Getting the dirt on composting

Many people do backyard composting to supplement gardens. Others buy it from their local garden center. Have you ever wondered how we can take waste and use it to feed plants that feed us? Get the dirt on composting.

Landfills

We tend to get confused about the difference between composting and land filling. A landfill is basically a place where we bury all of our precious resources and forget about them, including hazardous materials, food, paper, plastic, clothing, furniture, etc. Many of these items stay exactly the same for thousands of years.

In a study by Project Garbage and published in Michigan State University Extension, the study found items buried for over 30 years that were still intact, as if they were buried just yesterday; including a t-bone steak and five hot dogs. Most of what was found in the landfill was paper, which makes up about 30% of landfill debris in the United States.

The reason things do not biodegrade in a landfill is because there is very little water and no oxygen, which is creates an anaerobic atmosphere. (Learn more anaerobic digestion by turning animal waste into electricity and natural gas in Cow Power co-written by this examiner.) So don’t waste your money on biodegradable products. If biodegradable items become litter, especially fossil fuel plastics, they don’t disappear. They only become smaller and smaller pieces of plastic litter.

Meanwhile, paper can either be composted or recycled, but when it is left in a landfill and if it does break down it creates methane gas, a greenhouse gas, which traps much more heat on the earth than carbon dioxide.

However, when methane from organic materials mixes with mercury in older batteries, fossil fuels, thermometers, mercury switches, fluorescent light bulbs, etc.; it creates a deadly gas called methyl mercury. (This is why it is important to recycle batteries and fluorescent light bulbs.)

Compost

Composting is much different. A variety of organisms break down organic materials in a compost pile (bacteria, fungi, invertebrates, etc.). The organic materials must be turned and watered until they are as moist as a sponge, not any wetter or drier, which affects the organisms’ effectiveness. They need to be turned weekly and then less often in order to get the full potential of the bacteria breaking down the materials into food for plants.

Compost has an earthy odor, while land filling of organic materials generally has a foul odor.

Composting does not create green house gases because the organic material (food waste, plant waste, manure, etc.) becomes carbon and nitrogen, which energize and feed the roots of plants.

Compost is much more beneficial to liquid nitrogen or other liquid fertilizers, because it is slowly releases nitrogen to the plants over time. This means it does not have to be spread onto crops, gardens or lawns every season. Plus, according to Wes Hielscher from A1 Organics, it retains 40% more moisture, which means less watering and less erosion. Why are we throwing away these valuable natural resources instead turning them into natural fertilizer?

While paper in the landfill makes up about 30% of the waste, food and yard waste make up another 27%, which could be either recycled or composted. We throw away about 40-50% of all the food prepared each day in America. What is wrong with this picture? Are we so naïve to believe that these resources will be here forever and that no energy or pollution was created to extract, build, plant, deliver, sell and prepare these precious resources we rely upon for our survival?

Instead of land filling everything, why not reduce, reuse, recycle and then compost? Waste in the landfill is rapidly increasing over the last 30 years, but recycling is steadily increasing nationwide to about 35%. However, when it comes to composting the amount is less than 1% nationally. Don’t we want to have healthier foods, use less fertilizer and water on our crops and gardens? Why not try composting?

A1 Organics

This examiner recently visited the largest industrial composting company in Colorado and was guided by Wes Hielscher, Senior Account Executive at A1 Organics.

A1 Organics has several facilities on the Front Range that accept all types of plant matter from yard waste, food waste, sod, soil and old wooden pallets. Much of it is delivered to the Stapleton site near the Rocky Mountain Arsenal. This facility is a drop off point for food and yard waste, but also a processing center for soil and wood waste.

Food waste with fewer contaminants, including plastic, metal, glass, cardboard and even compostable bags, are dumped into a doda. Only three of these machines are being used in the U.S. A doda liquefies compostable material using an oscillating auger and a centrifuge that sorts the liquid from the solids. Each day a tanker truck holding 6000 gallons of this liquid compost is trucked to Keenesburg. This liquid gold will speed up the composting process.

Unfortunately the doda cannot discriminate between compostable bags and plastic bags. Therefore loads that carry bags or other items not suitable for the doda must be piled outside of the unit. Some items that we found that day in the pile were cardboard boxes, which could have been recycled into new boxes. This could save more trees and require less energy, which is better than composting them. There was also a great deal of food waste like bread and vegetables from different businesses.

Food waste (brown waste rich in nitrogen) is transferred from this facility to the Keenesburg location, which is one of the largest in the country, covering 442 acres and is the largest in the state. Only a third of the site is currently being utilized.

The green waste, which includes yard waste such as grass clippings and leaves, contain a great deal of carbon. These are mixed with the food waste to make rich compost sold at many of our local garden and hardware stores.

The Stapleton location primarily composts soils into top soils and chips wood waste into mulch and fines. Much of the wood waste chipped into mulch and wood chips are made from wooden shipping pallets, which Hielscher states are the “cleanest” wood to use, as they don’t contain wood preservatives, stains, paints or other chemicals.

We watched as the wood was chipped and then processed through a plant-based dye to make brown, red, rose or even black wood chips. These painted chips rose up onto a conveyor belt into colorful piles soon be used in landscaping projects. Much of this mulch and wood chips are sold under the Scott’s brand. They also process some of the wood into smaller particles called fines. These are sold as animal bedding and biofuels.

Any soils brought to the Stapleton facility must be thoroughly tested prior to their delivery for heavy metals and other contaminants, as these are composted and sold back to consumers to use as top soil in farming, road projects, landscaping, construction projects and gardening.

Composting at A1 is much different that composting in someone’s backyard. Each pile or windrow at the Keenesburg site is about ten feet high and 150 feet long. They reach temperatures of 160-180 degrees Fahrenheit in the center of the pile all year round. Machines turn and water the materials regularly, especially within the first 15 days.

Technically A1 could compost a cow carcass within a couple of months. All of the organic material is completely composted within 6-8 weeks and any weed seeds and other organisms will die in these harsh conditions, except for the micro-organisms that consume the organic materials to make a perfect food for your garden or farm.

A1 Organics composts a wide variety of organic materials, including animal manure, feathers, meat, dairy and much more. These materials that are more difficult to compost in your own backyard pile. Consider composting your leaves, yard waste, non-recyclable paper (tissues, construction paper, bright and dark paper and paper towels) and food waste to make a healthier planet.

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, Denver Green Initiative Examiner

Michele is an environmental educator for non-profit and teaches in energy, zero waste, and other environmental presentations and classes. She's also the Green Star Schools Coordinator for Eco-Cycle in Boulder. Her passion is to educate the public to learn to live with nature through sustainable...

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