| The effect of the ratio of height to diameter (H/D) on the process of simultaneous nitrogen removal from swine wastewater and hydrogen sulfide removal from biogas was investigated,using the bubble column reactors with packing material.The performance of the reactor with H/D of 8∶1, 3∶1 and 2∶1 was compared.Under temperature of 30-32℃,gas retention time of 6.70 min,hydraulic retention time of 3.35 d,hydrogen sulfide concentration of 1414-1838 mg·m-3 in biogas,and NO-x-N concentration of 114-243 mg·L-1 in influent.The reactor with H/D of 2∶1 achieved a stable and good treatment result,with the average removal rates of 96.7% for hydrogen sulfide,and 88.7% for NO-x-N.While the reactors with H/D of 3∶1 and 8∶1 obtained unstable and inferior results,with the average removal rates of 68.0%, 80.4% for hydrogen sulfide respectively,and 89.7%, 90.2% for NO-x-N respectively.The reason could be attributed to the following facts.The reactor with H/D of 2∶1 has a slower optimum gas velocity (3.12×10-2 m·s-1) than the reactor with H/D of 3∶1 and 8∶1 (3.62×10-2 m·s-1 and 6.64×10-2 m·s-1 respectively),and has a higher gas-liquid mass transfer coefficient (1.79×10-5 s-1) than the other two reactors (1.64×10-5 s-1 and 1.55×10-5 s-1 respectively).Results of the performance and the hydrodynamics parameters of the reactors all indicated that the reactor with H/D of 2∶1 was more suitable for the process of simultaneous nitrogen and hydrogen sulfide removal. |
