Neutralization in anaerobic treatment of an acidic waste

Abstract Anaerobic treatment requires maintenance of a stable pH near the neutral range. In evaluating treatment of an acidic waste from chemical pulping, neutralization costs were identified as an important factor. Conceptual and mathematical models of the anaerobic process were formulated incorporating bacterial transformations and chemical equilibria. Simulations were used to compare the effects of several sodium bases, to assess the role of SO 2 and H 2 S in controlling the neutralization requirements, and to evaluate effluent recycle as a tool for increasing influent pH. Gas stripping to reduce CO 2 in the recycle was also evaluated. This modeling approach can be applied to other industrial wastes that may be treated anaerobically and can be an important tool in assessing feasibility of treatment of acidic wastes.