This study quantifies volatile sulfur compound (VSC) emissions from primary settling tanks and investigates their mechanisms of generation. Hydrogen sulfide (H2S) and methyl mercaptan (MM) concentrations in the off‐gas were dominant among the VSCs analyzed, while dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) were under their odor threshold for most sampling dates. H2S emission in primary settling tanks was mainly the result of the stripping of dissolved sulfide (64%) generated in the sewers. Results indicate that MM emission was more dependent on the conditions in the primary clarifiers (only 16% stripping). Prevention of odor emission in primary settling tanks can be achieved by managing biofilms and microbial reactions in the sewer network. Controlling the biomass seeding and fermentation product availability in the primary settling tanks is essential to significantly minimize the kinetics of H2S and MM generation. Overall, the management of sludge blanket heights and thus avoiding time at low oxidation–reduction potential minimized odor emission independent of sewer conditions.
Practitioner points
H2S emission from primary clarifiers mainly originated from the stripping of the dissolved sulfide formed in the sewers.
MM emission contributed for 89% to overall odor emitted from primary clarifiers.
Seeding of active biomass from the sewer into the primary clarifiers was be the main driver for both MM and H2S formation.
Increased availability of fermentation products or fermenters increased MM production.
ContextMany patients who recovered from the acute phase of SARS-COV-2 infection have persistent symptoms. However, research regarding the prevalence of PCS symptoms in non-hospitalized primary care patients is scarce.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.