95
percent or greater removal of TSS, BOD, TN, and TP
dry tons of biosolids processed per day
6.5
MGD average daily flow
The Western Wake RWRF
The Western Wake Regional Water Reclamation Facility (WWRWRF) is one of three wastewater treatment facilities operated by the Town of Cary. Wastewater treatment at the WWRWRF can be viewed as a process with seven distinct steps supported by a series of ancillary systems. Learn more about these steps and support systems by clicking on the various icons displayed on the image above.
what we do
Treat wastewater to exceptional quality and produce Reclaim Water and Class A Biosolids for benificial reuse
Untreated Wastewater
Treated Wastewater
Cape Fear River Water
Non-Pelletized Biosolid
Pelletized Biosolid (EnviroGems)
760 dry tons per year
1,500 dry tons per year
3 mg/L TSS 3 mg/L BOD <1 mg/L Ammonia <1 mg/L Phosphorus 8 mg/L DO 7.2 pH
280 mg/L TSS 250 mg/L BOD 43 mg/L Ammonia 9 mg/L Phosphorus 0 mg/L DO 7.3 pH
How does wastewater get here?
Headworks
The first step in wastewater treatment is screening and grit removal. These steps are often grouped together as part of the "Headworks" facility. The primary purpose of this step is to remove material that tends to damage downstream processes and equipment. Screens are used to remove general debris like rocks, rags, and wood. Grit tanks are used to remove dense, inert material like sand. Many of these componants difficult to see at Western Wake because they are covered to help manage odor. Learn more about this system by clicking on the various icons displayed on the images above and to the right.
Vortex Grit Removal
Mechanical Screening
Activated Sludge System
Aeration Basin
Clarifier
Western Wake relies on an activated sludge system to remove BOD, Nitrogen, and Phosphorus from the wastewater. "Activated sludge" is a system that leverages the natural activities of microorganisms to treat wastewater. This type of system includes numerous componants, but at its core are two critical features: 1) an aeration basin and 2) a clarifier. The aeration basin provides the physical space for the biological reactions to take place. The clarifier seperates the biology from the treated water; it returns to the biology back to the aeration basin and dicharges clean water for further treatment. Learn more about this system by clicking on the various icons displayed on the images above and to the right.
VIP Basics
Our Virginia Initiative Process (VIP) is operated to maintain specific conditions that enable removal of nitrogen and phosphorus biologically. With carefull control, we are able to achieve high removal rates without chemical addition.
Anaerobic: No oxygen and no nitrate
Anoxic: No oxygen; nitrate is present (<0.5 mg/L)
Aerobic: Oxygen present (1-2 mg/L)
Hybrid: Combination of aerobic and anoxic (DO ~0.5 mg/L)
Tertiary Filters
The previous treatment step (Activated Sludge System) removes most of the major pollutants. The the tertiary filters is a "polishing" treatment step; they are used to remove small particles the clarifiers weren't able to capture. Western Wake utilizes a cloth-style filter technology. Learn more about this system by clicking on the various icons displayed above.
Post-Aeration
Disinfection
UV at a Glance
After disinfection, the treated wastewater goes through Post-Aeration, which is a polishing step. In this process, air is blown into the water to keep the dissolved oxygen concentration at a favorable level (more than 6 mg/L). Learn more about this process by exploring the icons above.
At this point in the treatment process all major pollutants are removed. What remains are disease-causing organisms like viruses. Disinfection systems kill or neutralize those organisms. Western Wake utilitizes Ultra-Violet (UV) light technology to achieve this. UV systems use light rays to damage organisms' cells which prevents them from growing/multiplying. Learn more about this process by exploring the icons to the right and above.
Effluent Pump Station
The last step in the treatment process for Western Wake is pumping. Treated wastewater from the post-aeration basin is conveyed to an Effluent Pump Station which pumps that water to the permited discharge location (referred to as the "outfall"). This facility pumps wastewater over 11 miles and discharges at downstream of the Buckhorn Dam in the Cape Fear River. Learn more about this system by clicking on the various icons displayed on the images above.
Sludge Thickening
Solids (sludge) produced by the WWTP must be treated before disposal. The first solids processing step at Western Wake is Sludge Thickening. We use a belt filter press to thicken sludge from 1% to 18% solids. This process uses a polymer to encourage particle formation and then uses mechanical forces to squeeze the remaining water out. Click on the icons to learn more about this facility.
Return
Thermal Drying
The WWRWRF is designed to produce a Class A Biosolid, which means the end product is safe for public use as a fertilizer. Class A status is achieved by heating the sludge at a specific temperature and for a specific duration. The combination of time and temperature destroys pathogens and significantly reduces vector attraction. The preferred form of end product is called a "pellet", which has a specific size/shape, density, and nutrient content. Our pelletized product is called EnviroGems and is sold to bulk customers. Click on the icons to learn more about this facility.
Chemical Storage
The WWRWRF was designed with numerous chemical systems to support treatment of wastewater, especially the removal of nitrogen and phosphorus. The chemical storage building recieves and stores bulk chemicals for use on site. It also houses pumping equipment to transfer accurate amounts of chemicals to the desired location in the process. Click on the icons to learn more about this facility.
Return
Western Wake RWRF
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Created on October 1, 2020
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Transcript
95
percent or greater removal of TSS, BOD, TN, and TP
dry tons of biosolids processed per day
6.5
MGD average daily flow
The Western Wake RWRF
The Western Wake Regional Water Reclamation Facility (WWRWRF) is one of three wastewater treatment facilities operated by the Town of Cary. Wastewater treatment at the WWRWRF can be viewed as a process with seven distinct steps supported by a series of ancillary systems. Learn more about these steps and support systems by clicking on the various icons displayed on the image above.
what we do
Treat wastewater to exceptional quality and produce Reclaim Water and Class A Biosolids for benificial reuse
Untreated Wastewater
Treated Wastewater
Cape Fear River Water
Non-Pelletized Biosolid
Pelletized Biosolid (EnviroGems)
760 dry tons per year
1,500 dry tons per year
3 mg/L TSS 3 mg/L BOD <1 mg/L Ammonia <1 mg/L Phosphorus 8 mg/L DO 7.2 pH
280 mg/L TSS 250 mg/L BOD 43 mg/L Ammonia 9 mg/L Phosphorus 0 mg/L DO 7.3 pH
How does wastewater get here?
Headworks
The first step in wastewater treatment is screening and grit removal. These steps are often grouped together as part of the "Headworks" facility. The primary purpose of this step is to remove material that tends to damage downstream processes and equipment. Screens are used to remove general debris like rocks, rags, and wood. Grit tanks are used to remove dense, inert material like sand. Many of these componants difficult to see at Western Wake because they are covered to help manage odor. Learn more about this system by clicking on the various icons displayed on the images above and to the right.
Vortex Grit Removal
Mechanical Screening
Activated Sludge System
Aeration Basin
Clarifier
Western Wake relies on an activated sludge system to remove BOD, Nitrogen, and Phosphorus from the wastewater. "Activated sludge" is a system that leverages the natural activities of microorganisms to treat wastewater. This type of system includes numerous componants, but at its core are two critical features: 1) an aeration basin and 2) a clarifier. The aeration basin provides the physical space for the biological reactions to take place. The clarifier seperates the biology from the treated water; it returns to the biology back to the aeration basin and dicharges clean water for further treatment. Learn more about this system by clicking on the various icons displayed on the images above and to the right.
VIP Basics
Our Virginia Initiative Process (VIP) is operated to maintain specific conditions that enable removal of nitrogen and phosphorus biologically. With carefull control, we are able to achieve high removal rates without chemical addition.
Anaerobic: No oxygen and no nitrate
Anoxic: No oxygen; nitrate is present (<0.5 mg/L)
Aerobic: Oxygen present (1-2 mg/L)
Hybrid: Combination of aerobic and anoxic (DO ~0.5 mg/L)
Tertiary Filters
The previous treatment step (Activated Sludge System) removes most of the major pollutants. The the tertiary filters is a "polishing" treatment step; they are used to remove small particles the clarifiers weren't able to capture. Western Wake utilizes a cloth-style filter technology. Learn more about this system by clicking on the various icons displayed above.
Post-Aeration
Disinfection
UV at a Glance
After disinfection, the treated wastewater goes through Post-Aeration, which is a polishing step. In this process, air is blown into the water to keep the dissolved oxygen concentration at a favorable level (more than 6 mg/L). Learn more about this process by exploring the icons above.
At this point in the treatment process all major pollutants are removed. What remains are disease-causing organisms like viruses. Disinfection systems kill or neutralize those organisms. Western Wake utilitizes Ultra-Violet (UV) light technology to achieve this. UV systems use light rays to damage organisms' cells which prevents them from growing/multiplying. Learn more about this process by exploring the icons to the right and above.
Effluent Pump Station
The last step in the treatment process for Western Wake is pumping. Treated wastewater from the post-aeration basin is conveyed to an Effluent Pump Station which pumps that water to the permited discharge location (referred to as the "outfall"). This facility pumps wastewater over 11 miles and discharges at downstream of the Buckhorn Dam in the Cape Fear River. Learn more about this system by clicking on the various icons displayed on the images above.
Sludge Thickening
Solids (sludge) produced by the WWTP must be treated before disposal. The first solids processing step at Western Wake is Sludge Thickening. We use a belt filter press to thicken sludge from 1% to 18% solids. This process uses a polymer to encourage particle formation and then uses mechanical forces to squeeze the remaining water out. Click on the icons to learn more about this facility.
Return
Thermal Drying
The WWRWRF is designed to produce a Class A Biosolid, which means the end product is safe for public use as a fertilizer. Class A status is achieved by heating the sludge at a specific temperature and for a specific duration. The combination of time and temperature destroys pathogens and significantly reduces vector attraction. The preferred form of end product is called a "pellet", which has a specific size/shape, density, and nutrient content. Our pelletized product is called EnviroGems and is sold to bulk customers. Click on the icons to learn more about this facility.
Chemical Storage
The WWRWRF was designed with numerous chemical systems to support treatment of wastewater, especially the removal of nitrogen and phosphorus. The chemical storage building recieves and stores bulk chemicals for use on site. It also houses pumping equipment to transfer accurate amounts of chemicals to the desired location in the process. Click on the icons to learn more about this facility.
Return