| According to statistics,218 cities were screened out black-odor water bodies in out of 295 prefecture-level cities and above,accounting for 73.9%of the total.And only 77 cities didn't.In order to curb the continued deterioration of the water,the State Council issued the "Water pollution control action plan"(referred to as "Ten Water").By 2030,the fine proportion of water quality will have reached over 75%in the seven major river basins in the whole country,and the black and smelly water bodies will have been eliminated.Tongling Green Lake has the attributes of "River and Lake".Due to the confluence of rain and sewage,Sewage are directly discharged into Green Lake with waste?sludge?oil?etc.It cause serious water pollution.This paper takes Tongling Lake as the research object.From the point of view of ecological restoration of urban rivers and lakes,Tongling Green Lake is a project such as interception of sewage,dredging,and ecological purification,and evaluates the effects of the project,which provides a reference for the restoration and treatment of urban polluted water under similar conditions.The main results of the system has the following four aspects.(1)Based on the related theories of ecology and engineering,taking the integration of bio-ecological restoration technology as a means,through the project implementation and effect monitoring,the ecological restoration engineering technical system is preliminarily constructed in line with the pollution characteristics of Lake Green's water body.The system by the ecological purification as the core,the comprehensive use of various repair methods to coordinate governance.(2)In view of the external pollution from the upper reaches of the city,a variety of physical engineering methods are employed,including mechanical blocking,pollution interception and efficient sewage treatment.In view of the internal pollution of the river and lake itself,the ecological system adapted to the aquatic plants and aquatic animals was constructed.The lake environment characteristics,to create a water ecological balance system to adapt to the landscape.These systems and technology can effectively remove the waste water in 80%of the SS and oil and more than 50%of the COD and BOD,reduce NH3-N,TP.The main lake lake CODcr concentration index.The lowest content reached 1.39 mg/L,0.189 mg/L and 8.5 mg/L,respectively.At the same time,the dissolved oxygen in water was improved,the highest content of oxygen was up to 6.36 mg/L.In addition,the removal efficiency of pollutants in the same site showed a rule of TP>NH3-N>TN>permanganate,and the effect of pollutant removal was significant.(3)Using a variety of water quality evaluation methods to evaluate water quality monitoring,the results showed that the single factor exponent method showed that TP and CODcr have aeached Surface Class ? water standard.The Nemerow index method shows that the main lake surface belongs to mild pollution.The comprehensive pollution index method shows that the comprehensive pollution index of the main lake surface is stable at about 1.7.The overall situation is that the quality of water changed from the original inferior ? category to the surface water category ?.In addition,such indicators as TP?CODcr?and NH3-N in some regions can meet the Class ? standard for surface water.(4)The practical results show that the ecological restoration technology of has multiple effects.First,it can significantly reduce the concentration of pollutants flowing into Green Lake upstream of the city,improve the water quality of urban rivers and lakes,and purify water quality.And then,it enriched the biodiversity and enhanced the stability of the ecosystem by aquatic and living plant cultivation and microbiological deployment.In addition,the implementation of Green Lake estoration project has prevented the large-scale reconstruction of the old city and has obvious social and economic benefits. |
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