With odor climbing near the top of things dairymen should regulate, the Patz Corporation developed a way to zap it from a dairy’s list of concerns. Its new OZy manure treatment system released in August uses electricity to treat manure prior to storage or land application. Manure with less than 8 percent solids is drawn from a storage vessel into the machine.

There, it flows through three electrical reactor tubes where electrical pulses kill the odor-causing bacteria and pathogens. The manure is then pumped back into storage, explains John Hoffner, OZy product manager for Patz.

“I was very skeptical that it would reduce the odor,” says Pat Brusky, a dairy producer from Wisconsin. “It wasn’t completely odor-free, but it was drastically reduced. Before, if you got flush water on yourself the smell would linger for a long time. Now, you just wash it off and can’t even tell.”

A portable model was developed for research and geared for the custom manure applicator wanting to treat manure at various locations. The electrical unit is powered by a diesel generator with a 100-gallon external fuel tank.

After rounds of testing on dairy and swine operations, Hoffner found that the optimal results were seen 10 to 30 days after treatment and producers wanting to see the maximum benefit should apply manure in that window. After 30 days, bacteria from the fresh, untreated manure added to storage throughout that time can begin to produce a noticeable odor.


Farms wanting continuous treatment – processing manure prior to long-term storage – can purchase a stationary model that runs off an on-farm 220-volt, three-phase connection. Operating costs of this model are about half that of the portable unit.

“The ideal scenario is to treat manure as it is coming out of the barn so every drop is treated,” Hoffner says.

The first stationary model was installed this month and without a real-world example, Hoffner could not speculate as to how long pre-treated, stored manure will hold the benefits of this treatment, but he did say samples in the lab have maintained low bacteria and odor levels for two years.

When properly installed, the OZy grounding process removes the possibility of stray voltage and does not provide any electrical hazards to the equipment, farm, people or animals.

Both units can process up to 100 gallons of manure per minute or 144,000 gallons per day.

On-farm testing at 16 dairy and swine facilities in Iowa, Pennsylvania and Wisconsin revealed a 70 to 80 percent reduction in bacteria. This technology is successful at reducing coliform and E. coli levels and alleviates the concern of surface and groundwater contamination. It also helps with reassurance of fertilizer for fresh produce or feedstuff crops.

The electrical pulses also break down organic matter, encouraging the settling of solids. Phosphorus settles with the solids, thus enhancing the farm’s ability to manage nutrients in the manure.

An unexpected benefit was discovered while testing the system at Brusky’s flush barn near Pulaski, Wisconsin.

Brusky separates the manure on his 70-cow dairy. The solids are land-applied while the liquids are pumped from the lagoon through irrigation lines on his hay fields. His recyclable flush system pulls flush water from the top of the lagoon to wash the alleys of the freestall barn.

“I stumbled upon it,” Brusky says of how using the system resulted in lower somatic cell counts. “In the summer (the SCC) dropped real low when it usually peaks. The only thing we changed was what we did with the manure.”

The liquids were treated and pumped back into storage after running through the electrical pulse system. The flush silo was then filled with liquids that had a much lower bacteria count. Since the cows walk in the flush water, cleaner water means cleaner cows.

Just after one treatment, the dairy had fewer cases of mastitis and a lower SCC, enough to lower treatment costs and qualify for a milk premium. After a second and third treatment the results were the same.

“The animals were exposed to a cleaner environment,” Hoffner says.

“That’s a benefit to me. It’s more of a benefit than the odor,” Brusky adds, noting he doesn’t have many neighbors that have expressed concerns about odor.

Hoffner sees this technology as a benefit to the industry, but worries the size limitations at this point may hinder it from mass implementation. Farms creating more than 144,000 gallons of manure a day would need to purchase more than one unit. The processing capabilities could also limit the number of farms a custom applicator can service.

In addition, he’s only worked with dairies and swine farms to date and hasn’t had the opportunity to process manure at higher solid levels.

Hoffner imagines this technology could go beyond agriculture and prove to be useful in municipal and commercial wastewater treatment.

He says the company is continuing research to fully understand all the benefits this technology has to offer. He was hoping to obtain crop yield data this year from fields fertilized with treated slurry. However, the weather left corn standing too long in the field to gather results.

Although there’s more to be done, Hoffner says this system has already been proven to do as it was originally intended – to reduce odor and pathogens and to better manage nutrients.

As regulations and restrictions continue to increase, Hoffner sees this system as a tool to better manage nutrients and control odor emissions. And it’s tough to put a price point on the unforeseen. PD

Ask yourself:

  1. Does the manure on your dairy produce an odor?
  2. Is your farm’s odor a concern for your neighbors?
  3. Is odor a concern to the regulators in your state?
  4. Do you handle manure with less than 8 percent solids?
  5. Does your dairy have 220-volt, three-phase power available?
  6. Are you looking to treat manure without the use of additives or chemicals?
  7. Are you concerned about pathogen transfer through manure?
  8. Do you have a flush system using recycled barn water?
  9. Are you a custom manure hauler looking to add a benefit to your services?
  10. Would nutrient concentration help you better manage your soil fertility program?

If you answered yes to seven or more of these questions, this technology may be one for you to consider.

Karen Lee