Removal of THM precursors from a high-alkaline surface water by enhanced coagulation and behaviour of THMFP toxicity on D. magna
Removal of THM precursors from a high-alkaline surface water by enhanced coagulation and behaviour of THMFP toxicity on D. magna
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DOI：
10.1016/j.desal.2004.10.020
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发表时间：
2005-06
期刊：
影响因子：
9.9
通讯作者：
L. Rizzo;V. Belgiorno;M. Gallo;S. Meriç
中科院分区：
文献类型：
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作者：
L. Rizzo;V. Belgiorno;M. Gallo;S. Meriç
本研究评估了聚合氯化铝（PAC）与硫酸铝（明矾）和氯化铁（FeCl 3）相比在去除两个样品的THM前体和降低THM形成潜力方面的有效性（S1和S2）来自低TOC（<3 mg/l）、高碱度（180 mgCaCO 3/l）和pH（8.0）的地表水资源，以符合意大利对TTHM的严格限制（30 μg/l）。所使用的混凝剂的有效性进行了评估，通过测量的浊度，TOC，在254 nm波长（UV 254）的UV吸光度，和总三卤甲烷形成的潜力（TTHMFP），以及通过监测其毒性行为使用标准化的，可靠的，和节省时间的生物测试（大型蚤急性固定化测试）在原料，凝固，氯化样品。PAC 1是去除两种样品（S1和S2）浊度的最有效的混凝剂;然而，它不能像FeCl 3和明矾那样有效地减少NOM。对于S2，PAC对于溴仿去除的选择性比FeCl 3更高。所用的凝结剂剂量都不能将TTHM降低到所需的限度，即使是高剂量（80 mg/l）也不行。毒性试验结果显示不同的行为，由于凝血剂的类型和剂量。强化混凝处理可使氯化原水的毒性得到一定程度的降低。这项研究表明，NOM表征的必要性，以优化混凝过程，以及将其与先进的前/后处理技术，以获得安全的水。
This study evaluates the effectiveness of polyaluminium chloride (PACl) compared to aluminium sulphate (alum) and ferric chloride (FeCl3) to remove THM precursors and reduce THM formation potential of two samples (S1 and S2) from a surface water resource with low TOC (<3mg/l), high alkalinity (180 mgCaCO3/l) and pH (8.0), to comply with stringent Italian limits for TTHMs (30 μg/l). The effectiveness of the coagulants used was evaluated by measurements of turbidity, TOC, UV absorbance at 254 nm wavelength (UV254), and total trihalomethanes formation potential (TTHMFP), as well as by monitoring their toxicity behaviour using a standardized, reliable, and time-saving biotest (Daphnia magna acute immobilization test) in raw, coagulated, and chlorinated samples. PACl was the most effective coagulant to remove turbidity for both samples (S1 and S2); however, it did not reduce NOM as effectively as FeCl3and alum. For S2, PACl was more selective for bromoform removal than FeCl3. None of the coagulant doses applied could reduce TTHMs to the required limits, not even high doses (80 mg/l). Toxicity test results displayed different behaviour due to coagulant type and dose. The toxicity of raw chlorinated water could be reduced by a slightly but significant degree by enchanced coagulation. This study showed the necessity of NOM characterization to optimize the coagulation process as well as integrating it with an advanced pre-/post-treatment technology to obtain safe water.