Chlorine Tank/Distribution in Water service in Colombia, S. America 2

[controlnovice]

I live in Colombia, South America. I was an EE and Controls Engineer in the US for 30 years.

I volunteered for our local water system where we live. We're at 1700m altitude outside a small village.

I've been able to fix several problems in our water system, but I'm not sure about this design and what it's for.

We mix 2kg of granulated/powder chlorine in water in a bucket, then fill these two tanks (or basins) with the mixture as evenly as possible, then fill the rest of the tanks with water. I've only been volunteering for a few months, so am following what the 'fontanero' (plumber) has done for 30 years. The installation is about 60 years old.

The chlorine water then drips through an IV tube into the water tank below the chlorine tanks which is then distributed through the system. We take chlorine samples every day to verify the chlorine level and adjust the IV drip as needed. There is no electrical power in the area of the tanks...it's halfway up a mountain.

What I don't understand is the design of the two chlorine tanks. As you can see in the photo, the IV drip is from one tank. The tank further away has a 1/2 inch pipe at it's base that empties into the closest tank.

What is the reason for two tanks?

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[EdStainless]

My guess is that they wanted (found that they needed) to limit the head in the Cl tank.
If the fluid is deeper then as it drains the flow rate will change more along with the greater head change.
Or is it just to give them some extra capacity in case that they need it later.

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P.E. Metallurgy, consulting work welcomed

 

[LittleInch]

Something lost in the mists of time.

Makes no real sense.

What is the white pipe used for?

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[controlnovice]

What is the white pipe used for?

White pipe at the bottom of the tank (halfway up the side of the wall is the bottom of the chlorine tank/basin) is the outlet that drains into the water tank below.

The 1.5" pipe (and white 1/2" pipe) at the top is to fill the chlorine tanks with water, since we mix the chlorine in a 20 liter bucket (stirring it frequently before dumping it into the tanks), we need to fill the tanks to the brim with water. It comes from a dammed stream about 2 meters higher. We have to add chlorine every 3-4 days. The green fabric sitting over the basin, under the pipe, is used as a filter as the water can be dirty sometimes. The 1/2" white pipe is also used to fill buckets with water for cleaning, etc... It's much closer to the edge and easier to use for filling.

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[FMJalink]

Hi controlnovice,
I am not an expert on these systems, but have have seen several for circumferences adapted solutions.
Is there (now) an internal connection between the two tanks?
If not, or later added, then I think the original intention was to use the tank at the back (the one with the 1.5 inch pipe) as preparation tank, where the solution can be brought up to specification. There after I think the prepared solution had to be entered in or added to the second tank (dosing tank) by means of a bucket.
If there is a later added connection between the two tanks, I would guess someone did change the original system to a batch like system allowing more time between having to prepare a new solution.

 

[hacksaw]

You might contact some of you former coworkers/employers to track down a party and resources to provide advice.
You want to be careful in attempting to automate the existing manual process.

 

[controlnovice]

Is there (now) an internal connection between the two tanks?

Yes, there is a 1/2' pvc pipe at the base of the two tanks that allows equalization. It was there from the beginning...according to the 'plumber' who has worked here for 30 years. I just don't understand why there would be two tanks, and not one.

You want to be careful in attempting to automate the existing manual process.

There is no energy/electricity in the area to automate. Although I have thought about solar, batteries, water flow meter and a small pump for the chlorine.

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[pierreick]

Hi,
Probably easier to homogenize manually (small tanks)
Breizh

 

[LittleInch]

You say the system is 60 yrs old, so the original may have been different from what the plumber knew.

Maybe it started as one tank and then they doubled the volume, but while building the second one needed the first to keep working. Or originally one tank and then someone sub divided it. There is no process reason I can see.

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Also: If you get a response it's polite to respond to it.

 

[georgeverghese]

Have no experience in water treatment, but my guess is the first tank ( the one directly beneath the 1.5inch fill line) is a combination prep settling tank / chlorination tank.
Step 1: Aluminum sulphate or ferrous/ferric sulphate is added to this tank to settle out solids which would sink to the bottom.
Step 2 : There must be some way of draining out this semi solids layer to leave a clear liquid in this prep basin.?
Step 3: Next, add the 2kg of hypochlorite powder and mix before transfer to the tank in the foreground through the equalisation line.