Experimental Study On Nitrogen And Phosphorus Removal Of AO Process Synchronization

In recent years, water shortage and water pollution problems increased prominence of the public’s environmental awareness is gradually increased. The eutropHication pHenomenon caused due to excess emissions of nitrogen, pHospHorus and directly led to the thinking of the people on the issue of environmental protection. Worldwide, new effluent standards for nitrogen and pHospHorus content With increasingly stringent requirements. This requires that the water pollution control and governance sewage treatment technology to develop high-efficiency low-power the biological wastewater simultaneous nitrogen and pHospHorus removal technology research has gradually become a hot research field of water treatment.In this experiment, anaerobic-aerobic (AO) for the treatment of city sewage activated sludge, denitrification and P-removal processes of AO synchronization. A systematic study of the factors of operation conditions of the process and a variety of effects, to achieve the best operation condition of simultaneous nitrogen and pHospHorus removal is determined under the condition of test, the influence of summarizing control parameters of AO process simultaneous nitrogen and pHospHorus removal, and explore the treatment mechanism.The results showed that:the AO process system, water C:N:P ratio of47:6:1, the control DO is0.5～0.8mg/L, HRT is9～11h, internal reflux ratio of about1.5, SRT controlled at about16d, PH7-7.5control, the temperature is around25℃. AO system to achieve simultaneous nitrification and denitrification and denitrifying pHospHorus removal of ammonia, TN removal best removal rates were98.70%,92.68%,95.84%. Unit sludge denitrification capacity (QTN、VTN) reaches its maximum, respectively, to reach14.3310-3mg/(L·mgMLVSS),1.43×10-3mg/(L·mgMLVSS·h); Meanwhile, unit sludge addition ability of pHospHorus (QTP、VTP) strong performance at this time were1.5510-3mg/(L·mgMLVSS),0.15×10-3mg/(L·mgMLVSS· h).Optimal running conditions, there are plans to change the DO, COD, HRT, SRT, PH, temperature control parameters, various operating parameters of nitrogen and pHospHorus removal system disparate impact:①. Aeration zone DO concentration0.9～2.0mg/L range of changes, the system would undermine the effect of denitrification, denitrification ability. DO concentration in the aeration zone0.3～0.5mg/L range changes cause the system nitrification insufficient to reduce the effect of nitrogen and pHospHorus removal.②. When the C:N:P ratio of67:6:1, the ammonia effluent higher, TN removal rate, prone to secondary pHospHorus release; when the C:N:P ratio of21:6:1, the system denitrification effect is not obvious, and pHospHorus removal rate.③. When HRT at8h～16h of changes, ammonia and TN removal rate increases, up to the limit95%; HRT at7h～9h,11～17h less than the effect of pHospHorus within the range of9h～11h within the good results95.84%.④. When the pH value of6.3to7.0, the system effluent nitrate, ammonia content is high, denitrification and pHospHorus removal systems are suppressed. When the pH is7to8.5, the system of nitrogen and pHospHorus removal ability, simultaneous nitrogen and pHospHorus removal with the increase of PH changed for the better.⑤.SRT in12d～22d, with the sludge age increases, TN removal efficiency increased, while TP removal efficiency decreased.⑥. At10℃～18℃case temperature sludge settling properties deteriorate, the system’s ability to decrease nitrification, denitrification is limited. While reducing the amount of pHospHorus release, PAOs, DPB pHospHorus removal capacity is limited.