Abstract
The decentralised wastewater treatment system (DEWATS) is an onsite sanitation technology that can be used in areas away from municipal sewerage networks. The discharge of effluent emanating from DEWATS into water bodies may cause pollution. Agricultural use of the effluent may improve crop yields and quality thereby contributing to food security in low-income communities. There are drawbacks to the agricultural use of treated wastewater. Therefore, the study assessed the crop, environmental and health risks when irrigating with anaerobic filter (AF) effluent using the Decision Support System (DSS) of the South African Water Quality Guideline model, in four South African agroecological regions, three soil types, two irrigation systems and three different crops. The model was parameterised using AF effluent characterisation data and simulated for 45 years. The model predicted that there are no negative impacts for using AF effluent on soil quality parameters (root zone salinity, soil permeability and oxidisable carbon loading), leaf scorching and irrigation equipment. The problems were reported for nutrient loading (N and P) in maize and microbial contamination in cabbage and lettuce. It was recommended that the effluent should be diluted when used for maize production and advanced treatment should be explored to allow unrestricted agricultural use.
Highlights
Global water supply is threatened by population dynamics, characterised by excessive urbanisation
As knowledge was gained and practices changed with time, the South African Water Quality Guideline (SAWQG) was developed in 2017 to include developments not addressed in the Department of Water and Sanitation [11] guidelines
The anaerobic filter (AF) effluent can be used in any soil type and South African climatic region without negatively affecting soil quality parameters such as root zone salinity, soil infiltrability, hydraulic conductivity and oxidisable carbon loading, regardless of climatic region and irrigation system
Summary
Global water supply is threatened by population dynamics, characterised by excessive urbanisation. In South Africa, about 63% of the people are living in urban areas and this figure is expected to reach 71% by the year 2030 [1]. This is straining on municipal service delivery as they are failing to provide adequate housing, sanitation and clean water. The DEWATS is a modular system that comprises of the settler, anaerobic baffled reactor (ABR), anaerobic filter (AF) and planted gravel filters (PGFs). The final DEWATS effluent may not meet the stringent South African discharge quality Discharging it into water bodies may cause pollution, evidenced by algal blooms, death of aquatic life and sometimes expose people to waterborne diseases. To ensure sustainability the development of sanitation systems should be linked to agriculture in a way that solves socio-economic challenges in low-income communities while protecting the environment
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
