Ultrafiltration Circulating Tank for Waste Emulsion Treatment
Emulsified oily water presents a difficult treatment problem in a large number of metal fabricating and machining industries. The conventional methods of disposal include chemical treatment, incineration and haulage by the waste disposal companies. This paper describes a new approach for the treatment of the oily waste water.
A typical system would include pre-treatment (such as settling or screening), ultrafiltration and some post-treatment. If the oil can be recycled, the post treatment is generally settling to increase the concentration of the oil. If the oil cannot be recycled, the post-treatment is usually incineration. The concentration of the recovered oil can be as high as 90% oil by volume.
The ultrafiltration system dewaters the oily water solution up to 90% as it passes over the membrane system developed by Electrohome. Each module contains tubes that act as the pressure vessels supporting the cylindrical membranes. With each pass through the tubes water is removed and the oily water gets more concentrated.
Introduction
Ultrafiltration is filtration on a molecular level. Its basis is a membrane of controlled pore size which discriminates between large and small molecules. The molecules retained by the membrane may be dissolved in solution or they may be visible aggregates.
The liquid to be treated is applied against a membrane surface under controlled conditions of pressure and flow. The membrane allows water and smaller molecular components in water to go through the membrane. This stream is called the permeate. The larger molecular components do not go through the membrane and get concentrated in the water. This stream is called the concentrate.