粉煤灰絮凝除藻配方优化及相关毒理学评价

Study on the Optimization of Fly Ash Flocculant in Its Algal Removal Efficiency and Its Toxicological Evaluation

[目的]改善絮凝剂配方,对絮凝剂进行回收利用以降低成本,同时对絮凝剂在水体中应用的安全性进行毒性评价。[方法]在实验室已有研究基础上改进絮凝剂配方,用低浓度HC l代替高浓度HC l改性粉煤灰,与磁矿粉复配去除水藻,分析水体中藻细胞及氮、磷去除率;对絮凝剂回收方法进行探讨;最后用秀丽隐杆线虫和大鼠进行毒理学评价。[结果]3 mol/LHC l改性粉煤灰絮凝剂除藻效果显著,投加量为0.375 g/L时总氮、总磷及浊度去除率分别为41.7%、92.3%、97.4%。采用湿法回收絮体,回收后充当磁矿粉可重复利用5次以上,且氮、磷的去除率无明显下降。秀丽隐杆线虫在经絮凝剂处理后的藻水中受试48 h后存活率达95%;大鼠急性经口毒理试验的半数致死量(LD50)>15 000 mg/kg(b.wt)。[结论]絮凝剂配方优化以及絮凝剂回用均降低了除藻成本;生物活体毒理试验显示该技术安全。

[Objective] The paper aimed to optimize the formula of the flocculants and recycle the flocculant to reduce the cost.Moreover,the application of the flocculant in water had been toxicologically evaluated.[Method] Based on the results that have been made in our laboratory,the formula of the flocculants were optimized that the fly ash were modified by hydrochloric acid with low rather than high concentration.After combining with magnetic powders,the flocculants were used to treat the algal water.The removal rate of algal cells and the total nitrogen and phosphorus were analyzed.Additionally,discussions concerning the methods of recycling the flocculants and its efficiency had been presented.[Result] Results had shown that 3 mol/L hydrochloric acid-modified fly ash had the best algal-removal efficiency.When the dosing was 0.375 g/L,the removal rate of total nitrogen,total phosphorus and the turbidity was 41.7%,92.3% and 97.4% respectively.The flocs were wet recovered more than 5 times to use directly as magnetic powders,and the flocculation effect had no significant decrease.Compared to the algal solution,flocculant-treated water did not reduce the survival efficiency of Caenorhabditis elegans.LD50 value of rats acute oral toxicity was larger than 15 000 mg/kg（b.wt）.[Conclusion] The formula of the fly ash flocculants was optimized and the cost had been significantly reduced.Vivo experiments had shown that this technique is environmental-friendly and ecologically safe.