Quality matters, and the time and care compost producers take during the composting process can mean the difference between large profits and almost having to give end-products away. And while there is science involved with producing the highest quality compost in the shortest period of time, raw material handling plays an instrumental role in making compost that is in high demand. Grinders (tub grinders and horizontal grinders), compost turners and screening equipment are vital to producing high-quality compost material.
Read on to find out how and why.
The role grinders play in producing quality compost
Organic material (wood, leaves, grass clippings, etc.) will eventually decompose over time, but using a horizontal grinder and/or tub grinder in daily operations to grind bulky material helps speed up nature’s process — and compost producers’ production time.
The consistent particle sizing created by grinders also matters in the decomposition process. Here’s why: Microorganisms — bacteria and fungus — living within and on organic material are responsible for the composting process. Grinding bulky material into smaller particles increases the surface area for these microorganisms to do their job. Material sized between 2 to 4 in (6.4 cm to 10.2 cm) is the optimum size most expert compost producers prefer. This size range helps windrowed or piled raw compost maintain an optimal temperature for the decomposition process to happen while not being too small to prevent oxygen from flowing freely through the pile.
Mike Dimucci, Garden Prairie Organics (GPO) manager in Garden Prairie, Illinois, understands grinders’ importance in the composting process. His team uses a multistep, closely monitored process with measured inputs of water, air and carbon- and nitrogen-rich materials. The decomposition process is aided by grinding the plant matter, adding water when needed and ensuring proper aeration by regularly turning the mixture.
GPO operates a Vermeer TG7000 tub grinder to process incoming material. “We mix the way we want it, put it out in the windrows and take the temperature, as well as check the oxygen and moisture levels,” Dimucci said. “Then, we run our Vermeer compost turner through it and process it up. Once it’s finished material, we’ll cure it, run it through one of our two screeners and then finish with a premium compost.”
Compost turners help optimize oxygen flow and keep odors in check
Compost producers committed to producing the highest quality end-products understand that the composting process takes time. But there are ways they can speed things up. That starts with ensuring their yards are set up correctly. Plus, most choose to windrow over stacking materials during the curing process. Stacked piles of materials take longer to decompose than windrows and release odors as the material sits. Even worse, they can overheat and spontaneously combust. Windrows allow material to be turned and be more easily irrigated (if needed) during the curing process. And the most efficient and thorough way to turn the compost is with a compost turner.
Why do windrows need to be turned?
Turning composting material improves oxygen circulation during the curing process, helps ensure moisture is evenly distributed and speeds up the decomposition process.
Chris Cowart, the owner of Cowart Inc., said they used to use wheel loaders to turn compost. “We determined we needed to add a compost turner to our fleet to improve our overall efficiencies. We wanted to go from doing it one way to doing it the right way,” he explained.
Cowart Inc. is a large provider of high-quality composts and mulches and tree care services for the Southeast region of the United States. They operate a fleet of more than 900 machines in seven locations and employ more than 100 people. Cowart says that how often windrows need to be turned is dependent on the material type, climate, moisture levels and how quickly it needs to be broken down. Material that breaks down quickly should be turned daily at the start of the curing process, and weekly later. Food waste that gets mixed into composted material should be turned promptly to help prevent odors. Since making the switch to the Vermeer compost turner, Cowart has seen a difference in the quality of their product. “We know everything is getting turned over properly, which leads to an increase in oxygen levels, and the result is a much higher-end product,” said Cowart.
Screens help ensure the highest quality end-products
Most compost customers are looking for specific soil blends based on the application. Growers, landscape contractors, municipalities, resellers, golf courses and farmers expect soil blends to work for their needs. This is where screens (trommel and deck screens) are useful.
Screening material ensures that compost producers have the desired sizing for each of the different markets they serve and helps remove contaminates like rock and plastics. Customers don’t want to see that in their compost mix. Appearance can strongly impact what they think of the products and what they are willing to pay for them.
Screens also help blend compost with other materials. For example, many golf superintendents prefer a compost product with some sand mixed in. At the same time, farmers are okay with larger material sizes, if it spreads easily and can be worked into the soil.
For example, Freestate Farms’ Balls Ford Road Composting Facility in Manassas, Virginia, uses Vermeer TR626 trommel screens to produce high-quality end-products. According to Jeffery Morton, operations manager for Freestate Farms, screening is vital in creating quality end-products. “Incoming material gets run through our grinder, then stacked in windrows and regularly turned to make sure there are adequate oxygen levels,” he said. “That part of the process usually takes between 6 to 8 months.”
“After that,” said Morton, “we screen off the larger material, leaving us with nutrient-rich compost and soils used by growers and consumers. The larger material is then turned into dense nutrient mulch or added back into the composting piles.”
Morton went on to say, “Screening takes time and is often viewed as a bottleneck in the composting process, but it doesn’t have to be that way. After trying several different models of trommel screens on the market, we discovered that the Vermeer TR626 trommel screen was the right fit for our operations. It’s convenient to operate, reliable and consistently produces no matter what the moisture content is outside.”
What are your goals?
Many compost producers get into compost unintentionally. Some individuals start in wood waste recycling and profit from tipping fees but soon become overwhelmed by the volume of material piling up. Others are landscapers looking to expand operations. Whatever the reasons are for getting into the compost industry, the quality of the end-product matters to customers. Using the proper equipment in every part of the business’s operations can help produce high-quality, desirable compost and soil blends.
Contact your local Vermeer dealer if you need help deciding which grinder, compost turner, or screen is right for your operations.
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