Chlorine injection guidelines
asked 1 June 2016 asked by yann (360 points)
Hi I don't have any info on the regulatory side, but as a technical argument, chlorine has a significant corrosive impact on boring casings, pumps, risers, etc.; and it can jeopardize the longevity of the installation itself. For the past 2 - 3 years, I have repeatedly performed camera inspections and most of my boreholes have been chlorinated—the pics speak for themselves. -In terms of analytics, it allows for more "representative" raw water samples. As far as re-injecting the network, in our area we have to advise the local health authorities so they can test for THMs downstream. Regards,
Hi, As far as I know, there is no regulation regarding injection procedures for chlorine in a network. For THMs, it's 100 micrograms/L max. You can tell your client that the injection of chlorine in a borehole is not mandatory. If chlorination is used, there is a strong likelihood of THMs developing in the drinking water. If you use a filter after your well followed by chlorination, it is not necessary to repeat the chlorination, since you know that the water between the well and the plant will not be consumed by anyone. The THMS are dangerous to your health, so it is important to prevent them from forming. As explained above, the more chlorine, the higher the rates of THM, and this must not exceed accepted levels. I hope that answers your question.
Most water authorities don't allow pre-chlorination because of the THM problem. When chlorine interacts with organic matter in the water, the disinfection creates this toxic by-product. Not to mention degrading equipment as mentioned previously.