Simulation of natural attenuation with multiple electron acceptors

Natural attenuation has recently emerged as a potential remedial alternative at contaminated sites. Groundwater transport and fate models are generally used to assess the viability of using natural attenuation at a site. These models have traditionally focused on modeling advection, dispersion, and sorption--three of the main attenuation mechanisms in groundwater. A fourth key variable that impacts natural attenuation is biodegradation. The BIOPLUME II model is one of the few public domain models that simulate aerobic biodegradation in groundwater. This paper describes a major enhancement to the model, referred to as BIOPLUME III. The enhanced model simulates aerobic and anaerobic processes due to the presence of multiple electron acceptors: oxygen, nitrate, iron, sulfate, and carbon dioxide. The BIOPLUME III model simulates sequential biodegradation processes depending on the availability of electron acceptors in the aquifer.