Smooth moves help separate good from bad

The demand for pork, combined with stringent environmental regulations, has turned Holland into a hotbed of hog manure management innovation.

After seven years in the business of selling garden compost processed using a tunnel composter, entrepreneur Hans Hendrix set his sights on the lucrative hog slurry processing scene. His research guided him to invent the AgraSEP system, which uses a unique arrangement of vibrating screens to separate solids from liquids.

Agra-Gold consultants from Manitoba visited a 330 sow to weanling farm where Hendrix was running one of his unusual mobile systems. The farmer wanted the AgraSEP to extract enough solids from the manure to constitute 25 percent of the phosphorus. The farmer found it was easier to sell extracted solids than it was to sell raw manure. The solids coming out of Hendrix’s machine contained 55 to 66 pounds of phosphorus pentoxide (P2O5) per tonne.

The raw slurry was stored in pits under the barn. Although the age of the manure ranged from fresh-that-day to eight months old, it was agitated to create a homogenous slurry mixture that was pumped up to a hopper at the top of the AgraSEP trailer.

Gravity drops the slurry down to the first vibrating screen, which is 500 microns. Liquid falling through the top screen lands on the second stage, which sports a 70 micron vibrating screen.

Solids dance along the screens until they fall via gravity into a hopper that drops them into the screw press. The vibrating screens alone have already brought these solids down to a consistent dry matter content of 14 to 17 percent before they enter the screw press. The screw press has a 250 micron filter to remove more liquid and bring the dry matter content to 26 or 27 percent.

Liquid coming out of the screw press is pumped back up to the front of the line to go through the system again. Hendrix feels that with work, his system is capable of removing 35 percent of the P2O5.

The system Hendrix sells to farmers has a capacity of 5,500 gallons per hour and sells for $100,000. He is developing a larger unit with four vibrating screens and two screw presses, and a capacity of 22,000 gallons per hour. It will sell for $300,000.

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