title: Efficacy of reactive mineral-based sorbents for phosphate, bacteria, nitrogen and TOC removal--column experiment in recirculation batch mode.
abstract: Two mineral-based materials (Polonite and Sorbulite) intended for filter wells in on-site wastewater treatment were compared in terms of removal of phosphate (PO4-P), total inorganic nitrogen (TIN), total organic carbon (TOC) and faecal indicator bacteria (Escherichia coli and Enterococci). Using an innovative, recirculating system, septic tank effluent was pumped at a hydraulic loading rate of 3000 L m(2) d(-1) into triplicate bench-scale columns of each material over a 90-day period. The results showed that Polonite performed better with respect to removal of PO4-P, retaining on average 80% compared with 75% in Sorbulite. This difference was attributed to higher CaO content in Polonite and its faster dissolution. Polonite also performed better in terms of removal of bacteria because of its higher pH value. The total average reduction in E. coli was 60% in Polonite and 45% in Sorbulite, while for Enterococci the corresponding value was 56% in Polonite and 34% in Sorbulite. Sorbulite removed TIN more effectively, with a removal rate of 23%, while Polonite removed 11% of TIN, as well as TOC. Organic matter (measured as TOC) was accumulated in the filter materials but was also released periodically. The results showed that Sorbulite could meet the demand in removing phosphate and nitrogen with reduced microbial release from the wastewater treatment process.
authors.affiliation: Department of Land and Water Resources Engineering, Royal Institute of Technology, Teknikringen 76, SE-100 44 Stockholm, Sweden. chanils@kth.se
authors.forename: Charlotte
authors.initials: C
authors.lastname: Nilsson
authors.forename: Ramnath
authors.initials: R
authors.lastname: Lakshmanan
authors.forename: Gunno
authors.initials: G
authors.lastname: Renman
authors.forename: Gunaratna Kuttuva
authors.initials: GK
authors.lastname: Rajarao
mesh_terms: D016983:Enterococcus / Q000302:isolation & purification; D004926:Escherichia coli / Q000302:isolation & purification; D005374:Filtration / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen / Q000737:chemistry / Q000302:isolation & purification*; D010087:Oxides / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry / Q000302:isolation & purification*; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods*
chemical_list: D010087:Oxides; D010710:Phosphates; C507562:Polonite; D009584:Nitrogen
keywords: Enterococci; Escherichia coli; Polonite; Sorbulite