Industrial horizontal intensified clarifier for water
softening/decarbonization by liming

Summary

Chemical softening methods have been widely used in the water treatment practice. As shown in the previous review, the chemistry of the process has remained unchanged over the past 100 years; however, the instrumentation of the process has changed. This equates to significantly increase the capacity and efficiency of the devices. Research work has been carried out on designing domestic intensified apparatus for softening/decarbonization of water by liming; and their introduction into industrial practice has started. Studies of the developed version of the multi-chamber horizontal clarifier with liming of Aquafloc type were carried out. The boundary parameters of the process of water liming with coagulation with iron salts were determined. It was established that the improved mixing, acceleration of chemical reactions and recirculation of carbonate sludge (seed) provide for the optimization of the sedimentation process to reduce the coagulant consumption and significantly improve the sludge characteristics. Essential advantages of the clarifier are as follows: smaller dimensions and metal consumption compared to classical clarifiers, as well as a short time to reach the operating mode. Thereby, an Aquafloc clarifier can be delivered to the site ready assembled, ready-to-use and with anti-corrosion protection that significantly reduces the time and cost of assembling at the facility. The concentration of dry matter in sludge reaches 8%. In comparison with the existing VTI-630 clarifiers, Aquafloc clarifier showed similar results in terms of chemical parameters and the best in terms of the concentration of suspended solids. In terms of water consumption for own needs, the clarifier turned out to be at the level of VTI apparatus that have a total blowdown volume of 2–4%.

Key words

coagulation , suspended layer , hardness , enhanced treatment , water , mixing , chemical water softening , liming , horizontal clarifier

Designing horizontal clarifiers and studying the efficiency of the water liming process

Summary

Chemical softening methods have been widely used in water treatment. As shown in the previous review, the chemistry of the process has remained unchanged for the past 100 years; however, the instrumentation has changed. This provides for increasing significantly the capacity of the devices and their efficiency. Mediana-Filter R&P JSC carried out research on the development of domestic intensified devices. The studies were carried out in a small-scale laboratory three-chambered horizontal clarifier with a lamellar settling tank and in a pilot clarifier with a variable chamber volume. The optimal procedure of introducing chemicals, the minimum and optimal residence time of water in the clarifier chambers have been determined. The achieved rate of the upward flow in the zone of clarification in the boundary conditions was 25 m/h. The data obtained was taken as a basis ground for designing industrial apparatuses.

Key words

suspended layer , hardness , water , mixing , chemical water softening , liming , horizontal clarifier