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Aerobic Granular Sludge for Dye Biodegradation in a Sequencing Batch Reactor With Anaerobic/Aerobic Cycles
Author(s) -
Sadri Moghaddam Shabnam,
Alavi Moghaddam Mohammad Reza
Publication year - 2016
Publication title -
clean – soil, air, water
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 66
eISSN - 1863-0669
pISSN - 1863-0650
DOI - 10.1002/clen.201400855
Subject(s) - biodegradation , anaerobic exercise , sequencing batch reactor , granule (geology) , chemistry , extracellular polymeric substance , bioreactor , microorganism , volatile suspended solids , wastewater , pulp and paper industry , chemical engineering , chromatography , chemical oxygen demand , bacteria , waste management , organic chemistry , biofilm , materials science , biology , physiology , genetics , engineering , composite material
This study investigated the formation of aerobic granular sludge with the main objective of Acid Red 18 (AR18) biodegradation in an altering anaerobic–aerobic sequencing batch reactor. According to the obtained results, the cultivated granules showed a stable structure in the treatment of synthetic wastewater containing 50 mg/L AR18, while no considerable variety in their characteristics and no granule break up were observed. As reported by many researchers, decolourization of AR18 is due to the anaerobic biodegradation of the azo bond; however, monitoring of the dye biodegradation through UV‐Vis spectroscopy showed that the contribution of the aerobic phase in dye removal was significant. This indicates the penetration of AR18 into the inner layers of granules and the ability of anaerobic microorganisms within the granules to degrade the dye through the consumption of tightly bound extracellular polymeric substances (EPS) as a carbon and energy source. The aerobic granules were not able to decompose anaerobically formed AR18 intermediates under aerobic conditions. The increase of the initial dye concentration from 50 to 100 mg/L caused the production of excess loosely bound EPS, which led to instability of the granules and hampered the dye removal efficiency.