title: How to dose powdered activated carbon in deep bed filtration for efficient micropollutant removal.
abstract: Direct addition of powdered activated carbon (PAC) to the inlet of a deep bed filter represents an energy- and space-saving option to remove organic micropollutants (OMPs) during advanced wastewater treatment or drinking water purification. In this lab-scale study, continuous dosing, preconditioning a filter with PAC and combinations thereof were investigated as possible dosing modes with respect to OMP adsorption efficiency. Continuous dosing resulted in decreasing effluent concentrations with increasing filter runtime due to adsorption onto accumulating PAC in the filter bed. Approximately constant removal levels were achieved at longer filter runtimes, which were mainly determined by the dose of fresh PAC, rather than the total PAC amount embedded. The highest effluent concentrations were observed during the initial filtration stage. Meanwhile, preconditioning led to complete OMP adsorption at the beginning of filtration and subsequent gradual OMP breakthrough. PAC distribution in the pumice filter was determined by the loss on ignition of PAC and pumice and was shown to be relevant for adsorption efficiency. Preconditioning with turbulent upflow led to a homogenous PAC distribution and improved OMP adsorption significantly. Combining partial preconditioning and continuous dosing led to low initial effluent concentrations, but ultimately achieved concentrations similar to filter runs without preconditioning. Furthermore, a dosing stop prior to the end of filtration was suitable to increase PAC efficiency without affecting overall OMP removals.
authors.affiliation: Technische Universität Berlin, Chair of Water Quality Control, Str. des 17. Juni 135, 10623 Berlin, Germany. Electronic address: johannes.altmann@tu-berlin.de.
authors.forename: Johannes
authors.initials: J
authors.lastname: Altmann
authors.affiliation: Technische Universität Berlin, Chair of Water Quality Control, Str. des 17. Juni 135, 10623 Berlin, Germany.
authors.forename: Aki S
authors.initials: AS
authors.lastname: Ruhl
authors.affiliation: Technische Universität Berlin, Chair of Water Quality Control, Str. des 17. Juni 135, 10623 Berlin, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Sauter
authors.affiliation: Technische Universität Berlin, Chair of Water Quality Control, Str. des 17. Juni 135, 10623 Berlin, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Pohl
authors.affiliation: Technische Universität Berlin, Chair of Water Quality Control, Str. des 17. Juni 135, 10623 Berlin, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Jekel
mesh_terms: D000327:Adsorption; D002606:Charcoal / Q000737:chemistry*; D005374:Filtration / Q000295:instrumentation / Q000379:methods*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; D002606:Charcoal
keywords: Adsorption; Advanced wastewater treatment; Dosing optimization; Organic micropollutant; Powdered activated carbon; Rapid filtration