Study of the processes of colored solutions purification using inorganic coagulants and natural floculant

Today the problem of purification of domestic and industrial wastewater from a variety of organic and inorganic pollutants is one of the most important and topical issues in the world. The further harmonious existence of all aquatic ecosystems depends on a successful solution of this problem. In the process of work, studies on the analysis of existing methods of sewage treatment, painted with different types of dyes, and the search for efficient ways to improve them have been carried out. The coagulation process using coagulants in combination with natural and artificial flocculants is one of the effective ways of treating colored sewage. The coagulation process is usually carried out using coagulants based on aluminum and iron salts that are capable of hydrolyzing in water to form various coagulation structures with high adsorption and adhesion properties. The addition of flocculants, even in small amounts, besides conventional coagulants, promotes the faster formation of flakes, sedimentation and filtration, stabilizes the process of purification, improves the quality and efficiency of the equipment operation. At the Department of Chemical Technologies and Water Treatment, the research of the determination of the optimal dosage of coagulants based on aluminum (Al₂(SO₄)₃ • 18H₂O, ALS) and iron (PIX-318) to purify colored model solutions that are similar to the sewage of Ukrainian coloring companies has been conducted. Natural amino polysaccharide – chitosan, which is offered as the effective flocculant, has been used in combination with inorganic coagulants. Being a weak cationic flocculant, chitosan has an increased efficacy of protein sedimentation compared with classical flocculants. In the process of purification of model solutions, the optimal dosages of coagulants and the flocculant – chitosan have been determined using the Jar-test method. The degree of purification of colored model solutions, from the concentrations of added coagulants and flocculant, as well as the degree of water pollution and the duration of deposition have been established. Increasing the duration of the sedimentation process allows to increase the degree of purification of colored model solutions. The advantages and disadvantages of different properties of coagulants are identified and recommendations are developed to improve the efficiency of the use of the coagulation process of purification