There has been a lot of change here at Ashleigh Environmental over the last few months. We’ve hired some exciting new talent and been getting stuck into a number of significant projects. We are applying our Biowave™ microwave pre-treatment technology to different anaerobic digestion feedstocks to improve their digestibility and enhance renewable biogas production. The team have been hard at work on site getting everything up and running and enjoying the Waterford sunshine.
How our Biowave™ technology works
The Biowave™ process uses electromagnetic microwave radiation to efficiently heat feedstock material. The microwaves are readily absorbed by charged and polar compounds, causing them to vibrate, rotate, and release heat energy.
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Unlike conventional treatment where the heat is transferred from the outside of the material to the centre, microwave radiation is directly absorbed on a molecular level and heat energy is distributed evenly across the material. Therefore, the feedstock is rapidly heated in a much more energy efficient way with no hot and cold spots. This is especially effective for complex, highly energy dense but recalcitrant feedstocks.
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The results are faster reaction times for hydrolysis of high molecular weight compounds, disruption of cell walls – and therefore enhanced cell lysis – uniform heating of material, and a product that is an ideal feedstock for efficient biogas production from anaerobic digestion. This means great amounts of renewable energy in less time.
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S-BREW Project funded by the Enterprise Ireland Disruptive Technology Innovation Fund
We are working with NUI Galway and NVP Energy to use Biowave™ technology to address a major global challenge facing the dairy industry.
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FOGs
Fats, oils and greases (FOGs) form a significant fraction of the wastewater from the processing of dairy products. These compounds are insoluble in water and can accumulate in waste streams to form “fatbergs”. They are very difficult to treat in standard wastewater treatment processes. Long chain fatty acids (LCFAs) are the major component of dairy FOGs and these are particularly harmful for the microorganisms in anaerobic digestion. Consequently, FOGs are removed from the wastewater stream using a process called “dissolved air flotation” (DAF). Compressed air is dissolved into the base of the DAF system which expands as it rises through the water column, floating the less dense FOGs along the way. The FOGs are then skimmed off the surface of the wastewater and the effluent is collected for disposal – usually via land spreading. The remaining aqueous phase of the wastewater can now be treated in an anaerobic digestor.
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The circular economy: turning a waste stream to a revenue stream
Currently, dairy processors pay large fees for the FOG sludge to be taken away by waste disposal specialists. The sludge is not considered to have a high nutrient value for the receiving soil. Yet FOGS are very energy-dense compounds. The FOG effluent removed from dairy wastewater can represent up to 50 {92df6d80683b6e3d0cf271bd95f94634aae9c729a7d3025e179e1d637ce3b817} of the total COD, or renewable energy potential, of the waste stream. Using Biowave™ pre-treatment to break down the LCFAs from dairy waste, we will create a product that is no longer harmful to anaerobic digestion and allow the microorganisms to access this untapped energy. In addition to this, disposal costs and associated CO2 emissions are saved. Overall, Biowave™ will lower carbon emissions, not only by creating renewable energy but also by diverting a valuable resource from waste/byproduct disposal.