|
 |
|
Farm Bill Funded Project
Green Valley Dairy
| Location |
Krakow, Wisconsin |
| Project Type |
Farm Scale |
| Animal Type |
Dairy |
| Population Feeding Digester |
2,100 |
| Baseline System |
Storage Lagoon |
| Digester Type |
Complete Mix |
| System Designer |
Biogas Direct, LLC |
| Biogas Use |
Cogeneration |
| Generating Capacity |
600 kW |
| Receiving Utility |
WE Energies, Inc. |
 |
Photo: Energy Center of Wisconsin
|
Green Valley Dairy installed two above-ground, complete mix digesters to treat the 83,000 to 105,000 gallons of manure that are produced each day on their farm. Co-owner Guy Selsmeyer said the digester has had very good biogas production and has generally produced more biogas than the farm could use.
To increase digestion, manure is preheated using a remote heat exchanger and fed continuously into the digester. Biogas is dehumidified using a condensate trap and chiller with added oxygen and burned to generate electricity and heat. Green Valley Dairy established a sell-all contract with We Energies, who buys the electricity produced at the farm. All recovered heat from the digester is used to maintain a digester temperature of 102°F and excess biogas is flared. The farm also has a backup boiler to heat the digester, which is important because the dairy uses solids for bedding.
Green Valley Dairy's digester project includes the following benefits:
- Odor and pathogen reduction
- Electricity and heat production
- Digester effluent utilized as organic, generally pathogen-fee nutrients for fertilizer use and animal bedding
A solids separator is used to separate solids from digester effluent. The farm produces approximately 120 tons of biosolids per week using half for on-farm bedding and selling the rest to neighboring dairies. Green Valley Dairy plans to expand and add a third digester and second generator.
Before we installed the anaerobic digester, we were handling manure as a waste product when what we should have been doing is handling it as a value-added product.
—Guy Selsmeyer, Co-owner, Green Valley Dairy
|
