Bacterial Utilization of Simple Alcohols and Their Influence on Saturated Hydraulic Conductivity

Abstract

AbstractTwo simple alcohols (methanol and n‐propanol) were used to leach saturated soil columns for 2,000 hours, and changes in saturated hydraulic conductivity (Ksat) over time were determined. For both alcohols and a distilled water treatment, Ksat was found to decrease with time, attaining a constant value after approximately 1,500 hours. The addition of simple alcohols reduced Ksat considerably when compared with the flow rate of distilled water in soils. Initial decreases in Ksat were attributed to structural breakdown of unstable aggregates and expansion of clays, but the final portion of conductivity‐time curves was probably due to microbial action, in which soil pores became clogged with products of growth and cells. The pH values of effluents collected from soils treated with simple alcohols were lower than those of the added influents. Soils leached with distilled water became more acidic than those leached with methanol and n‐propanol. Phosphatase activity was assayed in each soil column, and results showed greater activities in the oxidized zones of soils. The magnitude of phosphatase activities in the oxidized zones of the treated soils were consistently higher in the following order: methanol > n‐propanol > distilled water. The decrease in Ksat of soils treated with simple alcohols was related to acid phosphatase activity, in that, as phosphatase activity increased, Ksat decreased.