Bioremediation provides restaurants with a nonhazardous, environmentally friendly way to deal with grease traps and drain lines clogged up by fats, oils, and grease.
By Lori Lovely
The growing tendency for Americans to eat out more frequently has contributed to the growth of the restaurant industry. According to a National Restaurant Association report in 2006, more than 925,000 restaurants are in operation across the nation, logging $511 billion in annual sales. The amount of fats, oils, and grease (FOG) the restaurants discharge seemingly reaches comparable numbers.
More restaurants means more grease traps and drain lines clogged up by FOG—in particular, especially sticky brown grease unsuitable for reclamation for biodiesel production. To protect downstream ecosystems, as well as to prevent backups in restaurant drains that can lead to health hazards, federal officials have imposed increasingly stringent regulations controlling wastewater output. In response, the food industry has turned to a wide range of chemicals, enzymes, microbes, and other solutions, with varying rates of success.
David Johnson, managing director for BioStim in San Antonio, TX, notes that enzymes are prohibited in most cities because they’re impossible to monitor. They merely liquefy fat, separating the grease molecules, which eventually re-coagulate downstream, he says, where they cause further problems.
Coming Up With a Winning Combination
“Mother Nature can rectify the situation with time,” muses Susanne Homer, president of Clean Water Solutions, based in Newport, RI, “but we humans don’t want to wait that long, so we look for options to take care of the problem immediately.”
Prominent among those options is bioremediation, a process that uses microbes to recycle organic materials and return an environment altered by contaminants to its original condition. Collected from natural water and soil sources, microbes require oxygen, water, and food. Once activated by water, they begin consuming hydrocarbon-based pollutants, leaving behind them only carbon dioxide, water, and trace amounts of carbon, fatty acids, and bacterial cells.
Benefits of bioremediation, according to Benny Maresca, technical director at Biological Solutions in Sumter, SC, include the nonhazardous, environmentally friendly reduction of insects thanks to the removal of the breeding ground (grease); the removal of odor from food and other material rotting in trapped grease; and the removal of blockages from trapped grease and foodwaste. In addition, he says, replacing hazardous chemicals with natural microbes can sometimes decrease insurance costs. Additional cost savings can occur because of the reduced need for pumping and cleaning.
However, Kerry Smith, national sales manager for Hydro Engineering, based in Salt Lake City, UT, considers bioremediation a misused term. “Remediation means removing. Treatment is an expected outcome on a consistent basis. We do water treatment and recycling.”
Whatever you want to call it, the key to curing a FOG problem is proper elimination. As Homer alludes, bacteria predate humankind and are nature’s way of cleaning up after the Earth’s flora and fauna. But, according to Hydro Engineering, naturally occurring bacteria necessary for eliminating FOG aren’t often found in high enough concentrations to obtain sufficiently fast breakdown. Therefore, as both Smith and Homer correctly state, humans turn to biodigesters to speed the process. “You need enough bacteria centralized to do the job quickly so the bad, unsafe bacteria don’t find a home,” Smith elaborates. “Bacteria reproduce so quickly, they will soon overwhelm the situation.
“By supplying enough viable strains of bacteria with the targeted enzymes in one location, the substrate is overwhelmed and consumed quickly.”
Not only are there plenty of them; they are also the right mix of bacteria. Each bacterium corresponds to a specific substrate. However, bacteria adapt and acclimate to an environment and a substrate, or food source, rendering them less effective over time. In addition, even though all bacteria produce enzymes, they may not produce the proper enzymes to ensure efficient breakdown of the substrate.
“Some products make claims that their bacteria create enzymes,” Smith warns. “All bacteria create enzymes, but do they create the right enzyme? Enzymes are like the chef that prepares a meal for the bugs. It takes the right enzymes to break down the substrate.
“Customers need to know that when you buy a product, it better be targeted or it’s a waste of money,” he continues. “You need lab-grade purified enzymes. You need micro- and macronutrients. They keep the enzymes healthy and prolific so they’ll continue to work efficiently. Bacteria have a life cycle of about 14 days; they don’t last forever. Each generation becomes subsequently weaker and less effective because it becomes specialized to a particular food source. You need to add new strains; you must re-introduce bacteria periodically.”
Clean Water Solutions uses naturally occurring microbes from the Archaea family, a combination of more than 100 strains that can adapt to various situations, to remediate hydrocarbons like oil and grease. Listed on the EPA’s National Contingency Plan, they are considered the most powerful microbes known. Homer explains that the nontoxic, nonpathogenic microbes work well on cutting and converting FOG into water-soluble, beneficial fatty acids, which are food for fish and plant life, and that they pretreat water as it goes into the land.
“There’s no chemicals, no caustic lye that has to be stripped out of the water downstream,” Homer says, adding that the Archaea microbes can be safely used in a closed-loop, septic, or municipal system. “[Businesses] use a lot of chlorine, but that’s troublesome. It’s hard to get out downstream, it’s not environmentally friendly, and it kills friendly bacteria.”
Bleach is a scam, Maresca charges. “It doesn’t kill a lot, but it’s a problem at small facilities like nursing homes and restaurants, because in smaller systems it fries the microbes so there’s no biological degradation.” In fact, bleach coagulates grease and has a negative effect on mold. It’s an even bigger issue with wastestreams, he adds.
At restaurants and nursing homes where odor is a bigger issue than blockage, chlorine reigns. “People like the smell of chlorine because it makes them think things are clean,” Maresca elaborates. Biological Solutions is trying to educate the restaurant industry that workers shouldn’t dump a bucket of bleach down the restaurant’s grease trap to counteract the odor. “Education is extremely important because bleach undoes a system. It’s a staple of the restaurant industry, but it doesn’t work well. It’s corrosive, and it emits fumes. It’s also unproductive downstream because it kills everything else. Hospitals don’t use it because of the toxicity; they use ammonium salts.”
That’s why Maresca is trying to convince restaurants that they “have to have a blend of hardy microbes to start degradation.” The wastestream determines what kind of microbes make up that blend. “You need different formation broths to deal with different streams, such as sanitary, food, and even diesel spills.”
It took BioStim a long time to develop the right formula, according to Johnson—a combination of bacteria for the whole process. “There are six strains in our formulation. We selected the most efficient bacteria to eat grease.”
For proper bioremediation to occur, the environment must be conducive with a food source, air, water, and the right temperature range and pH. “They can’t take extreme heat; they have a temperature tolerance of 55 to 105 degrees. Below 55, they’re sluggish. Below 28, they’re dormant. Over 120, they perish,” explains Homer.
Smith counters, “Different products produce different contaminants. Animal byproducts produce FOG; grains create different problems that require a different approach and different products to treat. You have to target a substrate; one bacteria won’t eat all food sources.”
There are 15,000 forms of bacteria identified and more than 3,000 known bacterial strains, Smith states. They fall into one of three categories: anaerobic, which doesn’t require oxygen; aerobic, which needs oxygen; and facultative strains, which are able to switch back and forth. In addition, bacteria must be able to tolerate disinfectants.
Beating the Bugs
“There’s a fear in food production of pathogens that cause illnesses,” Homer warns, “and grease traps are a huge issue in that regard.” Daily use of microbes can ward off pathogens—and other problems—easily and economically. “Restaurant owners like it; they don’t need their traps cleaned out as often. It’s a paradigm shift from Clorox.”
It’s also simple, she insists. “Use it at the end of the day: Treat it with lukewarm water, turn off the lights, and go home.” Clean Water Solutions’ microbes come in a powder form using a clay carrier. The microbes lie dormant until activated by oxygen, a food source, and water. Then they multiply, doubling every 20 minutes. The benefit, Homer explains, is that the microbes consume the food source. When they no longer have a food source, water, and air, they die. There’s no bacteria bloom.
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Photo: BioStim |
| Liquid and powder treatment options abound for FOG. |
BioStim makes it easy with a new product introduced in September. MicroDrip is an innovative injection system for use in food-service facility drain lines. The small injection unit allows bacteria to drip into drain lines in concentrated form every 15 minutes, providing consistent microbial treatment to maximize FOG reduction and such FOG-related issues as odor, insect feeding and breeding, slow drain lines, blockages, and backups.
MicroDrip reduces grease buildup in drain lines and grease traps by regularly dispensing time-released bacteria via inexpensive “plug and play” cartridges. The concentrated formula reduces more grease, which Johnson cites as the number-one problem.
The new system isn’t a replacement for grease traps, he cautions. “We’ll never get away from them.” MicroDrip’s primary business is to treat drain lines. “It’s a supplement to wastewater treatment. We’re able to reduce the amount of what’s in the effluent, especially FOG, but it’s only part of the solution; it’s not the solution. Our system keeps grease to a minimum, but if the grease trap is undersize, we’re not trapping anything.” Nevertheless, he adds, onsite treatment remains the best option.
Bugs in the System
The trick, according to Maresca, is keeping ahead of a wastestream that is constantly changing. “There are a lot of xenobiotics—manmade ingredients and synthetics that the microbes can’t digest. It’s becoming a bigger issue all the time, especially with the anti-microbial soaps on the market.”
Biological Solutions is busy in the lab testing new xenobiotic products. “Research shows that we need to address products with tough-to-kill ingredients,” Maresca relays, “and with each new wastestream, we have to change how we deal with it.”
Business owners must also do some research to find the right product for their applications. “It’s the wave of the future,” Smith firmly believes. “Check test results; look for testimonials.”
He offers suggestions about finding the right product and the right company. “You’re buying cell count when you buy bacteria. If a manufacturer doesn’t guarantee the cell count, don’t buy!”
The problem is that restaurants usually buy from food or chemical suppliers who don’t understand the technology, Smith says. “They think a product works because the grease trap is clean. But a lot of times if they get tested, they get fined.”
They aren’t the only ones receiving fines. Plants, pumper-haulers, and businesses that find it difficult to comply with increasingly stringent requirements often pay the penalty. Sewer treatment plants are typically located at a discharge point. The EPA gives them criteria to meet, based on the kind of water body into which the effluent will be discharged. The plant then designs around the number of constituents it serves. When growth occurs, loading increases: It’s harder to treat waste when a facility is at capacity. In reaction, many plants try to tighten discharge regulations. Some businesses find it easier to pay a surcharge—a tax on excess waste—than to take the steps necessary to meet the limitations.
Alternative Ending
Rather than worry about downstream problems arising from improperly treated wastewater contaminated by FOG, EcoPlus Inc. has devised an alternative strategy: a turnkey package for processing oil and grease into a value-added product. The idea is to dispose of brown grease, fats, and oils generated by the food service and production industry, converting the waste into granular material for use as a soil-amending agent in agricultural applications or as an alternative fuel. And, says Chief Operating Officer Bill Scherffius, if there’s no use for it, it can go to a landfill with no special issues because it’s nontoxic.
“The material from restaurants collected by private haulers is brown grease, not the yellow grease used for biodiesel,” Scherffius explains. “It’s increasingly difficult to dispose of: Wastewater treatment plants don’t want it, and land application sites are becoming few and far between. It’s an environmental issue. This material has no home.”
The material does have value as an alternative fuel, and Scherffius believes the push for alternative fuels will boost the industry. “We finally found a home for this residual product. There’s interest from organizations with requirements to use alternative fuels. Currently there are 24 states that have voluntary or mandated requirements for utilities to use renewable fuel.”
The patent-pending, low-cost process of converting waste into an alternative fuel product involves a chemical process whereby a “plant receives 100% of the stuff from a grease trap: FOG and water. It’s mixed with chemicals before going into a batch reactor where the water is removed and fed into a sanitary sewer cap. Approximately four hours later, a solid product with the consistency of damp beach sand is produced.
“We first considered [the resulting product] as a soil amendment because of its high lime content,” Scherffius says, “but we found it has a Btu value of 6,000 or more.” That’s roughly the same Btu value as various styles of coal; in fact, EcoPlus calls its product “white coal.”
“We did a test burn at a regional facility—cofired it with coal in a less-than-5% mix,” he explains. “It requires no changes in the equipment, its fuel value matches coal, it has a lower sulfur content than coal, and its lime content produces beneficial ash that helps emissions.” In addition, he adds, its conversion process is environmentally friendly because it uses gravity instead of heat and pressure.
With a footprint of approximately 50 feet by 100 feet to 150 feet in a standard steel building, the turnkey plant can be set up at the customer’s site or a convenient location. It provides a significant rate of return: roughly 4 tons of solids at 6,000 to 7,000 Btus for every 4,000 gallons put into the reactor. EcoPlus customers can even charge a tipping fee on the front end from haulers in addition to generating income from the material produced.
The FOG Is Lifting for a Clear Future
Whether FOG is converted into fuel or simply mitigated, it needs to be addressed. “There’s too much grease going into the municipal water system, so there’s a backlash from municipalities,” Homer says. “But if we pretreat at the source, we can eliminate the issue before water even gets to the treatment plant.”
Homer calls the process “biostimulation” and augmentation that assists the natural cleanup work and replaces the “dig and haul” method of bioremediation. “It kills odors without chemicals to accelerate and assist Mother Nature.”
“It makes sense that cities like Woodbridge, New Jersey, require products like ours in restaurants as preventive maintenance,” Johnson asserts. “As time goes on, it’s going to be like pest control: It will be required everywhere.”
However, a catalyst often is required to initiate regulations and change habits. With bursting steam pipes in New York and falling bridges in Minnesota, Americans are directing attention to the aging infrastructure. Concern for municipal plumbing and wastewater treatment plants is building, and the connection between what we pour down our drains and what we pour from the tap is causing a shift in thinking about the processes and products we use to treat our water.
Homer believes the political climate is right for further development of a microbial solution to FOG. “Ten years ago, I couldn’t have built this business, but with Al Gore’s movie out [An Inconvenient Truth], people are reconsidering options.”
But it’s a tough hill to climb. Homer cites the one-and-a-half to two years it takes for “significant uptake” of the information spread at trade shows and through direct-market pieces, lamenting the lag time in getting the message to the consumer. No matter how educated corporate heads and distributors are, distributors don’t carry products until there’s a demand for them—and that takes time, Homer says: an additional three to five years.
Market statistics show that 80% of business owners are interested in paying a little more to address the problem in an environmentally friendly way. The next 10 years will provide an opportunity to convert from traditional chemical processes to more organic ways.
“We made a decision to be part of the solution,” Homer states. She wonders how many others will make the same decision.
Residing in Indianapolis, IN, Lori Lovely writes authoritatively on transportation and technical subjects.
OW - January/February 2008
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