For: New England Interstate Water Pollution Control CommissionMay 13, 2009

Town of Cary FOG Town of Cary FOG Hi hli htHi hli htprogram: Highlightsprogram: Highlights

Leon HoltLeon Holt(retired)(retired) Pretreatment MangerPretreatment Manger

Town of CaryTown of CaryTown of Cary Town of Cary http://www.townofcary.org/grease/fogordinance.pdfhttp://www.townofcary.org/grease/fogordinance.pdf

History: initiated 1997; Finalized 1998 as History: initiated 1997; Finalized 1998 as t f S U O dit f S U O dicomponent of Sewer Use Ordinancecomponent of Sewer Use Ordinance

Ordinance objectives: be short conciseOrdinance objectives: be short conciseOrdinance objectives: be short, concise, Ordinance objectives: be short, concise, and adopt by reference, other components and adopt by reference, other components of effective FOG management programof effective FOG management programof effective FOG management programof effective FOG management programLegal Authority 1 Legal Authority 1 –– NC issued NPDES NC issued NPDES permit Pretreatment Programpermit Pretreatment Programpermit, Pretreatment Programpermit, Pretreatment ProgramLegal Authority 2 Legal Authority 2 –– NC sanitary sewer NC sanitary sewer

ll ti t ittill ti t itticollection system permitting program; collection system permitting program; component of NC Clean Water Act of 1999component of NC Clean Water Act of 1999

HighlightsHighlightsHighlightsHighlightsApplicability Applicability –– FSE use of ware requiring washing for reuse qualifies FSE use of ware requiring washing for reuse qualifies FOG managementFOG managementFOG management. FOG management.

GI sizing: based on calculated hydraulic loading, from drainage GI sizing: based on calculated hydraulic loading, from drainage fixtures fixtures

Exceptions considered: existing vs new, no “grandfathering”. BAT, Exceptions considered: existing vs new, no “grandfathering”. BAT, BPJ, BPT alternatives developed. Example: Hot Water prerinse, GI BPJ, BPT alternatives developed. Example: Hot Water prerinse, GI decanting de minimus FOG loading menu impact collection systemdecanting de minimus FOG loading menu impact collection systemdecanting, de minimus FOG loading, menu impact, collection system decanting, de minimus FOG loading, menu impact, collection system characteristics; all requiring Town review/approvalcharacteristics; all requiring Town review/approval

Local limits: Chronic numeric limit dropped, BMP enforced. Acute Local limits: Chronic numeric limit dropped, BMP enforced. Acute pp ,pp ,limit, as “action level” adopted if SSO, blockage, reduced sewer limit, as “action level” adopted if SSO, blockage, reduced sewer conveyance capacity downstream of FSE is realized.conveyance capacity downstream of FSE is realized.

Highlights continuedHighlights continuedHighlights continuedHighlights continued

Enforcement response planEnforcement response plan –– TieredTieredEnforcement response plan Enforcement response plan TieredTieredGrease interceptor design Grease interceptor design –– based on based on computation flow dynamic modelscomputation flow dynamic modelscomputation flow dynamic models computation flow dynamic models investigated by NC State Univ. Civil investigated by NC State Univ. Civil Engineering Dept. Engineering Dept. g g pg g pDecanting, or onDecanting, or on--site GI treatment: site GI treatment: conditional, applies to tested/approved conditional, applies to tested/approved pp pppp pptechnologies. Local limits applytechnologies. Local limits applyProgram Recovery Fee, $120/annuallyProgram Recovery Fee, $120/annuallyg y yg y y

Hightlights continuedHightlights continuedHightlights continuedHightlights continuedNo permit issued to FSE: instead, a mutually No permit issued to FSE: instead, a mutually p yp ysigned FOG Program Acknowledgement signed FOG Program Acknowledgement Certificate is issued. Certificate must be Certificate is issued. Certificate must be displayed at FSE in plain sight of kitchen staff. displayed at FSE in plain sight of kitchen staff. p y p gp y p gPumping frequency: every 60 daysPumping frequency: every 60 days25% “rule” always applies; can override pump 25% “rule” always applies; can override pump f b if d df b if d dfrequency above if exceeded.frequency above if exceeded.Waste food grinders, if used, must be Waste food grinders, if used, must be intercepted in GI of Town approved sizeintercepted in GI of Town approved sizete cepted G o o app o ed s ete cepted G o o app o ed s eFSE notified, in writing, of GI selfFSE notified, in writing, of GI self--cleaning rules cleaning rules as administered by State of NC.as administered by State of NC.http://www townofcary org/grease/fogordinance pdfhttp://www townofcary org/grease/fogordinance pdfhttp://www.townofcary.org/grease/fogordinance.pdfhttp://www.townofcary.org/grease/fogordinance.pdf

Highlights continuedHighlights continuedg gg gPlan review and site/construction reviews: all FSE’s. Fee structure Plan review and site/construction reviews: all FSE’s. Fee structure in place for repeat inspections (site/construction)in place for repeat inspections (site/construction)p p p ( )p p p ( )

Storm water inflow diversion to GI from qualified sites: covered Storm water inflow diversion to GI from qualified sites: covered compactors at grocery stores, apartment complexes, institutional compactors at grocery stores, apartment complexes, institutional FSEsFSEsFSEsFSEs

Pumping records required to be kept at FSE sitePumping records required to be kept at FSE site

Responsible party for GI maintenance: Property owner; tenant/lease Responsible party for GI maintenance: Property owner; tenant/lease arrangements possiblearrangements possible

Educational program directed to Police Dept., re: illegal dumping Educational program directed to Police Dept., re: illegal dumping detection and interventiondetection and intervention

Highlights continuedHighlights continuedHighlights continuedHighlights continuedPumper seminars, FSE workshops Pumper seminars, FSE workshops p , pp , pBiological additives conditionally acceptable, Biological additives conditionally acceptable, pending review and approval of Town. Not pending review and approval of Town. Not

b i f i l T db i f i l T dsubstitute for pumping, unless Town approved.substitute for pumping, unless Town approved.Interaction with State, County, NC State Interaction with State, County, NC State University Civil Engineering Dept NCUniversity Civil Engineering Dept NCUniversity Civil Engineering Dept., NC University Civil Engineering Dept., NC Pretreatment ConsortiumPretreatment ConsortiumOil/water separator program for hydraulic Oil/water separator program for hydraulic O / ate sepa ato p og a o yd au cO / ate sepa ato p og a o yd au celevators, auto shops, equipment elevators, auto shops, equipment servicing/cleaning establishments.servicing/cleaning establishments.

Some Program ElementsSome Program ElementsSome Program ElementsSome Program Elements

GI sizing: Excel spreadsheetGI sizing: Excel spreadsheet –– based onbased onGI sizing: Excel spreadsheet GI sizing: Excel spreadsheet based on based on 24 minute HRT (confirmed as adequate by 24 minute HRT (confirmed as adequate by NC State) gravity hydraulic flow deliveryNC State) gravity hydraulic flow deliveryNC State), gravity hydraulic flow delivery NC State), gravity hydraulic flow delivery to GI. (demonstrate here)to GI. (demonstrate here)Local limits for decanting qualifying GIs GILocal limits for decanting qualifying GIs GILocal limits for decanting qualifying GIs GI Local limits for decanting qualifying GIs GI design requirementsdesign requirements

Excel GI sizing spreadsheetExcel GI sizing spreadsheetExcel GI sizing spreadsheetExcel GI sizing spreadsheetThe Town of Cary Grease Interceptor Sizing Spreadsheet was developed The Town of Cary Grease Interceptor Sizing Spreadsheet was developed

i d t i i t t b d th f ti f ifii d t i i t t b d th f ti f ifiin order to size a grease interceptor based on the function of specific in order to size a grease interceptor based on the function of specific kitchen sink fixtures and their peak hydraulic loading based on kitchen sink fixtures and their peak hydraulic loading based on intended use of the fixtures and a desired hydraulic residence time. intended use of the fixtures and a desired hydraulic residence time. Sink fixtures and cooking equipment that are filled and are drained areSink fixtures and cooking equipment that are filled and are drained areSink fixtures and cooking equipment that are filled and are drained are Sink fixtures and cooking equipment that are filled and are drained are calculated using the Manning Formula which takes into account sink calculated using the Manning Formula which takes into account sink pipe drain size, maximum flow depth in the drain pipe, material pipe drain size, maximum flow depth in the drain pipe, material types/roughness coefficients and pipe slope to determine thetypes/roughness coefficients and pipe slope to determine thetypes/roughness coefficients, and pipe slope to determine the types/roughness coefficients, and pipe slope to determine the maximum flow rate from the fixture. Sink fixtures not typically filled maximum flow rate from the fixture. Sink fixtures not typically filled and relying on running water are calculated based on the and relying on running water are calculated based on the manufacturer's specification for the delivery flow rate of the fixture manufacturer's specification for the delivery flow rate of the fixture p yp yfaucet based on the average water supply pressure. Additional faucet based on the average water supply pressure. Additional information can be obtained by locating comments throughout the information can be obtained by locating comments throughout the equipment schedule and data entry sheets. equipment schedule and data entry sheets.

Hyperlink to Excel sizing SpreadsheetHyperlink to Excel sizing Spreadsheet

OnOn--site Pumper Decantingsite Pumper DecantingOnOn site Pumper Decantingsite Pumper Decanting

Technology based local limitsTechnology based local limitsTechnology based local limitsTechnology based local limitsPolicy considerations: Yes or No?Policy considerations: Yes or No?B i f d i i ?B i f d i i ?Basis for decision?Basis for decision?

Example: 30 min Settleable Solids Tests

15 sites

225 ml/L

10.5 ml/L 3.0 ml/L

New Objective: Distributed Flow New Objective: Distributed Flow Inlet and Outlet Tees = Distributed FlowInlet and Outlet Tees = Distributed FlowInlet and Outlet Tees Distributed Flow Inlet and Outlet Tees Distributed Flow

across tank length (2:1 l/w ratio)across tank length (2:1 l/w ratio)

Inlet Tee Outlet Tee

Lined concrete GI’sLined concrete GI’sLined concrete GI sLined concrete GI s

prevent H2S corrosion damageprevent H2S corrosion damageprevent H2S corrosion damageprevent H2S corrosion damage

electronic inspection and record electronic inspection and record managementmanagement