Chlorination after Installing a Well Pump

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I am planning to install a well pump in a water well in a rural area which has no other water source.

Should I perform shock chlorination in order to avoid Coliform bacteria contamination or should I test the water for Coliform bacteria after installing the pump and react only if the test is positive?

How do I best approach the installation and maintain water quality?

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30 Answers

This note from WEDC might ...

This note from WEDC might help you.

http://www.who.int/water_sanitation_health/publications/2011/tn1_cleaning_disinfecting_wells_en.pdf

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First the analysis to know ...

First the analysis to know the level of contamination then regular dosing to kill the bacteria and then anything else. Shock chlorination is the solution for short period.

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After well has been ...

After well has been constructed (assuming proper encasement and sealing has been made) chlorination is done on line prior to distribution.

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collect sample after ...

collect sample after dewatering entire water from well to study quality.The probable sources of bacterial contamimation shall b identified 4 elimination if possible

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The short answer to your ...

The short answer to your question is Yes.  However, as some have already mentioned more information is needed.  I do not believe this is a treatment question as many others have assumed, but that would be a next step.

Is this well intended for single private household usage?  Additional requirements may apply for commercial or community usage.

What are the well construction details?  Dug/drilled/bored, casing type and integrity, annular seal integrity, well surface condition?  Basically is the well protected from surface contaminants (surface water entry, animals/insects, vegetation intrusion/tree roots, etc.)?  This is essential to prevent ongoing bacterial contamination.

Has the well been used regularly or left abandoned for an extended period of time?  If the well has been sitting for a while the water within the casing is likely to be stagnant.  Install your new pump and run it for an extended period to develop the well.  You will want to do this even if the well has been used regularly, as introducing your new pump will stir up the water column.  Ideally you should run the pump until the water is clear, which could take several hours. If your well has poor recovery be careful not to run your pump dry.

Once you have sufficiently developed the well, yes, complete the shock chlorination process.  I'm not sure where you are located, but in Canada there are several guidance documents available on the proper procedures.  Generally you add a calculated volume of chlorine bleach based on the well dimensions, run your pump (and household taps if connected to house) until you smell chlorine, allow everything to sit for 12-24 hours, and then flush water to an outdoor area where it can infiltrate into a non-sensitive vegetated area (NOT to a septic system or surface water feature) until chlorine dissipates.

Once chlorine has been fully flushed from the well (free chlorine residual

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Better to get the water ...

Better to get the water tested first to see the amount of bacterial contamination. After that you have to go for online continuous dosing until you get the bacteria free water from the source. One time shock chlorination can solve the issue for some time only.. This is my opinion.

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Hi Bojan. Seems you have ...

Hi Bojan. Seems you have received many correct answers below. 

If possible filtration is the best way to reduce organic matter that acts as a food source for bacteria. Water is also seasonal so the analysis you have now could change in future but regardless is important.

After filtration you could look at a storage tank for the water and place a UV-C light in the tank. The problems with inline UV-C is that the lamp needs 15-20 min to heat up and have enough UV-C emitted on the passing water.Always remember that about 1/3 of the wattage is UV-C and wear protective eyeware.

www.ozoneuv.co.za offers many chemical free water sanitation methods. 

Please see attached spec sheet on the Sani Submersible UV-C 

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When testing the borehole it ...

When testing the borehole it is necessary to run the borehole for a suitable period to waste first so that the sample is representative of long term production. Typically without doing this the metals such as iron will be higher, turbidity elevated and there may be contaminants resulting from the well drilling.

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First of all, you ​analyse ...

First of all, you ​analyse water for detail analysis for heavy metals bacteria, Hardness & total Coliform. You can use cheap Solar Water system, that is approved by TUV for producing mineral drinking water. For pathogenic microorganism’s chlorine, chlorine dioxide, and ozone are used. Chlorine tablets are also used. physical disinfectants include ultraviolet light, electronic radiation, and heat are also used.

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Normally in a none ...

Normally in a none contaminated field, a bore water is sufficient to be treated by chlorination or combined with a MF filtration. If it were contaminated field, it would require a RO polishing.

 

The chlorination in a remote area can be normally treated by a tablet dissolving system with more than 30 minutes contact period. The dose rate should be to guarantee a free chlorine at approx. 0.5 ppm in the water.

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1 Comment

Firstly there is the issue of ...

Firstly there is the issue of needing an analysis to base decisions on. If there are coliforms present then it is likely to need rather more than shock treatment and something more continuous.
Then there is the installation of the pump and pipework. This should be flushed out and shock chlorinated to ensure that contamination that may have entered while it was in pieces is removed.  

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You will often get a lot of ...

You will often get a lot of conflicting advice on how to treat a borehole.  The analysis is not optional but absolutely essential, not only for the bacterial content but the physiochemical content.  There may be metals in the water such as arsenic, which will require one form of treatment, there are boreholes containing iron or manganese, which will require oxidising prior to specialised filtration using green sand, base iron removal or fylox.  There may be suspended solids present which may be filtered, and the pH may need to be corrected if it is acidic.  Filtration may well help reduce any bacterial load in the water.  If there is a significant bacterial content, then it should be pre-filtered to assist in bacterial removal.  Dryden Aqua have produced a filtration media AFM, which works like sand but doesn't get colonised by bacteria.  UV is very good at reducing bacterial levels and will kill protozoa such as Giardia or Cryptosporidium (which should be pre-filtered first) but there is no residual effect so bacteria can grow in the water on storage.  If there is iron or manganese present then chlorination may be used as an oxidant, I haven't successfully used ozone, but there needs to be a reaction time between injection and filtration.  Chlorine is effective at controlling coliforms and many bacteria at relatively low levels on clean water.  The starting point is the analyses.  From there, you will know what needs removing.  It will also dictate how the water is treated and whether further treatment is required to control corrosion in the pipes.   

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We need more information on ...

We need more information on the construction of the well and the method, and type of pump for installation. Is this a hand dug well? Is the well sealed or subject to surface water intrusion? You can do all the testing you want, but first must ensure the integrity of the well.

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Dear Bojan, Definitely you ...

Dear Bojan,

Definitely you need to analyse water if it is for human consumption. I suggest at least Total Coliforms, heavy metals and hardness. If water is hard you will probably have carbonates precipitation in the downstream. Also I recommend a brief analyse of your well ¿How depth it is?  Do you have any potential source of impact in the aquifer (septic tank? for example?)

If it is located in rural area you may chose an easy and economic alternative...I agree with TUV, however everything will depend on your analytical results...groundwater is normally free of coliforms or other if the aquifer is depth enough and no impacted by external sources. 

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Firstly, you should take ...

Firstly, you should take sample of your water at the source then have it tested for possible pollutants ( eg. heavy metals,...), then from the result you will know whether a kind of treatment is needed before distributing it. however if water doesn't contain any pathogen or harmful substance and yet it has to pass through a pipeline from the source to the end users, you will need to either do the chlorination to help the desinfection along the distribution line just in case any pathogen get into that network is deactivate and leave the people safe  or you can use the TUV to achieve the same results.

Have a nice day.

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Better get it tested before ...

Better get it tested before any chemical treatment 

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I suggest that you use ...

I suggest that you use Triple7 AquaSmart https://envirofluid.com/worksafe-environmental-chemistries/water-wastewater-treatment/triple7-aquasmart as the safe alternative to chlorine and if the bore develops Iron Bacteria  use Triple7 Envirobore https://envirofluid.com/worksafe-environmental-chemistries/water-wastewater-treatment/triple7-envirobore - for further information please email sales@envirofluid.com .

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You can use the cheap Solar ...

You can use the cheap Solar Water device, that is approved by TUV for producing mineral drinking water from any kind of sources, no maintenance, easy use, 20 years life span, and 100% natural process. Please ask me if u need more infos

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Get your sample tested first ...

Get your sample tested first for Ecoli and chemical analysis so that you can determine your dosage requirements,I would advise super chlorination of the well for 24hrs then pump this water out then continue on with dosing of chlorine making sure FAC is at 0.3-0.7mg/l

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Hi Bojan, I suggest you ...

Hi Bojan,

I suggest you perform a microbiological and physicochemical analysis of the raw well water before installation of the pump. If the results are friendly (safe), you can instal the pump and do your simple disinfection. If the results are not very friendly (unsafe water), you might need to instal other simple treatment equipment (like multimedia filters, etc)  that can rid the water of the contaminants. Very important if the water is for drinking.

Regards

Justin

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