The validation of stormwater biofilters for micropollutant removal using in situ challenge tests

•This study attempts for the first time to validate biofilters for stormwater harvesting.•TPHs, glyphosate, DBP, DEHP, pyrene and naphthalene were well removed (>80%).•Atrazine and simazine were poorly removed under challenge conditions (80% for total petroleum hydrocarbons (TPHs), glyphosate, dibutyl phthalate (DBP), bis-(2-ethylhexyl) phthalate (DEHP), pyrene and naphthalene loads by both configurations under the most challenge conditions; the removal of pentachlorophenol (PCP) and phenol loads was >80% in LS-noSZ and 50–80% in S-SZ, while chloroform had load removal rates between 20% and 50%. Biofilters were less effective in removing atrazine and simazine with load removal 20–50% in LS-noSZ and