化学生物絮凝工艺的反应机理初探

考察了化学生物絮凝工艺中的Zeta电位、颗粒物粒度分布和溶解性有机物的分子质量分级，并分别与化学强化一级工艺和初沉池进行了对比.研究表明，相同药剂投加量下，化学生物絮凝工艺和化学强化一级工艺的出水Zeta电位值基本相等，化学生物絮凝工艺的回流污泥所携带的化学药剂几乎不影响反应池内颗粒物的稳定状态，其中的生物作用是该工艺对污染物的絮凝效果优于化学强化一级工艺的关键因素.在化学生物絮凝工艺中，投加药剂仅对粒径>10 μm颗粒物和分子质量>6 ku溶解性有机物有较好的去除效果，而生物絮凝作用不但可以促进对大粒径颗粒物和大分子质量溶解性有机物的去除，而且对小粒径颗粒物和小分子质量溶解性有机物也有较好的去除，其出水中粒径>3 μm的颗粒物被完全去除，分子质量为2～6 ku 的溶解性有机物的去除率也高达42.5%.

Analysis on Mechanism of the Chemical-Biological Flocculation Process

Zeta potential, particle size distribution and molecular weight distribution of dissolved TOC were studied to elementarily disclose the mechanism of the chemical-biological flocculation (CBF) process to treat municipal wastewater. Chemically enhanced primary treatment (CEPT) process and primary sedimentation tank process were taken as the parallel-compared wastewater treatment processes. The experimental results show that under the same dosage, Zeta potential of the CBF process effluent is equal to that of the CEPT process, which indicates that flocculant in return sludge does not change the stabilization of particles in CBF reactor, and the biological flocculation is the key reason for CBF is superior to CEPT. In CBF process, good removal results are achieved for particles >10 microm and dissolved TOC with molecular weight >6 ku by chemical dosage, and biological flocculation can not only promote the removal of particles >10 microm and dissolved TOC with molecular weight >6 ku, but also have high capacity to remove small particles and dissolved TOC with small molecular weight, with the results that particles >3 tpm are removed completely and TOC with molecular weight of 2-6 ku are removed by 42.5% .