Cool, Clear Water

Posted Tuesday, September 16, 2014 at 1:36 PM

"The next person who delivers a cool, clear glass of water to you may be a civil or chemical engineer."

Engineering Careers
Chemical | Civil |

Cool, Clear Water

PostedTuesday, September 16, 2014 at 2:11 PM

Alice Wu
Alice Wu
Cool, Clear Water

Photo by OlkaCF, via

Author: Alice Wu

The next person who delivers a cool, clear glass of water to you may be a civil or chemical engineer. Taking a shower, brushing your teeth, watering your garden, or diving into a local swimming pool all require one thing: clean water, and now, thanks to engineers, the precious resource is more available, even during drought years. 

Seven western and central states are currently in the third year of one of the most severe droughts in history, including California, Oregon, Nevada, Arizona, New Mexico, Texas and Oklahoma. California faces the most urgent water crisis. With waterways and reservoirs quickly drying up and no signs of rain, communities are desperate to find new and efficient ways to conserve water. Fortunately, the Santa Clara Valley Water District, in partnership with the cities of San Jose and Santa Clara, has introduced a new water purification plant, the Silicon Valley Advanced Water Purification Center, which uses state-of-the-art chemical engineering to produce clean, recycled water.

Recycled water was introduced in the early 1900s for irrigation, but Silicon Valley’s new Water Purification Center takes water reclamation into the 21st century. The system purifies water so well that the recycled water can be used for many future uses, including drinking supplies. After water has already undergone two levels of typical wastewater treatment, the new facility uses new, innovative technology to perform three additional processes: microfiltration, reverse osmosis, and ultraviolet light.

First, water is pumped through racks of filtration modules, each comprised of thousands of hollow fibers with pores that are five hundred times smaller than the width of a human hair. As the water flows into the center of the fibers, the pores filter out microscopic particles such as silt, protozoan cists, bacteria, and viruses. The filtration modules are regularly backwashed to prevent buildup of particles; this helps the plant recover a higher amount of pure water.

Water Purification Process

Then, the newly micro filtered water is treated with reverse osmosis. Water is forced through special, plastic membrane sheet to remove compounds such as salt, organic compounds, microorganisms, and more viruses. Rolls of membrane sheets are tightly wound into cylinder-shaped vessels, which allow water to flood through the sheets easily, while filtering out contaminants. Pure infused water flows out of the cylindrical tubes into the next process, while substance-riddled concentrate water (dirty water) flows into another outlet for disposal

As a last safety precaution, the water is disinfected using ultraviolet (UV) light; this process is similar to the one used to sterilize medical and dental instruments. Six UV trains, each equipped with a pair of UV vessels, train forty high-intensity UV lamp bulbs on the water to remove any last trace of organic molecules.

One of the engineering managers at the Water Purification Center is Crystal Yezman. I contacted her about work at the Center and her role as an engineer. Crystal ensures that the recycled water meets requirements for non-potable (non-drinkable) use; oversees the day-to-day operations and maintenance, which includes equipment failures and budget management; and interacts with the public by giving tours of the plant every week. In fact, I plan to go.

Crystal went on to say that there are more than 100 engineers at the Water Purification Center who work in operations and maintenance, water quality, and others who plan future expansion of the Center. Two types of engineers, chemical and civil, have very different jobs. Chemical engineers deal primarily with the chemical composition of materials that are used in the purification process. They formulate chemicals used at the water Treatment Center.  Civil engineers, on the other hand, work on designing, building, and operating large infrastructure projects. Construction project designs must be approved by a licensed civil engineer to ensure that the project meets codes and regulations.

The new purification process is crucial to water conservation. Water has always been a renewable resource thanks to Mother Nature, but with plants like the Silicon Valley Advanced Water Purification Center, we can speed up that process even more to help save California and states that are panting for this precious resource.


For more information see this video!


Filed Under Civil Chemical