Experiment results of removing heavy metals in the field HMs Wellwater As Pb Cd Cr (1) (2) (1) (2) (1) (2) (1) (2) 1st well 0.40 <0.01 0.03 <0.01 0.12 <0.003 0.25 <0.003 2nd well 0.11 <0.01 0.42 <0.01 0.15 <0.003 0.82 <0.003 3rd well 0.45 <0.01 0.32 <0.01 0.12 <0.003 0.85 <0.003 4th well 0.13 <0.01 0.18 <0.01 0.10 <0.003 0.62 <0.003 QCVN 01: 2009/BYT ≤ 0, 01 ≤ 0, 01 ≤ 0, 003 ≤ 0, 05 Effective Index 96, 33 95, 79 97, 55 99, 53 (1): Before filtration; (2): After filtration The concentration of HMs in all four experimented wells met the National permissible standard QCVN 01: 2009/MOH, the filtration efficiency ranged from 95 - 99%, highest in Cr and lowest in Pb, in order of Cr> Cd> As> Pb.