A Reliable Feed

Having a reliable and constant feed of digestate is crucial for the economical and efficient operation of a biogas plant. The supply of suitable solid material can increase the gas yield and reduce the amount of energy needed to power operations such as stirring, agitating or pumping.

It may sound simple, but failure-free digester feeding presents a considerable challenge to technology. Raw materials, for instance, contain stones and sand that can increase wear and malfunctions. As the variety of raw material grows every year it becomes increasingly important to choose a feeding technology capable of processing material that is difficult to convey.

Introducing Vielfraß®

The Vielfrass® solid material feeder unit is based on these requirements and was developed to process organic raw materials, grass silage, solid dung and similar bio products. Vielfrass® has two counter-rotating screws that evenly distribute and mix the digestate. These feeder screws introduce the digestate into the upper part of the digester enabling a high output without the need for high pressure. An interval controller ensures a uniform and trouble free feeding process.

The Vielfrass® system includes extremely robust, safe and low-maintenance stainless steel components with all parts prone to corrosion made of V2A stainless steel for ultra-long durability.

Flexible feeding technology thanks to type variants

The selective feeding of the fermentation process is based on the principle of flexible dosing. By installing expansion modules, the Vielfrass® standard version, developed to suit the needs of small plants in particular, can be used for larger plants and additional feeding options.

A Flexible Approach

Flexibility is at the heart of Vielfrass®. Simply by adding additional modules the standard version, developed to suit the needs of smaller plants, can be used in larger installations with additional in feed options.

Vielfraß® FA
For optimum digestate separation

The heart of Vielfrass® FA consists of a stationary in feed unit with a cutting attachment containing three additional rotary grinders.  By maintaining a consistent cutting action the complete separation of the digestate being carried is ensured, with the likelihood of winding reduced. After consistent thorough cutting, the feeder screw introduces the now processed digestate into the digester.

Vielfraß® Top
Top In-feeding

Vielfrass® Top is specially designed to allow in-feed of digestate into the top of the digester.


For both variants, the feeder volume of in-feed can be increased to 40m3.


The benefits are

  • Perfect for the processing of solid dung, grass silage and other bio products
  • Energy-saving with maximum separation of digestate
  • Option to increase in feed volume
  • Controllable in-feed using automatic timer control (or by optional weighing facility)
  • Low maintenance due to high-quality stainless steel components
  • Robust feeder screw for reliable in-feed

Screening of stones and other detrius prevents wear.

Why not call us for more details?
Tel.: +44 121 374 2610
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icon pdf Vielfrass® - The Biogas component: Solid material feeder unit