Removal of micropollutants and nutrients in household wastewater using organic and inorganic sorbents

The efficiency of five organic and five inorganic sorbents in removing 19 organic micropollutants (MPs), phosphorus, nitrogen, and dissolved organic carbon (DOC) was tested in a two-week column experiment using household wastewater spiked with pharmaceuticals ( n = 6), biocides/pesticides ( n = 4), organophosphates ( n = 3), a fragrance, a UV-stablizer, a food additive,a rubber additive, a plasticizer and a surfactant. Two types of granular activated carbon (GAC), two types of lignite, a pine bark product, and five mineral-based sorbents were tested. All the organic sorbents except pine bark achieved better removal efficiencies of DOC (on average, 70 ± 27%) and MPs (93 ± 11%) than the inorganic materials (DOC: 44 ± 7% and MPs: 66 ± 38%). However, the organic sorbents (i.e. GAC and xyloid lignite) removed less phosphorus (46 ± 18%), while sorbents with a high calcium or iron content (i.e. Polonite® and lignite) generally removed phosphorus more efficiently (93 ± 3%). Ammonium-nitrogen was well removed by sorbents with a pH between 7 and 9, with an average removal of 87%, whereas lignite (pH 4) showed the lowest removal efficiency (50%). Some MPs were well removed by all sorbents (≥97%) including biocides (hexachlorobenzene, triclosan and terbutryn), organophosphates (tributylphosphate, tris-(1,3-dichloro-2-propyl)phosphate and triphenylphosphate) and one fragrance (galaxolide). The pesticide 2,6-dichlorobenzamide and the pharmaceutical diclofenac were poorly removed by the pine bark and inorganic sorbents (on average, 4%), while organic sorbents achieved high removal of these chemicals (87%).