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.
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.
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.
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).
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).
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.
If you want water mostly free of bacteria. Not if you want drinking water.
Apart from that, I can only shake my head. Because doing on your land freely, what you want is very much supported by my ideals - but those freedom should stop, where it directly affects other people outside your borders. Polluting the groundwater is obviously doing that.
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.
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.
And smell and taste are intertwined senses, that together are highly attuned to detecting and avoiding toxins, and finding and enjoying nutritious substances.
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.
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!
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
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.)
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.
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.
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].
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.”
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.
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.
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.
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.
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.
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.
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.
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."
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.
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
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.
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.
[1] https://en.wikipedia.org/wiki/Slow_sand_filter