title: Heavy metal fate in pilot-scale sludge drying reed beds under various design and operation conditions.
abstract: Thirteen pilot-scale sludge drying reed bed (SDRB) units have been constructed and operated under various settings. The beds included a cobbles lower layer, where perforated PVC aeration tubes were placed, and two gravel layers on top. The setup included planted beds with common reeds and control units. Three sludge loading rates (SLR) were examined: 30, 60 and 75 kg dm/m(2)/yr. Heavy metal (HM) accumulation in the residual sludge layer was negligible or low, and was found to increase with sludge layer depth. Plant uptake was low; the belowground biomass accumulated significantly more HMs compared to the aboveground biomass. Less than 16% of the influent HM left the bed through drainage. HM accumulation in the gravel layer was the major metal sink in the mass balance. On the whole, the HM content of the residual sludge was below the legal limits proposed by the EU for land application.
authors.affiliation: Laboratory of Ecological Engineering and Technology, Department of Environmental Engineering, School of Engineering, Democritus University of Thrace, 67100 Xanthi, Greece. astefan@env.duth.gr
authors.forename: Alexandros I
authors.initials: AI
authors.lastname: Stefanakis
authors.forename: Vassilios A
authors.initials: VA
authors.lastname: Tsihrintzis
mesh_terms: D000704:Analysis of Variance; D001673:Biodegradation, Environmental; D018533:Biomass; D002857:Chromium / Q000737:chemistry; D005160:Facility Design and Construction; D019083:Mediterranean Region; D019216:Metals, Heavy / Q000032:analysis*; D010865:Pilot Projects; D006109:Poaceae / Q000737:chemistry*; D016062:Porosity; D012722:Sewage / Q000032:analysis*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014887:Weather
chemical_list: D019216:Metals, Heavy; D012722:Sewage; D002857:Chromium