A large wastewater treatment plant in New South Wales had been struggling to overcome problems with pumps and pipework clogging with clumps of rag and ropey fibrous material in municipal sewage. The existing failing pumps were eventually replaced with two model SP4K Vaughan self-priming chopper pumps, which incorporate patented and innovative design features that allow them to chop and pump heavy, solids-laden waste material without the risk of clogging.