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.