Quantification of Biofilm Formed at a Plan Liquid- Liquid Interface

This study describes an in situ technique allows measuring thickness of biofilm growing at liquid-liquid interface. Two probes (100μm) were used to measure the electrical conductance, the first probe penetrates the first liquid (hydrophobic liquid) then the upper surface of the formed biofilm and the later penetrates the second liquid (salt solution), then the lower surface of the biofilm. The hydrophobic liquid-biofilm and biofilm-salt solution interfaces can be identified from the change in conductance values between the three phases. Results of this work showed that rate of biofilm formation were 15μm/day for non-aerated system and 20μm/day for aerated system. The relation between biofilm thickness and its dry weight for aerated and non-aerated systems can be linearly correlated according to the following formulas: Th. = 0.462DW + 0.063 and Th. = 0.472DW+0.0429 respectively.