Use of natural materials for the inhibition of iron oxidizing bacteria involved in the generation of acid mine drainage

Phosphorus removal performance of acid mine drainage from wastewater

“…Both dissociation of H 2 PO 4 − to release PO 4 3− and affinity of Fe 2+ , Fe 3+ and Al 3+ toward PO 4 3− and OH − were depended on pH. With increasing pH, P removal of AMD and FeSO 4 increased quickly as shown in Fig.…”

“…Increasing pH will bring about equilibriums of equations of (4)-(6), (10) and (11) moving to the right directly, thus concentrations of Fe 2+ , Fe 3+ and Al 3+ will decrease and concentration of PO 4 3− will increase. The decrease of concentration of Fe 3+ and Al 3+ is a little more than the increase of concentration of PO 4 3− , but the decrease of concentration of Fe 2+ is much smaller than the increase of concentration of PO 4 3− . Thus the equilibrium of equation of (7) moves to the right quite a lot and the equilibriums of equations of (8) and (9) will decrease a lot and the equilibrium concentrations of equations of (8) and (9) will increase a little.…”

“…(4)-(9) move to the right, more PO 4 3− and OH − were precipitated, thus the pH of the effluent decreased and then P removal increased. When the concentration of PO 4 3− was very low, further increasing dosage of Fe 2+ , Fe 3+ and Al 3+ resulted in little increasing P removal and much more OH − precipitated. So the effects of dosage of AMD, FS, PFS and FeSO 4 on TP removal, residual TFe present as Fig.…”

“…Pyrite is one of the most common sulfide minerals in the earth, and exists not only in the form of ore resource but also as gangue in most metal sulfides and coal deposits. Therefore AMD is very common and one of the worst environmental problems across the globe [4,5].…”

“…Usually the generation of AMD is described by pyrite oxidation which is illustrated by the following equations [9]: 2FeS 2 + 2H 2 O + 7O 2 = 2Fe 2+ + 4SO 4 2− + 4H + (1)…”