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Types, Sizing, Application and Maintenance A Brief Overview Presented by Max Weiss, Consultant Jay R. Smith Mfg. Co., Inc. Jay R. Smith Mfg. Co., Inc.

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Presentation on theme: "Types, Sizing, Application and Maintenance A Brief Overview Presented by Max Weiss, Consultant Jay R. Smith Mfg. Co., Inc. Jay R. Smith Mfg. Co., Inc."— Presentation transcript:

1 Types, Sizing, Application and Maintenance A Brief Overview Presented by Max Weiss, Consultant Jay R. Smith Mfg. Co., Inc. Jay R. Smith Mfg. Co., Inc.

2 Nomenclature: Traps vs. Interceptors 1 Interceptor Subtypes 2-6 Hydromechanical Grease Interceptors (GIs) Grease Recovery Devices (GRDs) Fats, Oils and Grease (FOG) Disposal Systems Gravity Grease Interceptors Sizing 7-11 Hydromechanical GIs – based on pipe size Gravity GIs – based on pipe size Hydromechanical GIs – based on fixture capacity Gravity GIs – based on fixture capacity Application 12 Maintenance Pros/Cons by Type Conclusion 24

3 Nomenclature clarification Recent changes in codes and standards to clarify mixed terms Trap has been eliminated in ASME Standards, UPC, CSA and (pending) IPC Interceptor is deemed to be a more inclusive term Interceptor allows for a more precise distinction between devices First official adoption was by IAPMO during its comprehensive rewrite of Chapter Ten (10) of the Uniform Plumbing Code. 1

4 Hydromechanical Grease Interceptors (GIs) Grease Recovery Devices (GRDs) Fats, Oils and Grease (FOG) Disposal Systems Gravity Grease Interceptors 2

5 Definition Hydromechanical Grease Interceptor [Plumbing Drainage Institute] 3

6 Definition Grease Removal Device [Plumbing Drainage Institute] 4

7 Definition FOG Disposal System [Plumbing Drainage Institute] 5

8 Definition Gravity Interceptor [Plumbing Drainage Institute] 6

9 UPC, Chapter 10, Appendix H Limitations Drainage Fixture Units [DFU] Misconception Maximum Flow Sizing Grease Interceptor Sizing Truths 7

10 Pipe DiameterSlope*GPM**Nominal Interceptor Rating gpm gpm gpm gpm gpm gpm gpm gpm gpm gpm gpm gpm * Inches drop per foot of run. **Based on Mannings formula with friction factor N=.012 as published by Cast Iron Soil Pipe Institute (CISPI) Or, actual fixture volume plus hydrant capacity, divided by drain period whichever is less. 8

11 Pipe DiameterSlope*GPM**Nominal Interceptor Volume*** gal , , , , , , , , , ,000 * Inches drop per foot of run. **Based on Mannings formula with friction factor N=.012 as published by Cast Iron Soil Pipe Institute (CISPI) ***Based on 30 min. retention (Metcalf & Eddy) rounded to nearest volume of 250 gal. increments. Or, actual fixture volume plus hydrant capacity, divided by drain period X 30 whichever is less. 9

12 Calculation of fixture capacity: [Length] X [Width] X [Depth] / [231] = Gallons X [.75 fill factor] / [Drain Period (1 or 2)] Add hydrant capacity (gpm supply); Add dishwasher, water wash hood at manufacturer ratings. EXAMPLE: Fixture Compartment Size, in. Compartments Load,galRecommended Interceptor Size, One-Minute Drain Two-Minute Drain 24x24x The selection listed is based on application of the sizing formula above. 10

13 Multiply the result of either "Fixture Capacity" or "Pipe Size" (above) by 30 to reflect required retention time. EXAMPLE 35 gpm X 30 = 1,050 gal. capacity. This sizing method is the "Uniform Interceptor Sizing – for obvious reasons. All parameters are uniformly applied to the computation of GPM from any given facility to any given interceptor. 11

14 Why is an interceptor required? Pretreatment as the prime consideration Administrative convenience versus concern for water quality Versatility of installation, proximity to FOG source, decreased maintenance frequency 12

15 Hydromechanical GIs Pros Located near the FOG source Usually small compared to gravity units Can be cleaned with conventional dip and bucket or small vacuum units Cons More convenient to ignore than to clean Will continue to flow water even after they no longer function as an interceptor Rarely have third party maintenance verification 13

16 Grease Removal Devices Pros Located near the FOG source Automatically remove FOG for proper disposal Less maintenance required Cons More expensive initially than hydromechanical GIs Require solids separation preceding the waste stream Have moving parts and are prone to mechanical problems 14

17 FOG Disposal Systems Pros Require less maintenance than GRDs – some requiring only annual service Can be quite small relative to the size flow capable of being treated Have the most rigorous performance testing and usually provide the cleanest effluent Remove solids with the use of a solids interceptor Cons More expensive than hydromechanical GIs and most GRDs Require attention to solids interceptors – neglect can affect performance of some units Frequently foreign to local jurisdictions 15

18 Gravity Interceptors Pros More recognized and usually easier to get approved by local authorities Require little or no attention from the facility operator Compatible with third party maintenance Cons Significantly more difficult and expensive to install The most frequently improperly sized interceptors The least efficient in terms of FOG separation Prone to hydrogen sulfide generation and accelerated corrosion Falsely believed to be capable of FOG storage exceeding 30 days Expensive to service at proper frequency and thoroughness 16

19 17 FOG in Lift Station

20 18 Corrosion Interior Concrete Interceptor

21 19 Other Lines in Lift Station

22 20 Combined Sewer Clogged with Grease

23 21 Grease in PVC Pipe

24 22 Channel in Grease Layer

25 23 Bag Type Interceptor

26 Rarely is the best interceptor for the job selected. Even more rarely is the selected interceptor sized correctly. Even rarer still is the interceptor that is installed correctly. Nonexistent is the interceptor that is the right interceptor for the job, sized properly, installed correctly AND operated and maintained as the manufacturer intended with the intent of producing the highest quality effluent possible. 24

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