Cardiff-based biotech company Genesis Biosciences has developed what it describes as a novel and low site footprint solution to help bolster the performance and environmental credentials of anaerobic digestion (AD) systems.
The firm’s Additive was developed at its South Wales laboratories by experts in the fields of microbiology and chemical engineering, and is the latest product in its range of microbial solutions. Researchers were able to identify a novel mineral carrier with the correct parameters to bolster the most sensitive microbial components of the AD system and, through extensive laboratory and genomic screening, it was found that if paired with non-pathogenic and naturally occurring Bacillus microorganisms, it was capable of anaerobic growth as well as enhanced sludge and organic polymer degradation.
Together, the two components are said to offer an operator a simple-to-apply biotech solution that can operate over a wide range of pH values and temperatures and in a range of reactor configurations. The expansive metabolic capabilities of the bacillus microorganisms and the universal tolerance of the mineral additive allows application across most organic feed types spanning many different industries including sludge fed systems, agricultural waste fed systems, slurry fed systems, food and municipal fed systems, landfill leachate systems and one and two phase configurations.
Dr. Chris Charles, Senior Research Scientist and WWT Specialist at Genesis Biosciences, explained: “With a growing demand on companies and authorities to better their environmental credentials, decrease their waste and lower their CO2 emissions, AD and practices such as sludge to land are now being touted as circular economy champions.
“The ability to take human and other waste streams such as agricultural and food, and turn it into both energy and a fertiliser is attractive from a commercial aspect and a palatable ‘green’ concept that the general public can both understand and appreciate.
“The Evogen WWT Biogas Additive is an innovative product based on a synergistic, dual phase technology that works to accelerate the biogas conversion rate, decrease the volume of undigested sludge and increase the yield of biogas production. Through this synergy, Evogen Biogas Additive helps to increase the amount of methane produced, decrease the final sludge volume, bolster stability of the system and enhance overall productivity.”
Anaerobic digestion (AD) is fast becoming an integral part of the wastewater treatment process amongst local authorities and private companies. The ability to use microorganisms to produce methane rich biogas from sewage sludge and organic waste matter offers the potential to produce heat and electricity from an ever present and growing waste source. Through the AD process, specialised microbes interact in the absence of oxygen to breakdown the organic components of sludge and waste to facilitate biogas production. The AD system therefore greatly decreases the final volume of the original sludge or waste to be disposed of whilst yielding energy that can be used to offset plant processing and operating costs. Furthermore, the final waste or digestate produced from the AD process is capable of being used as a bio-fertiliser in what is termed ‘sludge to land’ strategies.
Although high in potential to create a beneficial circular economy, there are still some key challenges and drawbacks with the AD system including time, waste, yield and costs; Time-wise, the process can be slowed down by inhibitory environmental conditions that impact the resident microbial consortia and lead to a decrease in metabolic activity. Low microbial activity, less than ideal growth conditions or an inefficient AD system can also cause losses in methane yields and therefore lead to high volumes of residual sludge which must be processed and disposed of via practices such as landfill or incineration. All these downsides increase the running costs and ultimately impact the cost-effectiveness of AD systems.
The Evogen WWT Biogas Additive helps to optimise the anaerobic digestion process in order to overcome these typical challenges. Working in tandem, a mineral-based powder carrier and Bacillus microbes assist in the breakdown of organic feedstocks to optimise biogas production. The mineral-based powder carrier acts as an ion exchanger that boosts interspecies electron transfer and serves as a colonisation site for methanogens, while the Bacillus microbes enhance the hydrolysis and fermentation phases of the digestion process by secreting anaerobically active hydrolytic enzymes.
Dr. Charles continued: “Following the addition of the Evogen Biogas Additive, the biogas conversion rate is accelerated, the volume of undigested sludge is reduced, and the biogas yield is significantly increased, resulting in lower running costs and a greater financial return. By partnering interacting Bacillus microorganisms with diverse extracellular enzyme profiles, we can ensure that our additive performs across a broad spectrum of organic substrates from sewerage sludge to agricultural and food wastes.
“In combination, both the mineral carrier and the Bacillus microorganisms form a stable product – more so than other sensitive types of microorganisms that could be used as a potential additive – and boast a long shelf life of up to and over two years.”
For more information about Genesis Biosciences and the range of waste water treatment solutions they offer, visit http://genesisbiosciences.co.uk/wastewater.
