Industry brief 2020 Reusing wastewater

This 2020 industry brief by GreenCape examines the on-site treatment and reuse of grey- and blackwater to non-potable standards in South Africa. It outlines the technical processes for treating organic wastewater, the various technology variants available (such as pre-fabricated or constructed systems), and the regulatory landscape governed by the National Water Act and the National Environmental Management Act. The document highlights the economic and operational drivers for on-site treatment in both urban and rural settings, providing case studies from the Western Cape to demonstrate water and cost savings.

• South Africa faces significant water scarcity, with a projected 30% water supply deficit by 2030. The reuse of wastewater, alongside increasing water-use efficiency and alternative water sources, is identified as a primary intervention to mitigate this deficit.
• On-site wastewater treatment is particularly viable for residential and commercial buildings (such as hotels, schools, and offices) because these entities typically have a higher demand for non-potable water than potable water and produce organic wastewater (grey and blackwater).
• The drivers for on-site treatment vary by setting: in urban areas, it is driven by the high cost of potable water and restrictions on its use for irrigation; in rural areas, it is driven by the high cost or impossibility of connecting to municipal sewers and the future ban on septic tanks.
• Organic wastewater is typically treated through a four-step biological process: screening of large solids, primary settling (anaerobic digestion), secondary settling (aerobic treatment via methods like Activated Sludge or Sequential Batch Reactor), and final clarification and disinfection (using UV, ozone, or chlorination).
• On-site treatment systems face several operational risks and barriers, including the potential for inorganic contaminants to kill the bacteria required for treatment, difficulties managing variable wastewater volumes (seasonal loading), high upfront costs, and the need for periodic de-sludging.
• Wastewater discharge is regulated by the National Water Act (NWA), requiring registration with the Department of Human Settlements, Water and Sanitation (DHSWS). Depending on the daily discharge volume and location (such as sensitive catchments), a General Authorisation may apply, or a Water Use Licence may be required.
• The National Environmental Management Act (NEMA) mandates environmental impact assessments (EIA) or basic assessments based on plant capacity: throughput between 2,000 kl/day and 15,000 kl/day triggers a Basic Assessment Process, while capacity exceeding 15,000 kl/day triggers a Scoping/EIA Process.
• Case studies in the Western Cape demonstrate the efficacy of on-site treatment: a provincial government building saved approximately 1 million litres of potable water per year, and a study on informal settlements found that decentralised wastewater treatment is the lowest cost technology option compared to centralised connections or chemical toilets.

APA

Kruger, R. (2020). Industry brief 2020 Reusing wastewater. GreenCape. https://greencape.co.za/assets/WASTEWATER_TREATMENT_INDUSTRY_BRIEF_WEB-13-11-2020.pdf

Chicago

Kruger, Raldo. Industry brief 2020 Reusing wastewater. GreenCape, 2020. https://greencape.co.za/assets/WASTEWATER_TREATMENT_INDUSTRY_BRIEF_WEB-13-11-2020.pdf.

Wikipedia

{{cite report |last1=Kruger |first1=Raldo |title=Industry brief 2020 Reusing wastewater |publisher=GreenCape |date=2020 |url=https://greencape.co.za/assets/WASTEWATER_TREATMENT_INDUSTRY_BRIEF_WEB-13-11-2020.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{kruger2020industry, author = {Kruger, Raldo}, title = {{Industry brief 2020 Reusing wastewater}}, institution = {GreenCape}, year = {2020}, url = {https://greencape.co.za/assets/WASTEWATER_TREATMENT_INDUSTRY_BRIEF_WEB-13-11-2020.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }