Project Assignments is currently providing professional services to City of Cape Town for multiple wastewater plant (WWTP) upgrades. The work recently completed and currently in progress includes:
- Replacement of the fine bubble diffused air networks at Cape Flats, Mitchells Plain and Wesfleur;
- Mechanization of portable flush toilet cleaning at Borcherds Quarry WWTP – faecal sludge management;
- Odour control and HVAC at Bellville WWTP and Green Point marine outfall;
- Odour control at faecal sludge management facility at Borcherds Quarry;
- Replacement of activated sludge aeration blowers at Bellville WWTP;
- Upgrade of Bellville dissolved aeration (DA) plant to a full biological nitrogen and phosphorus removal system complete with all new rotating equipment and fine bubble aeration networks;
- New coarse screening and grit removal facility upstream of Borcherds Quarry inlet works;
- Refurbishment of Athlone WWTP: new mixers, recycle pumps, fine bubble diffused aeration systems, and aeration blowers,
- Upgrading of Cape Flats sludge digestion to include thermal hydrolysis pre-treatment. The new facility will enable both on-site and imported sludge (from other Cape Town sites) to be digested, producing Class A1a sludge, also delivering 6MW of electrical power and a useful, safe, final biosolids stream;
- Nitrogen removal from digestate liquor at Cape Flats WWTP using anammox technology;
- Replacement of all rotating equipment (mixers and pumps) at both Mitchells Plain and Cape Flats WWTP’s.
Project Assignments is acting as the process and mechanical engineers for the main contractor in a project to construct a greenfields domestic wastewater treatment plant at Nhlangano in Eswatini (formerly Swaziland). The plant comprises screening and grit removal, primary sedimentation, two-stage trickling filters (including nitrification and denitrification), final sedimentation, dual media filtration and ultraviolet disinfection of the final effluent. The plant also includes full sludge handling: thickening, anaerobic digestion, biogas storage and flaring, digested sludge storage and sludge drying beds. The plant is fully automated with a centralised control system. The project is in the final stages of mechanical installation.
For GlaxoSmithKline in Cape Town, Project Assignments recently completed a groundwater abstraction and treatment plant, to ensure that GSK have security of water supply for continued safe operations during times of water shortages. The plant included iron and manganese removal followed by reverse osmosis membrane treatment and stabilisation.
For BBI Solutions, Project Assignments has also recently installed a groundwater abstraction and treatment system for the factory in Epping. Like the GSK plant, this installation also included pre-treatment to remove iron and manganese then reverse osmosis and remineralisation.
For Lactalis, Project Assignments is acting as the client’s Engineer in the design and construction of a greenfields industrial activated sludge wastewater treatment plant at their Bonnievale cheesemaking factory. The project will include screening, grit removal, dissolved air flotation, activated sludge, final effluent disinfection and waste sludge dewatering.
Project Assignments is currently conducting a preliminary design and costing exercise for Zimplats in Zimbabwe, to recycle 5.6 Ml/d of treated wastewater for re-use at their Ngezi platinum concentrator, reducing the dependence on potable water. The proposed process train includes coagulation & flocculation, sedimentation, ultrafiltration, reverse osmosis and stabilisation. The brine shall undergo forced evaporation.
For eThekwini Municipality, Project Assignments is working with JG Afrika to upgrade the Hammarsdale WWTP inlet works as well as the sludge dewatering infrastructure. Detailed design is complete and specifications for tender are in progress.