LOCALadk Magazine
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Summer 2014 61 LOCALadk The Digester A Sustainable Solution to Waste Management in the North Elba Region By Tammy Morgan In 1998 the last active landfill in the Adirondacks was shut down. Since that time, communities in the park have been hauling wastes great distances and paying other towns and counties to take their garbage. This "out of sight, out of mind" approach to garbage may work in the short term, but town managers need to ask the question, "How sustainable is this?" With rising fuel costs and decreasing landfill space, trucking wastes to distant landfills is economically and environmentally unstable. In addition to the fossil fuels used to transport wastes, the environmental impact of landfills includes loss of habitat and farmland, potential groundwater impacts, and increases in greenhouse gases. It is time to start recognizing garbage as the valuable commodity it is, and the town of North Elba is doing just that. The town board is developing an organic waste recycling program that will turn food wastes into renewable energy and fertilizers, and the plan is simple. Participating businesses and institutions in the region will have a single separate container for food and organic wastes. Casella, a partner on the project, will bring the organic wastes to the North Elba transfer station in Lake Placid, where it will be fed into an anaerobic digester. The digester contains bacteria that convert organic matter into biogas and a liquid slurry called digestate. The biogas will be burned in a generator producing electricity for the electric grid. The liquid portion of the digestate will be used to irrigate athletic fields surrounding the transfer station, and the solid portion will be converted to compost available for sale on site. Funding for the project was made available through the Regional Economic Development Council as part of New York State Energy Research and Development Authority, NYSERDA's Cleaner Greener Communities program. The Town of North Elba worked collaboratively with Essex County and the Adirondack North Country Association (ANCA) to secure the $1 million grant to make this vision a reality. The anticipated completion date is June 2015. Estimates from a 2012 feasibility study predict that this project will annually divert 900 tons of wastes from landfills, create enough electricity to power close to 30 homes, produce $6000 worth of compost, decrease water and fertilizers needed for athletic fields, and save the region money on tipping and transportation fees. Building resilient communities requires new ways of thinking about old problems. Sustainable solutions like this one are good for people, local economies, and the environment now and for generations to come. Maintaining the digester will require skilled labor and will help stimulate the local economy. This is a multi-faceted community based project that is bringing people and partners together; it is the first of its kind in the U.S. Generations have been putting environmental problems to the side and thinking of linear solutions to problems. This project looks at the whole food waste system and provides a sustainable solution to our waste management problems. V i s i t To d a y t u p p e r - l a k e . c o m t u p p e r l a k e n y. g o v ( 5 1 8 ) 3 5 9 - 3 3 4 1 Whether you're here for a weekend or a life me, you'll enjoy your stay. for more information visit mylonglake.com organic material Organic materials are the "input" or "feedstock" for a biogas system. Some organic materials will digest more readily than others. Restaurant fats, oils and grease; animal manures; wastewater solids; food scraps; and by-products from food and beverage production are some of the most commonly-digested materials. A single anaerobic digester may be built for a single material or a combination of them. Organic material is broken down in a digester Processed biogas is distributed and used Raw biogas is processed Organic material is delivered to the digester system This may include animal manure, food scraps, agricultural residues, or wastewater solids. The digester uses a natural biological process under controlled conditions to break down organic material into products for beneficial use or disposal. The gas may be used to produce heat, electricity, vehicle fuel or injected into natural gas pipelines. Typically, water, carbon dioxide and other trace compounds are removed, depending on the end use, leaving mostly methane. Digested material is processed and distributed Solids and liquids from the digester may be used to produce marketable products, like fertilizer, compost, soil amendments or animal bedding. Some biogas can be used to heat the digester. Digested material may be returned for livestock, agricultural and gardening uses. Liquids and solids may be separated. the digester An anaerobic digester is one or more airtight tanks that can be equipped for mixing and warming organic material. Naturally occurring microorganisms thrive in the zero-oxygen environment and break down (digest) organic matter into usable products such as biogas and digested materials. The system will continuously produce biogas and digested material as long as the supply of organic material is continuous, and the microorganisms inside the system remain alive. biogas processing Biogas is mostly methane, the primary component of natural gas, and carbon dioxide, plus water vapor, and other trace compounds (e.g. siloxanes and hydrogen sulfide). Biogas can replace natural gas in almost any application, but first it must be processed to remove non-methane compounds. The level of processing varies depending on the final application. biogas distribution Processed biogas, often called "biomethane" or "renewable natural gas," can be used the same way you use fossil natural gas: to produce heat, electricity, or vehicle fuel, or to inject into natural gas pipelines. The decision to choose one use over another is largely driven by local markets. digested material In addition to biogas, digesters produce solid and liquid digested material, containing valuable nutrients (nitrogen, phosphorus and potassium) and organic carbon. Typically, raw digested material, or "digestate," is processed into a wide variety of products like fertilizer, compost, soil amendments, or animal bedding, depending on the initial feedstock and local markets. These "co- products" can be sold to agricultural, commercial and residential customers. fertilizer SOLIDS LIQUIDS BIOGAS DIGESTED MATERIAL Image courtesy American Biogas Council