As the threat of climate change looms closer, the need for alternative energy sources becomes more evident. The solution to both the world’s power and environmental needs may lie in unexpected places. What if a potential answer for the ongoing electrical and ecological crises was wastewater treatment energy?
Today’s industrial infrastructure creates a lot of refuse, but it may also offer a solution to its own problem. Wastewater treatment plants are both places of excessive waste and potential energy sources. With some modifications, these facilities could become a sustainable and reliable source of electricity.
The world is in the middle of a global energy crisis. Humanity is using more power than it ever has before, and is drawing most of it from unsustainable sources. As energy needs grow and the environment deteriorates, the need for a robust solution increases.
Global energy consumption could rise by 50% by 2050, according to the U.S. Energy Information Administration (EIA). That’s an astonishing figure, given that the world already uses more than 600 billion gigajoules of electricity a year. We’ll need a considerable amount of energy to sustain society in the future at that rate.
As people use more power, it creates another, even more pressing issue. The vast majority of the world’s energy comes from fossil fuels like oil and coal, which harm the environment. If power consumption continues on its current course without switching to renewables, it will have disastrous results.
New energy solutions need to solve these two problems at once. They must produce more power while remaining environmentally sustainable. Wastewater treatment energy is one example of a solution that answers both issues.
Wastewater treatment plants are in particular need of improvement as far as energy efficiency goes. They serve a crucial purpose, so doing away with them altogether isn’t a viable option to save electricity. At the same time, much of the power they consume ends up wasted.
These facilities often treat massive quantities of water every day, which requires a similarly vast amount of energy. In total, U.S. wastewater plants use 100 billion kWh each year, which accounts for 3% of the nation’s entire power consumption. These tremendous numbers equate to billions of dollars in energy costs and a hefty dose of fossil fuels.
With modern tools and techniques, wastewater treatment facilities don’t need to be using that much power. The process has the potential to generate electricity, yet many facilities don’t take full advantage of this. When these plants don’t harness this potential, they waste it, which is an issue given the energy crisis.
Wastewater treatment generally involves four steps: primary treatment, secondary treatment, anaerobic digestion and disinfection. Each step can improve energy efficiency with different equipment, but energy-gathering happens in the third stage. To understand how, you need to know what happens in this part of the process.
The first two steps remove solid and dissolved waste from the water. In the anaerobic digestion phase, facilities use bacteria to break down the separated organic solids from the first two stages. This process produces methane, which these plants could capture and use as a biofuel.
If released into the atmosphere, methane contributes to ozone depletion, but it can also serve as biogas. Companies can either burn this methane in specialized engines or purify it into more versatile natural gas. This second option is especially promising, given the current state of natural gas.
Fracking is the most common method of extracting natural gas in the U.S. This process is infamously destructive to the environment, as it uses tremendous amounts of water and can contaminate the surrounding ecosystem. Gathering natural gas from the methane produced in wastewater treatment provides a safer alternative.
Wastewater treatment energy presents substantial potential, especially given how underutilized it is. According to the American Biogas Council, 1,269 wastewater facilities use an anaerobic digester, but only around 860 use the resulting biogas. That means there are hundreds of facilities that wasting considerable amounts of energy in the U.S. alone.
Not using this methane doesn’t just mean missing out on a potential source of energy. If facilities release methane into the environment, it could cause further harm to the ozone layer. Methane has the potential to be a renewable energy source, but if companies don’t use it as such, it’s actively harmful.
The world’s growing population also has a part to play in all this. Some estimates predict the world could host close to 10 billion people by 2050, and that means more wastewater. This, in turn, means more energy that treatment facilities can produce.
Wastewater treatment energy holds potential for treatment plants, the environment and city management. These benefits don’t end at environmentalism, either.
Generating energy from wastewater treatment presents an economic incentive for the facilities that do it. Electricity isn’t cheap, and plants use a lot of it. If they were to take advantage of the biogas released from their process, they could drastically reduce their energy spending.
Harnessing the power of this methane is preferable to gathering energy from external renewable sources. Facilities are already creating biogas as a byproduct, so they wouldn’t need to pay for fuel. The only expenses involved are those for the machines to gather and use methane.
Combining biogas harnessing with other methods to improve efficiency can create not just energy-neutral, but energy-positive facilities. The Marselisborg wastewater treatment plant in Aarhus, Denmark, saw an energy-efficiency rate of 153%. Facilities can sell this leftover power to the city for even further economic gain.
The environmental benefits of wastewater treatment energy are obvious. If treatment facilities could become energy-neutral, then it would substantially lessen the world’s overall power consumption. If they would grow to be energy-positive like the Marselisborg facility, they could offer sustainable power to other processes.
Wastewater treatment energy also provides a solution for what to do with potentially harmful methane. Methane is the second-most prevalent greenhouse gas, making up 16% of all greenhouse gas emissions worldwide. Using this biogas for power instead of releasing it into the environment helps protect the ozone.
If wastewater treatment plants became a more widespread source of natural gas, it would further help the environment. It would decrease the world’s reliance on fracking to generate natural gas, lowering emissions and saving water.
Wastewater treatment itself is crucial to the survival of the environment. As global eco-friendly initiatives grow, it will likely mean more wastewater treatment, to reduce pollution and increase clean drinking water. With more facilities or higher throughput, the energy generation these plants provide would grow as well.
Wastewater treatment energy also benefits city management. If these facilities became energy-positive, then they could sell that power back to the grid. This provides the cities they inhabit with more sustainably sourced electricity to give to its citizens.
These treatment plants could serve a dual purpose, both cleaning water and generating electricity. This conversion would give cities new sustainable power plants without requiring the construction of additional infrastructure. Since plants produce methane already, they would be more affordable power sources than fossil fuels.
Hybrid wastewater treatment and energy plants could be enticing for areas lacking proper waste management. Some cities in developing nations may be hesitant to build larger, more advanced facilities because of the cost. If these plants also produced power for the area, however, they would be a more attractive investment.
By combining power generation with water treatment, cities solve two problems at once. They may not want to spend money on two separate facilities, but one doing the job of two is another story.
Looking to wastewater treatment plants as an energy source isn’t just a theory, either. It’s already happening around the world, as evidenced in Denmark’s Marselisborg facility. More plants are using their biogas byproducts to power their operations and the area around them.
As far back as 2012, wastewater treatment facilities have pushed to become energy-positive. The East Bay Municipal Utility District in California became a net energy producer almost 10 years ago. All five wastewater treatment plants in Vancouver, Canada, generate electricity from their processes and are looking to expand.
As more facilities start engaging in this practice, they’ll inspire others. The growing public concern over climate issues and the increasing need for energy will also help drive this change. Wastewater could likely be a common power source in just a few years.
Governments and private companies can’t ignore climate issues or energy needs anymore. As both concerns continue to grow, the world needs solutions to answer both at once. Wastewater treatment energy is one such solution.
The future of wastewater treatment is likely also one of green energy production. Further development in this area will decrease fossil fuel reliance, reduce greenhouse gas emissions and even improve economies. The prospect is too beneficial to ignore.
Emily Folk is a conservation and sustainability writer and the editor of Conservation Folks.
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