We let the soapy dishwater go down the drain. We flush the toilet. We shower or bathe, and the water goes down the drain and it’s gone. But in reality, it isn’t nearly as simple as it looks, Mike Hopf explained during HV1’s tour of the plant. Water Department Superintendent Hopf, who is also the acting Sewer Department superintendent, has been supervising both departments since the former Water superintendent Alphonse “Mike” Marino left in 2021.
Water comes into the plant from the collection system, working through two pump stations, Hopf said. One is on East Bridge Street, right near Tina Chorvas Park, and one on Ripley Street, which is behind Krause Chocolates. “They both pump here, plus there’s gravity that comes from the rest of the collection system.”
The septic receiving station has two tanks into which haulers can dump sludge. “Then we feed into the waste stream. We take up to 12,000 gallons a day, but on average I’d say it’s no more than 8,000 gallons a day of septage, and some days there isn’t any. We feed that into the stream slowly, about 12 gallons a minute, and that gets treated along with the sewage.”
Rags are caught in a screen as the wastewater flows through and are manually removed by an operator, and then the waste stream goes through a grinder to make the solids smaller. The sludge sinks to the bottom of the tank and is removed periodically. The waste stream goes through several processes to remove as much of the suspended solids as possible. The water then goes through a set of rotating biological contactors (RBCs), in which microorganisms further break down the sewage, which is deposited as sludge.
The waste stream passes through two sets of four units each, although for nearly two years one bank of contactors only had three units, and while the replacement unit was installed only one bank of four units was usable. The system is now up to full capacity, Hopf said. Any solids that are left over are removed in a secondary clarifier. “The secondary clarifier can do the same job as the primary clarifier, but with a lot less loading,” he explained.
“At this point, we’ve removed as many of the solids as we can, we’ve treated the solid BOD [biological oxygen demand] with the RBCs, and we’ve removed more solids, so the only thing left is one disinfection. We want to kill off the fecal coliform; we use chlorine to do that. After the chlorine has killed off any bacteria, it goes out into the Esopus Creek.” As we look, we can hear ducks quacking in the creek. “We sometimes see bald eagles here, too.”
Solids are pumped out of the clarifiers and into a gravity thickener, where the sludge sinks. “It uses gravity to thicken the sludge. The sludge will settle out and thicken even more, and from here we’ll pump it into our primary digester, where it will spend 14 to 22 days digesting, breaking down the volatile organics, and then transferring over to the secondary digester.”
One problem is that the pumps moving the sludge, which date to the plant’s opening in the 1980s, and many of the valves in the basement of the building are no longer working. “It makes it hard to operate these digesters.”
In a final step, the sludge is run through a press, in which it is squeezed between two belts, increasing the solids in the mix from about five percent to 26 percent solids. Reducing the weight of the sludge by reducing the water content reduces the weight of the sludge, reducing the cost of shipping and treating it at the facility in Pennsylvania, where it is converted to compost.
Removing the digester cover “gives us the opportunity to see what pumps are working, what valves are working or not working the level of sludge and what brings it down. It’s been a good process.
From the secondary digester it goes to the belt filter press, and then we dewater the sludge, and then it goes onto the conveyor and into a truck.”
The removed material is tested daily in the plant laboratory. Tests include temperature, acidity, level of solids and other characteristics of the treated sewage. A daily log of operations is kept in the lab, a daily checklist of work completed, recording and data logging, “so if something is off, you see it.”
The State Department of Environmental Conservation checks regularly. “We just had an inspection in September, and they spent three hours going through the plant, just like we did, and then they went through all the paperwork.” On the other hand, a lot of the operation is self-governing: People in the plant do the reporting and recordkeeping and send the records to the DEC. “If something is out of whack, we report it. If there’s a noncompliance event, we report that.”
Hanging on the wall is a map of the collection system, built in the 1800s, as it was in 1902. The map does not include many of the Village streets, many of which were built later. A picture of the plant as it appeared in 1902 is also there. At that time, “It was just a settling tank,” Hopf said.
The lid of the secondary digester now rests just outside the entrance to the plant office, giving the impression of a large sculpture or a landed flying saucer. “We took it off there so we could see the inside of the secondary digester, do an inspection and remove the sludge that’s down in there. The cover on the primary digester is a fixed cover and it can’t be removed. The secondary digester has a floating cover, and that captures all the methane gas there, which we burn off with our flame.”
Trustee Donald Hackett, who oversees the sewer plant, has suggested that the methane be used to heat the plant, rather than being burned off. It would save the cost of gas that is now purchased from Central Hudson. The plant at one time was heated by oil. Then Central Hudson provided gas for heating. Whether methane would provide fuel for the plant would require some study; it is possible, but they don’t know without looking into the possibility more closely, Hopf said.
When the sewer plant was built, the area was industrial and there were few homes in the area. At that time, odor was not a problem. As homes were built closer to the plant, residents complained of odors from the plant, and that is one factor that is being addressed and could be included in any upgrades.
The digester that was recently cleaned out and is now open for possible repair could help reduce the odors, Hackett has said. “I think it has the potential to, but I think you have a mostly anaerobic facility that is going to create hydrogen sulfide. Those areas need to be covered up, so like the headworks, where everything was open, the primary clarifier; so the potential exists [to cut the odors]. Getting at all the solids, getting them cleaned out. So, we’ll see.”
The project, a facility upgrade, has to be done, Hopf said. “Whether we can get grants, so we don’t put the full cost on the backs of our customers and the sewer users. We’ll have to see what happens and take it from there.” Overall, the plant has a good record with meeting compliance standards, other than the problems with the RBC being down, Hopf said. “As good as that is, it doesn’t always help when you’re looking for the money.”
In addition to the plant itself, “We’re also responsible for the collection system, the streets, the manholes, sewer mains coming here and two other pump stations.” The department has five staff members; two are dedicated to the collection system, but help out here at the facility: Joe Hunter, the belt operator, and Sarina Augustine. Joe Myers and Hopf are hands-on managers; they don’t just supervise, Hopf said. Recently, while they were using a video camera to check a line, the camera got stuck in a rootball. “I had to go in; I got all geared up, put my harness on, got my tripod, tested the air to be sure it was safe to enter, got on a ladder, went down and got the camera out.”
No, a simple toilet flush is not as simple as it looks.