Norwich Public Utilities maintains and operates the City's 8.5 million gallon per day wastewater treatment plant and sanitary sewer distribution system (mains and pump stations.) The wastewater treatment plant is a vital part of our City's efforts to control pollution and protect our local water sources. The wastewater treatment plant protects public health from disease-causing bacteria and viruses. By protecting the water quality of our rivers and streams, the wastewater treatment plant allows us to enjoy the natural beauty of our community.
In addition to waste collected from the 120 mile distribution system, the wastewater treatment plant collects and treats waste brought in from septic haulers.
NPU offers free tours of the Wastewater Treatment Plant to local school groups. Tours take approximately 2-3 hours. For more information, complete a tour request form.
Connecting to the sanitary sewer system
For information about connecting your home or business to the sanitary sewer system contact a NPU project coordinator at 860-887-2555 to ensure the availability of city sewer at your property. The NPU project coordinator will assist you through the process of connecting to the city sewer system if it's available to your property.
Note: A Sewer Capital Connection fee is charged for any new sewer connection, or change of use to an existing sewer connection. For more information, read the Sewer Capital Connection Fee document.
How a Wastewater Treatment Plant Works
Wastewater treatment takes place in two steps:
1. Primary Treatment: The sewer distribution system carries the wastewater from homes and businesses to the plant. In some areas, "combined" sewers carry storm runoff as well. Once the wastewater enters the facility, the trash and heavy solids are removed. Smaller particles are settled in the sedimentation tanks. The settled material, called "sludge" is removed. The primary treatment process removes about 60% of the solids.
2. Secondary Treatment: Air is added to the wastewater, along with microorganisms. The air helps the helpful microorganisms grow and consume the harmful organic matter. A secondary sedimentation tank allows the microorganisms and solid wastes to form clumps and settle. The settled material, or "sludge" is removed. A disinfectant is added to the wastewater to kill any remaining organisms. The clean water flows into the Yantic River. The sludge is removed and properly disposed of in a sanitary manner.
Challenges in treating wastewater
The wastewater treatment process is very complicated and should not be taken for granted. There are many external factors that can interfere with the biological and chemical sanitization (excessive storm water, toxic chemicals) and likewise the wastewater process, if not managed correctly, can introduce harmful chemical nutrients (such as phosphorus and nitrogen) into the environment. To protect the community and environment, the wastewater treatment plant operators must be trained to respond to changing conditions. Wastewater treatment plant operators undergo a stringent training and certification process.
"Clean Rivers, Clean Harbor, Sound Norwich"
"Clean Rivers, Clean Harbor, Sound Norwich" is a community wastewater project that addresses the impact our city's wastewater plant and pipeline network has on the future and the quality of our harbor and rivers. The project involves changes to the wastewater infrastructure that will:
• Bring Norwich current with state and federal environmental mandates
• Upgrade the city's aging wastewater infrastructure to reduce treatment plant odors
• Minimize the discharge of untreated waste into local rivers during wet weather
• Reduce nitrogen from sewage discharge, making our rivers, harbor and Long Island Sound cleaner
• Power the sewer plant using recaptured methane gas, reducing Norwich's energy costs
• Prepare Norwich to meet current growth and future business development needs