Berrien Elkhart Forest
Southern County, County, Lawn,
Parameter Illinois Michigan Indiana Michigan
Benzene (ppb) 11 20 10 17
Ethyl benzene (mg/L) 25 20 400 68
Methylene chloride (mg/L) 58 33 17 290
Toluene (ppb) 780 150 300 370
Note: BOD, biochemical oxygen demand; COD, chemical oxygen demand; TDS, total dissolved solids.
Source: Reed, S.C. et al., Natural Systems for Waste Management and Treatment, 2nd ed., McGraw-Hill, New York, 1995. With permission.
providing the desired treatment benefits. The major issues of concern are removal of iron and manganese and moderation of the liquid pH. The FWS wetland has been preferred for this service because of the greater potential for aerobic conditions in the system and because the precipitated iron and manganese could result in clogging of a SSF wetland bed. The acidic condition of mine drainage is often caused by oxidation of iron pyrite:
The ferrous iron produced by the previous reaction undergoes further oxidation in a wetland system:
Was this article helpful?