微气泡曝气生物膜反应器同步硝化反硝化研究

同步硝化反硝化(SND)是废水处理中的新型生物脱氮工艺,和传统生物脱氮工艺相比具有显著的应用优势.本研究采用微气泡曝气固定床生物膜反应器,研究了SND过程中污染物去除效果并检测了生物膜功能菌群的变化情况.结果表明,在微气泡曝气固定床生物膜反应器内可以实现同步硝化反硝化,通过提高进水COD负荷和C∶N比,降低溶解氧(DO)浓度,同时增加填料床层孔隙率,可以改善SND效果.当进水COD负荷和总氮(TN)负荷为0.86 kg·(m3·d)-1和0.10 kg·(m3·d)-1,且填料床层孔隙率为81%时,COD和TN的去除率分别为97.6%和70.2%,实现了COD和TN的同步高效去除;同时,微气泡曝气对氧传质的强化作用使得氧利用率高达91.8%.此外,生物膜活性和硝化及反硝化功能菌群的变化,与反应器COD、氨氮和TN去除能力的变化基本一致.

Simultaneous Nitrification and Denitrification in a Microbubble-aerated Biofilm Reactor

Simultaneous nitrification and denitrification (SND) is a new wastewater treatment process for biological nitrogen removal, which shows some significant advantages compared with conventional biological nitrogen removal processes. The SND process in a fixed bed biofilm reactor with microbubble aeration was investigated in this study. The removal efficiencies of COD and nitrogen were determined under different operational conditions and the functional bacterial populations for nitrogen removal in the biofilm were detected. The results showed that efficient SND process could be achieved in the biofilm reactor with microbubble aeration. The SND could be improved at lower dissolved oxygen (DO) concentration and larger porosity of packing bed when the COD loading rate and C/N ratio were increased. The removal efficiencies of COD and total nitrogen (TN) were 97.6% and 70.2%, respectively, at a COD loading rate of 0.86 kg·(m³·d)^-1, a TN loading rate of 0.10kg·(m³·d)^-1, and a packing bed porosity of 81%, indicating the simultaneous efficient removal of COD and TN. Under these conditions, the oxygen utilization efficiency reached as high as 91.8% due to the enhanced oxygen mass transfer by microbubble aeration. In addition, the biofilm activity and the abundance of nitrifiers and denitrifiers were consistent with the removal capacity of COD, ammonia and TN under different operational conditions.