Biogas from grass clippings

Biogas is a mixture of various types of gases, largely methane and CO2. Biogas is produced by a process called “anaerobic digestion”, which is the bacterial fermentation – without O2 – of biomass that can include: agro-industrial waste, solid and liquid waste from livestock farms, sewage sludge, by-products from agriculture, the organic fraction of solid urban waste (OFMSW) and specifically-grown crops. Biogas enables the economical, sustainable and programmable production of energy, feeding it into a cogeneration plant that in turn generates totally renewable electrical and thermal energy.

Biogas production from waste biomass

Today the production of energy from industrial and agricultural wastes is not a new process in Europe. However, its application continues to represent a major challenge due to the many barriers that hinder their use (insufficient knowledge of collection and reuse practices, inadequate pre-treatment technologies, absence and/or lack of cooperation between operators in the supply chain, etc. …).

One of the most promising wastes as a resource for the gas production from renewable sources are the grass clippings resulting from land management. The potential energy of grass from the maintenance of urban, agricultural and protected areas is big, but remains largely underutilized in Europe. In fact, there are thousands of kilometers of grass strips along roads and waterways that are regularly mowed; tons of fresh grass cut, chopped and left on site.

Grass clippings: useful biomass for biogas and biomethane plants

For example, Veneto Agricultura has estimated that in the Veneto Region, the collection resulting from mowings exceeds 500 tons of dry matter per year. A quantity sufficient to make it convenient for use in the production of biogas and biomethane.

“Fresh grass can be used in biogas plant even if it has a lower energy potential than corn silage. It wil be sufficient organize the plants with appropriate storage facilities and pre-treatement systems. So, it’s possible to make land maintenance a cheap operation, which must be done in any case. “

Antonio Tomezzoli

President of Veneto Agricoltura Consortium

Veneto Agricoltura, together with 12 other partners (University of Verona, five Belgians, two Germans, one Portuguese, one Danish) participated in the GR3-Grass to Green Gas Resource demonstration project, funded by the Intelligent Energy Europe applied research program. With this, studies have been promoted which have shown, according to conservative estimates, the potential savings of 7.800 tons of oil per year, and consequently the reduction of 39.000 tons of Co2 equivalent

You can read here the complete paper with the results published by Intelligent Energy Europe

How does BioBANG® improve the production of biogas from grass clippings?

BioBANG allows to overcome these barriers that hinder the use of grass mowing for biogas. The disintegration guaranteed by controlled cavitation increases the disintegration of the fiber, reduces the viscosity and retention times of the grass allowing its energy enhancement.

The innovative BioBANG’s cavitation pre-treatment allows to enhance the use of wastes, i.e. grass clippings, guaranteeing the biogas and biomethane plants to save money from the daily feeding, optimize the plant’s hydraulic management and increase their yield.

Therefore, thanks to BioBANG® is possible to transform byproducts derived from land management, usually considered as waste, into low-cost raw materials to produce clean energy, allowing AD plants to increase their eco-sustainability and thus fall within a context of circular economy.

Biogas from grass clippings - Dynamic viscosity
Pic 1. Dynamic viscosity: Left, raw grass clippings; Right, grass clippings after BioBANG®’s cavitation

Biogas from grass clippings - Separation degree
Pic 2. Separation degree: Left, raw grass and slurry; Right, grass and slurry after BioBANG®’s cavitation

Biogas from grass clippings
Pic 3. Visual effect: Left, raw grass clippings; Right, grass clippings after BioBANG®’s cavitation.

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