Extracting energy from wastewater

Each day, breweries and wineries produce thousands of gallons of wastewater, which is either poured down the drain or shipped to treatment facilities at a high cost to the companies.

Now MIT spinout Cambrian Innovation is commercializing a novel treatment system, called “EcoVolt,” that uses electrically charged microbes to treat and create power from wastewater. The company — which aims to leverage biotechnology as a way to solve environmental issues — is also modifying their system to generate value from wastewater in agricultural and military fields, and to convert carbon dioxide to fuels for applications on Earth and in space.

Today’s industrial infrastructure manages basic resources linearly, raising the cost of waste disposal and causing environmental harm. But a more cyclical approach — where waste is used as an energy source — could provide higher profit yields and “eliminate the tension between the environment and economics,” says CEO Matt Silver SM ’05, PhD ’10, who co-founded Cambrian with Justin Buck PhD ’12, now the company’s chief technology officer.

“The treatment of wastewater, for example, consumes over 3 percent of the electricity in the United States, yet organics in the wastewater have energy that can be extracted and used locally,” Silver says. “And that’s the case for a lot of waste products in general.”

Cambrian’s automated and modular EcoVolt system — delivered on a flatbed and installed in a day — consists of a headworks unit, which houses computers for automation and control, and expandable 20,000-gallon treatment units. In these units, microbes called “exoelectrogens” execute a unique process, electromethanogenesis — which is being used for the first time ever in treating wastewater.

Exoelectrogens, coated on anodes, consume the wastewater’s remaining organic pollutants and, in the process, generate electricity. This electricity travels through a circuit and onto cathodes coated with separate microbes that consume that electricity — along with carbon dioxide — to produce biogas at a rate of up to 100 cubic feet per minute. This process enhances naturally occurring anaerobic digestion in wastewater, Silver says, as it stabilizes treatment, improves biogas quality, and enables a higher degree of automation.

The biogas enters a connected cogeneration system for power conversion. Depending on several site factors, this produces anywhere from 30 to 400 kilowatts per hour of electricity. Treated wastewater exits the reactor with 80 to 90 percent of pollutants removed, so it can be used for irrigation, equipment washing, and other things.

The system can treat 10,000 to 1 million gallons of wastewater daily. At that rate, a winery would shave about 2 pounds of CO2 per case off of its carbon footprint, through carbon-free energy generation and avoiding municipal wastewater treatment — “effectively planting over 4,400 acres of trees in a year,” Silver says.

Since January, the Bear Republic and Lagunitas breweries, both in drought-stricken California, have purchased EcoVolt systems. At current usage rates, Cambrian estimates the system will generate enough electricity to meet 25 to 50 percent of these breweries’ needs and allow reuse of about 25 percent of their water. It could also eliminate 10 trucks of wastewater shipping per day for Lagunitas.

All in the design

Increasingly, the beverage industry has employed anaerobic and aerobic wastewater treatment processes, but these are expensive and difficult to adopt, Silver says.

Aerobic processes — dissolving air into wastewater, where aerobic microorganisms degrade pollutants — consume a lot of energy and generate biosolids (organic materials) that are managed at cost. Processes where anaerobic microbes eat pollutants, while producing small amounts of burnable methane, have gained popularity in the last few decades — but such systems only function under specific circumstances, are prone to failure, and are difficult to operate.

EcoVolt, on the other hand, is applicable to a range of sites, and has demonstrated a more robust treatment process, meaning better power generation and higher yields for customers — and is therefore more economical, Buck says. But the system is also modular, meaning customers can incrementally add components, such as larger treatment units or conversion generators.

It’s an architecture influenced by Silver’s graduate years in MIT’s Engineering Systems Division, which stresses reliability, scalability, and flexibility in designing large-scale, complex systems. “EcoVolt gives them more flexibility with how they implement treatment systems,” he says. “The whole idea is to minimize nonrecurring engineering and operating costs, while providing customers with the option to expand at low cost via a modular architecture.”

Moreover, though, EcoVolt is automated, remotely monitored, and provides real-time data — thanks to using exoelectrogens as sensors. “These bugs are generating electricity, and that’s something we can sense and read out, in real-time, to see how well the reactor is doing,” explains Buck, who invented Cambrian’s sensor technologies.

With EcoVolt, Silver says, Cambrian aims to make treating and reusing water easier and more affordable, as America’s dependence on water increases, along with water pollution.

“Almost every product we make has a water footprint,” Silver says. “As our economy grows, water tables are dropping and wastewater pollution is rising, causing many companies to consider water risk in their overall strategy. The need for more cost-effective solutions is increasingly acute in the developed world, and also critical in the developing [world]. We are leveraging biotechnology to provide the highest return on investment for managing water.”

To that end, Cambrian is working on other projects that leverage exoelectrogenic microbes to treat wastewater. One project, called BioVolt, is a self-powered water treatment system for U.S. Army forward operating bases that treats wastewater and generates electricity to power itself. Another project, funded by the National Science Foundation, uses exoelectrogens to sense nitrate in wastewater, cheaply and with very high specificity, for the agricultural industry.

“Earth as a spaceship”

EcoVolt is valuable today as a solution to Earth’s water issues. But the core technology began as a bit of aerospace ingenuity — and has since found its way back to space.

Meeting at MIT in 2006 over a shared fondness for biotech, Silver, then a research scientist in MIT’s Space Systems Lab, and Buck, a biological engineering graduate student, won a grant from the NASA Institute for Advanced Concepts program to create a life-support system that could treat waste and generate electricity for astronauts. Soon, they came across exoelectrogens; a 1999 study had revealed that exoelectrogens could, in fact, generate more amps per square centimeter than was previously thought.

This made exoelectrogens a third — and largely better — candidate for wastewater treatment, over aerobic or anaerobic methods. Launching Cambrian with a Department of Agriculture grant to focus on agricultural wastewater, the team soon moved to its current Boston headquarters. By the time they entered the 2010 Cleantech Open competition — and won — they had shifted focus to the food and beverage industry.

Cambrian successfully piloted its first system in 2010 and then, over 14 months, from 2011 to 2012, demonstrated its system at industrial scale at the Clos du Bois winery in California.

In 2012, NASA began funding a Cambrian project, called ExoGen, that uses electromethanogenesis to more efficiently extract oxygen or fuel from CO2 for long-duration space flights. NASA currently carries out oxygen recovery from CO2 in a multistep chemical process; ExoGen will make it a simplified, one-step process.

Surprisingly, shifting from aerospace to Earth applications, and back again, has been an easy transition, Silver says. “The challenge of supporting astronauts in space is very similar to sustainability on Earth,” he says. “What you’re looking to do in space is maximize reuse, while minimizing energetics. If we look at Earth as the spaceship, it’s the same problem.”

With EcoVolt, and its other ongoing projects, Cambrian’s overall aim, Silver says, is to leverage biotechnology to advance a sustainable “industrial ecology,” where the waste of industry is recycled to create energy and value — much like in natural ecosystems. “In a natural ecosystem, there really is no such thing as waste,” Silver says. “It’s just another resource.”

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26 thoughts on “Extracting energy from wastewater”

  1. This is a brilliant idea that benefits the environment immensely as it is an answer to a number of different environmental issues. The fact that this treatment system not only produces purified water that can be reused but also creates energy in the process is truly extraordinary. Both water and electricity are resources we have to use and maintain wisely, and a world without them is something we do not want to end up in. Another benefit of this process is that it would reduce a winery’s carbon footprint by about 2 pounds of CO2 per case. This system is not only a great benefit to the environment, but also to the industries using them as they reduce the amount of money spent on water and electricity consumption as well as creates job opportunities.
    Ultimately I feel this process is a great advance for sustainable development and it is amazing to know that people are taking an interest into implementing the sustainable development of our planet.

  2. The EcoVolt is a magnificent innovation. So many countries struggle with water purification and electricity generation. This helps in waste management as waste water is purified and at the same time electricity generated. It would be greatly appreciated if they were to make the system highly efficient and cheap to operate such that poor countries can utilise the facility to their advantage. This will also reduce cost and effects of disposing water unsafely.

  3. This really does hit two birds with one stone. To purify water and at the same time generate electricity, which are both dwindling commodities (especially in South Africa), is a giant leap forward for environmentalists. An outstanding quality is that it has applications in a large variety of fields. For example it has applications in both economic and socio-environments as it allows for a more cost effective method of waste disposal for businesses, as well as, a sustainable way for communities (particularly those that are rural) to have access to clean water and renewable energy. As a whole I see it as a crutch that is gonna help rehabilitate the earth towards sustainability.

  4. This is a brilliant idea as it has many benefits to our natural environment as well as sustainability.

    Reusing waste water is like another renewable resource because water in the water cycle itself is continuously going through different stages and as humans continue to use water to sustain their needs in life as well as wants, the water table levels drop-as mentioned above.
    Using waste water as a source of power for factories themselves as well as the small surrounding areas will delay the degradation of water in the water table as well as decrease the need to continuously transport the waste water to other parts to be purified.

    From a broader perspective, waste water reuse ultimately reduces carbon footprint most factories produce.

    Exoelectrogens should have been used earlier in the century.
    I believe this is the beginning of more efficient water pollution prevention and more factories worldwide should adopt this solution instead of the costly transportation and chemical purification of waste water.

  5. It is a well-known and lamentable fact that the Earth’s natural resources are limited. Prominently and importantly, water and energy are in high demand. If this invention can truly reduce waste of water and produce electricity in the process, it can solve the problem of how to generate energy while limiting our carbon footprint. This ground-breaking invention can prolong the lifetime of our Earth’s resources and quality of life for humans.

    Not only is this a new method of producing energy but has the added benefit of being a more cost efficient and eco-friendly way of producing energy. The CEO has a valid point in referring to the EcoVolt as a new resource that has been discovered.

    This invention will not only minimize the effect we have on Mother Nature, but will also create many job opportunities in the process. The cost saved by installing an EcoVolt will be amazing since it can generate up to 50% of electricity to power the brewery and make it possible to reuse 25% of the water used on site.

    This is definitely the only way forward. We only have one Earth and if we want to enjoy a quality life on it, we need to look after it.

  6. Yes it quite sustainable as we people continue to waste water or as there has been too much water wasted, each and every day. An as for being economically boosting it is because people will get jobs and it will reduce unemployment. To Zandile

  7. It is absolutely mind-blowing what these systems can achieve. To use this technique to extract energy can have a huge impact in restoring energy and managing water, but imagine combining systems to create a nearly self sustainable system. The technique can probably also be used in household similar to systems like composting toilets (dry toilets) to produce methane and use it as an energy source. These systems are usually used to save water as well as creating compost for use in gardens (even edible gardens such as vegetable gardens), but research has shown that the amount of fertilizer that can be produced by one average family is more than enough to fertilize a garden to sustain more than one family, thus excess compost can be used to make energy as well.

    Rainwater systems can also be combined with these techniques. Even if rainwater is used only for purposes other than for drinking, it can reduce water usage by much more than 50%. If a system can be created where everyone can take part we can overcome most problems we experience today. Systems can reduce water usage, provide energy as well as helping with food scarcity. This stuff is what will keep the world going round!

  8. The development of EcoVolt is undoubtably a pivotal advancement towards a sustainable lifestyle that is becoming more and more important in a world of limited resources, of which water is probably the most important.

    This technological advancement could have huge benefits to many towns and city’s in Southern Africa, if used on a large scale, where water is in very short supply and electricity is a scarce luxury for many. The reclaimed water can be used in the outskirts of the city’s and towns for small scale agricultural pojects as well as for schools and recreational areas which are mostly dustbowls in most of Southern Africa where rainfall is poor and sporadic and infrastructure delapadated or non existent. The reclaimed water would heavily reduce the populations dependence on supply dams. The electricity produced can be fed into the system, reliving pressure of the coal stations that are used widely in this region, in the process conserving another precious natural resource and lowering carbon emissions into the atmosphere.

    Current treatment of waste water in these regions is very inefficient and an extremely energy and resource defendant process where tones of expensive chemicals may be used. The production of such chemicals is not a very eco-friendly process, so reducing the demand of these chemicals will in no doubt be a secondary benefit of the EcoVolt system.

    All in all this is a great step forward in the right direction towards a more sustainable and “green” future.

  9. This type of energy generating system will be beneficial to the environment since it is sustainable. It will not use up any of our fossil fuels but it will use wastewater which is in abundance. Using this wastewater will minimise any chances of pollution, since it was usually disposed improperly by factories. Besides this EcoVolt system being sustainable, it will also enable the opportunity to make huge profits from it because the wastewater is obtained freely and extracting energy from it would generate profit without incurring expensive generating costs. The water obtained after the EcoVolt process can be used for irrigation since it has been decontaminated, and this is economical for the environment. I truly believe that this EcoVolt system of generating energy will be a success to both the environment and the industry.

  10. Yes Zandile, it is economically beneficial because there is huge amount of waste water from brewery industries, irrigation from agriculture and many others.Which means there will be more waste water that will be recycled leading to a high yields of electricity.

  11. EcoVolt systems is by far the best hope of a sustainable future, it is the answer to the questions we have been raising all along. National Geographic states that there is a depletion of freshwater sources and it has has recently reached 20% worldwide, this is clear proof that our planet is running out of resources. EcoVolt could be the answer to minimizing this upcoming threat to life and the road to reviving our ‘soon doomed’ planet. This system will not only save our planet but there are a lot of benefits to it. Water is not only saved but it is purified and reused as well, the breweries will benefit a lot from this projects in terms of saving money on energy supply and they will be a maximum produce. These ‘exoelectrogens’ can greatly improve the economy and the planet as a whole if adopted and applied, EcoVolt surpasses all the systems that have been applied in the past and have cost the economy and the planet so much.
    We could be looking at the next stage of economic evolution, this what we have been waiting for all along and it is a promise to a safer and sustainable future,I raise my hat to Cambrian and the geniuses behind this exceptional invention,Truly one a kind!!

  12. With the current size of the human population and the rate at which it is growing, waste management should be a top priority for government and large waste producing companies worldwide. People continually need products and the waste produced in the production and consumption of these products should be managed effectively and if possible, used as a resource like it was done in the processes mentioned in this article. The ecoVolt system is a good example of how waste can be used to our advantage. This could lead to a healthier environment and decreased natural resource use and wastage. More money needs to be spent developing ideas like the ecoVolt system and more effective and beneficial waste management.

  13. Water is with no doubt an essential resource of life. We strive by all means to make rational use of it and preserving it. This innovation is by far the most. It has surpassed the hindrances that earlier systems have been used. It is truly economical and will therefore benefit our environment in all ways possible. This will surely benefit our generation and those to come on a very large scale.

  14. Indeed it is incredible how technology is growing.Who would have thought waste water could be so useful to such an extent of electricity generation.We all know that electricity and water play a crucial role in our lives.

    This invention will increase the production of water and electricity.This will reduce shortage of electricity since water is renewable than fossil fuels which undergo a long process before being used to generate electricity.Since we know that water which is available for use is low in percentage this invention will help with more production of water and electricity which are the the most resource required for industrialization and agricultural use.This will have a great impact in the production in the industries and in agricultural site therefore there will be an improvement in standard of living.

  15. Even if waste disposal from industries is in huge amount the cycling of waste water will lead to high yield.And what a way to sustain our environment! It also is true that this world is facing water crises but even if is being consumed at huge amount at least Ecovolt does something good about it.

    It is also a good thing that NASA does not support only Astronauts in space but also inventions like Exogen.

    And yes Mogano Ramalau that is true, “benefit from our own waste”.

  16. This invention is really a break through in the sustainability of our Earth. It is a good way to keep our planet to be clean and we benefit from our own waste, it does not get better than that. As the the CEO said now waste is another resource, meaning our economic well being will expand as a new market has been published.

    EcoVolt’s design really will help our Earth be a more cleaner and making it much more easier to sleep well knowing that out there people are watching over our Earth. This invention will change our life’s to the better, but we should know that wasted water is not good to us and lets not waste water and be like we know that they will extract energy from it. Our water is essential and this is a great programme to sustain life on Earth

    Benefiting from our own waste, all thanks to the creator of this extraction. A better Earth now the better the future Earth from now.

  17. It is so pleasing and amazing to have such an initiative that solves many problems and also avoid other impacts in such a way that waste water is being recycled to produce electricity, that way air won’t be polluted by huge amounts of greenhouse gases.Recent technological initiatives are expensive, impact our environment and climate but EcoVolt is sustainable and yet so economical.

    I wish this initiative could be expanded in both developed and developing because in developing countries it will be very cheap and many people could have access and developed countries it will help to reduce their green house gases that are being usually produced.

    We need invention like EcoVolt to save our planet and benefit many people.It so amazing to have a great initiative like this one and thanks to Cambrian.

  18. This invention is truly a step towards a more sustainable future which should be the central philosophy in all industries across the world as climate change becomes more of a reality and fossil fuel reserves are increasingly becoming depleted. It’s true brilliance lies in that it makes something useful out from something that would otherwise be wasted or recycled at great expense. EcoVolt’s comparison to a natural ecosystem is justified as it models one brilliantly- as the CEO said the waste is just another resource.

    EcoVolt’s modular design greatly enhances its value as new customers may try a basic system and move to a more advanced system as they see the benefits of the EcoVolt and become more comfortable with it.

    All-in-all this invention is truly one of the greats! It’s sustainable and economical. I applaud Cambrian Innovation for the exceptional invention!

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