The　effluent　manganese　(Mn)　and　ammonia　nitrogen　(NH3-N)　concentration　were　found　excessive　when　the　low-temperature　(5-7.8)　groundwater　containing　high　NH3-N,　iron　(Fe)　and　Mn　contents　(NH3-N＞3.0　mg/L,　Total　Fe＞12　mg/L,　Fe2+＞8.0　mg/L,　Mn2+＞3.0　mg/L)　was　purified　by　＇one-stage　aeration　combined　with　one-stage　filtration＇　process.　To　improve　the　purification　efficiency,　the　start-up　of　＇two-stage　aeration　combined　with　two-stage　filtration＇　purification　process　and　the　oxidation-removal　active　sites　(ORAS)　of　Fe,　Mn　and　NH3-N　were　investigated.　Two-stage　bio-purification　process　successfully　started　after　133　days　and　the　start-up　period　was　mainly　related　to　the　Mn　content.　The　results　showed　that　the　removal　capacity　of　NH3-N　and　Mn　was　29.66　g/(m2·h)　and　27.08　g/(m2·h)　respectively,　and　the　water　yield　was　a　double　of　one-stage　bio-purification　process.　According　to　the　ORAS,　Fe　was　removed　to　trace　levels　in　the　0-50　cm　section　of　the　primary　filter　column,　and　the　NH3-N　was　removed　by　55.23%　and　44.10%　respectively　in　the　0-135　cm　segment　of　the　primary　filter　column　and　0-50　cm　segment　of　the　secondary　filter　column.　There　were　significant　removal　classification　between　Mn　and　NH3-N　during　the　oxidation-removal　process.　The　activity　of　Mn-oxidizing　bacteria　(MnOB)　was　significantly　inhibited　by　NH3-N　in　concentration　greater　than　2.25　mg/L.　The　removal　ratio　and　ORAS　of　Mn　in　both　filter　columns　were　affected　by　the　concentration　of　NH3-N　in　raw　water　as　well　as　the　filtration　rate.　After　a　successful　start-up,　the　Mn　was　removed　by　5.53%　and　89.34%　respectively　in　the　primary　and　secondary　filter　columns.　©　2018,　Editorial　Board　of　Journal　of　Harbin　Institute　of　Technology.　All　right　reserved.