Year of Publication

2008

Degree Name

Master of Science (MS)

Document Type

Thesis

College

Agriculture

Department

Plant and Soil Science

First Advisor

Dr. A.D. Karathanasis

Second Advisor

Dr. Christopher Barton

Abstract

The treatment of Mn and SO42- contaminated mine drainage via a sulfate reducing bioreactor is expected to result in near-permanent immobilization of significant amounts of Mn and a portion of the sulfates within the matrix. This study tested several different combinations of organic amendments and inorganic substrates in an attempt to optimize sulfate reducing conditions and Mn removal capacity. Five different organic carbon sources, including corn mash, wood mulch, biosolids, soybean oil, and sorghum syrup in combination with five different inorganic substrates, including creek sediment, marble and limestone chips, polished gravel, and sand were tested in batch experiments. Results indicate a widely Mn variant removal potential among the treatments, ranging from 35% for soybean oil to 97% for the mulch mixture, with respective Eh ranges of +60 mV and -320 mV. Sulfate removal ranged from less than 10% to 85%. The most favorable combinations were tested in small scale bioreactors under dynamic conditions. Greater than 90% of Mn and 70% of sulfate was removed over a 65 day test period. Results indicate Mn removal mechanisms include sulfide, oxide, and carbonate formation and simple sorption and SO42- removal mechanisms of sulfide gas evolution, gypsum and MnS precipitation, and anion sorption/cation bridging.

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