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HomeMy WebLinkAboutNC0021491_Authorization to Construct_20180627in I June 27, 2018 North Carolina Department of Environmental Quality Division of Water Resources NPDES Complex Permitting Unit 512 N. Salisbury Street, 9th Floor Raleigh, North Carolina 27604 Subject: Town of Mocksville Contract 11.0 — Dutchman's Creek WWTP Renovation NPDES Permit No. NCO021491 Request for Authorization to Construct Gentlemen: 1984.015 (34) The Town of Mocksville is planning to modify its existing Dutchman's Creek Wastewater Treatment Plant. In general, the project consists of constructing a headworks structure with screening, two clarifiers, a sludge pumping station, and an aerobic digester. Ancillary equipment will also be added as part as this project, including blowers, process pumps, and a sludge thickener. The existing headworks, clarifiers, and RAS/WAS pump stations will be demolished. Construction is anticipated to begin in mid 2019 and is expected to be completed within 1 -year. On behalf of the Town, we respectfully request an Authorization to Construct. Enclosed please find one set, along with a CD containing the following documents, for your review: • Original executed Application for Authorization to Construct (Form ATC -12-14) • NPDES Permit No. NCO021491 • Engineering Plans • Engineering Specifications • Engineering Calculations • Residuals Management Plan Should you have any questions or need additional information, please feel free to call me at 704.338.4668 or email me at chuck@willisengineers.com. Yours very truly, WILLIS INE RS Charles A. illis Jr., P.E., BCEE Enclosures cc: Town of Mocksville 10700 Sikes Place, Suite 115 Charlotte, North Carolina 28277 704.377.9844 / NC License F-0114 State of North Carolina Department of Environmental Quality Division of Water Resources Water Resources ENVIRONMENTAL QUALITY APPLICATION FOR AUTHORIZATION TO CONSTRUCT PERMIT (FORM ATC -12-14) SECTION 1: INSTRUCTIONS AND INFORMATION A. The Division of Water Resources will accept this application package for review only if all of the items are provided and the application is complete. Failure to submit all of the required items will result in the application package being returned as incomplete per 15A NCAC 02T .0105(b). B. Plans and specifications must be prepared in accordance with 15 NCAC 02H. 0100, 15A NCAC 02T, North Carolina General Statute 133-3, North Carolina General Statute 143-215.1, and Division of Water Resources Minimum Design Criteria for NPDES Wastewater Treatment Facilities. C. The plans and specifications submitted must represent a completed final design that is ready to advertise for bid. D. Any content changes made to this Form ATC -12-14 shall result in the application package being returned. E. The Applicant shall submit ONE ORIGINAL and ONE DIGITAL COPY (CD) of the application, all supporting documentation and attachments. All information must be submitted bound or in a 3 -ring binder, with a Section tab for each Section, except the Engineering Plans. F. Check the boxes below to indicate that the information is provided and the requirements are met. G. If attachments are necessary for clarity or due to space limitations, such attachments are considered part of the application package and must be numbered to correspond to the item referenced. H. For any project that requires review under the State Environmental Policy Act (SEPA), an Authorization to Construct cannot be issued prior to the completion of a State Clearinghouse advertisement period for a FONSI, EIS, etc. unless the project qualifies for a Determination of Minor Construction Activity. I. For more information, visit the Division of Water Resources web site at: https://deg.nc.gov/about/divisions/water-resources/water- resources-permits/wastewater-bra nch/n Ades-wastewater/authorization-to-construct. J. In addition to this Authorization to Construct, the Applicant should be aware that other permits may be required from other Sections of the Division of Water Resources (for example: reclaimed water facilities permits; Class A or B biosolids residuals permit). SECTION 2: APPLICANT INFORMATION AND PROJECT DESCRIPTION A. APPLICANT Applicant's name Town of Mocksville Signature authority's name per 15A NCAC 02T .0106(b) Leonard Barefoot Signature authority's title Interim Town Manager Complete mailing address 171 South Clement Street, Mocksville, NC 27028 Telephone number 336-753-6700 Email address Ibarefoot@mocksviIlenc.gov B. PROFESSIONAL ENGINEER Professional Engineer's name Charles A. Willis Jr., P.E., BCEE Professional Engineer's title President North Carolina Professional Engineer's License No. 17710 Firm name Willis Engineers Firm License number F-0114 Complete mailing address 10700 Sikes Place, Suite 115, Charlotte, NC 28277 Application for Authorization to Construct Permit (FORM ATC -12-14) Page 1 Water Resources ENVIRONMENTAL DUALITY State of North Carolina Department of Environmental Quality Division of Water Resources APPLICATION FOR AUTHORIZATION TO CONSTRUCT PERMIT (FORM ATC -12-14) Telephone number 704-377-9844 Email address chuck@willisengineers.com C. NPDES PERMIT NPDES Permit number NCO021491 Current Permitted flow (MGD) — include permit flow phases if applicable 0'98 D. PROJECT DESCRIPTION Provide a brief description of the project: The Proiect consists of constructing a headworks structure with screening, two clarifiers, a sludge pumping station, and an aerobic digester. Ancillary equipment will also be added as part as this project, including blowers, process pumps, and a sludge thickener. SECTION 3: APPLICATION ITEMS REQUIRED FOR SUBMITTAL FOR ALL PROJECTS A. Cover Letter ® The letter must include a request for the Authorization to Construct; the facility NPDES Number; a brief project description that indicates whether the project is a new facility, facility modification, treatment process modification, or facility expansion; the construction timeline; and a list of all items and attachments included in the application package. ❑ If any of the requirements of 15 NCAC 02H. 0100, 15A NCAC 02T, North Carolina General Statute 133-3, North Carolina General Statute 143-215.11 and Division of Water Resources Minimum Design Criteria for NPDES Wastewater Treatment Facilities are not met by the proposed design, the letter must include an itemized list of the requirements that are not met. B. NPDES Permit ® Submit Part I of the Final NPDES permit for this facility that includes Part A (Effluent Limitations and Monitoring Requirements) for the monthly average flow limit that corresponds to the work that is requested for this project. C. Special Order by Consent ❑ If the facility is subject to any Special Orders by Consent (SOC), submit the applicable SOC. ® Not Applicable. D. Finding of No Significant Impact or Record of Decision ❑ Submit a copy of the Finding of No Significant Impact or Record of Decision for this project. ❑ Provide a brief description of any of the mitigating factors or activities included in the approved Environmental Document that impact any aspect of design of this project, if not specified in the Finding of No Significant Impact or Record of Decision. ® Not Applicable. E. Engineering Plans ® Per 15A NCAC 02T .0504(c)(1), submit one set of detailed plans that have been signed, sealed and dated by a North Carolina Licensed Professional Engineer. Application for Authorization to Construct Permit (FORM ATC -12-14) Page 2 State of North Carolina Department of Environmental Quality Division of Water Resources Water Resources ENVIRONMENTAL QUALITY APPLICATION FOR AUTHORIZATION TO CONSTRUCT PERMIT (FORM ATC -12-14) ® Per 21 NCAC 56 .1103(a)(6), the name, address and License number of the Licensee's firm shall be included on each sheet of the engineering drawings. ® Plans must be labeled as follows: FINAL DRAWING — FOR REVIEW PURPOSES ONLY — NOT RELEASED FOR CONSTRUCTION. ® 15A NCAC 02H .0124 requires multiple (dual at a minimum) components such as pumps, chemical feed systems, aeration equipment and disinfection equipment. Is this requirement met by the design? ® Yes or ❑ No. If no, provide an explanation: Plans shall include: ® Plans for all applicable disciplines needed for bidding and construction of the proposed project (check as appropriate): ® Civil ❑ Not Applicable ® Process Mechanical ❑ Not Applicable ® Structural ❑ Not Applicable ® Electrical ❑ Not Applicable ❑ Instrumentation/Controls ® Not Applicable ❑ Architectural ® Not Applicable ❑ Building Mechanical ® Not Applicable ❑ Building Plumbing ® Not Applicable ® Plan and profile views and associated details of all modified treatment units including piping, valves, and equipment (pumps, blowers, mixers, diffusers, etc.) ® Are any modifications proposed that impact the hydraulic profile of the treatment facility? ® Yes or ❑ No. If yes, provide a hydraulic profile drawing on one sheet that includes all impacted upstream and downstream units. The profile shall include the top of wall elevations of each impacted treatment unit and the water surface elevations within each impacted treatment unit for two flow conditions: (1) the NPDES permitted flow with all trains in service and (2) the peak hourly flow with one treatment train removed from service. ® Are any modifications proposed that impact the process flow diagram or process flow schematic of the treatment facility? ® Yes or ❑ No. If yes, provide the process flow diagram or process flow schematic showing all modified flow paths including aeration, recycle/return, wasting, and chemical feed, with the location of all monitoring and control instruments noted. F. ® Engineering Specifications ® Per 15A NCAC 02T .0504(c)(2), submit one set of specifications that have been signed, sealed and dated by a North Carolina Licensed Professional Engineer. ® Specifications must be labeled as follows: FINAL SPECIFICATIONS — FOR REVIEW PURPOSES ONLY — NOT RELEASED FOR CONSTRUCTION. Specifications shall include: ® Specifications for all applicable disciplines needed for bidding and construction of the proposed project (check as appropriate): ® Civil ❑ Not Applicable ® Process Mechanical ❑ Not Applicable ® Structural ❑ Not Applicable ® Electrical ❑ Not Applicable ® Instrumentation/Controls ❑ Not Applicable Application for Authorization to Construct Permit (FORM ATC -12-14) Page 3 Nater Resources ENVIRONMENTAL. QUALITY ❑ Architectural ❑ Building Mechanical ❑ Building Plumbing State of North Carolina Department of Environmental Quality Division of Water Resources APPLICATION FOR AUTHORIZATION TO CONSTRUCT PERMIT (FORM ATC -12-14) ® Not Applicable ® Not Applicable ® Detailed specifications for all treatment units and processes including piping, valves, equipment (pumps, blowers, mixers, diffusers, etc.), and instrumentation. ® Means of ensuring quality and integrity of the finished product including leakage testing requirements for structures and pipelines, and performance testing requirements for equipment. ® Bid Form for publicly bid projects. G. Construction Sequence Plan ® Construction Sequence Plan such that construction activities will not result in overflows or bypasses to waters of the State. The Plan must not imply that the Contractor is responsible for operation of treatment facilities. List the location of the Construction Sequence Plan as in the Engineering Plans or in the Engineering Specifications or in both: Sheet G-1 of Engineering Plans. H. Engineering Calculations ® Per 15A NCAC 02T .0504(c)(3), submit one set of engineering calculations that have been signed, sealed and dated by a North Carolina Licensed Professional Engineer; the seal, signature and date shall be placed on the cover sheet of the calculations. For new or expanding facilities and for treatment process modifications that are included in Section 4.C, the calculations shall include at a minimum: ® Demonstration of how peak hour design flow was determined with a justification of the selected peaking factor. ® Influent pollutant loading demonstrating how the design influent characteristics in Section 4.13.2 of this form were determined. ® Pollutant loading for each treatment unit demonstrating how the design effluent concentrations in Section 4.13.2 of this form were determined. ® Hydraulic loading for each treatment unit. ® Sizing criteria for each treatment unit and associated equipment (blowers, mixers, pumps, etc.) ® Total dynamic head (TDH) calculations and system curve analysis for each pump specified that is included in Section 4.C.6. ® Buoyancy calculations for all below grade structures. ® Supporting documentation that the specified auxiliary power source is capable of powering all essential treatment units. I. Permits ® Provide the following information for each permit and/or certification required for this project: Permit/Certification Not Date Applicable Submitted Date Approved Permit/ Certification Number If Not Issued Provide Status and Expected Issuance Date Dam Safetv x Soil Erosion and Sediment Control July 2018 USCOE / Section 404 Permit x Water Quality Certification (401) x Application for Authorization to Construct Permit (FORM ATC -12-14) Page 4 0 Yater Resources ENVIRONMENTAL QUALITY State of North Carolina Department of Environmental Quality Division of Water Resources APPLICATION FOR AUTHORIZATION TO CONSTRUCT PERMIT (FORM ATC -12-14) USCOE /Section 10 x Stormwater Management Plan x CAMA x NCDOT Encroachment Agreement x Railroad Encroachment Agreement x Other: Residuals Management Plan ® For all new facilities, expanding facilities, or modifications that result in a change to sludge production and/or sludge processes, provide a Residuals Management Plan meeting the requirements of 15A NCAC 02T .0504(j) and 15A NCAC 02T .0508; the Plan must include: ® A detailed explanation as to how the generated residuals (including trash, sediment and grit) will be collected, handled, processed, stored, treated, and disposed. ® An evaluation of the treatment facility's residuals storage requirements based upon the maximum anticipated residuals production rate and ability to remove residuals. ® A permit for residuals utilization or a written commitment to the Applicant from a Permittee of a Department approved residuals disposal/utilization program that has adequate permitted capacity to accept the residuals or has submitted a residuals/utilization program application. ❑ If oil, grease, grit or screenings removal and collection is a designated unit process, a detailed explanation as to how the oil/grease will be collected, handled, processed, stored and disposed. ❑ Not Applicable. Application for Authorization to Construct Permit (FORM ATC -12-14) Page 5 State of North Carolina Department of Environmental Quality Division of Water Resources Wates- Resources ENVIRONMENTAL QUALITY APPLICATION FOR AUTHORIZATION TO CONSTRUCT PERMIT (FORM ATC -12-14) SECTION 4: PROJECT INFORMATION A. WASTEWATER TREATMENT PLANT FLOW INFORMATION —COMPLETE FOR NEW OR EXPANDING FACILITIES 1. Provide the following flow information: Application for Authorization to Construct Permit (FORM ATC -12-14) Page 6 Plant Flows Existing Plant Design MGD Current NPDES Permit Limit MGD Current Annual Average (past 12 months) MGD For Past 12 Months: Start Date: month/yr End Date: month/yr For Past 24 Months: Start Date: month/yr End Date: month/yr Maximum Month MGD MGD Maximum Day MGD MGD Peak Hour MGD MGD Application for Authorization to Construct Permit (FORM ATC -12-14) Page 6 B. WASTEWATER TREATMENT FACILITY DESIGN INFORMATION —COMPLETE FOR NEW OR EXPANDING FACILITIES AND FOR TREATMENT PROCESS MODIFICATIONS 1. Have all of the requirements of 15 NCAC 02H. 0100, 15A NCAC 02T, North Carolina General Statute 133-3 North Carolina General Statute 143-215.1, and Division of Water Resources Minimum Design Criteria for NPDES Wastewater Treatment Facilities been met by the proposed design and specifications? ® Yes or ❑ No. If no, provide justification as to why the requirements are not met, consistent with 15A NCAC 02T .0105(n): 2. Provide the design influent and effluent characteristics that are used as the basis for the project design, and the NPDES permit limits for the following parameters: 3. Based on the "Project Basis of Design" parameters listed above, will the proposed design allow the treatment facility to meet the NPDES Permit Limits listed above? ® Yes or ❑ No. If no, describe how and why the Permit Limits will not be met: Application for Authorization to Construct Permit (FORM ATC -12-14) Page 7 Project Basis of Design Design Influent Design Influent Influent Concentration Load Concentration - (Must be (Must be Current Annual supported by supported by Design Effluent Average (past Engineering Engineering Concentration and/or NPDES Permit Limits 12 months) if Calculations Calculations Parameter Available [Section 3.H]) [Section 3.H]) Load (monthly average) Ammonia Nitrogen 2.0 mg/L Summer 2.0 mg/L Summer (NH3-N) N/A mg/L 30 mg/L 245 Ib/day 2.0 mg/L Winter 4.0 mg/L Winter Biochemical 5.0 mg/L Summer 5.0 mg/L Summer Oxygen Demand 260 mg/L 250 mg/L 2043 Ib/day (BODS) 5.0 mg/L Winter 10.0 mg/L Winter Fecal Coliform 200 per 100 mL 200 per 100 mL Nitrate + Nitrite Nitrogen (NO3-N + N/A N/A NO2-N) Total Kjeldahl N/A mg/L Nitrogen N/A N/A Total Nitrogen N/A N/A N/A N/A Total Phosphorus N/A N/A N/A N/A N/A Total Suspended 136 mg/L 250 mg/L 2043 Ib/day 30.0 mg/L 30.0 mg/L Solids (TSS) 3. Based on the "Project Basis of Design" parameters listed above, will the proposed design allow the treatment facility to meet the NPDES Permit Limits listed above? ® Yes or ❑ No. If no, describe how and why the Permit Limits will not be met: Application for Authorization to Construct Permit (FORM ATC -12-14) Page 7 Water Resources ENVIRONMENTAL QUALITY State of North Carolina Department of Environmental Quality Division of Water Resources APPLICATION FOR AUTHORIZATION TO CONSTRUCT PERMIT (FORM ATC -12-14) 4. Per 15A NCAC 02T .0505(i), by-pass and overflow lines are prohibited. Is this condition met by the design? ® Yes or ❑ No If no, describe the treatment units bypassed, why this is necessary, and where the bypass discharges: 5. Per 15A NCAC 02T .0505(k), multiple pumps shall be provided wherever pumps are used. Is this condition met by the design? ® Yes or ❑ No. If no, provide an explanation: 6. Per 15A NCAC 02T .0505(1), power reliability shall be provided consisting of automatically activated standby power supply onsite capable of powering all essential treatment units under design conditions, or dual power supply shall be provided per 15A NCAC 02H. 0124(2)(a). Is this condition met by the design? ® Yes or ❑ No. If no, provide (as an attachment to this Application) written approval from the Director that the facility: ➢ Has a private water supply that automatically shuts off during power failures and does not contain elevated water storage tanks, and ➢ Has sufficient storage capacity that no potential for overflow exists, and ➢ Can tolerate septic wastewater due to prolonged detention. 7. Per 15A NCAC 02T .0505(0), a minimum of 30 days of residual storage shall be provided. Is this condition met by the design? ® Yes or ❑ No. If no, explain the alternative design criteria proposed for this project in accordance 15A NCAC 02T .105(n): 8. Per 15A NCAC 02T .0505(8), the public shall be prohibited from access to the wastewater treatment facilities. Explain how the design complies with this requirement: The property is enclosed within a locked fence. 9. Is the treatment facility located within the 100 -year flood plain? ® Yes or ❑ No. If yes, describe how the facility is protected from the 100 -year flood: The existing facility was built in a flood plain. All new structures are built outside of the flood plain where possible. C. WASTEWATER TREATMENT UNIT AND MECHANICAL EQUIPMENT INFORMATION —COMPLETE FOR NEW OR EXPANDING FACILITIES AND FOR MODIFIED TREATMENT UNITS 1. PRELIMINARY AND PRIMARY TREATMENT (i.e., physical removal operations and flow equalization): Application for Authorization to Construct Permit (FORM ATC -12-14) Page 8 No. of Plan Sheet Specification Calculations Treatment Unit Units Type Size per Unit Reference Reference Provided? (Yes or No) Manual Bar Screen 1 Manual 3.43 MGD at peak hourly flow M-1— M-2 462100 N/A Mechanical Bar 1 Rake 3.43 MGD at peak hourly flow M-1— M-2 462100 No Screen Grit Removal N/A MGD at peak hourly flow Flow Equalization N/A -- gallons Primary Clarifier N/A Circular ft diameter; ft side water depth Primary Clarifier N/A Rectangular square feet; ft side water depth Other N/A Application for Authorization to Construct Permit (FORM ATC -12-14) Page 8 Water Resources ENVIRONMENTAL QUALITY State of North Carolina Department of Environmental Quality Division of Water Resources APPLICATION FOR AUTHORIZATION TO CONSTRUCT PERMIT (FORM ATC -12-14) 2. SECONDARY TREATMENT (BIOLOGICAL REACTORS AND CLARIFIERS) (i.e., biological and chemical processes to remove organics and nutrients) 3. TERTIARY TREATMENT No. of Plan Sheet Specification Calculations Treatment Unit Units Type Size per Unit Reference Reference Provided? (Yes or No) Aerobic Zones/ N/A Circular gallons Tanks (Parallel; in side water depth Anoxic Zones/ N/A Rectangular gallons Tanks side water depth Anaerobic N/A (Gas; gallons Zones Tanks N/A tablet; liquid) square feet Sequencing Batch N/A -- gallons Reactor (SBR) N/A -- gallons Membrane N/A -- gallons Bioreactor (MBR) N/A gallons Secondary Clarifier 2 Circular 60 ft diameter; 14 ft side M-3 — M-4 46 43 00 Yes water depth Secondary Clarifier N/A Rectangular square feet; ft side water depth Other 3. TERTIARY TREATMENT 4. DISINFECTION No. of Plan Sheet Specification Calculations Treatment Unit Units Type Size per Unit Reference Reference Provided? (Yes or No) Tertiary Clarifier N/A Circular ft diameter; ft Ultraviolet Light (Parallel; in side water depth Tertiary Clarifier N/A Rectangular square feet; ft side water depth Tertiary Filter N/A (Gas; square feet Tertiary Membrane N/A tablet; liquid) square feet Filtration Post -Treatment N/A -- gallons Flow Equalization Post -Aeration N/A gallons Other 4. DISINFECTION Application for Authorization to Construct Permit (FORM ATC -12-14) Page 9 No. of Plan Sheet Specification Calculations Treatment Unit Units Type Size per Unit Reference Reference Provided? (Yes or No) gal/day per bank at Ultraviolet Light (Parallel; in peak hourly flow;number series) of banks; number of lamps/bank Chlorination (Gas; gallons of contact tablet; liquid) tank/unit Application for Authorization to Construct Permit (FORM ATC -12-14) Page 9 Water Resources ENVIRONMENTAL QUALITY State of North Carolina Department of Environmental Quality Division of Water Resources APPLICATION FOR AUTHORIZATION TO CONSTRUCT PERMIT (FORM ATC -12-14) Dechlorination No. of (Gas; gallons of contact Plan Sheet Specification Calculations Treatment Unit Units tablet; liquid) tank/unit Reference Reference Provided? S. RESIDUALS TREATMENT 6. PUMP SYSTEMS (include influent, intermediate, effluent, major recycles, waste sludge, thickened waste sludge and plant drain pumps) Location No. of purpose Type Plan Sheet Specification Calculations Treatment Unit Units Type Size per Unit Reference Reference Provided? 16.3 M-5 — M-7 43 25 13 Sludge Pump Station 2 Waste Sludge (Yes or No) Gravity Thickening N/A M-5 — M-7 square feet; ft side Sludge Pump Station 2 Scum Tank 122 24.2 water depth 43 24 16 Sludge Thickening Bldg. 1 Mechanical Dry 100 11.2 M-10 467133 Yes Thickening/ 1 Rotary Drum 59 dry Ib/hour M-8 — M-10 467133 Dewatering Aerobic Digestion 1 253,662 gallons M -11-M-13 N/A Yes Anaerobic N/A gallons Digestion Composting N/A dry Ib/hour Drying N/A dry Ib/hour Other 6. PUMP SYSTEMS (include influent, intermediate, effluent, major recycles, waste sludge, thickened waste sludge and plant drain pumps) Location No. of Pumps purpose Type Capacity of each pump Plan Sheet Reference Specification Reference GPM TDH Sludge Pump Station 4 Return Sludge Submersible 230 16.3 M-5 — M-7 43 25 13 Sludge Pump Station 2 Waste Sludge Submersible 125 24.8 M-5 — M-7 43 25 13 Sludge Pump Station 2 Scum Recirculating 122 24.2 M-5 — M-7 43 24 16 Sludge Thickening Bldg. 1 Thickened Waste Sludge Dry 100 11.2 M-10 467133 7. MIXERS Location No. of Mixers Purpose Type Power of each MP ixer plan Sheet Reference Specification Reference Application for Authorization to Construct Permit (FORM ATC -12-14) Page 10 Water Resources ENVIRONMENTAL QUALITY 8. BLOWERS State of North Carolina Department of Environmental Quality Division of Water Resources APPLICATION FOR AUTHORIZATION TO CONSTRUCT PERMIT (FORM ATC -12-14) Location No. of Blowers purpose Type Capacity of each Blower (CFM) plan Sheet Reference Specification Reference Blower Pad 3 Aerobic Digestion Positive Displacement 516 M-14 43 10 00 Below Any habitable residence or place of assembly under separate 100 ft ® Yes ❑ No ownership or not to be maintained as part of the project site Any private or public water supply source 100 ft ® Yes ❑ No Surface waters (streams — intermittent and perennial, perennial 50 ft ®Yes ❑ No waterbodies, and wetlands) Any well with exception of monitoring wells 100 ft ® Yes ❑ No Any property line 50 ft ® Yes 9. ODOR CONTROL Location No. of Units Purpose Type Plan Sheet Reference Specification Reference Setback Parameter Treatment/Storage Design? If "No", identify Unit Setback Waivers in Item D.2 Below Any habitable residence or place of assembly under separate 100 ft ® Yes ❑ No ownership or not to be maintained as part of the project site Any private or public water supply source D. SETBACKS— COMPLETE FOR NEW WASTEWATER TREATMENT STRUCTURES 1. The minimum distance for each setback parameter to the wastewater treatment/storage units per 15A NCAC 02T .0506(b) are as follows: Have any setback waivers been obtained per 15A NCAC 02T .0506(d)? ❑ Yes or ® No. If yes, have these waivers been written, notarized and signed by all parties involved and recorded with the County Register of Deeds? ❑ Yes or ❑ No. If no, provide an explanation: Application for Authorization to Construct Permit (FORM ATC -12-14) Page 11 Minimum Distance Is Minimum Distance Required from Nearest Requirement met by the Setback Parameter Treatment/Storage Design? If "No", identify Unit Setback Waivers in Item D.2 Below Any habitable residence or place of assembly under separate 100 ft ® Yes ❑ No ownership or not to be maintained as part of the project site Any private or public water supply source 100 ft ® Yes ❑ No Surface waters (streams — intermittent and perennial, perennial 50 ft ®Yes ❑ No waterbodies, and wetlands) Any well with exception of monitoring wells 100 ft ® Yes ❑ No Any property line 50 ft ® Yes ❑ No Have any setback waivers been obtained per 15A NCAC 02T .0506(d)? ❑ Yes or ® No. If yes, have these waivers been written, notarized and signed by all parties involved and recorded with the County Register of Deeds? ❑ Yes or ❑ No. If no, provide an explanation: Application for Authorization to Construct Permit (FORM ATC -12-14) Page 11 State of North Carolina Nl-' ,, Department of Environmental Quality Division of Water Resources a- WaterResources ENVIRONMENTAL QUALITY APPLICATION FOR AUTHORIZATION TO CONSTRUCT PERMIT (FORM ATC -12-14) SECTION 5: APPLICATION CERTIFICATION BY PROFESSIONAL ENGINEER Professional Engineer's Certification per 15A NCAC 02T.0105: I, Charles A. Willis Jr., P.E., BCEE, attest that this application package for an Authorization to Construct (Typed Name of Professional Engineer) for the Dutchman's Creek WWTP Renovation (Facility and Project Name) was prepared under my direct supervisory control and to the best of my knowledge is accurate, complete and consistent with the information supplied in the engineering plans, specifications, calculations, and all other supporting documentation for this project. I further attest that to the best of my knowledge the proposed design has been prepared in accordance with all applicable regulations and statutes, 15 NCAC 02H. 0100, 15A NCAC 02T, North Carolina General Statute 133-3, North Carolina General Statute 143-215.1, and Division of Water Resources Minimum Design Criteria for NPDES Wastewater Treatment Facilities, and this Authorization to Construct Permit Application, except as provided for and explained in Section 4.13.1 of this Application. I understand that the Division of Water Resources' issuance of the Authorization to Construct Permit may be based solely upon this Certification and that the Division may waive the technical review of the plans, specifications, calculations and other supporting documentation provided in this application package. I further understand that the application package may be subject to a future audit by the Division. Although certain portions of this submittal package may have been prepared, signed and sealed by other professionals licensed in North Carolina, inclusion of these materials under my signature and seal signifies that I have reviewed the materials and have determined that the materials are consistent with the project design. I understand that in accordance with General Statutes 143-215.6A and 143-215.66, any person who knowingly makes any false statement, representation, or certification in any application package shall be guilty of a Class 2 misdemeanor, which may include a fine not to exceed $10,000, as well as civil penalties up to $25,000 per violation. North Carolina Professional Engineer's seal with written signature placed over or adjacent to the seal and dated: `q%%0111111119deA . N CAR .Z. p . ��SS�O ° a � v z �EAt- 17710 Application for Authorization to Construct Permit (FORM ATC -12-14) Page 12 SECTION 6: APPLICATION CERTIFICATION BY APPLICANT Applicant's Certification per 15A NCAC 02T .0106(b): I, Leonard Barefoot, Interim Town Manager, attest that this application package for an Authorization to Construct (Typed Name of Signature Authority and Title) for the Dutchman's Creek WWTP Renovation Proiect (Facility and Project Name) has been reviewed by me and is accurate and complete to the best of my knowledge. I also understand that if all required parts of this application package are not completed and that if all required supporting information and attachments are not included, this application package will be returned to me as incomplete. I further certify that in accordance with 15A NCAC 02T .0120(b), the Applicant or any affiliate has not been convicted of environmental crimes, has not abandoned a wastewater facility without proper closure, does not have an outstanding civil penalty where all appeals have been abandoned or exhausted, are compliant with any active compliance schedule, and does not have any overdue annual fees. I understand that the Division of Water Resources' issuance of the Authorization to Construct Permit may be based solely upon acceptance of the Licensed Professional Engineer's Certification contained in Section 5, and that the Division may waive the technical review of the plans, specifications, calculations and other supporting documentation provided in this application package. I further understand that the application package may be subject to a future audit. I understand that in accordance with General Statutes 143-215.6A and 143-215.613 any person who knowingly makes any false statement, representation, or certification in any application package shall be guilty of a Class 2 misdemeanor, which may include a fine not tso�exceed $10,000, as well as civil penalties up to $25,000 per violation. Signature: v 5 lir Date: 64 THE COMPLETED APPLICATION AND SUPPORTING INFORMATION SHALL BE SUBMITTED TO: NORTH CAROLINA DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES DIVISION OF WATER RESOURCES/NPDES By U.S. Postal ServiceBy Courier/Special Delivery: 1617 MAIL SERVICE CENTER 512 N. SALISBURY STREET, 9TH FLOOR RALEIGH, NORTH CAROLINA 27699-1617 RALEIGH, NORTH CAROLINA 27604 TELEPHONE NUMBER: (919) 807-6389 Application for Authorization to Construct Permit (FORM ATC -12-14) Page 13 t HCDE NR North Carolina Department of Environment and Natural Resources Division of Water Resources Pat McCrory Governor October 6, 2014 Ms. Christine Bralley, Town Manager Town of Mocksville 171 Clement St. Mocksville, NC 27028 Subject: Final NPDES Permit Permit NCO021491 Dutchman Creek WWTP Davie County Class III Facility Dear Ms. Bralley: John E. Skvarla, III Secretary Division personnel have reviewed and approved your application for renewal of the subject permit. Accordingly, we are forwarding the attached NPDES permit. This permit is issued pursuant to the requireinents of North Carolina General Statute 143-215.1 and the Memorandum of Agreement between North Carolina and the U.S. Environmental Protection Agency dated October 15, 2007 (or as subsequently amended). The final permit contains the following changes from the draft permit: A Nutrient Reopener Special Condition was added to the peri -nit to address a future TMDL or management strategy for High Rock Lake. See Special Condition A.(5). The final permit contains the following changes from your previous permit: As a result of a Reasonable Potential Analysis (RPA) monitoring for cyanide was eliminated from your permit monitoring requirements. The acute cadmium limit was incorrectly expressed in the draft permit as a weekly average limit, the limit should be a daily maximum limit as in your previous permit. This correction is reflected in your final permit. 1601 Mail Service Center, Raleigh, North Carolina 27699-1601 Phone: 919-707-86001 Internet: www.ncdenr.gov An Equal Opportunity I Affirmative Action Employer— Made in part by recycled paper Ms. Bralley October 6, 2014 Page 2 of 2 • Monitoring for copper, silver and zinc was modified to quarterly according to the Division's monitoring frequency guidance for metals. • The requirement to perform effluent pollutant scans was modified from annual to three times during your permit cycle. See Special Condition A.(3). This condition also includes requirements for toxicity testing with alternate species. • The permit includes a Special Condition [See Part I, A. (4.)] to address the Environmental Protection Agency's (EPA's) pending requirement for you to provide electronically - submitted Discharge Monitoring Reports (eDMRs). If any parts, measurement frequencies or sampling requirements contained in this permit are unacceptable to you, you have the right to an adjudicatory hearing upon written request within thirty (30) days following receipt of this letter. This request must be in the form of a written petition, conforming to Chapter 150B of the North Carolina General Statutes, and filed with the Office of Administrative Hearings (6714 Mail Service Center, Raleigh, North Carolina 27699-6714). Unless such demand is made, this decision shall be final and binding. Please note that this permit is not transferable except after notice to the Division. The Division may require modification or revocation and reissuance of the permit. This permit does not affect the legal requirements to obtain other permits which may be requited by the Division of Water Resources or permits required by the Division of Land Resources, the Coastal Area Management Act or any other federal or local governmental permits that may be required. If you have` any questions concerning this permit, please contact Teresa Rodriguez at telephone number (919) 807-6387 or at email Teresa.rod.tiguez@ncdenr.gov. SYerely, ornas A. Reeder, Director Division of Water Resources, NCDENR cc: NPDES Files Central files Envirolink, Ms. Heather Adams, PO Box 670, Bailey, NC 27807 Winston Salem Regional Office / Surface Water Protection Section (e -copy) Aquatic Toxicology Branch, Susan Meadows (e -copy) Ecosystems Branch, Carrie Ruhhzran (e -copy) Permit NCO021491 STATE OF NORTH CAROLINA DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES DIVISION OF WATER RESOURCES TO DISCHARGE WASTEWATER UNDER THE NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM In compliance with the provisions of North Carolina General Statute 143-215.1, other lawful standards and regulations promulgated and adopted by the North Carolina Environmental Management Commission, and the Federal Water Pollution Control Act, as amended, the Town of Mocksville is hereby authorized to discharge wastewater from a facility located at the Dutchman Creek WWTP 295 Garwood Road Mocksville Davie County to receiving waters designated as Dutchman Creek in the Yadkin -Pee Dee River Basin in accordance with effluent limitations, monitoring requirements, and other conditions set forth in Parts I, II, III, and IV hereof. The permit shall become effective November 1, 2014. This permit and the authorization to discharge shall expire at midnight on June 30, 2019. Signed this day October 6, 2014. G t t Thomas A. Reeder, Director Division of Water Resources By Authority of the Environmental Management Commission Page I of 8 Permit NCO021491 SUPPLEMENT TO PERMIT COVER SHEET All previous NPDES Permits issued to this facility, whether for operation or discharge are hereby revoked. As of this permit issuance, any previously issued permit bearing this number is no longer effective. Therefore, the exclusive authority to operate and discharge from this facility arises under the permit conditions, requirements, terms, and provisions included herein. The Town of Mocksville is hereby authorized to: 1. Continue to operate the existing 0.98 MGD wastewater treatment system that includes the following components: ➢ Flow splitter box ➢ Mechanical fine screening 9 Grit removal ➢ Flow measurement ➢ Three aeration basins ➢ Three secondary clarifiers 9 Chlorination and dechlorination units 9 Sludge recirculation and wasting ➢ Aerobic digester ➢ Emergency generator This facility is located at the Dutchman s Creek WWTP (295 Garwood Road, Mocksville) in Davie County. 2. Discharge from said treatment works at the location specified on the attached map into Dutchman Creek, classified C waters in the Yadkin -Pee Dee River Basin. Page 2 of 8 Permit NCO021491 A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS During the period beginning on the effective date of the permit and lasting until permit expiration, the Permittee is authorized to discharge from outfall 001. Such discharges shall be limited and monitored6 by the Permittee asspecified below: EFFLUENT LIMITS MONITORING REQUIREMENTS „ Monthly Weekly .. Daily Measurement Sample : Sample CHARACTERISTICS . Avera- e " : Avera "e Maximum', : .Fre `ueh Te_:., ,Locaf ori?,:. Flow 0.98 MGD Continuous Recording I or E BOD5 20 °C2 5.0 mg/1 7.5 mg/l 3/Week Composite LE (April 1- October 30) BOD5 20 °C2 10.0 mg/L 15.0 mg/L 3/Week Composite I, E (November 1- March 31) Total Suspended Solids2 30.0 mg/l 45.0 mg/l 3/Week Composite 1, E Temperature Daily Grab E, U, D Dissolved Oxygen 3/Week Grab E, U, D Fecal Coliform 200 / 100 ml 400 / 100 ml 3/Week Grab E (geometric mean) NH3 as N 2.0 mg/l 6.0 mg/l 3/Week Composite E (April 1- October 30 NH3 as N (winter) 4.0 mg/L 12.0 mg/L 3/Week Composite E November 1 - March 31 Total Nitrogen (NO2 + NO3 + TKN) Quarterly Composite E Total Phosphorus Quarterly Composite E H 6.0 - 9.0 standard units 3/Week Grab E Total Residual Chlorine 28µg/1 2/Week Grab E Chronic Toxici s Quarterly Composite E Cadmium 5.3 µ /l 36 pg/1 Monthly Composite E Copper Quarterly Composite E Zinc Quarterly Composite E Silver Quarterly Composite E Effluent Pollutant Scan Monitor and Report Footnote 7 Footnote 7 E Notes: 1. I= Influent. E= Effluent. U= Upstream approximately 100 feet upstream from the outfall. D= Downstream approximately 0.5 miles downstream from the outfall. Upstream and downstream samples shall be grab samples collected 3/week during June, July, August, and September and once per week during the rest of the year. As a participant in the Yadkin Pee -Dee River Basin Association, the subject facility is not responsible for conducting the instream monitoring requirements as stated above. Should your membership in the agreement be terminated, you shall notify the Division immediately and the instream monitoring requirements specified in your permit will be automatically reinstated. 2. The monthly average effluent BOD5 and Total Suspended Solids concentrations shall not exceed 15 percent of the respective influent value (85 % removal). 3. The daily average dissolved oxygen effluent concentration shall not be less than 6.0 mg/1 from April 1 to October 31, and no less than 5.0 mg/L.from November 1 to March 31. 4. The Division shall consider all effluent total residual chlorine values reported below 50 µg/l to be in compliance with the permit. However, the Permittee shall continue to record and submit all values reported by a North Carolina certified laboratory (including field certified), even if these values fall below 50 gg/l. 5. Chronic Toxicity (Ceriodaphnia) at 37%: January, April, July, and October (see condition A. (2.)). 6. No later than 270 days from the effective date of this permit, begin submitting discharge monitoring reports electronically using NC DWWs eDMR application system. See Special Condition A (4). 7. The permittee shall perform three Effluent Pollutant Scans during the term of this permit [see A. (3)]. Page 3 of 8 Permit NCO021491 There shall be no discharge of floating solids or visible foam in other than trace amounts. A. (2.) QUARTERLY CHRONIC TOXICITY PERMIT LIMIT The effluent discharge shall at no time exhibit observable inhibition of reproduction or significant mortality to Ceriodaphnia dubia at an effluent concentration of 37%. The permit holder shall perform at a minimum, quarterli monitoring using test procedures outlined in the "North Carolina Ceriodaphnia Chronic Effluent Bioassay Procedure," Revised December 2010, or subsequent versions or "North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure" (Revised- December 2010) or subsequent versions. The tests will be performed during the months of January, April, July, and October. These months signify the first month of each three-month toxicity testing quarter assigned to the facility. Effluent sampling for this testing must be obtained during representative effluent discharge and shall be performed at the NPDES permitted final effluent discharge below all treatment processes. If the test procedure performed as the first test of any single quarter results in a failure or ChV below the permit limit, then multiple -concentration testing shall be performed at a minimum, in each of the two following months as described in "North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure" (Revised -December 2010) or subsequent versions. All toxicity testing results required as part of this permit condition will be entered on the Effluent Discharge Monitoring Form (MR -1) for the months in which tests were performed, using the parameter code TGP3B for the pass/fail results and THP3B for the Chronic Value. Additionally, DWR Form AT -3 (original) is to be sent to the following address: Attention: North Carolina Division of Water Resources Water Sciences Section/Aquatic Toxicology Branch 1621 Mail Service Center Raleigh, North Carolina 27699-1621 Completed Aquatic Toxicity Test Forms shall be filed with the Water Sciences Section no later than 30 days after the end of the reporting period for which the report is made. Test data shall be complete, accurate, include all supporting chemical/physical measurements and all concentration/response data, and be certified by laboratory supervisor and ORC or approved designate signature. Total residual chlorine of the effluent toxicity sample must be measured and reported if chlorine is employed for disinfection of the waste stream. Should there be no discharge of flow from the facility during a month in which toxicity monitoring is required, the permittee will complete the information located at the top of the aquatic toxicity (AT) test form indicating the facility name, permit number, pipe number, county, and the month/year of the report with the notation of "No Flow" in the comment area of the form. The report shall be submitted to the Water Sciences Section at the address cited above. Should the permittee fail to monitor during a month in which toxicity monitoring is required, monitoring will be required during the following month. Assessment of toxicity compliance is based on the toxicity testing quarter, which is the three month time interval that begins on the first day of the month in which toxicity testing is required by this permit and continues until the final day of the third month. Should any test data from this monitoring requirement or tests performed by the North Carolina Division of Water Resources indicate potential impacts to the receiving stream, this permit may be re -opened and modified to include alternate monitoring requirements or limits. NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum control organism survival, minimum control organism reproduction, and appropriate environmental controls, shall Page 4 of 8 Permit NCO021491 constitute an invalid test and will require immediate follow-up testing to be completed no later than the last day of the month following the month of the initial monitoring. A. (3) EFFLUENT POLLUTANT SCAN The Permittee shall perform a total of three (3) Effluent Pollutant Scans for all parameters listed below. One scan must be performed in each of the following years: 2015, 2016, and 2017. Analytical methods shall be in accordance with 40 CFR Part 136 and shall be sufficiently sensitive to determine whether parameters are present in concentrations greater than applicable standards and criteria. Samples should be collected with one quarterly toxicity test each year, and must represent seasonal variation [i.e., do not sample in the same quarter every year]. Unless otherwise indicated, metals shall be analyzed as "total recoverable." Ammonia (as N) Trans-1,2-dichloroethylene Bis (2-chloroethyl) ether Chlorine (total residual, TRC) 1,1-dichloroethylene Bis (2-chloroisopropyl) ether Dissolved oxygen 1,2-dichloropropane Bis (2-ethylhexyl) phthalate Nitrate/Nitrite 1,3-dichloropropylene 4-bromophenyl phenyl ether Kjeldahl nitrogen Ethylbenzene Butyl benzyl phthalate Oil and grease Methyl bromide 2-chloronaphthalene Phosphorus Methyl chloride 4-chlorophenyl phenyl ether Total dissolved solids Methylene chloride Chrysene Hardness 1,1,2,2 -tetrachloroethane Di -n -butyl phthalate Antimony Tetrachloroethylene Di-n-octyl phthalate Arsenic Toluene Dibenzo(a,h) anthracene Beryllium 1,1,1 -trichloroethane 1,2 -dichlorobenzene Cadmium 1,1,2 -trichloroethane 1,3 -dichlorobenzene Chromium Trichloroethylene 1,4 -dichlorobenzene Copper Vinyl chloride 3,3-dichlorobenzidine Lead Acid -extractable compounds: Diethyl phthalate Mercury (EPA Method 1631E) P -chloro -m -cresol Dimethyl phthalate Nickel 2 -chlorophenol 2,4-dinitrotoluene Selenium 2,4-dichlorophenol 2,6-dinitrotoluene Silver 2,4 -dimethylphenol 1,2-diphenylhydrazine Thallium 4,6-dinitro-o-cresol Fluoranthene Zinc 2,4-dinitrophenol Fluorene Cyanide 2-nitrophenol Hexachlorobenzene Total phenolic compounds 4-nitrophenol Hexachlorobutadiene Volatile organic compounds: Pentachlorophenol Hexachlorocyclo-pentadiene Acrolein Phenol Hexachloroethane Acrylonitrile 2,4,6 -trichlorophenol Indeno(1,2,3-cd)pyrene Benzene Base -neutral compounds: Isophorone Bromoform Acenaphthene Naphthalene Carbon tetrachloride Acenaphthylene Nitrobenzene Chlorobenzene Anthracene N-nitrosodi-n-propylamine Chlorodibromomethane Benzidine N-nitrosodimethylamine Chloroethane Benzo(a)anthracene N-nitrosodiphenylamine 2-chloroethylvinyl ether Benzo(a)pyrene Phenanthrene Chloroform 3,4 benzofluoranthene Pyrene Dichlorobromomethane Benzo(ghi)perylene 1,2,4-trichlorobenzene 1,1-dichloroethane Benzo(k)fluoranthene 1,2-dichloroethane Bis (2-chloroethoxy) methane Page 5 of 8 Permit NCO021491 Reporting. Test results shall be reported on DWR Form -A MR-PPA1 (or in a form approved by the Director) by December 31s' of each designated sampling year. The report shall be submitted to the following address: NC DENR/ DWR/ Central Files, 1617 Mail Service Center, Raleigh, North Carolina 27699-1617. A. (4) ELECTRONIC REPORTING OF DISCHARGE MONITORING REPORTS Proposed federal regulations require electronic submittal of all discharge monitoring reports (DMRs) and specify that, if a state does not establish a system to receive such submittals, then permittees must submit DMRs electronically to the Environmental Protection Agency (EPA). The Division anticipates that these regulations will be adopted and is beginning implementation in late 2013. NOTE: This special condition supplements or supersedes the following sections within Part H of this permit (Standard Conditions for NPDES Permits): • Section B. (11.) Signatory Requirements • Section D. (2.) Reporting • Section D. (6.) Records Retention • Section E. (5.) Monitoring Reports 1. Reporting rSupersedes Section D. (2.) and Section E. (5.) (a)1 Beginning no later than 270 days from the effective date of this permit, the permittee shall begin reporting discharge monitoring data electronically using the NC DWR's Electronic Discharge Monitoring Report (eDMR) internet application. Monitoring results obtained during the previous month(s) shall be summarized for each month and submitted electronically using eDMR. The eDMR system allows permitted facilities to enter monitoring data and submit DMRs electronically using the internet. Until such time that the state's eDMR application is compliant with EPA's Cross -Media Electronic Reporting Regulation (CROMERR), permittees will be required to submit all discharge monitoring data to the state electronically using eDMR and will be required to complete the eDMR submission by printing, signing, and submitting one signed original and a copy of the computer printed eDMR to the following address: NC DENR / DWR / Information Processing Unit ATTENTION: Central Files / eDMR 1617 Mail Service Center Raleigh, North Carolina 27699-1617 If a permittee is unable to use the eDMR system due to a demonstrated hardship or due to the facility being physically located in an area where less than 10 percent of the households have broadband access, then a temporary waiver from the NPDES electronic reporting requirements maybe granted and discharge monitoring data may be submitted on paper DMR forms (MR 1, 1.1, 2,3) or alternative forms approved by the Director. Duplicate signed copies shall be submitted to the mailing address above. Requests for temporary waivers from the NPDES electronic reporting requirements must be submitted in writing to the Division for written approval at least sixty (60) days prior to the date the facility would be required under this permit to begin using eDMR. Temporary waivers shall be valid for twelve (12) months and shall thereupon expire. At such time, DMRs shall be submitted electronically to the Division unless the permittee re -applies for and is granted a new temporary waiver by the Division. Information on eDMR and application for a temporary waiver from the NPDES electronic reporting requirements is found on the following web page: htW://portal.iicdenr.org/web/wq/""­adii-dn/­bog/"`ipu/edmr Page 6 of 8 Permit NC0021491 Regardless of the submission method, the first DMR is due on the last day of the month following the issuance of the permit or in the case of a new facility, on the last day of the month following the commencement of discharge. 2. Signatory Requirements [Supplements Section B. (11.) (b) and supersedes Section B. (11.) (d)j All eDMRs submitted to the permit issuing authority shall be signed by a person described in Part II, Section B. (11.)(a) or by a duly authorized representative of that person as described in Part II, Section B. (11.)(b). A person, and not a position, must be delegated signatory authority for eDMR reporting purposes. For eDMR submissions, the person signing and submitting the DMR must obtain an eDMR user account and login credentials to access the eDMR system. For more information on North Carolina's eDMR system, registering for eDMR and obtaining an eDMR user account, please visit the following web page: http://portal.ncdenr.org/web/wq/­admin/bog/­ipu/edmr Certification. Any person submitting an electronic DMR using the state's eDMR system shall make the following certification [40 CFR 122.22]. NO OTHER STATEMENTS OF CERTIFICATION WILL BE ACCEPTED: "I certifij, under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on nay inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fines and imprisonment far knowing violations. " 3. Records Retention [Supplements Section D. (6.)1 The permittee shall retain records of all Discharge Monitoring Reports, including eDMR submissions. These records or copies shall be maintained for a period of at least 3 years from the date of the report. This period may be extended by request of the Director at any time [40 CFR 122.41]. A. (5) Nutrient Reopener for High Rock Lake This permit may be reopened and modified to implement nutrient requirements in accordance with any future TMDL and/or nutrient management strategy for High Rock Lake. Page 7 of 8 Town of Mocksville Residual Management Plan Dutchman's Creek WWTP Renovation The Dutchman's Creek WWTP currently operates under a Land Application of Residual Solids (503) Permit for residual management. The proposed Dutchman's Creek WWTP Renovation project will significantly improve upon the facility's existing residual management strategy, eliminating all problematic components of the current design. Excess solids at Dutchman's Creek WWTP are currently treated in a single 176,000 gallon aerobic digester. The digester currently relies on a single mechanical aerator to keep the sludge well -mixed and aerated, but due to frequent malfunctions of this aerator, the operators are heavily reliant on lime stabilization to meet their Land Application requirements. The digester has fixed -elevation decanters that only have the ability to decant to two of the three aeration basins. Additionally, the digester has a drain that conveys sludge to truck loading station for hauling. There is no way to drain the digester without additional pumping. The proposed biosolids management process will add an additional aerobic digester to allow for a more efficient digestion process. Both the existing and new digester will be fitted with a telescoping valve that will allow the operator to decant residual water back to the influent pumping station of the WWTP. Each digester will also have a sludge drain that combine flows prior to the existing truck loading station, allowing a truck to haul sludge from either digester from a single location. Both digesters will be fitted with a diffused air system, eliminating the digestion inefficiencies caused by the faulty mechanical aerator. Upstream of the digestion process, a sludge thickener will be added to increase the solids content of the sludge prior to digestion. This sludge thicker will be accompanied by a polymer feed system, along with an intermediate pumping station to convey the thickened sludge to the digesters. A flow diagram for the facility's sludge management strategy is shown on page 2 of the Residual Management Plan. In addition to improved sludge management, the proposed Dutchman's Creek WWTP Renovation project will replace the existing problematic screening equipment in the influent pump station with a screen located in a new headworks structure to remove non-organic debris from the influent flow. The new screening unit will be a mechanical rake design with 6 mm screen openings. The unit will be equipped with a screw conveyor, spray wash system and compactor discharging the screened, washed material into a dumpster. A manual bar screen with 1 -inch bar spacing will also be provided in the event the primary screening unit is out of service or has failed to operate properly. The manually screened material will also be placed in the dumpster. The dumpster will be hauled off-site for disposal, as is currently done. Willis Engineers 1984.015 1 June 2018 w o Q °0 Q N F- Q z o F w U N Z F- z Ld J Lij 2i J Q C) O J C7 w F- V) C) LLJY � D FF- w p = U N < ( O N H U Z a z Q J Ld z � W w � U � W C� 0 U Q z J J � U) Q Z�W �0w p z dow o z z Q v~iow XOC� Oro Q 0 J woo ago N Q O = Q N CD V)U CL 2 D W WCL F- a W z w F z N W J w J z - w z r m o - 0 0 wZ� CD � ~ (fM) 0WHY W U �y} w o W N=N W F z w o LD U z W bl Ld w L, NO1103JNISI0 01 M0I3 Of g z Z m m z O a Ld w Q M O K w 3 O J li VLL0--A ON 'OIC ON - LLZ8Z VNI]ONVO H121ON '31iMIVHO '30V1d S3AIS OOLOI 'ONI Sa33NION3 SI-1-11M Engineering Calculations Wastewater Facilities Contract 11.0 Dutchman's Creek WWTP Renovation CWSRF Project No. CS370606-02 WONI1SENGINEERS 10700 Sikes Place, Suite 115 Charlotte, North Carolina 28277 North Carolina License No. F-0114 TOWN OF MOCKSVILLE WATERWATER FACILITIES CONTRACT 11.0 — DUTCHMAN'S CREEK WWTP RENOVATION DESIGN CALCULATIONS TABLE OF CONTENTS 1 Influent Design Criteria 2 Peaking Factor Calculation 3-6 Basis of Design 7 Diffuser Quantity Calculation 8-9 Blower Requirements 10-13 Return Activated Sludge (RAS) System Head Development 14-16 Waste Activated Sludge (WAS) System Head Development 17-19 Scum System Head Development 20-25 Buoyancy Calculations 26-27 Sludge Thickener Requirements 28 Load Tabulation Willis Engineers i 1984.015 June 2018 Town of Mocksville Dutchman's Creek WWTP Renovation Influent Design Criteria The influent parameters in our Basis of Design was based on the median value of the 30 -day rolling average of several years of Plant DMR data. Because there are several measurements with extreme outliers (likely due to sampling error), using the median instead of the mean values provides a better indication of the central tendency for the Dutchman's Creek WWTP influent design constituents. The selected influent design parameters are similar to those for the previous plant projects, as well as those used by the original equipment manufacturers. Below is the table summarizing the design parameters. The design loading was calculated as follows: Loading = 8.34 x Flow in MGD x Concentration in mg/L Dutchman's Creek Historical (mg/0 Design Selection (mg/0 BOD 216 250 TSS 210 250 The design loading was calculated as follows: Loading = 8.34 x Flow in MGD x Concentration in mg/L Willis Engineers 1984.015 1 June 2018 Design Selection (lbs/day) BOD 2043 TSS 2043 Willis Engineers 1984.015 1 June 2018 Town of Mocksville Dutchman's Creek WWTP Renovation Assumptions Qcoi Avg Flow at Cooleemee WWTP QDutch Avg Flow at Dutchman's Creek WWTP p Avg People Per Household S Mocksville Total Service Connections PDUtch Dutchman's Creek Served Population, Thousands PF Peaking Factor Formulas PDUtch Dutchman's Creek Served Population PF Peaking Factor Calculations PDutch Dutchman's Creek Served Population PF Peaking Factor Peaking Factor Calculation 221,700 gpd 452,000 gpd 2.6 people/house 2419 Connections X Thousand People X S x QDutch/(Qcoi + QDutch) x p/1000 (18 + PDutch1/z)/(4+PDutchl/2) 4.22 Thousand People 3.3 Say 3.5 Willis Engineers 1984.015 2 June 2018 Town of Mocksville Dutchman's Creek WWTP Renovation Design Parameters: Influent Design Daily Flow Peak Hourly Flow BOD (5 -day) Total Suspended Solids Effluent (summer limits): BOD (5 day) Weekly Monthly Total Suspended Solids Weekly Monthly Plant and Process Facilities Note: Plant upgrades are shown in RED Basis of Design 980,000 gpd 3,430,000 gpd 250 mg/I 250 mg/I 7.5 mg/I 5 mg/I 45 mg/I 30 mg/I 1 Influent Pumping Station Pump Number 3 Type Submersible, Non -Clog Pump Capacity, each 1,150 gpm Drive Size, each 30 HP Force Main 8 inch transitions to 12 inch at by-pass connection Diameter 8 in Length 49 ft Diameter 12 in Length 270 ft 2 Headworks Replace Screening Equipment in new headworks facility Screening Type Manual Bypass Quantity 1 Width 3 feet Spacing 1 in Capacity 2382 gpm Type Mechanical Rake Quantity 1 Width 3 feet Spacing 6 mm Capacity 2382 gpm Drive 2 HP Washer/Conveyor 5 HP Willis Engineers 1984.015 3 June 2018 Town of Mocksville Basis of Design Dutchman's Creek WWTP Renovation 3 Extended Aeration Basins Number 3 Volume, each 340,000 gallons Volume, Total for Plant 1,020,000 gallons Detention 25 hours Floating Aerators (total for plant) Number 2 per basin Motor 25 HP 4 Secondary Clarification Construct new clarifiers sized to current industry standards Number 2 Recycle Ratio 1 Max Allowable Avg Solid Loading Rate 20 Ibs/ft^2/day Max Allowable Peak Solid Loading Rate 35 Ibs/ft^2/day Max Allowable Hydraulic Loading 1000 gpd/ft^2 Average Solid Loading Rate 40866 lbs/clay/clarifier Peak Solid Loading Rate 91,948.50 lbs/clay/clarifier Hydraulic Loading Rate 1715000 gpd/clarifier Avg Solid Loading Area 2043.3 ft^2 Peak Solid Loading Area 2,627.10 ft^2 Peak Hydraulic Area 1715 ft^2 Solids Loading Diameter 51 ft Peak Solid Loading Diameter 58 ft Hydraulic Loading Diameter 47 ft Selected Diameter 58 ft Depth 14 ft Volume (each) 275,110 gallons Willis Engineers 1984.015 4 June 2018 Town of Mocksville Basis of Design Dutchman's Creek WWTP Renovation 5 Process Pumps New RAS and WAS pump station; add chopper pumps for scum management RAS Number 4 total Type Submersible Recycle Flow 230 GPM Each Drive Size, Each 7.5 HP WAS Number 2 Total Type Submersible Wasting Rate 125 GPM each Drive Size, Each 3 HP Scum Number 2 Type Chopper Capactiy 122 GPM Drive Size, Each 10 HP Thickened Sludge Number 1 Type Dry Capactiy 100 GPM Drive Size, Each 3 HP 6 Sludge Thickening Add sludge thicking to increase aerobic digester retention time and sludge storage Solids Thickening Achievable 4 Type Rotary Drum Drive Size 3 HP Dry Capacity 59 lbs/hr Willis Engineers 1984.015 5 June 2018 Town of Mocksville Dutchman's Creek WWTP Renovation Basis of Design 7 Aerobic Digester Basin Add new digester and replace existing mechanical aerator with diffused air Existing Number 1 Tank Diameter 50 ft Depth 12 ft Volume (New) 176,154 gallons HRT/SRT @ Average Flow 46 days HRT/SRT @ 80% Design Flow 27 days Aeration Aeration Requirement Flow New Number Diameter Depth HRT/SRT @ Average Flow HRT/SRT @ 80% Design Flow Volume (New) Aeration Aeration Requirement Flow Blowers Number Type Capacity Drive Size, Each 8 Disinfection Type Number of Basins Chlorine Contact Dechlorination Contact 25 CFM/1000 CF 589 SUM 1 Tank 60 ft 12 ft 66 days 40 days 253,662 gallons 25 CFM/1000 CF 848 SUM 3 Positive Displacement 516 SUM 20 HP Chlorine Contact and Dechlorination 2 5,000 cf/basin 160 cf/basin Willis Engineers 1984.015 6 June 2018 Town of Mocksville Diffuser Quantity Calculation Dutchman's Creek WWTP Renovation Blowers Air Per Blower 516 SUM Quantity 3 Existing Aerobic Digester Air Required 589 SUM Air Available 634 SUM Max Air per Diffuser 15 SUM Total Diffusers 39.3 Diffusers As Drawn 52 Diffusers Length of Air Piping per side 112.5 Feet Diffuser Spacing 4.3 Feet Actual Air per Diffiser 12.2 SUM New Aerobic Digester Air Required 848 SUM Air Available 914 SUM Max Air per Diffuser 15 SUM Total Diffusers 56.5 Diffusers As Drawn 70 Diffusers Length of Air Piping per side 314 Feet Diffuser Spacing 4.5 Feet Actual Air per Diffiser 13.1 SUM Willis Engineers 1984.015 7 June 2018 Town of Mocksville Dutchman's Creek WWTP Aeration Piping Headloss Scenario: Both Digesters Online Blower Requirements Willis Engineers 1984.015 8 June 2018 Design Flow 1548 SCFM Altitude/Temp Adjustment 1.05 Submerged Depth of Discharge 11.2 ft Static HL 4.8 psi Static+Friction HL 5.79 psi Air per Diffuser 13.1 SCFM Diameter Length Equivalent Length HL Total Segment SCFM HL per 100 ft (in) (ft) of Fittings (ft) (in) Al 8 81 118 1548 2.8 5.57 A2 6 10 33 914 5.1 2.19 A3 6 40 63 914 5.1 5.23 a 6 8 30 835 4.5 1.71 b 6 8 30 705 3 1.14 c 6 8 30 548 2 0.76 d 6 8 30 365 0 0.00 e 6 8 30 208 0.75 0.29 f 6 8 30 78 0.05 0.02 g 3 2.25 22 39 0.01 0.00 h 3 4.5 22 26 0.005 0.00 1 3 4.5 22 13 0.005 0.00 j Diffuser - - 13 - 8.20 IHL (in) 25.1 FHL (psi) 0.91 Willis Engineers 1984.015 8 June 2018 D m ® ❑ D Z � 00 Q Z ❑ CA W ® D Z El m z G I I I z II m f z 01 m OD N II WAC ���^ V, N0 II �ZC) �C II zm _0 m Z 0 CA D ON D m z Crl ` D =-9 D CO C r' -9 F— �c m = O 0 m 0 A \� Z7 D z m mCA z O Fj O N n Ci o m m N m0 F-9 fTl G A � � r Z � m awm K: 0 Cf) O CA :E A m A _ D C r_ Cf)D C z m o j C z c� m m cn N m O a7 W m Town of Mocksville Dutchman's Creek WWTP Narrative: A system head curve for the new RAS recycle pumps System Configuration Top of Wetwell 663.50 ft MSL Wetwell Bottom 648.50 ft MSL Water Level 661.50 ft MSL Discharge 664.75 ft MSL Static Head 3.25 ft 25 20 w 10 5 0 0 RAS System Head Development Pump Discharge 4" Impeller 9.00" Motor 7.5 HP Pump Efficiency 67.00% 100 200 300 400 Flow (gpm) 70 60 50 40 30 io m Willis Engineers 1984.015 10 June 2018 i ♦ ♦ ♦ ♦ ♦ Fairbanks Nihjuis 5432 1 Pump System Head 3 Pump System Head — — Efficiency 100 200 300 400 Flow (gpm) 70 60 50 40 30 io m Willis Engineers 1984.015 10 June 2018 Town of Mocksville Dutchman's Creek WWTP Friction losses based on C Diameter (in) Length (ft) Sum K Q (gpm) 300 230 Q (gpm) 0 50 100 150 200 230 300 350 400 450 500 550 600 650 700 750 800 850 115 4 4 4 6 22 28 9 500 5.56 0.9 1.7 2.57 Hf Hm 1.6 5.1 1.0 3.0 Hf Hm 0.0 0.0 0.1 0.1 0.2 0.6 0.4 1.3 0.8 2.3 1.0 3.0 1.6 5.1 2.1 6.9 2.7 9.0 3.4 11.4 4.1 14.1 4.9 17.0 5.7 20.3 6.7 23.8 7.6 27.6 8.7 31.7 9.8 36.1 10.9 40.7 RAS System Head Development Hm Duty Point 0.1 14.9 Hf Hm Hf Hm Hf 2.0 0.8 0.2 0.2 1.7 1.2 0.5 0.1 0.1 1.0 Hf Hm Hf Hm Hf 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.0 0.0 0.1 0.3 0.1 0.0 0.0 0.2 0.6 0.2 0.1 0.0 0.5 1.0 0.4 0.1 0.1 0.8 1.2 0.5 0.1 0.1 1.0 2.0 0.8 0.2 0.2 1.7 2.7 1.1 0.3 0.2 2.2 3.5 1.5 0.4 0.3 2.9 4.3 1.8 0.5 0.4 3.6 5.2 2.3 0.6 0.5 4.3 6.2 2.8 0.7 0.6 5.2 7.3 3.3 0.8 0.7 6.0 8.5 3.9 0.9 0.8 7.0 9.7 4.5 1.0 0.9 8.0 11.0 5.1 1.2 1.1 9.1 12.4 5.8 1.3 1.2 10.3 13.9 6.6 1.5 1.4 11.5 RAS System Head Development Hm TDH 0.1 14.9 0.0 16.3 3 Pumps Hm TDH TDH 0.0 3.3 3 0.0 3.6 4 0.0 4.7 6 0.0 6.3 9 0.0 8.6 13 0.0 10.2 16 0.1 14.9 25 0.1 18.9 32 0.1 23.5 41 0.1 28.7 51 0.1 34.4 61 0.2 40.7 73 0.2 47.6 86 0.2 55.0 99 0.3 63.0 114 0.3 71.5 130 0.4 80.6 147 0.4 90.2 164 Willis Engineers 1984.015 11 June 2018 LL L TOWN OF MOCKSVILLE WIIIISENGINEERS DUTCHMAN'S CREEK WWTP RAS SYSTEM HEAD DEVELOPMENT JUNE 2018 19 SCALE PAGE 1'=5' 12 SS SS SS FTI a 0 e TOWN OF MOCKSVILLE JUNE 2018 OMEN WINISENGINEERS DUTCHMAN'S CREEK WWTP SCALE PAGE RAS SYSTEM HEAD DEVELOPMENT 1"=50' 13 Town of Mocksville Dutchman's Creek WWTP Narrative: A system head curve for the new WAS pumps System Configuration Motor Top of Wetwell 663.50 ft MSL Wetwell Bottom 642.50 ft MSL Water Level 661.50 ft MSL Discharge 679.70 ft MSL Static Head 18.20 ft 50 45 40 35 d x v 30 R C 0 25 0 20 15 10 5 0 0 WAS System Head Development Pump Impeller 5.81" Motor 2.00 Efficiency 46.00% Speed 1750 RPM 50 100 150 Flow (gpm) 100 90 80 70 60 w 50 y `m a 40 30 20 10 0 200 Willis Engineers 1984.015 14 June 2018 Town of Mocksville Dutchman's Creek WWTP Friction losses based on C = Diameter (in) Length (ft) Sum K Q (gpm) Hf 125 4.5 Q (gpm) Hf 0 0.0 50 0.8 100 3.0 150 6.4 200 10.8 250 16.4 300 22.9 350 30.5 400 39.1 450 48.6 500 59.0 550 70.4 600 82.7 650 95.9 700 110.0 750 125.0 800 140.8 850 157.5 900 175.1 950 193.5 1000 212.8 WAS System Head Development 115 4 6 317 268.45 7.85 8.95 Duty Point Hm Hf Hm TDH 1.2 0.5 0.3 24.8 Hm Hf Hm TDH 0.0 0.0 0.0 18.2 0.2 0.1 0.0 19.4 0.8 0.4 0.2 22.5 1.8 0.7 0.4 27.5 3.2 1.3 0.7 34.2 5.0 1.9 1.1 42.6 7.2 2.7 1.6 52.6 9.7 3.6 2.2 64.2 12.7 4.6 2.9 77.5 16.1 5.7 3.6 92.2 19.9 7.0 4.5 108.5 24.1 8.3 5.4 126.4 28.6 9.7 6.4 145.7 33.6 11.3 7.6 166.6 39.0 13.0 8.8 188.9 44.7 14.7 10.1 212.7 50.9 16.6 11.5 238.0 57.5 18.6 12.9 264.7 64.4 20.6 14.5 292.9 71.8 22.8 16.2 322.5 79.5 25.1 17.9 353.5 Willis Engineers 1984.015 15 June 2018 SS SS SS FTI 0 TOWN OF MOCKSVILLE JUNE 2018 UUMIS ENGINEERS DUTCHMAN'S CREEK WWTP SCALE PAGE WAS SYSTEM HEAD DEVELOPMENT 1 "=50' 16 Town of Mocksville Dutchman's Creek WWTP Narrative: A system head curve for the new scum pumps System Configuration Motor Top of Wetwell 663.50 ft MSL Wetwell Bottom 651.50 ft MSL Low Water Level 661.50 ft MSL Discharge 679.70 ft MSL Static Head 18.20 ft 40 35 30 w R 25 m x E c p 20 a 0 15 10 A 0 0 Scum System Head Development Pump Discharge 3" Motor 10 HP Speed 1750 RPM Efficiency 0.32 50 100 150 200 250 Flow (gpm) 50 45 40 35 0 m 30 2 m m CL 49 20 15 10 300 Willis Engineers 1984.015 17 June 2018 i i i i / / / / / / / / System Head 6.0 Vaughan V3FR — — — Efficiency 50 100 150 200 250 Flow (gpm) 50 45 40 35 0 m 30 2 m m CL 49 20 15 10 300 Willis Engineers 1984.015 17 June 2018 Town of Mocksville Dutchman's Creek WWTP Friction losses based on C = Diameter (in) Length (ft) Sum K Q (gpm) H 122 Q (gpm) H 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000 Scum System Head Development 115 4 6 308 268 7.67 5.14 106.9 121.5 136.9 153.1 170.2 188.1 206.8 Duty Point f Hm Hf Hm TDH 4.2 1.2 0.5 0.2 24.2 f Hm Hf Hm TDH 0.0 0.0 0.0 0.0 18.2 0.8 0.2 0.1 0.0 19.3 2.9 0.8 0.4 0.1 22.4 6.2 1.7 0.7 0.2 27.1 10.5 3.1 1.3 0.4 33.5 15.9 4.9 1.9 0.6 41.5 22.3 7.0 2.7 0.9 51.1 29.7 9.5 3.6 1.3 62.2 38.0 12.4 4.6 1.6 74.8 47.2 15.7 5.7 2.1 89.0 57.4 19.4 6.9 2.6 104.5 68.4 23.5 8.3 3.1 121.5 80.4 28.0 9.7 3.7 140.0 93.2 32.8 11.3 4.3 159.9 38.1 12.9 5.0 181.2 43.7 14.7 5.8 203.9 49.7 16.6 6.6 228.0 56.2 18.5 7.4 253.4 63.0 20.6 8.3 280.3 70.1 22.8 9.3 308.5 77.7 25.0 10.3 338.1 Willis Engineers 1984.015 18 June 2018 SS SS SS FTI 0 TOWN OF MOCKSVILLE JUNE 2018 UUMIS ENGINEERS DUTCHMAN'S CREEK WWTP SCALE PAGE SCUM SYSTEM HEAD DEVELOPMENT 1 "=50' 19 Town of Mocksville Dutchman's Creek WWTP Buoyancy Maximum Ground Water Elevation RAS Valve Vaults Buoyancy Calculation 665.70 ft M51- Depth SL Depth to Wet Well Invert 5.83 ft Wet Well Cross Section Area 46.7 ft 2 Bottom Slab Area 46.7 ft 2 Bottom Slab Thickness 0.5 ft Wet Well Volume 296 ft 3 Submerged Depth 6.3 ft Weight of Water 62.4 pcf Buoyancy 18,444 Ib Structure Weight Cross Sectional Area of Concrete Walls 10.7 ft 2 Weight of Walls 9664 lbs Weight of Base 3619 lbs Weight of Ballast 7238 lbs Unit Weight of Reinforced Concrete 155 pcf Unit Weight of Saturated Soil 47.6 pcf Approximate Weight of Structure 20,520 Ib Net Downforce 2,077 lb (ok) Willis Engineers 1984.015 20 June 2018 Town of Mocksville Dutchman's Creek WWTP RAS /WAS Wet Well Buoyancy Calculation Buoyancy Maximum Ground Water Elevation 665.70 ft M51- SLDepth Depthto Wet Well Invert 21.00 ft Wet Well Cross Section Area 156.00 ft 2 Bottom Slab Area 217.00 ft 2 Bottom Slab Thickness 1.50 ft Wet Well Volume 3602 ft 3 Submerged Depth 23 ft Weight of Water 62.4 pcf Buoyancy 224,734 Ib Structure Weight Cross Sectional Area of Concrete Walls 41 Weight of Walls 133455 Weight of Divider Wall 21700 Weight of Base 50453 lbs Weight of Soil 26989 Unit Weight of Reinforced Concrete 155 pcf Unit Weight of Saturated Soil 47.6 pcf Approximate Weight of Structure 232,597 Ib Net Downforce 7,863 lb (ok) Willis Engineers 1984.015 21 June 2018 Town of Mocksville Dutchman's Creek WWTP Scum Wet Well Buoyancy Calculation Buoyancy Maximum Ground Water Elevation 665.70 ft M51- SLDepth Depthto Wet Well Invert 12.00 ft Wet Well Cross Section Area 23.4 ft 2 Bottom Slab Area 28.2 ft 2 Bottom Slab Thickness 0.5 ft Wet Well Volume 294 ft 3 Submerged Depth 12.5 ft Weight of Water 62.4 pcf Buoyancy 18,372 Ib Structure Weight Cross Sectional Area of Concrete Walls 7 ft 2 Weight of Walls 13692 lbs Weight of Base 2185 lbs Weight of Soil 2876 pcf Unit Weight of Reinforced Concrete 155 pcf Unit Weight of Saturated Soil 47.6 pcf Approximate Weight of Structure 18,753 Ib Net Downforce MOW; (ok) Willis Engineers 1984.015 22 June 2018 Town of Mocksville WAS Valve Vaults Buoyancy Calculation Dutchman's Creek WWTP Buoyancy Maximum Ground Water Elevation 665.70 ft MSL Depth to Wet Well Invert 4.83 ft Wet Well Cross Section Area 17.1 ft 2 Bottom Slab Area 17.1 ft 2 Bottom Slab Thickness 0.5 ft Wet Well Volume 91 ft 3 Submerged Depth 5.3 ft Weight of Water 62.4 pcf Buoyancy 5,691 Ib Structure Weight Cross Sectional Area of Concrete Walls 6.3 ft 2 Weight of Walls 4679 lbs Weight of Base 1326 lbs Unit Weight of Reinforced Concrete 155 pcf Unit Weight of Saturated Soil 47.6 pcf Approximate Weight of Structure 6,005 Ib Net Downforce 314 Ib (ok) Willis Engineers 1984.015 23 June 2018 Town of Mocksville Flowmeter Vault Buoyancy Calculation Dutchman's Creek WWTP Buoyancy Maximum Ground Water Elevation 665.70 ft MSL Depth to Wet Well Invert 4.83 ft Wet Well Cross Section Area 14.7 ft 2 Bottom Slab Area 14.7 ft 2 Bottom Slab Thickness 0.5 ft Wet Well Volume 78 ft 3 Submerged Depth 5.3 ft Weight of Water 62.4 pcf Buoyancy 4,887 Ib Structure Weight Cross Sectional Area of Concrete Walls 5.7 ft 2 Weight of Walls 4263 lbs Weight of Base 1139 lbs Unit Weight of Reinforced Concrete 155 pcf Unit Weight of Saturated Soil 47.6 pcf Approximate Weight of Structure 5,402 Ib Net Downforce 515 Ib (ok) Willis Engineers 1984.015 24 June 2018 Town of Mocksville Dutchman's Creek WWTP Splitter Box Buoyancy Calculation Buoyancy 34.7 Maximum Ground Water Elevation 665.70 ft MSL Depth to Wet Well Invert 5.00 ft Wet Well Cross Section Area 76.7 ft 2 Bottom Slab Area 76.7 ft 2 Bottom Slab Thickness 1.0 ft Wet Well Volume 460 ft 3 Submerged Depth 6.0 ft Weight of Water 62.4 pcf Buoyancy 28,705 Ib Structure Weight Cross Sectional Area of Concrete Walls 34.7 Weight of Walls 26869 Weight of Base 11884 lbs Unit Weight of Reinforced Concrete 155 pcf Unit Weight of Saturated Soil 47.6 pcf Approximate Weight of Structure 38,753 Ib Net Downforce 10,048 Ib (ok) Willis Engineers 1984.015 25 June 2018 Town of Mocksville Dutchman's Creek WWTP Renovation Flow/ Kinetic Parameters: Average Plant Flow 0.45 MGD Design Plant Flow 0.98 MGD Yield 0.5 lbs VSS/Ibs BOD Influent BOD 250 mg/I Effluent BOD 5 mg/I Influent TSS 250 mg/I Effluent TSS 30 mg/I Volatile Fraction of TSS 75% Sludge Solids (without solids thickening) 0.5% to 1.0% Proposed Sludge Solids (thickened) 2.0% to 4.0% Specific Gravity 1.005 Puma Parameters: Sludge Thickener Requirements Waste Pump Flow Rate (to thickeners) 100 to 125 gpm. Thickener Run Time at Current Flow 4 hours / day Thickener Run Time at Design Flow 6 hours / day After the sludge is thickened, it will need to be pumped to the aerobic digesters: Static Elevation: 12 feet Pipe Length: 122 feet Diameter: 6 inches** Fittings: 90 ° Bends 4 Plug Valves 4 Tees (side outlet) 2 ** Pipe diameter can be reduced if necessary Willis Engineers 1984.015 26 June 2018 Town of Mocksville Sludge Thickener Requirements Dutchman's Creek WWTP Renovation Solids Production, Average Flow: From TSS = (1 — 0.75) * (250 mg — 30 s I mg l) * 8.34 * 0.45 MGD = 207 lbs Y C mg 5mg) lbs VSS From BOD = 250 l — l * 8.34 * 0.45 MGD * 0.5 lbs BOD = 460 lbs/day lbs lbs lbs Total Solids = 207 da + 460 da da = 667 Y Y Y Solids Production, Design Flow: mg mg lbs From TSS = (1 — 0.75) * (250-30—) l — * 8.34 * 0.98 MGD = 408 day mg 5mg lbs VSS From BOD = (250 l — l ) * 8.34 * 0.78 MGD * 0.5 lbs BOD = 1001 lbs/day lbs lbs lbs Total Solids = 359 da + 797 da da = 1409 Y Y Y Daily Volume of Sludge to Thickeners, Average Flow: 667las Volume = y lbs = 15,915 gpd 1.005 x (0.5% ) x 8.34 gal Daily Volume of Sludge to Thickeners, Design Flow: 1409las Volume = y lbs = 33,620gpd 1.005 x (0.5%) x 8.349x1 Willis Engineers 1984.015 27 June 2018 ELECTRICAL LOAD TABULATION FEEDER DESCRIPTION KVA USE NET MDP -1 TREATMENT CELL 2 93.0 2.0 100% 2.0 350A 4 @ 7.5HP 36.0 100% 36.0 AERATORS 2 @ 25HP 54.0 100% 54.0 100% PANEL SPB2 MISC 2.0 100% 2.0 22.0 PANEL CLB2 MISC 2.0 100% 2.0 2HP BLOWERS 2 @ 5HP 12.0 100% 12.0 MDP -3 DIGESTER AREA 300A PANEL PD MISC 5.4 50% 2.7 DRUM 11.1 100% 11.1 HVAC 10.0 100% 10.0 HEADWORKS 9.0 67% 6.0 BLOWERS 3 ® 20HP 63.0 67% 42.0 MDP -4 CLARIFIER AREA 300A PANEL PC MISC 93.0 2.0 100% 2.0 RECYCLE PUMPS 4 @ 7.5HP 36.0 100% 36.0 WASTE PUMPS 3 © 3HP 10.0 100% 10.0 SLUDGE PUMPS 2 @ 10HP 22.0 100% 22.0 CLARIFIERS 2 © 2HP 6.0 100% 6.0 MDP -5 INFLUENT PUMP STATION 400A INFLUENT PUMPS 3 © 30HP 93.0 100% 93.0 MDP -6 TREATMENT CELL 3 400A AERATORS 2 @ 25HP 54.0 100% 54.0 PANEL SPB3 MISC 2.0 100% 2.0 BLOWERS 2 © 5HP 12.0 100% 12.0 MDP -13 LAB BUILDING 200A PANEL L1 MDP -14 TREATMENT CELL 1 250A AERATORS MISC 5.0 100% 5.0 2 © 25HP 54.0 100% 54.0 440.5 KVA © .85PF = 374.4 KW. THE EXISTING GENERATOR IS RATED 400 KW, OR 500 KVA © .8PF. 28