微生物超量吸收实现生物脱氮

研究了SBR在不同pH值条件下处理模拟城市生活污水中的脱氮效果.结果表明,在曝气时间为4 h,沉淀静置时间为4h,进水COD浓度为250~300 mg.L-1,进水NH4+-N浓度30~40 mg.L-1时,R2(pH为8.0±0.2)出水氨氮浓度降到0~1 mg.L-1同时有大量的硝态氮生成,出水中硝态氮(NO3--N+NO2--N)的浓度基本在8~10 mg.L-1之间,TIN(TIN=NH4+-N+NO3--N+NO2--N)的去除率在70%左右.R1(pH为7.0±0.2)出水氨氮浓度降到0~5 mg.L-1,而硝态氮浓度在整个过程中基本保持不变且含量极低(1~2 mg.L-1),污泥中总氮含量较高且4 h好氧阶段呈先下降后上升的趋势,典型周期好氧开始时污泥中总氮含量为214 mg.g-1,好氧1 h时含量为210 mg.g-1,好氧结束时含量为215 mg.g-1,水相中TIN的去除率达到85%以上.说明在本研究特殊的工艺条件下,SBR能实现较高的生物脱氮效果,但氮的去除并不是通过传统的硝化反硝化途径实现,而是通过排除微生物超量吸收的富氮污泥来实现.

Biological Nitrogen Removal with Excess Nitrogen Uptake by Microorganisms

The performance of nitrogen removal with sequencing batch reactors were investigated in different pH conditions using simulated municipal wastewater. The experimental results showed that ammonium and nitrate as well as nitrite in R2 (pH controlled at 8.0 ± 0.2) were 0-1 mg·L~(1-) and 8-10 mg·L~(1-) respectively, while ammonium and nitrate as well as nitrite in Rl (pH controlled at 7.0 ± 0.2) were 0-5 mg·L~(1-) and 1-2 mg·L~(1-) respectively under the operational process of 4-hour aeration→4-hour settle/idle phase, which indicated the removal rates of TIN (TIN = NH_4~+ -N + N0_3~+ -N + NO_2~+ -N) in Rl and R2 were above 85% and about 70% respectively, when the COD and ammonium concentrations in influent were 250-300 mg· L~(-1) ,30-40 mg· L~(-1), respectively . Total nitrogen in sludge was at a high level and increased in the aeration after decreasing in the first hour aeration, the content of total nitrogen in sludge was 214 mg·g ~(-1) at the beginning of aerobic phase, 210 mg·g~(-1) in the first aeration and 215 mg·g~(-1) at the end. The researches indicated that high efficiency of nitrogen removal could be obtained in sequencing batch reactor and nitrogen removal in this study was not realized by traditional nitrification/denitrification approach but by the discharge of rich-nitrogen sludge.