Complete nitrogen removal from municipal wastewater via partial nitrification by appropriately alternating anoxic/aerobic conditions in a continuous plug-flow step feed process

Partial nitrification and denitrification in a sequencing batch reactor treating high-salinity wastewater

“…Therefore, main characteristic of the process is the enrichment of ammonium-oxidizing bacteria (AOB) and inhibition of nitrite-oxidizing bacteria (NOB) [1]. In order to inhibit the activity of NOB, some operation conditions have been used, including high temperature, appropriate pH, low dissolved oxygen (DO) concentration, appropriate sludge retention time (SRT), high substrate concentration, high free ammonia (FA) concentration and aeration pattern [3][4][5][6]. Temperature and DO are competitive factors which do not inhibit nitrite oxidizers but can give a competitive advantage to ammonia oxidizers over the nitrite oxidizers, while free ammonia or toxic compounds are inhibitory factors that have a selective inhibition on the nitrite oxidizers and a minimal effect on the ammonium oxidizers [7].…”

Nitrate Removal from Wastewater through Biological Denitrification with OGA 24 in a Batch Reactor

“…As demonstrated by the most recent literature, new bacterial strains are continuously isolated and tested for their NO3 − removal abilities [9][10][11][12][13]. Depending on their characteristics, different bacteria are employed in different waste treatment facilities, with a preference towards those microorganisms capable of combined heterotrophic nitrification and aerobic denitrification.…”

The challenges of mainstream deammonification process for municipal used water treatment

“…As such, NOB can be continuously washed out of the system. Although extensive efforts have been dedicated to various attempts including intermittent aeration (Ge et al 2014), real-time control of aeration (Claros et al 2012), inorganic carbon (NaHCO 3 ) (Tokutomi et al 2010), and bioaugmentation with AOB (Bartrolí et al 2011) to maintain sustainable mainstream nitritation, it is of yet-resolved challenge. So far, most commonly practiced engineering approaches towards nitritation are based on the alternating dissolved oxygen (DO) control and short SRT .…”

“…This strategy has been adopted for the treatment of both high-and lowammonium used water (Blackburne et al 2008;Fernandes et al 2013;Ruiz et al 2003). However, recent studies showed that higher DO of around 1.5 mg/L was still beneficial to (Cao et al 2013;Ge et al 2014;Regmi et al 2014). Using a tropical full-scale used water treatment plant in Singapore as the case study, Cao et al (2013) showed that 75 % of nitrite accumulation was achieved in the oxic units operated at the DO concentrations of 1.4-1.8 mg/L.…”

“…Another approach is to use step-feed reactor configuration. Stable partial nitritation/denitritation had been reported in continuous plug-flow reactors with alternate anoxic and oxic (A/O) zones (Cao et al 2013;Ge et al 2014). However, it should be noted that such control strategy still needs further study in a sustainable mainstream deammonification process for municipal used water treatment.…”