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UDC 628.1/.2(98)
Kofman V. Ya.
Water supply and wastewater disposal in the Arctic Region:
advanced technical soltions (a review)
Summary
In Canada wastewater treatment technology has been developed for small isolated arctic communities based on the effective biodegradation of organic carbon using a combination of anaerobic methanogenic and microbial bioelectrochemical processes that provide for biomethane generation. Microbial electrochemical degradation is executed in a membrane-free flow-type reactor with a bioanode and a biocathode operating at a voltage below the threshold of water electrolysis. In laboratory-based experiments in a wide range of mesophilic and psychrophilic temperatures (5–23 °C) a high efficiency of reducing BOD5 (90–97%) was achieved with a residual content of less than 7 mg/l. Energy consumption is 0.6 kWh/kg COD. Low energy consumption along with the production of biomethane ensures the operation of the reactor in the mode of power generation. For the conditions of Greenland a scheme of wastewater disinfection involving chemical coagulation and addition of peracetic acid, and/or ultraviolet irradiation was developed. Complete inactivation of Escherichia coli is achieved with the combined use of ultraviolet radiation (2.1 kWh/m3) and peracetic acid. Preliminary coagulation is an essential prerequisite for the effective inactivation of microorganisms. In the United States a closed water treatment scheme based on the peroxone process with reuse of water for drinking purposes has been proposed for the city of Fairbanks (Alaska). The big advantage of the closed-loop scheme is 85% conservation of the water in the system while preserving the thermal energy obtained from different water heaters. As a result the purified warm water is returned to the consumer; while less energy is required for its additional heating. In addition, the mineralization of organic substances in the oxidation process ensures the achievement of 0.7 mg/l residual COD.
Key words
wastewater , water disinfection , water treatment , ultraviolet irradiation , water reuse , the Arctic Region , preliminary coagulation , peracetic acid , peroxone process , heat energy of water , anaerobic methanogenic process , microbial electrochemical process
