These volatile reduced sulfur compounds comprise a major component of odors generated by wastewater treatment processes. The study correlates odor levels of dewatered biosolids to various operational parameters throughout the wastewater treatment process and forecasts total volatile reduced sulfur odor emissions of dewatered solids prior to recycling on agricultural fields. The model developed by this study indicates that the secondary blanket depth is the most significant factor for odor level of dewatered solids and that blanket depths more than 1.8 ft will cause a significant increase in odors. This model also found that polymer addition increases during the dewatering process as the odor and septicity of the dewatered solids increases.
Real-time monitoring and forecasting of odor after dewatering in wastewater treatment
A real-time odor monitoring system was developed to evaluate and predict odors levels of dewatered solids generated by the District of Columbia Water and Sewer Authority’s (DCWASA) advanced 370 mgd wastewater treatment plant (WWTP) in Washington, DC. Each year, DCWASA generates over 400,000 wet tons of biosolids and recycles these biosolids by applying them to over 20,000 acres of agricultural land. Nuisance odors from recycling biosolids on land may drift into surrounding neighborhoods and result in neighboring communities enacting legislation to ban land application, therefore, the reduction of odor emissions from biosolids recycled on field sites is a major concern. Odor levels generated by dewatered solids were measured as total volatile reduced sulfur compounds with an online electro-chemical headspace monitoring device.