Avaliação da poluição difusa no sistema de macrodrenagem de Campina Grande-PB.

Abstract

The growth of cities together with lack of investment in urban infrastructure has caused the deterioration of the environment and natural resources. In this context it is usual to find in several Brazilian cities illegal connections of sewage of rainwater drainage systems, thus compromising the water quality of the same. Campina Grande (PB), is located in this group of cities that has been affected by this problem. In this way, the work aims to evaluate the diffuse pollution in your drainage system, represented by the Prado canal. For both, were determined physical and chemical indicators (temperature, electrical conductivity, pH, turbidity, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, ammoniacal nitrogen, kjeldahl nitrogen, total phosphorus, total hardness, calcium and sodium) and microbiological (thermotolerant coliforms) water samples collected in eight points distributed along the canal. In addition, a study performed for the self-depuration capacity of the canal in front of the whole release of wastewater. Subsequently, it was examined whether the feasibility of using drainage waters in agriculture, fish farming, industry and irrigation of green areas. In the end, been employed the methodology of risk assessment Failure Mode and Effect Analysis (FMEA) in order to estimate the risk to health and safety to which the riverside population to the canal are exposed. Through laboratory testing it was found that the drainage waters of the canal of the Prado show typical concentrations of sewage ranging from weak, medium and strong depending on the location of point. It was found that 68% of the canal is under conditions of anaerobiosis. In general, the drainage waters of the Prado canal can be used for irrigation only species tolerant to salinity. For fish farming and irrigation of green areas this is recommended only if it is used together with a better water quality, or, for the latter, in case by disinfection treatment due to high levels of thermotolerant coliforms. To industry, only the water from specific points along the canal, also limited the restrictions. From the risk assessment found that the risk of pollution from wastewater release is responsible for almost 50% of the total system risk, followed by flood related risks, irregular buildings, proliferation of arthropods and rodents, unplanned reuse and sewage reflux. It was verified that the points six and seven have obtained the greatest individual risks sum, which suggests adoption of preventive and corrective measures in the short term in the above points.