A comprehensive comparison between halophilic granular and flocculent sludge in withstanding short and long-term salinity fluctuations. (April 2018)

• Record Type: Journal Article
• Authors: Corsino, Santo Fabio; Capodici, Marco; Torregrossa, Michele; Viviani, Gaspare
• Is Part Of: Journal of water process engineering. Volume 22(2018)
• Page Start: 265
• Page End: 275
• Publication Date: 2018-04
• Subjects: AGS aerobic granular sludge -- AUR ammonium utilization rate -- BOD5 biochemical oxygen demand -- COD chemical oxygen demand -- EPS extracellular polymeric substances -- F/M food vs microorganism ratio -- FAS flocculent activated sludge -- HRT hydraulic retention time -- LT long term -- MLTSS mixed liquor total suspended solids -- MLVSS mixed liquor volatile suspended solids -- NUR nitrite utilization rate -- OLR organic loading rate -- PLC programmable logic controller -- PN proteins -- PS polysaccharides -- PSD particle size distribution -- SRT sludge retention time -- ST short-term -- TN total nitrogen -- TSS total suspended solids -- UC uniformity coefficient -- VSS volatile suspended solids -- WWTPs wastewater treatment plants; Aerobic granular sludge -- Fish-canning wastewater -- Salinity shocks -- FAS -- Shortcut nitrification/denitrification; Water-supply engineering -- Periodicals; Saline water conversion -- Periodicals; Seawater -- Distillation -- Periodicals; Sanitary engineering -- Periodicals; Sewage -- Purification -- Periodicals; 627
• DOI: 10.1016/j.jwpe.2018.02.013
• Languages: English
• ISSNs: 2214-7144

Abstract

Graphical abstract: Highlights: Salinity shocks effects on granular and flocculent sludge were compared. Nitritation and denitritation kinetics were evaluated. Autotrophic bacteria did not suffer severe loss in biological activity. Capability of halophilic biomass to withstand to high salinity was outlined. Granular sludge faced to salinity fluctuations better than flocculent sludge. Abstract: The effects of salinity fluctuations on the activity of autochthonous halophilic bacteria in aerobic granular sludge (AGS) and flocculent activated sludge (FAS) reactors were investigated. The response of nitrifiers and denitrifiers activity to drastic and moderate salinity shocks in the short-term (ST) and long-term (LT) was examined. The BOD5 removal efficiency decreased only in the reactors subjected to the drastic LT salinity increase. Nevertheless, stable performances were achieved 18 days after the shock in the AGS-R1 (90%), whereas after 27 days in the FAS-R1 (82%). The loss in nitritation efficiency was higher in the FAS reactors and was proportional to the shock intensity. Nitritation activity collapsed from approximately 3.8 mgNH4 -N gVSS −1 h −1 to 0.73 mgNH4 -N gVSS −1 h −1 and from 4.5 mgNH4 -N gVSS −1 h −1 to 0.24 mgNH4 -N gVSS −1 h −1 in the AGS-R1 and FAS-R1, respectively, even if the ammonium oxidation capacity did not completely disappeared. Denitritation activity decreased from 11.44 mgNO2 -N gVSS −1 h −1 to 3.93 mgNO2 -N gVSS −1 h −1 in the AGS-R1 at steady state, whereas in the FAS-R1, it decreased from 12.53 mgNO2 -N gVSS −1 h −1 to 2.09 mgNO2 -N gVSS −1 h −1 . Nitritation and denitritation were completely restored 5 days after ST shock. No significant effects were observed after the moderate shock. The changes in the total EPS content were lower than 10%, therefore, it was considered negligible. Only drastic shocks caused significant changes in the EPS structure, with an increase of the loosely-bound by 45% in the AGS and 55% in the FAS.