Working in partnership with Nijhuis Industries, Alps Ecoscience can report on the positive effect of Bio-Organic Catalyst (BOC) on Anaerobic Digester (AD) performance. Last year, Alps Ecoscience was given the opportunity to start a Bio-Organic catalyst (BOC) trial at an Anaerobic Digestion (AD) plant in Cornwall. This AD plant has two mesophilic anaerobic digesters, followed by a pasteuriser and a thermophilic digester. It receives a variety of feedstock, from liquid feedstock such as DAF sludge, pig slurry and glycerine, to solid feedstock such as maize, whole crop rye, wheat grain and vegetable trimmings.

Maize whole crop, rye and wheat grain contain high amount of lignin and cellulose and are harder to be broken down completely in the anaerobic digesters. BOC acts as a surfactant and it increases the surface area within the feedstock to allow better access for enzymes and microbes, which is beneficial for the AD process.

During the trial, which started in October 2020, a bio-organic catalyst, ECO CAT, was dosed at 10L/d into the feedstock. After 3 months, we can see that the FOS/TAC of both digesters are low and stable, both remain around 0.27, compared to an average of 0.38 before the trial (28% reduction).

Biogas produced from the digesters contains higher percentage of methane (2% increase in digester 1 and 13% increase in digester 2) and lower level of hydrogen sulphide (11% reduction in digester 1 and 44% reduction in digester 2). We also observed an 8% increase in total methane production, and a 6% increase in VS yield and the site is feeding 10% more feedstock compared to before the trial.

Overall, we are observing very positive results from the addition of Bio-Organic Catalyst into AD process. By adding BOC, the digesters have a healthier FOS/TAC, VS yield has increased, and they produce a higher quality of biogas.

Alps Ecoscience is a UK and European Distributer for Bio-Organic Catalyst Inc. who produce a line of proprietary product compositions (Patent 730371). In addition to supplying additives, Alps Ecoscience provide a range of Anaerobic Digestion (AD) specific managed services, including a cost per tonne pricing model for biogas plant optimisation. For more information, please contact us or email: alan@alpsecoscience.co.uk

Thank you to Yexin Feng of Nijhuis Industries and Wade McRoberts of Alps Ecoscience, co-authors of the original trial report, for your contributions to this extract.

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