Linden Hills trash now has a higher purpose than winding up in a landfill. In the first month of its Source Separated Organics (SSO) collections program (Sept 15 – Oct 13), Linden Hills sent 17 tons of food waste to a processing facility to be turned into compost. Residents and local businesses are learning to separate out biodegradable materials from other waste, sending organic trash to a different destiny as future food and flowers.
Diverting organics for recycling reduces the flow of waste to landfills, reduces the city’s carbon footprint, and yields a valuable end product – a soil amendment that replenishes soil nutrients and helps soil hold moisture, according to Susan Young, Director of Solid Waste and Recycling for the City of Minneapolis
“SSO are considered to be the largest component of the waste stream that can be diverted for a ‘recycling’ (compost) option and so aid the city in meeting its 50% waste reduction goals,” says Young. “Depending on demographic makeup, 30-40% of Minneapolis garbage by weight is SSO.”
Enter the Linden Hills Power and Light Source Separated Organics program. Residents separate their trash at the source–their homes. The home waste sorting process is easy, requiring only another small bin in the kitchen to collect food waste, and paper bags or newspapers to wrap it in. Once a week, residents put their green organics cart out next to their recycling bin for curbside pick-up.
SSOs include food scraps, non-recyclable paper such as pizza boxes and paper towels, and even vacuum cleaner bags and dryer lint.
“Ask ‘What would a bug eat?” said Felicity Britton, Executive Director of Linden Hills Power and Light. “Plastics, no. Anything natural, yes. It’s only a matter of sorting waste into two bins. And it’s so good for the environment!”
For further information on setting up a kitchen composting, or how to identify compostable items, see Linden Hills Power and Light.
Organic refuse is brought to the Hennepin County Transfer Station, and sent on to one of two resource recovery centers where it is shredded and placed in plastic covered windrows. The waste is aerated, and closely monitored for nitrogen content and other nutrients. Inside the windrows, aerobic bacteria cause it to self-heat to high enough temperatures to kill pathogens and break down into a more usable product, taking about 18 months to turn into finished compost. The resulting material looks like dirt, and is used to green the verges of highways, or as a soil amendment for landscaping. According to Young, the Department of Solid Waste and Recycling is looking for a viable way to disburse compost to residents for use in their gardens.
Diverting waste to compost saves money. Tipping solid waste costs $38 per ton – and the weight of diverted materials in an SSO program can be considerable, as organics tend to be the heavier waste like watermelon peels, rather than lightweight refuse like plastic packaging. The “tipping fee” for organic waste is only $15 per ton “tipped” (dumped) at the Transfer Station. That means diverting waste to organics composting decreases Minneapolis expenditures for waste disposal.
Young estimates 90% of the city’s solid waste stream, by weight, could be shifted to SSO organics waste tipping at $15 a ton. That would leave only 10% of the city’s waste tipping at $38, creating a huge savings.
Businesses also can benefit from the $15 tipping fee. “The owner of Great Harvest Bread believed the bakery generated little waste, but he’s now saving 50% on his garbage fees,” said Felicity Britton. “Separating out organics could save a large restaurant a ton of money.”
So how did Linden Hills begin this program? “Our community wanted to take steps against global warming, and once our light bulbs were changed to CFLs, what could we do?” said Britton. “Our mission is to reduce our global warming footprint. People were flocking to take some sort of action, and someone asked – why don’t we get Linden Hills off the grid?”
The Minneapolis Pollution Control Agency and the Minneapolis Department of Commerce funded a feasibility study of a community-scale anaerobic digester using food waste to produce renewable energy. Initial studies indicated that power generation from a five-ton-a-week, neighborhood-scale anaerobic digester would not prove profitable, but the process of study resulted in the Linden Hills Source Separated Organics program. With the recent news that the University of Florida has developed a micro-digester facility which uses technology developed for extended space flight, Linden Hills is again considering the use of waste to generate power for heating or generating electricity.
The Source Separated Organics program is popular among Linden Hills residents, with Compost Captains on every block distributing information, and 1,004 out of 2,526 eligible households and several businesses participating.
Compost captains cover most blocks in Linden Hills. For a map, download the PDF.
Britton was floored by the number of people attending the first Compost Captain event on a cold night in February. Sixty people showed up to learn how to help educate their neighbors, and that number has doubled since then.
Marybeth Colbert attended that first meeting to become a Compost Captain. “It was fun,” Colbert said. “There was so much interest, so many people anticipating the project. It was full of energy. Sixteen out of 27 houses on my block are now doing it.”
Britton would like to see this program expand to local schools. The Minneapolis School District is supportive of the concept, but lacks funding for the upfront cost of bags and bins to get the system in place. Linden Hills Power and Light is working with local schools to help them obtain grants and other start-up funding to make participation possible.
The Linden Hills SSO pilot program will provide critical information for the Department of Public Works on what percentage of refuse residents are actually able to divert, along with the cost effectiveness of the program, and willingness of households to participate. Information gathered will inform City decisions on similar project roll-outs in other neighborhoods.
Karen Engelson is a Twin Cities writer interested in environmental issues.