Tuesday March 8th, 2016 (By Mingming Li)
Today was the first lab rotation for this semester. The students were separated into two groups: ion exchange and disinfection. The ion exchange group did a batch reactor test and a column test for ammonia removal. Influent water used in this lab was synthetically made with ammonia to mimic the source water in Rwanda. 19 students participated in this experiment and formed sub groups for different tasks. Water samples were taken at designated times from the batch reactor and the column respectively. Samples were then processed in the following order by each subgroup: pH measurement, turbidity measurement, filtration, and dilution. The final step was to measure the ammonia concentration of treated water using a colorimeter. Students and TAs in the ion exchange team also brought music to the lab and created a great working environment.
The disinfection team focused on virus inactivation by chlorination. PRD1 bacteriophage was mixed with the synthetic water. Then chlorine was added to the reactor to inactivate the bacteriophage. Students took two sets of samples of the chlorine treated water at specific times: one for testing the PRD1 concentration and the other for testing chlorine decay over time. Students plated the treated water samples using agar overlay on petri-dishes to estimate the PRD1 bacteriophage concentration in the treated water.
This was a very fun lab. Students were able to have hands on experience of conducting experiments to test water quality. Doing lab experiments is a great way to help the students visualize and understand the knowledge they learn in class. Looking forward to the next lab rotation.