The quality and safety of residents’water rely heavily on the design of municipal water supply and drainage pipes.Therefore,this paper aims to enhance the optimization of municipal water supply and drainage pipe desi...The quality and safety of residents’water rely heavily on the design of municipal water supply and drainage pipes.Therefore,this paper aims to enhance the optimization of municipal water supply and drainage pipe design by focusing on design requirements,principles,and key elements.Drawing from relevant design optimization experiences,technology advancements,and optimization measures,the research will analyze and consolidate the essential aspects of municipal water supply and drainage pipe design.The goal is to fundamentally elevate the quality standards of these designs,ensuring they meet the criteria for engineering project excellence.Through this comprehensive approach,we aim to contribute to the improvement and sustainability of water supply and drainage systems,safeguarding the well-being of residents.展开更多
To evaluate the removal efficiency of organic pollutants in the sewage by Harbin municipal sewage treatment plant, the influent and effluent samples from the plant were pretreated by liquid-liquid extraction （LLE） u...To evaluate the removal efficiency of organic pollutants in the sewage by Harbin municipal sewage treatment plant, the influent and effluent samples from the plant were pretreated by liquid-liquid extraction （LLE） under conditions of acidity, neutrality and alkaleseence in sequence, and then were analyzed by gas chromatograph-mass spectrum （GC-MS） procedures. Results indicate that there are 70 species of organic pollutants in the influent sample of the plant, which mainly consist of alkyls, benzene series, esters, and heteroeyclic compounds. Some of these organic pollutants are biotoxie and belong to persistent organic pollutants （POPs）. Four species among them are on the list of Prior Pollutants of Environmental Protection Agency of USA （USEPA）. However, 7 species of organic pollutants appearing in the effluent sample mainly include alkyls of multi-carbons and phthalate esters. The removal efficiency of phthalates is poor because of their poor biodegradability. The sewage treatment technique is effective in removing most＋of organics pollutants.展开更多
To evaluate the nitrogen pollution load in an aquifer, a water and nitrogen balance analysis was conducted over a thirty-five year period at five yearly intervals. First, we established a two-horizon model comprising ...To evaluate the nitrogen pollution load in an aquifer, a water and nitrogen balance analysis was conducted over a thirty-five year period at five yearly intervals. First, we established a two-horizon model comprising a channel/soil horizon, and an aquifer horizon, with exchange of water between the aquifer and river. The nitrogen balance was estimated from the product of nitrogen concentration and water flow obtained from the water balance analysis. The aquifer nitrogen balance results were as follows: 1) In the aquifer horizon, the total nitrogen pollution load potential (NPLP) peaked in the period 1981-1990 at 1800 t·yr-1;following this the NPLP rapidly decreased to about 600 t·yr-1 in the period 2006-2010. The largest NPLP input component of 1000 t·yr-1 in the period 1976-1990 was from farmland. Subsequently, farmland NPLP decreased to only 400 t·yr-1 between 2006 and 2010. The second largest input component, 600 t·yr-1, was effluent from wastewater treatment works (WWTWs) in the period 1986-1990;this also decreased markedly to about 100 t·yr-1 between 2006 and 2010;2) The difference between input and output in the aquifer horizon, used as an index of groundwater pollution, peaked in the period 1986-1990 at about 1200 t·yr-1. This gradually decreased to about 200 t·yr-1 by 2006-2010. 3) The temporal change in NPLP coincided with the nitrogen concentration of the rivers in the study area. In addition, nitrogen concentrations in two test wells were 1.0 mg·l-1 at a depth of 150 m and only 0.25 mg·l-1 at 50 m, suggesting gradual percolation of the nitrogen polluted water deeper in the aquifer.展开更多
文摘The quality and safety of residents’water rely heavily on the design of municipal water supply and drainage pipes.Therefore,this paper aims to enhance the optimization of municipal water supply and drainage pipe design by focusing on design requirements,principles,and key elements.Drawing from relevant design optimization experiences,technology advancements,and optimization measures,the research will analyze and consolidate the essential aspects of municipal water supply and drainage pipe design.The goal is to fundamentally elevate the quality standards of these designs,ensuring they meet the criteria for engineering project excellence.Through this comprehensive approach,we aim to contribute to the improvement and sustainability of water supply and drainage systems,safeguarding the well-being of residents.
文摘To evaluate the removal efficiency of organic pollutants in the sewage by Harbin municipal sewage treatment plant, the influent and effluent samples from the plant were pretreated by liquid-liquid extraction （LLE） under conditions of acidity, neutrality and alkaleseence in sequence, and then were analyzed by gas chromatograph-mass spectrum （GC-MS） procedures. Results indicate that there are 70 species of organic pollutants in the influent sample of the plant, which mainly consist of alkyls, benzene series, esters, and heteroeyclic compounds. Some of these organic pollutants are biotoxie and belong to persistent organic pollutants （POPs）. Four species among them are on the list of Prior Pollutants of Environmental Protection Agency of USA （USEPA）. However, 7 species of organic pollutants appearing in the effluent sample mainly include alkyls of multi-carbons and phthalate esters. The removal efficiency of phthalates is poor because of their poor biodegradability. The sewage treatment technique is effective in removing most＋of organics pollutants.
文摘To evaluate the nitrogen pollution load in an aquifer, a water and nitrogen balance analysis was conducted over a thirty-five year period at five yearly intervals. First, we established a two-horizon model comprising a channel/soil horizon, and an aquifer horizon, with exchange of water between the aquifer and river. The nitrogen balance was estimated from the product of nitrogen concentration and water flow obtained from the water balance analysis. The aquifer nitrogen balance results were as follows: 1) In the aquifer horizon, the total nitrogen pollution load potential (NPLP) peaked in the period 1981-1990 at 1800 t·yr-1;following this the NPLP rapidly decreased to about 600 t·yr-1 in the period 2006-2010. The largest NPLP input component of 1000 t·yr-1 in the period 1976-1990 was from farmland. Subsequently, farmland NPLP decreased to only 400 t·yr-1 between 2006 and 2010. The second largest input component, 600 t·yr-1, was effluent from wastewater treatment works (WWTWs) in the period 1986-1990;this also decreased markedly to about 100 t·yr-1 between 2006 and 2010;2) The difference between input and output in the aquifer horizon, used as an index of groundwater pollution, peaked in the period 1986-1990 at about 1200 t·yr-1. This gradually decreased to about 200 t·yr-1 by 2006-2010. 3) The temporal change in NPLP coincided with the nitrogen concentration of the rivers in the study area. In addition, nitrogen concentrations in two test wells were 1.0 mg·l-1 at a depth of 150 m and only 0.25 mg·l-1 at 50 m, suggesting gradual percolation of the nitrogen polluted water deeper in the aquifer.
