Stability of Volatile Sulfur Compounds (VSCs) in sampling bags – impact of temperature

Abstract

Volatile sulfur compounds (VSCs) are a major component of odorous emissions that can cause annoyance to local populations surrounding wastewater, waste management and agricultural practices. Odour collection and storage using sample bags can result in VSC losses due to sorption and leakage. Stability within 72 hour storage of VSC samples in three sampling bag materials (Tedlar, Mylar, Nalophan) was studied at three temperatures: 5, 20, and 30 °C. The VSC samples consisted of hydrogen sulfide (H2S), methanethiol (MeSH), ethanethiol (EtSH), dimethyl sulfide (DMS), tert-butanethiol (t-BuSH), ethylmethyl sulfide (EMS), 1-butanethiol (1-BuSH), dimethyl disulfide (DMDS), diethyl disulfide (DEDS), and dimethyl trisulfide (DMTS). The results for H2S showed that higher loss trend was clearly observed (46-50% at 24 hours) at 30 °C compared to the loss at 5 °C or 20 °C (of up to 27% at 24 hours) in all three bag materials. The same phenomenon was obtained for other thiols with the relative recoveries after a 24 hour period of 76-78% at 30 °C and 80-93% at 5 and 20 °C for MeSH; 77-80% at 30 °C and 79-95% at 5 and 20 °C for EtSH; 87-89% at 30 °C and 82-98% at 5 and 20 °C for t-BuSH; 61-73% at 30 °C and 76-98% at 5 and 20 °C for 1-BuSH. Results for other sulfides and disulfides (DMS, EMS, DMDS, DEDS) indicated stable relative recoveries with little dependency on temperature (83-103% after 24 hours). DMTS had clear loss trends (with relative recoveries of 74-87% in the three bag types after 24 hours) but showed minor differences in relative recoveries at 5, 20, and 30 °C.

Impact of Storage Conditions on the Stability of Volatile Sulfur Compounds in Sampling Bags

“…The loss predictions for DMDS and DEDS in this paper were based on the assumption that there were sufficiently high initial amounts of these two VSCs in the sample bags. In the case of samples with very low initial amounts of the two VSCs and high amounts of MeSH and EtSH, the evolution of the relative recovery results for DMDS and DEDS would be very different according to Le et al (2013).…”

“…Besides bag materials, the impact of other storage factors on the losses of VSCs has also been investigated. Those factors include light exposure (Mochalski et al, 2009; Sulyok et al, 2001), temperature (Le et al, 2013), and sample relative humidity (RH) (Mochalski et al, 2013). However, the effects of the additional factors in those studies appeared to be investigated just as sidelines for the main factor of bag materials.…”

Gaseous Emissions from Wastewater Facilities

“…Microaeration has recently been proven as a relatively simple and highly efficient biological method for sulfide removal in the anaerobic digestion of biosolids. Jenicek et al (2013) (Le et al, 2013). Capelli et al (2013) reviewed the different odor sampling strategies adopted for the estimation of odor emission rates (OER) from different source types, including an overview of odor sampling regulations and a detailed discussion of the equipment and the mathematical considerations.…”

H2S Loss through Nalophan™ Bags: Contributions of Adsorption and Diffusion

“…H 2 S is detected by human olfaction at very low concentrations—about 1 ppb [37–39]—and it is typically found in the emissions from different plants, like industry [30], agriculture [16, 31], waste water treatment [7], and waste treatment [21]. …”