1 of 2

Why consider FOG Energy?

Case Study: Innovative receiving system for Fats, Oils, and Grease (FOG) installed at Millbrae, CA wastewater treatment facility enables continuous feeding of high strength organic waste into anaerobic digesters, successfully.

Goal: Millbrae’s treatment plant sought to augment anaerobic digester feedstock for enhanced and steady state biogas production to create more of their own plant operation energy and other resulting benefits. Challenge: How to manage receipt, conditioning, and feeding of FOG into the anaerobic digester system to mitigate the difficulties of handling FOG and achieve steady state biogas production?

Results: Provides new revenue from tipping fees Reduces / eliminates costs associated with:

FOG handling labor Energy purchases Secondary system operation Biosolids dewatering and disposal Plant chemical usage

Avoids the adverse biological reactions that result from commingling concentrated organic wastes with treatment plant influent

Eliminates resource waste by avoiding ebb and tide biogas production with continuous steadystate feeding for biogas production

Does not diminish stability of digester operations or sludge dewaterability

Reduces the amount of sewage solids that require dewatering

Creates a sustainable decrease of biosolids disposal volume by reducing the amount of sewage solids that require dewatering

Automatic control minimizes unnecessary operator input

No pipeline plugging observed No extraordinary housekeeping needed

Background: The facility serves a population of ~22,000. The average daily flow is 1.6 MGD. Liquid stream treatment processes include grinding and pumping, primary sedimentation, conventional activated sludge incorporating anaerobic selectors, secondary clarification, chlorine disinfection, and dechlorination. Solid stream treatment processes include centrifugal grit removal, gravity sludge thickening, thickened sludge screening, anaerobic digestion, and belt press dewatering, with final land application disposal. The facility did not produce enough biogas to support financially modern CHP equipment without augmenting digester feedstock. Since operations began in January 2007, the Millbrae FOG receiving system has performed with minimal operational problems, no odor complaints, and excellent results. While monitoring very carefully for nearly two-years, Millbrae POTW staff is unable to identify a downside of managing the introduction of FOG into their anaerobic digester with this system.

©2009 FOG Energy Corporation

2 of 2

816-460-5410

Environmental & Societal Benefits: Enables production of renewable energy from non-toxic waste materials Helps reduce the nation’s reliance on foreign oil Helps release energy resources contained in wastewater solids Provides grease waste haulers with an environmentally beneficial disposal option This disposal option complies with current regulations Potential eligibility for various rebates, credits, grants, etc.

©2009 FOG Energy Corporation

For further information, please contact:

info@fogenergycorp.com

Or Call: 530-638-5466 for technical inquiries

408-315-4242 for business discussions

Turning Inedible Kitchen Grease into Renewable, “Clean Energy”

“The controlled introduction of FOG into an anaerobic digestion system is a critical component in any FOG program.”- Dick York, Former Superintendent

The System: High strength non – toxic organic waste (in this case FOG) collected from grease traps, interceptors, and sumps is transported to the Publicly Owned Teatment Works (POTW) facility where receiving system equipment removes it from a tanker truck, treats it by removing inert debris (rocks, etc.), reduces the particle size, and deposits it into a conditioning tank. We theorize that intense microbial

competition and short detention time (less than one day) naturally suppresses methane production. These same biological reactions also change the character of grease to alleviate the many objectionable handling difficulties including stickiness and odor. The resulting slurry, loaded with VFA, rapidly converts to methane resulting in steady state biogas production when continuously introduced into a healthy anaerobic digester. Odors emanating from the conditioning tank are negligible after passing through a biological foul air scrubbing system. NOTE: Effective anaerobic digester mixing is essential with use of this system to accomplish required anaerobic digester performance to achieve expected biogas production [reference US patent # 7,485,230].

Millbrae, CA FOG receiving system