Hi,
I know about chlorine reaction in waste water. Its like chlorine reacts with water to form hypochlorous acid.
H2O + Cl2 ----> HOCl + HCl
This HOCl helps in desinfection / oxidation of impurities. It destroys algae, minerals, dust & material causing odour, colour, turbidity etc..
... Sorry, I am not much aware of methane reaction.
