Process Control of an Alternating Aerobic‐Anoxic Sequencing Batch Reactor for Nitrogen Removal via Nitrite

Abstract

Nitrogen removal via nitrite is a novel technology and is becoming popular for engineering applications since it results in a saving of the aeration energy required for nitritation and external carbon sources for denitritation. An alternating aerobic-anoxic (AAA) operational pattern was applied in a sequencing batch reactor (SBR) process to improve the nitrogen removal efficiency and achieve partial nitrification via nitrite from industrial wastewater with influent alkalinity deficiencies. The results showed that the online monitoring of the pH-time variations during nitrification could indicate if the alkalinity was sufficient and when the ammonia nitrogen was completely oxidized. Under conditions of deficient influent alkalinity, the AAA process reduced the external alkalinity and the carbon sources addition and improved the effluent quality with ammonia nitrogen concentration below the detection limits. Half of the alkalinity previously consumed during aerobic nitrification could be recovered during the subsequent anoxic denitrification period. If the cycles of alternating aerobic/anoxic were repeated more than twice, the first nitrification cycle was stopped when the pH decreased by 0.4-0.5. The middle nitrification was terminated when the pH decreased by 0.8-1.0, and the final nitrification duration was controlled by the dissolved oxygen (DO) breakpoint and ammonia valley on the pH profile. Each anoxic timescale for denitrification was determined by the nitrate knee on the oxidation-reduction potential (ORP) profile and the nitrate apex on the pH profiles. In comparison to the conventional SBR process, the AAA process with a real-time control strategy resulted in an improved nitrogen removal efficiency of greater than 97 % under conditions of deficient influent alkalinity. Moreover, nitrogen removal via nitrite was achieved with a nitrite accumulation rate above 95 %.

Partial nitrification and nutrient removal in intermittently aerated sequencing batch reactors treating separated digestate liquid after anaerobic digestion of pig manure

“…Using partial nitrification followed by ANAMMOX for BNR saves 25% of the aeration cost in nitrification and does not require the addition of external organic carbon in the denitrification step. Efficient partial nitrification has been observed in intermittently aerated sequencing batch reactors (IASBRs) treating wastewater [13,14]. It is reported that IASBRs treating slaughterhouse wastewater achieved a NO 2 --N level of up to 96% of the total oxidized nitrogen (TON, NO 2 --N and NO 3 --N), in addition to COD and total nitrogen (TN) removals from wastewater of more than 94 and 92%, respectively [15,16].…”

Kinetic Model for Biological Nitrogen Removal Using Shortcut Nitrification-Denitrification Process in Sequencing Batch Reactor

“…Although two-step nitrification has been modeled previously , , the model for shortcut nitrification−denitrification kinetics has not been reported. Sequencing batch reactor (SBR) has been widely used in wastewater treatment not only for organic removal but also for nutrient removal including nitrogen and phosphorus ,, . SBR system is especially effective for biological nitrogen removal.…”

Interaction between Biological Nitrogen Removal Processes and Operating Parameters: A Review

“…High temperature of 28 -38 °C was favorable for nitrogen removal via nitrite due to the fact that the specific growth rate of AOB was higher than NOB [51]. Nitritation can be maintained at room or low temperature and nitratation start-up can be promoted and accelerated at high temperature [52]. In temperature 10 -20 °C resulted a very low nitrite accumulation due to high specific growth rate of NOB than AOB [53].…”