The effects of salinity on nitrification using halophilic nitrifiers in a Sequencing Batch Reactor treating hypersaline wastewater

Abstract

With annual increases in the generation and use of saline wastewater, the need to avoid environmental problems such as eutrophication is critical. A previous study identified ways to start up a halophilic sludge domesticated from estuarine sediments to remove nitrogen from wastewater with a salinity of 30 g/L. This investigation expands that work to explore the impact of salinity on nitrogen removal. This study demonstrated that the mixed halophilic consortia removed nitrogen from wastewater with a salinity of 30–85 g/L. A kinetic analysis showed that halophilic nitrifiers selected based on hypersalinity were characterized by low Ks, μmax and specific ammonium oxidization rates. This explains the decrease in ammonium removal efficiency in the high salinity operational phases. Salinity inhibited ammonia oxidizing bacteria (AOB) activity, as well as the number of dominant AOB, but did not significantly affect the AOB dominant species. Three most dominant AOB lineages in the halophilic sludge were Nitrosomonas marina, Nitrosomonas europaea, and Nitrosococcus mobilis. Nitrosomonas europaea and Nitrosococcus mobilis were mainly affected by salinity, while nitrite accumulation and ammonia loading played the key role in determining the abundance of Nitrosococcus mobilis and Nitrosococcus europaea. The study contributes insights about shifts in halophilic nitrifying bacterial populations.

Enhanced carbon and nitrogen removal performance of simultaneous anammox and denitrification (SAD) with mannitol addition treating saline wastewater

“…The same study also found that relative enzyme activities of lipase and nitrate reductase increased by 32% and 35%, respectively, in the presence of 1 mmol L −1 ectoine. 18 Liu et al 16 found that 1 mmol L −1 glycine betaine was most effective in alleviating salt toxicity in anammox biomass. It is likely that different compatible solutes have different mechanisms and different optimum addition on AnAOB and HDB.…”

“…However, acclimatization time may be quite long and microbial salt resistance can be easily lost if the salt concentration selection pressure is removed . Although microorganisms are able to survive in high salinity environments through bio‐augmentation with halophilic species to achieve more stable and durable process performance, it is not easy to maintain dominance of such species in mixed culture systems …”

“…It was found that ectoine resulted in faster denitrification and trehalose had no effect on nitrate removals. 18 Liu et al 16 found that 1 mmol L −1 glycine betaine addition was most effective in alleviating salt toxicity in anammox biomass obtained from a pilot-plant UASB. To the best of our knowledge, no studies have focused on the effect resulting from mannitol addition to the SAD process to treat saline wastewater.…”

Response of ammonia-oxidizing Bacteria and Archaea to long-term saline water irrigation in alluvial grey desert soils

“…Nitrification in soils is a central component of N biogeochemical cycling and involves the oxidation of ammonia + (NH ) 4 to nitrite − (NO ) 2 , along with further oxidation to nitrate − (NO ) 3 . The process has significant environmental and agricultural impacts on N nutrient availability for plants, NO 3 − N leaching, and greenhouse gases emissions [1][2][3] . Specifically, ammonia oxidation and nitrite oxidation are the two key steps of nitrification.…”

A study to use activated sludge anaerobic combining aerobic for treatment of high salt seafood processing wastewater

“…In addition, high salt content induces cell lysis, which causes increased effluent solids. The populations of protozoa and filamentous organisms required for proper flocculation were also significantly reduced by the elevated salt content [13][14][15][16][17] . Therefore, high salinity in fish processing wastewater will lead to difficulties in biological treatment processes 13 .…”