| The eutrophication of water body and blue-green algae water bloom caused by eutrophication are important environmental problems for many lakes and reservoirs in China.In order to release the impact of algae water bloom on water environment,the blue-green algae was extracted from the lake,and then the water mixed with algae separated by coagulation or air floataion was directly discharged into the river,the rest concentrated algae mud was treated and utilized after dehydration.If the extracted algae was rot,substance from the algae cell will be released to water,which contain a lot of pollutants such as organic substance,nitrogen,phosphorus,microcystins and so on.The wastewater seriously damage water environment and threat water supply security if it was directly discharged into river.It is the first time to select anoxic and aerobic aerated biological filter combined with ultraviolet ray cataltic oxidation and chemical methods to deal with the wastewater by making experiments in this paper.Studying the influencing factors of the process and optimizing some relative parameters to obtain the best treatment effect.To explore the possibility of using the process in treating wastewater,which could make some references for algae station.The main conclusion are as follows:(1)The AO-BAF had a effective work on wastewater after separation,the COD,NH4+-N,TN,TP,microcystins concentration of wastewater changed from 250.0mg/L,389.77mg/L,399.96mg/L,2.58mg/L,1.69ug/L to 47.01mg/L,92.99mg/L,300.61mg/L,2.30mg/L,1.69ug/L,the removal for COD is 81.20%,NH4+-N 76.14%,TN 24.84%,TP 10.85%,Microcystins 6.50%after treatment under the work condition that the water flow is 2L/h,HRT of anoxic,aerobic biological filter is 1.91h and 5.73h,reflux ratio is 100%,the chroma and smell of wastewater was greatly improved,the COD concetration of wastewater after treatment can reach the first grade A of Discharge standard of pollutants for municipal waste-water treatment plant(GB 18918-2002).The removal for nitrogen was not satisfied,which need to optimize some relative parameters to improve the treatment.(2)The treatment efficiency of AO-BAF was improved after optimization.with the increasing of C/N ratio,the removal of system for COD and TN was raised to 98.62%,50.13%,effluent COD and TN concentration were 44.19mg/L and 199.48mg/L,the removal for NH4+-N were descended to 51.17%,effluent NH4+-N concentration were 190.31mg/L;Under the common working condition of HRT and C/N ratio,the removal of system caused by reflux ratio had little effect on COD,but the removal of system for NH4+-N and TN were improved,the removal for NH4+-N and TN were raised to 61.57%,57.55%,effluent NH4+-N and TN concentration were 149.78mg/L and 169.78 mg/L;Under the common working condition of C/N ratio and reflux ratio,the removal of system caused by HRT had little effect on COD,but the removal of system for NH4+-N and TN were further improved,the removal for NH4+-N and TN were raised to 69.28%,67.36%,effluent NH4+-N and TN concentration were 119.75mg/L and 130.54mg/L,resulting in the removal of system for Nitrogen was obviously improved.(3)The optimum parameters of anoxic and aerobic biological filter are as follws:the water flow is 1L/h,HRT of anoxic,aerobic biological filter is 3.82h and 11.46h,C/N is 8,reflux ratio is 200%.The removal of system for CODNH4+-N and TN were 98.73%,69.28%,67.36%,the COD,NH4+-N,TN concentration of wastewater after treatment were 40.62mg/L,119.75 mg/L,130.54 mg/L,which under the best working condition.The COD concentration of wastewater after treatment can reach the first grade A of Discharge standard of pollutants for municipal waste-water treatment plant(GB 18918-2002),the NH4+-N and TN concentration of waste water after treatment were highly removed.(4)The ultraviolet ray cataltic oxidation could remove microcystins effectively,the microcystins concentration of wastewater were gradually descended with the increasing of lighting time and consumption of electricity,the microcystins concentration of wastewater after oxidation changed from 1.58?g/L to 0.35?g/L in the end,the removal percentage were 76.58%.In addition,the radius of lighting had little effect on removal,the consumption of electricity in 11.58×10-2kW·h·m-3 are better suggested,which had a better removal efficiency.(5)The addition of PAC and FeCl3 had a effective removal on TP after coagulation,the removal percentage could reach 83.04%and 84.78%,the TP concentration of wastewater after coagulation changed from 2.30 mg/L to 0.39mg/L and 0.35mg/L,which can reach the first grade A of Discharge standard of pollutants for municipal waste-water treatment plant(GB 18918-2002).The dosage of PAC and FeCl3 are better suggested in 60mg/L,which had a better removal efficiency,and FeCl3 is a bit better than PAC. |
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