Nitrogen removal from slaughterhouse wastewater through partial nitrification followed by denitrification in intermittently aerated sequencing batch reactors at 11°C

Abstract

This study is aimed to examine the removal of nitrogen from high strength slaughterhouse wastewater at 11 degreeC via partial nitrification followed by denitrification (PND), using the intermittently aerated sequencing batch reactor (IASBR) technology. The slaughterhouse wastewater contained chemical oxygen demand (COD) of 6068 mg/L, total nitrogen (TN) of 571 mg/L, total phosphorus (TP) of 51 mg/L and suspended solids of 1.8 g/L, on average. The laboratory-scale IASBR reactors had a working volume of 8 L and was operated at an average organic loading rate of 0.61 g COD/(L-d). At the cycle duration of 12 h, COD was efficiently removed under three aeration rates of 0.4, 0.6 and 0.8 L air/min. Among the three aeration rates, the optimum aeration rate was 0.6 L air/min with removals of COD, TN, and TP of 98%, 98%, and 96%, respectively. The treated wastewater met the Irish emission standards. The microbial community analysis by fluorescence in situ hybridization shows 12 +/- 0.4% of ammonium oxidizing bacteria, and 7.2 - 0.4% of nitrite oxidizing bacteria in the general bacteria (EUB) in the activated sludge at the aeration rate of 0.6 L air/min, leading to efficient partial nitrification. PND effectively removed nitrogen from slaughterhouse wastewater at 11degreeC, but PND efficiency was dependent on the aeration rate applied. PND efficiencies were up to 75.8%, 70.1% and only 25.4% at the aeration rates of 0.4, 0.6, and 0.8 L air/min.

Slaughterhouse wastewater characteristics, treatment, and management in the meat processing industry: A review on trends and advances

“…Kinetic coefficients were also determined. Pan et al (2014) evaluated the removal of TN from SWW at low temperatures of up to 11 C through partial nitrificationedenitrification by means of an 8-L SBR. The influent concentration of the SWW contained COD, TN, TP, and TSS concentrations of 6068, 571, 51, 1800 mg/L, respectively.…”

Simultaneous Heterotrophic Nitrification and Aerobic Denitrification byChryseobacteriumsp. R31 Isolated from Abattoir Wastewater

“…Meyer et al [5] noted that nitrification and denitrification would be incompletely coupled to each other due to nonformation of aerobic/anoxic zones within the microbial aggregates, resulting in buildup of NO x − in the reactor. In comparison with the conventional nitrification and denitrification of abattoir wastewater, several advantages of a shortcut nitrogen removal method via nitrite, through partial nitrification followed by denitrification (PND), have been reported recently [6]. …”

“…Furthermore, SND processes are characterized by increased nitrogen removal rates and decreased reaction time. The key point in the PND process is maintaining the production rate of nitrite by ammonium oxidizing bacteria (AOB) higher than the production rate of nitrate by nitrite oxidizing bacteria (NOB) so that nitrite accumulation can be achieved [6]. In contrast, maintenance of a population balance is not necessary in SND as the two reactions (nitrification and denitrification) proceed under identical reaction conditions.…”

A Critical Review on Processes and Energy Profile of the Australian Meat Processing Industry

“…In the third stage the aerated wastewater is given a time for TSS to settle and finally the supernatant is discharged in the fourth stage. Although some studies have demonstrated high nutrients and COD removal using aerobic SBR [54,55], judging from the mixing and fluid transport requirements one can infer that this process is an energy intensive one.…”