Achieving the nitrite pathway using aeration phase length control and step‐feed in an SBR removing nutrients from abattoir wastewater

Abstract

Aeration phase length control and step-feed of wastewater are used to achieve nitrogen removal from wastewater via nitrite in sequencing batch reactors (SBR). Aeration is switched off as soon as ammonia oxidation is completed, which is followed by the addition of a fraction of the wastewater that the SBR receives over a cycle to facilitate denitrification. The end-point of ammonia oxidation is detected from the on-line measured pH and oxygen uptake rate (OUR). The method was implemented in an SBR achieving biological nitrogen and phosphorus removal from anaerobically pre-treated abattoir wastewater. The degree of nitrite accumulation during the aeration period was monitored along with the variation in the nitrite oxidizing bacteria (NOB) population using fluorescence in situ hybridization (FISH) techniques. It is demonstrated that the nitrite pathway could be repeatedly and reliably achieved, which significantly reduced the carbon requirement for nutrient removal. Model-based studies show that the establishment of the nitrite pathway was primarily the result of a gradual reduction of the amount of nitrite that is available to provide energy for the growth of NOB, eventually leading to the elimination of NOB from the system.

Batch treatment of liquid fraction of pig slurry by intermittent aeration: process simulation and microbial community analysis

“…Interrupting the airflow at a lower DO set-point would therefore result in a greater reduction of the nitrite-oxidizing activity. 39 Significant oxygen savings of up to 43% were achieved in AS3 with respect to AS1. On the other hand, a worsening of the sludge settleability was detected.…”

Removal of veterinary antibiotics from sequencing batch reactor (SBR) pretreated swine wastewater by Fenton's reagent

“…In recent years, sequencing batch reactor (SBR) has been successfully employed to remove COD, SS and nutrients from animal wastewaters (Dosta et al, 2008;Lemaire et al, 2008). However, it is reported that the biological technique is often not effective in degrading many antibiotics, for example, sulfonamides, tetracyclines and macrolides (McArdell et al, 2003;Kim et al, 2005;Batt et al, 2007).…”

Achieving nitrite accumulation in a continuous system treating low-strength domestic wastewater: switchover from batch start-up to continuous operation with process control

“…However, partial nitrification to nitrite in continuous reactors might be achieved by switching from the batch start-up into continuous operation. Recently, a number of operational factors for achieving partial nitrification to nitrite have been investigated mainly in SBRs, which demonstrated low DO concentration (Aslan et al 2009;Blackburne et al 2008a;Ye and Zhang 2010), high temperatures (Kim et al 2008), relatively high FA and free nitrous acid (FNA) concentrations Yamamoto et al 2008;Aslan and Dahab 2008), on-line aeration duration control (Guo et al 2009a;Lemaire et al 2008;Antileo et al 2006;Jubany et al 2008;Peng et al 2004;Blackburne et al 2008b), appropriate sludge age (Gee and Kim 2004;Hellinga et al 1998), saline inhibition (Ye et al 2009;Sudarno et al 2010), and periodic anoxic disturbances (Kornaros et al 2010;Kornaros et al 2008) were favorable for selectively inhibiting or limiting the growth of NOB. The control of aeration duration is one of economically feasible methods, since appropriated aeration duration can save the oxygen consumption.…”