Heritage Cases

The proposed project entails the construction of a Sewage Package Plant (SPP) on Robben Island. The SPP will be used to treat sewage effluent generated on the island, which will be transported to the nearby existing sea outfall pipe (constructed in 2000) where sewage is currently discharged at a distance of 465m from shore. The current marine outfall on Robben Island was designed to discharge an effluent comprising raw macerated sewerage. This has historically been under permit to comply with the Marine Water Quality Guidelines for the South African Coastal Zone (DWAF, 1995) within an acceptable distance from the offshore discharge point through dilution. A treatment facility is now required to ensure that the effluent reaches the required discharge concentrations. The facility has been designed to achieve the General Limit Values (GN 665 of 2013) for the disposal of wastewater to a water resource in terms of Section 39 of the National Water Act, 1998 (Act No 36 of 1998). The primary motivation for the project is that currently there is no wastewater treatment infrastructure on Robben Island. The SPP will therefore serve to provide vital infrastructure for the island. The treatment throughput capacity of the plant is designed to be approximately 300m3 per day, or 108,000m3 per annum. Raw sewage will be collected in the existing inflow collection sump, where it will be macerated and transferred into the treatment plant. Following treatment, effluent will be transported via an existing pipeline to the existing marine pump station where it will be transferred to the existing marine outfall pipeline and discharged to sea. The plant includes a 240m3 storage tank to store treated effluent for irrigation of nearby sports fields in the future As a by-product of the process, an estimated 120m3 of sludge will be generated annually. The sludge will be inert as a result of the bacteriological breakdown that occurs during extended biological treatment within the chambers. This means that the sludge will be a “spent” by-product with no metabolic activity. Sludge will be transferred to a drying bed (DB) located directly adjacent to the facility and disposed of via the normal refuse system (appropriately licenced landfill site) or to a municipal wastewater treatment works (WWTW). Ancillary infrastructure will include a new sewer pump and blowers to support the existing pump station