SBR工艺强化反硝化除磷及控制参数

采用SBR反应器,通过在厌氧—好氧运行模式(Ⅰ)中介入缺氧段,即厌氧—好氧—缺氧—好氧运行模式(Ⅱ),缺氧与好氧条件下磷的吸收量的百分比值由28.2%升高至68.3%,实现了反硝化同步除磷、脱氮.系统稳定运行了90个周期,ρ(COD)、ρ(PO₄^3--P)、ρ(TN)平均去除率分别为92.0%、98.0%、81.5%.通过间歇实验发现,ρ(NO₂^--N)=30mg/L时,NO₂^--N对反硝化吸磷并无影响,并且能作为电子受体,与NO₃^--N相比,反硝化吸磷速率更快.实验对pH值、E_ORP进行在线检测发现,厌氧阶段E_ORP曲线上的拐点对应磷的释放终点;好氧阶段ⅠE_ORP和pH值曲线上的拐点则对应着硝化终点;缺氧阶段pH值的拐点对应反硝化终点;好氧阶段ⅡE_CRP和pH值的拐点分别对应COD降解和吸磷终点.因此,pH值、E_ORP能作为实时控制参数,来提高脱氮、除磷效率.

Controlling Parameters in SBR With Enhanced Anoxic Phosphate Uptake

Simultaneous biological phosphorus and nitrogen removal by enhanced anoxic phosphate uptake was investigated in an anaerobic-aerobic-anoxic-aerobic sequencing batch reactor(modelⅡ).The ratio of the anoxic phosphate uptake to the aerobic phosphate uptake capacity increased from 28.2 % to 68.3 % by insert an anoxic phase in an anaerobic-aerobic SBR(modelⅠ).The modelⅡSBR system showed stable phospho- rus and nitrogen removal performance.Average removal efficiencies ofρ(COD),ρ(PO_4~(3-)-P),andρ(TN) were 92.0%,98.0%,and 81.5%,respectively.Through batch experiment,It was found thatρ(NO_2~--N) (up to 30 mg/L)was not detrimental to the anoxic phosphate uptake and could serve as an electron acceptor likeρ(NO_3~-N).In fact,the phosphate uptake rate was even faster in the presence ofρ(NO_2~--N)as an elec- tron acceptor compared to the presence ofρ(NO_3~--N).It was found that on-line sensor values of pH and E_(ORP) were somehow related with the dynamic behaviors of nutrient concentrations(ρ(COD),ρ(NH_4~+-N),ρ(NO_3~--N),andρ(PO_4~(3-)-P)) in the SBR.The inflexion of E_(ORP) profile corresponding to the end of phos- phorus released in anaerobic phase;the inflexion of E_(ORP) and pH profiles corresponding to the end of nitrifica- tion in aerobic phaseⅠ;the inflexion of E_(ORP) and pH profiles corresponding to the end of denitrification in anoxic phase;the inflexion of E_(ORP) and pH profiles corresponding to the end ofρ(COD)exhaust and phos- phorus uptake in aerobic phaseⅡ.These pH and E_(ORP) profile characteristic point could be used as real-time control parameters to adjust the duration of each operational phase in the modelⅡSBR,thus could enhance the nitrogen and phosphorus removal efficiency.