| People’s production and life are inseparable from the supply of water resources,but China’s per capita water resources are relatively small,and water quality declined significantly year by year.Excessive nitrogen emissions will cause eutrophication of the water body,threaten the safety of residents’ water use,and restrict the sustainable development of the regional economy.Therefore,effective water pollution management,effective management of various types of nitrogen pollution,and reduction of nitrogen concentration in rivers are of great significance in improving the water quality environment and ensuring people’s normal production and life in the context of ecological civilization.However,the water pollution treatment plan for different land uses is currently unclear in Zhejiang Province.This study found that excessive nitrogen emissions from agricultural land and urban construction land is an important source of water pollution in Zhejiang.Among them,agricultural land mainly involves nitrogen emissions from farmland systems and livestock breeding systems,and urban construction land mainly involves nitrogen emissions from human life system.For the treatment of water pollution,on agricultural land,the most effective way is to achieve the optimal management of agriculture through the scale of cultivated land;and for urban land,it is mainly to improve the nitrogen removal efficiency of the wastewater treatment plant(WTP).Combined with data mining and scenario simulation carried out from the aspects of nitrogen utilization,livestock excretion and domestic sewage disposal,this study quantified its environmental benefits for river pollution control in Zhejiang Province and conducted cost-benefit analysis and calculation,taking Zhejiang province,China as a case study.At the same time,from the two levels of agricultural land and urban land,water pollution reduction studies were conducted on the scale of cultivated land and the upgrading of WTPs.The results show that the scenario simulation is in line with expectations,and all three emission reduction ideas are very effective;when the nitrogen utilization efficiency(NUE)is increased to 60%,the fertilizer application amount is greatly reduced,and the nitrogen amount in farmland runoff is reduced by 48%;by strengthening the management of livestock excrement,the reuse of excrement resources can be realized while reducing nitrogen into the river;the most significant reduction was achieved by the management of human life emissions,which reduced the amount of nitrogen discharged into rivers from 260,000 tons to 160,000 tons,a reduction of 35%.In terms of agricultural land,adopting a large-scale agricultural land model,while ensuring stable income growth,can reduce the use of fertilizers on farmland in Zhejiang Province by 31% and the amount of nitrogen in the farmland flowing into the river is reduced by 1/4;on urban land,the improvement of discharge standards and process improvement of wastewater treatment plants can effectively reduce the nitrogen concentration of sewage out of the factory,and the amount of nitrogen discharged into the river from the treatment discharge system is reduced by 18%.Based on the scenario simulation results and analysis of emission reduction measures under different land uses,in order to improve the quality of the water body,in addition to increasing the centralized treatment of livestock and poultry manure and the utilization rate of nitrogen fertilizer,it is more important to increase the domestic wastewater treatment rate and upgrade the sewage discharge standard.Improve people’s dietary habits,raise environmental awareness,and promote the rational use of nitrogen. |
