The data of studies on the effectiveness of anionic and cationic flocculants used for reagent treatment of Sura River water during a flood together with aluminum sulfate coagulant are presented. In experiments, 2 anionic polyelectrolytes (K-4043 and PAA) and 3 cationic ones (VPK-402, K-6735 and K-6841) were studied, the flocculating ability of which was assessed by turbidity, permanganate oxidizability, residual concentration of aluminum ions and the color of water after two-stage purification by settling and filtration. The most significant results in the quality of natural water purification from organic and mineral impurities were obtained using cationic polyelectrolytes with a high molecular weight (about 107), which reduced the required coagulant doses by 33% compared with experiments using aluminum sulfate and polyacrylamide. The results of the laboratory studies presented in the article can be used at water treatment plants for river water treatment during the flood period.

Keywords: surface source water, coagulation, anionic and cationic flocculants, sedimentation, filtration, purification efficiency

Analytical dependences have been obtained that make it possible to assess the influence of various factors on the degree of enlargement of microflakes formed in the thickness of the coarse-grained load after the introduction of coagulant. To assess the intensity of the coagulation process, the values of the mixing rate gradient were obtained depending on the filtration rate of coagulated water in a coarse-grained load. Graphs are also provided that establish the dependence of the mixing rate gradient depending on the filtration rate of coagulated water in a coarse-grained load. A scheme of coagulation treatment of natural water using a contact chamber with coarse-grained loading and receiving concentrated coagulation is proposed, which is recommended for intensifying the operation of typical hydraulic mixers of water treatment plants and reducing the required doses of coagulant.

Keywords: contact coagulation, natural water, mixing devices, mixing rate gradient, filtration rate

The article provides an analysis of technological schemes for the reuse of contaminated water obtained after washing the rapid filters of water treatment plants. The advantages and disadvantages of existing options for reuse and disposal of purified and untreated wash water are shown. A new water treatment technology has been proposed, which involves pre-treatment of wash water with an organic coagulant, followed by mixing it with river water and subsequent reagent purification of the resulting mixture by settling and filtration.

Keywords: water treatment, filter wash water, coagulation, aluminum sulfate, organic coagulant, clarification

Information about authors of issue №2 (2008)

Keywords: authors