Avaliação da qualidade de água de chuva armazenadas em cisternas de placas na microrregião do alto sertão paraibano.

Abstract

Plate cisterns represent a practical solution to deal with water limitations in the Brazilian semi-arid region. In this research, the municipalities studied are Sousa and São João do Rio do Peixe, where water from 20 cisterns in these municipalities was analyzed. The methodology involved the collection of 20 water samples from cisterns in the two municipalities. The physical-chemical parameters of pH, Turbidity, Ammonia, Nitrite, Alkalinity, Hardness, Color, Phosphorus, Nitrate, Conductivity, Chlorides and Biological were analyzed. Statistical tests were used by comparing means, with tests performed using Excel software, with a 5% significance level (00.5), with the null hypothesis being rejected if the p-value ≤ α. Statistical analysis was performed using Excel software, using a significance level of 5% (α = 0.05). The results indicated that there was greater variability in parameters such as ammonia, nitrate, hardness and conductivity in cistern water compared to September 2023 and April 2024, showing that during the rainy season there is a difference in the composition of the water. It was also observed that outliers occurred, that is, a significant deviation from the general trend of a data set in parameters such as Ammonia and conductivity, which showed points below the minimum values for water collected in September 2023. Alkalinity showed values above the maximum point for the period April 2024. Regarding extreme values, it was possible to observe in the conductivity parameter in the month of September 2023 to April 2024, above the maximum points. The parameters studied presented comparative average results in which Hypothesis H₀ is not rejected, demonstrating that there were no sudden changes between the median values regarding the quality of water collected between the periods. Statistical analyses confirmed correlations between poor maintenance practices and compromised potability parameters, confirmed by bacteriological analysis using the COLILERT test in which 100% of the samples were contaminated by E. coli. It is concluded that slab cisterns play a crucial role in providing water in rural communities, but their effectiveness depends on integrated actions that include community training, infrastructure improvements and continuous monitoring of water quality.