«Guide to Recovering and Composting Organics in Maine Maine Department of Environmental Protection Guide to Recovering and Composting Organics in ...»
Guide to Recovering and Composting Organics in Maine
Maine Department of Environmental Protection
Guide to Recovering and Composting
Organics in Maine
Pre-consumer food scraps ready for composting.
Photo by Mike Burden, University of Missouri College of Agriculture
Mark A. King and George M. MacDonald
Maine Department of Environmental Protection
Bureau of Remediation and Waste Management
MAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION17 State House Station | Augusta, Maine 04333-0017 www.maine.gov/dep Guide to Recovering and Composting Organics in Maine Maine Department of Environmental Protection Table of Contents I. Introduction………………………………………………………………………………...…………….………page 4 II. Identification - Separation – Transportation – Issues and Concerns………….……….page 5 A. Why do it?
B. Why now?
III. The Composting Process
A. Four Common Composting Systems used in Maine ……………………..……………page 10
1. Static Pile
2. Aerated Static Pile
3. Turned Windrow System
4. In-Vessel System ………
B. Challenges to Managing Organic Residuals..……………………………………….……page 14 IV. Regulations ………………
V. Making Compost
A. Setting Up the Composting Site
B. The Working Surface
C. Site Operations and Management
1. Recipe Development
2. Feedstock Preparation Options
3. Mixing and Pile Formation
VI. Trouble Shooting the Compost Process
D. Dust, Noise and Traffic
Condensed Composting ‘Trouble Shooting’ Table……………………….……..…….page 33 VII. Overcoming Challenges …………………………………………………………………………………page 34 A. Composting in Maine
B. Winter Composting
C. Seasonal Availability of Feedstocks
VIII. Compost Health and Safety Issues
A. Categorizing and Addressing the Hazards
X. Resources Available …………………………………………………………………………………………page 39
I. Introduction Since the early 1990’s, Maine has been steadily working toward a goal of annually reducing the solid waste it generates by half, through recycling and composting programs. With the assistance of residents, businesses, municipalities, and the state, numerous programs and efforts have been instituted and have been successful in capturing inorganic waste products (i.e., newspaper, corrugated cardboard, plastics and similar materials) from the waste stream and shipping those materials to be used in manufacturing. Little attention has been paid, however, to the organic fraction of the municipal solid waste stream. Food scraps and discards, along with lawn clippings and similar vegetative materials, account for over twenty-five percent of the solid waste stream and offer the possibility of reaching, and surpassing, the fifty percent recycling goal if these organics can be collected and recovered through composting programs or as a feedstock in an anaerobic digester.
In August 2012, the ME DEP created the Division of Sustainability with one its missions to provide technical assistance and outreach to public, municipal and private entities, encouraging enhanced recycling and composting/organics recovery activities. A goal is to assist municipalities, institutions and businesses in recognizing the value of organics and assist in the growing need for focused organics recovery and management.
This document recognizes that organics management includes vegetative discards, such as grass clippings, leaves, weeds and similar landscape materials, and includes food scraps as well. Handling farm animal wastes such as manure is not addressed per se, but reference to the use of manures and bedding materials is made in the sections on composting, since these products have value when utilized in a composting operation. Pet wastes, from dogs and cats, is not encouraged to be included with composting of landscaping materials or food scraps, due to potential health issues with the resulting compost.
The purpose of this document is to provide basic information for those interested in capturing unwanted organics from the waste stream and aiding in turning them into a beneficial product or use. Within this document the reader will find ways and methods of diverting organics from trash, learn the fundamentals of the biology of composting and various composting systems, the regulations that will help guide a program, as well as numerous resources available to assist in the effort.
Guide to Recovering and Composting Organics in Maine Maine Department of Environmental Protection II. Identification - Separation – Transportation - Issues and Concerns There are two significant challenges that must first be overcome before successful utilization of the organic portion of the waste stream will occur. The first is informing residents and businesses of the value of diverting organics from the waste stream, and gaining their support in separating organics from trash. The second is securing support from haulers and receiving facilities to accept and appropriately manage these organics.
But the first step to gaining support is the better identification and understanding of the various components of the organic discards stream, and sharing that information with residents and businesses that generate these materials.
Leaf and yard trimmings, and similar landscape residual organics, are widely understood and often are diverted from disposal, and used ‘on-site’ as mulch or in a backyard compost pile. Food scraps from the family dinner table may be added to these compost piles; but, there are many opportunities to expand the separation, collection and composting of food scraps generated from restaurants and institutions. Many of these practices are covered within this document.
Organic food scraps fall into one of two sub-categories: pre-consumer residuals and postconsumer residuals. Note: both categories may also include various types of paper products, such as napkins, wipes and towels. Pre-consumer food residuals are food residuals left over from meal preparation and grocery stores’ ‘pick overs’ or unsold items.
Generally, pre-consumer products have not been cooked or processed except for any initial packaging prior to sale. Post-consumer food residuals are any leftover, uneaten food that has already been served.
Similar to the ‘waste management hierarchy’, there is a ‘food recovery hierarchy’, which establishes a priority of actions in appropriately managing unwanted food and its residuals.
That hierarchy should guide our efforts in reducing the amount of unwanted food
produced, and aid in achieving the state’s 50% goal. The hierarchy is:
A. Reduction of the volume of surplus food generated at the source;
B. Donation of surplus food to food banks, soup kitchens, shelters and other entities that will use surplus food to feed hungry people;
C. Diversion of food scraps for use as animal feed;
D. Utilization of waste oils for rendering and fuel conversion, utilization of food scraps for digestion to recover energy, other organic waste utilization technologies, and creation of nutrient-rich soil amendments through the composting of food scraps;
and E. Land disposal or incineration of food scraps.
Guide to Recovering and Composting Organics in Maine Maine Department of Environmental Protection In general, pre-consumer food residuals are more easily composted because these scraps are generated within the kitchen or at a designated area within a retail store, and contamination can be easily minimized. Training of staff is also fairly easily done and monitored. Reducing the level of ‘non-organics’ within the collected organics is critical from a compost management perspective; for example, keeping plastic wrap out of the separated organics is critical, as plastic is an unwanted item at the compost facility.
Post-consumer food separation and temporary storage may require additional monitoring by trained staff to reduce the risk of contamination.
Before starting a food separation program, it is critical to identify potential storage space within the generating facility, secure transportation services for the food scraps to be delivered to an approved facility (composting, anaerobic digestion, other) and establish a relationship with that facility. It may be that the hauler will not have an arrangement with the receiving facility and it will be up to you to develop that, or perhaps the hauler already has a working relationship with an acceptable facility and your business becomes part of the service route for the hauler.
It is recommended that you start with pre-consumer food separation, which is the easier step to undertake in recovery food scraps and allows for the establishment of a successful collection system. This provides an opportunity to refine the collection/transportation aspect of organics management. Once that system is in place and working well, the postconsumer food residuals can be added to the system.
Continuous employee/consumer education, getting employees/consumers to “buy into the system”, and monitoring will help reduce the need to devote to the separation of materials, as will the use of color coded bins and appropriate signage. Once employees have been trained to the system, there will be only a minimal need for extra time to separate materials as it becomes part of the normal work routine.
Part of the initial program set-up is to identify the types and volumes of food residuals the facility will be generating. A fairly simple way to accomplish this estimation is to measure all of the residuals produced in each area during a typical operation week and project this amount over time.
For example, to undertake this measurement effort, measure one typical container of food residuals and multiply this amount by the number of containers that are filled during that week. Keep employees informed of the process to ensure containers contain food residuals only. Typically, disposal costs are billed by the cubic yard (a volume measurement). To convert weight into volume, here are some standard container sizes their volume capacities: 5 gallon container = 0.025 cubic yards; 30 gallon container = 0.15 cubic yards; 55 gallon container = 0.27 cubic yards (National Solid Waste Management Association, 1985).
Guide to Recovering and Composting Organics in Maine Maine Department of Environmental Protection Volume-to-weight conversions for food waste can vary considerably, depending on the type of food and its moisture content. If trash disposal at your facility is measured and billed by the ton, a standard container filled with representative samples of your facility’s food residuals should be filled, and then weighed for an approximate conversion between volume and weight.
If an on-site composting program is planned (where the proper mix of feedstocks is important) measuring the food residuals will be critical in developing the recipe for the composting process. Food residuals are typically wet, heavy and provide a source of nitrogen for the composting operation, which will need to be balanced with a material(s) that provides a source of carbon and can ‘lighten’ the food scraps. Before developing an on-site composting program, it is critical to determine whether food residual composting is right for the business. That review requires a thorough assessment of the facility’s waste generation and disposal practices, and assistance is available for that review. Most successful composting programs are individually structured to meet the financial and operational opportunities and constraints of a given operation.
Currently, there are approximately 20 Department licensed composting facilities, about 10 ‘on-farm’ operations that compost food residuals, and several ‘on-site’ composting operations for restaurants or institutions.
It is fairly standard that a composting facility charge a ‘tipping fee’ when accepting organics from generators. Tipping fees may range from $30 to $40 dollars per ton on average, as opposed to most of Maine’s disposal facilities which currently charge $65 or more per ton.
Even with the cost of trucking added, composting can make economic sense for most organics generators.
A. Why do it?
1. Lower Costs Composting can be a lower cost management method as compared to the cost of disposing the same materials at a landfill or waste to energy facilities. Also, managing organic residuals through composting or anaerobic digestion provides benefits by creating products with value, and aid in extending remaining landfill capacity.
2. Environmental Benefits Diverting organic residuals to composting sites reduces the potential for water and air pollution from landfills, and reduces air emissions and residues from waste to energy facilities. Compost can be used to improve soil quality, reduce water consumption needs of landscape plants and reduce non-point source pollution from the use of chemical fertilizers. Recovering food scraps and utilizing them through a composting process or directed to an anaerobic digester reduces the carbon footprint of your facility.
Guide to Recovering and Composting Organics in Maine Maine Department of Environmental Protection
3. Enhance Public Relations Through Educational Outreach Organics have value, and by informing and educating residents, businesses, and institutions to the benefits of a properly managed and promoted community compost program, an opportunity to promote environmental stewardship through sustainability is created. People can support the recovery of food scraps, receive positive reinforcement for their efforts and may be able to use the finished compost for their own use.