ABSTRACT
Completely autotrophic nitrogen removal over nitrite (CANON) process was employed in an 18 L sequencing batch reactor (SBR) for treatment of optoelectronic industrial wastewater containing high strength ammonium nitrogen (3712 ± 120 mg NH4(+) - N L(-1)). About 89% of total nitrogen and 98% of NH4(+) - N removal efficiencies were observed at the loading rate of 909 g N m(-3) d(-1) and the HRT of 4 d. A profound variation in the performance of CANON process was experienced at high DO exposure (above 1 mg L(-1)) and high nitrite concentration (above 100 mg L(-1)). Inhibition due to high DO exposure was found to be reversible phenomenon whereas the synergistic inhibition of nitrite, free ammonia and free nitrous acid was irreversible. The fluctuation of reactor temperature between 17 and 37 °C did not affect the performance of CANON system. The CANON process was stably controlled at high nitrogen loading rate for more than one month. The co-existence of aerobic and anaerobic ammonium oxidizing bacteria in the reactor was detected by The PCR analysis. About 5 fold increase in amount of anammox bacteria over a period of 258 days was confirmed from the results of qPCR on day 487.
Subject(s)
Ammonia/metabolism , Electronics/methods , Industrial Waste/analysis , Nitrification , Optics and Photonics/methods , Wastewater/chemistry , Water Purification/methods , Alkalies/analysis , Anaerobiosis , Autotrophic Processes , Bacteria/metabolism , Bioreactors/microbiology , Hydrogen-Ion Concentration , Nitrates/analysis , Nitrites/analysis , Nitrogen/isolation & purification , Nitrous Acid/analysis , Oxidation-Reduction , Oxygen/analysis , Polymerase Chain Reaction , Temperature , Time Factors , Waste Disposal, Fluid , Water Pollutants, Chemical/isolation & purificationABSTRACT
Simultaneous partial nitrification, anaerobic ammonium oxidation and denitrification (SNAD) system was applied to treat the opto-electronic industrial wastewater in a 2.5L sequencing batch reactor. The characteristics of wastewater were low C/N ratio (≈ 0.2) with 100mg-COD/L and 567 mg NH(4)(+)-N/L. The experiment was carried out over 8 months in six different stages, where nitrogen loading rate was gradually increased from 16 g-N/m(3)d in stage I to 230 g-N/m(3)d in stage VI. The COD and nitrogen removal rates by the SNAD system reached to 28 g COD/m(3)d and 197 g NH(4)(+)-N/m(3)d, respectively in stage VI. These results showed that the SNAD system is suitable to treat wastewater containing high nitrogen pollutants with low COD level. Presence of ammonium oxidizing bacteria and anammox bacteria were confirmed by polymerase chain reaction (PCR). PCR results also indicated that Candidatus Kuenenia stuttgartiensis may be one of the dominant species in the reactor.
