Iranian Journal of

Background & Objectives: Excessive discharge of hazardous materials such as nitrogenous and organic compounds into the environment has negative impacts on the health of the aquatic environment. The main objective of this research was focused on evaluating the feasibility of using modified SBR reactor for the removal of nitrogenous compounds and chemical oxygen demand (COD). Materials & Methods: The experiments were performed using an up-flow continuous reactor with intermittent effluent. At first, four different cycles including aeration, settling, and decant (3, 4, 6, and 8 h) were designed for the performance of the reactor. Then, the efficiency of each cycle was determined for different concentrations of COD (250-1500 mg/L) and ammonia (40-100 mg/L). Results: Data demonstrated that all cycles had very good performances for the removal of COD. The average COD removal efficiencies of phases 1 through 4 were 91.7, 91.5, 92, and 92.7% respectively. The average NH^₄₊ removal efficiencies of phase 3 and 4 were 92.7 and 95.8% respectively. Conclusion: The performance of phase 4 (with the cycle of 8 h) for the removal of nitrogen compound and COD was particularly high. The combination of anoxic and aerobic cycles in the reactor and providing nitrate as an electron receptor had the best performance for the removal of nitrogen from wastewater. Therefore, the continuous up-flow reactor was a good alternative to batch reactor in removing nitrogen compound and COD simultaneously.

Background and Objectives: Phenol is one of the industrial pollutants in wastewaters, which due to its toxicity for biological systems various pretreatment processes have been used for its detoxification. In this study, the combination of catalytic ozonation process (COP) and sequencing batch reactor (SBR) were used for detoxification of these types of wastewaters.

Materials and Methodology: In this study, the effect of COP on phenol degradation, COD removal, and detoxification of wastewater was investigated. To determine the acute toxicity of effluents and identification of intermediate compounds produced in COP, bioassay using Daphnia Magna and GC / MS were used, respectively. Then, phenol and COD removal of pretreated wastewater was investigated in SBR.

Results: It was found that under optimal conditions in COP (time = 60 min), the concentrations of phenol and COD reduced from 500 and 1162 to 7.5 and 351 mg/L respectively and pretreated effluent toxicity (TU = 36), after rising in the initial stage of reaction, effectively reduced at the end of process (TU=2.3). the integration of this process with SBR could decreased the COD and phenol concentration less than the detectable range by HPLC. 

Conclusion: Results showed that COP has a high effect on biodegradability, detoxification, and mineralization of phenol and combination of COP with SBR process can effectively treat wastewaters containing phenol.