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March 2007

Equipment Spotlight

Composting Equipment

—View a list of manufacturers at the bottom of the page

A trend towards efficiency and lower-costs is taking hold in the commercial-grade composting equipment market, driving in-vessels and front-end loaders to the wayside and pushing technologies like the open-pile systems and composting turners to the forefront.

“Over the last 20 years there has been a move towards bigger composting facilities and animal feeding operations have become more common,” said Tim O’Hara, Western United States and Canadian sales manager of the South Dakota-based Wildcat Manufacturing Company.

High-maintenance costs and space considerations have led composting equipment manufacturers to abandon technology like the front-end loader because of its inconsistent finished product. In this quest for efficiency the compost turner has emerged as a winner because it boasts remarkable turning strength and requires less land to operate, O’Hara said.

This trend towards the compost turner is not limited to efficiency. Composting machines are now held to higher standards, thanks to a general public that is more savvy than ever about their composted product, O’Hara noted. The equipment is now expected to produce so-called "designer compost" — different blends to suit the needs of customers, he said.

“The contemporary consumers of composting know that if wet compost emits an odor, the composting was not done adequately,” he explained. “A way to use equipment to make the best possible compost product is by using mechanically-aerated windrows and by using a compost turner.”

Reotemp Instrument Corporations  Heavy Duty and Fast Response Windrow Thermometers

The company’s Compost Turner is in step with these quality and efficiency standards because the drum works 75 percent of the cross-section of the windrow, he stated. “The drum diameter is one of the largest on the market,” he added.

Products such as the Cougar Trommel Screen combine digital wizardry with user-friendly features. “[The Cougar has] the only trommel screen that you don't have climb up on the machine to do daily adjustments – it's a safety issue for us,” O’Hara explained.

The pull towards larger, more efficient facilities is not without price, warned Steve Diddy, project development manager for the Seattle-based Engineered Compost Systems. “For example, large windrow compost facilities have the least amount of odor control, and are often threatened by encroachment, urbanization and new air pollution regulations,” he said. Possible solutions include upgrading to a technology with better odor control such as in-vessels or simply relocating facilities. “Windrow facilities are also becoming more difficult to permit,” he noted.

Even so, cost-saving trends are reflected in the company’s products such as its AC Composter, a cost-effective tool for controlling odors and maintaining moisture levels during composting, Diddy said. It also includes near-zero fugitive odor releases, minimizes evaporative water losses and guards against distracters of the composting process, such as birds, rats and flies, he added.

Technology that simply eases the job of composting is also a popular shelf item. The company’s computer-controlled CompTroller automates the amount of aeration to each compost zone depending on its cooling requirements, Diddy stated.

Engineered Compost Systems AC Composter

Computer-controlled programs are also gaining momentum as a way to control open-pile compost systems, said Michael Bryan-Brown, president of the Washington and Vermont-based Green Mountain Technologies. The method was developed by adapting the computer control systems developed for in-vessel systems to aerated static pile systems. Although the ability to completely contain odors is lost when eliminating the container, this method is considerably more cost-effective, he added.

Rising steel costs have resulted in vessel systems falling out of favor and being replaced by the cheaper open pile systems.

“Open pile systems provide the large volumes of processing capacity at one site which is very attractive yard waste composting,” Bryan-Brown said. “We call this product the CompDAC’s system and it provides automated control for blowers providing forced aeration to open piles.”

Green Mountain Technology's computer controlled aerated pile system can automatically reverse the air flow direction and incorporates other sophisticated features such as automated temperature and oxygen recording, he states. For instance, the system conducts all the data management tracking and stores recipe calculations.

“Another product we developed in the last two years is the Windrow Manager,” he says. “This system is designed for facilities that don’t have aeration blowers. Instead of controlling the blowers, software automates the collection and management of temperature, oxygen and moisture data for regulators and operators alike.” The product integrates all the responsibilities such scheduling turning, calculating recipes, tracking weather data, he says.

Open piles are particularly sensitive to moisture control issues, which can lead to excessive odors being emitted. An effective method for moisture control – whether it is a cover or roof or other approach – is a challenge for open pile composting, Bryan-Brown cautioned.

“One way Green Mountain Technologies is helping is the development of a sensor for moisture,” he added. “The sensor will be used with Windrow Manager and will let the operator know if the compost is too wet or dry to compost effectively.”

It’s clear that the consumer’s heightened appreciation of efficiency and desire for higher quality compost has resulted in some pushes and pulls within the composting industry, but manufacturers continue to look out for the next trend. In this case, the biofuel industry is on the horizon.

“The big trend that is expected to affect the composting equipment industry is the proliferation of biofuel production and the large amount of spent-grain material that will require some type of reuse or disposal,” Bryan-Brown noted.




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