Pigs aren’t just farm animals or crispy snacks. In water treatment, the term “pig” refers to a piece of equipment inserted into a pipe to clean and inspect pipelines. It’s much less cute and tasty than an actual pig, but certainly important for our water safety!
At Heneghan and Associates, P.C. (HA), we work with municipalities and water companies to design their water systems, including the equipment needed to keep them clean and efficient. Pigging helps prevent major sanitation problems by regularly cleaning out the pipes, while also alerting water operators to any issues inside the waterlines.
So when’s the last time your water system was pigged, and what does the process actually involve?
Pigging sounds complicated, but the idea is quite simple. A pig launcher releases a pig into the pipeline, and the pressure of the pumps pushes it through the pipe to the receiving station, or pig catcher. The pig forces out debris, which improves the flow rate. It also inspects the pipes from the interior. That information is then reported back to the water operators, who can determine what maintenance is needed.
In addition to improving the flow, pigging reduces the bacteria and chemical deposits in the water. The National Environmental Services Center explains that it’s common for distribution lines to develop a biofilm inside the pipe. This biofilm is made up of a group of bacteria that doesn’t respond to our usual water treatment or disinfection processes. A combination of pigging and flushing will scrape out this biofilm as well as excess chemical deposits, which improves water safety.
The earliest versions of pigs are called “dumb pigs” and consisted of straw and barbed wire. According to National Public Radio (NPR), the metal made a squealing sound as it traveled through the pipes, which led to the name. We now use “smart pigs” to do this work, so called because they can use sensors to store data and locate problems. New pigs are usually made of food-safe silicon, which accommodates this technology and doesn’t contaminate our drinking water.
American Pipeline Solutions, a pigging company, recommends that cities pig their water mains every one to five years, depending on the system’s load and the size of the pipes. But pigging only works in pipelines that are designed for it. Most modern water systems are designed with pigging in mind, but some older pipes can’t be pigged in this traditional way.
Even if a system is designed to allow pigging, water operators must make sure that the pipelines can handle a pig. The pipe’s diameter must be wide enough so the pig won’t get stuck and small enough that the water pressure will keep the pig moving. If the pipe is too old or corroded, pigging might cause it to fail completely. You can learn more about possible pigging problems (and solutions!) here.
It’s important to stay updated about your water system’s health so that you can perform maintenance as needed, not when catastrophe strikes. Smart pigs give you an insider’s look — literally — into how your water system is running, one pipe at a time.
If that wasn’t reason enough to consider pigging your system, remember that this process also discourages bacteria growth and improves water flow. This is especially important for fire hydrants, which tend to quickly develop buildup because of the small size of the waterline. The last thing you want is slow water flow in the middle of an emergency.
Instead of completely replacing waterlines — a costly and inconvenient undertaking — your city or water company can use pigging to improve the pipes’ effectiveness and keep your water system clean.
As a civil engineering and land surveying company, Heneghan and Associates, P.C. always designs water systems with pigging in mind. Check out our previous water engineering projects to get a feel for how we design our systems. We offer specialty services in water and wastewater engineering. No matter how old or big your water system is, we work with entities of all varieties to implement systems that will provide clean water to customers as efficiently as possible.
Contact us or visit our website to talk to an engineer who can evaluate your system and design solutions that will keep your water flowing. We might be a civil engineering and land surveying firm, not a farm, but we’re experts when it comes to pigs!