Suitability of the Decentralised Wastewater Treatment effluent for agricultural use: Decision Support System approach

The study aimed to (i) assess the suitability of AF effluent irrigation water quality for different crops (maize, cabbage and lettuce), soils (coarse sand, sandy loam and clay) in four agro-ecological regions of South Africa, with special focus on impacts on microbial contamination, crop quality, soil quality and environmental pollution, and (iii) provide recommendations for optimizing soil quality, crop yield and human health in DEWATS effluent irrigated soils across agro-ecological regions of South Africa. The South African Water Quality guideline decision support system was parameterized using the characterization data from the Anaerobic Filter (AF) effluent and simulated for a period of 45 years. The model generated the effects of AF effluent on the soil (soil profile salinity, soil permeability, oxidisable carbon loading and trace element accumulation), yield and crop quality in maize, lettuce and cabbage (root zone effects, leaf scorching when wetted, contribution to NPK removal and microbial contamination) and effects on irrigation equipment (corrosion or scaling of irrigation equipment and clogging of drippers).

本研究旨在（一）评估南非四个农业生态区域中，厌氧滤池（AF）排放水对玉米、卷心菜和生菜等不同作物以及粗沙、沙壤土和粘土等不同土壤的灌溉水质适宜性，特别关注其对微生物污染、作物品质、土壤品质和环境污染的影响；（三）针对南非农业生态区域中厌氧湿地污水处理系统（DEWATS）排放水灌溉土壤，提供优化土壤品质、作物产量和人类健康的建议。本研究利用厌氧滤池排放水的特征数据，对南非水质指南决策支持系统进行了参数化，并对其进行了为期45年的模拟。模型生成了厌氧滤池排放水对土壤（土壤剖面盐分、土壤渗透性、可氧化碳含量和微量元素积累）、产量和作物品质（根系效应、湿润时的叶片烧焦、对NPK的去除贡献和微生物污染）以及灌溉设备（灌溉设备的腐蚀或结垢以及滴灌器的堵塞）的影响。