What does high pH indicate in relation to the formation of TTHMs?

High pH levels in water are associated with increased formation of total trihalomethanes (TTHMs). TTHMs are byproducts that occur when chlorine, used as a disinfectant in water treatment, reacts with organic matter present in the water. When the pH is elevated, the rate of these chemical reactions can increase, leading to a higher concentration of TTHMs.

Specifically, the reaction that produces TTHMs is influenced by the availability of organic precursors and the chlorine concentration, both of which can be affected by pH levels. A higher pH can also reduce the efficacy of chlorine, necessitating higher dosages which can further elevate TTHM formation.

This understanding emphasizes the importance of monitoring pH levels in water treatment processes to manage and mitigate the production of harmful byproducts like TTHMs effectively.