[Effects of carbon sources changes on the property and morphology of 2,4-D degraded aerobic sludge granules].
This study investigated the changes of the morphology, structure, and capability of removing the target contamination of the aerobic granules pre-cultured with mixed substrates of glucose and 2,4-dichlorophenoxyacetic acid (2,4-D) in a long-time running sequence batch reactor (SBR), when the carbon source transformed into the sole carbon source of 2,4-D. Results showed that when the substrate turned to the sole carbon source of 2,4-D, the aerobic granules still maintained a strong degradation ability to the target contamination; a 2,4-D removal percentage of 99.2% -100% and an average COD removal rate of 85.6% were achieved at the initial 2,4-D concentration of 361-564 mg/L. Carbon source transformation caused certain damages to the original aerobic granule structure, made some parts of granules disintegrated, and led to granule size decline from 513 microm to 302 microm. However, those granules maintained the main body, re-aggregated and grew after a period of adaptation due to their strong resistance to toxicity. Aerobic granules capable of utilizing 2,4-D as the sole carbon source with a good settling ability (SYI 20-40 mL/g) and a mean diameter of 489 microm were finally obtained in this study. Scanning electron microscope (SEM) observation showed that the diversity of granule microbial species was declined when turned to the sole carbon source.
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China. majingyun8996@126.com
Jing-Yun
JY
Ma
Xian-Chun
XC
Quan
Wei-Cong
WC
Xiong
D015084:2,4-Dichlorophenoxyacetic Acid / Q000737:chemistry / Q000302:isolation & purification*; D000332:Aerobiosis; D001673:Biodegradation, Environmental; D019149:Bioreactors; D002244:Carbon / Q000737:chemistry*; D004785:Environmental Pollutants / Q000737:chemistry / Q000302:isolation & purification*; D005947:Glucose / Q000737:chemistry; D010316:Particle Size; D012722:Sewage / Q000737:chemistry*
D004785:Environmental Pollutants; D012722:Sewage; D015084:2,4-Dichlorophenoxyacetic Acid; D002244:Carbon; D005947:Glucose