Composting at the Wastewater Treatment Plant in Fairbanks, Alaska, 2008
In Fairbanks, Alaska, the wastewater treatment plant is owned and operated by Golden Heart Utilities. In 1998, approximately 630 wet tons of biosolids are processed each month. The waste is generated and collected from College Utilities, the Fairbanks North Star Borough pumping companies, the City of Fairbanks, Fort Wainwright and University of Alaska Fairbanks. This waste must be processed in a manner which fits the requirements of the Alaska Department of Environmental Conservation and the Environmental Protection Agency.
Who Initiated Program:
The wastewater treatment plant was owned by the Fairbanks Municipal Utilities System when the project was initiated, but now it is owned and run by the Golden Heart Utilities.
One part of processed sludge is mixed with 2 and a half parts large woodchips with a mixing truck. A front end loader is used to pile the mixture in aerated static piles. The piles are 100 feet long, 160 feet wide and 12 feet high. The site has room for 6 piles this size. The air is pushed into the pile (referred to as positive air) with a piping and blower system. The blower is on a timing relay.
The temperature is monitored once a day. The required regulatory temperature to reach is 55 degrees C. for 3 days and 40 degrees C. for 2 weeks. However, temperatures as high as 80 degrees have been reached.
The mixture was composted for 2 to 6 months. It was then screened with an EX TEC screen. Then piled and cured for 6 to 8 months. It is only required to cure for 30 days.
The finished compost has an earthy smell and makes an excellent soil amendment and will be available to the public for a fee in the 1999 growing season.
In 1999, a large quantity of finished compost will be available for sale to home gardeners, landscapers, and agriculturists.
The compost process has worked well. All through the winter of 1998 the composting continued. The lowest ambient temperature measured that winter was 35 degrees F. below zero.
Problems and/or Suggestion
It is currently an expensive process and the Golden Heart Utilities is working on finding ways to reduce the cost of composting.
For More Information:
For further information about the project or to purchase compost contact:
Golden Heart Utilities