Using biological treatment to improve Concentrated Animal Feed Operation (CAFO) waste handling

Much of our animal based foods come from CAFO systems where animals are housed at high density. WIth the high density comes problems with manure and urine. The number and size of these operations means that CAFO can be the largest source of wastewater in many areas. The waste is high in BOD5 and ammonia which is often treated in lagoon based systems with land application via irrigation systems. Odors and treatment inefficiencies in ponds can cause problems with operations, so there was room for improving biological treatment processes.

As this is an ongoing R&D project, I thought this would be a way to introduce you to how biological products are developed for new applications. We started with a manure degrading formulation developed in the 1990s but knew that advances in our technologies could improve the results. Working with several groups on introducing biological pretreatment in the animal houses, we are using extensive analytical testing in both pilot scale and working houses. Testing includes standard water chemistry tests and DNA based testing for changes in the biomass composition. The goals for adding biological products being:

• Reduce difficulty in pumping manure from collection pits to wastetreatment lagoons
• Lower noxious gases inside buildings - this includes H2S, ammonia, and odor causing VOCs
• Control dense crust formation which intensifies files and other nuisance insects
• Start biological degradation upstream of the waste treatment lagoon thereby reducing treatment time required in the lagoon system

We noticed that many biolgoical additives were being marketed for CAFO and manure treatment operations and I had worked on manure treatment products years before without much scientific testing. So we started at the begining and looked at the differences in feeds, bedding (if used), and operation protocols. By learning where and why bottlenecks occur, we were able to see opportunities to modify the biomass and enzymes present. In the past, we assumed that Bacillus strains associated with plant based waste degradation were sufficient and used well known waste degrading Bacillus spores. They worked, but there was definitely room for improvement. We also did not limit ourselves to bioaugmentation technologies. The research aslo considred the use of micronutrients, enzymes, or other supportive chemistries also enhance pre-treatment. Here is what we have discovered and are continuing to evaluate:

• Pretreatment in animal housing is a cost-effective option
• Systems with straw bedding benefitted from adding a newly isolated high cellulase producing organism.
• The inclusion of biosurfactant and high cellulase strains improved manure liquefication which was the primary bottleneck in the pre-treatment system.
• Adding enzymes did improved the results
• The use of dry cultures immobilized on biosupportive carrier allowed for the inclusion of vegetative organisms for performance in lower temperatures and improved removal of H2S and other odor causing compounds
• The appropriate solution depends upon animals housed and other local conditons so there was no universal product

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