Commutative Multi-Influent Wastewater Treatment Process With Five Tanks For Nitrogen And Phosphorus Removal

Commutative multi-influent wastewater treatment processs with five tanks for nitrogen and phosphorus removal, a new developed process, consisted of five biochemical reaction tanks and a settling tank. Compared with conventional activated sludge process, mixed liquor recirculation was omitted and sludge recirculation was decreased. The process was characteristic of continuous influent, cyclic running and integrative design. Six phases constituted a running period. All biochemical reaction tanks experienced anaerobic, anoxic and oxic state in diverse phases. All influent underwent spatio-temporal anaerobic, anoxic and oxic condition also.Operational characters of commutative multi-influent wastewater treatment process with five tanks for nitrogen and phosphorus removal were conducted: Principal phase time and transitional phase time were about 3 hours and 2 hours respectively. Sludge return ratio and Sludge Retention Time were about 30% and 12 days respectively. At the temperature of 15～20 oC Hydraulic Retention Time in biochemical reaction tanks was no less than 12.5 hours. At the temperature of 23～28 oC Hydraulic Retention Time could be cut 2 hours down. At the temperature of 15～20 oC the loads of COD,BOD5,T-N,NH3-N,T-P were about 0.21～0.36 kg/(m3·d), 0.12～0.18kg/(m3·d),0.025～0.048kg/(m3·d),0.032～0.048kg/ (m3·d),0.004～0.006 kg/ (m3·d) respectively. The removal efficientgcy of COD,BOD5, T-N,NH3-N,T-P were about 75%,85%,70%,90%,90% respectively.The quality of effluent can rearch the National Discharge Standard GB18918-2002 of Pollutants for Municipal Wastewater Treatment Plant. The phosphorus content in sludge was about 3.09%.In commutative multi-influent wastewater treatment process with five tanks for nitrogen and phosphorus removal, variational rule of ORP correlated with denitrificaition and phosphorus release. To strengthen denitrificaition and phosphorus release, the needful organic compound in influent should be distributed rationally to denitrificaition and phosphorus release tanks based on the ORP profiles. In the course of denitrificaition and phosphorus release, ORP declined steadily. ORP fluctuated or rised, effects of denitrificaition and phosphorus release were unconspicuous. The system can be operated with the combination of traditional time control and real-time control of ORP and DO. The operational model were conducted:(1)Wastewater should be fed in the tanks of ORP fluctuating and rising or be increased which serviced for denitrificaition or phosphorus release.(2)DO levels of the tanks which were aerobic should be kept above 4mg/L.The species of microorganism were abundant and activated sludge run well. Activated sludge microorganism in all microorganism accounted for 80%. Appearance of hulled protozoa constituted by most Arcella hemisphaerica indicated outstanding nitrification. Total quantity of bacteria was about 7.86×107 Cell/mL. Quantities of nitrobacteria and polyphosphate accumulating organisms were less one order of magnitudes than total quantity of bacteria respectively.