The Role of Process Modeling in designing odor mitigation solutions: Developing Emissions Ratings for Process Technologies and Structures using Toxchem™

Process models are used extensively for compliance reporting of odor and air emissions. However, they also offer significant potential to be utilized as a screening tool for technology options that are being considered at early stages of wastewater upgrade and/or design projects, when engineers and operators are conceptualizing their process design and technology alternatives. The choice of the type of drop structures to be included in the influent collection system, technology options utilized in pretreatment steps as well as biological treatment and solids handling processes can have a significant impact on the emissions profile of a wastewater treatment process.This paper demonstrates the use of a fate and process model for compliance reporting and estimation of emissions from wastewater treatment systems. We demonstrate the use of Hydromantis’ Toxchem™ software, for selecting between design options for a wastewater treatment facility. In the two design cases that are considered, the choice of closed or open sewer reaches in the influent handling structure and diffused vs surface aerator options for aeration systems, are shown to provide a significant difference in emissions from the plant of 17.5% for the low emissions option (closed drop structure + diffused aeration) and 72.9% for the high emissions option (open drop structures + surface aerator).