Phosphorus Flow Analysis In The Socio-economic System Of City Within Lake Basin

The lake pollution by the anthropogenic sources is becoming increasingly serious due to the rapid growth of economy and population in the lake basin. Especially, eutrophication has been one of the most severe lake pollution problems in China, and been paying more and more attention by Central Government. Strengthening eutrophication management is the key issue for lake pollution control. As we know, nitrogen (N) and phosphorous (P) are two elements essential for the growth and development of life. However, in excess they can have negative environmental impacts such as eutrophication of surface waters. Phosphorus has been linked with water quality problems in that it contributes a lot to eutrophication. Understanding the flow of phosphorus through the urban environment within lake basin is vital to urban sustainability and successful water pollution control strategies for lake. If so, how to precisely identify the causes for surface and groundwater pollution and formulate the most efficient means to avoid them? It is important to know the main flows in the system, the form of emission, the transformation process, and the accounting method of the flows.The substance flow analysis (SFA) method was employed to examine phosphorus flow and its connection to water pollution in the city of Hefei, in Chaohu Lake Basin of China, in 2008. The study provides a conceptual framework for analyzing an anthropogenic phosphorus cycle that includes four stages:extraction, fabrication & manufacturing, use, and waste management. Estimates of phosphorus flow were based on existing data as well as field research, expert advice, local accounting systems, and literature.The total phosphorus input into Hefei in 2008 reached 7,849 tons. Approximately 1582 tons P was discharged as waste to surface water. Effluent containing excessive fertilizer from Farming operations plays an important role in phosphorus overloads onto surface water (64.5% of total emissions); the other major emission source is sewage discharge (24.6% of total emissions). Based on the cost-effective method, we assess the effect of the four phosphorus reduction practices-formula fertilization by soil testing, constructed wetlands, subsurface wastewater infiltration system, WWTPs.We provide some suggestions for reducing phosphorus emissions. Increasingly intensive fertilizer use in plant production has an impact on the total flow of phosphorus, causing more than 30% of P leaching in 2008. Therefore, the most effective means of preventing phosphorus discharge into surface waters is to use phosphate fertilizer more effectively, and artificial wetlands have been suggested for the control of phosphorus loss from non-point source. An increase in population, especially in respect to urban populations and consequent urban lifestyles, has made food production and consumption an important issue for environmental quality and sustainability. The most favorable option is to change both human behavior and the established treatment system as this has been shown to achieve a significant improvement in phosphorus management. At the same time, the animal intake and manure production are quite significant and require further attention in the context of nutrient management.