91    MANGANESE TREATMENT BY TWO NOVEL METHODS AT
ABANDONED COAL STRIP MINES IN NORTH
ALABAMA
John A. Gordon,Professor
Julia L. Burr, Graduate Student
Center for the Management, Utilization,
and Protection of Water Resources
Tennessee Technological University
Cookeville, Tennessee 38505
INTRODUCTION
Mined areas frequently have surface drainage in the form of seeps and springs which may contain
appreciable quantities of iron and manganese. When these seeps leave the mined property, they are
subject to the effluent limitations described in Table I. Manganese in these seeps must be lowered to
2.0 mg/L before the water leaves the property.
The owner/operator of a mining area or reclaimed mine site needs a manganese treatment system
that is low in initial cost, requires minimal maintenance, and can operate without electrical power for
an indefinite time into the future. This paper presents two possibilities for this application —
manganese oxidation by a packed column system and manganese removal by wetlands.
MANGANESE TREATMENT SYSTEMS
Manganese is fairly stable at neutral pH values (6 to 8) and not readily oxidized by solely chemical
means. Generally, treatment involves raising the pH to 8 to 11 so that manganese will oxidize and
precipitate. Nicholas and Foree2 discussed using lime and sodium hydroxide to remove manganese
from active mining waters. They found that the pH had to be raised to a range of 8.4 to 9.3 to reach
the EPA and OSM limits of 2 mg/L in the discharge.
Kleinmann et al} noted that manganese precipitated with excess alkalinity is easily resolubilized,
while that precipitated with stronger oxidizing agents is relatively stable. Useful oxidizing agents were
NaOCl and KMn04. This observation was confirmed by Boll and Deshinksy4, who reported that
potassium permanganate could be used to oxidize the dissolved manganese to an insoluble manganese
precipitate. This technique has long been used to treat potable waters. In Tennessee, some operators
use ammonia to raise pH values and reduce manganese from pond effluents. Nonetheless, chemical
treatment is expensive and more desirable methods are being sought to solve the manganese problem,
especially at abandoned strip mined areas.
Many recent publications on removing manganese by wetlands are available.5,*.7.8,9.io,ii, and 12
However, Kleinmann et al.'1 presented a workshop on wetlands construction for treatment of mine
water which showed that not all wetlands are effective in removing manganese and that some will
periodically discharge more manganese than is coming into the system. Therefore, while wetlands
have considerable promise, they are not the end-all solution to manganese problems. Better treatment
Table I.    Effluent Limitation of Iron, Manganese, Total Suspended Solids, and pH for Mining
and Reclaimed Land '
Parameter
Iron, total (mg/L)
Manganese, total (mg/L)
Total suspended solids (mg/L)
pH
Maximum
Average of Daily Values
Allowable
for 30 Consecutive
Concentration
Discharge Days
7.0
3.5
4.0
2.0
70.0
35.0
6.0-9.0
6.0-9.0
907