Developing a sustainable sewage treatment system for rural Alaskan villages

Project Overview

Photograph showing the small rural village of Nunapitchuk Alaska — Image courtesy of Alaska Department of Environmental Conservation, Village Safe Water Program.

There are currently some 3,300 homes across 30 villages in rural Alaska that that lack water and sewer services, including flush toilets. Managing human waste in those communities poses significant public health and environmental challenges.

Researchers with EPA’s Office of Research and Development have teamed up with the Agency’s Region 10 Office (serving Alaska, Idaho, Oregon, Washington, and 271 Tribal Nations), the Alaska Department of Environmental Conservation, the U.S. National Renewable Energy Laboratory, and other partners to find solutions.

In one innovative project, researchers are exploring the development of a solar augmented anaerobic digester to turn fecal matter, along with cardboard and other waste products from the community, into energy in the form of biomethane gas. The goal is to find an optimum waste stream mixture and methane yield under laboratory conditions, then combine the findings with available climate data (temperature and daily solar radiation) to determine how large a solar heating system would be needed to keep an anaerobic digester running in the cool Alaskan climate.

The researchers aim to answer three primary questions:

How much methane can be produced?
Can solar inputs provide the heat energy required to make anaerobic treatment feasible in arctic Alaska?
What are the optimum and minimal sizes of a community to sustainably operate an anaerobic digester?

Partners

EPA Research
EPA Region 10
Alaska Water and Sewer Challenge (Alaska Department of Environmental Conservation)

Publications

Journal Article: An evaluation of solar thermal heating to support a freeze-thaw anaerobic digestion system for human waste treatment in subarctic environments

In Alaskan villages, freezing temperatures and remote locations issues make installation and operation of typical wastewater treatment systems impossible. This manuscript investigates the technical feasibility of anaerobic digestion of synthetic human feces after freezing. Multiple freezing conditions and incubation temperatures were investigated. Following positive results (methane generation) from the laboratory experiments, thermal modeling was conducted to estimate heat energy demands for hypothetical anaerobic digesters located in several Alaskan towns/villages. Solar radiation and air temperature data from other sources were used to perform the modeling assessment. Academic audiences would be interested to understand the resiliency of anaerobic microbes. Government entities or public groups may be interested in the prospect of anaerobic digestion in cold climates but many technical and social challenges for implementing a system need to be further addressed.

Learn More

Please check back periodically to learn about partnership opportunities, upcoming webinars, and research results.

Technical Contacts

Max Krause, EPA Office of Research and Development (Krause.max@epa.gov)
Margaret McCauley, EPA Region 10 (McCauley.Margaret@epa.gov)