In the petrochemical industrial park various manufacturers` effluent contributed to quite different ingredient characteristic of wastewater. For example the organic nitrogenous chelating agent (EDTA) as well as the ammonia nitrogen constituted TKN as the critical pollutants to the biological treatment process with limited nitrification performance. In DS petrochemical industrial wastewater treatment plant, a series of activated carbon plus activated sludge basins were operated as PACT process. The organic carbon (COD=300 mg/L) was adsorbed onto the PAC, while the nitrogenous pollutants (TKN=350 mg/L) could not be biodegraded effectively without anoxic microbes. So that in the PACT process the activated carbon loading capacity was somewhat low, the adhesive` biofilm thickness was too thin, and the aeration performance was insufficient to promote the biotreatment efficiency with simultaneous COD degradation and ammonium nitrification. In the last decade, some new biological nitrogen removal processes have been developed to reduce operational costs of aerobic nitrification and organic carbon source supplement for heterotrophic denitrification. Many studies focused on the development of autotrophic nitrogen elimination technology such as process combination of partial nitrification and the anammox process, which is regarded as a promising new method for removing nitrogen from wastewater with a low C/N ratio(<0.15) and a fairly large quantity of ammonium. In this study, a combined bioprocess of partial nitrification (MBBR) and anammox (BioWEB) chambers was developed to achieve a syntrophic microenvironment wherein only the influent ammonium was converted to nitrite, followed by the anammox process to ensure total nitrogen removal, simultaneously to 70% . The return activated sludge collected from DS petrochemical industry wastewater treatment was used as seeding inoculation into the laboratory scale biofilm reactor. In addition, a molecular biomonitoring technology (T-RFLP and cloning) was applied to identify the bacterial community shift of the biofilm and the acclimated biomass within 260 days of the continuous-flow operation. Simultaneous denitrification of nitrite with ammonium as the electron donor to yield nitrogen gas was observed while the rows formed nitrite is reduced faster than ammonium oxidation with limited aeration . The continuous operation results showed that the maximum anammox reaction rate occurred when the DO ranging from 0.8 mg/L to 1.0 mg/L. In the lab-scale bioreactor of 10L working volume, the 16SrDNA clone library and DNA sequencing , were conducted to discover the microbial community with of 31 OTUs 98 clones (operational taxonomic units) that indicated high biodiversity of microbial population was present in the oxic-anoxic chamber . The detectable bacteria simultaneously represent AOB and NOB. The primary species of ammonia oxidizing bacteria, AOB was identified as Nitrosomonas sp. while the major nitrite oxidizing bacteria, NOB was Nitrospira sp. of that contributed to the main microorganism bacteria colony. The result of T-RFLP analysis the microbial similarity.

MBBR,TN, Nitrite, anammox