Sanitary sewers carry away all the waste and water that flows out of the showers, sinks, washing machines and toilets we use in our homes and businesses every day. In much of Lehigh County, those sewers form a network of more than 600 miles of pipelines, all connected to the Kline’s Island Wastewater Treatment Plant on the Lehigh River in Allentown.
This enormous system allows us to live comfortably while also keeping our creeks, streams and rivers clean. But all systems this big and complex develop problems as they age. After decades of wear and tear, there’s one challenge that’s becoming difficult for our system to handle: Rainstorms.
More than 120 million gallons of water pour through our sanitary sewer system during a typical rainstorm — enough to fill up the PPL Building in Allentown at least six times over, and as much as five times more water than the sewer system usually handles. The rainwater gushes into the sewers through aging sewer mains and leaky manhole covers, as well as downspouts and sump pumps that are illegally connected to the sanitary sewers. All that extra water has to go somewhere.
During extraordinary rain events, the water can back up and flow out of manhole covers. Sometimes it’s also released in a kind of controlled overflow called a “bypass”: A system designed in the 1920s to keep the sewer plant from being completely overwhelmed in these situations. In all of those cases, a mixture of raw sewage — heavily diluted by all of that rainwater — ends up flowing into local waterways, including the Little Lehigh Creek.
Before 2010, these situations used to happen about twice a year. The system’s capacity was increased in 2010 to help prevent overflows and bypasses, which are now down to roughly every other year. But we need to do a lot better than that.
The U.S. Environmental Protection Agency (EPA) says it’s time to fix this problem, and the local governments and authorities responsible for this system agree. Together, we’re formulating a 25-year plan to repair and improve our sewer system, and we need the help and understanding of residents to make this happen.
How Rainwater Gets In
Some kinds of “sewers” are designed to handle rainwater. Those are “storm sewers,” the giant pipes that collect the water that drains off our streets and roads. Because they handle only rainwater, storm sewers are designed to let that water flow right back into our waterways without treatment.
“Sanitary sewers” are very different. Sanitary sewers are designed to carry only the wastewater from our toilets, showers and other household plumbing — as well as from our businesses — to a treatment center where the water can be cleaned and treated before it’s released into the environment. This system wasn’t intended to handle massive surges of rainwater. But in many places, rainwater gets into the system anyway.
Some homes have sump pumps or downspouts from roof gutters that are illegally connected to the sanitary sewer system. That means during every storm they pour thousands of gallons of rainwater into the system — the equivalent of each homeowner flushing a toilet hundreds of times, every time it rains.
In many other cases, our decades-old sewer pipes have developed their own problems. In a lot of ways, sewer lines are like roads: They’re built to last a long time, but they’re susceptible to damage and wear like any infrastructure. But unlike roads, the sewer lines are underground and difficult to inspect. That makes it hard to find the places where problems exist now, or where they’re likely to happen soon.
After all these years of use, many of our sewer pipes and mains have developed cracks that let in water. Sometimes cracks form from natural shifting in the ground. Other times, cracks are caused by tree roots that push against or squeeze sewer pipes, or that even poke right into the smaller pipes (“laterals”) that connect individual homes to the sewer system.
All those cracks mean there’s a constant flow of some 3-5 million gallons of groundwater into our sewer system every day, mixing with the sewage and filling up the system’s capacity, instead of remaining in the ground as groundwater.
When it rains heavily, the groundwater problem gets far worse: Millions of gallons of rainwater soak through the ground and pour through the cracked pipes and into the system. At the same time, even more rainwater pools on the ground and then pours into the sewer through cracked or damaged manhole covers.
These problems of illegal downspout and drain hookups, together with the cracked mains and pipes that let in water, are called “inflow and infiltration.”
Our massive sewer system already has a lot to deal with, because it has to keep up with the ever-increasing flow of wastewater from new houses and businesses and new sewer hookups. Between wastewater from growing developments and the groundwater that constantly flows into the system, even when it’s sunny our system’s pipeline capacity is nearly maxed out in some locations. When inflow and infiltration problems also let millions of gallons of rainwater pour in, the system simply can’t keep up.
Our sanitary sewer system carries wastewater all the way from Upper Milford Township in the south, from Weisenberg Township in the west, from Whitehall Township in the north, and from almost all points in between in Pennsylvania’s Lehigh County.
Overall, some 600 miles of pipelines built over more than 50 years carry all that wastewater to the nearly 90-year-old Kline’s Island Wastewater Treatment Plant in Allentown, where it’s treated and returned to our environment through the Lehigh River.
The City of Allentown is at the heart of the sewer system. In addition to accounting for sewer hookups for some 118,000 Allentown residents, the city also owns the Kline’s Island facility.
The Lehigh County Authority (LCA) leases the Kline’s Island treatment facility from the city and handles its operation. That means although the authority handles the day-to-day work of treatment, it’s the city that has to approve and pay for any improvements to the Kline’s Island plant that are needed to address this problem.
In the western part of the county, seven neighboring municipalities and sewer authorities have teamed up with each other and the LCA to form the Western Lehigh Sewerage Partnership (WLSP). The group has been working together since 2009 to respond to federal concerns about sewer overflows during raintorms. The group is made up of Macungie, Alburtis, and the townships of Upper Milford, Upper Macungie, Lower Macungie, Lowhill, and Weisenberg.
In addition to the WLSP and Allentown, seven other Lehigh County municipalities also connect to this system: Salisbury, South Whitehall, Whitehall and Hanover townships, as well as Coplay and Emmaus.
The Kline’s Island plant typically handles about 30 million gallons of water per day, more than enough to fill 45 Olympic-sized swimming pools every 24 hours. At maximum, it can handle up to 87 million gallons in a day — that’s about 131 Olympic-sized swimming pools per day. (End to end, they would stretch more than four miles!)
During some rainstorms, even that 87-million-gallon capacity isn’t enough. In those cases, everything over 87 million gallons flows out of the plant — without being treated — at an “outfall” facility. The facility was designed this way decades ago to prevent the sewer system and the Kline’s Island plant from being damaged when there’s too much water flowing in, but obviously this approach doesn’t satisfy modern clean water standards.
The Clean Water Act is the main U.S. law addressing water pollution. Much of the act dates from 1972, when Congress gave the Environmental Protection Agency (EPA) the authority to set wastewater standards and to monitor pollution control programs, among other responsibilities.
Key parts of our sewer system are much older than the 1972 Clean Water Act, meaning they were never built to meet modern clean water standards. In fact, though the Kline’s Island Wastewater Treatment Plant has been updated and improved many times, the facility originally dates from 1929.
The EPA has the power to name local authorities in “Administrative Orders,” which require them to take action to ensure clean waterways. Because of our system’s overflows, in 2007 the EPA named the City of Allentown in an Administrative Order, and then in 2009 named the LCA and the 14 municipalities that connect to the system.
From 2009 to 2016, the communities have spent about $25 million to address the problems in our systems. Work has gone into repairing leaking lines, sealing manholes, and studying wet-weather flows to help prioritize and figure out how to solve the problem. These efforts are a long way from being finished, though, and the next step is for the communities to submit a combined system rehabilitation plan to the EPA by the end of 2017.
Our communities need to cooperate with the EPA’s Administrative Order — first and foremost because working with the EPA will result in a better, more efficient sewer system and will help keep our waterways cleaner!
In addition, if for any reason the communities would decide not to abide by the Administrative Order, the EPA would have to step up its enforcement with more aggressive actions, which would likely end up in costly legal battles or penalties. The better use for all those funds would be to invest them into repairing and improving our sewer system to keep our waterways clean.
Options and Scenarios
Fixing a problem of this magnitude will have to include a lot of approaches, with impacts aimed at every part of our sewer system. Some approaches help address our root problem: The millions of gallons of rainwater flowing into our sanitary sewers, where that rainwater doesn’t belong. Other options include increasing the operating capacity of our system, or building emergency capacity to prevent overflows.
Some of these improvements are more effective, some are less expensive, and some are quicker to achieve. Considering that all of these improvements have to be funded through money from residents’ and businesses’ water and sewer bills, all those factors have to be weighed in trying to find the best, fastest, and most cost-effective solution that will help keep our waterways cleaner.
Here are some of the options the project engineers have considered as they try to balance cost with system performance:
“Interceptors” are the large sewer mains that allow wastewater to flow from one part of our system to another. Building more interceptors increases the amount of water our system can handle.
“Force mains” are like interceptors, with one big difference: Unlike interceptors, which use gravity to keep wastewater flowing through the system, force mains have pumps to move the wastewater much faster. That means the mains can be a lot narrower and still carry the same volume of wastewater, which also allows our system to handle larger amounts of water.
Force mains are smaller and don’t have to follow natural slopes in the landscape like interceptors do — but they’re also significantly more expensive over the long haul because of the cost of pumping.
Most of the sewer mains in our communities have been underground for decades, and nothing can be built to last forever. In many areas, our sewer mains have reached or exceeded their intended lifespan and need to be repaired.
Like the roof on your house or the engine in your car, repairs can be pushed off as long as possible — but eventually, putting off repairs until there’s a crisis will result in a much more expensive problem!
The Sewer Capacity Assurance & Rehabilitation Program was a plan developed by the WLSP partners to respond to the EPA’s 2009 administrative order and address the inflow and infiltration into our system. These repairs are badly needed and, in some cases, overdue.
Removing unauthorized hookups
In addition to cracked and broken sewer pipes, much of the rainwater in our system comes from sump pumps and downspouts from rain gutters that are illegally connected to the sanitary sewer system. Some also comes from sewer connections on private property that have cracked or broken and let water pour in.
Removing all those problems is time-consuming and a big inconvenience for homeowners. But it’s also one of the least expensive and most effective ways of keeping rainwater where it belongs and out of our sanitary sewers. If you think your home might be affected, you can learn how to help correct this problem.
Wastewater storage tanks
Giant basins called “equalization tanks” function like a shock absorber for our sewer system. They’re empty most of the time — but when there’s a surge of rainwater through the system, that water can fill up the tank rather than overflowing the system. If the tanks are big enough, the sewage treatment plant never gets overwhelmed by the volume of water. After the surge, the wastewater and rainwater in the tank can drain gradually into the treatment plant, until the tank empties.
Storage tanks sound like a simple solution. However, they cost a lot of money to build, operate and maintain, considering how infrequently they would be used. They would also take up acres of land next to the Kline’s Island facility, which could limit the plant’s ability to expand or add other treatment systems in the future.
Peak Wet Weather Treatment (“Blending”)
One of the challenges in preventing overflows is that rain doesn’t fall in consistent amounts. Unusually heavy rainstorms pop up every few years and cause things like flooded roadways and leaky basements. But how can a wastewater system prepare for a 25-year storm, or a 50-year storm, or a 100-year storm?
Considering that homeowners’ water and sewer bills are paying for these improvements, how many additional millions of dollars should be spent building additional capacity that would only be used in a giant storm that only comes once every 50 years, for example?
One of the options under consideration by the City of Allentown to help in cases like those would be to prevent overflows by allowing part of the overflow in the sewer system to be partially treated — rather than going through all the usual steps of wastewater treatment — and then blended with the fully-treated water.
Because what’s flowing into the treatment plant in that case would be overwhelmingly made up of rainwater, it might not make sense to treat that heavily diluted wastewater exactly the same as typical wastewater — especially if this approach would help prevent raw wastewater from overflowing directly into our waterways.
Engineering studies have shown this approach would let the Kline’s Island facility still come in below the permitted levels for water discharge into the Lehigh River. It would even come in below the even tougher water quality requirements the City of Allentown imposed on the LCA as part of the Kline’s Island system lease agreement.
The Pennsylvania Department of Environmental Protection is still reviewing this option to confirm those studies and determine whether blending could be included as a part of the plan to stop overflows.
Regional Solutions and Cost
Agreeing on the best solution can be even more difficult, because our sewer system is actually an interconnected network of smaller systems, each with its own oversight through separate municipalities and authorities. Every municipality has its own priorities and challenges.
The best approach allows all these municipalities and authorities to work together and help each other. A big part of the effort will be the repairs that each of the municipalities was going to need to undertake anyway, because parts of their municipal sewer systems have seen decades of wear and tear and are reaching the end of their lifespans.
Rather than leaving each municipality to go it alone, it makes sense to coordinate efforts: For example, a main might need repairing on both sides of a township line, or a road could be torn up just once instead of twice by two different municipalities. There are also possibilities of combining the borrowing power of the municipalities and authorities to get better deals on the bonds that will finance the work. And coordinated scheduling can spread out the demand on local contractors and prevent competition for resources from driving up bids.
Overall, it should be possible to improve sewer service and save money and time by coordinating these efforts using a regional approach.
The proposed plan for fixing our sewer system spreads the work and the expenses over the next 50 years:
Phase I, 2017 to 2025
Lower Macungie Township, Upper Macungie Township, Alburtis, Macungie and Lehigh County Authority would all work to rehab 73 miles of sewer mains — representing about 25 percent of the entire Western Lehigh sewer system. That focus on reducing inflow and infiltration will help reduce our problem at its source, while also carrying out needed repairs on our aging sewer lines.
In addition, this phase would include refurbishment of the Park Pump Station in Allentown along the Little Lehigh and extension and rehab of the existing force main there. It may also include the construction of a new 4-million-gallon equalization tank at the Kline’s Island Wastewater Treatment Plant in 2020.
Phase II, 2027 to 2038
First, in 2026 experts would reanalyze the flow in our sewers, which will have changed because of the Phase I improvements as well as new development, changes in weather patterns and other factors that are even harder to predict.
Based on current projections, the plan for Phase II would then include building four new interceptors and a new pump station. Two more equalization tanks could also be built at the Kline’s Island plant, or blending facilities added at the plant to address wet-weather flows as described on this website.
Phase III, 2039 to 2043
Again, experts would have to re-analyze the condition of our sewers and the volume of water they’re carrying a quarter century from now. Specific plans for repairs and additional capacity to be added in this phase will be developed over the course of Phase I and Phase II.
The total cost of carrying out this plan is expected to be more than $461 million. About 45 percent of that amount — $212 million — would be spent by municipalities on repairing their own municipal sewer systems. Incorporating that municipal work into the larger plan simply results in better coordination and, potentially, cost savings.
It’s impossible to say exactly how each homeowner’s sewer bill will be affected by this project, especially since so much of the work is to be carried out by different municipalities.
Residents in communities that have already been setting aside money for long-expected sewer repairs might not see much of an impact on their bills. On the other hand, where communities have put off saving for repairs on their aging systems, the impact on homeowners will be more significant. Some communities is Western Lehigh County started increasing their sewer rates in 2017 to begin collecting funds for this work. Once the EPA signs off on the plans to fix and improve the sewer system, your municipality will have a better idea of the short- and long-term impact on your bill.
We all benefit from clean water in our rivers, creeks and streams — and we all rely on our massive sanitary sewer system to do its job, letting us live comfortably while also safely handling the wastewater that comes out of all our homes. Repairing and improving our system so it can do its job will require a major investment of our time and money, but it’s all part of doing our best to make our sewers ready for rainstorms.