Monday, March 27, 2017

Chapter Six: And You Thought Dinosaurs Went Extinct (feat. Melanie, Jeff, Jamie, Bryden, Sabrina)

Do you obsess over dinosaurs? I know plenty of people that went crazy over the Jurassic Park series, especially Jurassic World, to the point of religiously playing that Jurassic World iPhone game. But me? I never got into it. Even then, you can probably imagine how surprised I was to walk into the lab and find a real-life dinosaur this morning. Guess what type of dinosaur it was? T-rex? Nope. Stegosaurus? Try again! I don't know any other dinosaurs... I give up. Good choice, because on the path you were on, you never would have guessed.

I walked into the lab this morning and found Windows 3.1 running on a computer that's older than me. I mean, honestly, I was so surprised, because this computer was so far in the past. It was doing a really convincing Bayer impression. Like, this computer was really, really old.

On a serious note, I did a bit more of the same in the lab this past week, not including an incredibly cool development in my water research. Besides creating a couple new standardized trays, I washed and sorted some trays so that they could be available for use. This entailed me grabbing some thick gloves, mixing a tiny bit of potent cleaner into a ton of tap water, and scrubbing like mad.

The trays start out in a bucket, with all the tape ripped off and thrown away.

The trays get dipped into the bottom tub, which is full of soapy water, get scrubbed, and then get transferred to the top tub, which is full of regular tap water.

The fun part of the process: to wash the soapy/tap water out of the trays, we use an eyewash. It hooks up to tap water, but it outputs pressurized water, pushing all of the gunk out of the tray.

Lastly, we run the trays under distilled water.
After that, we put the trays in the "oven," which is pretty much just a heated cabinet for drying materials in the lab. After they've dried, we match the trays back with their lids (which is a bit of a puzzle, given that there are at least 20 trays and lids to match up).

Now for the cool stuff. I got to work with Jeff and Bryden on analyzing water samples today (including my own!), meaning I got to work with an ion chromatography machine. Essentially, ion chromatography is like a mass spectrometer for water: different known concentrations of common ions in water (chlorine, nitrate, phosphate, and sulfate) are put through the ion chromatography machine, and, because they are different sizes, they move through the machine at different speeds. When an ion reaches the end of the machine, where the reading is taken, it causes resistance (the more resistance, the more of the material). After we run standardized concentrations of these ions through the machine, we create a calibration curve for water samples, with concentration of the ion on the y-axis and resistance on the x-axis. With this curve, we can run any water sample through the machine and compare the resulting resistance to the curve, giving us the concentration of particular ions.
The calibration flasks, full of concentrations of chlorine, nitrate, phosphate, sulfate, and water.

The samples get run through that ion chromatography machine on the left, and the readings come out on that computer on the right...

And because the ion chromatography machine in the lab is over 20 years old, it can only communicate with an older computer, like this fossil right here.

The readings will come out in little spikes, with chlorine coming out first, followed by nitrate, then phosphate, and finally sulfate. This isn't the final calibration graph: it's a graph of resistance versus time so that we can distinguish between ions.

To measure the amounts, we record the area under that graph.
And that's the extent of what I did in the lab this past week. In the upcoming week, I'll do some more cool things with water samples!

Regarding my water research project, the extra research I've done on Reverse Osmosis makes it nonviable for potable water treatment because it demineralizes the water, resulting in aggressive water that leeches metals from pipes and takes in contaminants (Pelican Water Systems). Further, such demineralized water reduces nutrient intake necessary for healthy humans (WHO). While it is possible to stabilize the water with calcium and magnesium and add in minerals later, it's simply not worth it to take out the minerals just to add them back in again, especially when the harmful minerals that you're taking out are in such low quantities, as they are in Lake Mary. Thus, sand/andesite filtration is the right way to go, based on a cost-benefit analysis.

Further, I've finally been able to run some simple statistical analysis of Lake Mary's water from 2000-2015 by averaging out the HAA5 and TTHM levels and finding out the probability of an EPA violation in DBPs. Here's the excel chart that I compiled the data in (including other contaminants and aspects of water quality):


The results of our water treatment have proven that the only part of the treatment process that needs to be evaluated is the chemical treatment, evident by the EPA violation in 2015-2016. It is notable that levels of lead in 2014-2015 nearly reached the action level, but fixing this (when an action level violation hasn't occurred yet in the many years that Flagstaff has monitored their water for lead) simply wouldn't be feasible, as it would require sampling of hundreds of taps around Flagstaff to first identify where lead levels are dangerous, as well as an actual re-piping of said taps.

Through a graphing of the data, both HAA5 and TTHM are relatively normal, allowing for a simple analysis of the data:

Slight right skewness, but relatively normal.


Slight left skewness, but relatively normal.
By assuming relative normality and assuming that these sixteen years are representative of the future's years, we can find the probability of an EPA violation by using the mean and the standard deviation of the samples.

HAA5 (MCL=60 ppb): x̅=38.77285714 ppb, Sx=15.34952288 ppb
P(HAA5>60) = normalcdf(60,1000,38.77285714,15.34952288) = 0.0833449467 ≈ 8.33%

TTHM (MCL=80 ppb): x̅=40.845 ppb, Sx=16.88553227 ppb
P(TTHM>80) = normalcdf(80,1000,40.845,16.88553227) = 0.0102015871 ≈ 1.02%

With these values now on hand, we can compare them to our 5% benchmark, and we can find that it is likely that HAA5 will have an EPA violation if we were to switch back to chlorine gas treatment, given that environmental conditions are the same. Thus, it is optimal for Flagstaff to continue on with its chlorine dioxide treatment from a purely water-quality standpoint.

From a budgetary standpoint, it's completely viable to use chlorine dioxide year-round, even as it increases the amount of money spent on water by $25,000 annually, because we already cut out hundreds of thousands of dollars spent on water and wastewater treatment from the utilities department: in 2014-2015, we spent about $490k on treating potable water; in 2015-2016, we reduced the budgetary allocation to $435k. With that difference, there's no issue with a $25,000 increase per year, as we've already spent that much in the past. Even further, 2014-2015 suggests that there will be leftover money to be allocated in the Utilities Department: while the 2014-2015 budget allocated $5.06M to Water Production section of the Utilities Department, only about $4.18M was actual expended.

With each of these in mind, it is completely viable for the Lake Mary Water Treatment Plant to continue its current treatment procedures. However, this isn't to say that we can't improve: some day, we hope to be using nanomembranes instead of sand/andesite filtration simply because it filters out everything except for the dissolved solids (minerals), which are good, as seen by the information on reverse osmosis. There may be better coagulants available (as seen by this study), and the hope is that they'll be made more widely available in the future. And optimization of the flow of water, of our pipes, and every aspect of the treatment process can be made as new issues arise. But for now, Flagstaff is looking pretty good.

From here on out, this blog will be documenting my internship! Thanks for being interested, and here's to the next month!

End of Chapter Six.

4 comments:

  1. First, thanks for the info regarding Reverse Osmosis. Second, I was expecting to see a conclusion so soon! Have you shared this with Steve Camp?

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  2. 7/10 for the roast on Bayer. That equipment you described that measures the resistance at a certain time is very interesting. Is it only used for water analysis like you're doing or does it have other applications?

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    1. I'll take a 70%. Not my best roast ever on him lol. And I think it can measure the isotope concentration of any liquid, though generally, it just runs water samples.

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