The monitoring of biofouling is continuously evolving with new and bet
ter techniques being developed all the time. The major drawback of the
currently used techniques is that these methods are complicated and t
ime-consuming, involving culturing and counting of attached organisms.
A continuously circulating batch culture system was therefore designe
d to study biofouling spectrophotometrically. Absorbance of bacteria a
ttached to a glass tube was compared with direct counts done on DAPI-s
tained bacteria attached to 3CR12 coupons. Direct measurements of abso
rbance correlated well with the total counts obtained using the DAPI t
echnique (r(2) = 0.925). Spectrophotometry proved to be an easy, inexp
ensive and reliable alternative to techniques requiring laborious coun
ting of microorganisms, for example the DAPI technique, for quantifica
tion of biofouling. Copyright (C) 1996 IAWQ.