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Long-term partial nitrification in an intermittently aerated sequencing batch reactor (SBR) treating ammonium-rich wastewater under controlled oxygen-limited conditions

Paper ID Volume ID Publish Year Pages File Format Full-Text
3734 184 2011 8 PDF Available
Title
Long-term partial nitrification in an intermittently aerated sequencing batch reactor (SBR) treating ammonium-rich wastewater under controlled oxygen-limited conditions
Abstract

In this study, a novel technology was developed to achieve efficient partial nitrification at moderately low temperature, which would save the aeration cost and have the capacity to treat a wide range of ammonium-rich wastewaters with low chemical oxygen demand-to-nitrogen (COD:N) ratios. At pH of 7.1–7.4 and a sludge retention time (SRT) of greater than 100 days, a laboratory-scale intermittently aerated sequencing batch reactor (IA-SBR) was operated at about 20 °C to treat synthetic wastewater containing readily biodegradable COD of 100–300 mg L−1 and ammonium–nitrogen (NH4+–N) of 300 mg L−1. During the aeration periods, DO concentrations were controlled at less than 0.2 mg L−1, and the aeration was terminated when on-line NH4+–N measurement reached 20 mg L−1. During 180 days of operation, the mass ratio of nitrite–N (NO2−–N) to the total oxidized nitrogen was over 90% in the effluent. Molecular analyses show that ammonium oxidizing bacteria (AOB) represented up to 10% of the total bacterial population in the sludge biomass, and the ratio of AOB to nitrite oxidizing bacteria (NOB) was generally over 100. The IA-SBR quickly recovered after non-operation for 47 days. The three main factors enabling long-term stable partial nitrification in this study were: enrichment of AOB in the start-up period; controlled oxygen-limited conditions and the intermittent aeration strategy.

► Development of a novel technology for partial nitrification at ambient temperature. ► First time to use online NH4−–N measurement as a control parameter for bioreactors. ► RT-PCR analysis shows the population size of AOB was up to 10% of total bacteria. ► Intermittent aeration and oxygen-limited conditions sustained partial nitrification. ► The bioreactor recovered quickly after 47 days non-operation.

Keywords
Aeration control; Intermittent aeration; Nitrification; Nitrite accumulation; Molecular analysis; Online monitoring
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Long-term partial nitrification in an intermittently aerated sequencing batch reactor (SBR) treating ammonium-rich wastewater under controlled oxygen-limited conditions
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Publisher
Database: Elsevier - ScienceDirect
Journal: Biochemical Engineering Journal - Volume 55, Issue 3, 15 August 2011, Pages 215–222
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us