 |
||||||||||||||||
System Performance Annual Report
|
||||||||||||||||
|
General Manager |
Thomas E. Hartye, P.E. |
(828) 254-9646 |
|
Director of Wastewater Treatment (WRF) |
John Kiviniemi (ORC) |
(828) 252-7342 |
|
Operations Manager (WRF) |
Dennis Lance (ORC-Backup) |
(828) 252-7342 |
|
Director of System Services (Collection System) |
Barry Cook (ORC) |
(828) 255-0061 |
|
System Services Coordinator (Collection System) |
Ken Stines (ORC-Backup) |
(828) 255-0061 |
Permit Numbers:
-
NPDES Permit # NC0024911
-
Marketing & Distribution Permit # WQ0007174 (class A residuals)
-
General Storm water Permit # NCG110003
-
Air Quality (WNCRAPCA) Permit # 11-0772
-
Collection System # WQCS00004
II. Description of Facilities
A. Collection System- System Services Division
The MSD service area covers approximately 180 square miles. The MSD provides service to areas along the French Broad River Valley and the Swannanoa River Valley as far as Ridgecrest. There are about 900 miles of public sanitary sewer line, 30 public pump stations within the collection system and approximately 25,000 manholes system wide. Less than 65 miles are large interceptors with diameters ranging from 24" to 66". One third of the balance is small 6" lines and two-thirds are medium size lines ranging from 8" up to 24". Most of this pipe is between 50 and 100 years old, and is in dire need of rehabilitation or replacement. The Districts 45,000 customers reflect a service population of about 135,000 people.
About 40% of the water treated at the Districts Wastewater Reclamation Facility (WRF) is Infiltration (The groundwater that seeps in through cracks in pipes and manholes), and Inflow (rainwater entering through manhole lids and unauthorized Storm Water connections). The District has embarked on an aggressive program to abate this problem.
B. Wastewater Reclamation Facility (WRF)
The present Wastewater Reclamation Facility (WFR) is a 40MGD secondary treatment plant serving Buncombe County (specifically Asheville, Biltmore Forest, Black Mountain, Montreat, Weaverville, Woodfin and Buncombe County at large). Overall, the MSD services approximately 45,000 separate sewer customers, a combined customer population of 135,000, and over 30 separately billed industries. The facility treats a current average daily flow of 18.2 million gallons per day. The WRF is an attached growth design, comprised of 152 rotating biological contactors (RBC's), which provide full secondary treatment. These RBC's provide 450-500 acres (3+ acres each unit) of surface area for biological growth. It has been said that MSD's facility is the largest RBC plant in the world. The plant consists of:
Preliminary Treatment Components
-
IDI Barscreens (2 units) w/screenings compactor and shaftless screw conveyer
-
Influent Pumps (3 units) - 35 MGD rated capacity each
-
Aerated Grit Chambers (3 units) w/associated grease removal
Primary Treatment Components
-
Primary Microscreens (7 units) - 250 micron screens
Secondary Treatment Components
-
1st Stage RBC's (44 units)
-
2nd Stage RBC's (72 units)
-
3rd Stage RBC's ( 36 units)
-
Intermediate Pumps (3 units) - pump water to clarifier from 3rd RBC stage
-
Intermediate Clarifier (4 cells - total volume 2 MG)
-
Secondary Microscreens (18 units) - 27 micron screens
Disinfection Components
-
Sodium Hypochlorite solution - average feed 1000 gallons/day at 8% solution strength
Residuals Handling Components
-
Gravity Thickeners (2 units) - 100 foot diameter each
-
Gravity Belt Thickeners (4 units)
-
2.5 Meter Belt Presses (2 units)
-
Anaerobic Digesters (2 units) - 100 foot diameter each
-
Fluidized Bed Incinerator (40DT/day rated)
-
Alkaline Stabilization Facility (40DT/day rated)
Energy Management Components
-
2 Megawatt Diesel Generator (full back-up/emergency power for WWTP)
-
450 Kilowatt Gas Generators (2 units) - operate on natural, digester or landfill gas
-
850 Kilowatt Hydro Turbines (3 units) - induction units (French Broad River source)
Automation Components
-
Foxboro Distributed Control System (DCS) - full automated control of WWTP
Sludge Management Plan
-
MSD utilizes its fluidized bed incinerator as its primary residual management option, with alkaline stabilization as a secondary management option - as well as maintains an arrangement with the Buncombe County landfill (lined) for emergencies. Presently the facility is managing 12-15 DT's per day of residuals. The facilities are designed for 40DT's per day. Due to the lack of true primary clarifiers, most of the sludge generated at the facility is secondary in nature (i.e. sloughings from the RBC's). Sludge is thickened in on-site gravity thickeners to a consistency of 4-7% solids at which time it is then pumped to the 2 1/2-meter belt presses. These units dewater the sludge to over 24% solids and then it is pumped to the incinerator. The facility maintains gravity belt thickeners and anaerobic digesters, however these units are presently not being utilized. Air emissions from the incinerator are of excellent quality. Recent air emissions testing place removal efficiency of the air scrubbers at 99+% for regulated parameters. Incinerator ash is thickened on-site via a gravity ash thickener and then pumped to an on-site lagoon. Groundwater is monitored in accordance with NCDENR requirements (up & down gradient). When alkaline stabilization operations are activated, a class A product is produced and distributed to the public. The alkaline add-mixtures utilized in the process are fly ash, cement kiln dust (CKD) and lime kiln dust (LKD). The process incorporates the use of the "N-Viro" process when these alkaline products are utilized in accordance with the patented mix recipe. Due to the fact that the incinerator operations provide much more cost-effective management, it is utilized as the primary option. Supplementary fuel is required due to the 24% solids content, however landfill gas is utilized in place of more costly natural gas. However natural gas and/or #2 fuel oil can also be utilized. MSD also maintains an "agreement" with the local county landfill (lined) to dispose of dewatered sludge during emergency and/or maintenance/breakdown instances; this provides a 3rd residuals management alternative.
III. Improvements to Facilities
A. Collection System Improvements
Since the 1990, wherein MSD assumed ownership and maintenance of the local public collection systems staff has undertaken an aggressive program to correct existing known collection system problems. Between 1990 and 2007, over 650,000 linear feet of pipe have been replaced and over $182 million has been re-invested in sewer rehabilitation projects. However, due to the large size of the MSD system, there is much work still to be done. From 2007 to 2017, the District expects to rehabilitate or replace an additional 500,000 lineal feet.
Approximately $137 million will be spent for the Districts Capital Improvement Program (CIP) over the next 10 years. Of this, 19% will be spent on rehabilitating medium to large interceptors, 73% on rehabilitating or replacing small collection lines, and 8% on the treatment plant and pump station projects. The total estimated cost to rehabilitate the Districts aged collection system and WRF facilities over the next twenty year period is estimated at over $274 million.
MSD recently developed a "Pipe Rating" program which is a new approach to evaluating aging sewer lines and prioritizing rehabilitation projects. It accomplishes this through a combination of Closed Circuit Television (CCTV) review, pipe-defect rating, a Geographic Information System (GIS), and engineering analysis. This award winning program is used as an active tool to generate and prioritize rehabilitation projects.
MSD maintains an aggressive Preventative Maintenance Program whereby approximately 637,000 lineal feet of sewer lines are cleaned per year by high pressure water jetting equipment. In addition, about 107,000 linear feet of sewer lines are mechanically or chemically treated to remove tree roots and blockages. A program to clear MSD Right-of-Ways has been implemented with 37,000 ft cleared this year.
B. Wastewater Reclamation Facility Improvements
-
Installation of new sludge cake (Schwing) pump & associated controls
-
Installation of 2 new RBC blowers & associated controls
IV. Performance Measures
A. Collection System, System Services Division
-
The District has an aggressive Preventative Maintenance program of high pressure cleaning and root control. This year 1,050,000 LF of pipeline was cleaned by in-house crews and contractors or approximately 22% of the 900 miles of system. Closed circuit TV inspections were performed on the basins cleaned for use in prioritization and design pursuant to the District's Capital Improvement Plan (650,000 LF).
-
System Services division completed and submitted to NCDNR-DWQ two-six month High Priority Line Inspection Reports and one Increased Inspection and Maintenance Report as required. The High Priority Line report documents inspection of aerial lines, siphons and lines in proximity to vulnerable creeks and streams. The Increased Inspection Report documents oversight of problem sewer lines in the 10 year CIP, all of which must be inspected once every three years until replaced.
-
The collection system recorded 52 sanitary sewer overflows (SSO's). All SSO's were remediated according to the District's standard operating procedures for sanitary sewer overflow cleanup and no environmental impact occurred.
Attachments (These documents are in Adobe Acrobat format. To download a free Acrobat Reader CLICK HERE)
B.Wastewater Reclamation Facility (WRF)
Performance measures were again achieved during the FY07 annual reporting period. The WRF continues to provide effective/efficient treatment services to the community averaging CBOD & TSS removal efficiencies of 91% and 90% respectively. Flow to the WRF continues to decrease, with an average flow of 18.2 million gallons per day - the combination of the near drought conditions and loss of industrial flows was the main contributors to the reduced flows. The WRF remained in full compliance for all permitted parameters and received a favorable review by NC-DENR regional office staff with respect to the annual facility inspections. The regional air quality agency provided MSD with a similar inspection review/report.
MSD maintained its service contract agreement with Pace Analytical, Inc. (NC certified lab). This agreement incorporates the exchange of full laboratory testing services for use of the existing laboratory space. This progressive opportunity continues to yield significant long-term savings to MSD.
MSD was again recognized for outstanding wastewater treatment efforts by the National Association of Clean Water Agencies (NACWA - formerly AMSA) and received the prestigious NACWA Platinum Award signifying consistent NPDES permit compliance. MSD was one of few member agencies around the country who were honored with this award representing excellence in environmental protection.
The WRF successfully participated in a surveillance audits (both internal & external) regarding ISO14001 certification - coming through with zero (0) non conformances. This program, also referred to as an Environmental Management System, continues to provide significant benefits to MSD both in the short & long-term.
Attachments (These documents are in Adobe Acrobat format. To download a free Acrobat Reader CLICK HERE)
-
Plant location map with contours (This is a large file--1/2Mb)
V. Certification
I certify under penalty of law that this report is complete and accurate to the best of my knowledge. I further certify that this report has been made available to the users and customers of the MSD system and that those users have been notified of its availability.
____________________________________________
Thomas E. Hartye, P.E. August 30, 2007
General Manager
Metropolitan Sewerage District of Buncombe County, NC
If you would like a hard copy or more information...
Write to webmaster@msdbc.org
Home | About Us | Employment Opportunities | Contact Us | Annual Report | Site Map
|
©Copyright
Metropolitan Sewerage District of Buncombe County |
||
 |
 |
|