Long term effects of salt on activity, population structure and floc characteristics in enriched bacterial cultures of nitrifiers

Effects of salinity build-up on biomass characteristics and trace organic chemical removal: Implications on the development of high retention membrane bioreactors

“…However, the removal of NH 4 + -N by the saline-MBR decreased markedly from almost 100% to 38% when the NaCl concentration increased up to 6 g/L. This observation is consistent with previous studies where high salinity has been reported to adversely affect the nitrification process through inhibiting the metabolic activity and growth rate of nitrifying bacteria (or nitrifiers) during biological treatment (Moussa et al, 2006;Yogalakshmi and Joseph, 2010). Similar to the variations in removal of both TOC and TN, NH 4 + -N removal in the saline-MBR gradually improved and remained at nearly 80% from day 38 onward, even though the NaCl loading was continuously increased to 16.5 g/L.…”

Nitrification in fixed-bed reactors treating saline wastewater

“…Specific inhibitors such as allythiourea and sodium azide should be applied to facilitate the separate investigation of AOB and NOB activities (Sanchez et al 2005). A higher sensitivity of AOB to high salt concentrations of pure cultures was reported (Moussa et al 2006). Controverse results were found by Kawasaki et al (1996) or Vredenbregt et al (1997).…”

“…An often reported but not always successful approach for biological nitrification of saline wastewater is the stepwise adaption of non-saline water bacteria to halophilic conditions (e.g. Moussa et al 2006). Adaption of a sweat water nitrifying population to saltwater conditions of up to 40 g L -1 NaCl seems not to be possible (Moussa et al 2006), whereas an enrichment of halophilic nitrifiers from halophilic environmental sources would be a more promising approach, since most halophilic nitrifiers are apparently ubiquitous in seawater environment (Francis et al 2005).…”

Investigation of microbial adaptation to salinity variation for treatment of reverse osmosis concentrate by membrane bioreactor

“…In the case of instant salt shock, ammonia removal efficiency decreased from 95 to 46% as the salt concentration increased from 0 to 20 g NaCl/L (Table 3). According to Moussa et al [15], ammonia oxidizers are more sensitive to salt stress than heterotrophs removing organic matter. That indicated that freshwater nitrifiers are very sensitive to high salinity, and once they are affected or washed out, considerable time will be required to reestablish them due to their slow growth rates.…”