Pre-project in-process testing river water purification in the Arctic Circle

Summary

The results of pre-project in-process testing purification of water of the Vary-Khadyta River, the source of drinking and domestic water supply for the village of Yar-Sale (Yamal-Nenets Autonomous Okrug), are presented. Throughout the year the permissible concentration of iron, manganese, suspended solids and compounds in the river water that cause the water color is exceeded. Low temperatures, alkalinity and salinity result in the low level of water stability (Langelier index from –3.8 to –1.1 points). Water treatment facilities in Yar-Sale village (WTF-50) do not provide for the standard quality of purified water. This due to both incorrect water treatment technology that involves only filtration for clarification, and an incomplete set of chemicals required to produce drinking water. During the upgrade of the treatment facilities replacing the technology with the traditional clarification flow scheme (sedimentation – filtration) because of the periodic use of high doses of coagulant, as well as supplementing the chemical treatment with processes of alkalization and oxidation of the river water manganese with potassium permanganate was proposed. To assign the design modes of chemical water treatment, in-process tests were carried out under the conditions of the WTF of Yar-Sale village. For clarification and color removal, the chemicals used at the WTF of Yar-Sale village were applied (POHA «Aqua-Aurat-30^TM» coagulant, flocculant Praestol 2530). It is shown that using only these chemicals did not provide for the standard quality of drinking water. To enhance the efficiency of purification, it is proposed to carry out chemical treatment in two stages: upstream the sedimentation tanks – alkalization, coagulation and flocculation, then upstream the filters – additional alkalization, oxidation of manganese with potassium permanganate and additional flocculation. The operational doses of chemicals were determined, that ensure the production of stable drinking water meeting the requirements of the current regulatory documents. Based on the test results obtained, a standard operating procedure for designing the upgrade of the WTF-50 of Yar-Sale village was developed.

Key words

deferrization , potassium permanganate , demanganization , river water , stabilization treatment , soda ash , color removal , «Aqua-Aurat-30тм» , Praestol 2530