Upgraded DAF system for Cedar Meats

Cedar Meats is a state-of-the-art meat exporter in Victoria with a continual improvement philosophy. The company needed to upgrade its dissolved air flotation (DAF) system but did not want to just go for a ‘standard’ system. It wanted a more energy-efficient system — one that could deliver low running costs for the life of the system.

The ‘conventional’ system consists of a centrifugal pump that pulls clean effluent from the DAF tank and feeds it into a pressurised air saturation vessel. A compressor also feeds compressed air into the same vessel and the air saturates into the effluent water. The water is then fed back into the bottom of the DAF tank where the air comes out of solution to form tiny bubbles, which attach to fats and grease in the system and float it to the top of the tank where it is scraped away.

The system requires a control system to combine air and water needs, and it requires regular certification of the pressure vessel. There is also maintenance of the pump, compressor and pressure vessel to consider, along with energy consumption of both pump and compressor. Capital costs and running costs are not cheap.

Cedar Meats Chief Engineer Yogesh Mistry went looking for a solution that did not involve intricate and delicate control systems and did not need ongoing WorkSafe certification for pressure vessels. He contacted Hydro Innovations to get information on the EDUR DAF pump he had read about.

EDUR, a German pump manufacturer, has developed a multistage ‘multiphase’ pump capable of handling a gas/water mixture, making it ideal as a DAF pump. The pump draws clean effluent from the DAF tank and, at the same time, draws in atmospheric air on the suction side of the pump. The pump sheers and mixes the air with the water, and under pressure from the multistage pump, air saturates into the effluent water. The water is then pumped into the bottom of the tank, where the air comes out of solution, as in conventional systems. No compressor or air saturation pressure vessel is needed.

Mistry was impressed with the simplicity of the system and promptly arranged the purchase of an EDUR DAF pump. He has been pleased with the positive results, which include: a higher rate of solids removed; less power used for the job, reducing power costs; less complicated controls; and a low-maintenance future ahead for the system.