Source Analysis Of Typical Regional Environmental Loads Based On SFA

In recent years,ecological environment is very poor in China.The problems of environmental pollution caused by nitrogen,phosphorus and sulfur are particularly prominent.In order to essentially solve these problems,it is indispensable to study nitrogen,phosphorus and sulfur material metabolism.The studies on material metabolism of elements were mainly focused on the country,city and enterprise,while there were few provincial-level researches.In addition,the control and management of the end pollution discharge drawn much attention,while analyzing and solving environmental problems from the pollution source were neglected.Combining substance flow analysis(SFA)with material flow analysis(MFA),the material metabolism analysis was introduced for provincial-level to analyze the cause of environmental loads in essence,which included defining metabolism system boundaries,generalizing metabolism system framework,determining elemental metabolic pathways,establishing elemental metabolic topologies and constructing calculation models.Then,this analysis method was applied to Liaoning Province to study material metabolism of nitrogen,phosphorus and sulfur.And the effects of nitrogen,phosphorus and sulfur on ecological environment were analyzed from three aspects:industrial,agricultural and residential life subsystem.Finally,the combined analysis of nitrogen,phosphorus and sulfur metabolism was carried out to identify the key flows and links in the metabolic structure and to analyze the causes of environmental loads from material metabolism process.Based on those,some countermeasures were put forward in this paper to reduce the heavy environmental loads.The results show that the socio-economic system in Liaoning Province was a open linear system.In 2013,metabolic fluxes of nitrogen,phosphorus and sulfur were 5.34 million tons,0.58 million tons and 3.08 million tons respectively.And the environmental loads of nitrogen,phosphorus and sulfur were 2.14 million tons,0.3 million tons,and 1.16 million tons respectively.Agriculture was the key link of water loads,accounting for 61.8%and 80.2%in nitrogen and phosphorus loads in water bodies in Liaoning Province respectively.And livestock and poultry breeding industry was major water nitrogen-emission and phosphorus-emission industry,which accounted for 90.7%and 95.7%in nitrogen and phosphorus loads in water bodies in agriculture respectively.Industry was the key link of atmospheric loads,accounting for 37.8%and 91.4%in nitrogen and sulfur loads in the atmosphere in Liaoning Province respectively.And electricity,heat production and supply industry was major atmosphere nitrogen-emission and sulfur-emission industry,which accounted for 37.4%and 42.5%in nitrogen and sulfur loads in the atmosphere in industry respectively.Industry was the key link of soil loads,accounting for 68.9%and 90%in nitrogen and sulfur loads in the soil in Liaoning Province respectively.And agriculture accounted for 85.3%in phosphorus loads in the soil in Liaoning Province.Compared with industrial wastewater,domestic sewage was the key flow of water loads,which was 6.5 times,13.2 times and 4.9 times of industrial wasterwater in the nitrogen,phosphorus and sulfur loads in water bodies respectively.The removal ratios of nitrogen,phosphorus and sulfur were 22%,37%and 32%respectively,while the concentration of domestic sewage was 86.8%in Liaoning Province.Therefore,it is efficient to reduce the environmental load by controlling substance input,closing waste loop and enhancing production efficiency of the substance.