Wet and sensitive residues
Brewers’ spent grain and yeast have limited storage stability. Their use as feed depends on buyers, logistics and hygienically reliable handling.
Process solution for breweries
Biogas from brewers’ spent grain and brewery waste
Brewers’ spent grain, press liquor, spent yeast and other brewery residues are converted through anaerobic digestion into biogas, renewable heat, power, cooling and organic fertilisers. This can reduce external energy demand and operational carbon emissions.
Initial situation
Typical challenges in brewery waste management
High energy and disposal costs
Brewing requires continuous heat, power and cooling, while non-marketable residues and wastewater sludge generate additional costs.
Process inhibition by nitrogen and sulphur
Protein-rich brewery residues can cause ammonium and hydrogen sulphide to accumulate in the fermentation system and impair biological stability.
Wastewater and odour load
Production wastewater, interim storage and residue transport can constrain production expansion and cause odour and traffic impacts.
Process principle
From spent grain and spent yeast to biogas, energy and fertiliser
Collect and suspend residues
Brewers’ spent grain, press liquor, yeast, filter aids and suitable wastewater sludge are combined with process water and, where required, high-dry-matter co-substrates to form a pumpable biosuspension.
Aerobic hydrolysis
The biosuspension is hydrolytically pretreated with air. This opens up lignocellulosic structures and prepares the material for subsequent methane formation.
Multi-stage anaerobic digestion
A robust adapted microbial culture is retained in hydraulically and only partially mixed main digesters. Secondary digestion increases degradation and supports hygienisation.
Treat and utilise biogas
The biogas is desulphurised, dried and, where required, compressed. It can be used for combined heat and power generation or further gas utilisation.
Recover nutrients
Phase separation produces solid organic NPKS fertiliser and biofiltrate. Ammonium and sulphur compounds are removed in a controlled manner and recovered as liquid fertiliser concentrate.
Recycle process water
Treated biofiltrate is returned as process water for biosuspension preparation. Surplus liquid streams can undergo further treatment.
Suitable feedstocks
Brewers’ spent grain, spent yeast and other brewery residues
Brewing residues
Brewers’ spent grain, press liquor, spent brewing yeast and organically loaded filter aids.
Wastewater-related residues
Sludge from on-site aerobic or anaerobic wastewater treatment.
Suitable co-substrates
For example malt dust, cereal chaff, mill and brushing dust, or comparable biogenic residues with a high dry-matter content.
Client benefits
More value from on-site residue streams
Lower process energy costs
The produced biogas can cover a substantial share of the brewery’s heat and power demand and reduce dependence on fossil energy.
Greater disposal security
The brewery becomes less dependent on the short-notice collection of wet spent grain and fluctuating feed markets.
Additional value products
In addition to energy, the process generates organic NPKS fertiliser and liquid nitrogen/sulphur fertiliser concentrates as potentially marketable products.
Less wastewater, odour and transport
Integrating sludge and process water can reduce wastewater load. At the same time, interim storage, odour emissions and plant-related truck traffic are reduced.
Potential carbon revenues
Verifiable reductions in fossil energy use and greenhouse-gas emissions may, depending on the applicable scheme, create additional revenue potential.
Stronger sustainability positioning
Using on-site residues for renewable energy and circular products supports decarbonisation and credible sustainability communication.
Technical background
The presented process solution is based on the German patent specification DE 10 2014 001 907 B4. The specific technical and commercial design must always be tailored to the project, site and material flows.
Your brewery project