Week 13: November 26, 2023

November 26, 2023

Greetings on a cloudy and snowy Sunday!

I hope you all had a lovely Thanksgiving and you have a safe and uneventful journey back to campus today. Be careful driving as it is pretty slick!

Schedule for this week's lecture and tutorial:

Monday: Work session for adsorption homework and MD2
Tuesday: Work session for MD2 or Tutorial 3. If you wish to work in the lab, you must sign up. You may also sign up for Thursday morning. Any other times must be arranged with Joseph.
Wednesday: Residual Management
Friday: Residual Management

I recognize that many of you are also in CE 495 and capstone project reports are due on Tuesday. Given that, if you wish to have until Thursday at 11:59 PM to turn in your MD2 projects, just let me know. I cannot give extensions beyond that, as we need time to grade the reports and get them back to you.

The graders and I are working to complete all homework grading this week. I graded the field trip reports and the disinfection homework over break, so you should see those grades in LON-CAPA.

The other two assignments that are outstanding are:

Tutorial 3: Water Treatment Plant Demonstration Due Dec. 1 (Absolute deadline Dec. 6th, no extensions beyond the 6th)
Tutorial 4: Premise Plumbing Due Dec. 8th. (This is to be done individually. You may choose to not do this assignment and I will then redistribute the 160 points for tutorials to the three tutorial assignments. If you choose this option, you must upload a note stating such on the Tutorial 4 dropbox.)

I have also posted MiniDesign3 specifications. It is due December 15th at 11:59 PM. There will be no grace periods given for this assignment as we need the time to grade the reports and submit grades by December 19th at 4 PM.

I have had several questions about MD2 and am providing clarification below:

Question about flocculation:

The values of 130-300 s^-1 are from Table 6-6 in the textbook. However, if you use the GT values in the same table with typical detention times (as given in the MD2 guidelines), the GT value will be greatly exceeded. Given that you may reduce the G value, as long as you ensure that the GT values are within the range given in Table 6-6 for softening (use 10% solids). In this way you can ensure that the peripheral speed of the outside blade is <1 m/s.

Question about softening:

The concentrations of suspended solids, calcium, magnesium, and alkalinity are given in the water quality data provided with MD1. You need to calculate the concentrations for the stated blend of river water and groundwater.

Question about sludge production:

There are two sources of sludge: softening reactions and suspended solids removal. You can determine the suspended solids removal based from Type 2 settling curve. Use the detention time and water column depth from your sedimentation basin design to determine the percent removal of suspended solids. You can determine the amount of softening sludge from the softening reactions. You should treat to the stoichiometric limits. If you wish, you can blend in untreated groundwater to achieve a hardness of 100-130 mg/L as CaCO3.

And a few photos from walks over the break. No, I didn't get to Lake Michigan but I did get in several good walks and even gave my friend Maureen a tour of the EL WRRF outfall as seen from the River Trail.