A TECHNOLOGICAL AND ECONOMIC EXPLORATION OF PHOSPHATE RECOVERY FROM CENTRALISED SEWAGE TREATMENT IN A TRANSITIONING ECONOMY CONTEXT

The study evaluates three methods for managing phosphate at the Cape Flats WWTW: high-grade struvite production, low-grade struvite production, and chemical precipitation. While chemical precipitation has the lowest initial capital expenditure, low-grade struvite production is identified as the most economically and ecologically sustainable option over a 20-year period, with a net present cost of R25.4 million compared to R51.2 million for chemical precipitation and R76.2 million for high-grade struvite. Despite these relative advantages, the study finds that struvite production is currently unprofitable due to low local market prices for phosphate fertilizers and high capital costs, suggesting a need for new policies that treat phosphate as a resource rather than a pollutant.

• Low-grade struvite production is the most economically and ecologically sustainable option from a life-cycle-costs perspective, with a net present cost of R25.4 million over a 20-year lifetime.
• Chemical precipitation is the most affordable option in terms of initial capital expenditure (CAPEX), but it is more expensive than low-grade struvite production over the long term, with a net present cost of R51.2 million.
• High-grade struvite production is the least viable option due to high capital costs and a significant electrical and carbon footprint, resulting in a net present cost of R76.2 million.
• Struvite production at the CFWWTW is currently unprofitable, recovering only 4.21% to 7.98% of operating costs, largely because South African phosphate fertilizer prices are too low to offset recovery costs.
• Market analysis suggests that the South African food market may resist fertilizers derived from human waste, making low-grade struvite for non-food secondary markets, such as ornamental plants or commercial fertilizer production, more feasible.

APA

Sikosana, M. K., Randall, D. G., & von Blottnitz, H. (n.d.). A TECHNOLOGICAL AND ECONOMIC EXPLORATION OF PHOSPHATE RECOVERY FROM CENTRALISED SEWAGE TREATMENT IN A TRANSITIONING ECONOMY CONTEXT. GreenCape. https://greencape.co.za/assets/Sector-files/water/Innovation/Sikosana-et-al.-A-technological-and-economic-exploration-of-phosphate-recovery-from-centralised-sewage-treatment-2015.pdf

Chicago

Sikosana, Melissa K.L.N, Dyllon G. Randall, and Harro von Blottnitz. A TECHNOLOGICAL AND ECONOMIC EXPLORATION OF PHOSPHATE RECOVERY FROM CENTRALISED SEWAGE TREATMENT IN A TRANSITIONING ECONOMY CONTEXT. GreenCape, n.d. https://greencape.co.za/assets/Sector-files/water/Innovation/Sikosana-et-al.-A-technological-and-economic-exploration-of-phosphate-recovery-from-centralised-sewage-treatment-2015.pdf.

Wikipedia

{{cite report |last1=Sikosana |first1=Melissa K.L.N |last2=Randall |first2=Dyllon G. |last3=von Blottnitz |first3=Harro |title=A TECHNOLOGICAL AND ECONOMIC EXPLORATION OF PHOSPHATE RECOVERY FROM CENTRALISED SEWAGE TREATMENT IN A TRANSITIONING ECONOMY CONTEXT |publisher=GreenCape |url=https://greencape.co.za/assets/Sector-files/water/Innovation/Sikosana-et-al.-A-technological-and-economic-exploration-of-phosphate-recovery-from-centralised-sewage-treatment-2015.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{sikosanandtechnological, author = {Sikosana, Melissa K.L.N and Randall, Dyllon G. and von Blottnitz, Harro}, title = {{A TECHNOLOGICAL AND ECONOMIC EXPLORATION OF PHOSPHATE RECOVERY FROM CENTRALISED SEWAGE TREATMENT IN A TRANSITIONING ECONOMY CONTEXT}}, institution = {GreenCape}, url = {https://greencape.co.za/assets/Sector-files/water/Innovation/Sikosana-et-al.-A-technological-and-economic-exploration-of-phosphate-recovery-from-centralised-sewage-treatment-2015.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }