Tier 2 utilizes a substituted phenol
chemical probe (vanillin) to react with the
bromamines. This indirectly measures its
concentration. It produces bromovanillin,
which is stable and easily measurable by
LC-MS/MS. A novel LC-MS/MS method,
employing vanillin, will measure the
concentration of bromovanillin in order
to understand which factors play a role
in bromamine formation and chloramine
(initial bromide concentration, chloramine
dose, NOM concentration, Cl :N, order of
chemical addition, pH, and temperature).
Tier 3 constructs a comprehensive mass
balance of bromine-containing species in
different waters following chloramination.
The chemical probe method will measure
the concentrations of all bromamines. An
equilibrium model will help determine
the relative speciation of mono-, di-, and
tribromamine from the total concentration.
Brominated trihalomethanes (THMs),
HAAs, and concentrations of TOBr will
also be measured.
Future Work on Minimizing
More work is warranted on the relationship
between bromamines and chloramine
demand and decay during chloramination.
This project may develop a strategy to
minimize bromamine formation. This
would, in turn, optimize the chloramine
process possibly through blending,
contact time, or sequence of chemical
addition. Understanding the conditions
of bromamine formation may allow utilities
to better manage how desalinated water is
blended into the distribution system.
The required dosages of ammonia and
chlorine are yet to be determined in order
to optimize bromamine formation during
ozonation. Optimal bromamine formation
minimizes the formation of bromate during
ozonation. Optimizing this technique
will benefit utilities using ozone across
the country requiring a bromate control
technique to meet the disinfection objectives
established in the Long Term 2 Enhanced
Surface Water Treatment Rule (LT2ESWTR).
The final project report is expected to be
published in 2010. For more information
about the study, contact Djanette Khiari