Study On The Purification Technology And Effect Evaluation In A Demonstration Scale For The Landscape River

With the rapid development of economy in the urban area,many rivers are polluted in different degrees in cities,and the water environmental capacity trend to weaken.Restoring the ecosystem is very necessary to every city.The landscape river is the primary water body in the urban moderate polluted slow-flow water bodies.This paper was supported by the project of "Major National Science and Technology"(Grand NO.2011ZX07301-002),the high-efficient technique for nitrogen and phosphorus removal from the moderate polluted slow-flow water bodies were mainly analyzed in this paper.Based on the experimental study and the character of the typical moderate polluted slow-flow water bodies,the landscape rivers in Changzhou city,Jiangsu Province were selected.Some conclusions were summarized from the indoor and demonstration project test as following:(1)The study proposes a high-efficient technique for nitrogen and phosphorus removal to treat the moderate polluted municipal slow-flow water bodies.The TN removal efficiency can reach over 80%in the mixotrophic denitrification and it has obvious advantages at the cost of treatment.Under the optimal conditions,the maximum removal efficiency of TP can finally reach over 85%in the moderate polluted slow-flow water bodies.The total iron concentration is lower than the 0.3mg/L,the limit standard of the "Drinking Water Health Standards"(GB5749-2006).(2)After the demonstration project operated,the ecosystem were been recovered gradually in 3 months.The concentration of TN was reduced from 14.1mg/L to 3.4mg/L and ammonia nitrogen was reduced from 8.0mg/L to 1.1mg/L,COD was dropped from 63.0mg/L to 26.2mg/L,TP was from 1.2mg/L to 0.25 mg/L.In addition to the TN,the other water quality index of the landscape rivers are basically reached the standard of "Surface Water Quality Standards"(GB3838-2002)class ?.The landscape river had been in a state of eutrophication which led by the high concentration of TN and TP.(3)Totally 57 species,8 phylums of phytoplankton were identifed in the riverway of urban landscape,among which Chlorophyta and Bacillariophyta were the dominant species,the density and species composition of phytoplankton were varietied with the season.13 species of zooplankton were identifed,and there was no significant difference between the two landscape rivers.There were two species common in the two landscape rivers.Totally 23 species of rotifers were identified in the riverway of urban landscape and the primary species are the Brachionus calyciflorus and Polyarthra trigla.Negative correlations were found between the density of rotifers and the trophic level index of pollutants.Highly significant negative correlations were found between the biomass of rotifer and the trophic level index of TN.Also,negative correlations were found between the biomass of rotifer and the trophic level index of NH3-N and the TSI(?).