DAF pump saves capital, energy and maintenance costs

A single DAF (dissolved air floatation) pump is said to be able to replace the entire air bubble system on DAF plants, according to pump supplier Hydro Innovations. The company’s Edur Multiphase pumps draw in air through a ‘snorkel’ in the suction line, sheer the air, then feed it into the DAF plant, producing a discharge stream into the tank that is saturated with 30 to 50 micron air bubbles.

Conventional DAF systems normally consist of a wastewater tank, compressor, air saturation vessel and effluent pump. The effluent pump draws effluent from the tank and pumps it into the air separation vessel. A compressor pumps air into this same vessel. The air/water mixture is ‘saturated’ under pressure then released back into the wastewater tank at atmospheric pressure where tiny bubbles form and adhere to the suspended matter (fats, oils and other small wastewater particles). The bubbles (with their attached suspended matter) float to the surface of the tank where floatables can be skimmed off the surface.

By using Edur Multiphase pumps, which can produce their own microbubbles, asset owners can do away with the compressor, the air saturation vessel and any control and/or ancillary components for these items. The reduction of these system components and the simplification of the system design is said to result in lower investment costs and higher operational reliability.

The Edur Multiphase DAF pump is also an efficient alternative, with one pump replacing the conventional pump, air saturation tank and compressor. Energy and maintenance costs of running the compressor are therefore eliminated.

Edur multiphase pumps can deliver flows from 1 L/s (for smaller DAF plants) to 15 L/s (for larger DAF plants) and produce pressures to 12 bar. A variety of materials and seal arrangements enable the pumps to operate in a very wide range of applications. Available materials include ductile iron, ‘gunmetal’ bronze, stainless steel and super duplex. Mechanical seals are available as balanced, double and tandem.