Modern Toilet Generates Energy

Environmental Engineering [Prof Jaeweon Cho] at South Korea’s Ulsan National Institute of Science and Technology specializes in water and waste management. He has developed an energy-generating toilet called BeeVi (pronounced beevee) that recycles your waste in three ways. Liquid waste is processed in a microbial reaction tank to make a liquid fertilizer. Solid waste is pumped into an anaerobic digestion tank, which results in methane gas used to power a silicone oxide fuel cell to make electricity. The remaining solids are composted to make fertilizer. The daily waste from one person is about 500 g, which can generate about 50 L of methane.

The BeeVi toilets, located on the UNIST campus, pay students in a digital currently called Ggools, or Honey Money in English. Each deposit earns 10 Ggools, which can be used to purchase coffee, instant noodles, and other items (one Ggool is equivalent to about $3.00 value). The output from this pilot project is used to partially power the building on campus, and to fertilize gardens on the grounds. If you want to learn more, here is a video lecture by [Prof Cho] (in English).

Waste management is an area of research around the world. The Gates Foundation has been funding research into this field for ten years, and has held a number of expos over the years highlighting innovative solutions, most recently being the 2018 Reinvent the Toilet Expo in Beijing. We wrote a piece about the future of toilets last year as well.

44 thoughts on “Modern Toilet Generates Energy

  1. Sadly, this is old news. Los Angeles County has been using sewer solids to create methane, and burning it in turbines to offset the sewer plant operating costs. If ever toilet in LA used this tech, the county would sue the pants off the public.
    Even the landfill gas is used to create power. I worked on these systems starting around 1984. All ladfills, and the main sewer plant all are up and running still.

    1. I’ll add this.
      The methane needed to be “Captured” and dealt with, so the landfills are placed under a vacuum, and the gas used to power the generators.
      The sewage plant captures the gas from the digesters, burns it to create energy.
      The remaining dried soilds are sold to Kellogg and the sell it to gardeners. One bag a a time.

          1. Many are obsessed with decentralization that costs more and works less efficiently, for some notion of “independence” – without realizing that they’re still chained to a global supply chain for all the parts and technology.

        1. While you are definitely correct that large scale operations have benefits (in many cases its the only way that makes sense) they also cost heaps upon heaps more to initially build – can’t get the raw materials to the treatment plant without vast infrastructure projects – just because the actually functional part works out cheaper at scale than the million little ones it could replace doesn’t mean the supporting infrastructure does, are often harder to maintain – its all buried under the roads so finding the leaks and doing anything about it is hard, can’t easily be retrofitted into existing spaces and structures, and obviously are not portable.

          These smaller scale operations do have a use, are more flexible to upgrade to work with newer technologies and can scale to suit just about any demand much easier than the giant central operation.

  2. Being paid $30 to take a dump!
    Where do I sign up?

    Seriously, in my woodshop I keep a small jug to collect urine.
    The aerobic bacteria that breaks down the cellulose in my compost heap, uses the urea supplied by the urine.

    1. We skipped the whole technology part and built a vegetable garden right on top of the septic field. Worked great for years – great crops. Until one year someone had the bright idea to run a disc harrow over it. We ended up relocating the whole field.

      1. I had the largest tree on m y block.. It grew so big, it cracked the sidewalk.
        As it turns out, my sewer pipe was leaking into the ground and causing the rapid growth.
        The city ripped it out, and I fixed the pipe.
        My tree today refuses to grow.

      2. Years ago, Google Maps (satellite) of our house showed that the previous owners had extended the garden over the septic field, but there was no sign of that when we bought the house (just a much smaller garden off to the side.)

        Later, when we replaced the deck (close to the septic field), the crew pulled out the foundation beams to replace them with larger ones.
        All of the old beams were black and smelled like sewage.

    2. The numbers certainly dont make much sense unless the study is operating at a big loss.. if instead we figure that the equivalent is 10 coin for 30krw then the value does add up as that works out to be about $.03 usd or the cost of electricity needed to drive an electric car 3/4 of a mile which is also the output of a persons daily contributions cited in other articles. Of course this wouldn’t be the first time a university or government agency paid a grossly inflated price for crap.

    3. “Being paid $30 to take a dump!
      Where do I sign up?”

      Well it is at a University, Gender Studies majors are expecting to get paid for doing s*it when they graduate so why shouldn’t they get paid while they’re there.

  3. If you look at the energy balance of food production (and even ignoring metabolic biochemistry), you’d recognize that this is energy recovery from a massively inefficient system, rather than energy generation.

    1. Considering that `energy generation` as you understand it doesnt exist anywhere, at all, im pretty sure most pf the audience understood the way ot was meant by the author. Nobody thought they had rewritten the laws of physics

      1. If it didn’t exist, we wouldn’t exist. If you could not gain more energy than you invest, then any chemical complexity let alone biological life would not be possible. Plants would use more energy to grow leaves than what the leaves could collect from the sun etc.

        All our primary energy sources are necessarily net positive – gaining more than we invest. Food is not. It used to be, but in modernity food production has turned from an energy source into an energy sink, and waste processing can only reduce the losses slightly.

    2. A large part of that inefficiency is to serve the requirements of the human in the loop.

      Simple solution: Remove the human from the loop.

      If the real goal is to provide power, then make a better, more efficient solution to do that: no human required.

      If the goal is to feed humans efficiently without too much energy escaping the ‘exhaust’, then make food systems that satisfy that need.

      If revising the food systems can fix the problem, then fix the inefficient machine in the loop to reduce the amount of effluent produced.

      If that can’t be done, then maybe it’s time to think about reducing the number of inefficient things in the loop…

  4. Toilet has #1 in front and #2 at the rear bowel. That’s too close to aim for standing up. All men must sit down.

    Have them downtown to pay for parking, give credits to street people.

  5. A receipt for using the loo? Reminds me of this passage from HHGTTG:
    “For years, the fabulously beautiful planet of Bethselamin increased its booming tourist industry without any worries at all. Alas, as is often the case, this was an act of utter stupidity, as it led to a colossal cumulative erosion problem. Of course, what else could one expect with ten billion tourists per annum? Thus today the net balance between the amount you eat and the amount you excrete while on the planet is surgically removed from your body weight when you leave; so every time you go to the lavatory there, it is vitally important to get a receipt.”

  6. “[…] used to power a silicone oxide fuel cell […]” – a SOFC is a Solid Oxide Fuel Cell. The ceramic electrolyte is usually yttria-stabilized zirconium dioxide (YSZ). There are other ceramics being used, but I don’t know of any silicone based ones.

  7. I’ll share a classic story regarding poop.
    Back in time, the Los Angeles County was tempted to install a process that “Claimed” to convert dried poop into fuel, and burn it directly to produce power. (CIRCA 1980s)
    The concept was developed in a lab, under controlled conditions, and seemed to work.
    So LA County AND Los Angeles Department of Water and Power constructed large plants based upon this process.
    The process was named “The Carver Greenfield Process”
    Well, as it turned out, both sewage plants used federal grants for a large portion of the building effort.
    Sadly, the process did nor scale well.
    The dried poop turned out to be a bomb awaiting oxygen to explode.
    LADWP had the first explosion, damaging the facility and injuring some workers.
    LA County stopped the startup due to the damage at LADWP.
    Fast forward to a couple years ago, someone convinced Bill Gates to invest millions into a project to provide power and water to African villages using the same process that failed in Los Angeles.
    I read on Bills blog about this debacle in waiting and had to respond with a “Just Say No”.
    I’m sure the African villages would not be able to make this work and actually save lives.

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