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Development and examination of a granular nitrogen-fixing wastewater treatment system

Paper ID Volume ID Publish Year Pages File Format Full-Text
35990 45117 2007 10 PDF Available
Title
Development and examination of a granular nitrogen-fixing wastewater treatment system
Abstract

This work presents the first success at aerobic granulation in a nitrogen deficient system. Two sequencing batch reactors (SBRs) were used to treat nitrogen deficient (the N-fix system) or nitrogen-sufficient (containing NH4Cl) synthetic wastewater (acetic acid as the sole carbon source). Granulation was observed in both systems, with particularly large granules (average diameter: 7 mm) grown in the N-fix system. We propose that the unique morphology of nitrogen-fixing granules is a consequence of the response of oxygen-sensitive diazotrophs to elevated oxygen concentrations.Both the nitrogen-fixing and nitrogen-supplemented systems were shown to be capable of removing all of the influent substrate carbon. Excellent biomass settleability characteristics were obtained, with the N-fix system having a final sludge volume index (SVI) of less than 100 mL g−1 and its granules having settling velocities of over 1.4 cm s−1. However, moderately high solids discharges were recorded for both systems, which revealed a potential limitation of granular sludge processes that is not widely discussed in the literature.

Keywords
Nitrogen fixation; Nitrogen deficient; Aerobic granules; Sludge settleability; Sequencing batch reactor
First Page Preview
Development and examination of a granular nitrogen-fixing wastewater treatment system
Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 42, Issue 5, May 2007, Pages 863–872
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering