Franklin Wastewater Treatment Plant

Madison Powers
October 31, 2011
Franklin, New Hampshire
1:30 PM

      A quick bus ride to nearby Franklin brought my AP Environmental class to the Franklin Wastewater Treatment Plant today. We get off the bus to a relatively nice day, minus the 6 inches of snow on the ground, and are greeted by a man named Ken Noyes, the Chief Operator of the plant and employee for 22 years. My first impression of Noyes was that he was a man who worked hard and was passionate about his job. He was to be our tour guide for the rest of the afternoon.
       Ken began with a little background on the plant. The plant was built in 1979 on the Merrimack River, as a part of the Clean Water Act, a government effort to clean rivers and public water of waste. This act made it illegal for wastes to be dumped in rivers, which at the time, had been very common, for it was one of the easiest ways to get rid of waste. The Franklin area used to be very industrial, and there were many textile mills on the edges of the Pemigewasset and Winnipesaukee Rivers, both of which join to create the Merrimack, on which the plant is located. Many of these textile mills, Ken explained, used dyes to color their materials, and these dyes were disposed of in the rivers. Ken grew up in a near by town, and said, "I grew up in that area, where you couldn't swim or fish in the Winnipesaukee," due to their dirtiness. He remembers seeing pieces of toilet paper and feces floating down the river as a kid. People dumped everything in the river, and the Wastewater Treatment Plant was the solution to this problem.

The Head Works

      Ken brought us through the main building, showing us how a majority of the plant was controlled. A large majority of the plant was controlled by computer, and many of the pump stations along the rivers were controlled by that one computer, too. The program kept track of the pH of the water (which was 7.23 at the time), the number of gallons coming in a day (today it was around 6 million gallons),  the microorganisms in the tanks, how fast the water was flowing, etc. The computer could do it all. Ken remember back before the computer, when it used to take 3 or more people to respond to an alarm at a pump station 40 minutes away, and now it only takes a click of a button, and can be done at home on a laptop instead of having to go out at 1 in the morning, for example. Ken explained that there were 14 major pump stations in the area that he could control, and over 60 miles of sewage lines connecting all of the towns along the Pemigewasset and Winnipesaukee Rivers, which is quite a large area.
      Ken brought us outside to where the water flowed into the plant, an area known as the head works. The smell outside was pretty bad, a smell of septic and sewage, but as soon as we walked over the top of the hill at the head works, I gagged a little. It was extremely overpowering, and the closer I got to the waste water, the worse it got. Eventually my nose just shut down, but the smell still lingered. Ken introduced us to these two tanks with water flowing fairly quickly through them, known as the head works, where the preliminary treatment was done. In these tanks were two mechanical screens which removed a majority of the large debris. "Anything flushed down the toilet shows up here," Ken said. From McDonald's toys, to 2x4s, to $3000 cash, Ken has seen it all, though 90% of the debris is feminine products and toilet paper. Ken said that 99% of the substance that flows through the head works is water, the other 1% being the solids. Also, even though 6+ million gallons of water flow through the plant each day, 70% of the state's households don't send their waste water to the plant. Many of them have their own septic systems, which later are brought to the plant via truck.

      Our next stop was the primary clarifier, a massive round tank with two rotating rake arms used to remove the solids from the water. There was an upper and lower arm. The upper arm removed the floatable solids, which are solids that float on the surface of the water, for example kitchen grease. The lower arm removed the heavy solids, which are the solids that settle to the bottom. Another type of solid in the water are the dissolved solids, which are the hardest to get out of the water. These three types of solids make up the total suspended solids, or the TSS, which the state requires that the plant removes 85% of the TSS from the waste water. Ken also mentioned another important thing here, the biochemical oxygen demand of the water, or the BOD. Ken said the waste puts an oxygen demand on the river, and "It will deplete the oxygen from the river," because it chokes out the oxygen that organisms in the river need to live. Ken said that tests for BOD are not good because they take five days to do, and by then, the water will have already cycled through the plant. 40-45% of the BOD is usually removed from the water though, which is good.

      From here, Ken brought us to the aeration tanks, where oxygen and microorganisms are pumped into the water to aid in the cleaning process. Ken said, "We don't add any chemicals at all to remove the solids  and BOD, it's all natural." Microorganisms are used to treat the water, eating the solids in the water to dispose of them. Ken has the ability to build up the population of the microorganisms in the tank depending on how much TSS there is. Generally in the summer there is much more solid waste, so he needs more "bugs" to eat it, whereas in the winter, there is much less and the microorganisms are less active. Ken also said, "I smell the tanks and it tells me what the microorganisms are like. I can tell if something is wrong by the smell." He knows what good and what's bad by the smell of the tanks, though I'm not really sure what would be considered a good smell and a bad smell there, for they all smelled bad to me.

Empty Aeration Tank

      We passed by one of the empty aeration tanks on our way to our next stop, and Ken talked about the diffusers that supply oxygen. There were many in the bottom of the tanks, as we could see, and were vital in the removal of the solids. He also mentioned that TSS usually is at about 250 mg/L and BOD is between 200-225 mg/L, which makes the removal of it easier, but when there is a large amount of water coming into the plant, for example after a big rain storm, the levels drop to sub 100 g/L levels, which makes the removal harder, so he opens more tanks to make it more likely the solids are removed. We arrived at the secondary clarifier, which is the same as the first, but it catches anything that is missed. Here is where the microorganisms are pumped out. Ken goes through about 2,800 pounds of bugs a day, and they usually last for a 6 day cycle. From the secondary clarifier they are pumped back to the aeration tanks. We noticed some seagulls at the secondary clarifier and Ken mentioned that the tanks often attract turkey vultures, bald eagles, and ducks. He's seeing many of these animals more frequently, and said, "I've seen things in my adult life that I never saw growing up," meaning the increase in animal life.

Cleaner Water at the Secondary Clarifier

      The last step was the disinfection of the waste water before it could be put into the Merrimack. We made our way to a little building where the water is disinfected using both chlorine and UV light. The UV light zaps the water for 0.23 seconds, changing the DNA of the cells so that they are no longer capable of disease or reproduction. Ken showed us the lights, and the "mountain dew" water, the fluorescent green water that is seen under the lights. Chlorine is also used to disinfect, though it is much less efficient, for it takes 15 minutes for it to do it's job, uses a larger space, and can be more dangerous. A new UV facility was being built that would save the plant 40% on energy, would get rid of the chlorine method, and allow for 36 million gallons to be disinfected a day. This new building cost $4 million, whereas the whole plant cost $8 million back in 1979.

"Mountain Dew" Water

      Ken showed us the holding tanks for the solid wastes, and what it was turned into. Two types of microorganisms are used to get rid of the solid waste: acid formers and methane formers. The acid formers eat the sludge, forming acid, which the methane formers eat to form methane gas and residual sludge. The big red tanks were used to hold the methane. Ken said, "We heat the whole building with methane gas," which is why the area and the building had a funky smell. The bug tanks were also heated with this methane gas. The left over sludge can also be used for fertilizers, though the small traces of metal in it can be dangerous for people's health. Ken finished off by showing us the laboratory, where many tests are done on the waste water. The water is tested monthly for metals, such as copper, and annually tested for major pollutants. He said that the annual test includes tests for over 600 different pollutants. That's a lot to keep track of.

The Laboratory

       Overall, the Franklin Wastewater Treatment Plant was an excellent and eye opening experience. While it may have been a little bit smelly, the experience was worth it. I applaud Ken for his 22 years of service at what seems to be a tough job. He went from the bottom to the top, with all his hard work and long hours put in on the job and in school. His passion for the job and to improve the environment was inspiring. I had no idea that that much had to be done to sewage water to make it semi-clean again. It was interesting learning about how people in the past have ruined their water sources and created health issues/environmental issues because they were too lazy to dispose of their waste the right way. The plant plays a large part in the local rivers' ecosystems, and without it, the ecosystems may be in much worse shape than they are. The Franklin Wastewater Treatment Plant plays an important role in keep the environment clean and healthy.