title: Development of biomass in a drinking water granular active carbon (GAC) filter.
abstract: Indigenous bacteria are essential for the performance of drinking water biofilters, yet this biological component remains poorly characterized. In the present study we followed biofilm formation and development in a granular activated carbon (GAC) filter on pilot-scale during the first six months of operation. GAC particles were sampled from four different depths (10, 45, 80 and 115 cm) and attached biomass was measured with adenosine tri-phosphate (ATP) analysis. The attached biomass accumulated rapidly on the GAC particles throughout all levels in the filter during the first 90 days of operation and maintained a steady state afterward. Vertical gradients of biomass density and growth rates were observed during start-up and also in steady state. During steady state, biomass concentrations ranged between 0.8-1.83 x 10(-6) g ATP/g GAC in the filter, and 22% of the influent dissolved organic carbon (DOC) was removed. Concomitant biomass production was about 1.8 × 10(12) cells/m(2)h, which represents a yield of 1.26 × 10(6) cells/μg. The bacteria assimilated only about 3% of the removed carbon as biomass. At one point during the operational period, a natural 5-fold increase in the influent phytoplankton concentration occurred. As a result, influent assimilable organic carbon concentrations increased and suspended bacteria in the filter effluent increased 3-fold as the direct consequence of increased growth in the biofilter. This study shows that the combination of different analytical methods allows detailed quantification of the microbiological activity in drinking water biofilters.
authors: Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Duebendorf, Switzerland.
authors: Silvana
authors: S
authors: Velten
authors: Markus
authors: M
authors: Boller
authors: Oliver
authors: O
authors: Köster
authors: Jakob
authors: J
authors: Helbing
authors: Hans-Ulrich
authors: HU
authors: Weilenmann
authors: Frederik
authors: F
authors: Hammes
mesh_terms: D018441:Biofilms / Q000254:growth & development; D018533:Biomass; D002244:Carbon / Q000032:analysis; D002606:Charcoal / Q000737:chemistry*; D060766:Drinking Water / Q000382:microbiology*; D005374:Filtration / Q000295:instrumentation*; D007700:Kinetics; D009391:Nephelometry and Turbidimetry; D009930:Organic Chemicals / Q000032:analysis; D010710:Phosphates / Q000032:analysis; D010839:Phytoplankton / Q000254:growth & development; D010865:Pilot Projects; D014865:Waste Disposal, Fluid; D018508:Water Purification / Q000295:instrumentation*; D060753:Water Quality
chemical_list: D060766:Drinking Water; D009930:Organic Chemicals; D010710:Phosphates; D002606:Charcoal; D002244:Carbon