A　pilot-scale　bio-filter　was　constructed　for　the　removal　of　high　concentrations　of　iron　(TFe　9.0-12.0　mg·L-1,　Fe(II)　6.5-8.0　mg·L-1),　manganese　(1.9-2.1　mg·L-1),　and　ammonia　nitrogen　(1.4-1.7　mg·L-1)　simultaneously　from　low　temperature　(5-6)　groundwater　in　a　plant.　The　results　showed　that　iron　was　removed　at　the　beginning　of　the　bio-filter　start-up,　and　manganese　and　ammonia　nitrogen　were　removed　on　day　72　and　day　75,　respectively.　The　start-up　period　was　influenced　by　the　culture　temperature　and　the　raw　water　quality.　For　higher　filtration　rates,　the　removal　of　manganese　was　lower.　When　the　filtration　rate　was　more　than　1.0　m·h-1,　the　maximum　removal　of　manganese　was　about　3.0　mg·L-1.　Manganese　was　the　limiting　factor　for　the　increase　of　filtration　rate,　and　the　maximum　filtration　rate　of　the　single　bio-filter　was　4.5　m·h-1.　When　the　filtration　rate　was　less　than　6.0　m·h-1,　the　removal　of　ammonia　nitrogen　was　about　1.5　mg·L-1,　which　was　not　affected　by　the　filtration　rate.　Dissolved　oxygen　(DO)　deficiency　led　to　failure　with　the　removal　of　more　ammonia　nitrogen.　The　required　thickness　of　the　bio-filter　required　for　purification　increased　as　the　concentration　of　manganese　and　ammonia　nitrogen　increased　when　DO　was　sufficient.　The　removed　iron,　manganese,　and　ammonia　nitrogen　move　to　the　depth　of　the　filter　layer,　and　there　will　be　＇manganese　dissolution＇　when　the　filtration　rate　is　increased.　Iron　and　ammonia　nitrogen　in　the　filter　layer　can　be　oxidized　and　removed　simultaneously.　Manganese　is　oxidized　and　removed　after　the　iron　and　ammonia　nitrogen.　The　effective　oxidation　and　removal　section　of　manganese,　iron,　and　ammonia　nitrogen　are　obviously　graded.　©　2017,　Science　Press.　All　right　reserved.