Research On Current Situtation And Control Strategy Of Dongguan River

The development of urbanization aroused a series of eco-environmental problems. And the problems of urban rivers such as water quality worsening,self-purification losing and ecological environment breaking appeared most soriously as more and more pollutants were discharged into the urban rivers.Dongguan river,established in 1970,was the biggest comprehensive drainage and irrigation project combing freshwater diversion,flood control,flood drainage and ship transport in Dongguan city.Since the 1980s,with the rapid development of industrialization and urbanization the invasion of a large quantity wastewater led to serious deterioration of water environment of the river.This study focused on the integrate control of the Dongguan canal.Long-term monitoring of the water quality was put into practice and its pollution status was evaluated in detail.Based on the critical problems causing the contamination a suit of proposals were put forward with supporting measures.The water quality monitoring results showed that until now the quality has reached the surface water environmentâ…¤level standard(GB3838-2002) and was moderate contamination.The indexes exceeding the limited standardâ…¢included dissolved oxygen(DO),permanganate index,chemical oxygen demand(COD),biological oxygen demand(BOD),ammonia nitrogen,total phosphorous and petroleum.The main pollutants were organic,phosphorus and nitride,and their pollution-sharing rates were 68.20%and 19.21%,individually,while metal,inorganic and bacteria were few. For organic,the ratio of petroleum was highest.In view of water quality monitoring section,the water quality worsened gradually from upstream to downstream.The water quality in low-flow period was worse than that in average and high flow period.The pollutants mainly come from sewage and industry wastewaters,landfill leachate,agriculture and greening wastewaters,and extraneous sources contamination. Based on the above pollution sources a control strategy including pollutant intercepting,sediment cleaning,water source activiting and dike treating was brought out.The control focused on intercepting pollutants and aimed to recover self-purification capacity of water body by eliminating sediment,replacing wastewater,building ecological embankment,ecological repairing,etc.