A comprehensive assessment on commercially available standard anion resins for tertiary treatment of municipal wastewater

Three commercially available standard anion resins (ARs) produced quality sulfate-free reclaimed water containing low levels of phosphorus (P) (∼0.10 mg L−1), nitrate (∼0.20 mg L−1) and dissolved organic matters (DOMs) (∼0.68 mg L−1) from the actual secondary effluent of anaerobic/anoxic/aerobic process for municipal wastewater (MW-SE, containing 67 mg sulfate L−1, 1.30 mg P L−1, 8.50 mg nitrate L−1 and 3.30 mg DOMs L−1) in the fixed-bed column experiments. The influent DOM levels (1.2–9.4 mg L−1) had minor influences on nutrient removal performance. The stable adsorption efficiencies of ≥89, ≥95 and ≥71% and elution efficiencies of ≥99, ≥92 and ≥54% were achieved for phosphate, nitrate and DOMs in 5 successive adsorption–regeneration cycles. The standard ARs should be combined with the anoxic/aerobic biodenitrification process to better recover P resources from MW and achieve the highest nitrogen and P removal. With chloride salt fertilizers (e.g. NH4Cl or KCl) as regenerants, most of the P and nitrate in MW-SE can be concentrated into spent regenerant that can be easily and fully converted to a new nitrogen phosphorus mixed fertilizer, which will finally solve the disposal problem of spent brines.