An aeration basin is filled to a volume of 425 m³with wastewater containing dissolved hydrogen sulfide (H₂S) of initial concentration 0.300 gmole/m³. The aeration basin is equipped with 10 gas spargers, with each injection nozzle located 3.2 m below the liquid surface. It is desired to remove the H₂S from the wastewater by a liquid-phase controlling inter phase mass-transfer stripping process, where the dis solved H₂S concentration will be reduced from 0.300 to 0.050 gmole/m³within a time of 150 min using air containing no H₂S as the aeration gas. The process temperature is maintained at 283 K. At 283 K, the Henry€™s law constant for H₂S dissolved in water is H = 367 atm (p_A= H · x^*_A),

the diffusion coefficient of H₂S in water is 1.4 × 10^-5 cm²/s, and diffusion coefficient of O₂ dissolved in water is 2.1 × 10^-5 cm²/s. 

a. Based on the desired process conditions, estimate the required k_L(A/V) for the H₂S inter phase mass-transfer process, and then scale this mass-transfer coefficient to k_L(A/V) for O₂ transfer using Penetration theory. 

b. Using the Eckenfelder plot, estimate the required aeration rate into each gas sparger for the required k_L(A/V) determined in part (a).

Transcribed Image Text:

0.180 0.020 0.140 0.100 0.120 0.108 0.160 XA 0.040 0.060 0.080 0.200 0.048 0.136 YA 0.004 0.013 0.027 0.080 0.125 0.145 0.152