Frito-lay required the operation, maintenance and optimisation of 2 effluent treatment plants located at Isando and Parow respectively. The primary purpose of these plants is to reduce the chemical oxygen demand (COD) and total suspended solids (TSS) levels in the factory wastewater before discharging it to sewer in order to reduce the costs associated with waste treatment. In addition, the recovery of potential by products from the effluent is an added benefit.
PROXA provided the client with skilled members of staff to operate the facilities 24/7, together with ongoing technical support in the form of overall water balance studies to identify and implement ways to reduce the amount of water waste generated on the site, and where possible, maximise reuse.
The effluent plants comprised of solids removal via screening and subsequent settling of the screened effluent. As useful by-products, it generates large volumes of screenings and dewatered grey starch.
Raw effluent from the plant is collected and pumped across a rotary screen. The water discharged from the rotary screen and screenings press is fed to a clarifier.
Final dewatering is done in a decanter centrifuge. The solids (by-product) discharge from the centrifuge is collected by a third party and used as animal feed. Final effluent is released into the sewage system.