1 PHYSICAL SYSTEM: this is the simplest method and is based on the principle of filtration; it involves conveying the waste water through a filter that removes the solid particles suspended in the water. These are manually operated plants that can be used to treat industrial waste water as needed. This plant is able to purify technological waste water produced by tumbling processes thanks to a de-emulsifier/adsorbent product that absorbs pollutants like suspended substances, turbidity, dyes, surfactants, mineral oils, heavy metals, organic solvents, etc... The purification process is discontinuous (in batches) and consists in treating the waste water by means of a flocculation and decanting process. The water that needs to be treated is mixed with the de-emulsifier/adsorbent product that causes the formation of floccules, which absorb most of the impurities contained in the water dragging them down towards the bottom of the decanter. WATER PURIFICATION PLANTS Novagum . produces a filtration plant with interchangeable bags called DEC 2. Purification is carried out by filtering the water, that is by conveying the waste water though special filters (bags) that remove the solid particles suspended in the water. The bag decanter manufactured by Novagum . is designed to purify the waste water produced by small- and medium-sized plants. Its function is to separate the solid particles suspended in the water by means of a decanting and filtering process. This system simplifies the storage of slugs and their dehydration prior to disposal. Consequently, it solves in part the issue of re-using water as it enables customers to re-use the same water for several cycles.