If you’ve been following Aquastructure, our monthly blog series that breaks down all the details about how we bring fresh drinking water to our customers, then you know we put a great deal of effort into purifying our water.
From filtering out dirt and debris to zapping away bacteria and adjusting pH levels, we closely monitor our water at the source, during treatment and after treatment to ensure the final product meets and exceeds regulatory requirements.
In the past, we’ve discussed the different types of filtration processes for both surface water treatment and groundwater treatment, but we wanted to dig even deeper into the scientific details. We sat down with Director of Treatment for Aqua Pennsylvania Matt Miller, whose team is responsible for optimizing the treatment of drinking water and wastewater throughout their state, to clear things up. (Pun intended.)
Welcome to the fantastic world of filtration!
If you take one thing away from this blog, we hope it’s the importance of coagulants in the filtration process. Coagulants are vital chemicals that help tiny pieces of debris particles in surface water stick together and form larger clumps so they can easily be removed from the water.
All those organic particles that creep into the surface water have a negative charge. The coagulants, meanwhile, have a positive charge, meaning that they act like magnets and repel against each other when combined. When this happens, we’re able to neutralize those unwanted particles. They begin to stick together, which makes it easy to flush them out of the water.
Remember these diagrams? Behold: Coagulation and filtration!
Coagulants aren’t the only substances working wonders on our water, though. There’s also sand, gravel, and anthracite, which more or less act as filters.
“If you have ever been to the beach, poured a pail of water onto the sand, and watched it disappear, you have witnessed filtration,” Miller explained.
Just like sand at the beach, in a water filter, the water moves down through tiny pores in sand and gravel, trapping all of the little particles that don’t need to be in our drinking water. From there, the filtered water flows through an ion-exchange filter that trades undesirable contaminants, like calcium and magnesium ions, for harmless substances, such as potassium or sodium.
Aerate, chlorinate, repeat.
Sometimes, the pH levels in surface water and groundwater are a little out of whack. That’s because when carbon dioxide is in the water, it forms a weak acid called carbonic acid. Carbonic acid isn’t very fun for the body to digest, so we implement a process called aeration, which is a fancy term for the addition of air into the water. This removes any carbon dioxide and normalizes pH levels.
Last, but definitely not least, is chlorination. According to Miller, the use of chlorine is the most common and effective process for disinfecting drinking water. This powerful substance is used to kill bacteria and prevent the spread of waterborne diseases. However, too much chlorine is no good, so our operators carefully monitor the amount of chlorine added to each batch of water.
Welcome to chlorination nation!
How does chlorine work, you may ask?
Well, it all comes down to the fact that chlorine, which is an oxidizing agent, has a neutral charge, meaning that it’s able to sneak into the negatively-charged pathogens and destroy them so they don’t multiply and make us sick.
With all this talk of positive, negative and neutral charges, do you feel like you’re back in elementary school science class? We sure do!
It’s time to get sludgy.
Now that we’ve covered the science of our drinking water, let’s talk about wastewater. We’ve already walked you through what happens to the water after you flush, so you’ll remember that there’s some pretty intensive cleaning done by itty-bitty microscopic organisms. This wastewater cleaning process is appropriately termed The Activated Sludge Process. (Can you think of a cooler name? We sure can’t.)
“Most times, we think of sludge as a bad thing, but in this case, sludge is a community of bacteria that each have a particular function,” Miller says. “The sole purpose for these bacteria is to eat and reproduce.”
The sludge loves to eat all the not-so-yummy leftovers in our wastewater, like ammonia and nitrate. Interestingly, depending on what type of contaminants the sludge needs to eat, Aqua will monitor the bacteria’s access to oxygen, since the gas can affect the processes. By the end of their meal, the bacteria are full and happy, and our water is ready to head back to the local rivers or streams.
All this technical talk has us sure of one thing: Science is all around us, from the water we drink to the processes and technologies that make it clean enough to do so.
Thanks for joining us on another part of our Aquastructure journey. We hope you’ve learned as much as we have!