City of King Water Treatment Facility
Water Samples Through Treatment Process
Water Treatment Facility Filter #4
Chemical Feed System
Ground Storage Tanks
The City of King Water Treatment Facility is a 3 million gallon per day conventional water treatment plant that provides clean drinking water to approximately 25,000 customers over 5 different towns and cities including the City of King, Town of Tobaccoville, Town of Pinnacle, Town of Rural Hall and Town of Pfafftown. Each of the 7 staff member at the City of King Water Treatment Facility ensures that water quality is held to the highest standard and monitors water quality continuously, 24 hours a day, 7 days a week. Water samples are analyzed hourly, daily and monthly to ensure all parameters are met by state and federal regulations. The entire treatment process can be viewed by operators and city personnel via the City of King's SCADA computer system.
The Treatment Process:
Coagulation & Flocculation
Through the conventional water treatment process, water is taken from the Yadkin River and pumped to the facility. Raw water from the Yadkin River has a wide range of turbidity (cloudiness of water) depending on the weather and environmental conditions. Ranges can vary from 2-2000 NTU. Before reaching the facility, the water is treated with a coagulant called DelPAC 2000, a Poly Aluminum Chloride. The raw water and chemical are mixed rapidly through flash mixing, then goes through the next step of flocculation. Flocculation slows down the speed of mixing of chemical and water and allows particles in the raw water to stick together, to form large particles called floc.
After flocculation, sedimentation allows the floc particles that have formed to settle. The bigger the floc, the heavier the floc is, and thus, allows these particles to settle to the bottom. This process uses time and gravity to clean up water quality from its initial raw state. Detentions times (time it takes water to travel through sedimentation basins) usually range from 2-12 hours. The City of King Water Treatment Facility usually averages a detention time of 5-9 hours, depending on water usage. As the floc settles to the bottom, it is collected and disposed every day to the waste part of the treatment facility through a sludge collection system. Clear water rides across the top of the basin and is dosed with sodium hypochlorite (1.4-1.8 mg/L)) before entering into the building for the next treatment process.
Water from the sedimentation basins usually enters each of the four filters with a settled turbidity of less than 1.0 NTU. Filters allow settled water to be filtered through layers of coal and sand, thus cleaning the water and filtering out any unwanted and pathogenic related particles. Water is continually ran through filters. Like any filter, the water plant's filters must be washed to remove all particle trapped by the media. Water plant operators wash filters every 84 hours and send all water that was used in the cleaning process to the waste part of the treatment facility. Once the filter is washed, the filter is placed into rewash to allow media to be packed back down and ensure turbidities are below a .060NTU. Filter numbers typically average between .020 and .030 NTU after filtration, but do not exceed a .09NTU at any time. Water is then placed inside of a clear well after filtration and dosed with caustic soda to bring water PH level to 7.2-7.5. Orthophosphate is also added to keep all water lines coated to prevent corrosion from the treatment plant thought the distribution system and to each customers tap. Water is then stored on site in 4 ground storage tanks totaling 2.5 million gallons of storage.
After the treatment process, water is dosed with sodium hypochlorite (2.0-2.5 mg/L) one last time before being pumped (two 350hp pumps capable of pumping 4800 gallons per minute) from storage tanks at the water facility to a booster station located at Newsome road. Water is housed in 3 ground storage tanks totaling 3.5 million gallons of water. From there, water is pumped to one of the three water towers located throughout the City of King. Water is then gravity fed to each customer tap. Chlorine levels throughout the system vary depending on location, but typically range between 1.0-1.8 mg/L. A total of 7.5 million gallons of water is available in the water system at all times, to ensure water is available for each customer, business, school, park, and fire hydrant located with the water system. This capacity also allows enough water to be stored in the event of a fire emergency.
All water that is used by the water treatment facility has to be cleaned and returned to the watershed in the same condition or better than when it was first used. A full time operator ensures that water quality going back into the creeks and rivers is held to a better quality than originally found and does not harm the watershed or wildlife found in the environment. Water that has been used for waste purposes is collected into a sludge decant tank. Particles and contaminants are allowed to settle to the bottom of the tank, and clean water is dosed with sodium thiosulfate (chlorine remover) before being released back into the environment. All particles, or “sludge”, is ran through a belt filter press. The press takes any sludge in the tank and removes the water through compression. Water removed from the sludge is sent back to the front of the plant to be retreated and the dried sludge is placed into a dumpster and hauled off to a disposal site.
Each employee at the water plant is proud to ensure that water quality being sent out to each and every customer is at the highest quality while still preserving its surround water shed and environment. Through laboratory testing on site as well as contracted labs, water quality is monitored continuously to ensure the high standard set for water. Testing water within the plant is only part of the monitoring, as one employee from the water facility goes out weekly to test water quality throughout the distribution system. Checking water at business, churches, and hydrants allows the water plant staff to have a better understanding of how water quality changes from treatment to the tap. As a customer, please review all notices sent out by the City of King about your water, as well as checking the City’s website at least once a year for the Annual Drinking Water Quality Report. Should you as a customer ever have any questions or concerns about your water, please feel free to contact the City of King Water Treatment Facility. Tours for individuals as well as groups are welcomed and can be scheduled with the Water Plant Supervisor.
City of King Water Treatment Faciltiy
6949 Donnaha Road
Tobaccoville, NC 27050
Phone- (336) 924-8363
Office- (336) 985-1185