| In accordance with the document "Decision on Building An Ecological Shandong" issued by the Shandong Provincial Party Committee and government,the local Environmental Protection Bureau required changle Chengdong Sewage Treatment Plant to further improve the discharge standard of water quality on the basis of the original sewage treatment quality,carry out the upgrading of the existing facilities,and require the chemical oxygen demand(COD)of the discharged water after the tendering is less than 40 mg/L.Bidding scheme and treatment effect constitute the research content of this paper.In this paper,in order to meet the technical transformation of wastewater in-depth treatment process,a technical scheme of deep coagulation+ozonation-contact activated carbon filtration as the main COD removal method was adopted,and the technical details were studied.The influence of influencing factors on removal performance was tested by chemical coagulation test and field dosing test,and the effect of deep coagulation was measured.Small and pilot results show that when the polyaluminium chloride,M180 coagulants and polysilicic acid ferric sulfate and the four kinds of flocculants such as polyacrylamide drug dosing quantity is 75-100 mg/L,meets the design goal of effluent COD removal rate increased by 20%,that change the flocculant types and optimize the flocculant dosing quantity can improve the effect of coagulation sedimentation,meet the set requirements.Based on the original ozonation system,an activated carbon filter was added to test the COD removal effect of the ozonation and activated carbon combination process.The test results showed that when the ozonation concentration was 30mg/L,the ozonation and activated carbon combination process could ensure the effluent stable COD below 40mg/L.The online monitoring results of the on-site deep treatment process show that the enhanced coagulation+ ozonation+post-activated carbon filtration process can meet the COD depth requirements of the on-site discharge water and ensure the stability of the effluent index.The COD removal rate of each process section in the depth treatment was 40%in the coagulation sedimentation tank,25%in the enhanced coagulation and in the continuous sand filter tank,30%in the ozone oxidation tank and carbon tank and disinfection.The COD removal rate of each process section after the depth treatment was in series could reach 69%.The calculation results of project investment cost and unit operating cost show that the unit operating cost of deep treatment of some ozone addition is much higher than other costs,indicating that the control of ozone oxidation index is more critical.Through the above research and experiments,the deep treatment process scheme of Changle Chengdong sewage treatment Plant was determined,and the COD<40 mg/L discharge requirements after the upgrading of Changle Chengdong sewage treatment plant were realized,which had good popularization and application value. |
