need help with CHEM homework

Homework 3 CE2633 –Environmental Engineering

Due Date: 10/08/2014 Problem 1 (2.5 points) A lake is contaminated by a LUST (Leak Underground Storage Tank) releasing BETX slowly into the lake at a rate of 250 g/day for several years. A stream entering and existing the lake with a flow rate of 100 m3/day. Assuming there is no other sources of BTEX leak besides the LUST and there is no background BTEX in the lake before the leak started. The volume of the lake is 1000 m3.

a) What is the concentration of BTEX in the lake as a function of time? Please draw

a graph using excel to show the result. b) When does the BTEX concentration in the reservoir reach 95% of its final value? c) Will the concentration of BTEX in the lake reach steady state given unlimited

time? Problem 2 (2.5 points) A baghouse is being used to remove dust from an air exhaust stream flowing at 100 m3/min. The dirty air contains 10.0 g/m3 of particles, and the cleaned air from the baghouse contains 0.9 g/m3. (This problem is not the same as the class example, actually a lot simpler)

a) What is the mass of dust collected per day (in kg)? Problem 3 (2.5 points) Text book questions 4-24 Problem 4 (2.5 points) Text book question 4-32 Attention: CMFR = CSTR , same model, different name, CSTR is commonly used in engineering world, especially in your future FE exam. Text book uses CMFR.