| Fenghe river is the water source of Heihe river water diversion project of Xi'an,and it is also the important centralized domestic drinking water source of Chang'an urban residents and the industrial and agricultural production.According to the“Guanzhong and Tianshui development planning" that approved by the State Council in 2009,the government of Shaanxi province decided to establish Xi-Xian new district.The Feng-Wei new district is an important part of Xi-Xian new district.Fully combining the construction of Fenghe river transform and the Feng-Wei new district and thus making Fenghe river become a river manifested city ecological culture such as "the Blue Danube",which is the planning idea of the Feng-Wei new district.Accordingly,the healthy and water safety and the implementation process of Feng-Wei new district total plan depend on the water quality of Fenghe river.The existing research results show that the organic contamination is the more pollution of Fenghe river and ammonia nitrogen is one of the key pollutants.Non-point source pollution is an important factor of river pollution.It has important significance to analyze the non-point source pollution characteristics and nitrogen source of the river basin and formulate the corresponding prevention and control measures for river pollution control.The research and analysis of non-point source pollution characteristics of Fengheriver basin was based on the simultaneous monitoring and water quality and hydrologic data of quality and quantity of water,also combined with field investigation.On this basis,the long series non-point source pollution loads are estimated,and the different pollution source ammonia nitrogen and nitre nitrogen isotope composition are investigated using the nitrogen isotope trace method.The main contributions of our works can be summarized as follows:(1)The temporal and spatial variation characteristicsand pollution source of main pollutants COD,NH3-N,TN and TP ofFenghe river basin were analyzed by collecting data and simultaneous monitoring water quality and quantity of Fenghe river basin,and used the method of organic pollution index method(A value)to evaluate the present conditions of the river water quality.The results showed the parabolic trend of river organic pollution index values A from 2001 to 2011,shows that there is a considerable effect on the management of the river in recent years.(2)The conclusion of water pollutioncharacteristics analysisof Fenghe river basin is:the water pollution of the river basin came from two parts,point and non-point source,both of the ratio of the pollution load was about 50%.Surface runoff livestock breeding,agricultural irrigation,pesticide and chemical fertilizer are the key factors of the non-point source pollution of Fenghe river basin.(3)The characteristics of long series run off and non-point source monitoring analysis of Fenghe river showed that the value of non-point source pollution(NSP)load ratio of chemical oxygen demand(COD)and ammonia nitrogen present a fluctuant change.The NSP load ratio of COD is between 36.00%-64.04%in the total pollution load,the NSP load ratio of ammonia nitrogen is between 25.30%-97.81%in the total pollution load,the NSP load ratio of total nitrogen is between 12.84%-54.45%and the NSP load ratio of total phosphorus is between 21.63%-69.38%in the total pollution load.Non-point source pollution load is influenced by rainfall,surface runoff,agricultural activities,and other comprehensive factors.(4)The analysis of the different pollution sources of ammonia nitrogen and nitre-nitrogen isotope composition in Fenghe river basin was explored and appliedwiththe nitrogen isotope trace method to The ?15N value(average value is aboutl4.5‰)of ammonia nitrogen of untreated sewage in rural areas is much higher than other types of wastewater.There is not a big difference of the ?15N value(average value is about 3.‰)of ammonia nitrogen of the school,paper mill and industry wastewater,and this value is also lower than the agricultural ?15N value.In the dry season,the nitrate pollution of upstream is lower than downstream.In the wet season,about 70%of ammonia nitrogen pollution is derived from the treated and concentrated domestic wastewater and agricultural non-point source pollution.(5)The structure of Fenghe river basin water pollution controlling system is aim at the basin water pollution characteristic and according to "prevention first,adjust measures to local conditions,comprehensive treatment".To the point source pollution control,we should adopt the control mode " cut down the source item,comprehensive utilization and end treatment".To the non-point source pollution control,we should combine each link of the "source" and "collection",focus on the control and management of the "source",and use the different control technology and management measure to control the non-point source pollution. |
PDF Full Text Request