Solid Waste Disposal

It is said that if you get a group of Alaskans or northern Canadians together for an evening's conversation, the talk will, sooner or later, turn to sewage.

Sewage is a topic dear to the northerner's heart; it, like the weather, is something that concerns everyone and gives each at least occasional trouble. Low ground temperatures, water-impervious soils, deep seasonal freezing and permafrost can act individually or collectively to make sewage disposal a messy problem in both rural and urban areas.

One reason sewage gives us so much problem is that we insist upon thinking that sewers and water supplies must always go together. Worse yet, we are inclined to believe that the only way to handle sewage is in a water solution. There are other ways, lecturer Sim Van der Ryne told attendees of the First Alaska Alternative Energy Conference held in Anchorage, November 9-11, 1979. In a conference workshop he held on waste disposal, Van der Ryne described water-free techniques that can be used to safely dispose of solid human waste. The concept is particularly attractive because scarce water and impervious soil are accepted facts of life in many arctic and subarctic localities.

The idea is to retain human fecal matter in vented but otherwise tight containers to which carbon is added regularly. A few handfuls of sawdust, leaves or moss added each day provide the carbon necessary to curtail odor and, later, to promote effective composting.

Holding compartments can be 55-gallon drums or other portable but airtight containers. Three or four drums provides enough volume to carry a family of four over winter.

When summer comes the next step is to place the capped containers in a greenhouse-like room for a month or so where solar energy can heat the material to temperatures of 180-200°F (68-80°C). Thorough heating to at least 160°F is necessary to kill parasites and disease carriers. It is then possible to safely compost the residue to obtain nutrients for gardens or other plants. However, direct use on leaf crops to be eaten is not recommended.

In addition to being a safe way to handle solid human waste, the waterless method system described by Van der Ryne has the potential for low cost and reliability. Those northern communities that have had experiences with high-cost and failure-prone sewage systems employing water can especially appreciate these qualities.