Abstract

Food wastewater contains abundant nutrition substances causing high biological load on the environment. Inorganic and organic synthetic high-polymer flocculants have been most commonly used because of their flocculating efficiency and low cost. Natural organic flocculants possess a certain synthetic advantage. To investigate the optimal flocculant for food wastewater treatment, effects of five organic and chemical flocculants, being Chitosan (CTS), Polyaluminum sulfate (PAS), Polyaluminium chloride (PAC), Polyaluminum ferric silicate (PSAF), Polyacrylamide (PAM) and their pair composite flocculants by stirring have been studied. Under the condition of 300 rpm for 30 min by magnetic stirring apparatus, the optimal dosages of PSAF, CTS, PAC, PAM and PAS were 3.30, 2.19, 5.69, 6.56, and 3.30%, respectively. Therefore, effect of CTS was optimal because of its 87.24% maximal absorbance reduction. CTS demonstrates biodegradability and antibacterial activity, and the hydrophilicity introduced by the addition of polar groups is able to develop secondary interactions (–OH and –NH₂ groups involved in H bonds with other polymers), which results in its excellent flocculant property. The optimal proportions of two components in composite flocculant A (CTS-PSAF), B (PAC-PAM), C (P SAF-PAC), D (PAS-PAM), E (CTS-PAS), F (CTS-PAM) were respectively determined as 0.53, 0.87, 0.46, 0.40, 1.33, and 1.67. Correspondingly, the optimal stirring speeds of every composite flocculant were 20, 20, 125, 125, 160, and 20 rpm. Thus, composite flocculant A was optimal due to 42.89% maximal COD_Cr removal efficiency and 51.54% maximal BOD₅ removal efficiency (COD_Cr—chemical oxygen demand determined by potassium dichromate method). The results have presented that CTS and its pair flocculants CTS-PSAF are effective for food wastewater treatment, indicating that CTS-based flocculants exhibit effective pollution removal ability with wide applications.

中文翻译：

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食品废水处理用复合絮凝剂的筛选

摘要

食品废水含有丰富的营养物质，对环境造成高生物负荷。无机和有机合成高分子絮凝剂因其絮凝效率高、成本低而被广泛使用。天然有机絮凝剂具有一定的合成优势。研究用于食品废水处理的最佳絮凝剂，五种有机和化学絮凝剂壳聚糖（CTS）、聚合硫酸铝（PAS）、聚合氯化铝（PAC）、聚合硅酸铁铝（PSAF）、聚丙烯酰胺（PAM）及其配对的效果研究了搅拌复合絮凝剂。在磁力搅拌装置300转/分30分钟的条件下，PSAF、CTS、PAC、PAM和PAS的最佳用量分别为3.30%、2.19%、5.69%、6.56%和3.30%。所以，CTS 的效果是最佳的，因为它的最大吸光度降低了 87.24%。CTS 表现出可生物降解性和抗菌活性，通过添加极性基团引入的亲水性能够产生二次相互作用（-OH 和 -NH_{2 个}基团与其他聚合物形成 H 键），从而使其具有优异的絮凝性能。复合絮凝剂A（CTS-PSAF）、B（PAC-PAM）、C（P SAF-PAC）、D（PAS-PAM）、E（CTS-PAS）、F（CTS-PAM）中两种组分的最佳配比) 分别确定为 0.53、0.87、0.46、0.40、1.33 和 1.67。相应地，每种复合絮凝剂的最佳搅拌速度分别为20、20、125、125、160和20 rpm。因此，复合絮凝剂 A 是最佳的，因为其最大 COD _{Cr去除效率为 42.89%，最大 BOD 5}去除效率为51.54% （COD _Cr——用重铬酸钾法测定的化学需氧量）。结果表明，CTS及其配对絮凝剂CTS-PSAF对食品废水处理有效，表明CTS基絮凝剂具有有效的污染去除能力，应用广泛。