[HN Gopher] Bacteria generate electricity from wastewater
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       Bacteria generate electricity from wastewater
        
       Author : geox
       Score  : 92 points
       Date   : 2023-09-14 12:18 UTC (10 hours ago)
        
 (HTM) web link (actu.epfl.ch)
 (TXT) w3m dump (actu.epfl.ch)
        
       | 1letterunixname wrote:
       | Bill Gates will drink the results.
       | 
       | https://en.wikipedia.org/wiki/Omni_Processor
        
       | jokoon wrote:
       | Science magic saving us from climate change
        
         | toolz wrote:
         | I can be a bit of an over-optimistic person, but I've always
         | been of the opinion that mass extinction events are always
         | going to occur without intervention and while humans certainly
         | seem to have contributed towards speeding up the timeline
         | heading towards the next extinction event, we're more
         | importantly the only species with potential to mitigate these
         | extinction events all-together.
         | 
         | Without humans extinction events will occur (at least history
         | suggests this is the case). With humans, they might not. For
         | all of our flaws, I think humans are the most beautiful species
         | to come into existence. We have seemingly boundless potential.
        
           | smileysteve wrote:
           | Depends a lot on the timeline and extinction event.
           | 
           | In the case of human caused global warming, human harvesting
           | of forests and top soil, endocrine interfering plastics, or
           | global thermonuclear extinction where there is a causal link,
           | those specific events would not happen without human
           | industrialization (and exponential reproduction).
           | 
           | The Sun will one day consume the earth, the possibility of an
           | asteroid (that humans can't destroy) is still there, the
           | magma/volcanic cycle of heating and cooling is there.
           | 
           | I'm curious what extinction events you're so sure humans are
           | capable of preventing that haven't been directly caused by
           | humans (whales, eagles, buffalo, cfcs). And I don't think
           | bacteria or viruses we've experienced qualify to have been
           | extinction level events.
        
             | toolz wrote:
             | I'm not sure of anything but our potential. It's only been
             | roughly 150 years since the first internal combustion
             | engine. Today a 50lbs machine mows my lawn by itself by
             | communicating invisibly with hunks of metal in outer space
             | traveling at 17,000mph around earth to determine its
             | position on the face of the planet within roughly a few
             | centimeters. This machine cost me roughly a week of labor.
             | 
             | I think the much more interesting question is what sorts of
             | extinction events do you think we will be incapable of
             | preventing in 1,000 years?
        
         | worik wrote:
         | > Science magic saving us from climate change
         | 
         | I hope you are joking
         | 
         | Something to "save" us is not what we need
         | 
         | We have all we need and if we can adjust are economic and
         | social relationships we do not need saving, we can look after
         | ourselves
         | 
         | A big if.
        
       | eggy wrote:
       | I'll have to finish the read, but my first thoughts were the
       | number of organisms we are bioengineering to do specific things,
       | and how they might crossover with other naturally occurring or
       | bioengineered microbes. I remember the plastic-eating microbes
       | found in colder climates[1]. There are other plastic-eating
       | microbes, but they need hotter temps ~86F. These work in cold
       | climates. Visions of the blob with lightning and plastic-eating
       | powers ;)
       | 
       | [1] https://www.cbsnews.com/news/plastic-eating-microbes-from-
       | on...
        
       | ende wrote:
       | It's about time they did something useful!
        
       | Rygian wrote:
       | From the "supplemental information" [1] part of the actual paper
       | [2], the levels of current are measured in mA and tenths of volts
       | (ie. in the order of mW of power).
       | 
       | What is fully unclear to me is how (or whether) that power can be
       | harvested and put to any electrical use. Or perhaps it is only of
       | chemical interest?
       | 
       | [1]
       | https://www.cell.com/cms/10.1016/j.joule.2023.08.006/attachm...
       | [2]
       | https://www.cell.com/joule/fulltext/S2542-4351(23)00352-5?_r...
        
         | kendalf89 wrote:
         | From the video it looks like they are just using a few mils of
         | liquid volume. My question would be how well does this method
         | scale up? Maybe waste water treatment plants could offset their
         | carbon footprint a significant amount or even become a power
         | plant if this technology gets better.
        
           | londons_explore wrote:
           | Most waste water treatment plants are already 'carbon
           | negative' - since they're getting fossil-fuel-free turds and
           | normally turn it into methane for energy generation.
           | 
           | On official charts, it shows as 'biogas' - although usually
           | in statistics the biogas from waste water treatment processes
           | isn't separated from the biogas generated from municipal
           | landfills.
        
             | KarlKode wrote:
             | I was skeptical about your claim but I turns out that you
             | are right! I knew about agricultural biogas production but
             | never though about the potential of methane production from
             | waste water treatment.
             | 
             | Even more surprising is that the generated biogas is used
             | in the municipital gas supply in my town[1]. So I literally
             | cook with fecal products.
             | 
             | [1] https://www.stadt-zuerich.ch/energie/de/index/heizen-
             | kuehlen...
        
               | dopa42365 wrote:
               | You eat what you ate!
        
               | schainks wrote:
               | Related: https://www.youtube.com/watch?v=cVOT4xkkDAc
        
       | domtron_vox wrote:
       | We have e. coli as part of our gut biome right? Curious how
       | dangerous, if at all, it would be to get this modified version in
       | there. I have a hard time beliving it is very efficent so doubt
       | it would somehow electrocute you from the inside, but could cause
       | other issues.
       | 
       | I wonder how it compares to something like methane digesters in
       | production and ease to maintain. Seems like it would produce less
       | energy and not make nearly as good fertilizer, but be much less
       | finicky and not require an anaerobic environment or careful
       | temperature control.
        
         | zackmorris wrote:
         | One helpful way to think of it is that having a wide variety of
         | bacteria is what matters for a healthy gut biome.
         | 
         | If one species like e. coli flares up, maybe from food
         | poisoning, it can overwhelm the immune system. The other type
         | of food poisoning (like with botulism I think?) is where the
         | bacteria have already contaminated food with their waste and it
         | overwhelms the organs so the toxin reaches the body. But with
         | so many variations of e. coli already in existence, I would
         | expect the risk from an engineered version to be low.
         | 
         | -
         | 
         | That said, I lost my gut health in late 2018 due to a number of
         | factors including work stress, too many beers/cocktails and
         | ignoring my body's response when I ate stuff like almond butter
         | which I didn't know I was sensitive to. That punched holes
         | through my intestines and gave me leaky gut. Which allowed
         | gluten, lectins and lactose to pass the gut lining and trigger
         | my immune system. Now I'm sensitive to foods containing those
         | compounds, and they are in almost everything and especially
         | processed foods. It took me at least 3 years to recover and I
         | must largely avoid wheat and fast food now, which is.. annoying
         | to say the least.
         | 
         | Gluten sensitivity has reached such levels that many people can
         | only drink hard seltzer now, not beer. And having to offer
         | gluten-free options has become a burden on restaurants. What
         | most people don't realize is that gluten sensitivity can occur
         | at any age unexpectedly. I look at it now like smoking: every
         | time we eat grains, we run a small risk of becoming sensitized.
         | IMHO that's mostly due to the increased use of wheat and gluten
         | in processed foods, incentivized by the lowered cost of GMO
         | crops:
         | 
         | https://www.researchgate.net/figure/Correlation-between-incr...
         | 
         | This was all predicted by a small minority of scientists in the
         | 1990s and armchair activists like me who warned that GMOs would
         | have unintended consequences. TANSTAAFL except with GMO foods..
         | right.
         | 
         | I'd choose GMOs for industry over messing with our food supply
         | any day.
        
         | NtochkaNzvanova wrote:
         | Engineered microbes are almost always far less fit than wild-
         | type. They will survive best in a monoculture, and if they are
         | forced to compete with less hobbled strains they will usually
         | find a way to get rid of the engineered modifications in order
         | to grow faster.
        
           | worik wrote:
           | > Engineered microbes are almost always far less fit than
           | wild-type. They will survive best in a monoculture
           | 
           | True
           | 
           | But the article did not address this, it should have.
           | 
           | It will be the big question before deployment
        
           | __MatrixMan__ wrote:
           | I've always wondered how quickly this effect would ruin the
           | monoculture.
           | 
           | Suppose you're treating the engineered microbes like
           | sourdough starter: Add them to nutrient solution, wait for
           | desired effect, take a small sample, add to next batch.
           | 
           | You'd expect a selective pressure away from the engineered
           | outcome, such that after X batches, your samples are overrun
           | by wild-ish type mutants. But is that a merely academic
           | concern, something that might happen after 500 batches, or
           | are you out of luck by batch three?
        
       | etskinner wrote:
       | How exactly do you 'wire up' E. coli bacteria? Is the idea here
       | that we could somehow string a bunch of them together into a tiny
       | battery? Or is it more like using them as the electrolyte in a
       | battery?
        
         | p1mrx wrote:
         | They turn hydrogen+carbon and oxygen into protons, electrons,
         | and CO2.
         | 
         | The protons and electrons serve the same role as hydrogen in a
         | fuel cell.
        
         | schainks wrote:
         | It's more like using them as an electrolyte, but it acts like a
         | battery (you charge by adding waste, discharge by extracting
         | electrons), I guess? You run the bioreactor with some special
         | electrodes that bacteria like to touch, and then directly
         | harvest electrons from the medium as the little ones grow.
         | 
         | Mohammed and Melania (the lead researchers on the paper) are
         | both super talented scientists. I had the pleasure of meeting
         | them both in SF last year when they were on the west coast for
         | a conference.
        
       | m1n1 wrote:
       | One step closer to AI robots that can subsist by eating. :)
        
       | mpreda wrote:
       | I think researching in the opposite direction has more potential.
       | Let me explain:
       | 
       | what we want isn't to generate electricity through bacteria that
       | digests wastewater -- what we want is to feed electricity to the
       | bacteria that digests wastewater, just to enable that bacteria to
       | do it better, faster, and "wider".
       | 
       | Let's imagine I have a septic tank behind the house. I don't need
       | to find out how I can run a LED light from the bacteria in the
       | tank. What I want is to plug that biosystem to electrical power,
       | so that the septic tank biorection is 100x speeded up, in a 10x
       | smaller tank. Even if it uses up a few Watts of power.
       | 
       | And, once we do that, think of the possibilities that open up:
       | once you feed power into the biosystem, it becomes energetically
       | possible to drive bioreactions in the opposite direction from the
       | energy gradient, basically driving the reaction "up the hill"
       | with electrical power. Now that's something!
        
         | rcxdude wrote:
         | One important version of this idea is using electricity to
         | drive photosynthesis. If this manages to be even 10% efficient
         | it could massively increase the amount of calories available
         | without much increase in land usage (or ecosystem damage). Of
         | course I suspect this wouldn't produce particularly good food,
         | so it would probably be something of last resort.
        
           | adolph wrote:
           | > using electricity to drive photosynthesis
           | 
           | Like using electric lights in a shady warehouse?
        
             | dopa42365 wrote:
             | Or blasting UV light in perfectly legitimate warehouses.
             | 
             | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9551646/
        
         | whatshisface wrote:
         | You could check the idea by throwing sugar into the septic
         | tank.
        
           | mpreda wrote:
           | Yes, and that might help the reaction. Also heating the tank
           | to the optimum temperature (for the particular bacteria)
           | helps, optimum pH, etc. helps. But the point is to provide
           | the "help" with electricity directly.
        
             | whatshisface wrote:
             | What the sugar and electricity have in common that the pH
             | and temperature don't is the possibility of setting up an
             | ecosystem that crowds out the original one for nutrients
             | but doesn't process the waste, due to having another more
             | effective energy source.
        
         | ashin wrote:
         | You can do this to some degree with a septic tank aerator pump.
        
         | KarlKode wrote:
         | We actually do this as the basins populated with bacteria that
         | process our waste are heated to improve their metabolic
         | activity and speed up the process.
         | 
         | edit: in regular waste processing plants
        
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