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Exploring the benefits of composting a correctional facility's food waste.

Faced with escalating waste disposal costs, many correctional facility food service operations now regularly recycle plastic, glass, aluminum and tin, as well as corrugated cardboard and clean paper. Inaddition, a growing number of facilities have taken this concept a step further and are recycling food scraps and soiled paper such as napkins through composting.

Composting is a natural process that converts organic waste matter into humus, a valuable soil product which can be sold or kept on the institution's grounds for agricultural uses.

By composting food and paper waste instead of sending it to a landfill or incinerator, an institution can significantly reduce its long-term waste disposal budget while contributing to recycling and diversion goals. Since food waste is wet, it often causes problems at landfills by contaminating ground and surface water. For most incinerators, food waste is so wet that it absorbs heat and thus detracts from the incinerator's efficiency.

Food waste weighs about 800 pounds per cubic yard and may represent up to 30 percent of the total weight of an institution's food service waste stream. When soiled paper, which cannot be recycled, is included, the total proportion of the waste stream that can be composted is close to 70 percent.

Composting In New York

The New York State Department of Corrections has been a pioneer in institutional food waste composting. The DOC started composting food scraps from two of its facilities in the fall of 1990. Since then the program has grown to include 34 facilities, with more planned.

The composting program diverts about 400 tons of food waste per month from landfills and incinerators. Jim Marion, the DOC's resource management director, estimates that composting saves the department $118 per ton, although much of the savings can be attributed to inexpensive inmate labor.

According to Marion, an average of five pounds of food per day is prepared for each of the system's 60,000 inmates. From that five pounds, he calculates that about one pound per day of organic waste, including liquids, leftover foods and food preparation waste, is generated.

The compost produced at the prisons is used on state property for landscaping and agricultural crops. At a number of correctional facilities, inmates operate dairy and beef farms; compost is used on these prison farm fields to produce food for DOC staff and inmates.

Is Composting Feasible for You?

Before deciding whether composting is appropriate for your facility, you should consider two important factors: whether there is sufficient waste available at your institution for composting and whether the facility's finances make composting viable.

A consultant or producer of composting systems can be helpful in reviewing the suitability of your facility's waste stream for composting. To find out where you can enlist such expertise, contact your state's regulatory agency charged with solid waste and recycling, or check with the environmental engineering department or library at a local university.

In gauging the economic feasibility of a composting system designed for your institution, it is helpful to first determine the costs of continuing to send food waste and non-recyclable paper to a landfill or incinerator. These costs then can be compared to the projected cost of composting.

In estimating composting costs, remember to consider whether other organic wastes are available in your region that could be composted at your facility. A fee could be charged for composting those materials, helping to subsidize the cost of your system.

Setting Up a Program

If composting appears to be a viable option, the next step is to plan the composting facility. One of your first steps should be to meet with state and local regulatory officials to discuss the proposed project and obtain copies of all applicable regulations. Large composting sites usually are regulated by state, county or local agencies, some of which may have specific composting regulations in addition to normal construction standards.

It is advisable, and often required by state regulation, to have a composting facility designed by a licensed, qualified engineer. The engineer should provide needed expertise on the types of equipment to be used, control methods for contaminants and odors, measures to be taken in designing access roads, and the design of the composting pad (the surface on which the composting occurs).

Site selection is critical in setting up a composting facility. Most state solid waste regulatory agencies have minimum site requirements for solid waste processing or composting. Local zoning and health department regulations may also establish site criteria. The more space available, the greater the flexibility an institution has in the type of system it chooses and the amount of organic waste it can process.

A number of composting systems are available. These systems vary in cost, the volume of waste they handle and the climate for which they are suited. If a remote site in a dry climate is available, a simple outdoor approach is probably sufficient. Where more control is needed, you may have to use a covered composting pad or an enclosed system.

Depending on the type of material to be composted, grinding equipment may be needed. Other equipment to be considered includes blowers, turning machines, filtration systems for exhaust air, contaminant collectors and screens.

Operating the Program

A system for collecting compostable waste must be established. Separate containers for organics and other recyclables should be clearly marked in the kitchen and dining area. All organic material should be separated from other waste before being delivered to the composting plant. This reduces composting costs and results in a higher quality compost.

Organic waste can be held in a storage area and periodically loaded on a small truck and hauled to the composting facility. It is advisable to refrigerate the storage area to eliminate problems with odors and flies and to avoid having to process the waste daily during hot weather.

While composting systems vary, a typical method of operation is as follows: When a batch of material is ready for processing, reusable wood chips, chopped brush, or leaves are added to comprise about 40 percent of the batch. Food waste contains a high concentration of nitrogen, and the wood chips are high in carbon. These two essential ingredients sustain the microbes that convert the organic matter to humus. The wood chips also allow air to flow throughout the piles and supply oxygen to the microbes.

The microbial activity generates heat, which kills disease-causing pathogens. After six to eight weeks, the microbes have done their work and the wood chips are screened out of the compost. (These can be saved for reuse in other batches.) Following outdoor curing for several months, the compost is ready for use.

The end product, compost humus, may be used by the institution or sold for gardening, soil improvement, greenhouses and other agricultural applications.

Before marketing finished compost, you should have the material tested for its fertilizer nutrient content (nitrogen, phosphorus, potassium), since this affects the value of compost. In addition to its value as a fertilizer, compost improves gardens through the organic matter it adds to soil, which can increase the soil's capacity to hold water and suppress plant diseases.

One of the biggest detriments to compost quality is the presence of glass and plastic pieces. It is extremely important to keep these items out of the food waste. The alternative is to screen them out of the compost, which can be costly and is often only partially effective.

To reduce the presence of inorganic contaminants, particularly plastics, facilities can increase their use of biodegradable materials such as paper plates and napkins, and can replace plastic cutlery, lids and straws with completely biodegradable starch-based polymeric materials.

Composting requires careful planning and some capital investment. However, it saves on long-term disposal costs and can produce income from the sale of the end product. As prison populations grow and food waste becomes an increased economic, environmental and management problem, composting offers an alternative worth exploring.

Robert L. Spencer is an environmental planning consultant based in Dalton, Mass., and Kenneth D. Tracy, Ph.D., is vice president of environmental technology for Novon Products Group in Morris Plains, N.J.
COPYRIGHT 1993 American Correctional Association, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1993 Gale, Cengage Learning. All rights reserved.

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Author:Spencer, Robert L.; Tracy, Kenneth D.
Publication:Corrections Today
Date:Apr 1, 1993
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