As sawdust supplies in the U.S. grew tighter, dairymen found it to be an expensive, and sometimes non-existent, bedding material.

A Lynden, Washington-based company saw producers struggling to find bedding for their cows and developed an affordable system using proven science that was developed in the industrial field.

The BeddingMaster from DariTech, Inc., is a rotary drum composter that takes an available on-farm commodity and converts it into a reliable source of bedding.

While visiting with Steve Peerce, DariTech, Inc., at World Dairy Expo, in Madison, Wisconsin, he explained what makes this composter unique and how it will fit into an existing operation.

In some portions of the country, composting easily occurs in simple outdoor windrows. However, in wet climates like Washington State, that is nearly impossible. Some have tried putting the windrows inside a building but Peerce said there is still too much moisture in the air for it to work properly. Therefore, they looked into a fully contained system to operate within even the harshest climate.

“There’s a long history in industry of rotating drums,” Peerce said. However, they weren’t affordable for dairies. “We don’t need to make fully mature, finished compost.”

The goal is simply to kill the pathogens so there is no regrowth of bacteria. In this system, scraped manure, or dewatered flush manure, from a dairy or swine operation is fed directly into an EYS Separator specially designed by DariTech, Inc., to provide the ideal feedstock for the composter, which is made up of manure solids at a minimum of 35 percent dry matter, with 37 to 38 percent preferred.

Liquid effluent is sent to storage while the separated solids are fed into the composter by passing through the fixed opening in the entry end. The solids contain the aerobic bacteria that will consume the organic matter also present.

This composter can also be fed digested solids on the back end of a methane digester. A blower pulls air through the drum from the end back to the beginning, ensuring an ample air supply. To not short-circuit the air flow, fresh solids are added into the unit below the solids line already established in the drum.

The air mixes with the solids and within just a few hours the activity of the bacteria has brought the temperature to over 150°F where it stays as the material moves through the drum like a plug. To maintain the continuous process and the appropriate level of bacteria the drum must be fed at minimum 18 hours per day.

The insulated interior of the drum reduces heat stress and abrasion on the steel. It also allows the moving parts to remain at an ambient temperature instead of trying to operate in the heat from the compost. The ends of the unit are fixed to the frame and the drum rotates around each end.

Therefore, the exit hole can be positioned near the top of the drum instead of the center like most units. With a higher exit station, the drum can be filled to 75 percent capacity, increasing throughput by more than 50 percent, Peerce explained.

“We’re always looking to increase value,” he said. “By increasing capacity somebody may not have to buy the next-larger unit. With a smaller drum they can save money.”

The BeddingMaster is available in three sizes – 6x16 feet, 6x32 feet and 8x40 feet. The 6-foot diameter units can fit on a standard size trailer, while the largest drum needs a bigger trailer with “wide load” signage but no pilot car, keeping delivery fees at a minimum.

Including the purchase of a separator, the 8’x40’ unit is priced at $290,000, the 6’x32’ at $200,000 and the 6’x16’ at $150,000. Farms that already have some type of separation system will only need to purchase the composter, Peerce said.

If more composting capacity is needed an upgrade in size or the addition of a second composter is required. Other rotary drum composters are designed to simply add on a new section, but Peerce explained that system will eventually cause a bowed effect on the equipment.

Once put into action, employees at DariTech found that one drum beds a lot more cows than they originally thought. The input from one cow can provide enough bedding for one and one-half to two stalls for deep beds and will go farther on mattresses.

It also stays in the stalls better than sawdust, Peerce reported. Because of the excess material some dairies will opt to not compost all of the manure or will do so and sell the excess compost as bedding or to the horticulture market.

According to Peerce, of the 14 units in use today, all of them make more than they need. It usually takes about three days to move through the composter, but once discharged it can be used immediately for bedding or stored in piles until needed.

The BeddingMaster can help remove the uncertainty as to when the next load of bedding will arrive or the maintenance issues associated with sand.

“You’ve got your next load of bedding and as much of it as you need,” Peerce said. ANM

YOUR RESULTS
Are you ready for composted bedding at your facility?

The following checklist can be used to determine if this new technology might be a fit for your operation.

1. Are you at risk of losing your current bedding supply or wish it were easier to work with?
2. Are you interested in reducing the amount of bedding material that ends up in your fields?
3. Are you looking at separating solids from your effluent system?
4. Does your climate prevent you from outdoor composting?
5. Do you want to continue processing the solids from your digester?
6. Are you looking for an added benefit from your manure?
7. Do you have space for a compost rotary drum at your facility?
8. Do you see your manure management as an area of potential income for your facility?

If you answered yes to five or more of these questions, this technology is one for you to consider.