title: Phosphorus removal from wastewater by field-scale fortified filter beds during a one-year study.
abstract: Due to low availability of alternative technologies, rural communities are unable to comply with national wastewater discharge limits. This study tested the effectiveness of filter bed fortification with biochar on phosphorus removal. Water-tight down-flow beds of sand and gas concrete, constructed alongside a reference sand bed (all 0.8 m deep and 0.75 m(2) surface area), were topped with a 0.2 m biochar layer. Pre-treated domestic wastewater with mean concentrations of 6.4 mg/L [Formula: see text] and 142.6 NTU, was infiltrated at 4 cm/d hydraulic loading rate. Ultimately, the biochar-sand was relatively outstanding in turbidity reduction, achieving <5 NTU. The biochar-gas concrete exhibited superior performance in [Formula: see text] removal, trapping 32.3 g (40.2%), compared with 20.5 g (25.6%) and 15.5 g (19.3%) by biochar-sand and reference bed respectively. However, statistical analysis revealed a weak correlation between pH and biochar-gas concrete removal efficiency (r(2 )= 0.2). The relationship was stronger for biochar-sand [Formula: see text] (r(2 )= 0.5) than reference (r(2 )= 0.4) bed. Paired samples t-tests showed that incorporating biochar into the sand bed significantly (p = .04) improved its [Formula: see text] removal efficiency. In conclusion, sand bed fortification with biochar could be an important measure for improving P removal and wastewater clarification efficiency.
authors.affiliation: a Division of Land and Water Resources Engineering , KTH Royal Institute of Technology , Stockholm , Sweden.
authors.forename: Ezekiel
authors.initials: E
authors.lastname: Kholoma
authors.affiliation: a Division of Land and Water Resources Engineering , KTH Royal Institute of Technology , Stockholm , Sweden.
authors.forename: Gunno
authors.initials: G
authors.lastname: Renman
authors.affiliation: a Division of Land and Water Resources Engineering , KTH Royal Institute of Technology , Stockholm , Sweden.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Renman
mesh_terms: D002606:Charcoal / Q000737:chemistry*; D005374:Filtration; D010758:Phosphorus / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D002606:Charcoal; D010758:Phosphorus; D062065:Wastewater; D014874:Water Pollutants, Chemical; C540010:biochar
keywords: Biochar; fortified filter beds; gas concrete; phosphorus removal; wastewater treatment