Efficiency of domestic wastewater treatment plant for agricultural reuse

The increasing demand for water has made the treatment and reuse of wastewater a topic of global importance. This work aims to monitor and evaluate the efficiency of a wastewater treatment plant's (WWTP) physical and biological treatment of wastewater by measuring the reduction of organic matter content of the effluent during the treatment and the disposal of nutrients in the treated residue. The WWTP has been designed to treat 2500 liters of wastewater per day in four compartments: a septic tank, a microalgae tank, an upflow anaerobic filter and wetlands with cultivation of Zantedeschia aethiopica L. A plant efficiency of 90% of organic matter removal was obtained, resulting in a suitable effluent for fertigation, including Na and Ca elements that showed high levels due to the accumulation of organic matter in the upflow anaerobic filter and wetlands. The WWTP removes nitrogen and phosphorus by the action of microalgae and macrophytes used in the process. The final effluent includes important agricultural elements such as nitrogen, phosphorus, calcium and potassium and, together with the load of organic matter and salts, meets the determination of NBR 13,969/1997 (Standard of the Brazilian Technical Standards Association) for reuse in agriculture, but periodic monitoring of soil salinity is necessary.

随着全球水资源需求持续攀升，污水处理与回用已成为备受关注的全球性议题。本研究旨在通过监测污水处理过程中出水有机物含量的削减情况，以及处理后副产物中营养物质的处置状态，对某污水处理厂（Wastewater Treatment Plant, WWTP）的物理-生物联合污水处理效率开展评估。该污水处理厂设计日处理污水量为2500升，共设置四个处理单元：化粪池、微藻池、上流式厌氧过滤器，以及种植马蹄莲（Zantedeschia aethiopica L.）的人工湿地。研究结果显示，该厂有机物去除率可达90%，产出的出水可用于水肥灌溉；但由于上流式厌氧过滤器与人工湿地内有机物的累积，出水中钠（Na）与钙（Ca）元素含量偏高。该污水处理厂依托工艺中使用的微藻与大型水生植物，实现了对氮、磷的去除。最终出水含有氮、磷、钙、钾等重要农业营养元素，结合其携带的有机物与盐分总量，其水质符合巴西技术标准协会制定的NBR 13,969/1997农业回用规范，但仍需定期对土壤盐度进行监测。