Study On Water Quality Improvement Engineering Technology Of Typical Urban Black And Odorous River

With the industrialization and modernization of human society,the black odor phenomenon of urban rivers has been intensified.However,the black odor of urban rivers was not formed overnight,and the black odor of urban rivers was not caused by a single factor.It is impossible to solve the problem of black and odor of urban rivers and improve the water quality only by single engineering measures,which requires overall planning and systematic management of the whole river basin.This paper takes Tangjiashangou watershed as the research object,the main causes of river pollution were systematic analyzed based on field survey,data collection,investigation of river pollution status.Combined with other river water quality improvement project case studies,specific engineering measures to improve the water quality of Tangjiashangou were proposed.The effect of implementing engineering measures was also evaluated according to the water quality monitoring data.Pollution control and interception is the basis and premise of other engineering measures,and it is also the most effective and direct engineering measures to improve river water quality.Constructed wetland and ecological slope protection can effectively remove COD,BOD5,NH3-N,TN and TP in the initial rainwater,and have a good effect on water purification.Constructed wetland and ecological revetment could reduce COD concentration by 3.99mg/L and 3.02mg/L,NH3-N concentration by 2.27mg/L and 2.86mg/L,and TP concentration by 0.51mg/L and 0.41mg/L,respectively.The combination of multi-stage(subsurface flow + surface flow)constructed wetland and flood skimming ditch not only ensured water safety,but also used plants,microorganisms and fillers to purify water,taking into account water environment and water ecology.After the external and internal pollution being effectively controlled,the effect of ecological restoration engineering measures and water supply will be better.Both ecological floating island and ecological landscape engineering can purify water quality,clear water supply can increase water mobility,microporous aeration can improve the dissolved oxygen level of the river,and increase the water mobility in the river;the effect of clear water supply engineering measures is more obvious.Ecological floating island,microporous aeration and fresh water supply could reduce COD concentration by 3.31mg/L,2.91mg/L and 4.56mg/L,NH3-N concentration by 2.31mg/L,3.33mg/L and 6.87mg/L,and TP concentration by0.35mg/L,0.43mg/L and 0.77mg/L,respectively.According to the water quality monitoring results in 2019,after the external and internal pollution has been effectively controlled,the integrated application of technologies such as constructed wetland,ecological slope protection,ecological floating island,microporous aeration,clean water supply and ecological landscape had been implemented in Tangjiashan gully to remove the existing pollution and the external pollution that had not been completely controlled.The water quality of Tangjiashan gully can reach DO > 5mg/L,NH3-N < 1mg/L and ORP > 100 m V,after integrated application,the water environment quality of Tangjiashan gully was significantly improved.