Development of a simulation for an anaerobic multi-compartment reactor for domestic wastewater treatment

Abstract

Domestic wastewater contains resources such as water, nutrients and energy-rich organics. The current wastewater treatment paradigm, however, consumes resources, rather than recovering them. Multiple-compartment anaerobic bioreactors, such as the anaerobic baffled reactor (ABR), are useful treatment systems for the implementation of the anaerobic microbial processes of hydrolysis, acidogenesis, acetogenesis and methanogenesis in treating domestic wastewater. The simple designs allow for methane generation with little or no energy input, while simultaneously reducing volumes of waste sludge relative to that generated in conventional energy-intensive aerobic treatment practices. Prior to the adoption of anaerobic systems as mainstream wastewater treatment processes, further research and development of nutrient and energy recovery are necessary, including the comparison to conventional wastewater treatment technologies. The use of modeling and computer simulation for treatment performance and resource recovery predictions would make anaerobic treatment technologies more accessible and provide a better understanding of the processes involved. In an effort to promote the widespread use of anaerobic systems as sustainable treatment options, the research aim was to assess the feasibility of using a computer simulation tool common to industry practice to model the effectiveness of wastewater treatment and methane generation of a pilot-scale multi-compartment ABR. Data from a multi-year study of an ABR in Golden, CO, were utilized for simulation, calibration and validation. The key finding was that creation, calibration and validation of a BioWin simulation modeling the ABR was possible. The simulation was able to predict concentrations of chemical oxygen demand (COD) removal performance and methane generation within 10 percent. The overall success of the simulation required appropriate characterization of the influent wastewater, use of median concentrations from the data set and limited use of methane in determining COD concentrations. Employment of this simulation will help with understanding the complex processes involved in anaerobic treatment, simplify reactor development and make anaerobic treatment more accessible.