EE Week 2 problems

Given: pw = 999 kg/m3 at 15oC and g = 9.81 m/s2

Problem 1

Determine the terminal settling velocity of a cryptosporidium oocyst having a diameter of 3 μm and a density of 1.05 g/cm3 in water at 15°C [μ=1.14x10-3 kg/(s•m)].

Problem 2

What percent of particles with diameter of 100 µm and a particle density of 2,650 kg/m3 are removed in a 2000 m3 rectangular sedimentation basin of that contains water at 10oC?

Assume the plant flow rate is 1.26x106 m3/day, µ = 1.307 x 10-3 kg/(s•m). List any other assumptions made in the calculation.

Problem 3

Design a rectangular sedimentation tank for a water treatment plant with flow rate of 1.26x106 m3/day where the requirement is that 99% percent of particles with diameter of 100 μm and a particle density of 2,050 kg/m3 must be removed. Assume water at 15 oC, µ = 1.307 x 10-3 kg/(s•m).