The Welgedacht WCW is situated in the DD4 area with a design capacity of 95 Mℓ/d which utilizes activated sludge processes to treat its influent, which is 20% industrial and 80% domestic. Welgedacht has two modules; Module 1 which is a 35 Mℓ/d Surface Aeration plant and Module 2 which is a 60 Mℓ/d Diffused Air Aeration plant.
Each module has its own inlet works which comprises of screening system and degritting systems. The process comprises the following stages: Three sets of Archimedean screw pumps lift the raw water into the inlet works in two stages. Two coarse screens followed by two automatic fine screens and screw compactor are used to remove rags from the influent. Grit is removed in two degritters.

The Reactor (Module 1) utilises a 5 stage Phoredox process configuration, with the following zones: anaerobic anoxic, aerobic, second anoxic followed by re-aeration. Aeration is by 16 surface mounted aerators and mixing by 13 submersible mixers. Effluent from the reactor flows into three parallel biological clarifiers from which the underflow is recycled back to the anaerobic zone of the reactor. Excess sludge is wasted from the underflow. The clarifiers overflow to three chemical clarifiers where ferric chloride is used for additional phosphate removal.

Module 2 is equipped with two balancing tanks to equalize diurnal flow patterns. It also has primary sedimentation tanks, and settled wastewater is treated in their respective bioreactors. Secondary sedimentation is employed for all modules to separate the activated sludge from the liquid. The treated effluent from Module 2 goes through sand filters before disinfection whereas those from module 1 goes straight to disinfection after secondary sedimentation. The effluent from both modules are combined and discharged within the Blesbokspruit stream.

The sludge handling facilities comprises of 2 heated and mixed primary anaerobic digesters and 3 belt presses. The primary sludge is first screened and pumped to the two primary anaerobic digesters. The heating system of the digester comprises of a boiler and two heat exchangers, one per digester. These are used to heat and keep the temperature within the digester to acceptable levels. When the digesters fill up, sludge is sent to the sludge holding tank through gravity. At that point, digested sludge can either be sent to de-watering facility for further processing or to land for disposal. The gas produced in this system is sent to the Gas Holding Tank for storage, from the Gas Holding Tank it can be sent to Boiler or the Flare for burning.