Question about well chlorination system

[Deude Mann]

Hello all. First time post. I have been reading up on different methods of well water chlorination and have a couple of questions about implementation of a chlorination system.

First, here is a simplified diagram of my well setup as it currently stands. This has been in place and operational for years.

Here are the details of my system...

This is a private well that is used for a single family residence. I want to add a chlorination system in order to deal with algae growth in the MAIN TANK (see above) and control general contamination; I understand that chlorination is not a cure-all but after reading up on the pros and cons of chlorine vs. ozone vs. UV, chlorine is what I would like to do.

The plan would be to purchase a chemical injection pump and connect it to the control circuit for the Well Pump so that the injection pump runs when the well pump is refilling the MAIN TANK. Based on measurements of residual chlorine, using a proper chlorine gauge, I would adjust the chlorination amount to hit a level for potable water, which I believe is 0.2 to 1 ppm (?).

The water this system produces runs through a resin-tank type water softener that is located in the main house. Our water here is really hard so the softener helps extend the life of the water heaters; it is common here for them to completely fill with calcium in 5-10 years, like someone filled it with concrete. I know I need to be careful with chlorine content with the water softener to protect the resin. It has a bypass that I use if I shock the well or the MAIN TANK.

The water post-softener is only used for bathing, washing clothes, flushing toilets, watering the yard, etc. The only water we drink, cook, or make ice with comes from a single point of use, under the sink, 5-stage RO system that is also post-softener.

I can do all of the chlorination system work myself since, shorting of pulling the pump from the well (requires a crane) I do all of the well plumbing and electrical work myself. I want to keep the initial equipment cost under $1000. From what I have seen there are injection pump-tank systems out there for much less than this, in the $300+ range.

The well pump produces about 600 gph when filling the MAIN TANK. This is based on a rough measurement I made recently when I filled the tank from completely empty to 2400 gallons. It took about 4 hours.

I hope that information makes sense. If not let me know and I will clarify.

Now the questions:
1. It seems to me that since there is a lot of storage time in the MAIN TANK that this is the point in the system where the chlorine should be added. This is by far, except possibly for the well itself, the most stagnant part of the system so the chlorine should have plenty of time to do its thing. Am I correct that this is the place to add the chlorine?
2. I would presumably use a chemical injection pump, with a chlorine holding tank, to add the chlorine into the system as it flows into the MAIN TANK. Does it make any significant difference if I inject the chlorine into the water line between the Well Pump and the MAIN TANK, or straight into the main tank?
3. Are there any additional suggestions as to what else I might add to this?
4. Any recommendation on which brand of injection pump I should be looking at? I'll pay extra to buy quality as long as it is not exorbitant. I'm not going to pay $10K for a nuclear power plant rated industrial pump for example.

Thanks in advance

 

[Reach4]

Your plan looks sound. FYI, for your math, 8% chlorine bleach is 80000 ppm.

Why not eliminate the cistern? There can be good reasons, but what is your motivation?

If you draw the water directly from your deep well, sanitize your well and plumbing. Nothing stagnant. Nothing growing.

 

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[Deude Mann]

One more comment... Adding chlorine directly into the well may not be desirable. There are four VERY HEAVY gauge wires running from the well head down to the pump. Again, it is about 800 feet below grade, no joke. I know this for a fact. The wires are taped to the well pump pipe at ~40 foot intervals to help support the weight of the cables. Based on anecdotal evidence, introducing chlorine from the top of the well head can degrade that tape and cause it to fail. Very expensive problems can result when this happens.

 

[Reach4]

One more comment... Adding chlorine directly into the well may not be desirable. There are four VERY HEAVY gauge wires running from the well head down to the pump. Again, it is about 800 feet below grade, no joke. I know this for a fact. The wires are taped to the well pump pipe at ~40 foot intervals to help support the weight of the cables. Based on anecdotal evidence, introducing chlorine from the top of the well head can degrade that tape and cause it to fail. Very expensive problems can result when this happens.

I understand your concern.

Degrading is a function of chlorine strength but also time. I was proposing to do the treatment once, but effectively, after working on the system. Then it could be years before another sanitizing is called for. I certainly don't have data for you on that. It has been a few years for me so far. My well is not nearly as deep as yours.

 

[Deude Mann]

Your plan looks sound. FYI, for your math, 8% chlorine bleach is 80000 ppm.

Why not eliminate the cistern? There can be good reasons, but what is your motivation?

If you draw the water directly from your deep well, sanitize your well and plumbing. Nothing stagnant. Nothing growing.

OK good, glad to hear I am on the right path.

On your cistern question... Good question. It is very handy to have that much water on hand for at least two reasons:
- One, if the main pump fails, it can be a week-long ordeal finding a well company, pulling the pump (takes 2-3 hours, a crane, and two people working really hard to do it that fast), etc. So the tank buys time for all of that to happen. The house can use the tank water until the well is fixed. Last time my pump failed (during a bad drought, pump had to be lowered) it REALLY sucked suddenly running out of water so I added the Main Tank right after that happened.
- Two, we do not have fire hydrants out here, and are covered by a VFD. Fires can get out of control quickly in the hill country so it is a good idea to have a lot of water on-hand for firefighting.
- The cistern also greatly reduces the amount of wear on the well pump since it cycles on and off much less than it does just filling the small pressure tank. Anything that helps pump life is good since any pump replacement runs into the thousands of dollars due to the depth.

As far as chlorinating the well I have done this to shock it a few times over the years but hesitate to do this full-time due to my post above. Risk of well damage.

 

[Reach4]

One, if the main pump fails, it can be a week-long ordeal finding a well company, pulling the pump (takes 2-3 hours, a crane, and two people working really hard to do it that fast), etc. So the tank buys time for all of that to happen.

Very good reason.

Two, we do not have fire hydrants out here, and are covered by a VFD. Fires can get out of control quickly in the hill country so it is a good idea to have a lot of water on-hand for firefighting.

An alternative would be to have the tank with a slow-release swimming pool chlorine tablet or two. That water would only be used for fire fighting under normal conditions.

Various carbons, such as GAC can remove chlorine. Chlorine will precipitate various things, such as iron and manganese, and that is often the main motivation for chlorine. The carbon tank removes the residual chlorine.

I was not suggesting full-time chlorination in the well. Some do that by dropping pellets with a feeder. I was thinking of something like this https://terrylove.com/forums/index....izing-extra-attention-to-4-inch-casing.65845/ where you are done in about a day. I guess that could take longer with an 800 ft well to circulate and purge.

 

[Deude Mann]

OK gotcha. I have done a shock like that before, that is adding bleach to the well and circulating it through the well. It works for sure. The Texas Agricultural Extension Service (part of Texas A&M) has a good procedural writeup on how to do this. In my case it takes a couple of days to flush all of the bleach out of the well once the circulation part is done.

Thanks for this input, it is helpful. Any recommendations or FAQs on who makes a good chemical injection pump setup?

 

[Valveman]

As long as the well is sealed properly it shouldn't need chlorine very often if ever. What you are proposing is very common with cistern storage tanks. I would inject the chlorine in the line coming from the well before it dumps into the storage tank. This should help stir it up a bit.