Outeniqua Wastewater Treatment Works: Upgrading and 10Ml/d Capacity Extension
Air blowers installation under way for air delivery to provide oxygen to the aerobic zones in the reactor.
Works at the Outeniqua Wastewater Treatment Works (OWWTW) for the upgrading and capacity extension of the plant are well under way and progressing steadily. The upgrade will allow for an increased capacity from 15Ml/dl to 25Ml/dl.
The components at the inlet works are nearing completion and are being commissioned as the installations are completed. The new perforated inlet screens are operational as well as the screenings and grit bins and the grit removal systems while the rock catcher and odour control systems are nearing completion. The remainder of the works largely focuses on the completion of equipment installation in and around the new reactor whereafter the focus will shift to the upgrading of the screw pump station for the sedimentation tank underflow sludge recycle.
After the commissioning of the new reactor, the full flow to the works will be diverted though it and this will allow the remedial works to the existing (old) carousel reactor to proceed. This tank of 17.5 Ml needs to be emptied and the concrete condition to be assessed with the necessary remedial and repair works to follow. The screw pump station for the Return Activated Sludge recycle also requires upgrading. The two new pumps were shipped to South Africa from Italy, and have arrived finally after a four month delay in Las Palmas, Canary Islands. This caused a project delay of this component of the project but will not have an impact on the final estimated completion time.
The major challenge will be to empty the old carousel reactor while separating the liquid from the various inorganic (non biodegradable) solids in the tank. These solids must be dewatered and disposed of separately. The contractor proposed geofabric bags for this dewatering and is currently experimenting with a small version on site. The mechanical & electrical installation is currently 70% complete and the construction is scheduled to be completed during the first half of 2023.