Civil Engineering July 2021 | Vol 29 No 6

Civil Engineering July 2021 41 L ocated in the province of KwaZulu- Natal, the South Durban Basin is the industrial hub of Durban. This area stretches from the Port of Durban in the north, to eZimkokodweni in the south and is home to two large petrochemical refineries, a large paper mill, motor manufacturers and at least 5 000 busi- nesses. The area is also densely populated, with two main residential areas housing 200 000 residents. During the 1930s the South Durban Basin was planned as an industrial hub, but in the 1950s, through the enforcement of the Group Areas Act, minority ethnic communities were often relocated adja- cent to the heavy industries. The discharge of effluent from the Southern Wastewater Treatment Works (WWTW) into the Indian Ocean via a 4.5 km, 230 Mℓ/d sea outfall at Cuttings Beach has occasionally been an additional point of controversy and aggravation for the local community. Prior to the com- missioning of the sea outfall, most of the catchment’s wastewater was discharged directly into the entrance of the Durban Bay channel, resulting in pollution and public health concerns. In 1964 the Durban Corporation investigated the feasibility of the wastewater being discharged via a deep- water outfall. Following confirmation, the outfall was constructed in 1968. 15 years after the outfall was commis- sioned, the Department of Water Affairs permitted the discharge of raw sludge into the ocean without the prior removal of solids. During peak flows, and under normal operations, the effluent could bypass the low-level storage tanks and was discharged by gravity through diffusers along the sea outfall and pumped out to sea. However, given the large catch- ment area that the WWTW services, peak wet weather conditions resulted in exponentially greater flows at the plant, meaning that the pumping system was not able to discharge effluent via the sea outfall quickly enough to draw down the low-level storage tanks. Namrata Jugwanth Engineer AECOM namrata.jugwanth@aecom.com Southern WWTW upgrade: infrastructure solutions enhance communities and environments AECOM was appointed to provide project management and contract administration services on the first phase of the planned upgrades at the Southern Wastewater Treatment Works in the South Durban Basin. With an obstinate focus on social impact, this phase comprised solutions that enhance the surrounding community and environment. Construction of the reinforced concrete cradle in which the 1000ND HDPE pipes are housed