EWRP management of clarifier sludge

The Emalahleni Water Reclamation Plant (EWRP) treats acidic mine water from five mining operations. The feeds vary from a pH of 6 to a pH as low as 2.3. Over the last few years, the water qualities have deteriorated drastically. Mine life-extension projects have also required the removal of more acidic water, which has altered the total feed composition to the EWRP. This change specifically came about in the form of iron load. The initial design of the treatment process was to treat iron levels up to 300mg/l. The incoming feed quality at the time was more than 450mg/l IRON. From November 2023 to January 2024, the mining operation was almost completely stopped due to an excessive amount of water. Due to significant production pressure, the operation had to adapt and treat the higher iron loads with no time to make significant design, construction or installation changes. The biggest challenge was clarifying the water, as iron is typically a low-density substance that struggles to settle at higher throughputs. This began an eight-month journey with many ideas, failures, theories, and eventually success. At the end of April 2024, all the water-related stoppages were resolved and by June 2024 the mine was dry and operations could continue.