| Abstract |
| This research was aimed to investigate the performance of the bio film process with ceramic media for low organic and nitrogen levels in domestic wastewater effluent. It consisted of up flow anoxic (1.1㎥) and down flow oxic (0.9㎥) bio film reactors. Furthermore, we also evaluated the proper C/N ratio due to the lower denitrification efficiency without the addition of an external carbon source. The batch experiment suggested that the proper C/N ratio for enhancing denitrification and minimizing residual organic matter was 3.0 and it was applied to the anoxic biofilm reactor from phases Ⅱ to Ⅶ. The organic and nitrogen compounds in domestic wastewater effluent were very low and the C/N ratio of the influent in the biofilm process was 1.3. It was continuously operated for more than 180 days without pH adjustment and chemical addition except for methanol as an external carbon source. In this experiment, the hydraulic retention time (HRT) decreased from 5.3 to 1.0 hr. 10More than 75 and 83% of biochemical oxygen demand (BOD) and nitrate removal rates were obtained at a HRT of 5.3 hr, respectively. BOD and nitrate removal rates decreased to 53 and 58% as the HRT decreased to 1.0 hr. Although BOD and nitrate removal rates were reduced due to the decrease of the HRT, the effluent concentrations of BOD and nitrate in the biofilm process were less than 4mg/L. The specific denitrification rate increased as the HRT decreased. The maximum rate could be 1.97kg NO3?-N/㎥·d which was higher than values reported in the literature. Therefore the biofilm process could be effective for treating domestic wastewater effluent containing low concentrations of organic and nitrogen compounds. |
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| Key Words |
| Tertiary treatment, Biofilm process, Domestic wastewater effluent, C/N ratio, Specific denitrification |
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