Disinfection of Groundwater Systems
Why groundwater disinfection is its own topic
A groundwater supply typically has low, stable turbidity and low organic content, which
makes disinfection efficient and predictable - chlorine demand is low and a residual is easy to
hold. But the same water often carries iron, manganese, hydrogen sulfide and ammonia, each
of which consumes chlorine or converts it to a less effective form, and it may carry hardness
that scales the injection point. So the chemistry is simple and the practical problems are
specific.
Chlorine chemistry, briefly
Chlorine added to water forms hypochlorous acid, which is the effective disinfecting species,
in equilibrium with the hypochlorite ion, which is much weaker. The balance is set by pH:
- Lower pH favours hypochlorous acid, so disinfection is more effective.
- Higher pH favours hy