Study On Application Of Disinfection In Urban Sewage Treatment Plants

With the development of the social economy, the intensification of the waterpollution and the increase of the human requirements for water environment quality,the security issue about wastewater reclamation and reuse has caused widespreadconcern in the world. The State Environmental Protection Administration and StateAdministration of Quality Supervision, Inspection and Quarantine promulgated theurban sewage treatment plant emission standards （GB18918-2002） on December24,2002, is the first time to classify the pathogenic microorganisms fecal coliformcolumns as the basic control indicators, and must disinfect urban sewage.This article do research on the MSBR crafts water leakage in a sewage factory,emission requirements are first level A and first level B effluent fecal coliform.experiment are majorly producibility and pre-production, combined with small test,Mainly do experimental study on sanitizing effect, influencing factors, Bio-securityand chemical safety, disinfection costs. studied disinfection technology of separate UV,sodium hypochlorite, chlorine dioxide, combination of UV and sodium hypochloriteseparately.The results showed that UV disinfection under the circumstances of waterturbidity is less than5.0NTU and UV intensity is greater than83%（detection valueby UV intensity detector in the UV disinfection equipment （%））have achieved goodresults. after36mJ/cm²UV disinfection, the fecal coliform counts are less than10⁴/L,The effluent can achieve first level B,after51mJ/cm²UV disinfection,the fecalcoliform counts are less than10³/L The effluent can achieve first level A.When emission requirements of effluent fecal coliform meeted first level A andfirst level B, the quantity of sodium hypochlorite was2mg/L and4mg/L separately,disinfection costs were0.0208yuan/m³and0.0407yuan/m³. moreover thedisinfection byproducts increased along with the test dosage increases,when under theconditions of effective chloric from1mg/L increased to5mg/L,THMs increased from0.09mg/L to0.174mg/L, trichchloroacetic increased from0.0058mg/L to0.074mg/L, ClO₂^-increased from0.29mg/L to0.78mg/L,but the dichloroacetic acidproduction did not change significantly, basically in between0.004mg/L to0.007mg/L，ClO₃^-production did not change significantly, basically in between0.30mg/Lto0.35mg/LThe research of chlorine dioxide disinfection technology found that chlorinedioxide dosage were separately2.28mg/L and1.52mg/L when meat emissionrequirements of effluent fecal coliform meted first level A and first level B,thedisinfection operating costs were separately0.0328yuan/m³and0.0226yuan/m³.The combination of disinfection test of UV/HOCl showed that effect of UV firstwould be better than the HOCl first; because the former would produce synergism，the latter wouldn’t.