[HN Gopher] Bog gravel filtration: Water cleaned by Mother Natur...
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Bog gravel filtration: Water cleaned by Mother Nature (2015)
Author : ciconia
Score : 85 points
Date : 2024-06-20 03:25 UTC (1 days ago)
(HTM) web link (www.pondtrademag.com)
(TXT) w3m dump (www.pondtrademag.com)
| Animats wrote:
| See the related "slow sand filter".[1] Slow sand filters are
| still a good water treatment method if you have enough space.
|
| [1] https://en.wikipedia.org/wiki/Slow_sand_filter
| whartung wrote:
| Just went through a local water treatment plant tour.
| Fundamentally, it's pretty simple.
|
| This processing drinking water.
|
| The water comes in and the particulates within it carry a
| negative ion charge. The water passes over an agitator, and a
| combination of ferric chloride and some kind latex are mixed
| with the water.
|
| The water then flows through a long channel. At this point the
| negative charged particles bind with the positive charged
| chemicals. The combinations then simply precipitate out in the
| long channel. At the end, small channels draw water off just
| the first few inches of the larger channel.
|
| This water goes to a combination aggregate and sand filter.
| It's not very deep, about 3 feet total for both.
|
| The resulting water is 99+% pure now.
|
| It moves on to a large activated carbon filter. We're talking
| 10 feet deep. Like a water pitcher filter. This is a recent CA
| requirement, installed in 2005. Designed to remove some
| specific by products.
|
| The water then goes through a large UV system to kill what's
| left, and is finally injected with some chlorine. The chlorine
| is preventative to deal with anything that may potentially be
| introduced later in the system.
|
| I don't know when they intrythe UV part, but the way it's laid
| out, seems like that came with the carbon filter system.
|
| That means that prior to 2005, the aggregate and sand filter
| was considered good enough, augmented with the chlorine. But
| they never considered the chlorine as part of the purifying
| process, simply precautionary.
|
| It was very interesting, and I thought pretty simple
| conceptually. The trick is the actual engineering of the actual
| plant and respective water system.
|
| I found it interesting to learn that the large water tank near
| me, which roughly measured at 5M gallons is actually only 1/3rd
| above ground. It's a 16M tank, one of the largest in the
| system.
| aftbit wrote:
| Does the below ground part of the tank have pumps to supply
| water to the above ground part to get pressurization?
| whartung wrote:
| All of the water delivery is gravity fed. We live on the
| slope of an alluvial fan. Water is pumped as/if necessary
| to the various reservoirs, but from there they rely on
| water drop for delivery.
|
| The tank may well have two sets of pipes to service the
| closest homes, some closer to the surface with others
| buried deeper(assuming those homes are even serviced by
| that tank). But I'm less than a quarter mile away and well
| below the bottom of the tank.
|
| It's steeper here than it looks.
|
| They say they can move water from anywhere to anywhere in
| the system through a combination of pumps and gravity, but
| all consumer delivery pressure is gravity based. The water
| pressure at someone's house is based on their distance in
| height from their servicing reservoir.
|
| If they were to move water from the lowest part to the
| highest, it would take 8 lifts of the water. Electricity is
| a significant expense to the system so minimizing pumping,
| for any reason, is a priority for them.
|
| An interesting trivia bit is that, according to them, where
| our system has 8 lifts, the CA aqueduct has a total of 11
| in its system.
| SoftTalker wrote:
| > they never considered the chlorine as part of the purifying
| process, simply precautionary
|
| In many parts of the world they do not add chlorine. Our
| water tastes and smells like a swimming pool in comparison.
| bongodongobob wrote:
| I've been all over the US and no where has it smelled or
| tasted remotely like chlorine. A quick Google says the high
| end is 4 ppm. If you think you can taste or smell that,
| you're lying to yourself.
| lagniappe wrote:
| In my area the smell of chlorine and chloramine is thick
| on some days (usually after storms and floods). I'm a
| reefkeeper, I see it in my water tests too, on those days
| I don't use my RO DI filter because I don't want the
| extra stuff going in. You can smell it under a hot tap as
| a sickly sweet smell.
| mlyle wrote:
| > If you think you can taste or smell that, you're lying
| to yourself.
|
| I most certainly can smell it.
|
| https://www.ncbi.nlm.nih.gov/books/NBK579463/
|
| "Most individuals are able to taste or smell chlorine in
| drinking-water at concentrations well below 5 mg/l, and
| some at levels as low as 0.3 mg/l."
| dmurray wrote:
| And you can taste/smell lots of things far below 4ppm -
| example: farts - so appealing to "this looks like a very
| small number so you must be lying to yourself" is
| nonsense here.
| mlyle wrote:
| Indeed, that's the whole point of smell: detecting
| interesting or harmful things at low concentrations.
| mythhabit wrote:
| For many people that live where there is no chlorine in
| the water, it's immediately obvious when there is added
| chlorine to the tap water. I'm not sure I can taste it,
| can't remember I've actually tried, but I can absolutely
| smell it.
| bux93 wrote:
| I had coke that tasted like a swimming pool in Minnesota.
| I had no reason to suspect it would, so it's not
| something I was convincing myself of. It came from a
| machine that used tap water of course, rather than from a
| bottle or can.
| ohmyiv wrote:
| In L.A. I can tell. I lived in Washington state for a
| couple of years and when I got back to L.A., I could
| clearly smell it. As for the taste, I don't know if it's
| chlorine I taste, but it does taste really different. I
| can also really tell the difference from most Bay area,
| specifically Hetch Hetchy water, and L.A. municipal.
|
| If think people can't tell the difference, you're lying
| to yourself.
| throwbadubadu wrote:
| It is a matter of getting used to, childhood imprint.
|
| Most Europeans will smell and taste the chlorine
| immediately, even in a coke in a fast food chain in the
| US where they mix that tap water in, or even just in ice
| cubes.
|
| This conditioning works also the other way round. Read
| often that Americans usually find the tap water in Europe
| to be not "fresh", because of the missing chlorine.
|
| I don't think there is any self-lying involved. People
| notice it the first time going and trying, certainly not
| because they have been subconsciously indoctrinated.
| Personally strongly confirm!
| amluto wrote:
| I suspect that the prominent "eww my food/drink smells
| like chlorine" problem isn't the tap water. Most soft
| drink machines have filters that are quite effective at
| removing chlorine and chloramine.
|
| Restaurants (at least in the US) are, IMO quite sensibly,
| required to sanitize dishes between uses. This can be
| done using chlorine or similar chemicals in a "low
| temperature dishwasher" or using heat in a "high
| temperature dishwasher". The former leaves a disgusting
| residue that can take quite a while to degrade by itself.
| Those freshly washed, still wet plastic cups next to the
| drink machine, in a restaurant with a low-temp
| dishwasher, will make anything you put in them taste like
| chlorine or, worse, nitrogen chlorides. But they won't
| give you nasty foodborne infections.
|
| You can somewhat mitigate this by rinsing the cup before
| filling it.
|
| (There is also some evidence that rinse aid, which
| intentionally leaves a residue on cups and dishes, is
| quite bad for you.)
| selimthegrim wrote:
| Commercial rinse aid
| nanidin wrote:
| Alcohol ethoxylates that were identified to cause
| epithelial inflammation and barrier damage[0] are listed
| as ingredients in consumer dish detergents[1] and rinse
| aids[2].
|
| [0] https://pubmed.ncbi.nlm.nih.gov/36464527/#:~:text=The
| %20alco....
|
| [1] https://smartlabel.pg.com/en-us/00037000982067.html
|
| [2] https://giantfoodstores.com/product/finish-jet-
| dry-3-in-1-ri...
| selimthegrim wrote:
| Your search and that of the other reply missed the
| previous sentence "The expression of genes involved in
| cell survival, epithelial barrier, cytokine signaling,
| and metabolism was altered by rinse aid in concentrations
| used in _professional_ (emphasis mine) dishwashers."
| amluto wrote:
| Here's one of the studies:
|
| https://www.sciencedirect.com/science/article/pii/S009167
| 492...
|
| And here's the ingredient list for a major brand of
| residential rinse aid:
|
| https://www.rbnainfo.com/product.php?productLineId=654
|
| It sure looks like the same stuff.
|
| If you have low enough water hardness and TDS, then rinse
| aid serves no purpose and you can just not use it. Even
| with higher hardness, the main benefit is just aesthetic.
| meristohm wrote:
| We add clear vinegar to the rinse aid container, but only
| when the particlar detergent (we don't always buy the
| same one) leaves residue. Seventh Generation (sadly
| bought out by Unilever) still makes decent detergent.
| However, what's the environmental impact at and around
| the factory? I'd rather wash fewer dishes by hand (I've
| measured, after our old dishwasher broke, and can wash a
| day's dishes with less than 1.7 gallons of water) than
| contribute to demand for a manufactured item with non-
| zero embodied energy and the boxes and boxes of detergent
| scaled to hundreds of millions, perhaps billions.
| Bloating wrote:
| Just came back from europe. Couldn't tell any difference
| in the water, but found it interesting to see many of the
| hotels had free self serve filtered drinking water
| stations which gave me the impression something might be
| wrong with the tap water there
|
| https://www.cokesolutions.com/content/dam/cokesolutions/u
| s/d...
| meristohm wrote:
| Chloramine, then, which is what Minneapolis uses, last I
| checked, and I could smell it relative to water that had
| boiled or sat out long enough. Our noses aren't as
| sensitive as a dog's, granted, but still a useful sense.
| lukan wrote:
| Yeah, that does not make much sense to me. (Unless the
| producers of bottled water are in on this).
|
| In europe one can mostly dring good water from the tab.
| Only in some places (e.g. most of spain) chlorine is added
| and the difference is horrible. I could not drink that from
| the tap (and the spanish also buy bottled water as far as I
| know).
| wongarsu wrote:
| From what I gather (anyone feel free to correct me) the
| US doesn't have as good programs or regulations to
| protect drinking water sources. In Europe you will
| frequently see areas where actions that could pollute
| ground water are prohibited, ranging from restrictions on
| what you are allowed to build and store to what is
| allowed to drive through the area. In the US this is more
| difficult to do.
|
| There is the Clean Water Act. But that only really covers
| navigable waters, or a lesser degree all surface water.
| But it doesn't protect ground water. Then there is the
| Safe Drinking Water Act which sets standards for how safe
| the water out of the tap has to be. But how do you get
| safe water if it's difficult to protect your water
| source? Chlorine is the cheap and effective answer.
| bayindirh wrote:
| We do. As a result, if we cook or make tea with tap water,
| you get a hot swimming pool smelling liquid in your
| cup/bowl.
| brazzy wrote:
| I've also heard about it being done conditionally, only
| when problems with bacterial contamination are detected (of
| course this requires a stringent testing regime).
| Scubabear68 wrote:
| I live in a very rural area in NJ, 90% of residents are on
| well water. We live in an area where a lot of fractured
| bedrock, the fractures serve as natural filtration. Net
| result is our water tastes great with no chlorine or other
| filtration.
|
| Caveats - you need to ensure your well is deep enough to
| avoid surface contaminants, ours is about 180 feet deep.
| Also you need testing for new wells, as an example a few
| miles from us there is heavy arsenic concentrations that
| need to be filtered out.
| rascul wrote:
| Kinda interested now to see if I can get a tour of the
| facility that does my water.
| zensnail wrote:
| The combination of ferric chloride and latex is what's called
| coagulation flocculation treatment. The coagulant, in this
| case the ferric chloride, neutralizes the charges on
| suspended particles in a liquid, causing them to clump
| together into larger aggregates (flocs) that can then be more
| easily separated from the liquid through sedimentation or
| filtration.
|
| The latex in this case is the flocculant, assist in binding
| together the microflocs formed by coagulation into larger,
| more stable aggregates known as flocs. Flocculants often work
| by bridging the particles through long chains of polymers,
| effectively linking the microflocs into larger clusters.
|
| After the coagulation and flocculation process, the water
| usually enters a large settling basin where the flocs
| gradually settle to the bottom, resulting in clarified water.
| sidewndr46 wrote:
| Don't you mean chloramine?
| walthamstow wrote:
| I think these are what is used in London. The water treatment
| plant near me (Coppermill) has dozens of rectangular sand pits
| twic wrote:
| If I understand correctly, the way these work is that
| microorganisms create a biofilm, and then the biofilm filters
| the water. The pore size is incredibly small, so particulates
| and bacteria and so on are filtered out.
|
| In which case, I wonder if you could make a more space-
| efficient version by producing biofilms, or something similar,
| on an industrial scale. Whether in bioreactors optimised for
| film production, or just by making great sheets of agarose gel
| or something.
| stubish wrote:
| All the information I find relates to fish ponds. I'm trying to
| work out if a bog filter is a good idea for a frog pond, or if
| the clearer water will make things worse for tadpoles.
| knodi123 wrote:
| frogs are super sensitive to environmental contamination, so
| clean and clear is fine. as long as it's stagnant.
| j16sdiz wrote:
| Frog pond are _loud_.
| Arrath wrote:
| Frogs in the night are the sound of home and childhood. I
| love it.
| po wrote:
| This is great advice and I've actually built ponds on this
| principle in the past. It works well. There are tons of Youtube
| videos on this subject as well. The channel ozponds is pretty
| good for this.
|
| What I am now interested in is the construction of spring boxes
| and finding and digging a natural spring from a wooded area. I
| used to do this when I was younger, but I've found that while the
| internet generally has all kinds of new techniques that I wasn't
| aware of, unfortunately, I haven't found a great source of info
| for this topic yet.
| threatripper wrote:
| "Learn from the mistakes of others. You can't live long enough to
| make them all yourself."
|
| That's some good advice.
| atoav wrote:
| As an university educator I would add: Take risks and try out
| things at times/places where you can afford to fail, e.g.
| during your studies.
|
| Nowadays too many students put their chips only on safe-bet-
| projects during their study, which traditionally would be the
| one time in their lives where they could really try and fail
| etc.
|
| Sure a lot of that is due to economic constraints, which have
| gotten catastropically worse in the past decades, but trying
| out things that you know could fail means you are operating at
| the edge of your abilities, rather than in an area that is
| safely covered by them. And traditionally that is where the
| interesting lessons are learned.
|
| Learning from others mistakes is a good thing as well, but for
| that they also have to try things that aren't safe bets.
| pictureofabear wrote:
| There is a great bias against failure, even for seasoned
| academics. I always liked this quote from Feynman
|
| "If you've made up your mind to test a theory, or you want to
| explain some idea, you should always decide to publish it
| whichever way it comes out. If we only publish results of a
| certain kind, we can make the argument look good. We must
| publish both kinds of result."
| mianos wrote:
| If you are spending masses of money and time on something,
| there is little to no chance anyone in their right might
| would take any more risk than they have to.
|
| If you are living on a trust fund, sure, give something risky
| a try.
| atoav wrote:
| I might have to add that I am an educator at an art
| university and work in a country with nearly non-existent
| admission fees.
|
| Artists that don't risk things during their studies will
| have a hard time producing interesting things.
| 123pie123 wrote:
| this is interesting if it's true
|
| https://www.youtube.com/watch?v=nSBwJNDDUfc
| hadlock wrote:
| Sponge filters do this same task as bog filtration as well, at a
| much smaller scale. A sponge is shaped like a cylinder, then a
| 1cm hole is punched through the center. An air tube goes down the
| middle, and a 4cm "chimney" sticks up from the hole to improve
| flow characteristics. The whole contraption is immersed in water.
| The result is that the bubbles travel upwards, pulling some water
| with them, and exits the top of the chimney. This water is
| replaced by water outside the sponge. The sponge acts as both a
| mechanical filter, but also as a high surface area for microbes
| to live and process waste.
|
| Bog filters work on a much larger scale, but sponge filters have
| been replacing "hang on back" filters in the aquarium hobby
| pretty rapidly over the last couple of years. It also helps that
| sponge filters only cost about $10 and have no moving parts
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