Cold Climate Operation

Storage is generally not provided for SAT even where cold winters would limit operation of SR or OF systems (Reed et al., 1995). Proper thermal protection is needed for pumps, piping, and valves (Reed and Crites, 1984). Wastewater can continue to be land applied in SAT basins throughout subfreezing weather provided the soil profile does not freeze with moisture in it. Approaches that can be used to avoid critical ice formation include:

1. Design of one basin with excess freeboard to accept continuous loading for up to 2 or 3 weeks during extreme conditions; this basin would then be rested for an extended period during warmer weather and the basin surface scarified.

2. Ridge and furrow surface application combined with a floating ice cover; the ice gives thermal protection to the soil and is supported on the ridges as wastewater infiltrates in the flowing furrows.

3. Use of snow fences to retain snow on the basins to insulate the soil.

4. Use of wastewater (perhaps bypassed from the headworks) with minimal preapplication treatment to retain the available heat in the wastewater.

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