Odors associated with wastewater collection and treatment are a common problem. Wastewater odors are difficult to quantify, and current methods of quantification are too cumbersome to permit long-term evaluation of odor problems. In this project, residents in affected neighborhoods near a treatment plant in Winston-Salem, North Carolina quantified odors by completing numerical odor rating forms three times a day for six months. The resulting database was used to evaluate the correlation of odors to a variety of factors. Residents from the same neighborhood had a high level of agreement in quantifying odors, and most participants had a reasonable ability to make distinctions among different degrees of odor. Odors correlated well with wastewater characteristics (for example, influent COD) and wind direction, implicating the treatment plant as the major source of odors in affected neighborhoods. Use of the numerical odor rating form was an effective and inexpensive means of quantifying wastewater odors, and in conjunction with other information gave a better picture of specific major sources of odor at the treatment plant.
