Assessment of sulfide production in a full scale wastewater sludge rising main. (1st March 2018)

• Record Type: Journal Article
• Authors: Matos, Rita Ventura; Matias, Natércia; Ferreira, Filipa; Santos Silva, João; Matos, José Saldanha
• Is Part Of: Journal of environmental management. Volume 209(2018)
• Page Start: 505
• Page End: 514
• Publication Date: 2018-03-01
• Subjects: Biofilm -- Odor control -- Sludge handling -- Sulfate reducing bacteria -- Sulfide build-up; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2017.12.073
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Production and build-up of sulfide in wastewater systems, especially downstream of rising mains, may lead to severe odour nuisance, toxic environments and high risk of corrosion. Due to increased population migration towards cities and lower area availability for treatment facilities, rising mains for the conveyance of wastewater sludge are becoming more frequent, and research on sulfide build-up in such cases is needed. In this paper the findings of the work carried out in a full scale wastewater sludge rising main, operated during different seasons and under distinct conditions are presented (comprising both the start-up and normal operation stages of the facility). Results showed a sulfide build-up rate of 3.24 g S −2 m −2 d −1 in the summer and of 2.30 g S −2 m −2 d −1 during the winter. The ratio of sulfate reduction to sulfide production (SO4 −2 /S −2 ) was of roughly 3 to 1, as expected. Furthermore, obtained results allowed adjusting a second order polynomial empirical equation for the forecasting of sulfide build-up within the sludge rising main. The obtained equation for sludge significantly differs from existing equations obtained for wastewater. Moreover, this work also allowed obtaining new insight into the positive influence of biofilm and hydraulic retention time in the biological sulfide generation, as well as into its variation along the length of the rising main. Graphical abstract: Image 1 Highlights: Sulfide build-up in a sludge rising main appears to correlate with soluble COD. A 2nd order polynomial equation was obtained to predict sulfide formation. Spatial variability in biofilm activity and sulfide generation was observed. Sulfate reducing bacteria took about 5 weeks to colonize the sludge force main wall. Simultaneous release of methane and hydrogen sulfide was observed during the summer.