细微泥沙对污水生化处理系统的影响及其归趋特性  

Effect of fine sediment on wastewater treatment biochemical system and its fate characteristics

作　　者：吉芳英[1] 何小玲[1] 何莉[1] 周卫威[1] 

机构地区：[1]重庆大学三峡库区生态环境教育部重点实验室,重庆400045

出　　处：《环境工程学报》2014年第3期801-806,共6页Chinese Journal of Environmental Engineering

基　　金：国家水体污染控制与治理重大科技专项(2013ZX07314-001-002)

摘　　要：大量运行数据表明,取消初沉池的污水厂泥沙淤积严重、污泥MLVSS/MLSS比值低,严重影响了污水厂的正常运行和功能提升。以取消初沉池后不能被有效去除的粒径≤200μm的细微泥沙为研究对象,通过对比实验的方法研究了不同粒径细微泥沙对污水生化处理系统的影响及其归趋特性。运行结果表明,当在污水中分别投加粒径为26、73、106、165和210μm的细微泥沙300 mg/L时,运行40 d后,生化系统活性污泥的MLVSS/MLSS比值将从启动初期的0.84分别下降至0.27、0.29、0.59、0.65和0.73,且随MLVSS/MLSS比值的下降,混合液SVI值也明显降低,反应器底部淤积泥沙量分别相当于进水泥沙总量的31.0%、47.4%、75.2%、75.9%和91.6%,表明小粒径颗粒更容易被活性污泥包裹,引起污泥MLVSS/MLSS下降,大粒径颗粒更容易淤积在反应器底部;由于泥沙淤积致使颗粒粒径越大,通过排放剩余污泥除砂的量越少,按照粒径递增的顺序,通过剩余污泥外排的除砂量分别相当于进水泥沙总量的44.5%、31.3%、20.3%、20.5%和7.2%。A lot of operational data show that cancelling primary settling tank causes serious sediment deposition and low MLVSS/MLSS ratio in wastewater treatment plant,which would seriously affect the normal operation and functional promotion of wastewater treatment plant. We took fine sediment as the research object which particle size was less than 200 μm and couldn＇t be effectively removed without primary settling tank. The effect of different sized fine sediment on wastewater treatment biochemical system and its fate characteristics were analyzed by comparison test. The running results showed that 300 mg/L addition of fine sediment which particle sizes were 26,73,106,165 and 210 μm,respectively,the MLVSS/MLSS ratios of biochemical system activated sludge decreased from 0. 84 to 0. 27,0. 29,0. 59,0. 65,0. 73,respectively after 40 days. With the decrease of MLVSS/MLSS ratio,the SVI values fell significantly. And the amount of sediment deposited in the bottom of reactor were equivalent to 31. 0%,47. 4%,75. 2%,75. 9%,91. 6% of the total sediment entering the biochemical system respectively. It indicated that the smaller sediments were more likely to be wrapped in activated sludge,which causing the sludge MLVSS/MLSS ratio decline,and the larger particles accumulated in the bottom of reactor easily. Due to sedimentation deposition,the greater the particle size was,the smaller amount of fine sediment was discharged by excess sludge. With the ascending order of particle size,the efflux amount of sediment in excess sludge were equivalent to 44. 5%,31. 3%,20. 3%,20. 5%,7. 2% of the total influent sediment respectively.

关 键 词：污水处理 细微泥沙 活性污泥 MLVSS MLSS比值 泥沙淤积 

分 类 号：X703.1[环境科学与工程—环境工程]