Impact of the herbicide (RS)-MCPP on an anaerobic membrane bioreactor performance under different COD/nitrate ratios.
The degradation of (RS)-MCPP was investigated in an anaerobic membrane bioreactor (AnMBR) using nitrate as an available electron acceptor under different COD/NO(3)(-)-N ratios. Results showed high soluble COD removal efficiency (80-93%) when the reactor was operated at high COD/NO(3)(-)-N ratios. However, the COD removal started to decline (average 15%) at high nitrate concentrations coinciding with a drop in nitrate removal efficiency to 37%, suggesting that the denitrification activity dropped and affected the AnMBR performance when nitrate was the predominant electron acceptor. Additionally, the removal efficiency of (RS)-MCPP increased from 2% to 47% with reducing COD/NO(3)(-)-N ratios, whilst the (RS)-MCPP specific utilisation rate (SUR) was inversely proportional to the COD/NO(3)(-)-N ratio, suggesting that a lower COD/NO(3)(-)-N ratios had a positive influence on the (RS)-MCPP SUR. Although nitrate had a major impact on methane production rates, the methane composition was stable (approximately 80%) for COD/NO(3)(-)-N ratios of 23 or more.
Department of Environmental Engineering, Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Malaysia. muhdaliyuzir@utm.my
Ali
A
Yuzir
Shreeshivadasan
S
Chelliapan
Paul J
PJ
Sallis
D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000031:analogs & derivatives* / Q000302:isolation & purification; D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis / Q000295:instrumentation*; D019149:Bioreactors / Q000592:standards*; D005232:Fatty Acids, Volatile / Q000032:analysis; D006540:Herbicides / Q000302:isolation & purification*; D008567:Membranes, Artificial; D008697:Methane / Q000032:analysis; D009566:Nitrates / Q000032:analysis*
D005232:Fatty Acids, Volatile; D006540:Herbicides; D008567:Membranes, Artificial; D009566:Nitrates; C008340:mecoprop; D008456:2-Methyl-4-chlorophenoxyacetic Acid; D008697:Methane