Acids, alkalis and plastic sacks - solving a difficult sump pumping problem

Where a variety of other pumps have failed, an SPX50 hose pump handles a difficult effluent pumping duty at a chemical supplier. Aggressive chemicals, together with abrasive grit and items such as wire, tie wraps, labels and bottle tops create a seemingly unlikely mixture for a sump pump to handle.

All effluent and surface run-off from the entire site of a North Western chemical supplier drains into a centrally located, six metre deep collection sump. The effluent produced can be acidic or alkaline with up to 10% solid content, often consisting of sodium bisulphate, caustic potash, hydrochloric and sulphuric acids in varying concentrations.

Operating automatically under the control of high and low level float switches, the Watson-Marlow Bredel SPX50 pumps from the sump against a head of approximately three metres, to the Company’s effluent treatment plant.

Other pumps including submersibles, air operated double diaphragm and various centrifugal and positive displacement designs had all been unable to cope to varying degrees, with the combination of solids, acids and other aggressive chemicals. As well as corrosion and abrasive wear of these pumps, pump blockage was a frequent problem.

With its “straight through” flow path there are no vanes, valves, rotors or pistons to corrode or impede the flow of solids. The heavy duty SPX50 pump is fitted with an abrasion resistant EPDM hose - the only component in contact with the effluent. The occasional hose blockage is inevitable when handling materials such large and irregular shaped solids, but can often be cleared by simply reversing the pump.