Methane molecules are the critical components of biogas. Image via Wikimedia.
Biogas production is already a side-effect of industrial wastewater treatment. With the right equipment and the right approach, this biogas can be refined and captured before being used as an alternative energy source. But what is the potential of this released energy?
Read on to discover more as we explore how wastewater treatment can be a source of energy rather than simply a necessary part of running a facility.
Biogas From Wastewater
Biogas itself is gaseous material released when organic matter breaks down. This gas contains high amounts of energy and can be combusted to unleash this potential energy as heat. Characteristics like these make biogas potentially very useful as an alternative energy source.
Methane is one of the key components of biogas, making up between 40% and 60% of its chemical content. The remaining percentage comprises carbon dioxide, with some water vapor and other gases. CO2 and other gases reduce the efficacy of raw biogas as a fuel, but this can be removed during treatment to leave behind biomethane, ready for use as an energy source.
The biomass used to produce biogas is often associated with agricultural byproducts or waste produced by human communities. However, it can also be derived during industrial wastewater treatment. Following treatment, wastewater effluent can be used as a fuel source for biogas production, unlocking much of the energy contained while also removing issues associated with disposal.
The University of Florida identified wastewater from ethanol production facilities, distilleries, slaughterhouses, petrochemical plants, and biodiesel facilities as a key source of high-strength biomass. In contrast, food, dairy, citrus, and juice processing plants, as well as canneries and breweries, are medium strength sources.
Advantages of Biogas as an Alternative Energy Source
What are the advantages of biogas production from industrial wastewater treatment? Take a look at some of the key benefits.
A Renewable Energy Source
While biogas is not a wholly “clean” energy source like wind or wave power, it is considered renewable. The reason biogas does not meet all of the credentials for a clean energy source is found in the treatment phase — gas released from biomass still needs to be cleaned and refined before it can become a viable energy store. Heat may be required to break the organic matter down.
Despite this, organic matter can be regrown and reused, which makes biomass sustainable. Unlike with the renewal of coal, oil, and gas supplies, there is no need to wait millions of years and subject materials to intense heat and pressure — any organic matter can be used to create a sustainable source of biomass. The renewal process is relatively quick and efficient and occurs naturally in most cases.
A High Amount of Potential
There is a huge amount of potential to harvest and harness biogas worldwide, and much of this potential is untapped. In 2020, 67 billion cubic meters of wastewater were produced across North America and Europe. In the United States, this translated to 231 cubic meters per capita. This is a huge amount of wastewater, all of which will need to be properly handled, treated, and disposed of. While not all of the waste will be suitable for biogas production, a high proportion of it will be. With the right approach, a wastewater biogas project could release vast amounts of potential energy.
Of course, there is more to biogas than wastewater treatment. Increasingly, biogas is being harvested directly from agricultural sources, something that is likely to have a profound effect on rural communities that may be struggling to meet energy requirements. Biogas digesters and other pieces of infrastructure could be the keys that unlock global energy solutions in the near future.
Reductions in Pollution
Biomass is highly valuable in energy, but it is a nuisance when it comes to wastewater treatment and handling. This mass must be broken down, removed from the water, and disposed of correctly. If allowed to progress through the wastewater system and enter the local water table, the results can be catastrophic. While there are measures and regulations in place preventing this from happening in the United States, the risk remains. What’s more, it is expensive and difficult for organizations to stay compliant, and facility managers also need to worry about wastewater odor control.
Siphoning off this biomass and feeding it into a digester or other piece of equipment is a handy way to sidestep these disposal concerns. Rather than being a nuisance — and potentially dangerous — biomass becomes a viable energy source, ready for release. This energy can be used internally, within the facility itself, or it can be provided to municipal authorities who may be willing to pay a tariff for it.
Aligns With Existing Processes
One of the key advantages of biogas energy is the fact that its raw materials come from processes that are already happening. Facilities are already producing wastewater and will continue to do so whether they like it or not. This means they must continue treating this wastewater and dealing with the resulting byproduct.
It doesn’t take massive modifications or a significant conceptual shift to start harnessing biogas. Facility managers are currently still disposing of wastewater byproducts — they can simply feed this byproduct into a digester or refinement process instead. This alignment with existing processes makes it easy for facilities to adopt a more sustainable approach to industrial wastewater treatment and biogas production.
Huge Potential, but Some Downsides
It’s worth bearing in mind that biogas is not a perfect energy source. In colder parts of the country and parts of the world, organic matter will not break down effectively and will need additional energy to help it along. This reduces the efficiency of the process. In heavily populated areas, carrying out a biogas production program may not be feasible, and other alternatives may be required.
But biogas does not need to be perfect. Shifts towards renewable energy do not involve replacing one totemic energy source with another. Instead, various renewable options — working together in unison — are required. Biogas production fits neatly into this more diverse approach and may be a desirable option for facility managers looking for a better way to handle wastewater sludge.