The campaign for a circular economy is immensely relevant in relation to current affairs. A heavier onus is placed on companies each day to reduce their emissions and hit net zero, but how can this be done? Simon Emms, Business Development Manager, explains the benefits of biogas and anaerobic digestion as a possible solution.
In all types of manufacturing it is inevitable that we reach a point where waste or a by-product is generated. With better technology and a more ecologically conscious mindset, progress has been made to evaluate waste and how it can be reused or repurposed. This is done to reduce the impact waste has on the environment and to support a circular economy. Environmental, Social and Governance factors (ESG) are having more of an influence on how companies can do more to reduce the footprint of their product. In industries such as food & beverage or the automotive market, this is driven by customers and their desire to ‘do more’ for the environment.
Veolia Water Technologies UK has significant experience in optimisation and performance improvement for utilities across numerous industries including the following:
- Petrochemical
- Pulp & Paper
- Automotive
- Steel Production
- Food & Beverage
- Manufacturing
One of our key wastewater technologies that can be used to support the circular economy is anaerobic digestion from our Biothane brand.
What is Anaerobic Digestion?
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Quite simply, it is the process of using bacteria and microorganisms to ‘digest’ the organic matter (compounds that contain carbon) contained in wastewater, these organic compounds are measured using Chemical Oxygen Demand (Commonly referred to as COD). This amount of COD can then determine the potential for the generation of biogas, which is essentially the gas produced by bacteria as a part of the digestion process.
The process of Anaerobic Digestion is fairly simple, it comprises a tank that is maintained at a certain temperature under anaerobic conditions (so no Air/Oxygen is present) allowing the right ‘bugs’ to be grown so that the biological activity is suitable for treating the wastewater, this bacteria is referred to as ‘granular sludge’. The client's wastewater is then added for the bacteria to digest, this works in a similar process to that of a stomach.
As the bacteria digest the organics in the water, they produce a gas, this is what we refer to as ‘biogas’. The design of our Biothane Anerobic Digestion system allows the gas, water and solids to rise before reaching a settler, it is this settler that then separates the solids, liquid and gas.
The core principle of this separation is to keep the granular sludge (solids) in the system for further digestion while allowing the treated water and biogas to pass through and separate. The clean water then leaves the digester and the biogas is collected usually in a temporary storage tank known as a gas holder.
The gas holder has a relatively small retention time and helps maintain the pressure as the biogas is further treated to remove impurities using a gas scrubber, this will remove compounds such as Hydrogen Sulphide which can cause corrosion as well as odour and then leave a ‘sweeter’ gas that can be used in downstream energy production such as a Combined Heat & Power Plant (CHP) or steam raising boilers.
The benefits of producing on-site gas from wastewater has been known for years but as we move to net zero and reduce our reliability on fossil fuels, on-site, self-generated energy offers a stable operating cost platform and increased resilience against the influences of the energy market.
A key thing to consider for Anaerobic Digestion is that is is not as complicated as you may think and with the right expertise provided by Veolia Water Technologies UK, backed by our anaerobic digestion technology (Biothane) and technical specialists, clients can have confidence that the project will meet its objectives.
To start on the journey to realise your own circular economy, please get in touch, we can take you through what is required to start the discussion and the development of an initial design for your site. The process begins with some basic data including COD, Total Suspended Solids, flow rate and a few other core parameters. If you do not have this data, then we can certainly help you with our analytical services.
Get in touch now!
