, regardless of slope. In the runoff water, particulate P was the largest P fraction, and its loss was greatest from the steepest land and least from the flattest. The release of total P and available P from sediments followed the same trend. The P loss during May to July in Wangjiagou was more than 60% of the annual total.展开更多
基金Supported by the National High Technology Research and Development Program of China (863 Program)(2007AA10Z239)the National Key Technology R&D Program(2006BAD03B0102)+2 种基金the Natural Science Foundation of Guangdong Province(5004159)Scienceand Technology Planning Project of Guangdong Province(2005N33201012)the Open Fund of Key Laboratory of Genetic Breeding and Aquaculture Biology of Freshwater Fishes,Ministry of Agriculture(BM2007-03)~~
文摘[Objective] The study aimed to research the nutrients release of ponds sediment.[Method] The sediments which from a new pond(A) and an old one (B) these analyses used to carry out indoor experiment under the anaerobic dark condition for researching on nutrient release. The N(nitrogenous) and P(phosphorous) release were analyzed every two days.[Result] At the prophase, the N release in B was bigger than that in A, while the decline sediment release in A was gentle.[Conclusion] There was no accumulation of organic compound during the breeding time. The NH4-N was the main form of N release; and the P release was correlated with N release, while PO4-P was the main form of P release.
基金Under the auspices of National Key Science and Technology Special Program of Water Pollution Control and Treatment (No. 2008ZX07101-012-01)National Natural Science Foundation of China (No. 40902048, 40771197)Jiangsu Natural Sci-ence Foundation (No. BK2009331, BE2008690)
文摘Two short sediment cores named ZS and THS dated by the 210Pb or 137Cs method were collected from the northwest and southwest of Taihu Lake respectivly,and total organic carbon(TOC) and nutrients including total nitrogen(TN) and total phosphorus(TP) were determined to analyze the chronology and nutrients change in recent sediment.The results show that 137Cs activities are low(less than 15 Bq/kg) in the two cores,attributed to the 137Cs migration.Based on 210Pb constant rate of supply(CRS) model,the sedimentation accumulation rates range from 0.13 g/(cm2·yr) to 0.76 g/(cm2·yr) in the ZS core,and from 0.10 g/(cm2·yr) to 0.56 g/(cm2·yr) in the THS core.A remarkable increase in organic matter and nutrients has occurred in the two dated cores since the mid-1980s.The historical changes of organic matter and nutrients in the two cores are consisitent with the monitoring data for surface sediment after the 1960s.The TP accumulation rates after the early 1980s are 0.97 and 0.92 times higher than those from the 1950s to the 1980s in ZS and THS cores,respectively.Higher TP concentrations in the past two-decade deposits of Taihu Lake are due to both diagenetic factors and human activities.
基金Supported by the Major Science and Technology Program for Water Pollution Contro and Treatment-Crucial Technology Research and Engineering Sample Subject on Municipa Wastewater Treatment Process Updated to Higher Drainage Standard(2008ZX07317-02)Wuhan Water Pollution Control and the Water Environment Administer Technology and Synthetic Sample Project in Cities and Towns(2008ZX07317)
文摘A pilot-scale modified carbon source division anaerobic anoxic oxic(AAO) process with pre-concentration of returned activated sludge(RAS) was proposed in this study for the enhanced biological nutrient removal(BNR) of municipal wastewater with limited carbon source. The influent carbon source was fed in step while a novel RAS pre-concentration tank was adopted to improve BNR efficiency, and the effects of an influent carbon source distribution ratio and a RAS pre-concentration ratio were investigated. The results show that the removal efficiency of TN is mainly influenced by the carbon source distribution ratio while the TP removal relies on the RAS pre-concentration ratio. The optimum carbon source distribution ratio and RAS pre-concentration ratio are 60% and 50%, respectively, with an inner recycling ratio of 100% under the optimum steady operation of pilot test, reaching an average effluent TN concentration of 9.8 mg·L-1with a removal efficiency of 63% and an average TP removal efficiency of 94%. The mechanism of nutrient removal is discussed and the kinetics is analyzed. The results reveal that the optimal carbon source distribution ratio provides sufficient denitrifying carbon source to each anoxic phase, reducing nitrate accumulation while the RAS pre-concentration ratio improves the condition of anaerobic zone to ensure the phosphorus release due to less nitrate in the returned sludge. Therefore, nitrifying bacteria, denitrifying bacteria and phosphorus accumulation organisms play an important role under the optimum condition, enhancing the performance of nutrient removal in this test.
文摘A field survey was carried out to collect monthly samples from sewage sludge beds. The samples were collected from three sewage treatment plants namely; Jahra, Rekka, and Um Al-Hayman; over 12 months＇ period started from January and ended by December 2002, 2004 and 2006 to assess the temporal changes on the pollutants associated with sewage sludge. The collected samples were analyzed for organic matters, nutrients and heavy metals. It was observed that the quantities of organic matter, organic carbon and nutrients were varied in a wide range of values. The levels of heavy metals were generally below than reported by the Kuwait Environment Public Authority Limits for application of dry sludge. Temporal changes in the levels of heavy metals and other pollutants may be affected by temporal variation in the level of heavy metals, nutrients and organic matters in the influent of wastewater or in the efficiency of the treatment involved.
文摘Land utilization is considered as a positive and effective method for sewage sludge disposal. This method takes use of a large number of rich nutrients for soil and crop. The application of sewage sludge in soil increases the concentration of heavy metals. Compared with 15-30 cm layer of soil, 0-15 cm layer increased significantly, especially for Cu, Zn and Ni. The concentration of Cd in soil is considered as the main limiting factor, which determines the years of land utilization. If the largest continuous application is 30 t/（hm2.a） to the soil, the largest application period will be 11.53 years. In this paper, set pair analysis model are used in safety evaluation of the soil. After one year application of sewage, the soil can be still safe. Finally, according to the process of the subject put forward some suggestions.
文摘Sludge production is an avoidable problem arising from the treatment of wastewater. The sludge remained after municipal wastewater treatment contains considerable amounts of various contaminants and if is not properly handled and disposed, it may produce extensive health hazards. On the other hand, this sludge has benefit for plants and soils. Sludge samples were collected over a 12 month period from sewage treatment plants （STP＇s）, i.e, Khairathabad and Meeralam Tank, Hyderabad, India and analyzed for C, H, N, S by elementar analyzer, P, K, Ca, Mg by spectrophotometer and heavy metals like Zn, Pb, Ni, Cu, Cd by atomic absorption spectrophotometer. The sludge contained approximately 50% organic matter and 1-4% inorganic carbon. Organic and inorganic carbon, organic nitrogen, inorganic phosphorous, Ca and Mg were found to be present in sludge at a relatively constant concentration with respect to sampling time. Inorganic N, organic P, K, and all metals were found to be quite variable with time when sludge produced from different STP＇s.
基金Supported by the National Key Technologies Research and Development Program of the Ministry of Science and Technology of China during the 12th Five-Year Plan Period (No. 2012BAD141318)
文摘Eutrophication in the Three Gorges Reservoir has become a serious issue, and phosphorus (P) is the nutrient thought to be primarily responsible although there are few studies about P loss from the mostly sloping farmlands of the area. This work investigated the amounts and forms of P loss from 9 farmlands with the slopes of 4°, 9°, and 17° in a small watershed, Wangjiagou in Fuling District, Chongqing of China. The slope of the relationship between runoff and rainfall increased with field slope; i.e., there was a significant interaction between the effects of rainfall and field slope on water export. For sediment export by surface runoff, there was no interaction between field slope and rainfall, and the intercept of the relationship between rainfall and sediment loss was significantly different for the 3 slopes. The main P loss was from sediments, regardless of slope. In the runoff water, particulate P was the largest P fraction, and its loss was greatest from the steepest land and least from the flattest. The release of total P and available P from sediments followed the same trend. The P loss during May to July in Wangjiagou was more than 60% of the annual total.
