Friday, August 28, 2015

Well Water Treatment for Coliform Bacteria

farm well water


We have a small cabin in the country, and its near a farm.  Our well recently tested positive for coliform bacteria.  What do you recommend: clorinator or ultraviolet light treatment?  Which is better?

Joey B.
Springfield, Illinois

Hello sir,

Bacteria contamination is a serious problem to deal with, but we can definitely help.  There are a few options available for treating this situation, and the two most common are UV treatment and chemical treatment. 

coliform bacteria

Ideally, to be certain you are achieving proper disinfection, we always recommend using both chlorination and UV sterilization for a double barrier effect.  However, complete sterilization can be achieved with one or the other.  Either way, it is good to proceed with caution and plan accordingly.  I am including some more information on both options below.

The first and more common option uses chlorine injection with the use of a metering pump, which provides extra strength oxidation for coliform bacteria, as well as strong odors and high levels of iron and manganese (which can be linked with sulfur odors).  

The chlorine would then feed into a contact tank to provide enough time for the solution to react with the bacteria in the water, disinfecting it for good.   You could, as an option, send the water through a carbon filter to then remove the chlorine taste and odor completely.  Because chlorine injection maintains a regular residual of chlorine throughout the pipes of your home, it is the more reliable and safer method.

The second, less reliable though quite popular method is a UV system for your whole house.  Ultraviolet sterilizers work by exposing the cell walls of an organism to intense UV light which disrupts the genetic material and prevents the organism from reproducing. 

UV effectively destroys bacteria and viruses but is limited by the clarity of the water. UV only works on water that is clear and has a high UV transmission rate. Unlike chlorine there is no downstream residual disinfection.    Note that a UV sterilizer alone will have not have fail-safe controls built into it.  These UV sterilizers are rated as NSF certified, but are not Class A, meaning they don’t have a light monitor to monitor the UV transmission levels in the water.   We do have Class A NSF sterilizers available for around $1800 but that price may not be practical for a weekend cabin.  If the UV light were to burn out or become unplugged, you would have no way to know if the water was no longer safe.

Having two barriers (chlorination PLUS UV) works best.

Pretreatment for iron, sediment and excessive hardness minerals is recommended.
Check out the diagram below to have a clearer view of how it works.
water treatment diagram


Chlorinator Package Precision-24 + 15 Gal Solution TankPrecision-24 Chlorinator Package with Solution Tank:     Price:  

Can be either 110 volt or 220 volt plug; can be hardwired to a pressure switch to come on with a well pump.  Works with well water flow rates from 1 – 50 Gallons per Minute (GPM)

Output rating:  0.1 – 24 Gallons per Day (GPD).  Pressure rating:  Will inject into lines with up to 110 PSI. 

Click on this link to check for more information.

Additional features:  Degassing Valve is built in which makes this great for chlorination use.  System includes Chlorination Pump, 10 Gallon Solution Tank, Injection Check Valve, tubing and installation fittings.  25 & 35 Gallon tanks also available for additional cost. 

120 Gallon Tank120 Gallon Contact Tank 
The CT-120 tank is a durable easy-to-install retention tank designed to provide optimum contact time during chemical treatment. These lightweight seamless totally non-corrosive retention tanks are ideal for new and replacement installation where durability is at a premium. 100% non-metallic polymer materials. Impervious to chemical attack.  Comes with  1-1/4 inch inlet.

Click on this link to check for more information.

24” x 74”

Excellent Warranty:  5 Years from date of installation.

Vacuum BreakerVacuum Breaker, ½” mpt.   

Vacuum breaker relief valve Watts 1/2" male 200 PSI maximum.
Required for contact and retention tanks to prevent vacuum in system and avoid imploding vessel.

Click on this link to check for more information.

Carbon Filter 5700-E 1.5 CF 
Carbon Filter 5700e 1.5 CF
Includes 1.5 cubic feet of carbon filter media; and Digital 5700-E control valve.

All the filter media you need for the system is included. Excellent for use in de-chlorinating water, taking out hydrogen peroxide and removing many tastes and odors.
Much longer life and higher flow rates than carbon filter cartridges.

Click on this link to check for more information.

Excellent Warranty:  5 Years on Control Valve & 10 years on the media tank.

UV Treatment:

Wonderlight UV Sterilizer GN-15: 15 GPM  - NSF Certified

Wonderlight UV Sterilizer GN-15: 15 GPM
Kill bacteria and viruses without the use of chlorine or other chemicals! 15 gallons per minute maximum flow rate recommended.  Inlet and outlet is 1 inch NPT. Heavy-duty 304 stainless steel UV is suitable for water pressures up to 100 PSI.  Two end caps make it easy to access the lamp for changing from either end; not one end like some UV sterilizers. Convenient external ballast and power supply makes installation easy.

Dimensions: 3 inches diameter x 36 inches length.  Certified by the National Safety Foundation for reliability and performance.

UV lamp is rated for 9,000 hours which is approximately one year of continuous operation.

Click on this link to check for more information.