Oxidising and non-oxidising biocides are commonly used in an attempt t
o control biofouling in industrial water systems. Many of these progra
mmes, however, fail due to the incorrect selection and application of
these chemical compounds. Knowledge of the organisms to be eliminated
and system hydraulics are important operational parameters in ensuring
the successful application of chemical control programmes. A further
complicating factor is the build up of bacterial resistance to many of
these compounds. One way of limiting resistance is the alternation of
oxidising and non-oxidising biocides at the correct miminum inhibitor
y concentration and using these in combination with surface active com
pounds to dislodge any biofilm. A variety of surface monitoring techni
ques are in use in order to monitor the success of biofouling control
programmes. Unfortunately none of these techniques are ideal acid resu
lts have to be considered very carefully.