The plant currently does not comply with the DWA wastewater discharge standards. There are major challenges with respect to operation, maintenance and some equipment status at the plants. Some of the problems identified that are hampering the non-compliance of the final effluents are as follows:
• Flow meters are not calibrated (incorrect flow readings) and this makes it difficult to optimize the plant with respect to flows into different modules, i.e. Activated Sludge plant and the trickling filter plant.”
• Over aeration (due to the oversized aerator blades) taking place in the extended aeration basin causing excessive foaming in the biological reactor and final settling tank.
• The internal Recycle Pumps in the aeration are not Variable Speed Drives (VSD) as a results incomplete treatment is taking place in the reactor and a high current is pulled by these pumps.”
• The suction lift clarifier scum box not working resulting in the excess scum formation on the clarifier and non-compliant of effluent being discharged into the river. Two of the suction lift valves (siphons) kept on blocking due to the high sludge concentration in the clarifier resulting in sludge carry-over to the river.”
• Three bio-filter are non-operational due to the defective central columns and structures.
• All six sludge digesters are full of grit and sand thereby reducing the working volume of the digesters and the efficiency of the sludge treatment. Some of the valves at the digesters are old and defective making it difficult to operate the digesters at full capacity.
• Some of the sludge drying beds are defect and need urgent repair for sludge handling purposes.
• There are not enough process control instruments for plant optimization and control; instruments such as Dissolved Oxygen Meter, pH Meter (for sludge digestion), Ammonia and phosphate kits.
• The plant does not have a proper chlorine contact chamber for