Pilot testing the technology of low-turbid colored water conditioning in the process of two-stage filtration

Summary

The results of the pilot tests of the technology of low-turbid colored water conditioning by two-stage filtration are presented. The tests were carried out to specify the parameters of the technology being developed and to determine the effectiveness of water purification of the Zeya River (Amur Region) with a view to its use in domestic and industrial water supply of the designed industrial facility. During the test period the river water was characterized by low temperature (3.5–7.5 °С), low pH values (6.5–6.7) and alkalinity (0.4–0.5 mg-eq/dm³) with color up to 80 degrees. To specify the chemical dosages preliminary (laboratory) tests were carried out. It was established that the treatment of river water with sodium hypochlorite provided for a noticeable bleaching effect – up to 40%. However, increasing the oxidizer dosage to more than 10 g/m³ is ineffective. At the specified river water color the dosage of chemical can be set within 5–7 g/m³. Owing to low alkalinity values it is recommended to alkalize water with soda ash at an optimal dose of 6 g/m³. According to the results of the test chemical treatment of water the preference was given to Aqua-Aurat™30 coagulant at doses of 35–40 g/m³. By comparison of the flocculants of Praestol group, Praestol 650TR showed the best results at doses of 0.1–0.15 g/m³. Pilot tests of purifying Zeya river water proved the high efficiency of the two-stage filtration technology (contact prefilter + rapid filter). The use of Aqua-Aurat™30 coagulant in combination with Praestol 650TR flocculant ensured the standard quality of drinking water, as well as the quality required for industrial water supply of the designed industrial facility.

Key words

sodium hypochlorite , water treatment , coagulant , flocculant , low-turbid colored river water , two-stage clarification , soda ash