Oil & Grease Removal. OWEA Collection System Committee HANDS-ON WORKSHOPS 9/13/07 10/11/07 Tom Horn Industrial Fluid Management, Inc.

Transcription

1 Oil & Grease Removal OWEA Collection System Committee HANDS-ON WORKSHOPS 9/13/07 10/11/07 Tom Horn Industrial Fluid Management, Inc.

2 FOG, where does it come from? Usually enters wastewater from washing of cookware and dinnerware Hot water between F Emulsifying agents are added Direct pouring of fry oils and grease down drains All result in high levels of FOG downstream

3 FOG, Where does it come from? Residential households Residents often have less care about what goes down the drain until the drain is clogged Many pump stations serving only residential neighborhoods still have severe grease issues

4 FOG, Where Does It Come From? Food Processors, Manufacturers From Previous Definitions, any facility that processes animals or vegetables Oil seed plants produce oils from soybeans, canola plants, sunflowers, etc. Any place that uses products from the above for frying, cooking, etc. Pretreatment Plants and Industrial Sources

5 FOG, When Does It Become Problem? Downstream sewer systems, FATS of animal origin are room temperature Often water temperatures are very high that keep FATS liquified Downstream that water cools down and solidifies.. Often in the first pump station Negatively impacts collection systems causing blockages or worse overflows!

6 Oil & Grease, Who Deals w/ It? Grease collectively known as Oil and Grease or Fats, Oils and Greases (FOG) Big Impact and probably has affected most, Operators Collection System and those who maintain those Pumpers and Cleaners Commercial Establishments Health Dep t Personnel / Regulators

7 FOG, Operations Usually issues with Plant Headworks Pumps and Check Valves Clarifiers, skimmers Biological Parts of Plants Digesters Collect it and remove from treatment What do you do with it

8 FOG, Collection Systems Mess with sewers (gravity and force mains) Mess in wet wells level controls, check valves, pump performance Often a potential source of odors where FOG accumulates Low ph and organic acids

9 FOG, Collection Systems WE&T Reports Nearly 50% of SSO s are from pipe blockages in Municipal Sewer Systems 47% of those blockages are due to excessive grease buildup in lines Approximately 25% of all SSO s are FOG related

10 FOG, Commercial Establishments Usually not concerned until if affects the business Drain blockages, odors Grease Trap this point the facility faces health issues and shut down

11 FOG, Regulators Potential Health Issues w/ Commercial Establishments (Restaurants) Health Dep t can shut them down Pretreatment Personnel deal with it with enforcement of grease trap maintenance Likely to become another Federal Priority

12 FOG, Pumpers Contractors that help industry maintain grease trap, skimmer tanks Go between originator and final disposal point Important to have a manifest system to document loads and origins of loads (even mixed loads) This is a regulatory type situation. Who handles it?

13 FOG, Fats, Oils and Greases, Fast Facts Many descriptions / definitions are interchanged among all 3 For our purpose today, we are focusing on FOG from plant / animal origin FOG is tested by the Hexane Extraction Method of Method 1664 Petroleum based compounds are analyzed by the silica gel treated method to separate Total Petroleum Hydrocarbons of Method 1664

14 FOG Fast Facts FAT consists of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water Can be either liquid or solid, Typically saturated (animal) are room temperature Typically unsaturated (vegetable) are room temperature these are often called oils Collectively all fats are considered lipids Lipids is the term for fatty acids, oleic, cholesterol. Also, major compounds of cell membranes

15 FOG Fast Facts Oil in a general sense, is a chemical compound not miscible with water and is ambient temperatures Hydrophobic water hating Lipophilic fat loving Oil refers to triglycerides Triglycerides from animals are saturated and room temperature Triglycerides from plants are unsaturated Sources (all seed oils and other oils extracted from plants and animal fat)

16 FOG Fast Facts Grease (yellow grease) refers to used frying oils from deep fryers and grease traps Lower quality grade of tallow from rendering plants (first candles made from tallow) Now becoming a source for yellow biodiesel

17 FOG, Grease Chemical Formula Grease is the term used collectively for all the previous items and their definitions Long chain fatty acids connected to a glycerol backbone Very high concentrations of BOD5, but very hard to break down due to the long chain fatty acids bond to glycerol. Very strong chemical bond.

18 FOG, Typical Values Wastewater from individual residences ranges mg/l (typically around 70 mg/l) Domestic WW Ranges weak to medium strength 150 high strength wastewater

19 FOG, Chemical Breakdown Triglycerides, consists of glycerol and long chain fatty acids Glycerol portion easily degraded and only 10% of theoretical value of FOG BOD5 Stearic Acid Palmitic Acid Oleic Acids Long chain fatty acids that are the most difficult to break down but contain the most energy values due to chemical structure

20 FOG, Chemical Makeup Very High Concentrations of BOD5 in FOG, but not highly degradable Another disadvantage of its physical characteristics Fatty Acids make it tough to break down COD values are easily in the range of 10,000-30,000 mg/l (5,000-15,000 mg/l BOD5)

21 FOG Problems Next stop that solidified FOG in lift station breaks off a little every now and then Congeals in downstream processes reducing pump efficiency, check valve operation Eventually gets to treatment process

22 FOG Problems Another Operational Issue Constant Skimming, Collection and Disposal Labor intensive and added costs Substrate to operational problems, foaming, scum and filaments that inhibit settling

23 FOG, Where does it come from? Restaurants and Fast Food Don t buy into the we only use preprepared food No matter what food is used Most FOG is from cleaning dishes, utensils, countertops and floors and hoods Where grease trap maintenance is not routinely performed

24 FOG Removal Grease Trap / Interceptor Rely on time and cooling FOG typically requires more than 30 minutes to naturally separate and float Cooling also helps for solidification, which aids in the floating of FOG Often flow from commercial institutions is instantaneous and 30 minutes is not met

25 Restaurant Grease Trap (kitchen style)

26 Kitchen Grease Traps Where you see these type run away as fast as possible Many tell you these never fill up, which may be true Too small, never get good separation of FOG from water Extremely warm due to proximity to sink and dishwasher and inside kitchens which are naturally warm. Liquefies much of what would separate Gas Station pizza outfits growing number of gas stations what are the regulations on them?

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30 Grease Tank ( in ground ) typical outside interceptor

31 Problems w/ Grease Trap Removal of free oil and grease Catches other stuff Cleaners and chemicals emulsify what would typically separate Simply not serviced frequently enough Need infrastructure to accept the amounts of grease that are floating around out there

32 FOG, Residential Based on 100 mg/l of FOG in domestic wastewater Neighborhood producing about 20,000 GPD of flow (about 200 people) x 8.34 x 100 = 17 lbs of FOG / day 119 lbs / week, 500 lbs / month, >6,000 lbs / year 30 lbs of FOG / person / year

33 FOG, Where does it come from? Food manufacturing Dairies, largely fats Bakeries, large and small use large amounts of oils and lard Seed oil plants, especially if little or no pretreatment Restaurants

34 FOG, How do we deal with it? Got an idea of what FOG is, its orgin(s) and what it can affect through sewer and wwtp s How do we manage and minimize its affects? Or how do we utilize or reuse its energy value?

35 FOG, How do we deal w/ it? Enforcement, more and more municipalities are writing strict ordinances on management of grease removal devices. This is already in place. Some municipalities are writing ordinances that deal with this. Outlining additives that are allowed for improving grease trap operation. Make sure emulsifiers, solvents or large concentration of surfactants are not allowed Biological Additives are successful but warn your customers about those that promise pumping is not necessary. No matter how much treatment you can achieve, solids and grease simply do not go away! Grease Trap achieves some biological degradation, but it s simply not large enough for consistent biological treatment

36 Municipal Regulations City of Lancaster, OH developed a Best Management Practices (BMP) handout for Food Service Industry Outlines cleaning practices dry vs. wet cleaning Maintenance of strainers, hoods and absorbents Regulated maintenance schedule on grease trap maintenance Daily / weekly for in kitchen units 90 day pumping cleanout of larger outdoor units.

37 FOG, How do we deal w/ it? Best option, get rid of it Pump grease traps, etc. often Issue w/ pumping, Where does it go? Watch out for the all to often blending if you already accept septage Regulations catch up w/ grease trap maintenance, manifesting will be necessary or the municipality enforces it

38 FOG, How do we deal w/ it? Richmond, IN Grease Reactor

39 Richmond, IN Grease Reactor Located about ½ way between Dayton, OH and Indianapolis, IN on I-70 Large amount of food and pet food processors in that area Issues with grease Superintendent Larry Baker noticed several years ago the need for proper grease disposal

40 Richmond, IN Grease Reactor Started from retrofitting old primary clarifiers w/ coarse bubble aeration Isolated high grease loads to this tank Found w/ aeration, detention time and bioaugmentation, the grease could be degraded Pretreatment prior to introduction into plant Basically, could treat it as sidestream to a point where plant was not negatively impacted

41 Richmond, IN Grease Reactor From that several year trial and the increasing demand for proper grease removal Came up w/ new idea Handles approximately 10,000 gallons / day. Septage still plant headworks 2 tank covered aerated reactor w/ biofilters for odor control By end of detention time flow goes right into raw influent without detriment to the system

42 Richmond, IN Grease Reactor

43 Richmond, IN Grease Reactor

44 Example of grease collection

45 FOG, How do we deal w/ it? If pretreated it has great potential to increase anaerobic digestion operation Already has VFA s and high COD values to increase gas production Has to also be blended properly to avoid grease cap in digester Need to make sure digester is not organically overloaded prior to increased grease addition Typically 80 lbs VS / 1000 cf. Some as high as 150 lbs VS / 1000 cf for anaerobic digestion.

46 FOG, Theoretical Energy Production Previously estimated 30 lbs of grease are generated per year per capita 30 lb x 85% volatile content = 26 lb VS from grease / year With 50% VS destruction = 13 lbs of VS destroyed / year 15 cf of biogas per lb of VS destroyed equals 195 cf gas / person / year from FOG 2000 people = 390,000 cf / year x 621 btu / cf biogas = 242,190,000 btu / year

47 FOG, How do we deal w/ it? Who wants it? If free oil could be cooked or spun out of it, biodiesel blenders could potentially use it Anaerobic Digestion systems for increased gas production Huge renewable energy source

48 FOG in Lift Station

49 FOG, Conclusion Handling of FOG and related issues is only going to grow Regulations catch up w/ major generators, Government (local, state and federal regulators) Energy Issues, more and more people are going to innovate ways to collect energy from grease trap wastes, not just used fry oils Public Education Offer publications / flyers on management of grease from household to commercial to industrial customers

50 FOG, Conclusion Questions and Comments Thank You!