Experts discuss the benefits and challenges facing AD project development.
Anaerobic digestion (AD) projects continue to develop in the United States and Europe. Understanding how to effectively move those projects forward was the subject of a session held during WasteExpo 2014 in Atlanta in late April.
Michelle Spruth, a project manager in Illinois for Netherlands-based CB&I, shared the firm’s experience with implementing a dry AD facility at a landfill in Packington, U.K. The landfill there only had about 400,000 tons or about 1.5 years of capacity left.
“Everyone wanted us to finish up landfilling and get out,” said Spruth. “Constructing a new waste treatment facility was a big of a blow to them.”
CB&I put together a communications plan and looked at more than 200 sites before deciding to locate the AD facility at the existing landfill. Austria-based Strabag was selected as the AD technology vendor on the project.
Spruth detailed “Lessons learned” on the project, which included engaging regulators and stakeholders early; flexibility in design to accommodate local needs; and phasing of operation with other operations or surroundings.
“You have to plan for the long and short-term,” she advised.
Kyle Goehring, regional sales manager for Eisenmann Corp., Crystal Lake, Illinois, shared how several large players in the private industry have waste reduction goals and places like Connecticut, Vermont, Massachusetts and New York City have policies aimed at waste reduction.
He also showed that while 28 percent of municipal solid waste is made up of food waste and yard waste, only 1.6 percent of food waste is being diverted. For food processors and restaurants, however, an even larger percentage of the waste stream is made up of food. According to Goehring, the Hamilton, Ontario-based restaurant chain Tim Horton’s conducted a waste audit and determined 69 percent of its waste was organic.
Eisenmann’s AD technology is a two-stage digester process, Goehring described. The company is currently working on project for CR&R in Perris, California, to process food and yard waste from the waste company’s 2.5 million customers. It is being built to produce 1 million diesel gallon equivalents (DGE’s) of compressed natural gas per year.
The Eisenmann digesters can accept between 0 and 50 percent solids. “Our technology really worked for them because it’s flexible,” said Goehring.
Marc Rogoff of Long Beach, California-based SCS Engineers, talked about AD as a “technology whose time has come.”
He offered 10 key feasibility questions that those considering AD should ask. They are:
- Does the technology work?
- What is the strength of the company?
- Does the technology fit with the current solid waste program?
- Can you provide waste supply?
- What are the project’s siting needs?
- What kind of permits will be needed?
- Are markets available for products and energy?
- Financing risks?
- What are the costs?
- What if the project fails?
He said areas where tipping fees are between $70 and $100 can consider treatment technologies such as AD for their waste, but added compost and digestate revenues don’t exist everywhere.
WasteExpo 2014 was April 30 to May 1 at the Georgia World Congress Center in Atlanta.