To　study　the　effects　of　di　(2-ethylhexyl)　phthalate　(DEHP)　on　nitrification　and　its　removal,　two　biological　aerated　filters　were　operated　in　parallel　for　60　days.　One　filter＇s　influent　was　with　100　μg/L　DEHP　while　the　other＇s　was　not.　The　two　filters　were　run　with　the　same　ammonia　loadings　of　0.6　and　1.5　kg　NH4+-N/(m3·d)　successively.　All　results　showed　that,　nitrite　accumulation　ratio　in　effluent　reached　83.92%　and　80.71%,　and　ammonia　nitrogen　removal　efficiency　reached　97.52%　and　49.39%　respectively　under　the　two　ammonia　loadings　for　the　filter　fed　with　100　μg/L　DEHP.　For　the　filter　without　DEHP　adding,　nitrite　accumulation　ratio　in　effluent　were　64.15%　and　49.37%,　and　the　ammonia　nitrogen　removal　efficiency　were　98.77%　and　49.34%　respectively.　DEHP　in　influent　accelerates　the　nitrite　accumulation　but　has　no　negative　effects　on　ammonia　removal.　For　the　filter　with　DEHP　in　influent　under　the　ammonia　loading　of　0.6　kg　NH4+-N/(m3·d),　percent　of　ammonia　removal　increased　gradually　along　the　flow　direction　and　reached　98.40%　at　the　filter　bed　depth　of　1　400　mm.　Nitrite　accumulation　ratio　increased　gradually　and　then　decreased　along　the　flow　direction　with　the　maximum　accumulation　ratio　of　94.21%　reached　at　the　filter　bed　depth　of　800　mm.　The　DEHP　average　removal　efficiencies　were　91.71%　and　89.38%　respectively　under　the　two　ammonia　loadings.　Most　DEHP　removal　occurred　in　the　initial　200　mm　filter　bed.　©　2015,　Science　Press.　All　right　reserved.