State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, Institute of Biofilm Technology, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, PR China; College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China.
State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, Institute of Biofilm Technology, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, PR China.
Chemosphere. 2018 Nov;211:1054-1064. doi: 10.1016/j.chemosphere.2018.08.030. Epub 2018 Aug 11.
Efficient removal of bio-refractory dissolved organic matter (DOM) and colorants is essential for discharging or reusing the distillery wastewater. An important part of recalcitrant DOM still exists in the effluent of regular coagulation though the ferric coagulant has been found to be effective in decoloration. The present work adopted powdered activated carbon (PAC) as ballasting agent to achieve robust separation effect and efficiency of bio-refractory DOM from the bio-chemically treated cassava distillery wastewater (BTDWW). More than 90% of DOC could be removed at the PAC and Fe(III)-coagulant dosage of 1.40 g/L and 0.84 g/L as Fe when the BTDWW was neutral. PAC should be dosed before coagulant in order to mix well with the DOM in the BTDWW. The analyses of DOM in effluent reveal that PAC facilitated the removal of lignin breakdown products which could not be well eliminated by regular coagulation; the removal of DOM with MW < 5 kDa was mostly enhanced. The characteristics of flocs demonstrate that PAC reinforced the interaction between Fe(III) species and DOM by providing more reaction sites. The sedimentation could be completed within the initial 5 min, and the highest settling velocity was almost 8 times higher than that of the only Fe(III)-involved flocs. The large size and favorable robustness of PAC-involved flocs enabled decent sedimentation even though their stretched structure might not be desirable in regular coagulation. The PAC-ballasted coagulation is recommended as tertiary treatment of BTDWW considering its high efficiency and sound economic feasibility.
有效去除生物难降解溶解性有机物（DOM）和着色剂对于排放或再利用酿酒废水至关重要。尽管铁系混凝剂已被证明在脱色方面非常有效，但仍有一部分重要的难生物降解 DOM 存在于常规混凝的出水 中。本工作采用粉末活性炭（PAC）作为加重剂，从生物化学处理木薯酒精废水（BTDWW）中实现生物难降解 DOM 的强 烈分离效果和效率。当 BTDWW 呈中性时，PAC 和 Fe(III)混凝剂的投加量分别为 1.40 g/L 和 0.84 g/L 作为 Fe 时，DOC 的去除率超过 90%。PAC 应在混凝剂之前投加，以便与 BTDWW 中的 DOM 充分混合。出水 DOM 的分析表明，PAC 促进了木质素分解产物的去除，而常规混凝剂对此难以有效去除；MW < 5 kDa 的 DOM 去除率也得到了较大提升。絮体特性表明，PAC 通过提供更多的反应位点，增强了 Fe(III)物种和 DOM 之间的相互作用。沉淀可以在最初的 5 分钟内完成，最高沉淀速度几乎是仅含 Fe(III)絮体的 8 倍。PAC 参与的絮体尺寸较大，稳定性较好，即使其伸展结构在常规混凝中可能不理想，也能实现良好的沉淀。考虑到 PAC 加重混凝法具有高效和良好的经济可行性，建议将其作为 BTDWW 的三级处理方法。
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