Anne Arundel County has more horses than any other county in the nation. It follows that we also have more horse manure. Some of that horse manure occupies precious landfill space or is dumped near streams, thus contributing to Bay pollution.
Anne Arundel County landfills also have too much of another organic waste, nitrogen-rich food waste produced by an abundance of restaurants. Like yard debris, neither of these organic wastes should be occupying landfill space. Landfills are costly to construct and maintain. Both food waste and horse manure can easily be converted into compost.
In the early 1980s, the Bay Gardener was involved in writing the state law that prohibited the dumping of yard debris into landfills and established yard debris composting facilities. One such facility is located near Upper Marlboro, just a mile from the Anne Arundel County line, near the intersection of Route 4 and Route 301. Operated by Maryland Environmental Services, it is one of the locations that manufactures LeafGro.
Last month, the Anne Arundel County Council and the County Executive approved the composting of horse manure and restaurant waste on South County farms in facilities between five and 10 acres. The legislation has established strict standards that limit the area for compost to 25 percent of total acreage. Prohibited from composting are dead animals or waste from processing facilities. The new legislation also limits proximity of composting pads to adjacent properties, occupied dwellings and streams. The composting must be done on a non-porous pad, and the facility must be managed by an operator certified in the science of composting. The location of any such facility must be pre-approved. Also considered in the legislation is road access to the facility.
The Maryland Department of Agriculture is responsible for certifying managers of composting facilities. Certification requires a training program and rigorous written exam. As Maryland was the first in the nation to establish a commercial composting training program, I prepared many of the questions that are included in the certification exam. Managers must be knowledgeable in the biological processes, monitoring equipment, standards and management procedures.
The Maryland Department of the Environment is responsible for inspecting and assuring that the facilities are properly managed and that sanitary conditions are maintained. Maryland’s composting facilities have been operating for the past 30 years without creating problems while producing such compost products as LeafGro, Orgro and Veterans Compost. Many municipalities compost their own yard debris, making it available to residents at a minimal charge, following standards established within their jurisdictions without creating odors. Near Exit 1 on the Baltimore Beltway, a composting facility processes 180 to 200 tons of Baltimore sewage sludge each day without creating an odor problem, producing compost called Orgro.
Composting is an exact science. It requires blending the proper amount of feedstocks; in this case horse manure with restaurant waste. The amount of carbon and nitrogen in each are determined by established laboratory testing methods. After these two materials are blended properly in the correct amounts and placed in windrows, moisture levels are maintained between 50 and 60 percent and oxygen levels are maintained above five percent. Temperatures within the piles will average between 140 and 160 degrees within 24 to 36 hours. When oxygen levels drop below five percent, the windrows are turned with specialized equipment to introduce more oxygen into the mixture. Some composting facilities draw air, using fans, through the composting piles to maintain oxygen at the proper level. Only when the temperatures within the piles achieve those near ambient air is the compost ready. The process will generally require 80 to 100 days, depending on the time of year and the volume being composted. The resulting compost has a rich earthy smell.
The microorganisms that digest the carbon in the horse manure, while using the nitrogen from the restaurant waste, are the same microbes found in garden soils. The same process occurs on the forest floor. Science has discovered that under ideal conditions, these microorganisms will gladly work overtime.
The only by-products of composting are water vapor, heat and carbon dioxide. There are no toxic gasses released during composting.
Gardening has become the most popular hobby in the nation. Ornamental horticulture is the second largest income-producing agricultural industry in Maryland, second to poultry. Potted plants are all grown in soil-less blends containing one-third to one-half by volume compost. With more people demanding organically grown food, the need for compost far exceeds the supply. Compost is a great soil amendment and a good source of slow-release nutrients.
I have spent more than 30 years conducting research on using compost made from sewage sludge, animal manures, yard debris, crab waste, garbage, paper-mill sludge and more. Composting is the ultimate in recycling, and it can be done safely and efficiently. Although composting is an old agricultural practice, today’s composting technology is as different as the Model A Ford is to today’s hybrid cars.
Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.