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Just went through a local water treatment plant tour. Fundamentally, it’s pretty simple. This processing drinking water. The water comes in and the particulat

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 2y ago
Does the below ground part of the tank have pumps to supply water to the above ground part to get pressurization?
- whartung 2y ago
  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 2y ago
> 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 2y ago
  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 2y ago
    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 2y ago
    > 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/ 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 2y ago
      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 2y ago
        Indeed, that's the whole point of smell: detecting interesting or harmful things at low concentrations.
rascul 2y ago
Kinda interested now to see if I can get a tour of the facility that does my water.
zensnail 2y ago
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 2y ago
Don't you mean chloramine?

aftbit 2y ago

Does the below ground part of the tank have pumps to supply water to the above ground part to get pressurization?

whartung 2y ago
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 2y ago

> 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 2y ago
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 2y ago
  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 2y ago
  > 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/ 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 2y ago
    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 2y ago
      Indeed, that's the whole point of smell: detecting interesting or harmful things at low concentrations.

rascul 2y ago

Kinda interested now to see if I can get a tour of the facility that does my water.

zensnail 2y ago

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 2y ago

Don't you mean chloramine?