Knowledge Base

Biogas plants are divided by the feedstock they process and the scale at which they run. HoSt builds four main types: manure biogas plants, agricultural biogas plants, industrial biogas plants, and sludge biogas plants. The boundaries are practical rather than strict, because most modern plants co-digest several feedstocks at once. What they share is the same core process, anaerobic digestion, and the same starting scale at HoSt, from 20,000 tonnes of organic input per year.

Manure biogas plants: from compact farm systems to large-scale digestion
Manure biogas plants digest livestock manure, with or without additional co-substrates. At the compact end of the scale, HoSt’s Microferm is designed for individual farms with a manure output from 7,500 m³ per year. It operates fully automatically and requires minimal operator attention. Larger manure plants process higher volumes and can be configured to produce biomethane for grid injection or bio-CNG for transport. Manure digestion has the added benefit of reducing methane emissions that would otherwise arise from open manure storage.

Agricultural biogas plants: managing difficult feedstocks
Agricultural biogas plants process a wider mix of substrates alongside manure, including grass, straw, maize silage, chaff, agricultural by-products, and other farm residues. HoSt designs these plants with advanced feeding and mixing technology capable of handling viscous and fibrous materials that would destabilize a less robust system. The concrete digester tanks, fitted with slow-speed paddle mixers (HoSt GiantMix) and propeller mixers, maintain process stability even at high organic loading rates. This configuration allows operators to use lower-value substrates such as straw rather than energy crops, which is both economically and environmentally advantageous.

Industrial biogas plants: processing organic waste streams without manure
Industrial biogas plants digest organic waste from food processors, breweries, slaughterhouses, the fats, oils and greases (FOGS) sector, and other industries. Unlike agricultural plants, they operate without the addition of manure as a process buffer. HoSt has constructed numerous systems for slaughterhouse waste, including thermal pressure hydrolysis (THP) pre-treatment for category 2 animal by-products, which improves conversion rates for difficult material. Sanitation of category 2 waste is also included in our scope. Industrial plants also manage unpacked food products and liquid waste streams and are designed to maintain stable digestion despite the variability of industrial waste compositions.

Sludge biogas plants: turning wastewater treatment into energy generation
Sludge biogas plants are built at municipal or industrial wastewater treatment facilities to digest primary and secondary sewage sludge. HoSt applies a combination of thermophilic (around 55°C) and mesophilic (around 40°C) digestion stages to increase energy output and reduce the volume of sludge requiring disposal. This converts what is otherwise a costly waste management obligation into a source of renewable energy and lowers the carbon footprint of wastewater operations.