Vogelsang Biogas Case Study

RotaCut Macerator Outshines Grinder at Green Cow

Problem Summary:
Green Cow, an energy producer in Goshen, Indiana uses manure to generate biogas and other byproducts. To optimize efficiency of the digestion process, solid particle size needs to be consistent around 4-5mm (3/16”). The grinder being used by Green Cow was producing stringy waste that did not meet this requirement and often caused clogs. It turns out that it was the wrong equipment altogether.



Solution Summary:
Vogelsang RotaCut RCX58G; 10-inch flanges; standard 34mm screen, 20hp TEFC motor


The Customer:
Green Cow Power in Goshen, Indiana takes in manure from five nearby dairy farms – that’s three semi-trailers full every day. The manure, combined with area food waste, is fed into a biogas digester to produce 630 SCFM of biogas and 2200 kW of electricity that is used in the local power grid. The digested liquids and solids are returned to the farms.

The liquid is stored in lagoons to be used as a crop fertilizer, while the solids are used as cow bedding. Hot water that is generated is used to power the digester.


The Problem:
A twin-shaft grinder from a Vogelsang competitor was being used to reduce manure solids before they entered the pumping process. The high volume of the flow and inconsistent solid contents in the manure would routinely plug up the grinder which caused it to need frequent servicing.

Due to the design of the grinder, replacing the cutter stack and lower bearings was very time-intensive and expensive. Rebuilding the cutter stack required aligning and shimming numerous blades and spacers, an operation that could take hours. Additionally, the twin-shafted grinder was not designed to separate the heavy solids like rocks that get into the manure. The feedstock also contains very stringy fibers which could not be handled by this equipment or cut into the required 3/16” size to maximize digester efficiency.


The Solution:
The Vogelsang RotaCut RCX58G is an inline macerator used on the suction side of the submersible pumps that feed the manure/organics mixture into the anaerobic digester tank. The RotaCut design separates the heavy solids including a high volume of gravel and rocks and drops them into a pit. The RotaCut screen then reduces the remaining material into particles of the required size.


Advantages of the Vogelsang Solution:

  • No plugging due to different solids particle reduction technology and integrated heavy solids separation
  • Low cost of service and repair

Benefit for the user:

  • Increased efficiency of biogas plant
  • On-site maintenance and easy screen and blade replacement
  • Consistent, defined particle size for optimized digestion



It’s a wet macerator and a heavy material separator in one. The RotaCut reliably separates heavy objects like stone and metal, allowing them to drop into a separator bin, while macerating fibers, stringy and coarse material into uniform particles. This is especially helpful if you are supplementing your feedstock with corn and grass silage.

The RotaCut RCX Series macerator is used on the suction side of submersible pumps that feed manure into the anaerobic digester tank. It can also be used at the point of recirculation to further refine sludge.

Standard RotaCut features include:

  • AutoReverse
  • Auto Cut Control (ACC)
  • Self-sharpening blades
  • Reversible cutter screens
  • RotaCut is 100% rebuildable inline

RotaCut reduces your cost of service and repair. There are no cartridge-style parts that have to be sent out for reconditioning or factory refurbishment. The RCX model features a quick release door allowing access to the cutting head. All RotaCut screens are reversible to allow for a fresh cutting surface without buying a new spare part.

Typical routine service such as changing blades or flipping the reversible cutting screen takes only a fraction of time required to service a typical twin-shaft grinder

Adapt RotaCut to your operation using one of several pattern cuttings. Screens come in several patterns that will produce a designated size solid. The rotational speed of the cutting head also influences the solid size. The examples shown will produce different solid sizes and are easily interchangeable should operating conditions change. Screens are available in several material options for high wear applications. See RotaCut Models



Watch on YouTube

Video Demo: RotaCut In-line Macerator

Heavy debris removal and consistent cutting

Reliably macerates fibers in liquid media - prevents floating layers



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