Effect of Sulphide on Enhanced Biological Phosphorus Removal

Abstract

Due to the different processes that can generate sulphate rich wastewaters (with up to 500 mg SO 4 2-/L), its occurrence in the inlet of wastewater treatment plants (WWTP) is likely to happen. Sulphate can be reduced to sulphide during sewage conveyance or in the different anaerobic tanks of the wastewater treatment plants (Bentzen et al., 1995; Poinapen et al., 2009). Certainly, these wastewater streams require proper treatment prior to discharge into surface water bodies. While COD and nitrogen removal can be satisfactorily achieved, the biological Chapter 1 This PhD studies aims to get a better understanding about the effects of sulphide on the dominant microbial populations involved in EBPR. This can contribute to improve and secure the satisfactory biological removal of phosphorus, when is exposed to the sulphide produced in the sewage (short term exposure) or at the WWTP (long term exposure). Probes Specify Reference ACA652 Acinetobacter Wagner et al. (1994) PAO462, PAO651, PAO846 Most Accumulibacter Crocetti et al. (2000) Acc-1-444 C. Accumulibacter clade I Flowers et al. (2008) Acc-2-444 C. Accumulibacter clade 2 Flowers et al. (2008) Actino-221 a , Actino-658 a Actinobacteria Kong et al. (2005) Tet3-654, Tet2-842, Tet2-831, Elo1-1250, Tet1-266 Tetrasphera Nguyen et al. (2011) BEG811 Beggiatoa Macalady et al. (2006) Not found Thiomargarita namibiensis a It requires a helper probe 1.3.3. Functional differences of Candidatus Accumulibacter phosphatis Biological nutrient removal treatment plants aim to remove phosphorus and nitrogen from wastewater. As nitrate is an electron acceptor that can be used instead of oxygen for the generation of energy, past studies focused on the ability of Candidatus Accumulibacter phosphatis (hereafter referred as PAO) to use nitrate for the uptake of phosphorous (Kerrn-Jespersen et al., 1993; Kuba et al., 1993). Later studies, based on laboratory and pilot scale experiments, showed that anoxic phosphorus uptake was possible (Kuba et al., 1997a, 1997b; Kim et al., 2013). Nevertheless, they observed that the ability to use nitrate as electron acceptor 1.5. Research approach Due to the potential ability of Candidatus Accumulibacter phosphatis clade I (PAO I) to denitrify and in order to compare the effects of sulphide on the anaerobic-anoxic-aerobic metabolism of PAO, an enriched culture of PAO I was used. In the first stage it was assessed the potential effect of different electron acceptors on the activity of sulphate reducing bacteria (SRB) (figure 1.1). To do so the activity of an enrich biomass of SRB was measured after its exposure during 2h to a similar concentration of oxygen, nitrate or nitrite to the ones observe 2.1. Highlights • Oxygen is the most inhibiting electron acceptor to the sulphate reduction activity. • Inhibition is more pronounced when sulphate reduction bacteria (SRB) are fed with acetate. • The activity of sulphate reduction bacteria (SRB) may be prevented by applying an anaerobic contact time shorter than 0.4 h in conventional BNR systems.

Ionic Strength of the Liquid Phase of Different Sludge Streams in a Wastewater Treatment Plant

“…The concentration for these elements can be 5-10 times higher than the maximum range given if seawater is used as flushing water like in Hong-Kong (17,18,19). Sulphate and chloride are also commonly added in WWTPs as counter-ion of iron or aluminium (used to flocculate the sludge and remove phosphate), and present in industrial wastewater (16). (5,20).…”

Ionic Strength of the Liquid Phase of Different Sludge Streams in a Wastewater Treatment Plant

“…The concentration for these elements can be 5-10 times higher than the maximum range given if seawater is used as flushing water like in Hong-Kong (17,18,19). Sulphate and chloride are also commonly added in WWTPs as counter-ion of iron or aluminium (used to flocculate the sludge and remove phosphate), and present in industrial wastewater (16). of the dissolved sulphur is sulphide after thickening of PS and WAS according to (5).…”