Our well water in Central Kerala was contaminated with Choliform, E-coli, Pseudomonas and Sulphate reducing anerobes. It was for the first time the contamination was noticed which could have been due to various reasons like contamination of sewage water running about 50 feet away or due to the presence of our well in a industrial area. It is only with the onset of monsoons that the intensity has increased. After searching through the net and speaking to various consultants i treated the source well water directly with Shock Chlorination.
I maintained a 100 ppm of chlorine in the well which subsided to 10 ppm after 24 hours and 2 ppm 48 hours. It was noticed later that most of contaminants disappeared and only with further inflows of water due to good monsoon showers the contaminants did appear but with less intensity. I have been treating the well further with 2-3 ppm chlorine and having been maintaining the same. The results are they are controlled but they do remain with very low intensity. Since i am involved in the water processing business it is of paramount importance to me to ensure clean and pathogen free water. All the chemical parameters have been observed are either below detectable limits or well below the BIS prescribed limits.
The questions that I have are:
1. Is chlorine the right method to use for disinfection in water.
2. What is the desired level of chlorine for treatment.
3. What is the minimum period of contact with chlorine that necessarily need to be maintained for pretreatment.
4. Is there an alternative for chlorine , if so how effective is it and how does one apply it.
5. i have tried hydrogen peroxide with silver but the result is very disappointing as the disinfection seems to be effected only on the surface and the bacteria still remained even at levels of 15 and 17 ppm. And I have also realised that hydrogen peroxide with silver is not advisable as they are harmful to the human body.
6. is Adding chlorine by dosing the best method or is there a better method. Kindly advise on what is the right steps to be taken to get pathogen free water at the pretreatment stage itself.
Korah Paul
korah_p@writeme.com