Collaborative Study on Fats, Oil and Greases in Drain and Sewer Systems

Water Services National Training Group

Outcome Awareness Day

24th March 2009

Collaborative Study on Fats, Oil and Greases in Drain and Sewer Systems

Midleton FOG Project

Sam Crowley B.E. (Civil)Project Engineer, Response Engineering

M. Eng. Sc. StudentCivil & Env. Eng. UCC (Prof. G. Kiely, Supervisor)

Midleton FOG Project

Midleton, Co. Cork

History of FOG related problems.

Population: 9,019

There are 63 FOG generators in Midleton.

€68,372 spent in 2005 including cleaning of pumping

stations €39,687 of this for FOG related work.

Approximately 58% of total spent on drain cleaning.

MethodologyFOG Hotspots1. Identified2. Analysed3. Evaluated (Baseline)

CCTV surveys Inspection of existing Grease Removal Unit (GRU) GRU maintenance procedures investigated Staff interviews

Blockage history Kitchen practices Awareness

Site survey

Methodology (Continued)

FOG Hotspots4. Potential solutions selected and installed.5. Minimum of 6 month trial6. Difficulties7. Information Evening

Midleton FOG Project

System Types Tested: No. of Installations

Passive Interceptor (Untreated) 3

Passive Interceptor(with Biological Treatment) 3

Active/Mechanical Interceptor 5

Biological Treatment System 2

Site Type: Quantity:Fast Food Takeaway s 2Restaurants 2Laundrettes 1Butcher Shops 1Convenience Shops 3Fish Retailer & Manufacturers 1Hotels 1Bar/ Restaurants 1Chinese Restaurants 1Hospitals 1Supermarkets 1Pumping Stations 4Sewer Hotspots 2Wastewater Treatment Plants 1Café Bakeries 1Sandwich Shops 1

Midleton FOG Project

Methodology (Continued)

Trial Period1. Monitoring2. Observing3. Recording4. Maintaining5. Sampling Programme6. Final CCTV Survey

Active/Automatic vs. Passive Systems

Automatic/Active vs. Passive Systems

Active PassiveMoving Parts, power, water Volume Compact Large

Location At Source At or away from source

Maintenance Interval

1 Day 2 Weeks (depending on storage and load)

Waste FOG Clean Dirty, Contaminated

Waste Food Not decaying Decaying

Biological Dosing Occasionally

Portable Interceptor

Similar to passive interceptor

Maintained by contractor

Unit swapped with clean unit every two weeks.

Full unit is removed from site and cleaned at contractors premises

Removes need for maintaining unit within kitchen – hygiene and odour issues

Aluline - BioBlock

Biological treatment for use in sewer network

Installed in manhole at FOG Hotspot 1

Replaced each month

Build up still occurred

Blockage rate significantly decreased

Cleveland Biotech - Bactaerator

Biological treatment for use in pumping stations

Water is aerated continuously

Bacteria and nutrient solutions are dosed into water at times of low flow

Build up of FOG on walls decreased

Cleaning interval increased

Cleveland Biotech - Bactaerator

1 week since previous cleaning

15 weeks since previous cleaning

Root Cutting

Root intrusions shown in initial survey (24/07/06)

Re-growth of roots 8 months after cutting (31/03/08)

System Performance SummarySite Customers/

Meals per DayExisting Grease

Management SystemGrease Management System

InstalledNo. of

samples analysed:

Lowest Result (mg/l):

Highest Result (mg/l):

Average Result (mg/l):

% < 50 mg/l:

% < 100 mg/l:

Fast Food Takeaway 1

60 (Weekday); 200 (Weekend)

200 litre JFC passive interceptor

None 1 120 120 120 0 0

Restaurant 1Up to 50 at weekend

NoneAluline AG2 300 litre passive

interceptor with treatment.3 191 8896 4275.7 0 0

Butcher Shop 1 150 - 500 None2no. 21 litre PVC Fabrications

Passive Interceptors2 1148 1498 1323 0 0

Fish Retailer & Manufacturer 1

70 approx. None3no. 50 litre Miskin mobile

passive interceptors 

1) Shop 1 147 147 147 0 0 2) Kitchen 6 73 1977 729.3 0 16.7 3) Oven 5 <1 245 94.6 60 60

Hotel 1 up to 1200 220 litre grease trap3270 litre Kent Stainless passive interceptor with

treatment8 15 799 175.4 25 50

Convenience Shop 2

100 to 200 from deli

Domestic model JFC underground passive

interceptor

JFC GT02 200 litre underground passive

interceptor downstream of existing trap

8 38 1056 327 12.5 37.5

Fast Food Takeaway 2

400 to 600 None Fatstrippa interceptor 6 20 525 212 16.7 33.3

Hospital 1 Up to 290400 litre Blucher passive

interceptorService Package with biological treatment

9 34 813 245.2 11.1 44.4

Café/Bakery 1 Not known NoneFS05 Fatstrippa Active

Interceptor1 331 331 331 0 0

Restaurant 2 Not known NoneFS10 Fatstrippa Active

Interceptor2 29 205 117 50 50

Sandwich Shop 1 Not knownGreaseShield Mechanical

InterceptorNone 4 129 982 632.3 0 0

System Performance SummarySite Existing Grease

Management SystemGrease Management System

InstalledAverage Result (mg/l):

% < 50 mg/l:

% < 100 mg/l:

Fast Food Takeaway 1200 litre JFC passive

interceptorNone 120 0 0

Restaurant 1 NoneAluline AG2 300 litre passive

interceptor with treatment.4275.7 0 0

Butcher Shop 1 None2no. 21 litre PVC Fabrications

Passive Interceptors1323 0 0

Fish Retailer & Manufacturer 1

None3no. 50 litre Miskin mobile passive

interceptors  

1) Shop 147 0 0 2) Kitchen 729.3 0 16.7 3) Oven 94.6 60 60

Hotel 1 220 litre grease trap3270 litre Kent Stainless passive

interceptor with treatment175.4 25 50

Convenience Shop 2Domestic model JFC underground passive

Interceptor

JFC GT02 200 litre underground passive interceptor downstream of

existing trap327 12.5 37.5

Fast Food Takeaway 2 None Fatstrippa interceptor 212 16.7 33.3

Hospital 1400 litre Blucher passive

InterceptorService Package with biological

treatment245.2 11.1 44.4

Café/Bakery 1 None FS05 Fatstrippa Active Interceptor 331 0 0

Restaurant 2 None FS10 Fatstrippa Active Interceptor 117 50 50

Sandwich Shop 1GreaseShield Mechanical

InterceptorNone 632.3 0 0

Comparison of systems

Design Conformity to I.S. EN 1825 Standards User Satisfaction Reliability

Maintenance - User Friendliness Ease of access Hygiene Odours Maintenance interval Contractor or in-house cleaning Waste

Comparison of systems

Performance Effluent sample analysis CCTV surveys (before and after) Blockage History (before and after) Level of Confidence

Cost To purchase To install To maintain

Outputs of Midleton Case Study

Statistics were compiled regarding the waste being removed from the systems

Better understanding of systems on the market in Ireland

Supplier/manufacturer procedures observed

Compliance with I.S. EN 1825 standards

Results of sample analysis

Outputs of Midleton Case Study

Maintenance procedures observed and rated

Contractor behaviour observed

Greater appreciation of all points of view

User Supplier Contractor

Outputs of Midleton Case Study

Greater understanding of kitchen practices Where most FOG is generated in different types of FSE Wok cooker, combination oven etc.

Tools for handling FOG related issues Ireland specific FOG letters Grease Trap Guidance sheets Kitchen Practice Guidance sheets Grease Trap Maintenance Record sheets

Observations - Licensing

Applications Site inspections Co-operation

Planning Department Environmental Department Environmental Health Officers

Guidance not available. Confusion caused by application form and

process. Resources

Observations - Licensing

Enforcement & Monitoring Site inspections required

Kitchen practices Maintenance practices

Co-operation Records

Disposal Blockages

Resources Method based consent

Observations - Disposal of waste

Cost Traceability Large quantities vs. Small quantities Facilities Clarity Lack of disposal records for waste FOG

(both by contractors and business owners). Contractors must be monitored

Observations - GRUs

Specification Sizing Operation & Maintenance IS EN 1825

Installation Incorrectly installed or situated traps. Appliances passing through grease trap.

Observations - GRUs

Maintenance Traps maintained incorrectly or not at all. Lack of knowledge of existence of GRU (Grease

Removal Unit). Forgery of grease trap maintenance records by

staff to avoid doing the work. Poor kitchen practices negating grease trap

maintenance.

Conclusions

Disposal of grease trap waste is a significant issue

Waste stream is dramatically increasing

Removal at source is most economical solution

Enforcement is necessary

Maintenance is vital

Education & Awareness

Conclusions (continued)

No one system is suitable for all sites

Challenge

Cost – Benefit

Cork County Council Report

WRc Reports MEng Sc Thesis: “Recovery of Waste FOG for use

as a Biofuel in Ireland”

Acknowledgments

Noel O’Keeffe - County Engineer, Cork Co.

Co. Matt Shortt - WSNTG

Tadgh O’Connor -DEHLG

Shane Kennedy -Cork Co. Co.

WRc Midleton Town Council Cork Co. Co. Environmental Section