RECYCLED WATER TREATMENT OPTIMIZATION AT A PLASTICS RECYCLING PLANT

Relevance.One of the most pressing global issues is plastic waste recycling, which is impossible without high-quality thorough washing of the waste plastic. Currently, the issues of recycling plastic products are especially acute. As a result, in the enterprises focused on the recycling of plastics, special attention is paid to the preparation of raw materials. The presence of even small amounts of contaminants leads to a deterioration in the quality indicators of secondary polymers (bulk density, strength, flowability) obtained in the form of fleck or regranulate. Coagulants and flocculants are used to remove sparingly soluble impurities of various natures. The absence of a unified theory of the use of coagulating reagents and the optimal operating parameters of secondary water treatment entails excessive consumption of reagents, which is both technologically and economically unprofitable. At the same time, at the overwhelming majority of enterprises, the choice of regime parameters for water treatment (concentration of reagents, temperature, coagulation time) is carried out purely empirically. Precise selection of the reagent quantity makes it possible to maximize the efficiency of water treatment and meet the requirements of standards for their residual concentration in recycled water. The problem of optimizing water treatment is relevant, since the effectiveness of the use of coagulants and flocculants depends on a large number of factors. At the same time, the use of probabilisticdeterministic planning makes it possible to scientifically optimize the water purification and thereby eliminate the overspending of reagents. The propose of the study is to optimize the operating parameters for recycled water purification at an enterprise for recycling plastics. Methods: sedimentation analysis, method of probabilistic-deterministic planning. Result. The processes of coagulation and flocculation of contaminants in recycled water of an enterprise for recycling plastics have been studied. Based on the use of the principles of probabilistic-deterministic planning of the experiment, a cycle of studies was carried out aimed at establishing the regimes of water purification of recycled water. The kinetic dependence of sedimentation in the presence of a coagulant aluminum sulfate and a high-molecular-weight cationic low-charge flocculant was established. The optimal modes of coagulation: costs of coagulant and flocculant, temperature, duration of coagulation, was established.