Gravity sewer collection system design and operational challenges: A case study from northwestern Alaska.

摘要

The successful design of gravity sewers in permafrost depends on having adequate daily wastewater flows of sufficient temperature at the upper ends of the sewer system to resist freezing and fouling with sediment. This report is a case study of heat loss and temperature drop for a low flow gravity sewer line. Use of Water flushing, electric heat trace, or periodic thawing are methods for adding heat to low flow sewer lines, and the report evaluates the cost of those heat addition options. The report analyzes values of soil temperature over the year, flow rates per capita, and thermal resistance of arctic pipe. Field soil temperatures and water usage are compared to those predicted for the case study. The measurements made were done using a thermistor string, a thermistor with data logger, and sewage pumping station hour meters.