Waste is only waste if you simply cannot set it to excellent use! EU-funded researchers have developed a circular price chain deriving money sustainably from wet straw, biogas digestate and identical residues, via goods these as fertiliser, gasoline pellets and mushroom substrate – and boosting energy generation in the approach.


© gerasimov174 #262946677, resource:inventory.adobe.com 2020

The EU-funded circular economic climate job MUBIC centered on the transformation of very low-price agricultural waste into large-price products – one of which is employed to develop mushrooms, whose cultivation the companions set out to revolutionise.

More exclusively, this product is a new sort of mushroom substrate, the materials on which the mushrooms are grown. ‘Along with other outputs, these as gasoline pellets, fertiliser, and pre-addressed feedstock for quicker biogas output, the approach formed in MUBIC also provides significant sustainability gains,’ claims job coordinator Peter Damgaard Nielsen of Danish SME Advanced Substrate Technologies (AST).

It notably increases the biogas generate from agricultural wastes like straw or horse bedding by about 30 %, via the prior chopping and grinding of this biomass. The ability to approach wet straw, meadow grass and identical materials is a individual moreover level: the MUBIC approach for these demanding kinds of feedstock also requires pretreatment with nitrogen to break down the lignin in the stalks, Nielsen describes.

Profitable, circular, environmentally friendly

‘Using this approach, you get additional biogas and you get it quicker, mainly because the bacteria in the biogas plant can also use the lignin as feed,’ claims Nielsen. The nitrogen employed for this pre-cure is recovered from the biogas plant, via the cure of the digestate – the residues of the feedstock.

The nitrogen is extracted from the digestate in services created as annexes to the biogas vegetation themselves. As of July 2020, operations have begun at the first these insert-on plant created as a industrial facility, in accordance to Nielsen.

In the MUBIC model, the digestate may well, in actuality, have started off out as biomass equipped by the companions. ‘Our lorries consider feedstock to the biogas plant and digestate back to the insert-on plant, wherever we dry it,’ Nielsen carries on.

The addressed digestate is then transformed into a assortment of goods. Alongside with the mushroom substrate, these outputs include gasoline pellets that are considerably additional sustainable than competing goods mainly because they are derived from a sort of waste and mainly because this waste is a residue of domestically sourced biomass.

The MUBIC approach provides a pelletised substrate whose dry make any difference articles, at 85 %, is a great deal better than that of traditional substrates, which normally typical about 30 %. As a result, MUBIC substrate provides considerably additional mushroom feed for each cubic metre than competing goods, Nielsen describes. Thanks to its large dry-make any difference articles, it can be saved and does not need cooling all through transport about for a longer period distances – as opposed to traditional substrates, which may well commence to rot.

MUBIC’s substrate enhances a further innovation developed in the job: a system by which mushrooms grown on trays shift previous pickers on a conveyor belt, as opposed to pickers possessing to shift via the cabinets in mushroom farms. This individual innovation was perfected by Dutch SME Panbo Programs, the second spouse concerned in the job, as a way to lessen harvesting prices.

Rooted in wet straw

MUBIC, which finished in January 2020, was funded via a Horizon 2020 programme exclusively created to help SMEs get ready their improvements for commercialisation. Without the need of this aid, the straw-to-substrate concept would have been shelved, claims Nielsen, who emphasises that the funding enabled the companions to convey their concept to lifetime.

AST experienced to begin with considered promoting full insert-on vegetation, but inevitably made the decision to focus on the goods generated all over the approach in its place: money is generated at a number of methods, from raw materials that is largely obtainable for cost-free.

Expended substrate from mushroom output is one these residue, and a excellent illustration of the proposed circular strategy. In MUBIC, it is recovered as feedstock for the output of biogas, and the digestate left about from this approach is employed to make fresh substrate.

The two the new mushroom cultivation system and the several goods from MUBIC’s circular price chain have been satisfied with interest, with new partnerships enabling the job companions to consider these developments forward, Nielsen concludes.