Drinking Water Chlorine Disinfectant System 2

[UTChemE]

I need help in setting up a drinking water disinfection system for the company that I work with. This is new to me and I do not know where to start. The population served is around 25-35 people with a low to moderate water well flowrate. This will help us meet TCEQ regulations.

 

[bimr]

What specific help do you need? As a first step, you probably need to review the regulations.

 

[UTChemE]

Bimr

I need to have residual chlorine at .2mg/l and over a four sample average between .2 - 4. mg/l residual chlorine. I've been told that I can use gas, tablets or liquid bleach. I just need the simplest configuration to dose chlorine in the water line going into my two small storage tanks. Thanks in advance for your help.

 

[CAGmuer]

Where are you located? For example, in Florida, you would go to the FDEP website to permit the water treatment system. The application forms list several Best Practices.

Christopher Gmuer, EI
CAUSSEAUX, HEWETT, & WALPOLE, INC.
Gainesville, Florida
ENGINEERS - SURVEYORS - PLANNERS

http://www.chw-inc.com

 

[UTChemE]

I am located in Texas. The TCEQ has their regulations and specs, but no specific recommendations for system construction are given. The last time that I spoke to the state they told me something as simple as a 55 gal. drum of bleach with a dosing pump would suffice. I am just attempting to see if anybody on this forum has experience with disinfection. Thanks for your assistance.

 

[bimr]

There is a lot of information online for you to assist you:

http://www.mi-water.org/miawwa/committees/Water_Treatment/Sodium Hypochlorite and Chlorine Gas.pdf

http://www.cityofyamhill.com/Images/photos/hypo.htm

http://www.forceflow.com/news/monitor_hypofeed.html

http://www.wrights-trainingsite.com/Sodiumhypoonb.html

http://www.tppump.com/media/literat... Flo-Pak liquid chlorination systems data.pdf

http://www.lmipumps.com/corp/details/0,,CLI1_DIV12_ETI3738,00.html

http://www.h2ocontrols.net/PHP/images/file/LCV_Spec.pdf

http://www.chemfeedtech.com/liquid_chlorination.html

 

[SteveWag]

If your source is a simple well/pump setup, then a 15-gallon shipping container of 12% “bleach” and a dosing pump may suffice. Some states will not allow feeding from a shipping drum, but it is easier on the operator than transferring the stuff to a day tank. Try to feed the bleach neat, that is, without dilution. Figure 1 gallon of 12% bleach equals 1 pound of elemental chlorine. Do the math to determine dosing rate. You need to know the well flow rate or be in the ball park, in order to size the dosing pump. For low/variable rates (I try to always do this) install a flow meter and use it to pace the dosing pump. This is not as expensive as it sounds. This meter provides a pulsed output related to flow:

http://jerman.com/dljcmeters.html

Looking at the chart, a meter can be found giving 1 contact per gallon or per 10 gallons. If this contact is used to pace a dosing pump, varying flow rates from the source can be tolerated.

These pumps can provide 1 stroke for every pulse or 1 stroke for every 64 pulses or anything in between. Calculate the volume per stroke by dividing FEED/HOUR by strokes/min and then by 60 (min to hour):

http://www.prominent.us/desktopdefault.aspx/tabid-9804/1029_read-179/

The last thing is to specify a “de-gassing head”. This will return a VERY small bit of flow to the supply tank at each stroke. Because the discharge is at the top, any gas will collect there and be returned to the supply tank. This will prevent gas from building up and causing pumping problems.

You will need to double check my numbers, but 0.01 ml/Gallon (of 12% sodium hypochlorite) will result in 0.3 mg/L chlorine residual, maybe?

Steve

 

[jawhite]

I would suggest some type of flow paced peristaltic pump similar to the one shown on this page:

http://www.blue-white.com/artChloramine.htm

You'll also need a way to constantly monitor chlorine levels. Something like this Hach unit:

http://www.hach.com/hc/search.product.details.invoker/PackagingCode=5440001/