Análise da qualidade da água do riacho das Piabas para o reúso agrícola.

Abstract

In developing countries, due to deficient sanitation, untreated wastewaters are discharged irregularly into surface water bodies and drainage channels. In these countries, agricultural reuse is generally not regulated and is practiced in an indirect and unplanned manner, downstream of clandestine sewage contributions, exposing both population and the environment to risks associated with untreated wastewater. This study aimed to analyze the water quality of Riacho das Piabas, located in the city of Campina Grande, state of Paraíba, for agricultural reuse, for subsidize studies on the management of urban drainage water reuse. Physicochemical and microbiological indicators of samples of drainage water from six points along the stream were monitored. Results were evaluated according to national standards and international guidelines for agricultural reuse. The self-purification capacity along the Riacho das Piabas was also evaluated using the QUAL-UFMG model, and the risks associated with health, safety and the environment in its drainage area based on the Failure Mode and Effects Analysis methodology. It was found that the studied waters are not suitable for agricultural reuse, requiring either treatment or dilution to reduce organic load, nutrients, salinity and faecal indicators, even in rural areas, downstream, where their quality is better, due to self-cleaning, compared to their characteristics, typically of sanitary sewage, in upstream urban areas. Risk assessment indicated that points located in urban areas are critical and, therefore, need short-term interventions, and the risk of pollution by organic matter should be prioritized.