改型生物砂滤池防治滤料堵塞的实验研究

Prevention of Blocking in Modified Biological Sand Filter

构筑初滤池并添加灰岩颗粒作为滤料,研究改型生物砂滤池的防堵效果。结果表明,初滤池对污水中悬浮物去除率可达到75%以上,能有效缓解由难降解物质引起的滤料板结与堵塞;在实验初期加强复氧、降低进水有机污染负荷的情况下,含50%灰岩的滤池出水pH值平均为7.58,水力负荷平均为2.05 m/d,稳定运行时间从不含灰岩时的20 d提高到56 d以上,对氨氮、总磷的去除率分别为53.49%及43.32%;在正常布水情况下,含30%灰岩的滤池出水pH值平均为7.84,水力负荷平均为1.75 m/d,稳定运行时间为30 d左右,对氨氮、总磷的去除率分别为16.18%及42.96%;气反冲洗能快速有效地解决滤池堵塞问题,反冲洗后第二天水力负荷即恢复到1.53 m/d,最高水力负荷达到2.55 m/d,但实际应用中结构复杂,能耗高。

Prevention of blocking in modified biological sand filter,which is pretreated by primary filter and constructed by mixed limestone and river sand was investigated.Experimental results showed that more than 75% of suspended solid were removed by primary filter to prevent from material hardening and blocking caused by non-degradable substance.By enhancing re-aeration and reducing organic pollution load,average pH of the effluent was buffered to 7.58 in the filter containing 50% limestone which can run more than 56 d at an average hydraulic loading rate of 2.05 m/d compared to 20d with no limestone,with removal rate of ammonia nitrogen and total phosphorus of 53.49% and 43.32% in the filter respectively.In the condition of normal water distribution,average pH of the effluent was buffered to 7.84 in the filter containing 30% limestone which can run about 30d at an average hydraulic loading rate of 1.75 m/d,with removal rate of ammonia nitrogen and total phosphorus in the filter 16.18% and 42.96% respectively.The blocked filter can be recovered faster and more effectively by air backwashing.Hydraulic loading rate was 1.53 m/d in the second day after backwashing and the maximum hydraulic loading rate can reach 2.55 m/d.However it would consume more energy and the structure would be more complex in practical application.