Wastewater Treatment Characteristics Of Attached-suspended Growth System In Sequencing Batch Reactor

Using polymer porous particulate as carriers, some wastewater treatment characteristics of suspended-attached system in sequencing batch reactor were studied in this thesis. COD and NH₄⁺-N removal rates were compared between suspended-attached system and activated sludge system. Good removal rate of suspended-attached system(or bio-film system) in sequencing batch reactor(BSBR) was attainted during treating wastewater at influent COD concentration of 1200mg/L when adopting 3 hours aeration and 1 hour settling. The results indicated that the removal rates of COD and NH₄⁺-N were higher than 90% and 70% respectively. Main factors affecting COD removal rate were orderly aeration volume, aeration and settling duration. As to NH₄⁺-N, main factors were orderly aeration duration, aeration volume and settling duration. Dissolved oxygen(DO) showed more effects on NH₄⁺-N removal than COD removal. High removal efficiency in BSBR was attained even if suspended sludge (SS) concentration was relatively low. In another word, the BSBR showed good adaptability in low microbiological concentration. The BSBR recovered to good condition quickly after impact load, which told us its nice anti-impacting-load ability. The removal efficiency of different modes with aeration, mixture and setting combination were researched. Best treatment efficiency had been observed when adopting the mode with 1 hour mixture, following 3 hours aeration, and then 1 hour setting. On researching the influence of C:N ratio to the treatment efficiency, we found when COD/NH₄⁺-N remained in the range of 10²5, COD and NH₄⁺-N had preferable removal rates. The optimal pH range values are 8⁹ and 7⁹ respectively during the processes of nitrification and denitrification. BSBR could reach to 91.8% mean COD removal rate, which showed the same behavior with SBR on COD removal. The mean COD removal rate of the latter could reach to 89.6%.A conclusion that BSBR was more superior than SBR on removing dissolved organic content could be attained from the small difference of mean COD removal rate.