Investigation Of Rivers And Study On Pollution Control In Shunde District

River is an important resource and wealth of city and country, which has great value on water supply, drainage, transportation, environment, ecology, sports, and etc. The rivers in Shunde are polluted increasingly seriously and the water environment quality is worse year by year with the rapid economic development of the Pearl River Delta in recent years. The pollution has already worsened our living environment seriously and it is urgent to promote the river remediation work on the base of investigation of river pollution in Shunde.In this paper, rivers can be divided into A, B, and C grade on the base of extensive researches on Shunde Rivers. There are1900rivers in Shunde and the quantity of C grade rivers account for90%. The rivers of grade A and B have lager quantity of flow, faster velocity and better quality, so it is feasible to solve the pollution problem with conventional methods. However, the rivers of grade C are the smallest rivers without attention and are polluted by sewage, agricultural and industrial pollution. The water environmental qualities of them are very poor and it is urgent to establish a set of theories and methods of governing small rivers.1. Theoretical StudyThe rivers of grade C are narrow and have less water and slower flow. They can be treated with different principles and methods according to three different situations:slow water flow, zero water flow and refuse blockage. The main conclusions of theoretical study are as follows:1)The disadvantages of S-P model used for the grade C rivers were proposed(i.e., the quality of the grade C rivers was so poor that the result of DO was negative which was inconsistent with reality) based on the deep analysis of SP model theory. The correction method of SP model was proposed, i.e., the result was zero when thecalculation result was negative.2)Three calculation methods were proposed and established, and they were applicable to the BOD degradation coefficient of sluice river, re-aeration coefficient and photosynthetic oxygen production of a river with garbage-covered, respectively.3)The minimum quantity and minimum flow rate concepts of grade C rivers were proposed based on the case of shorter length and low coefficient of BOD degradation and re-aeration. These two theories were applied to the formulation of water diversion program and degradation and dilution of pollutants program.These theories and methods were important complements to the remediation theory and practice of the Pearl River Delta.2. Application ResearchThe application of these theories and practical achievements of rivers remediation were illuminated that took the formulation of Shunde Beima River remediation plane as an example.Beima River is a representative grade C river in Shunde. The length of it is3427m, the average width is15m, the depth is1.4m and the water velocity is0.1m/s. Beima River is faced with many pollution sources:domestic pollution, industrial pollution and rural non-point source pollution. The quantity of Beima River is inferior to the V degrade and the indexes of ammonia nitrogen, total phosphorus, dissolved oxygen, COD are overproof to varying degrees.The DO and re-aeration capacity of Beima River could far from offset the pollution load of the serious industrial pollution, agricultural pollution, sewage, etc. according to theoretical calculations. Beima River is severe hypoxia and its ability to natural healing disappears. In order to improve the water quality gradually and restore the basic ecological functions, several measures should be taken:reduce the emission of pollutants largely, establish perfect sewage collection pipe network, establish matched sewage treatment facilities and improve the quantity and flow rate ecologically.The mainly remediation programs of Beima River are as follows:1)The adjustment and deeply reform of industrial structure;2)Intensify efforts to the pollution remediation and clean-up of riversides and intensify efforts to the supervision of industrial waste water discharge with standards;3)Establish a perfect sewage collection system;4)Strengthen the management of the livestock breeding industry;5)Transfer water to make the water flow;6)Strengthen the cleanness and management of the river.