The Problem The pumps in a large 25m wide and 21m deep inlet pumping station at a wastewater treatment works were frequently blocking due to the volume of silt and screenings in the wet well. The Solution The thick layer of sludge, screenings and silt in the wet well was rst removed using a DISAB vacuum tanker working from the top only. As the levels of sludge, screenings and silt in the tank decreased a safe working area was cleared in the tank. Once the tank was deemed to be safe to enter after gas testing, two conned space trained operators were lowered into the wet well using a man riding basket and mobile crane. A further mobile crane and man riding basket was on standby at all times. When the operators were safely on the base of the well, the remaining material was broken up usi

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