Biofuels generated by wastewater treatment on farms, dairy plants, and other heavy industries can lower energy costs and lessen reliance on traditional fossil fuels.
By Dan Rafter
With the price of gas shattering records and electricity costs spiraling out of control in many parts of the country, the search for alternative fuels has taken on even greater importance. One potential source of these new fuels is plentiful, cheap, and an inevitable byproduct of farming and industry: high-strength organic wastewater.
A growing number of supporters are pressing US industries and governmental bodies to support the increased production of biofuels: solid, liquid, or gas fuels derived from recently living organisms or their waste byproducts. Corn, soybeans, palm oil, and animal waste are just some of the products that can make up biofuel. What makes these sources so attractive? They are all renewable resources, unlike petroleum or coal.
But one existing source of biofuel hasn’t received as much attention as its proponents say it should: industrial and agricultural wastewater with high organic content.
What’s puzzling is that this source of biofuels not only is plentiful but also brings with it a host of benefits to the industries and farms that tap into it. Farms, dairy plants, and heavy industries, for example, could all lower their monthly energy bills significantly by running their high-strength organic wastewater streams through treatment systems that generate methane biogas. These facilities could capture that biogas and use it to provide power to their machinery, lessening, at least somewhat, their reliance on traditional fossil fuels and their always shifting costs.
Some farms and manufacturers are already doing this. But many more that could are not. And that, say supporters of biofuels, is a terrible waste.
“We are still barely on the cutting edge of this technology right now,” says Josh Tickell, founder of www.biodieselamerica.org, a Web site devoted to promoting biodiesel, which is diesel fuel made from vegetable oil that can run in any unmodified diesel engine. “There has been a lot of discussion about this kind of fuel and technology for some time now, but no one’s really done much with it until recently.”
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Photo: Ecovation |
| High-strength wastewater can be used as a source to generate a type of biofuel. |
Tickell, who has also written a book about biodiesel and given lectures on the topic, says he looks forward to the day when biofuels of all types—including those created through the treatment of high-strength wastewater streams—are as common as petroleum is today. But that day is still far off, he says.
People, unfortunately, tend to ignore alternative fuels until the costs of fossil fuels begin hitting their pocketbooks hard. A shock such as $4-per-gallon gasoline—which isn’t unimaginable these days—might provide that extra boost in biofuel research, Tickell says.
“People see that fuel is more expensive. They then get more interest in actually having fuel grown by any means necessary,” Tickell says. “The effort to grow fuel not in traditional ways gains a bit of traction every time the price of gasoline goes up. I think what people want to see is us growing our own fuel. That is possible. I think it is possible for us to grow all our own fuel. That is the ultimate possibility.”
This discussion is an important one for the onsite wastewater treatment industry. Disposing and treating high-strength organic industrial wastestreams is always a challenge, with many factories shipping their waste to nearby farms, where they spread it across the soil to act as a powerful fertilizer. This is an acceptable use for wastewater. But when companies ship and spread it, they do have to spend extra dollars.
But if these same factories run their high-strength wastewater through anaerobic treatment systems, they can generate a significant amount of biofuel that they can tap into to run their operations. They are also able to reuse their treated, and now clean, wastewater.
It’s a system, then, that comes with a host of benefits: It saves industrial centers money, provides them at least some relief from unpredictable energy bills, and poses less of an impact on the environment.
For those companies that manufacture treatment systems that do result in wastewater-created biofuels, it’s essential to emphasize the monetary savings that industrial and agricultural clients can receive. By focusing on the long-term cost savings, these companies can more easily overcome manufacturers’ and farming operations’ initial unease regarding the upfront costs of installing such treatment systems—costs clients are, of course, not thrilled about paying.
“When we go to industrial customers, we always ask them to look at their high-strength wastewater. Then we ask the question, ‘Can we convert this into energy?’” says Dan Hagen, vice president of client development for Victor, NY–based Ecovation, a provider of anaerobic treatment systems. “In the meantime, by doing this, you can reduce your costs significantly. Not only will your plant be creating this great renewable green energy, but it will also see a cost reduction. That’s usually what gets us over the hump in the long run.”
Ecovation and other firms have made some inroads in promoting their anaerobic systems, which treat high-strength organic wastestreams and generate biofuel along the way. Each has its own individual success stories to share.
Ecovation, for instance, has provided its anaerobic system—its Mobilized Film Technology system—to the North Lawrence Dairy in North Lawrence, NY. The manufacturer is a cultured dairy processor of brand-name yogurt and cottage cheese products and relies heavily on No. 6 fuel oil and electricity as its main energy sources.
Ecovation in the summer of 2005 installed its Mobilized Film Technology anaerobic treatment system to treat segregated high-strength wastestreams and reduce the load on the facility’s current system.
So far, both tasks have proven successful.
The treatment system generates enough biogas to replace nearly 250,000 gallons of No. 6 fuel oil each year. This figure accounts for 25% of the plant’s usage. The treatment system also reduces the air emissions that the plant would otherwise generate from the burning of fossil fuels. The dairy even earned a $500,000 renewable energy grant from the US Department of Agriculture.
Jay Straight, engineering manager with North Lawrence Dairy, says that working with Ecovation made economic sense for the dairy. The dairy is using the biogas generated from the wastewater to fuel a small boiler, resulting in cost savings. At the same time, the dairy’s existing discharge aerobic system was prone to seasonal overloads, odor complaints, and high operating costs. The dairy’s Mobilized Film Technology anaerobic treatment system, which pre-treats segregated high-strength wastestreams, reduces the load on this aerobic system.
The anaerobic system has now been operating at North Lawrence Dairy for more than a year. So far, the results have been impressive, Straight says.
“We recognized that there was an opportunity for cost savings with this project,” Straight says. “And we’ve seen that. We’ve displaced the use of a significant amount of No. 6 fuel oil with the biogas. And secondly, it’s an environmentally sound adventure. It’s a green adventure.”
The dairy’s new anaerobic system primarily treats a wastestream that includes the byproduct from cottage-cheese manufacturing. The plant’s normal wastestream, which is far lower in organic materials, flows into the dairy’s aerobic treatment system.
Based on his positive experiences so far with anaerobic treatment systems and biogas, Straight says, he expects a greater number of dairies, industries, and agricultural entities to follow North Lawrence’s example.
“From my perspective, it all depends upon companies’ abilities to dispose of their waste,” he says. “If they have a high-strength organic wastestream that is not readily disposable, then, yes, I would think we’ll be seeing more of this.”
Before signing an agreement with Ecovation, the North Lawrence Dairy disposed of its high-organic waste through land spreading. The dairy would collect the waste, transport it to nearby farms, and spread the waste, which makes for good fertilizer, over the farmers’ fields.
This disposal method cost both money and time. And it did not generate usable biogas, as does the facility’s new anaerobic treatment system.
Looking at all the economic data, then, an anaerobic treatment system made the most sense for North Lawrence, Straight says.
“Part of the reason for doing this whole project was our limited capacity for aerobic treatment,” he says. “We were pretty much maxed out. Expanding the aerobic treatment would have been more costly than going with the anaerobic system. And it wouldn’t have produced the same benefits.”
This is the kind of success story that Hagen, from Ecovation, likes to hear. It’s also one he’ll tout when promoting biogas, and its ability to cut energy costs, with potential clients.
Ecovation’s Mobilized Film Technology turns highly concentrated wastestreams into methane gas, which clients can then use in whatever way they choose. The company’s system has successfully treated chemical oxygen demand concentrations ranging from 400 milligrams per liter (mg/L), common in municipal wastestreams, to more than 350,000 mg/L, which has occurred in acid whey from cheese processing. In these cases, the technology maintains a consistently low effluent concentration, low enough to meet most municipalities’ discharge limits without the need for additional polishing.
The Mobilized Film Technology treatment system has another advantage: Because it treats wastewater at a high rate of efficiency, the system itself is not large. Therefore, it does not occupy an undue amount of space. This is important for facilities that do not have much room to spare or for plants that are looking to expand and do not want to see potential expansion space used up by a wastewater treatment system.
The reactor at North Lawrence Dairy covers a footprint of about 2,000 square feet.
“What we are able to do is harness a tremendous population of bacteria in a very small footprint,” says Raj Rajan, an engineer with Ecovation. “An aerobic system that was built to handle the same amount would be five to 10 times the footprint. You’d also have to use more electricity to power it. You’d have more odor issues, too.”
Ecovation today is looking to expand its business, targeting mostly large industrial plants. In its early days, the company tackled projects at dairy farms, converting the farms’ highly organic wastestreams into biogas. That, though, is no longer a core business for the company. Today, Ecovation prefers working with large industry, taking high-strength wastewater from busy factories and turning it into usable methane biogas.
Ecovation has made a significant mark in the dairy-manufacturing business.
“We really do promote the fact that we can convert the high-strength wastewater stream from cheese and milk processing into methane gas,” Hagen says. “We can usually produce enough biogas for these facilities so that it represents 30% to 100% of the energy requirements at a given processing plant.”
As energy costs continue to rise, Hagen says, he expects more manufacturers to follow North Lawrence’s example. Companies will be more willing to take a chance on generating their own biofuels if it makes economic sense, he says.
“As costs have continued to escalate, it makes sense to look at alternatives,” Hagen says. “It especially makes sense when you are capturing and returning the fuel to the plant. Anytime you have to ship waste offsite, you incur more costs. The potential for cost savings with this type of project is significant.”
Looking Toward the Future
North Lawrence Dairy proves that it is possible and economical to create methane gas out of wastewater streams with extremely high organic content. Similar projects at farms, breweries, and heavy industrial plants do the same.
But biofuels are still far from mainstream. And biofuels created through the treatment of high-organic wastewater are even less common.
Industry analysts say they hope to see this change soon.
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| Breweries reduce energy costs from anaerobic digestion. |
“It is a spectacular technology,” says Jeff Coombe, a technical analyst with Salida, CO–based BBI International, a firm that performs feasibility studies for large-scale biofuel and ethanol plants. “It’s an excellent way to deal with waste. Right now, this waste is just carbon monoxide and other things we don’t want going into the air. Why not make it something that you can turn around and use? Problem is, it is a difficult road to go down.”
When Coombe looks at the biofuels industry, he sees wastewater-derived products, for now, lagging behind. Methane generated from landfill waste, for instance, seems to be a far more popular option, he says. The development and wide use of wastewater methane is far behind, Coombe says.
The reason? Coombe says that producing biofuel out of wastewater is a project that is capital-intensive. The costs of doing this, until they go down, may prevent some manufacturers and farming operations from considering it.
That’s not to say there haven’t been, and won’t continue to be, successes in the field. And like other analysts, Coombe points to spiraling energy costs as just one more factor pushing the country toward alternative fuel sources such as biofuels, including those generated through wastewater treatment.
People who expect too much too soon, though, are bound to be disappointed. Traditional fossil fuels still have a tight grip on the country.
“There is definitely more interest in technologies like this,” Coombe says. “But there are going to continue to be some growing pains. This is a difficult industry to do on a large scale. We use so much energy as a country, whether it be liquid fuels or energy for buildings that biogas could heat. The volumes are absolutely amazing. To find replacement fuels for that much volume right now isn’t possible. Everything we do is really supplementary. Replacement fuels for fossil fuels are a long ways off.”
Officials at BBI International, though, are committed to biogas and anaerobic digestion, Coombe says. The challenge is in getting others to make the same commitment.
“Once you have a proven product, you are set,” Coombe says. “Getting to that proven product point is the difficult road. I don’t know if people are leery because the process involves waste or if they’re leery just because it is something new that people don’t really understand yet. But once you do have enough examples to show that this does work, then I think people will certainly accept biogas.”
Another project involving wastewater and biogas should serve as at least one more example for farming and manufacturing operations.
The New Belgium Brewery, located in Fort Collins, CO, is the third-largest brewery in Colorado and the fifth-largest craft brewery in the country. It produces about 330,000 barrels of beer every year, or 13,000 cases and 1,310 kegs daily.
The City of Fort Collins had been charging the brewery what was known as a “plant investment fee” because the city had to process all of New Belgium’s high-strength wastewater in the municipal water system. New Belgium instead took the money it would have had to pay the city and purchased a process water treatment plant that included anaerobic digestion. New Belgium uses the methane produced by the digester to generate renewable electricity and heat.
The combined heat and power system—a 290-kW engine with heat recovery from Continental Energy Systems—has been in operation at New Belgium since 2003. Officials with the brewery say that it has saved New Belgium $3,000 in monthly energy costs.
Engineers studying the potential impact of biofuels point to such success stories as important steppingstones. The more stories such as the ones at New Belgium and North Lawrence Dairy, they say, the more accepting industries and agriculture will be regarding biogas created from wastewater.
Dan Rafter is a technical writer residing in Illinois.
OW- November/December 2007
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