Cold climate facultative lagoons
Facultative lagoons are of great importance to small communities of Alaska and northern Canada. Severe climatological conditions along with seriously impeded economic development have dramatically reduced the viable alternatives available for wastewater treatment. Design engineers face almost formidable constraints when attempting to produce “secondary” effluents for these communities. Because of permafrost, the absence of electrical power, average annual temperatures as low as −12 °C (10°F), the lack of skilled manpower, and other operating restrictions, lagoons can be of strategic importance to water quality protection in these locations.The use of “southern” technology may not be applicable under arctic–subarctic conditions and even if it is applicable it must be used with considerable reservation. This paper reviews the use of facultative lagoons in cold climate areas and addresses issues of design parameters, economics, and the system's ability to meet wastewater treatment regulations and water quality standards. Consideration of factors influenced by temperature including psychrophilic organisms and ice cover are reviewed in this discussion along with a “common sense” approach to design. Key words: lagoons, cold, permafrost, wastewater, design, BOD, ponds, facultative, algae, northern, ice, anaerobic, kinetics, arctic.