Renewable energy and energy efficiency technologies for wastewater treatment works in South Africa

The document identifies the secondary treatment stage as the highest energy consumer in wastewater treatment works, particularly in systems using activated sludge where aeration can account for 50% of process energy. It recommends benchmarking specific power consumption (SPC) and implementing interventions such as fine bubble aeration, dissolved oxygen control, and cascade aeration to reduce costs and greenhouse gas emissions. Financing options for these projects include municipal budgets, grants, concessional loans, and energy performance contracts.

• Water supply and wastewater treatment account for approximately 17% of the total energy used by municipalities in South Africa. Within a wastewater treatment work (WWTW), the secondary treatment stage is the most energy-intensive phase, offering the greatest potential for energy savings through renewable energy and energy efficiency measures.
• Systems utilizing activated sludge have higher specific power consumption (SPC) due to aeration and pumping requirements; in newer facilities, aeration alone often represents about 50% of the total energy used in the treatment process.
• Low-cost measures including energy monitoring, skills training, and energy assessments can result in energy savings of up to 20%. More technical interventions in the aeration system, such as switching to fine bubble aeration or dissolved oxygen control, can save between 30% and 70% of total aeration system energy consumption, with retrofits having an estimated payback period of 3 to 7 years.
• The document identifies several financing mechanisms for energy efficiency projects in WWTWs, including municipal budgets, government or donor grants (such as MIG, RBIG, and WSIG), concessional loans from foreign funders (e.g., AFD, SEFA, DBSA), commercial bank loans, and energy performance contracts via Energy Services Companies (ESCos).

APA

GreenCape (n.d.). Renewable energy and energy efficiency technologies for wastewater treatment works in South Africa. https://greencape.co.za/wp-content/uploads/2023/08/Factsheet-5_Energy-Efficiency-in-Secondary-Treatment-Technologies.pdf

Chicago

GreenCape. Renewable energy and energy efficiency technologies for wastewater treatment works in South Africa. n.d. https://greencape.co.za/wp-content/uploads/2023/08/Factsheet-5_Energy-Efficiency-in-Secondary-Treatment-Technologies.pdf.

Wikipedia

{{cite report |author=GreenCape |title=Renewable energy and energy efficiency technologies for wastewater treatment works in South Africa |url=https://greencape.co.za/wp-content/uploads/2023/08/Factsheet-5_Energy-Efficiency-in-Secondary-Treatment-Technologies.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{greencapendrenewable, author = {{GreenCape}}, title = {{Renewable energy and energy efficiency technologies for wastewater treatment works in South Africa}}, institution = {GreenCape}, url = {https://greencape.co.za/wp-content/uploads/2023/08/Factsheet-5_Energy-Efficiency-in-Secondary-Treatment-Technologies.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }