Mono Muncher reduces bulk tannery waste

Animal byproduct regulations and rising disposal costs have led Scottish tannery W J & W Langs to install a Mono Muncher at their plant in Paisley to reduce bulk waste and improve the efficiency of composting as an alternative to landfill. Each month the tannery produces approximately 500 tonnes of fleshings, a bulky waste product stripped from the hides prior to tanning. More stringent restrictions on disposal led the tannery management to look for a better way of dealing with the waste, and so they turned to Mono's Scottish distributor, Clyde Associated Engineers, who had previously helped them to improve their waste handling on site. Eight years ago a Mono W Range wide throat pump was installed to pump tannery waste 30 metres directly to a waste disposal area, creating a more hygienic and enclosed waste disposal system. Specially designed to efficiently pump material with a high solids content, the W range pump removed the need for manual handling of the fleshings and the constant 30-minute cycle of filling and forklifting away skips full of the material. In the latest development, a Series 'A' Muncher has been installed on the vertical pipeline of the pump discharge to process the waste fleshings. The fleshings are macerated to a small particle size to assist the biological breakdown of the material and are then collected by a waste management company and composted for use as top soil for extinct landfill sites, or as fertiliser. The tannery engineering manager William Alexander is delighted with the efficiency of the new process. He explains: 'The cost of waste disposal has been substantially reduced by macerating the fleshings and sending them on for composting, but the benefits are more than just monetary. The process is far more efficient, easy to maintain, and has resulted in a safer working environment.' The Mono Series 'A' Muncher is a twin-shaft, low speed, high torque grinder. Biodegradable waste is fed into the Muncher to pass through a series of cutters, which revolve at differential speeds to pull apart, crop and shear any solids. Liquid passes through the cutter stacks, whilst the solids are trapped and macerated to a small, consistent particle size, to help comply with legislation and improve process efficiency. The Muncher's integral gearbox converts its relatively low motor power into high output torque to make the unit extremely powerful but also energy efficient. The low revolving speed of the cutter shafts, typically 45 rpm, creates low cutter tip speeds and this dramatically reduces wear rates and noise levels compared to high speed macerators. A PLC is incorporated into the control system to protect the Muncher from overloading. The Mono W Range Widethroat pump operates at a speed of 89rpm and delivers the fleshings waste at 5m³/h, at a pressure of 3 bar. The pump features a nitrile rubber stator and stainless steel rotor. The W Range can handle materials with viscosities up to 1,000,000 centipoise.