It's Rotten

INTRODUCTION

The purpose of this memo is to look at the issues of planning, sitting, designing and operating composting facilities. It will be useful to the decision-makers, managers and potential operators of the facility, as well as to citizens who are interested in the composting process. The memo discusses several approaches to composting and outlines the circumstances in which each method should be considered.

The memo will discuss whether a composting operation should be designed according to the need and resources of the community. For example, a municipal composting effort can entail simply collecting yard trimmings on a seasonal basis and using a simple “windrow and turn” technology to produce the compost, or it can mean siting and designing a large facility that is capable of handling several tons of mixed municipal solid waste.

BACKGROUND

Composting is considered to be a form of recycling. Like other recycling efforts, the composting of yard trimming and solid waste can help the municipality dispose of solid waste that can’t be sent to a landfill or incinerator. Composting also yields a valuable product that can be used by farmers, landscapers, horticulturists, government agencies, and property owners as a soil amendment or mulch.

Composting is the manipulation of the natural aerobic process of biological decomposition of organic materials to increase the decomposition rate. This process is carried out by successive microbial populations that function under increasing temperatures to break down organic materials into carbon dioxide, water, minerals, and stabilized organic matter. The compost product improves the condition of soil reduces erosion, and help suppress plant diseases. Simply piling up leaves and allowing them to slowly decompose is not composting.

Since January 1993, state law bans yard waste—leaves, grass clippings, garden debris, and twigs, brush, and branches smaller than six inches in diameter—from landfills and most incinerators. This law does not apply to stumps, roots or shrubs with intact root balls, or incinerators which burn waste to recover energy.

The primary motivation for composting wastes is the law that prevents landfilling in the typical landfill. There are privately permitted landfills that may accept yard waste, but require dumping fees. The City is currently landfilling at the old Conservation Club, which is now the County Sheriff’s shooting range on CTH “V” near E. Mills Drive. The site was permitted for landfilling in 2004 and the city has used the site since then. The city previously hauled to a facility in Waterloo and paid a dumping fee. The cost in labor, equipment, gas and fees was substantial and hauling to the local site saved thousands of dollars. The County site will fill up in a couple of years and the Council needs to consider what options will be the best alternative for disposing of the yard waste materials.

Neighborhood composting facilities for grass, leaves, yard waste and food scraps which do not exceed a volume of 50 cubic yards of compost at one time need no DNR license or approval, provided the operation is nuisance free and certain performance standards are met.

Community yard waste compost facilities that handle between 50 and 20,000 cubic yards of material on the site at one time are licensed by the Regional DNR office for that area. These facilities must meet location, performance and reporting requirements set by DNR administrative code. All yard waste compost facilities that exceed 50 cubic yards at one time must be licensed by the department, regardless of when they opened for operation.

Yard waste compost facilities that handle more than 20,000 cubic yards of waste at one time are approved and licensed through the DNR central office and must meet the requirements for such facilities set by DNR administrative code.

When considering any type of composting effort, councilmembers must plan ahead to avoid potential obstacles that could hinder the operation. The most common challenges are siting the facility, ensuring that the facility is properly designed, mitigating and managing odor, controlling bioaerosols and investing adequate capital to cover unforeseen costs. Councilmembers should seek to understand and prepare for the challenges of potentially developing a composting program.

Yard waste (i.e., leaves, grass clippings, and shrubbery and tree prunings) at one time comprised an estimated 12 percent of the municipal solid waste (MSW) that was being buried in America’s landfills. During the peak grass clipping and leaf collection months of the spring and fall, that represented more than 50 percent of the MSW stream in some locales. Local governments in Wisconsin are required to enacted yard-waste disposal bans to increase the lifespan of landfills. Yard wastes should not be landfilled because they are relatively clean, biodegradable materials that can be recycled for soil improvement and other agricultural uses. A further advantage of recycling yard wastes is that they are easy to separate from the rest of the MSW stream at their point of origin.

Income from the sale of the finished product and saving the cost of purchased compost are potential financial incentives for setting up a composting operation. Considerable market research is necessary before entering the compost sales business because supply and demand is site specific.

An environmental benefit of composting rather than landfilling yard wastes is the reduction in the amount of methane, a greenhouse gas, released into the atmosphere. When organic materials decompose anaerobically in a landfill, they produce methane. When they decompose aerobically through composting, they do not. EPA estimates that increasing the national recycling rate to 35 percent from its current level of 28 percent would reduce greenhouse gas emissions by another 9.8 million metric tons of carbon equivalent.

While there are benefits to composting, waste-handling facilities (including yard-waste composting operations) can raise public concerns. Nearby residents should be alerted and educated early in the process of planning a yard waste composting facility. Well-educated and informed citizens often become the most vocal supporters for a composting facility.

ISSUES

When planning a municipal yard waste composting program, the following areas need to be addressed: quantity of material, equipment, material collection, facility siting, staffing, public education, and marketing/end use.

1.    Quantity of Material: Determining the amount of yard waste that will be available can be done through the use of established generation rates or actual weight studies. Since yard waste does not occur at a constant rate throughout the year, care must be taken in the analysis of collected data. In most cases, existing generation rates should be adequate.

2.    Equipment: Equipment for a composting program must be able to handle movement, turning, watering, screening, and monitoring of the material. Specialized equipment is available for collection and windrow turning, but is not necessary. The use of a screen does, however, create a uniform sized material which helps in the marketing of the end product.

3.    Material Collection: Collection of yard wastes for a municipal program can be separated into three categories: dropoff, curbside pickup in bags or other containers, or bulk pickup where the leaves are collected loose off the street. If bags are to be used for collection, it is advantageous to use biodegradable plastic or paper. This type of bag can be shredded and mixed into the compost while non-degradable plastic bags must be removed prior to composting. Bulk collection requiring the material to be scooped, raked, swept or vacuumed off the street, can be slow and may contain contaminants from the street. The choice of collection methods should be determined by cost, convenience, household participation rate, and the amount and type of yard waste to be collected.

4.    Facility Siting: Land requirement will be dependent on the volume of yard waste to be collected and the level of technology to be employed. As the level of technology increases, the amount of land required for processing decreases. In general, one acre of land can support 4,000 to 6,000 cubic yards of loose material. Criteria to be considered for a composting site are: location, size accesibility, soil drainage, surface water, topography, buffers, and security. It is important that the site be adequately sized to handle all of the current and future material that will be received at the facility.

5.    Staffing: A staff that is dedicated and that understands the material and the composting process is needed to ensure a successful program. Of the staff's responsibilities, the areas of windrow monitoring, recordkeeping, and quality control are the most important.

6.    Public Education: Education is a vital component of any successful composting program. Education and promotional programs should start as soon as the planning process is initiated. The information should answer these basic questions: what, when, why, how and where. Information can be distributed in a number of different manners with each targeting a different audience. Education should not stop once the program has started, but be a continuous process with updates and reminders to maintain interest and participation.

7.    Marketing/End Use: There are a number of uses for compost. As a soil amendment, it improves the texture, porosity and water holding capacity; it also increases the organic content of the soil. For mulch, it is placed around plants to suppress weeds, modify soil temperature, and conserve soil moisture. On slopes, it can be used for stabilization and reducing soil erosion. In a greenhouse or nursery, it can be used as one of the components of a potting soil mix.

The product can be given away, sold, or traded to residents, landscapers, nurseries, greenhouses, and local governments. It is usually distributed in bulk with pick up at the composting site by the user. As with any product, the higher the quality, the easier it is to market. Nurserymen and landscapers are more apt to reject a product with extraneous material in it, so if they are to be a major outlet for the compost, they should be contacted in the initial planning stages to ensure that an acceptable product is produced.

CONCLUSION

Once the Council has clearly defined the goals of its program, it will be easier to evaluate available technologies and determine the role that composting will play in the community’s overall management strategy. In addition to goal-setting is important to evaluate the economic and technical feasibility of composting in the context of other waste management techniques, such as landfilling and incineration, to determine which alternatives are most suitable for the community The costs and benefits of each option as well as relevant political and public opinion considerations can be evaluated to ascertain which mix of solid waste management approaches will best serve the community