Microbial community analysis in the autotrophic denitrification process using spent sulfidic caustic by denaturing gradient gel electrophoresis of PCR-amplified genes

摘要

Spent sulfidic caustic (SSC) produced from petrochemical plants contains a high concentration ofnhydrogen sulfide and alkalinity, and some almost non-biodegradable organic compounds such asnbenzene, toluene, ethylbenzene and xylenes (BTEX). SSC is mainly incinerated with auxiliary fuel,nleading to secondary pollution problems. The reuse of this waste is becoming increasinglynimportant from economic and environmental viewpoints. To denitrify wastewater with low COD/Nnratio, additional carbon sources are required. Thus, autotrophic denitrification has attractednincreasing attention. In this study, SSC was injected as an electron donor for sulfur-basednautotrophic denitrification in the modified Ludzack-Ettinger (MLE) process. The efficiencies ofnnitrification, COD, and total nitrogen (TN) removal were evaluated with varying SSC dosage.nAdequate SSC injection exhibited stable autotrophic denitrification. No BTEX were detected in thenmonitored BTEX concentrations of the effluent. To analyse the microbial community of the MLEnprocess, PCR-DGGE based on 16 S rDNA with EUB primers, TD primers and nirK gene with nirKnprimers was performed in order to elucidate the application of the MLE process to SSC.