污泥回流比对双污泥BCR反硝化除磷效果的影响

Influence of Sludge Recycle Ratio on Removal of Nitrogen and Phosphorous in Two-Sludge BCR Denitrifying Phosphorus Removal Process

以模拟华南地区的城镇污水为研究对象,开展了污泥回流比对连续流双污泥生物澄清反应器(BCR)反硝化除磷的影响研究.结果表明:超越污泥和回流污泥的回流比分别控制为0.6、0.4和0.2时,BCR工艺对COD_(Cr)去除率的均值分别为89.98%、89.48%和82.38%,出水COD_(Cr)质量浓度平均为20.94、21.67、37.66 mg/L;而总氮的去除率均值则分别为79.94%、80.58%和65.47%,出水总氮质量浓度平均为5.72、5.75、10.85 mg/L;总磷去除率的均值分别为88.81%、91.64%和77.06%,出水总磷质量浓度均值为0.76、0.59、1.62 mg/L,新工艺改善了传统双污泥连续流工艺出水NH_4^+-N质量浓度偏高的缺陷.工艺在超越污泥回流比和回流污泥回流比均是0.4时处理效果最佳.由于好氧硝化池与中沉池合建,好氧硝化池中的NO_3^--N与中沉池中的DPB接触,发生反硝化吸磷的反应,使部分总磷在好氧硝化池中被去除.

The influence of different sludge ratios from middle sedimentation tank to anoxic reactor （exceeding sludge ratio） and from final sedimentation tank to anaerobic reactor （recycled sludge ratio） on denitrifying phosphorus removal in two-sludge BCR denitrifying phosphorus removal process was investigated using simulated domestic wastewater.Results showed that when the ratios of two kinds of sludge are 0.6, 0.4 and 0.2, the resulting average CODCr removal rates are 89.98%, 89.48% and 82.38%, total nitrogen removal rates are 79.94%, 80.58% and 65.47%, and phosphorus removal rates are 88.81%, 91.64% and 77.06%, respectively.The effluent COD concentrations are 20.94, 21.67 and 37.66 mg/L, total nitrogen concentrations are 5.72, 5.75 and 10.85 mg/L, and phosphorus concentrations are 0.76, 0.59 and 1.62 mg/L, respectively.Compared to two-sludge A2N process, the problem of high ammonia nitrogen has been improved.When the ratios of two kinds of sludge are 0.4, two-sludge BCR denitrifying phosphorus removal process has the best pollutant removal efficiency.Since the aeration tank and sedimentation tank are integrated, denitrifying dephosphatation with nitrate as electron acceptor occurred under anoxic condition due to contribution of denitrifying phosphorus removal bacteria.