Among the Chinese lakes with the problem of eutrophication, the Taihu Lake, the Chaohu Lake and the Dianchi Lake have the worst cases of blue algae outbreak, which happen every year. Other lakes also have problems of ...Among the Chinese lakes with the problem of eutrophication, the Taihu Lake, the Chaohu Lake and the Dianchi Lake have the worst cases of blue algae outbreak, which happen every year. Other lakes also have problems of blue algae outbreak at various degrees. However, some lakes don't have such problems. Practices have shown that through comprehensive management, the problem can be basically eliminated or significantly alleviated. "Water bloom" and blue algae outbreak have different connotation. The major factors affecting blue algae outbreak are sources of pollutants and ecological environment. Experiences are summed up and a new thinking on its management is developed: resolving the problem of blue algae is fundamental to lake management and development goals should be clearly set forth so as to eventually build a healthy aquatic ecosys- tem. The problem of blue algae can't be fully tackled by solely relying on the management of eutrophication but only by combining efforts of reducing the amount of blue algae and the management of eutrophication. The number of reduced blue algae should be larger than that of naturally prolifera- ted algae so as to alleviate and eliminate the problem of blue algae outbreak. Various engineering and technical measures and relevant protective procedures should be carried out in a scientific and proper manner. The total amount of nitrogen and phosphorous entering the lake either from point-source or non-point source pollution should be substantially reduced. Controlling the source of pollution and intercepting pollutants are the bas- ic measures. Wastewater treatment plant is the largest point source pollution in the future and adequate plants should be built with improved emission standards. Meanwhile, other measures including fishing out blue algae, diverting water, dredging, ecological restoration and expanding reed zone, should be implemented to alleviate the problem of eutrophication and eventually eliminate the problem of blue algae outbreak.展开更多
In this study two types of biological contact oxidation processes(BCOP),a step-feed(SBCOP)unit and an inter-recycle(IBCOP)unit,were designed to investigate the treatment of heavily polluted river water.The Daqing Rive...In this study two types of biological contact oxidation processes(BCOP),a step-feed(SBCOP)unit and an inter-recycle(IBCOP)unit,were designed to investigate the treatment of heavily polluted river water.The Daqing River,which is the largest pollutant contributor to the Dianchi Lake,one of the most eutrophic freshwater lakes in China,was taken for the case study.It was found that the SBCOP had higher adaptability and better performance in the reduction of COD,TN,and TP,which made it applicable for the treatment of polluted river water entering the Dianchi Lake.Nitrification rate was observed to be greatly affected by the influent temperature.During each season,the nitrification in the SBCOP was higher than that in the IBCOP.TN removal efficiency in the SBCOP was higher than that in the IBCOP during the winter and spring but poorer during the summer,possibly due to the inhibition of denitrification by higher dissolved oxygen level in the summer.Moreover,symbiotic algaebacteria growth may be conducive to the removal of pollutants.展开更多
Effects of human activity on the distribution of phosphorus(P)forms were investigated for the sediments and porewaters in Daqinghe Estuary of Dianchi Lake,China.The concentrations of total P(TP),inorganic-P(IP),and or...Effects of human activity on the distribution of phosphorus(P)forms were investigated for the sediments and porewaters in Daqinghe Estuary of Dianchi Lake,China.The concentrations of total P(TP),inorganic-P(IP),and organic-P(Org-P),and the ratio of iron-bound P(Fe-P)/calcium-bound P(Ca-P)in the sediments decreased with the increasing distance from the sampling site to the estuary.This is probably due to the flocculant materials,e.g.,ferric and aluminous salts,usually being added in the wastewater treatment processes.The concentration of ammonia in the sediment porewaters significantly decreased with the increasing distance from the sampling site to the estuary.Both concentrations of total nitrogen and nitrogen in the sediment porewaters decreased to some content with the increasing distance from the sampling site to the estuary.However,the concentrations of nitrate,dissolved total P(DTP),and TP did not have strong relationship with the distances from the sampling sites to the estuary.Pollution load and water quantity also had an important influence on the concentrations of P in sediments and its interstitial water in estuary sedimentary area.展开更多
文摘Among the Chinese lakes with the problem of eutrophication, the Taihu Lake, the Chaohu Lake and the Dianchi Lake have the worst cases of blue algae outbreak, which happen every year. Other lakes also have problems of blue algae outbreak at various degrees. However, some lakes don't have such problems. Practices have shown that through comprehensive management, the problem can be basically eliminated or significantly alleviated. "Water bloom" and blue algae outbreak have different connotation. The major factors affecting blue algae outbreak are sources of pollutants and ecological environment. Experiences are summed up and a new thinking on its management is developed: resolving the problem of blue algae is fundamental to lake management and development goals should be clearly set forth so as to eventually build a healthy aquatic ecosys- tem. The problem of blue algae can't be fully tackled by solely relying on the management of eutrophication but only by combining efforts of reducing the amount of blue algae and the management of eutrophication. The number of reduced blue algae should be larger than that of naturally prolifera- ted algae so as to alleviate and eliminate the problem of blue algae outbreak. Various engineering and technical measures and relevant protective procedures should be carried out in a scientific and proper manner. The total amount of nitrogen and phosphorous entering the lake either from point-source or non-point source pollution should be substantially reduced. Controlling the source of pollution and intercepting pollutants are the bas- ic measures. Wastewater treatment plant is the largest point source pollution in the future and adequate plants should be built with improved emission standards. Meanwhile, other measures including fishing out blue algae, diverting water, dredging, ecological restoration and expanding reed zone, should be implemented to alleviate the problem of eutrophication and eventually eliminate the problem of blue algae outbreak.
基金This study was supported by the National High Technology Research and Development Program of China(863 Program)(Grant No.2005AA601010-03)the National Natural Science Foundation of China(Grant No.50778001).
文摘In this study two types of biological contact oxidation processes(BCOP),a step-feed(SBCOP)unit and an inter-recycle(IBCOP)unit,were designed to investigate the treatment of heavily polluted river water.The Daqing River,which is the largest pollutant contributor to the Dianchi Lake,one of the most eutrophic freshwater lakes in China,was taken for the case study.It was found that the SBCOP had higher adaptability and better performance in the reduction of COD,TN,and TP,which made it applicable for the treatment of polluted river water entering the Dianchi Lake.Nitrification rate was observed to be greatly affected by the influent temperature.During each season,the nitrification in the SBCOP was higher than that in the IBCOP.TN removal efficiency in the SBCOP was higher than that in the IBCOP during the winter and spring but poorer during the summer,possibly due to the inhibition of denitrification by higher dissolved oxygen level in the summer.Moreover,symbiotic algaebacteria growth may be conducive to the removal of pollutants.
基金the National Basic Research Program of China(973 Program)(Grant No.2008CB418200)the National High Technology Research and Development Program of China(863 Program)(Grant Nos.2008ZX07101 and 2005AA60101005。
文摘Effects of human activity on the distribution of phosphorus(P)forms were investigated for the sediments and porewaters in Daqinghe Estuary of Dianchi Lake,China.The concentrations of total P(TP),inorganic-P(IP),and organic-P(Org-P),and the ratio of iron-bound P(Fe-P)/calcium-bound P(Ca-P)in the sediments decreased with the increasing distance from the sampling site to the estuary.This is probably due to the flocculant materials,e.g.,ferric and aluminous salts,usually being added in the wastewater treatment processes.The concentration of ammonia in the sediment porewaters significantly decreased with the increasing distance from the sampling site to the estuary.Both concentrations of total nitrogen and nitrogen in the sediment porewaters decreased to some content with the increasing distance from the sampling site to the estuary.However,the concentrations of nitrate,dissolved total P(DTP),and TP did not have strong relationship with the distances from the sampling sites to the estuary.Pollution load and water quantity also had an important influence on the concentrations of P in sediments and its interstitial water in estuary sedimentary area.