Effects of high salinity wastewater on methanogenic sludge bed systems

Abstract

The attainable loading potentials of anaerobic sludge bed systems are strongly dependent on the growth of granular biomass with a particular wastewater. Experiments were conducted to determine the effects of high salinity wastewater on the biological and physical properties of methanogenic sludge. Sodium concentration of 5 g/L and 15 g/L were added to the influent of upflow anaerobic sludge bed (UASB) systems. After 100 days of operation, the methanogenic activity, extracellular polymeric substances (EPS), and granular strength were analyzed. The results show a high removal of organic matter but with accumulating propionate concentrations in the effluents. Meanwhile, wash-out of active methanogenic biomass in the effluent of the reactors was observed, likely as a results of the high Na+ concentrations. The rinsed biomass was characterized by a considerable specific methanogenic activity (SMA) on acetate, propionate and hydrogen as the substrates. On the other hand, results show that the SMA evolution was not affected by high salt concentrations. Also the amount and composition of extracellular polymeric substances (EPS) were similar in all sludges. However, results clearly show a sharp drop in the granule strength as a results of high Na+ concentration.

Strength characterization of full-scale aerobic granular sludge

“…For this study, a method was evaluated to quantify the influence of variations in bulk liquid composition, more specific salinity, on the physical strength of granular sludge. Previous studies have shown a negative effect of NaCl on the strength of anaerobic granular sludge [22]. Displacement of Ca 2+ ions by Na + was suggested to be the major cause for this observation [23].…”

Celebrating 40 years anaerobic sludge bed reactors for industrial wastewater treatment

“…HRT, VLR, temperature, pH, upflow velocity, presence of divalent cations and heavy metals, salinity, and nutrient availability (Habeeb et al 2011;Abbasi and Abbasi 2012;Calderon et al 2013;Ismail et al 2008). The seed sludge and the chemical composition of the industrial wastewater have significant impact on the chemical composition of the granular sludge (Batstone et al 2004).…”

Microbial Community Drivers in Anaerobic Granulation at High Salinity

“…In sludge granulation, granule strength and stability is considerably reduced in presence of high concentrations of Na + , leading to displacement of the bridging Ca 2+ ions within the EPS matrix (Lambert et al, 1975;Bruus et al, 1992;Ismail et al, 2010). As consequence, non-adapted granules disintegrate, causing biomass wash-out and deteriorating process performance (Rinzema et al, 1988;Vallero et al, 2003;Ismail et al, 2008). Still, utilization of salinity adapted biomass was successfully applied to overcome this issue and obtain strong aggregates/granules (Feijoo et al, 1995;Hierholtzer and Akunna, 2014;Gagliano et al, 2017;Sudmalis et al, 2018).…”

“…Previous research investigating UASB reactors operated at high salinity (Rinzema et al, 1988;Vallero et al, 2003;Ismail et al, 2008Ismail et al, , 2010Li et al, 2014;Aslan andŞekerdag, 2015;Gagliano et al, 2017;Sudmalis et al, 2018) did not carefully address the microbial ecology and its importance in driving aggregation and granules formation.…”