SD1 provides several services to benefit the environment and the residents of Northern Kentucky, but one of the most important is the collection and treatment of wastewater.
Wastewater is the flow of used water from a community or city. Wastewater comes from many sources, including homes, businesses, schools and industries. While most people think of it as only sanitary sewage, wastewater flow includes water from showers, sinks, dishwashers, car washes, hospitals, food processing operations and more.
Wastewater from homes and businesses is funneled into SD1’s sanitary sewer system where it can be safely transported to a wastewater treatment plant, cleaned and emptied into the Ohio River without hurting the environment or making people sick.
This wastewater system is like an enormous and complex sewage superhighway comprised of sewer lines, pump stations and treatment plants. Each drop of dirty water must travel a complicated route to reach its final destination, a treatment plant. Along the way, the wastewater flow moves from smaller pipes to larger mainlines and can be sped up, detoured and re-routed, just like road traffic.
Stops along the Sewage Superhighway
A private sanitary sewer lateral is your driveway to the sewage superhighway. Laterals are pipes that connect homes to SD1’s public sanitary sewer system, moving wastewater from the drains in the building to the public system. Just like a driveway, if you own your home, you also own your lateral and are responsible for maintaining it.
Maintaining that private lateral is an important job. If your lateral is broken, blocked or improperly connected to SD1’s system, your wastewater is unable to travel its course on the sewage superhighway and may back up into your home.
To make maintaining private laterals easier, some homes have sewer lateral cleanouts, which are vertical pipes that connect an underground lateral to the surface. Sewer lateral cleanouts have removable caps so homeowners and plumbers can quickly access laterals and prevent messes such as sewage backups in homes.
Infrastructure refers to the huge network of underground pipes that carries wastewater from private laterals to a wastewater treatment plant. These underground pipe systems are the main roads that make up the sewage superhighway.
SD1’s infrastructure is made up of about 1,600 miles of pipe that range in size from six inches wide to 12 feet tall. There are more than 7.5 miles of pipe large enough to drive a car through!
Some of these pipes are very old and some are brand new. SD1 did not build all of Northern Kentucky’s infrastructure. Instead, we inherited neighborhood sewer systems and connected them together. Because of this, parts of SD1’s system are more than 100 years old and were built to outdated standards or to serve much smaller populations.
The earliest infrastructure built in Northern Kentucky was combined sewer systems, which carry sewage from buildings and storm water runoff from rainfall in the same pipes. During dry weather, the pipes in SD1’s combined sewer system carry mostly sewage from homes and businesses and deliver it to a wastewater treatment plant for cleaning. During rainy or snowy weather, however, the pipes can become filled with runoff.
Separate sewer systems, on the other hand, have two networks of underground pipes. The sanitary network carries sewage to a wastewater treatment plant, and a separate storm water network carries runoff from rain water and snowmelt to the nearest body of water to prevent flooding. Separate sewer systems can be found in the more recently-developed areas of Northern Kentucky.
Because there are so many different types of infrastructure and many are very old, SD1 is constantly at work to check for damage and upgrade pipes to ensure the sewage superhighway is operating at maximum efficiency.
On the underground sewage superhighway, pump stations are like entrance ramps to the interstate: they funnel wastewater from one pipe to another and increase the speed of the flow.
Most of the sewage in SD1’s system flows to a wastewater treatment plant through gravity lines, pipes that are tilted downward so that sewage flows downhill. However, because Northern Kentucky is so hilly, sewage must be pumped uphill in some areas by one of SD1’s pump stations.
Wastewater from many different pipes flows into one of SD1’s pump stations and is then pumped into a sewer force main. Sewer force mains use pressure to pump wastewater upward. If rain or snowmelt cause a large amount of water to flow to pump stations, SD1 will turn on additional pumps.
SD1 protects pump station equipment with small buildings that allow employees to maintain and operate the equipment. These buildings are the only visible part of the pump station and are small compared to the large amount of machinery built underground.
The wastewater treatment plant is the final stop for wastewater on the sewage superhighway before it reaches the Ohio River.
In addition to several smaller wastewater treatment plants, SD1 operates three major wastewater facilities, including Dry Creek Wastewater Treatment Plant in Villa Hills, Eastern Regional Water Reclamation Facility in Alexandria and Western Regional Water Reclamation Facility in Petersburg.
SD1’s treatment plants clean and disinfect Northern Kentucky’s wastewater before eventually returning the treated water to the Ohio River. Several steps have to be taken during the treatment process to make sure the wastewater is clean enough to be released into the environment.
SD1’S Wastewater Treatment Process
In addition to haulers bringing in the contents of septic tanks, large pipes carry wastewater to the treatment plant. Immediately, this incoming water is treated to control odor. Then, it is filtered through bar screens that separate out debris. This debris is hauled away by trucks to a landfill.
Next, oxygen circulates through the water, stimulating the growth of microorganisms that eat the organic matter in the sewage. The microorganisms that digested the organic waste sink to the bottom, while the cleansed water on top flows into an exit pipeline.
The wastewater is then sent to new tanks to settle. The solids that settle out of the wastewater are treated to remove as much water from them as possible. The end product, known as biosolids, is collected in large dumpsters and sent to a landfill.
Before it is emptied into the river, wastewater is disinfected, either with chlorine or ultraviolet light. If chlorine is used, the water is treated again to neutralize the chlorine in order to make it safe for the environment.