Feasibility of Biological Elimination of COD, Ammonia-Nitrogen and Total Nitrogen from HTS Molecular Sieves Wastewater Using SBR Processes

Abstract

The wastewater from hollow titanium silicate (HTS) zeolite consists essentially of high concentrations of COD and salt, and low ammonia-nitrogen concentrations (or high, sometimes). These chemical pollutants are produced in very large quantities during oil refining and are very difficult to manage on site. In addition, they can be very harmful to the environment when released without any treatment. The aim of this study is to evaluate, on the one hand, the feasibility of removing the COD from HTS wastewater using a sequencing batch reactor (SBR) and, on the other hand, to test the combined effect of nitrification and denitrification under different conditions of treatment on the elimination of Total Nitrogen (TN) from HTS wastewater containing a high concentration of ammonia-nitrogen. SBR intermittent domestication tests of sludge have been successfully carried out with wastewater from a municipal treatment plant with a COD removal rate of 87%. Subsequently, HTS wastewater containing high concentrations of COD was treated by this SBR system. After three months of operation, the efficiency of COD elimination fluctuated between 47% and 67%. Therefore this result could serve as a precursor to a possible second COD bioprocessing. The results obtained during nitrification of the same HTS molecular sieves wastewater with low C/N ratio gave, under an operating temperature below 10˚C (winter conditions), less than 16% of total nitrogen (TN) removal. When the temperature was increased to 40˚C, the TN removal efficiency remained worse.

Effects of Coagulation and Ozonation Pretreatments on Biochemical Treatment of Fluid Catalytic Cracking Wastewater

“…However, the resulted COD removal rates were 83% and 76%, respectively, indicating that the microorganisms were still active, so operation can be continued to acclimate and to evaluate the denitrification effect on the system. The result shows that the sludge acclimated by SBR process [28] was more efficient than that one prepared by the A/O process so that it was chosen for this A/O process. However, the removal rate of ammonia-N has not yet been improved.…”