Odores em estações de tratamento de esgoto: qual a sua associação com o H2S?

Abstract

This study investigated the relationship between odours and hydrogen sulphide (H2S) in two distinct wastewater treatment plants (WWTP), one with an aerobic system and one with an anaerobic system, and analysed the effectiveness of the use of H2S as an indicator of odour, contributing to the improvement of odour monitoring and mitigation practices. For this purpose, odours and H2S were measured using field olfactometry (Nasal Ranger) and a H2S sensor (Acrulog H2S Parts per Billion Monitor), respectively. The results showed that only 34% of the measurements recorded odours and H2S simultaneously in the aerobic WWTP, whereas in the anaerobic WWTP this occurred in 83% of the cases. However, no significant correlations were found between the assessed parameters in either WWTP. Therefore, the results indicate that sensory techniques may be more suitable for assessing odours in WWTP, especially in aerobic systems, as compounds other than H2S may also contribute to odour emissions.