RESUMO
RESUMO A remoção da cobertura vegetal e a impermeabilização de grandes áreas somadas à ineficiência dos serviços básicos de saneamento, contribuem para o aumento das cargas poluidoras pontuais e difusas que são transportadas superficialmente pelas águas pluviais, causando impactos negativos ao sistema de drenagem. Como o despejo ilegal de efluentes domésticos em redes de drenagem é uma realidade observada em todo o país, principalmente no meio urbano, hoje, a maior preocupação dos gestores e estudiosos é voltada às fontes pontuais de poluição e, apesar da importância, as fontes difusas têm recebido pouca atenção. Este trabalho objetivou modelar, utilizando o programa Storm Water Management Model (SWMM), a qualidade das águas pluviais a partir da avaliação do acúmulo de poluentes na superfície do solo em períodos secos e da lavagem durante eventos de precipitação na Bacia Hidrográfica Riacho do Prado, inserida no perímetro urbano da cidade de Campina Grande, Paraíba. Oito pontos no canal de drenagem foram monitorados, analisando-se as variáveis demanda bioquímica de oxigênio (DBO), demanda química de oxigênio (DQO) e fósforo total (FT), além da determinação da vazão. Os resultados obtidos nas simulações do comportamento dos poluentes em escala temporal para o evento medido do dia 08 de junho de 2018 foram condizentes com os valores observados nas análises laboratoriais, confirmando a eficiência dos resultados para as outras simulações realizadas. Os dias antecedentes sem chuva e a intensidade da precipitação se mostraram importantes na análise da carga poluente.
ABSTRACT Removal of vegetation cover and the expansion of impermeable land, together with the inefficiency of basic sanitation services, contribute to the increase of point and diffuse pollutant loads drained by rainwater, causing negative impacts at drainage system. As the illegal discharging of domestic sewage in drainage canals is a reality observed throughout the country, especially in urban areas, today the main concern of managers and researchers is directed to the point sources of pollution and, despite the importance, diffuse sources have received little attention. This work aims to model the rainwater quality using the Storm Water Management Model (SWMM) from the evaluation of buildup pollutants on the soil surface in dry periods and the washoff during precipitation events in the Riacho do Prado watershed located in the urban area of Campina Grande, Paraíba. Eight points were monitored at the drainage canal, in which the variables BOD5, COD, and total phosphorus were analyzed, in addition to flow determination. The results obtained on the simulations of behavior of pollutants in time scale for the actual event of 06/08/2018 were in agreement with the values observed at laboratory analyses, confirming the efficiency of results for the other simulations. The previous days without rain and the intensity of precipitation were important in the analysis of the pollutant load.
RESUMO
The purpose of this work was to carry out a risk assessment of human health and safety associated with the dangers encountered in an urban basin located in Campina Grande, the State of Paraíba, northeastern Brazil, called the Prado Basin, through the method of failure mode and effects analysis (FMEA). As a subsidy to the study, laboratory analyses of drainage water were performed at eight points distributed along the Prado Canal, a canal of the study area, to verify its quality and subsequent influence on the population's health. It was verified that the risk of effluent discharge pollution stood out from the others, accounting for almost 50% of the total risk of the system. In the risk ranges, this was classified in points six and seven as critical and in points two, three, and four as high risk, which implies the urgency of adopting measures that minimize or resolve this risk at these points. In general, it was found that points six and seven totaled the highest sum of individual risks, suggesting the adoption of short-term preventive and corrective measures in the aforementioned points.
