Predicting the Onset of Metal Leaching from Land Application of Wastewater Using Soil Sensors and Microbial Community Analyses

Abstract

Several food processors use land application to treat process wastewater. Excessive organic and hydraulic loadings can result in environmental harm through surface water runoff and groundwater contamination. A recently recognized impact is the mobilization of heavy metals from the soil. The metals serve as the electron acceptors when oxygen is depleted and anaerobic microorganisms predominate. The objective of this research is to determine the feasibility of using moisture and oxygen sensors to predict changes in the soil environment resulting from the addition of wastewater that leads to anaerobic conditions. Eight 46-cm diameter, 0.97-m tall columns were constructed, filled with clean sand, and instrumented with sensors at three depths. Three organic loadings were tested: 7-, 56-, and