Chlorine demand of biofilms in water distribution systems

Fixed biomass (biofilms) chlorine demand, produced from 3 test waters, is studied by the means of two methods: directly on colonized plastic beads and indirectly on biomass extracted after sonication. The first method results show that a steady state of biomass formation can be reached after an incubation period depending on test water quality. At steady state biofilms chlorine demand increases linearly with BDOC of water and increases according to the ratio surface/volume. The second method results show that extracted biomass chlorine demand is related with protein concentration and heterotrophic plate counts level in the extracts.