A PRACTICAL GUIDETO COMPOSTING

THE COMPOSTING SEGMENTOF THE RECYCLING INDUSTRYCONTINUES TO GROW

THE FOLLOWING DRIVERS ARECONTRIBUTING TO THE GROWTH:

Regulatory Requirements

• State and local requirements to divert greenwaste from landfills

• Federal water and environmental protectionstandards

• Requirements to use compost products to control erosion

Economic Incentives

• Increasing landfill tipping fees• Cost of alternative use and disposal• Incentives to expand recycling

Business Growth

• Demand for organic fertilizers, soil conditioners,and compost products

Recycling has grown substantially in the United States with more than 4,000 registered recycling locations today. The compost segmentof recycling has grown into a multi-million-dollar market and continues to grow globally as communities divert green waste from landfillsand explore new methods to utilize animal waste.

MARKETS:

Compost products have many everydayuses and applications, such as:

• Top-dressing for yards and golf courses

• Compost socks consist of mesh tubes filledwith compost that will slow and filter water ona construction site capturing soil and reducing erosion.

• Compost blankets can control erosion on dis-turbed areas such as construction sites, stateDOT development (and planting) projects, andexposed stream banks.

• Organic fertilizer or soil conditioners

ANAEROBIC COMPOSTINGAlmost any organic material can be processed in this manner. This includes biodegradable materials such as waste paper, grass clip-pings, leftover food, sewage, and animal waste. This composting process enables organic matter to be broken down by bacteria in theabsence of air. Anaerobic composting may be accomplished in large, well-packed stacks or other composting systems (silos, bags,digesters, etc.) where little oxygen can penetrate. While anaerobic composting may be less labor intensive because you don’t need toturn the pile, it creates a strong odor, and takes longer to finish as the organisms do not have as high a metabolism.

AEROBIC COMPOSTINGAerobic composting is the process by which organic waste is converted into compost in the presence of air. During aerobic composting,the water content in the biodegradable material is removed. Aerobic composting reduces the waste into nearly one-half of its originalvolume and the process usually takes from two months to one year. The organic material is arranged to provide some insulation andtemperatures during decomposition will rise to over 135 degrees Fahrenheit. If the temperature exceeds 170 degrees Fahrenheit, however, the bacterial activity is decreased and stabilization slows. This process requires that the material be frequently turned in order to introduce oxygen to the material.

Composting is a natural process of decomposing organic materials by using micro-organisms under controlled conditions. During thecomposting process, micro-organisms consume oxygen while feeding on organic matter. Active composting generates considerable heat,large quantities of carbon dioxide, and water is released into the air. This loss of carbon dioxide and water can amount to half of theweight of the initial materials. Composting thus reduces both the volume and mass of the raw materials, while transforming them into avaluable end-product.

COMPOSTING

Passive pile – This process involves building a static pile of organic material which is packed and will not receive aeration.Passive piles generally have large areas that are anaerobic.

Passive windrow – Organic materials are mixed with raw material (animal waste or sewage) and formed into long windrows.Perforated pipes are placed into the windrow and allow air to access the windrow through natural convection.

Windrow composting – This is a common composting method. Organic material is placed in long windrows and the material is turned periodically to accelerate the composting process and provide uniform compost. An open space is leftbetween each windrow to allow room for turning equipment.

Aerated static windrow – This process is similar to the passive windrow concept except that the pipes inserted into thewindrow have forced air that is either positive or negative aeration.

Extended windrow (stacking) – Areas of limited space rely on this process. The process uses one continuous windrow cov-ering the whole processing area, with the absence of an open space between the windrows. This process will allow for threeto four times more material to be placed in the same space as conventional windrow composting, because there is no needto leave open space between the windrows.

Invessel composting – Organic materials are stored in tunnels or movable containers. This method seals off the outsideworld to prevent odor discharge.

COMPOSTING METHODS

COMPOST TURNING EQUIPMENTFront-end loader – A front-end loader can be used to turn the windrow, how-ever using this method requires additional space between the windrows, and itmay be difficult to effectively turn the pile in a manner that will introduce oxygeninto the material. Turning compost windrows with a front-end loader may resultin a delayed decomposition process, as oxygen may be introduced evenly intothe entire windrow and may result in a less valuable end-product.

Drum turner – These PTO-driven or self-propelled units feature a horizontalsteel drum with paddles that turn rapidly to mix fresh air into the compostwindrow. While these units are efficient in turning the organic material, they typically grind or pulverize the compost material causing physical degradation;the compost material will compress and restrict air flow into the windrow, whichslows the decomposition process. These units also have difficulty turning material all the way down to the composting pad because they cannot be set lowenough to effectively scrape compost from the pad, leaving a layer of compostthat may not decompose properly. Since the material tends to compress andrestrict air flow, compost operations may need to turn the compost windrowmore often so the material remains aerobic.

Auger – This turning machine uses an auger, or auger-like paddles, to lift andmove the windrows to one side or the other. Auger-type turners are manufac-tured to mount on the front of a skid-steer loader or wheel loader. The turningmechanism for most models is powered by the tractor or loader’s hydraulicpower transmission system. As an auger turner moves down the length of thewindrow, it moves the material to one side, nearly eliminating the need for spacebetween windrows.

Elevating face turner – The elevating face (or elevating belt) turner is essentially awide backward-sloping conveyor with cleats or teeth that lift the compost up and overitself, completely inverting the windrow. The teeth do not reduce particle size, thus reducing compaction and introducing and trapping oxygen in the material to help speedthe decomposition process. For extended windrows (stacking), additional conveyors onthe back of the turner place the compost in the desired location on the composting pad.These units can vary from pull-behind to self-propelled.

WINDROW COMPOSTING Windrow composting and extended windrow (stacking) is a commonly usedcomposting method. The organic material is formed into long piles that are typi-cally five to 10 feet high, 10 to 20 feet wide, and up to 300 feet or more in length.Extended windrow composting does not require open space between thewindrows.

Windrows can be placed directly on a compost pad (lime stabilized soil or pavedarea), but you should review regulations in your area to make sure the compost-ing pad meets local and state requirements. The size of the land requirement fora windrow composting facility depends on the volume of material to beprocessed. Generally, all of the material handling and pile building can beaccomplished with a front-end loader.

The windrows should be aerated periodically to inject fresh air into the pile,removing the waste gas. Fresh air contains oxygen that feeds the beneficial com-posting bacteria and thus speeds the composting process.

Following the composting period, the windrows are broken down or moved andreconstructed into curing piles for additional aging and drying. This curingprocess allows partly decomposed compost particles to finish the compostingprocess at a low temperature. This should take approximately 45 days and allowscompost to stabilize so odor is no longer present, and the material can be storedwithout further decomposition.

After curing, the compost should be processed with a trommel screen which sep-arates the larger pieces from the finished product to achieve the desired finalcompost product.

To speed the composting process and provide beneficialbacteria, windrows should be turned on a regular basis.

A compost turner:• Allows the compost process to progress faster• Produces a quality and uniform product• Is generally more productive and economical than a

bucket loader because it can turn the windrow in amore efficient manner

For more information on composting equipment, contact your local Vermeerdealer or go online at Vermeer.com.

Tub Grinders

Vermeer® tub grinders enhance productivity,efficiency, and safety. With high-capacity discharge systems, one-pass grinding, patented Thrown Object Restraint Systems,sturdy loaders, and countless other features,it’s no wonder that Vermeer is at the top of the pile when it comes to tub grinding.

Horizontal Grinders

Vermeer horizontal grinders are built toughand available in a variety of configurations tosuit large land-clearing and municipal wasteoperations. Vermeer horizontal grinders feature remote-controlled operation, an exclusive feed system, the patented VermeerDuplex Drum, and many other productivity-enhancing features.

Compost Turners

The Vermeer-exclusive elevating face compost-turning equipment is specificallydesigned for use in large-scale compostingand bioremediation operations. Elevating facetechnology gently inverts a compost windrowwithout reducing particle size, and introducesoxygen into the material to help speed thedecomposition process.

VERMEER DEALER NETWORK

Vermeer and its independent, authorized dealer network located throughout the world can assist your composting operation by helping you select the right horizontal or tub grinder and compost turner for your operation. Our dedicated dealer network is alsothere with exceptional service and support after the sale.

VERMEER and the VERMEER LOGO are trademarks of Vermeer Manufacturing Company in the United States and / or other countries.© 2007 Vermeer Manufacturing Company, All Rights Reserved.

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