Department of Civil and Environmental Engineering, Lehigh University, 13 E. Packer Avenue, Bethlehem, PA 18015, USA.
J Water Health. 2010 Mar;8(1):60-70. doi: 10.2166/wh.2009.210.
Over 1.1 billion people in the world lack access to improved drinking water. Diarrhoeal and other waterborne diseases cause an estimated 1.87 million deaths per year. The Safe Water System (SWS) is a household water treatment intervention that reduces diarrhoeal disease incidence among users in developing countries. Turbid waters pose a particular challenge to implementation of SWS programmes; although research shows that a 3.75 mg l(-1) sodium hypochlorite dose effectively treats turbid waters, users sometimes object to the strong chlorine taste and prefer to drink water that is more aesthetically pleasing. This study investigated the efficacy of two locally available chemical water treatments-alum and Moringa oleifera flocculation-to reduce turbidity and chlorine demand at turbidities of 10, 30, 70, 100 and 300 NTU. Both treatments effectively reduced turbidity (alum flocculation 23.0-91.4%; moringa flocculation 14.2-96.2%). Alum flocculation effectively reduced chlorine demand compared with controls at 30, 70, 100 and 300 NTU (p=0.01-0.06). Moringa flocculation increased chlorine demand to the point where adequate free chlorine residual was not maintained for 24 hours after treatment. Alum pretreatment is recommended in waters>or=30 NTU for optimum water disinfection. Moringa flocculation is not recommended before chlorination.
全球有超过 11 亿人无法获得改善后的饮用水。腹泻和其他水传播疾病每年导致约 187 万人死亡。安全水系统（SWS）是一种家庭水处理干预措施，可降低发展中国家用户的腹泻病发病率。混浊水对 SWS 计划的实施构成了特殊挑战；尽管研究表明，3.75mg/L 的次氯酸钠剂量可有效处理混浊水，但用户有时会反对强烈的氯味，并更喜欢饮用更美观的水。本研究调查了两种当地可用的化学水处理方法-明矾和辣木絮凝-在 10、30、70、100 和 300 NTU 的浊度下降低浊度和氯需求的效果。两种处理方法均能有效降低浊度（明矾絮凝 23.0-91.4%；辣木絮凝 14.2-96.2%）。与对照组相比，在 30、70、100 和 300 NTU 时，明矾絮凝可有效降低氯需求（p=0.01-0.06）。辣木絮凝会增加氯需求，以致处理后 24 小时内无法维持足够的游离氯残留。建议在浊度>或=30 NTU 的水中进行明矾预处理，以实现最佳水消毒。不建议在氯化处理前进行辣木絮凝。
