7 Method of Control Typical Grease Interceptor Design
8 Honolulu Wastewater System Number of Treatment Plants Number of Pump Stations Total Design Flow (mgd) Collection System - approximately 2,000 miles of sewer lines Honolulu population is about 800,000.
9 Compliance Background 1982 Honolulu’s Pretreatment Program Approved by EPA 1990 EPA issues Findings of Violations to Honolulu (related to SSO’s) 1995 Honolulu enters into Consent Agreement with EPA 1999 GI retrofit program begins; 90 grease related SSO’s = 36% of total annual SSO’s % of facilities retrofitted; 46 grease related SSO’s = 23% of total annual SSO’s.
10 Collection System Maintenance & Historical Data
11 Collection System Maintenance Repair collection system conditions which promote grease blockages (e.g. line sag, surcharge conditions, pipe cracks/breaks, root intrusion). Modify collection system standards to accommodate grease (e.g. seamless pipe, increased slope, larger pipe). Conduct effective preventive maintenance program (i.e. identify and target “hot spots”). Report chronic FOG problem areas or dischargers to the Pretreatment Program for enforcement. Maintain detailed and accurate records of system condition. Infrastructure Efforts to control FOG
12 Collection System Historical Data LOCATION % of GIs upgraded % of records indicating heavy grease in line KALAKAUA 0%12% 67%100% 67% KAPIOLANI 4% 9% 92%82%100% AUAHI 0% 5%11% 100% ALA MOANA 0%6% 100% Areas with Low Percentage of Retrofitted GIs Approximately 20% of businesses requiring a GI have been retrofitted.
13 Collection System Historical Data LOCATION % of GIs upgraded % of records indicating heavy grease in line BERETANIA 0% 12%21% 96%100%23%22% KAM HWY 0%10%15%20% 75%50% 0% KALAKAUA 0%5%10%25% 100% 75%0% KALAKAUA 0%8%33% 84%80%35%14% Areas with Higher Percentage of Retrofitted GIs Approximately 20% of businesses requiring a GI have been retrofitted.
14 Collection System Historical Data YearMiles of Pipes Cleaned Number of Wastewater Spills Number of Grease Related Spills * Grease Spills as a Percentage of Total Spills % % % % 1999 ** % % % % * Grease was primary cause of spill ** Began GI retrofits in June 1999 (20% Complete) Pipe Cleaning and Spill Records:
15 Collection System Historical Data Year Flow (mgd) Influent O&G (mg/l) Grease Spills * Reduction %10%45%48% Sand Island WWTP Data: * O&G analytical method changed from to 1664A (freon to hexane) in November 1998, as well as, new NPDES permit required increased monitoring frequency from 1/week to 3/week.
16 Pretreatment Program
17 Pretreatment Program Many Fats, Oil and Grease (FOG) Sources are Not Connected to a GI (Pre-rinse garbage disposals). Existing Grease Interceptors (GI) are “Inadequate”. How do you determine what is adequate? Research Findings:
18 Pretreatment Program Consider…Stokes’ Law: Vr = g/18ν [S.G.w – S.G.o] x D² Where: Vr – rising velocity of the oil particle (cm/sec) g – gravity constant (980 cm/sec²) ν – viscosity of water in poises (0.01) S.G.w – specific gravity or density of water (gm/cm³) S.G.o – specific gravity or density of oil (gm/cm³) D - diameter of the oil droplet (cm)
19 Pretreatment Program Factors Affecting FOG Separation: 1. Temperature – the less viscous the fluid (higher temp.), the faster the particle rise rate. However, too high temp. promotes emulsification. 2.Specific Gravity - The greater the differential specific gravity or density between the fluid and the particle, the faster the rise rate. 3.Diameter – The larger the particle diameter the faster the particle rise rate.
20 Pretreatment Program Oil Globule Rise Times for 3 68 F: Diameter [microns] Rise Time (S.G.=0.9) [hr:min:sec] 3000:00: :01:27 600:06:36 400:14:24 200:58:08 10 (colloidal)3:52: :35:49 Table info from American Petroleum Institute Publication 421. FOG S.G. range =
21 Pretreatment Program YEAH BABY, YEAH!! Grease Interceptors must be sized to promote the adequate separation of FOG from wastewater. An important factor to consider is……….. Retention Time Does Size Matter??
25 Pretreatment Program Comparison of Grease Interceptor Sizing Criteria UPC Appendix H 1999 Honolulu Criteria (Denver Based)2001 Honolulu Criteria Type of Facility Calculated Size Tank Requirement Calculated Size Tank Requirement Calculated Size Tank Requirement Chinese Restaurant 6,0002 x 3,0001,1251, ,000 Seafood Restaurant 6,0002 x 3,0002,0883,0001,0801,500 Fine Dining 16,5003 x 5,000 +3,2754,0001,3901,500 Hotel with Kitchen and Restaurant 3,5004,0001,6882,0001,0501,500 Dinner Theatre (Luau) 7,5002 x 4,0002,5003, ,000 Large Restaurant 10,3202 x 5,000 +3,2254,0002,5203,000 Medium Restaurant 2,1003,0001,5312,0001,2081,500 Small Restaurant ,
26 Pretreatment Program HONOLULU SIZED GREASE INTERCEPTOR SAMPLING RESULTS Number of GIs sampled-45 Number of samples taken-90 Average Oil & Grease Effluent Concentration (Avg)-79 mg/l pH - (min) 5 (avg) 5.8 (max) 7 Temp. (degrees F) - (min) 69º (avg) 86.6º (max) 105º (Melting Point of Tallow (i.e. animal fat) degees F)
27 Pretreatment Program GI Maintenance Requirements 25% RULE Storage factor used to determine GI maintenance frequency consisting of surface FOG material and settled solids. PUMP-IN-FULL –Insure all solids are removed. –Inspect the GI for corrosion damage or cracks. –Enables “cradle-to-grave” tracking of FOG waste.
28 FOG Control Success Factors
29 FOG Control Success Factors Consistent Facility Compliance Evaluations Persistent/Consistent Enforcement Actions Plan Reviews to verify Compliance with GI Program Database Tracking and Follow-up Program Implementation Strategy Economic Considerations Public Outreach and Education
30 FOG Control Success Factors Program Implementation Strategy! 1. Understand the Political Environment – Votes. 2. Understand the Media – Stay 2 steps ahead. Create a “No Story” situation. 3. Involve the Industry – Raise awareness by meeting with Stakeholders (Property Owners, Restaurant Owners, Area Organizations/ Committees, Trade and Business Associations, City and Elected Officials). 4. Think “Money” - Businesses focus is on $. Find a way to merge environment and regulations. Build partnerships with the “Big Dogs”.
31 FOG Control Success Factors Project coordination & funding by property owners: –Property owners and tenants equally liable under most Ordinances. –Owners finance improvements and renegotiate tenant leases. –Tenants pay only their fair share while they are there. Shared Grease Interceptors Mixed Waste (kitchen/domestic) Grease Interceptors. [Currently 2 operating in Hawaii with more proposed] Grant easements where space is limited. ADDITIVES - Biologicals Only…No Enzymes or Surfactants. Economic Considerations:
32 FOG Control Success Factors Public Outreach and Education Public Info Meetings, Community/Industry Events Brochures, Bus Posters Educational Videos/Public Service Anouncements (Show Video)
33 Contact Information James Baginski, P.E. President James Baginski Enterprises 731 Kokomo Place Honolulu, Hawaii Tel: (808)