The Research And Design On Updating The Technology At The Wastewater Treatment Plant Two In Dalian Development Zone

One of the most effective ways to solve the water environment pollution and ease the watershortage contradiction is the urban wastewater treatment and recycling. In order to improve therecycling rate of urban wastewater, Discharge Standards of The Urban Wastewater TreatmentPlant （GB18918-2002） is promulgated to improve the discharge standards. The WastewaterTreatment Plant Two （WWTP II） in Dalian development zone was built in1997, which isadapted to the anaerobic/good oxygen of activated sludge process, reaching level2dischargestandards. According to new release of Liaoning province local standards DB21/1627-2008"integrated wastewater discharge standard" in July1, the WWTP II in Dalian development zoneupgrades to effluent complying with the DB21/1627-20081A discharge standard. The papercombines the existing treatment processes and water quality in the WWTP II in Daliandevelopment zone, to conduct research on treatment process. Through the comparison betweenthe technique and economy, the paper aims to certain out upgrading technology solution, and tooptimize the design parameters and process design.It’s planning to design the reconstruction project scale with the existing wastewatertreatment plant design scale, namely80000m3/d. According to the water quality monitoringdata between2006and2009, it’s confirmed to establish design Influent quality for SS=300mg/L, BOD₅=350mg/L, CODcr=700mg/L, TN=80mg/L, TP=9mg/L. it expects toachieve level A of "urban wastewater treatment plant discharge standards". i.e.: SS=10mg/L,BOD₅=10mg/L, CODcr=50mg/L, TN=15mg/L, NH3-N=5mg/L, TP=0.5mg/L.According to influent quality, combined with the original processing technology, through thecomparison of the three sets of technology solutions, the paper is determined the overall schemeof the biological treatment system is level2biological treatment with phosphorus removalfunction, completely nitrification and denitrification. Biological treatment system modified theA²/O synchronized biology eliminating the phosphorus denitrification, the newly biological poolis built to improve A²/O phosphorus removal denitrification, it is planning to build A²/Ophosphorus removal denitrification biological pool in two groups which is to improve twoexisting primary settling tanks and four A/O phosphorus removal biological pools. Depthprocessing is adapted to the treatment process of high density traps+V type ponds; thedisinfection is used ultraviolet disinfection process. It explains the processing of the designparameters optimization structures and design calculation and makes a benefit analysis for theeconomy and engineeringIn sum, improved A²/O biological phosphorus removal denitrification process+high densitysettling tanks+v-type filter+ultraviolet disinfection process can make effluent water qualityreach level A of the urban sewage treatment plant discharge standards （GB18918-2002）.