Impact of the use of rural domestic sewage treated in UASB reactor and polishing ponds on soil properties

Abstract

The treatment and reuse of domestic effluent is an important strategy for increasing local water availability, reusing nutrients for plant development and increasing productivity, reducing environmental pollution and promoting health. In this work, the impact of irrigation on the soil with wastewater from the treatment system implemented in the Dom José Rodrigues Training Center - CFDJR, belonging to the Regional Institute of Small Appropriate Agriculture - IRPAA, composed of a UASB reactor (Upflow Anaerobic Sludge Blanket) and polishing ponds. Post-treatment water and soil samples were collected at depths of 0 - 20, 20 - 40 and 40 - 60 cm, to assess the chemical and biological/sanitary impacts on the soil caused by the use of wastewater. It was observed that during the period from June 2019 to November 30, 2021, 303.24 m³ of wastewater were reused at the experiment site. From the analysis of the water carried out at the exit of the polishing ponds, average treatment efficiencies of around 93% were verified for Escherichia coli. (E. Coli.), 96% for Thermotolerant Coliforms and absence of helminth eggs. From the chemical analyzes of the soil, contents of total nitrogen, phosphorus, potassium, calcium, magnesium and sodium of 31.4; 67.5; 43.3; 0.9; 1.40 and 54.4 mg L-1, respectively, considerable values ??for agriculture. Thus, the sanitary sewage system studied proved to be efficient in the treatment of rural domestic wastewater and the generated effluent used as a product for fertigation did not cause environmental pollution to the soil.