grease interceptors

Document Sample
grease interceptors Powered By Docstoc
					Types, Sizing, Application and
        Maintenance

      A Brief Overview




             Presented by Max Weiss, Consultant
                   Jay R. Smith Mfg. Co., Inc.
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                                                13-23
         Pros/Cons by Type
Conclusion                                                   24
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
Hydromechanical Grease Interceptors (GIs)


Grease Recovery Devices (GRDs)


Fats, Oils and Grease (FOG) Disposal Systems


Gravity Grease Interceptors




                                               2
Definition




             Hydromechanical Grease Interceptor [Plumbing Drainage Institute]


                                                                        3
Definition




             Grease Removal Device [Plumbing Drainage Institute]


                                                            4
Definition




             FOG Disposal System [Plumbing Drainage Institute]


                                                          5
Definition




             Gravity Interceptor [Plumbing Drainage Institute]


                                                          6
UPC, Chapter 10, Appendix H Limitations



Drainage Fixture Units [DFU] Misconception



Maximum Flow Sizing



Grease Interceptor Sizing Truths




                                             7
Pipe Diameter               Slope*           GPM** Nominal Interceptor Rating
2.0                         .120             13.75            15gpm
                            .240             19.44            20gpm
3.0                         .120             41.49            50gpm
                            .240             58.67            75gpm
4.0                         .120             88.93            100gpm
                            .240             125.77           125gpm
5.0                         .120             162.46           175gpm
                            .240             229.75           250gpm
6.0                         .120             265.50           275gpm
                            .240             375.47           400gpm
8.0                         .120             575.81           600gpm
                            .240             814.32           825gpm
* 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
Pipe Diameter                Slope*              GPM** Nominal Interceptor Volume***
2.0                          .120                13.75        500 gal.
                             .240                19.44        750
3.0                          .120                41.49        1,250
                             .240                58.67        1,800
4.0                          .120                88.93        2,750
                             .240                125.77       4,000
5.0                          .120                162.46       5,000
                             .240                229.75       7,000
6.0                          .120                265.50       8,000
                             .240                375.47       11,500
8.0                          .120                575.81       18,000
                             .240                814.32       25,000
* 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
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,   Compartments      Load,gal   Recommended Interceptor Size,
        in.

                                                         One-Minute    Two-Minute
                                                            Drain         Drain
   24x24x12                      2             44.9           50           25



The selection listed is based on application of the sizing formula above.



                                                                                         10
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
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
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
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
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
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
FOG in Lift Station
                      17
Corrosion Interior Concrete Interceptor

                                          18
Other Lines in Lift Station

                              19
Combined Sewer Clogged with Grease

                                     20
Grease in PVC Pipe
                     21
Channel in Grease Layer
                          22
Bag Type Interceptor
                       23
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

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:81
posted:10/4/2012
language:English
pages:27