Week 6, Friday

Hello again,

A lot has happened this week! Yesterday, we took a field trip to the Scottsdale Water Campus. Arthur Nunez, the Water Reclamation Services Director, gave us a tour of and presentation on what is done there. The Scottsdale Water Campus treats wastewater from the city of Scottsdale and is recognized worldwide for its cutting-edge water treatment technologies. Most of the treated wastewater goes to 20-something privately owned golf courses. Some wastewater gets advanced treatment and is put back into the aquifer 500-600 feet underground. It takes about 12 years for the treated water to actually seep all the way down into the aquifer. This is called “indirect reuse” because one must wait until the water is put back into the aquifer to use it again.

Reverse osmosis room!

It’s prohibited to use treated wastewater for food agriculture or drinking water, even if it is treated to standards higher than that for bottled water. If I recall correctly, one of the reasons for this is the concern of not being able to effectively remove pharmaceuticals from the wastewater. Most of these drugs are rather new, so not much is known about them and it is uncertain the effect they would have if left in the treated water. California and Texas are the only states that do not have this prohibition. However, Arizona is beginning to consider lifting it as well. I forgot to ask why, but I can guess that it is because 1) our wastewater treatment technology is phenomenal, and 2) Arizona, much like TX and CA, has a very short water supply. The water campus was super neat. We even got to see into some of their labs (which were far cleaner than my own, lol)! I got to see in action a lot of the processes I’ve been learning about, such as reverse osmosis and ultrafiltration. I took quite a few pictures and have them dispersed throughout this post for you.

In other news, I’ve continued to take OCT images of the

A reverse osmosis module cut so we can see the cross section.

membranes started at 1.5X concentration, and Chay and I have also run 2 more 1.5X experiments. The first one was actually started at 2.46X, as Chay didn’t realize he was supposed to add much more DI than he did. That’s fine, however, because that run can be used to show that the flux decay isn’t dependent on concentration alone; time is also a factor. The second run this week yielded results that were a bit strange. I am usually the one who sets up the experiments, but Chay set up that run because I was running late that morning. It’s possible that his procedure differed from mine in some small way, and that had an effect on the results, which should have matched all of our other 1.5X runs.

Membrane filtration module.

That aside, yesterday afternoon I went to the shop and picked up the finished windowed cell! Today, I am planning on testing it out to see if our problem is fixed. Can’t wait!

We also took some SEM/EDS images of some membranes this week! So far, we’ve only done our control (membrane run with DI) and our most fouled membrane (started at 1.5X and run for ~40 hours, I believe). We also did a bit of mapping, and once we overlay the images with the maps, I’ll post some of them here! I believe we will be doing more SEM on Monday.

Electrolysis to prepare some of the cleaning agents.

We will also soon be running our membrane samples through the IC (ion chromatography) machine. Today, we have created 50mL stock solutions (1000ppm) for each ion that we want to analyze. I enjoyed doing the calculations for making these because it felt like I was finally getting to use all the knowledge I gained from my general chemistry courses. We will be using these solutions at different concentrations to create a calibration curve before we actually run our samples through. Once my mentor returns from the SEM (analyzing some of her own project’s data) in a bit, she will help Chay and I begin the IC calibration. I’m super excited because I got to see how the super cool IC worked during my first week here and haven’t yet gotten the chance to use it myself.

Chay sent me a copy of his abstract so that I could see how he formatted it. Francois is out of town again, but he is very good at checking his emails and responding quickly, so I’m hoping I can get some feedback from him on my abstract in time for Monday.

Hope all your projects are going well!

Sky