高硬度废水处理生化池中泥-灰旋流分离实验

Hydrocyclone separation of activated sludge and inorganic ash in the biological tank treating high hardness wastewater

针对高硬度废水生化处理过程中生成的无机灰分导致污泥活性降低和沉降性差等问题,采用旋流分离方法实现污泥原位脱灰以改善废水综合处理效能。通过离线和在线实验,探究了污泥与无机灰分的结合形式、泥灰混合物旋流分离效率以及旋流处理对高硬度废水生化处理效率的影响。结果表明,6组不同Ca^(2+)浓度的来水经过150 d生化实验,生化池污泥有机质占比从进水Ca^(2+)浓度为0 mg·L^(-1)时的0.75降至Ca^(2+)浓度为2 400 mg·L^(-1)时的0.39,生化系统COD和氨氮去除率也相应降低11%和60%;原子力显微镜测试结果表明,来水含钙条件下生化池污泥表面因无机灰分附着导致其粗糙度从无钙来水下的20.5 nm增至38.2 nm,且活性污泥与无机灰分间的非稳态结合可通过离心等物理法实现分离;来水Ca^(2+)浓度为800 mg·L^(-1)时,泥灰混合液经过最佳结构旋流器10次循环分离,其有机质占比从0.17升高至0.37;依托120 m^(3)·h^(-1)煤制氢废水处理SBR进行旋流脱灰侧线实验,经过3个月连续运行,改造生化池污泥有机质占比较对比样从0.21提升至0.45,且出水平均COD和氨氮分别降低17.1 mg·L^(-1)和14.3 mg·L^(-1)。活性污泥在线旋流分离调理可为高硬度废水生化处理提标改造提供参考。

The generated inorganic ash in biological reactor treating high hardness wastewater decreased the activity and settleability of activated sludge. Hydrocyclone application was expected to in-situ separate the inorganic ash from the activated sludge and increase its biological treatment efficiency. The attachment pattern and separation efficiency between inorganic ash and activated sludge were investigated by offline and online experiments, as well as the effect of inorganic ash removal on the biological treatment efficiency of simulated high hardness wastewater. The results showed that the organics ratio decreased from 0.75 in SBR reactor without calcium ion to 0.39 with influent calcium ion concentration of 2 400 mg·L^(-1)after 150 d continuous biological treatment of 6 groups of influent with different Ca^(2+)concentrations, COD and NH;-N removal efficiencies also decreased by 11% and 60%, respectively. The atomic force microscope(AFM) images illustrated that the generated inorganic ash increased the surface roughness of activated sludge from 20.5 nm for Ca^(2+)-free influent to 38.2 nm for Ca^(2+)-containing influent. The surface-attached inorganic ash can be removed from the activated sludge by centrifuge. The mixture of inorganic ash and activated sludge in SBR with influent calcium ion concentration of 800 mg·L^(-1)was circularly separated for 10 times by hydrocyclone with the optimum structure, and the organics ratio in SBR increased from 0.17 to 0.37. The side-flow hydrocyclone separation experiments were conducted for 120 m^(3)·h^(-1) SBR in a coal-to-hydrogen gasification wastewater treatment plant, three months running caused the increase of the organics ratio from 0.21 in control SBR to 0.45 in modified SBR, the effluent COD and NH;-N decreased by 17.1 mg·L^(-1)and 14.3 mg·L^(-1), respectively. The new approach of online hydrocyclone separation conditioning provides a reference for the upgrade of the biological treatment efficiency of high hardness wastewater.