Fog & Our Nation's Sewer Systems
Logic demands that you must frame a problem before a solution can be defined. The problem and subject here is Grease. And we are not referring to the hit movie or Broadway play. We are referring, rather, to Fats, Oils, and Grease (FOG) from restaurants—waste products that increasingly enter the collection systems and sewer lines in the U.S.
In the past few years there have been a number of high-profile print articles on the damage and expense of kitchen-derived grease congealing in our sewers and contributing to thousands of sanitary sewer overflows (SSOs) in our cities and towns. These overflows result in a damaging runoff into our rivers and streams, compromise our recreational and drinking water supplies, and impact our groundwater.
In 2001, Barry Newman, arguably the premiere feature writer for the Wall Street Journal, crafted an article that became a focus piece for an entire industry sector that is working to provide efficient products and services for the collection, removal, and treatment of grease waste. His thesis was, essentially, that we are at war with grease.
The issue is that an especially environmentally challenging grease from kitchens around the country enters our sewage collection systems and, like cholesterol in arteries, accumulates and ultimately closes them completely.
In combined sewer systems (sanitary and storm sewer systems using the same infrastructure—CSS), heavy rains add to the total sewer load, and the clogged systems react to this “capacity crisis”: the sewers’ marginal remaining capacities are exceeded, the contents have to go somewhere, and the problem emerges—literally. As much as 40% of sanitary and combined sewer overflow to the surface environment has been attributed to clogged pipes due to excessive grease buildup.
Impacts of regulating FOG generators
In the past few years there has been tremendous growth in the number of restaurants in the U.S. (over 900,000 with $476 billion in sales); a consequence of the trend of Americans eating out more frequently every year. The growing number of food service establishments produces increasing amounts of brown grease, an exceptionally sticky and difficult-to-manage waste. Restaurant grease interceptors or grease traps (collection devices in a commercial kitchen’s plumbing system) produce brown grease.
The volume of this material and its impact has triggered increasing regulation with respect to restaurants, FOG generators and FOG haulers—the latter being the service-sector operators that collect this type of waste and dispose of it.
On the haulers’ side, regulations now often require them to remove the entire contents of the grease interceptor (perhaps 1,000 gal per trap) instead of the historical practice of removing only waste grease and food solids. The old process left the “gray water” in the interceptor (taking away perhaps only 200 gal per trap). The result is four to five times the volume of material, much of it greasy water, that needs a disposal option.
This so-called “full-pump” requirement is a key to the increasing problem of brown grease in America.
Indeed, most city and town pretreatment coordinators (grease interceptor regulatory officers) have agreed that this new policy, focused solely on brown grease management through strict regulation of the generators and haulers, has negatively affected the economics of the hauling industry and has increased the frequency of premeditated environmental violations. The cause and effect explanation for these two related consequences is convoluted, but essentially logical.
In many cases the interceptors hold 750 to 1,000 gal, and up to 85% (and sometimes more) of the tank contents are water. All of this needs a home after it is pumped.
However, many local treatment plants have found that they can’t handle grease at all or cannot accept the new amounts being offered for disposal. Consequently, they are forcing haulers to drive farther to discharge their loads to other, more distant facilities for treatment. This has had a huge economic impact on the hauler with the cost of fuel, insurance, and labor continuing to climb and the ability to generate revenues limited by fewer “pumps” on a service route (full pumps means more volume per pump and fewer pumps can go on each truck before offload is needed). Resistance of generators to accept the pass-through of higher hauler costs has caused some haulers to look for alternative ways to discharge. In some cases the alternative is decidedly illegal.
Discharge of waste into storm drains, fields, sewers and estuaries has become an issue for the EPA and for all haulers who are looking to do what is right yet remain solvent.
In conversations with haulers across the U.S., a common thread is that haulers are losing money. Why? Unit disposal costs continue to rise along with a substantially higher cost of transportation to the final disposal facility or plant.
FOG and the treatment plant
Not surprisingly, given the public visibility, cities and towns across the U.S. are moving to reduce the number of combined sewer overflows and sanitary sewer overflows by setting up new rules for food service establishments.
According to Tony Russo of the Passaic Valley Sewerage Commissioners in N.J., their treatment facility in Newark accepted hauled grease collected from traps and interceptors in such volume that the material became a huge nuisance for their treatment facility. It cost over $38,000 per month per screen on maintenance alone—and there are many, many screens.
At one point, according to Russo, “We advertised for grease and collected it from all over the northeast.” That amounted to over one million gal per month.
So when the agency abruptly stopped collecting it for financial reasons, nobody knew where all that diverted grease was going. New York City alone has over 24,000 restaurants and Passaic Valley was the disposal point for much of the New York restaurant grease. The mystery of actual disposal remains, but intuitively the answer does not inspire confidence. However, there are instructive conclusions from this analysis.
Here are some lessons to be learned at the plant:
- Interceptor grease is not the same as septage. The cost per gallon to treat it is significantly higher than the per gallon charge to treat sewage;
- The personnel time devoted to WWTP grease issues is disproportionate to the volume of material handled;
- Simply blending in the interceptor grease and assuming it will not be seen in the larger picture of plant management is a mistake. There are serious conse- quences of intensely managing the actions of the generators and haulers on the front end of the regulatory equation with no disposal options on the back end of the equation;
- Given no place for disposal, grease will escape and be disposed of in streams, fields, woodlands and wilderness; and
- What doesn’t escape may enter the WWTP through the back door, by illegal dumping into obscure sewer manholes or lift stations.
Pretreatment coordinators are implementing new procedures for the collection of grease prior to it entering the collection system. Some of the steps they have taken include proper sizing based on the number of meals served, frequency of servicing, and setting the frequency of grease trap and grease interceptor inspections. The adopted regulations give the cities and towns enforcement options, including the imposition of fines and other penalties for those out of compliance at the generator level. Yet after all of that, we have created another monster. What do we do with all that grease? Because grease is the cause of blockage and sanitary sewer overflow, cities and towns are giving top priority to establishing effective FOG programs.
An effective solution
EcoPlus has a solution for the disposal and processing issues facing communities and haulers. The technology has been used in commercial application since 2002 at a fully permitted plant in Charlotte, N.C. The plant processes brown grease from over 1,300 grease producers in the southeast, providing over 3,500 service calls per year.
The EcoPlus Final Treatment Facility, using EcoPlus’ unique technology, can be set up at the WWTP or in a remote location, can handle the grease with virtually no impact on a WWTP, and can discharge the supernatant water from its process back into the city sewer, meeting virtually any discharge quality requirement.
In larger cities where hauling to an acceptable location can require traveling over 60 miles, an EcoPlus Preprocessing Center collects the FOG and food solids and discharges a relatively high-quality water back into the sewer system. The grease concentrate is then shipped for processing at an EcoPlus Final Treatment Facility.
The process produces two waste streams. One is a low-strength aqueous solution that is easily disposed of into a sanitary sewer tap. The second is a granular material that can be disposed of in a landfill, used as a soil conditioner (EcoSoil) or used as a compost amending agent beneficial to fungi, thus facilitating cellulose breakdown. This granular material can also be used as a moderate BTU fuel to facilitate incineration of sewage sludge (EcoFuel) and most intriguingly, burned as an alternative green fuel for power generation. As such, it has been tested for this purpose in a large-scale burn at a regional power plant with excellent results.
The solids meet 40 CFR 503.33 standards for vector attraction reduction.
Financing with offsets
In terms of cost, EcoPlus can assist in obtaining financing and leasing options, structured specifically for public entities. For this financing scenario, reduced SSO fines, maintenance savings in both plant operations (screens, clarifiers, etc.) and collection systems (jetting, lift station pump and float maintenance, etc.) are legitimately considered as offsets and are applied to the financing equation. The concept is to transfer savings on maintenance and fines to offset acquisition costs.
In many cases, offsets can be combined with plant use fees—such as user fees and tipping fees—to provide for the acquisition of a plant free of any additional appropriation from general funds. If offsets and fees are insufficient, the funding package may be combined with one or more funding sources.
Final points on policy & technology
As noted at the beginning, you must frame a problem before a solution can be defined. We have not framed the entirety of the brown grease problem, but we have outlined some current environmental issues and associated regulatory constructs and their consequences. We have demonstrated that in this situation, public policy and private technology are linked.
Policy constructed solely around regulating the generator and hauler of brown grease, without including statutes for promoting technology for the final disposal of brown grease, has widespread negative impacts. The “Law of Unintended Consequences” is alive and well.
Fortunately, in this case and for this problem, there is a robust, operationally-proven, commercial-scale technology now available. This technology, which accepts high volumes of brown grease and processes it into value-added products—including a green fuel product—is alive and well.