Is it just me or has there been a lot of big words being thrown about lately? If you have been part of conversations that seem sesquipedalian in nature, you are not alone. I can recall a time when I used a word and when I was asked what it meant, I had to take pause. “I don’t know exactly,” I responded. I was tasked with explaining what a word meant that I had used. Another young colleague who was part of the conversation suggested we break the word up into its roots. I remembered learning that trick in high school English class and thought it was quite clever. His trick worked! He had used “etymology,” the study of where words come, to help me understand what I was talking about.
Many of us may have been attracted to engineering because of our less than stellar grasp of the English language. I myself am guilty of not always knowing what I am talking about. You know, that condition when your mouth moves faster than your brain sometimes? Just recently, another coworker was explaining a problem he was having with a rainwater harvesting system. The collected rainwater was being treated and used for water closet and urinal flushing. He explained the system was operating out of spec due to high turbidity.
“Did you take a look at the velocity through the pipe?” I asked him. My brain was equating high turbidity with turbulence caused by high velocity.
He paused for a moment and proceeded to explain to me the high turbidity was staining the fixtures and causing problems with the ultraviolet light treatment. He was being polite, which gave me just enough time to look up the definition of turbidity and do a little back peddling. The definition of turbidity turns out to be “a measure of the degree to which the water loses its transparency due to the presence of suspended particulates.” My inner voice wanted to say, “Yeah, I was just testing you,” but he and I both knew that I didn’t know what I was talking about.
The units used for the measure of turbidity is typically measured in nephelometric turbidity units (NTU), FAU (Formazin Attenuation Units) or FTU (Formazin Turbidity Units). An older unit of measure was the Jackson turbidity unit (JTU). I now know this.
Nephelometric units are scaled from 0 to 40 as outlined in the Environmental Protection Agencies (EPA) Method number 180.1: Determination of Turbidity by Nephelometry. It doesn’t say it in the document, but I would guess that mud has an NTU of 40. FAUs and FTUs have essentially the same as NTUs, but differ in how the instrument measures scattered light at 90 degrees from the light source. The light source could be white or infrared.
Jackson turbidity units are obtained by using something a little more rudimentary. I think they may have been invented by a group of friends who couldn’t get their hands on a nephelometer. The way to measure turbidity using JTUs is to put a candle under a graduated tube and fill it with the water being tested until you can’t make out the image of the candle anymore. JTUs are defined as “the inverse measure of the length of a column of water needed to completely obscure a candle flame viewed through it”. By all accounts, JTUs have been relinquished to obsolescence due to their subjective nature.
We all know how critical water quality is to public health. I can imagine a time when farmers or townsfolk would need a method to communicate how their water quality was, particularly to determine the presence of pathogens that might cause gastrointestinal disease. When you look at it that way, putting a candle under a graduated tube was quite clever.
I was a little hard on myself earlier for misunderstanding a word. I think I need to give myself a little credit, too. Even though turbidity and turbulence are two different concepts, they are tied together by the Latin root, “turb,” which means to stir up. The exact breakdown of turbidity includes the Latin root, “turba,” which means a crowd or disturbance. The breakdown of turbulent also translates to crowd and “full of commotion.” Either term is something we don’t want in our plumbing design, that’s for sure. Turbidity is a sign of unwanted particles, while turbulence is an indication of high velocity and can cause noise. Another interesting word that showed up in this article is nephelometry. Turns out that nephelometry comes the Greek root, “nephele,” which means cloudy.
We engineers may feel safe in our comfort zone of tables, system design and calculations, but every now and then we find ourselves challenged to put a sentence together. If you find yourself like me and stumble over a few words, take solace and keep educating yourself. I think a lot of scientific words are based on the classical languages, such as Latin and Greek so it doesn’t hurt to understand a little bit about how words are broken down. I really do appreciate my younger colleague reminding me of that trick called etymology.
There was a project manager we used to work with who would come over and frantically explain to us what we needed to do. After he would walk away, my boss would look at me and say, “Well that was clear as mud.” This would make me feel like I wasn’t the only one that didn’t understand what was going on. Next time you find yourself part of a turgid conversation, swollen with superfluous language or made cloudy by babble, just remember even the particles that cause turbidity can be filtered out; turbulent flow can be solved through sound design practice.