Evaluation of rainwater quality stored in cisterns of concrete plates and polyethylene in a municipality in the semi-arid of the Paraíba State

ABSTRACT An evaluation of rainwater stored in cisterns in the semiarid region of the state of Paraíba is presented in this paper. Water samples from concrete plates cisterns (CPLAs) and polyethylene ones (CPOLs) were collected and analyzed in order to verify whether there are differences between water quality parameters in the two types of cisterns. Statistical tests were applied to detect whether there are differences between the physical and chemical parameters pH, temperature, turbidity, electrical conductivity, total dissolved solids, dissolved oxygen, alkalinity, color, hardness, chloride, ammonia, sulfate, salinity, and nitrate. Analyses of the variability of the parameters and verifications of compliance were also carried out in accordance with the Ministry of Health Consolidation Ordinance 05/2017, which establishes water potability standards. Among the parameters analyzed in the water samples from the CPLAs and CPOLs, those that confirmed the hypothesis of equality of means were chloride, dissolved oxygen, and sulfate. There were higher alkalinity and salinity variability in CPLAs waters in relation to these parameters in CPOLs. Almost all physicochemical parameters were in compliance with the ordinance, and the exception were color, pH, and turbidity.

摘要 本文针对帕拉伊巴州（Paraíba）半干旱地区储存在水窖中的雨水开展了评价研究。本研究采集并分析了混凝土板式水窖（concrete plates cisterns, CPLAs）与聚乙烯材质水窖（polyethylene cisterns, CPOLs）的水样，以探究两类水窖的水质参数是否存在差异。通过统计学检验方法，对pH、温度、浊度、电导率、总溶解固体、溶解氧、碱度、色度、硬度、氯化物、氨氮、硫酸盐、盐度及硝酸盐共14项理化参数的组间差异进行检测。此外，本研究参照巴西卫生部《第05/2017号饮用水水质标准整合政令》，开展了参数变异性分析与水质合规性验证工作。在两类水窖水样的检测参数中，氯化物、溶解氧与硫酸盐的均值无组间显著差异，符合均值相等的原假设。混凝土板式水窖水样的碱度与盐度变异性显著高于聚乙烯材质水窖。绝大多数理化参数均符合该政令要求，仅色度、pH及浊度三项参数不达标。