(393d) Modeling and Analysis of Anaerobic Membrane Bioreactor (AnMBR) for Integrated Resource Recovery from Wastewater

Concepts such as the Water-Energy Nexus and Circular Economy are becoming increasingly important in global resource management. To achieve these goals integrated resource recovery from wastewater is a high priority. Anaerobic Membrane Bioreactor (AnMBR) is an emerging technology that allows for the digestion of waste and capture the products of digestion including energy, nutrients, and highly value-added chemicals. AnMBRs require the use of costly membranes that need to be regularly replaced, and the costs of membrane cleaning and replacement may limit the industrial application of this technology. Captured products of digestion may allow for the recuperation of operating costs and allow AnMBR to be an economically viable alternative to traditional wastewater treatment techniques. To evaluate the viability of AnMBR technology a detailed process model must be developed. Additionally, due to the variability in microbiological communities and membrane fouling dynamics of AnMBR systems, results of AnMBR treatment must be evaluated for specific waste streams.

We present a robust process model based on the ADM1 model for the treatment of swine wastewater in an AnMBR system. Updates to the ADM1 model have been included to incorporate membrane fouling dynamics and potential inhibition of methanogenesis through the consumption of acetate. The process model has been developed so that optimization of operating conditions can be conducted at steady-state equilibrium conditions of the digester. Specifically optimization using mixed integer nonlinear programing (MINLP) is conducted in Pyomo using the IPOPT algorithm. Sensitivity analyses show the importance of membrane fouling, solids retention time, and initial concentration of carbohydrates, lipids, and proteins in the waste stream. The implications of the findings for recovering resources from animal wastewater streams will be discussed along with discussion of future studies.