The earthquake!

Name: Cheryl St. Amant
Age:
52
Job Title: Associate General Manager Operations
Employer: Fauquier County Water and Sanitation Authority
University: George Washington University – Masters of Engineering Administration
The Catholic University of America – Bachelors of Science Civil Engineering
Lives: Virginia, United States

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What was the first thing you did today? Did you hop in the shower, brush your teeth, or go to the bathroom? Have you ever wondered how the water got to your tap or what happened after you flushed the toilet?

That’s where I come in. Welcome to my world – The World of Water! I am a civil engineer and I work for a company that provides drinking water and treats the waste water.
 

The earthquake

Today I am going to tell you about an interesting project that I worked on as a result of an earthquake and how the combination of science, technology, engineering and maths careers helped to find and solve the problem.

Let’s get to the facts! On August 23, 2011, a 5.8 magnitude earthquake in Virginia caused ground shaking up and down the eastern United States.

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Virginia 5.8 Magnitude Earthquake Impact


The water company that I work for is located about 60 miles north of the epicenter. The shaking intensity, as can be seen below, was considered to be moderate with the potential for light damage.

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Water company response
A damage assessment of the water and wastewater facilities indicated that the earthquake appeared not to have caused any problems. No buildings fell down and there were no pipes broken with water shooting into the air.

What wasn’t apparent at the time was the “internal” damage to our underground water systems. We had no way of seeing the damage until science and engineering stepped in to tell us!


Water damage and engineers

The day after the earthquake the Water Department conducted its annual water quality test and found E. Coli (Escherichia coli) bacteria in one out of three wells supplying drinking water to a community. This bacteria can sometimes make humans very sick. Science is telling us that there is a problem: somehow bacteria are getting into the water that is deep underground. How could this happen? This is where engineers come in to search for the cause of the problem.

A TV camera was put into the well so that the engineers could look for damage. The video revealed two problems; 1) the sanitary seal was damaged and 2) the earthquake had permanently changed the earth below, creating pathways for bacteria to enter the water. We had a problem and a cause for groundwater bacteria; now engineers must now figure out a solution.

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Engineering a solution

The solution ended up being not so easy! First, we tried to “slip line” the well by inserting a smaller pipe inside the well. This would seal off the pathways for the bacteria to get into the water. This repair method failed and the bacteria still found a path into the groundwater.
 

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Slip lining the well

The engineers went back to the drawing board and began considering other alternatives. Should they drill another well and risk the same problem occurring or install a treatment system to remove the bacteria? The problem was complex and many issues had to be considered by the engineers such as cost, reliability and sustainability: is this a solution that will last?

The engineers recommended installing a microfilter system to remove the bacteria and other contaminants in the groundwater. This solution eliminated the problem, not just for this one well, but would treat all the wells in this community and allow for future growth.

The microfilter is very cool technology. Here’s a picture of one filter fiber compared to a regular pencil. Along this fiber are tiny small holes that will filter out the bacteria.

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Filter Fiber

Water is forced to go through the small holes and the bacteria are too big to fit through the holes and get stuck on the outside of the filter fiber while the clean water goes into the hollow fiber and out the top.


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Thousands of these fibers are put into a tube which creates the microfilter system shown below.

Blogs/Cheryl St Amant/microfilter-2-761.jpg (761 x 398)This is unbelievable technology that was first used in the medical field for blood filtration. It was incredibly successful and now the technology is used in the environmental field of water.

 

Science, technology, engineering and maths careers
The earthquake, the impact on the water system, and the solutions are a perfect example of how different careers come together to solve a problem. Science and the lab biologist/chemists told us there was a problem through their bacteria tests. Technology helped to solve the problem. Engineers, like me, were the bridge between science and technology to help develop the solutions to resolve the problem. Together, these careers help solve the most challenging problems that affect our everyday lives to provide our most basic needs - water.


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Pictures courtesy of:
1. Virginia earthquake 2011 - Google Search. (n.d.). Retrieved July 8, 2015.
2. USGS, M5.8 – Virginia. (n.d.). Retrieved July 7, 2015.
3. Emery & Garrett Earthquake Damage Report, April 2012
4. Pall microfilter presentation, July 18, 2012