Non-oxidizing biocides are widely used in industrial water treatment system and are typically formulated
as liquid products. Several solid biocide formulations of non-oxidizers are also formulated as solids,
including DBNPA (dibromonitrilopropionamide) and bronopol (bromonitropropanediol). Recently, a
novel solid formulation of chloromethyl-methylisothiazolone (CMIT/MIT) biocide has been developed
for microbial control in small to medium sized cooling water systems. CMIT/MIT is well recognized for
its excellent broad spectrum activity versus various types of bacteria, (including Legionella, biofilmformers
and sulfate-reducers), algae and fungi. This new isothiazolone solid tablet dissolves rapidly and
has improved safety and handling features versus liquid formulations. The tablet is completely water
soluble, leaves no residue, has good compatibility with standard materials of construction, and is
wrapped in a protective water soluble outer film. This paper will describe the physical-chemical
characteristics of the new solid isothiazolone biocide, provide results of lab studies, and review other
non-oxidizing biocide solid formulations currently in use today.
Keywords: water treatment, biocide, non-oxidizer, solid, isothiazolone, dibromonitrilopropionamide,
DBNPA, bronopol, bromonitropropanediol