A DVO system can recover nutrients from digested waste to be used as fertilizer. When the nutrient recovery system is used, we remove ammonia/nitrogen through volatilization.
DVO’s Nitrogen Recovery process captures nitrogen ammonia that is otherwise lost, and places it in the form of a stable commercial fertilizer. This creates another revenue source (or operating cost offset) for the digester.
When ammonia is separated it still leaves solids behind. These solids are then separated with both coarse- and fine-screen separation systems.
After nutrient recovery, solids settle extremely fast, and liquids at the top of a settling tank are exceptionally clean. Removing the solids takes out a large percentage of phosphorus and a smaller percentage of potassium fertilizer. This removal breaks the recycle buildup effect of P and K.
If this removal is still not enough, then we have had success (primarily with mixed substrate digesters that take in a lot of protein type material) with using dissolved air floatation (DAF) removal that does a very good removal percentage.
We have not found it necessary to utilize fresh water if we utilize some of the above steps to separate and settle/float the solids from the digested and ammonia removed liquids.
Poultry Litter Digestion
A DVO digester offers the unique ability to digest poultry manure on a belt-collection system where no bedding material is utilized. Our system:
- Works without outside waste material additions.
- Operates with little or no fresh water – egg wash water is sufficient.
- Utilizes scrubbed and recycled effluent liquid from the digester for dilution of the influent waste stream. Produces an economical, beneficial and stable nitrogen fertilizer from the odorous ammonia that is normally volatilized into the atmosphere.
- Significantly reduces odor from the poultry facility and its waste.
A DVO system in operation at a 1.2-million-layer family farm in Ohio digests poultry litter, feathers, mortalities, and egg wash water.