Nearly 200 people from 31 states and two provinces attended the Midwest Manure Summit in Green Bay, Wisconsin, at the end of February. Hosted by the University of Wisconsin Extension, the summit covered all things manure, from application and regulations to processing and odor. Various separation and nutrient recovery technologies were discussed.
This year a special pre-conference session was held strictly focusing on anaerobic digesters. The day included presentations on operating anaerobic digesters and how to optimize these systems.
It also featured an operator panel with Brian Langolf, who oversees three anaerobic digesters for the University of Wisconsin – Oshkosh, and Grant Grinstead, co-owner of Vir-Clar Farm Power LLC, a complete mix system on a dairy near Fond du Lac, Wisconsin.
The summit concluded with farm tours at Wayside Dairy LLC and Pagel’s Ponderosa Dairy LLC.
Wayside Dairy is owned and operated by the Dan, Paul and Jeremy Natzke families in Greenleaf, Wisconsin. With 1,800 cows on sand, Paul Natzke says the dairy opted for a sand separation system to remove copious amounts of sand from entering its manure storage.
In this system, which was installed around 10 years ago, a shuttle unit pulls “boats” filled with sand-laden manure from the main three barns to a separate building with the separation system. It lands in a central collection pit where it is agitated prior to being pumped to the first sand separator.
A second separator was added when the farm expanded. The system now processes 60,000 gallons of manure each day. A Penn State shaker box was also a late addition to the system in order to remove excess moisture from the sand before it is stacked.
Natzke says mechanical separation was chosen over a gravity system due to odor and footprint concerns with sand lanes.
He reports the farm is recovering 85 percent of the sand from its manure. The system runs 21 hours a day and requires 12 to 14 hours per week of maintenance.
The person in charge of bedding moves the sand piles in and out of the indoor storage area, depending on the season. On average, the sand sits for two days prior to going back into the barn.
John Pagel purchased the 67-cow family farm from his parents in 1980. Pagel’s Ponderosa Dairy in Kewaunee, Wisconsin, now milks 5,000 cows and Pagel’s four children are involved in the farm. In 2008, Pagel installed an anaerobic digester to minimize odor, create a bedding source and produce electricity.
Manure is collected from the barns and sent to a holding tank before entering the 3.2-million-gallon digester, where it sits at 101ºF for 10 days. Methane is collected and burned to generate electricity.
The manure effluent from the digester is separated in a screw-press separator. A dryer was added to further dry down the solids. Previously, the solids had 70 percent moisture.
With the additional drying phase, they are now at 45 to 50 percent moisture. The dried solids are used in deep-bedded stalls on the farm. The liquid from the separator is pumped to lagoons and field-applied in the spring and fall. PD
PHOTOS
PHOTO 1: The anaerobic digester at Pagel’s Ponderosa Dairy holds 3.2 million gallons of manure and provides enough electricity for 1,000 homes.
PHOTO 2: Attendees of the Midwest Manure Summit farm tours look at the dryer used to remove moisture from manure solids at Pagel’s Ponderosa Dairy.
PHOTO 3: One tour attendee takes a closer look at the dried manure solids used for bedding at Pagel’s Ponderosa Dairy.
PHOTO 4: Two sand separators are used to remove sand from 60,000 gallons of manure each day at Wayside Dairy.
PHOTO 5: After viewing the sand separation system at Wayside Dairy, tour participants board the bus for driving tour of the farm.
PHOTO 6: With limited space indoors, some of the separated sand is stacked outside at Wayside Dairy to continue its drying process. It is brought back indoors to thaw prior to use as bedding in the stalls. Photos by Karen Lee.
Karen Lee
Editor
Progressive Dairyman
