Pretreatment of organic effluents 

The decantation is a mechanical operation of separation, under the action of the gravitation, with several not-miscible phases of which at least one is liquid. Several not-miscible liquids of different densities can be thus separated or insoluble solids in suspension in a liquid.

The screen cleaner is intended to retain the bulky matters and waste of all kinds contained in the waste water. It is located generally upstream of waste water treatment. The operation is more or less effective according to the spacing between the bars of the grid. According to the characteristics of water to be purified and the following stages of the treatment, grids with different spacings can be placed the ones behind the others or separately (finer cleaning just upstream of a stage of critical treatment).

Process consisting in improving separation of the suspended matter and greases in waste water by means of air injection.

Process of purification consisting in gathering the impurities in suspension in a liquid. Flocculation is in general preceded by a coagulation and is followed of a decantation, centrifugation or of aero flotation.