Optimization of the process of membrane separation of MSW landfill leachate with a high concentration of hardness saltsOptimization of the process of membrane separation of MSW landfill leachate with a high concentration of hardness salts

Summary

The aspects of optimizing the process of reverse osmosis membrane separation of the leachate of a municipal solid waste landfill with a high concentration of hardness salts is considered. The research was carried out in an experimental two-stage reverse osmosis unit. To study possible increasing the efficiency of the membrane reverse osmosis separation of the leachate and, in particular, of the membrane flux, various inhibitors of sediment formation were added to the feed clarified percolating water (before the membrane separation): Avista Vitec 3000, Clarofos 381, and sodium tripolyphosphate. Percolating water of the Mar’inskii solid waste landfill (Vladimir region) with a high concentration of hardness salts was used as a researchable aqueous solution. Based on the results of the executed studies, the effect of various inhibitors of sediment formation on the process of membrane reverse osmosis separation was estimated in terms of the membrane flux. The positive effect on membrane separation of the inhibitors of the sediment formation of hardness salts on the membrane surface added into the feed clarified leachate of the solid waste landfill has been proven. The best results in increasing the membrane flux during the purification of clarified percolating water were obtained with the use of the Avista Vitec 3000 inhibitor. The executed studies have shown that while choosing a sediment formation inhibitor, the specific composition of the feed water, the operating mode of the membrane equipment and the special requirements of the purification technology should be taken into account.

Key words

high concentrated wastewater , membrane separation , scaling inhibitors , two-stage reverse osmosis unit , hardness salts , membrane flux , concentration grade

Estimation of the effectiveness of using sodium-cation exchange resins in the process of water softening for the operation of heat producing plants

Summary

The results of estimating the effectiveness of removing hardness salts from water by the ion exchange method using various sodium-cation exchange resins with the aim of using softened water to feed heat producing plants are presented. The studies were carried out in an ion exchange pilot plant using a single-stage flow scheme of sodium cationization in laminar conditions. The experiments involved determining the dependence of the softening efficiency on the water flow rate until the resource exhaustion of each of the resins with the subsequent regeneration and repeated studies of the effectiveness at different flow rates. It was established that sodium-cation resins provided for a high degree of removing hardness salts. At the same time, higher results in terms of the softening efficiency and degree of regeneration were obtained with Purolite C100E and Tokem-150 resins. Based on the results of the studies using these trademarks of resin for water softening as part of multi-stage water treatment plants at thermal power plants and boiler houses was proposed.

Key words

ion exchange , regeneration , water softening , hardness salts , heat producing plant , sodium-cation exchange resins