Plant Spotlight: Greenville Utilities WWTP
Thursday, July 21, 2016
Greenville Utilities WWTP
By Jason Manning, Greenville Utilities Superintendent and Chris Hill, Operations Coordinator
Edited by John Rutledge, Smart Cover Systems (NC AWWA-WEA Plant Operations & Maintenance Committee)
This Plant Spotlight was originally printed in the Summer 2016 issue of NC Currents magazine.
Located in eastern NC, the City of Greenville is the largest city in Pitt County with a current population of approximately 91,000. In addition to 15 major manufacturing facilities, Greenville is home to East Carolina University and a well-respected medical community.
Greenville Utilities, established in 1905, is owned by the citizens of Greenville, but operates under a separate charter issued by the N.C. General Assembly. GUC is a Public Not for Profit Municipal Agency. In addition to water & wastewater services, GUC provides electric & natural gas services to the City of Greenville and 75% of Pitt County. GUC serves a combined total of nearly 150,000 customer connections.
Greenville Utilities currently operates one WWTP that services a population of 91,000 plus which includes Greenville and neighboring Bethel and Grimesland, NC. It was originally put into operation in 1985 with a rating of 10.5 MGD. In 1995, it underwent an upgrade that increased the plant rating to 17.5 MGD. The WWTP currently employees a total of 29 plant and pump station staff. They consist of 20 O&M, four Laboratory & five administrative personnel. The plant has an annual operating cost of approximately $8 million.
The plant treats both domestic and industrial wastewater from the city and the surrounding community.
The plant influent consists of approximately 90% domestic and 10% industrial wastewater.
The plant’s effluent discharges into the Tar River, a Class C-NSW water in the Tar-Pamlico River Basin. The WWTP has a design flow of 17.5 MGD and operates with an average daily flow of 10.6 MGD. Peak flow is 30 MGD.
The key treatment processes include:
- (2) Bar Screens
- (2) Grit Removal Systems
- (1) Odor Control System
- (5) Aeration Basins with Diffused Air
- (2) Biological Phosphorous Removal Basins
- (5) Secondary Clarifiers
- (7) Tertiary Treatment Deep Bed Sand Filters
- (1) UV Disinfection System- 2 Channel
- (3) Aerobic Digesters
- (2) Belt Filter Presses
- (1) Hauled Waste Receiving Station
The WWTP is permitted for a total flow of 17.5 MGD and operates two liquid treatment processes.
The North Plant was constructed in 1985 and is comprised of three treatment trains and utilizes nitrified recycle to reduce nutrients in the final effluent.
The South Plant was constructed in 1995 and employs two oxy-ditches and biological phosphorous removal cells to attain enhanced biological nutrient removal. The effluent from both plants receives secondary clarification and tertiary treatment with sand filters. The final effluent is UV disinfected prior to discharge to the Tar River.
Both the North & South plants are in “good” overall operating condition due to an active inspection and maintenance program. Current two year ADF average (May 2013-2015) is 10.60 MGD and consumes 61% of available permitted capacity.
Biosolids are dewatered on site and trucked to contracted vendor for composting. Class A compost is the final disposition of all biosolids produced at this facility.
Current and Future Expansion
UV Disinfection Upgrade Project began construction in late 2015 and is scheduled for completion in the spring of 2016. The goal of this project is to install a more reliable and energy efficient disinfection system sized to handle Peak Flows. The current horizontal UV system is being replaced by a two channel UV system that uses modules consisting of vertical UV lamps. Energy efficiency is achieved by the ability to turn on and off modules of UV lamps to meet the lowest diurnal flows. Reliable disinfection will be increased by this effort.
Air Piping Upgrade Project is currently in the engineering phase. The GUC staff identified issues with compressed air delivery to the South Aeration Basins. An energy efficiency study quantified energy losses in the air piping of over $172k /year. This future project will increase energy efficiency, reduce operational risks and allow staff increased operational control of aeration.
Biosolids/Dewatering Upgrade Project is currently in the engineering phase. The GUC Board approved a Biosolids Project budget to increase the sustainability and operational effectiveness of the biosolids management. The project will also be scoped to include nutrient management of dewatering process side streams.
Electric/SCADA Upgrade was completed in early 2016. The WWTP was recently upgraded with redundant electrical support for all critical equipment. A self-healing fiber ring was installed to support a comprehensive SCADA upgrade for the plant and pump station.
Master Plan for the WWTP was recently completed. This Master Plan projects future demand and the required infrastructure improvements needed to meet forecasted customer demand and predicted asset condition due to age, use and environment. The Master Plan also takes into account regulatory constraints and plots current plant performance against those predicted limits. Where performance gaps are identified – projects are proposed and supported. All aforementioned projects were accurately predicted in the Master Plan. Future projects (within 5-year window), such as additional clarification on the South Plant, will be focused on increasing treatment and permitted capacity.
The facility is fully automated using the latest SCADA technology and equipment, but is easily operated by hand if the need arises. The recently updated servers and software were installed to improve operation and efficiency. In addition, operations, maintenance, and lab tasks are scheduled and logged using an Oracle based work order management system. This system is easily accessible by desktop and by iPad.
Waste Activated Sludge (WAS) is stored in three aerobic digesters. Discharge from the digesters is sent to two Andritz belt filter presses for dewatering. Currently these units produce approximately 2,000 dry tons per year at an average of 17.5%.
All dewatered biosolids are sent to McGill Environmental for treatment and final disposal as a raw product for compost. The WWTP staff samples the biosolids quarterly and provides analysis results to McGill Environmental. McGill Environmental is responsible for all Class A Biosolids regulatory reporting.
Construction began in late 2015 to remove the existing energy intensive UV system and replace it with one that is more energy efficient. The new replacement is an Ozonia (Suez) UV system that utilizes vertical UV lamp modules and has met all expectations.
Laboratory & Pretreatment
The laboratory is staffed by three laboratory technicians who have several years of experience. They are certified for 27 parameters with the State. The lab performs sampling at various locations on the plant for analysis and is involved with many projects at the plant. GUC currently regulates six Significant Industrial Users and four non-Significant Industrial Users as part of the pretreatment program. The pretreatment program is staffed by one Industrial Pretreatment Specialist who samples all industrial locations and judges compliance once lab staff has completed the analysis. The pretreatment/lab section of GUC’s WWTP functions paperless for the most part. The staff is seeking certification in WW Operations and in Pretreatment. As regulations evolve, the staff adjusts accordingly.
The wastewater effluent is permitted for the following limits:
- BOD limit 8.0 mg/l (summer): 15.0 mg/l (winter)
- NH3 limit 4.1 mg/l (summer): 8.2 mg/l (winter)
- Annually allocated 249,576 lbs of Total Nitrogen and 45,103 lbs of Total Phosphorus through the Tar Pamlico Basin Association
Personnel Development Programs
Greenville Utilities offers many internal training and development opportunities for all of its employees. These include customer service, self-leadership, situational frontline leadership, career advancement, safety, diversity, interviewing, and many more.
The WWTP is a Grade 4 facility. Operations, maintenance, lab and administrative staff are encouraged to achieve the highest level of certification in wastewater, collections, maintenance, lab analysis, leadership, and other related areas.
Among the WWTP operations and laboratory staff, there are certified Wastewater Treatment Operators, certified Land Application Operators, certified Spray Irrigation Operators, certified Wastewater Collection System Operators, certified Lab Analysts, a certified Pretreatment Specialist, a licensed Public Pesticide Operator, a certified Maintenance Technologist, and a licensed Plumbing, Heating and Fire Sprinkler Contractor.
Among the WWTP maintenance staff, there are certified Maintenance Technologists, an ISA Certified Control Systems Technicians, a licensed Public Pesticide Operator, a State Board of Refrigeration Examiners Universal Technician, an EPA R410a certified Technician, certified Collection Systems Operators, and certified Wastewater Operators.
Greenville Utilities offer flexible scheduling for both laboratory and maintenance personnel. Flexible scheduling has allowed the individual to choose a schedule which is best for their family. For example, Lab staff may choose to work four 10 hour days- this provides a benefit for the employee, the employee’s family and Greenville Utilities with increased hours of laboratory support. The managerial approach to personnel is to ensure all individuals know their worth to the plant and are provided opportunities to add value to the operation.
Safety and Health Program
Highlights of the program include Lighthouse Observation; American Heart Association First Aid, CPR and AED training; and Smith Driving System. Lighthouse is a peer observation program that reinforces positive work habits instead of punishing bad work habits. Smith Driving System is the leading provider of collision avoidance driver training and all GUC employees must complete this program every three years.
- NC Department of Labor Certificate of Safety Achievement
- 2008 WEF George W. Burke, Jr. Facility Safety Award
- 2001 EPA Operations & Maintenance Excellence Award
- 1999 EPA Beneficial Use of Biosolids Award
- 1998 EPA Biosolids Beneficial Use (Large Operating Projects) – Honorable Mention
Some of the challenges that the operations staff have faced is implementation of Oracle Work and Asset Management fully integrated with GUC’s Financial Accounting System – Oracle’s EBS, ESRI GIS and SCADA.
Historically, the WWTP and Pump Station Staff have struggled with planning, executing and documenting work performed. Operation and maintenance of critical assets relied on word of mouth or hand written notes. GUC did not have an enterprise system in place to know what assets they had, what their value was and how they used and maintained them. In the span of less than a year, Operations and Maintenance Staff successfully transitioned to a digital – mobile mode of performing and documenting work. Plant and Pump Station Staff utilize iPads to issue work requests, record operational readings, record work effort, inspection information and access SCADA information remotely.
GUC is evolving into an asset management mindset – this is a cultural shift for employees and management alike. GUC has been blessed with visionary leadership that empowers the employees with technology and tools to be more efficient and effective for the ratepayers.
The plant is an exceptionally performing facility that is 100% biological. The staff has eliminated chemical additions in the process. The final effluent flows to the Tar River via a channel that is teeming with aquatic life that supports wildlife living on acreage behind the facility, which belongs to Greenville Utilities Commission. Wildlife such as deer, turkey, and eagles nesting can often be seen. The facility is a visually beautiful treatment plant with various trees and vegetation throughout the property. The reclaimed water from the plant is used for irrigation to enhance this landscape. The plant staff takes much pride in the operation, maintenance and appearance of the facility.
For additional information please contact
Jason Manning, WWTP Superintendent (firstname.lastname@example.org)
Chris Hill, Operations Coordinator (email@example.com)
240 Aqua Lane
Greenville, NC 27834
Phone: (252) 551-3304