Development of an odor wheel classification scheme for wastewater

Abstract

Overall, in the air pollution control field, odor concentration and intensity as well as hedonic rating have been well studied to the point where some level of standardization is being developed or is already in place. However, there has been no standardization with respect to odor quality characterization. There is now sufficient understanding of the types of odorous compounds that can arise from wastewater treatment processes to develop an odor classification scheme. This article presents the first wastewater odor wheel or classification scheme that should form the foundation for the evolution of odor quality data reporting with links to chemical causes.

A framework for identifying characteristic odor compounds in municipal wastewater effluent

“…1). Additionally, the threshold at which odor compounds were reported as weak (intensity rating ¼ 2) agreed with the reported odor thresholds reported for 2-methylisoborneol (5e15 ng/L), 2,4,6-trichloroanisole (0.1e2 ng/L), and geosmin (1e10 ng/L) (Young et al 1996, Burlingame et al 2004, Peter et al 2009). …”

“…Search results were then prioritized by match probability and compared to previously reported odorous compounds or compound classes reported in peer-reviewed publications and publicly available commercial odorant databases (APHA 1997, GSC 2011, SigmaeAldrich 2011, Dunkel et al 2008, Burlingame et al 2004, Young et al 1996.…”

“…Biological wastewater treatmentdespecially anaerobic processesdoften release sulfidic and putrid/rancid odors associated with reduced sulfur-or nitrogen-containing compounds, organic acids, aldehydes or ketones (Gostelow et al 2001, Burlingame et al 2004. Sludge digestion also can result in the release of putrescent, greasy, and cabbage-like odors from wastewater treatment plants (Lambert et al 2000, Visan and Parker 2004, Suffet et al 2009).…”

“…Previous efforts to identify odorous compounds in drinking water have employed flavor profile analysis (FPA)da process in which panels of trained human analysts describe and categorize odorants according to categories related to their source and chemical structure (Burlingame et al 2004, Andersson et al 2005, Lambert et al 2000, Young et al 1996. The qualitative descriptions of odorants from sensory panels are then frequently used to guide analysis by gas chromatography coupled with various types of detectors (Brownlee et al 1993, Hwang et al 1995, Lermussieau et al 2001, Gostelow et al 2001, Cancho et al 2001, Benanou et al 2003, Diaz et al, 2005, Hochereau and Bruchet, 2004, Strube et al 2009, Peter et al 2009, Zarra et al 2009).…”

“…Even with careful selection and training of analysts to detect and describe effluent odors, variability was still present in the qualitative odor descriptions and intensity ratings due to the subjective nature of sensory anlysis. To minimize the potential for bias, analysts participating in the study were trained on odor descriptor identification using FPA reference standards described in Standard Method 2170B (APHA 1997) and additional compounds identified in the wastewater and drinking water odor wheel (Burlingame et al 2004). Specific odor descriptors and more general odor categories information were collected during the initial peak identification phase of this study.…”