Efficient substrate processing



BHS Biogrinder crushes and mashes organic domestic waste

BHS Biogrinder - Aus Biomüll wird Biogas EN.mp4

BHS Biogrinder crushes and mashes organic domestic waste

The BHS Biogrinder (type RBG) is used in the processing of biomass for biogas generation. The BHS Biogrinder is in use in southern Germany to crush and mash organic domestic waste. The upstream substrate processing speeds up gas production in the fermenter. Overall, the biogas plant operates more efficiently and reliably.



Fermenter-friendly processing

  • Enhanced uptake of nutrients for micro-organisms through intensive shredding, homogenization and defibration of the input material
  • Particularly effective in the case of highly fibrous biomass
  • Extraneous materials, such as soil clods and stones, are also crushed.

Greater variety of raw materials

  • Raw materials that were previously difficult or impossible to decompose in the fermenter can now be processed with ease after processing in the Biogrinder.
  • Wide range of applications: corn silage, grass clippings, green/organic/animal waste, sugar beet, corn straw

High energy efficiency

  • Very short substrate retention times
  • Nearly all the energy applied is converted into crushing capacity and not heat
  • Further energy savings result from the reduced need for chopping during harvesting, reduced agitator use in the fermenter 

Stable fermentation process

  • Homogenization facilitates transport of substrates
  • No deposits build up in the fermenter

Continuous process

  • Continuous operation simplifies technical integration of the machine into the overall plant 
  • Different sized Biogrinders available to ensure optimum throughput rates for biogas plant

Future-proof investment

  • High degree of flexibility when it comes to raw material selection in view of changing market conditions and legal frameworks

Technical systems



Feed opening

The Biogrinder has a large feed opening, which allows the machine to be easily fed with different materials.


The rotor is mounted on a vertical shaft. The material stream first connects with a distribution cone. Below this, the rotor has two levels, each of which can be fitted with a maximum of two pivot-mounted hammers. Crushing is carried out primarily between the rotating hammers and the stator strips on the machine casing. The arrangement of the hammers is variable, so that the rotor can be optimally configured for the specific task.

Distribution cones

The distribution cone feeds the inserted material to the hammer levels. This prevents possible clogging of moist or light material in the feed area.


 The carbide hammers welded onto the base are optimized to deliver a long service life. Due to the flexible bearing, even extraneous solid materials, such as stones and soil clods, can be crushed easily. Modification of the hammer configuration can be achieved in minutes.

Stator bars

The stator strips and wearing plates are fastened from the outside by means of bolts. The wearing parts can thus be easily exchanged and are optimized for long service life.


Discharge opening

The treated substrate continuously exits the processing chamber through a generously dimensioned discharge opening. A liner consisting of plastic plates prevents caking.


 Depending on the size, required throughput and desired crushing ratio, the Biogrinder is equipped with motors ranging from 37 to 90 kW.

Maintenance hatch

The Biogrinder has a large access hatch at the top to facilitate easy and quick maintenance or retooling.

Vibration damper

The machine is installed on vibration dampers to prevent the transmission of vibrations into the surrounding steel or concrete construction.


Designed as a technically reliable solution, the Biogrinder has a recirculating oil lubrication unit. This system is also used for cooling the bearings.

Key transfer system

In order to prevent uncontrolled access via the maintenance hatch, the machine is equipped with a key transfer system. The power supply is interrupted and the machine can be opened only by means of a special key after the rotor has come to a standstill.

Control unit

The Biogrinder can optionally be equipped with a control system. In the case of frequently changing input materials, it makes sense to implement a frequency inverter. In combination with the variable rotor configuration options, this allows for optimal coordination of the desired targets in terms of crushing results, throughput rate and power consumption.

Steel structure

As an option, customers can order a standardized steel structure for installation of the machine. It features a maintenance platform for the Biogrinder and a ladder.

Technical specifications

Performance data
Type Rotor Diameter Motor
RBG 06 780 mm 37 kW / 45 kW
RBG 08 1.000 mm 55 kW / 90 kW
Dimensions and weights
Typ 1) B C D E F G H Weight
RBG 06 416 mm 652 mm 210 mm 700 mm 1.565 mm 1.985 mm 1.050 mm 1.885 mm 2.000 kg
RBG 08 510 mm 750 mm 260 mm 780 mm 1.640 mm 2.450 mm 1.280 mm 2.010 mm 3.000 kg

1) Depending on the feed characteristics, data may differ from the information provided.

Technical specifications of customized models may differ from the data provided here. All technical specifications are subject to change due to continuous development. Subject to change without notice.




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Success stories

An environmentally friendly alternative to peat: The Biogrinder efficiently processes compost

February 2021
The Biogrinder from BHS-Sonthofen is successfully used by a cooperative in northern Germany for the production of an alternative to peat. A mobile plant with a control system from BHS Control Systems was implemented. The plant efficiently shreds surpluses of compost material and produces a substance that is suitable for use as an environmentally friendly alternative to peat. For example, the product is added to the production of potting soil to reduce the amount of peat contained in it.

First Biogrinder for India's biogas industry

December 2019
India generates a large amount of agricultural waste, including crop residues. As burning organic waste is considered to be a major cause of air pollution, the government of India has been offering incentives to mitigate the pollution problem and convert rice straw that is widely available in India into biogas. “Especially in northern part of India, rice straw will be an important raw material for biogas production”, says Neelesh Desai, Managing Director of BHS-Sonthofen India.

Biogrinder for biomass treatment plant

May 2019
The Association for Waste Management Kempten put a biomass treatment plant into operation in 2019. Technology worth about €2.8 million in total ensures that foreign matter is optimally removed from organic waste and green waste to prepare it for fermentation. A BHS-Sonthofen Biogrinder is now used to process and shred this material. Its low power consumption and exceptional shredding results, even for challenging input material, are what make it stand out.

Technical articles in the media

Efficiency in biogas generation

October 2020
BHS-Sonthofen has launched a new, completely redesigned version of the succesful Biogrinder on the market. The Biogrinder is used in biomass processing, where it ensures that biogas is generated efficiently and production is accelerated. The machine is now fitted with a disk rotor and stainless-steel components, making it stand out thanks to its improved durability and flexibility.
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