| Title |
Effect of HRT and Internal Recycle Ratio on Removal of Organic and Nitrogen in Swine Wastewater by Anoxic-Oxic Process Combined with Membrane |
| Authors |
황규대 ( Gye Dae Whang ) ; 이봉희 ( Bong Hee Lee ) ; 이현덕 ( Hyun Duk Lee ) |
| Keywords |
Anoxic;oxic process; HRT; Internal recycle ratio |
| Abstract |
The objective of this study was to determine the optimal operation conditions in an anoxic·oxic process to eliminate both organic and nitrogen matters in swine wastewater. For the purpose of this, the removal efficiency was evaluated with various HRTs and internal recycling ratio. During the whole 580 days of experiment, HRTs had been gradually decreased in an order of 20, 14, 12 and l0days, and the internal recycle ratio was kept at 20Q. So as to determine the effect of the internal recycle ratio on the nitrogen removal, the internal recycle ratio had been gradually increased from 20Q to 50Q while HRT was maintained at 12days. As a result, it was shown that the removal efficiency of organic matter was above 95% regardless of changing of HRTs. The average influent concentration of TCODcr and SCODcr were 24,854 ㎎/L and 18,920 ㎎/L, respectively. Average removal efficiency of TKN was shown to be nearly 98% when HRT was kept at 12days; however, the NH₄^+-N concentration of effluent was shown to be increased when the loading rate of NH₄^+-N was increased to 0.602 kgNH₄^+-N/m³-day by means of decreasing HRT to 10days. It was concluded that nitrogen loading rates should be more considered rather than organic loading rates in case of determining an optimal HRT. When gradually increasing the internal recycle ratio from 20Q to 50Q, the removal efficiency of organic matters and TKN were 96% and 98%, respectively so that no significant changes in removal efficiency was detected. However, when the internal recycle ratio was kept at 50Q, it was revealed that the NO₃-N concentration of effluent seemed to drop and the average NO₃-N concentration of effluent was around 52 ㎎/L. |