A sewage lift station has tank (3000 L) that is stagnant for 8 h during low flows each night. The sewage contains 10 mg/L SO42--S. Sulfate (SO42-) is converted to sulfide (S2-), which is then converted to toxic H2S gas. The reaction rate of sulfate-sulfur to sulfide-sulfur can be described by a second order decay, k = 0.01 L/(mg∙h). How long (h) will it take for half of the sulfate-sulfur in the lift station to be converted to sulfide-sulfur?
for second order reaction, T= CAOXA/-rA
-rA= KCA2= KCAO2*(1-XA)2=
T= CAOXA/KCAO2*(1-XA)2=
K is the rate constant = 0.01 L/mg.h
XA=0.5 , CAO=10mg/L
T= (XA/(1-XA)2 * 1/KCAO = (0.5/0.25)*(1/0.01*10)= 2 hrs
the time taken = 2 hrs
A sewage lift station has tank (3000 L) that is stagnant for 8 h during low...
10. Write a one-page summary of the attached paper? INTRODUCTION Many problems can develop in activated sludge operation that adversely affect effluent quality with origins in the engineering, hydraulic and microbiological components of the process. The real "heart" of the activated sludge system is the development and maintenance of a mixed microbial culture (activated sludge) that treats wastewater and which can be managed. One definition of a wastewater treatment plant operator is a "bug farmer", one who controls the aeration...