by Dave Cochrane
We had a very encouraging meeting with ERWAT and their project management team at the Olifantsfontein Waste Water Treatment Works on 28 May 2019. ERWAT gave a presentation which acknowledged that the discharge is not compliant, explained the problems that they need to overcome, and gave information on their short term and long term project plans. Most importantly, Mr Fortune Mabunda (Executive Director of Operations at ERWAT) confirmed that they have received the funding that they require for the capital expenditure required for the project, and they will provide us with details of the short and long term project plans and progress reports.
The Olifantsfontein WWTW is operating at an average of 116 Ml/day, which is 26 Ml/day above the design capacity of 105 Ml/day. One of the 3 modules in the plant is not operating properly (more info below). As a result the water discharged from the plant into the Kaalspruit is not compliant. Added problems are storm-water ingress when it rains, and the ingress of fine sand. 40% of the effluent received is from industry. Mr Justice Maluleke (Director: Water Regulation and Use Department of Water and Sanitation) informed us that Ekurhuleni is monitoring the discharge from industry and has cautioned and fined industries in the area that do not comply. The plant has 3 Modules. Modules 1 and 2 of the plant are operating properly. We could see the clear water from the end of the process. The primary settling tank (PST) of Module 3 is not operational. This PST has been damaged due to a sink hole, cannot be repaired. It has not been operational since 2016. As a result, partially treated effluent flows directly into the biological nutrient reactor (BNR). The BNR cannot operate properly and solids block up the BNR and flow through the system. Water from the end of this process is opaque with solids and foamy. The discharge water from Module 3 is combined with the clear water from Modules 1 and 2 before being discharged into the Hennops, but the combination is not compliant. The WWTW will build a new PST for module 3, but this will take 24 months. In the meantime, the WWTW is recommisioning 6 small disused primary settling tanks and 6 biosettling tanks. We could see that work has started. Once these tanks are operational, effluent will be treated by them prior to the BNR, which will improve the operation of the BNR by the end of 2019. Bryan, the project manager, did caution that they are still checking the integrity of the primary settling tanks and biosettling tanks that they intend to recomission. An area that does concern me are the dams that are used for storing effluent (black sludge) when there is overcapacity. These dams are located very close the the Kaalspruit and discharge point. This creates a risk of this effluent flowing directly into the Kaalspruit. The WWTW will address the lining of these emergency dams once the other critical issues have been dealt with. The Plant Manager has confirmed that the effluent cant flow directly into the Kaalspruit. Having spoken to the project managers and having seen what is being on-site it would appear to me the the WWTW are doing the best that they can to alleviate the problem in the short term and the long term. I am grateful for the transparent and detailed information that the WWTW provided, and their willinglness to share their project plans and keep us informed of progress. The Hennops River Forum took a decision at the March 2019 meeting that an ERWAT site meeting should took place. Thank you to Mr Justice Maluleke and Ms Esmy Madumo from the Department of Water and Sanitation for scheduling the meeting with ERWAT and attending the site visit.