Denitrifying bacteria are immobilised in gel beads and used in a stirred reactor for removal of nitrate from groundwater. At a nitrate concentration of 3 g m-3, the conversion rate is 0.011 g s-1 m-3 catalyst. The effective diffusivity of nitrate in the gel is 1.5×10-9 m2 s-1, the beads are 6 mm in diameter, and the liquid-solid mass-transfer coefficient is 10-5 m s-1. Km for the immobilised bacteria is approximately 25 g m-3. What is the value of an observable modulus for external mass transfer, Ω?

Denitrifying bacteria are immobilised in gel beads and used in a stir

1.	Denitrifying bacteria are immobilised in gel beads and used in a stirred reactor for removal of nitrate from groundwater. At a nitrate concentration of 3 g m-3, the conversion rate is 0.011 g s-1 m-3 catalyst. The effective diffusivity of nitrate in the gel is 1.5×10-9 m2 s-1, the beads are 6 mm in diameter, and the liquid-solid mass-transfer coefficient is 10-5 m s-1. Km for the immobilised bacteria is approximately 25 g m-3. What is the value of an observable modulus for external mass transfer, Ω?
A.	0.35
B.	0.36
C.	0.37
D.	0.38
Answer» D. 0.38