The main brewery waste is spent grain. Other process waste is yeast.
There are two alternative ways to process beer spent grains: drygrains or biogas.
It was considered that drying spent grain is cheaper than a biogas plant. However, brewery dried grains compete with the fresh grain. When there is grain overproduction on the agricultural market, grain has a low price. And dried grains are difficult to sell, and drying is unprofitable. Drying is just a way to get rid of waste.
Spent grain recycling into biogas is considered mainly for a purpose of the natural gas replacement in the brewery boilers
With the direct replacement of natural gas by biogas in boilers, the capital costs for a biogas plant are lower because there is no need to buy a generator or methane upgrade.
Investment in a biogas plant without the power generation can be compared to an investment in the grain drying.
A biogas plant is ultimately a more economical option than the spent grain dryer. The payback time for such a biogas project in the prices of 2023 is 2-3 years. Unlike drying, biogas plants don’t consume but rather produce energy.
Comparing the payback time of a drying plant to that of a biogas plant, it is correct not only to count the direct benefits of the produced biogas but also to count natural gas savings from not drying spent grain.
It should also be remembered that a biogas plant allows the brewery to achieve decarbonization and sustainability goals.
Dryer or biogas plant?
Zorg Biogas has built biogas plants for a wide variety of substrates: distillery wastewater, carrot pulp, sugar beet pulp, corn silage. These types of raw materials are similar to spent grains. Also Zorg Biogas did lab test of spent grains. That's why Zorg Biogas is able to build a biogas plant on spent grain.
In addition to spent grain processing in biogas reactors, breweries also have projects of the utilisation of the biogas, produced by wastewater treatment plants. Zorg has designed and supplied gas treatment equipment for several well-known beer brands
To calculate your offer for a biogas plant, please fill out a questionnaire for breweries.