Preliminary assessment of the impact of thermal drying on volatile sulfur emissions from dewatered biosolids

A preliminary assessment of the potential impact of thermal drying on volatile sulfur and odour emissions from dewatered biosolids was conducted. It should be noted that a single sample of each dewatered product (one sample per WWTP, for three samples of dewatered product in total) was utilised in this study. Hydrogen sulfide and dimethyl disulfide were consistently present and dominant in the odour emissions from both the dewatered and dried products. The dried product had elevated levels of carbon disulfide and carbonyl sulfide compared to the associated dewatered cake. Drops in VSC concentrations on the order of 90% or greater (and odour concentrations on the order of 20-50%) were observed during the first 24 hour period following wetting and mixing with soil. Significant attenuation (on the order of 80%) of most VSC concentrations, and odour emissions reductions on the order of 50% occurred over the seven day post mixing period studied.