Institute of Hydrodynamics of the Czech Academy of Sciences, Pod Patankou 5, 166 12 Prague 6, Czech Republic.
Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic.
J Environ Sci (China). 2019 May;79:25-34. doi: 10.1016/j.jes.2018.09.024. Epub 2018 Oct 5.
The removal of algal organic matter (AOM) is a growing concern for the water treatment industry worldwide. The current study investigates coagulation of non-proteinaceous AOM (AOM after protein separation), which has been minimally explored compared with proteinaceous fractions. Jar tests with either aluminum sulphate (alum) or polyaluminium chloride (PACl) were performed at doses of 0.2-3.0 mg Al per 1 mg of dissolved organic carbon in the pH range 3.0-10.5. Additionally, non-proteinaceous matter was characterized in terms of charge, molecular weight and carbohydrate content to assess the treatability of its different fractions. Results showed that only up to 25% of non-proteinaceous AOM can be removed by coagulation under optimized conditions. The optimal coagulation pH (6.6-8.0 for alum and 7.5-9.0 for PACl) and low surface charge of the removed fraction indicated that the prevailing coagulation mechanism was adsorption of non-proteinaceous matter onto aluminum hydroxide precipitates. The lowest residual Al concentrations were achieved in very narrow pH ranges, especially in the case of PACl. High-molecular weight saccharide-like organics were amenable to coagulation compared to low-molecular weight (<3 kDa) substances. Their high content in non-proteinaceous matter (about 67%) was the reason for its low removal. Comparison with our previous studies implies that proteinaceous and non-proteinaceous matter is coagulated under different conditions due to the employment of diverse coagulation mechanisms. The study suggests that further research should focus on the removal of low-molecular weight AOM, reluctant to coagulate, with other treatment processes to minimize its detrimental effect on water safety.
藻类有机物（AOM）的去除是全球水处理行业日益关注的问题。本研究调查了非蛋白态 AOM（蛋白质分离后的 AOM）的混凝作用，与蛋白态部分相比，这方面的研究较少。在 pH 值为 3.0-10.5 的范围内，使用硫酸铝（明矾）或聚合氯化铝（PACl）进行了 0.2-3.0mg Al/每 1mg 溶解有机碳的 jar 测试。此外，还从电荷、分子量和碳水化合物含量等方面对非蛋白态物质进行了特征描述，以评估其不同部分的可处理性。结果表明，在优化条件下，只有高达 25%的非蛋白态 AOM 可以通过混凝去除。最佳混凝 pH 值（明矾为 6.6-8.0，PACl 为 7.5-9.0）和去除部分的低表面电荷表明，主要的混凝机制是将非蛋白态物质吸附到氢氧化铝沉淀物上。在非常狭窄的 pH 范围内可以达到最低的残留 Al 浓度，尤其是在 PACl 的情况下。与分子量较低（<3kDa）的物质相比，高分子量类似糖类的有机物更适合混凝。它们在非蛋白态物质中含量较高（约 67%），是去除率低的原因。与我们之前的研究相比，这表明由于采用了不同的混凝机制，蛋白质态和非蛋白质态物质在不同条件下进行混凝。研究表明，应进一步研究其他处理工艺对低分子态 AOM（不易混凝）的去除，以最大程度地减少其对水安全的不利影响。
