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