Could poop power your home some day?
Well, Sanford, Fla., and MaxWest Environmental Systems Inc. of Texas have teamed up to convert the city's stream of wastewater sludge into renewable energy.
The goal is to take everything the good people of Sanford send down their toilets and sinks and turn it into energy, instead of sending it to landfills.
The city dries 30 tons of sludge daily with a natural gas-powered dryer and then hauls the biosolids off-site for disposal. But under a new $3.5 million gasification system, the sludge will be converted into thermal energy, which will replace the natural gas to power the dryer.
The new system is not only greener, it could also save the city $9 to $14 million for the life of the 20-year contract, according to MaxWest.
"There are a variety of disposal systems. The traditional ones have been to dump it ... or put it in a landfill," said Bill Baker, vice president of marketing for Houston-based MaxWest. "We don't know of any other gasification system in North America operating on sludge."
Energy From Waste Could Power 1,500 Homes
In two years, the company hopes the same technology used in a different part of the state will create enough power to supply the needs for 1,500 homes.
"The primary driver is to get rid of a tremendous amount of horse muck -- manure, straw and wood chips -- used in the thoroughbred industry," Baker said of the project in Florida's Ocala County.
Using the same gasification system, the company intends to produce about 10 megawatts of power, which will be sold to the local power grid.
Allen Hershkowitz, a senior scientist with the New York City-based Natural Resources Defense Council, said that although there have been attempts to gasify waste and convert it to energy, they've generally been smaller-scale research and development projects.
"We don't have a lot of experience with the gasification of biosolids for energy recovery," he said.
Although he was not familiar with the details of the Sanford project, he said it seems to be an innovative approach as long as toxic prevention controls are also in place.
Projects Across the World Experiment With Poop Power
A range of pollutants, such as copper, cadmium and chromium, could result from the gasification process, he said. But with proper controls and oversight, they could be contained.
MaxWest's Baker said the gasification facility uses industry-standard clean technology to capture toxins released during the process. He also said the system is engineered to mitigate the polluting emissions and that many chemicals are destroyed by the sustained time at high temperatures.
"This is a technology that is needed," scientist Hershkowitz said. "They do have some energy value and if we could recover energy from it and also reduce the mobilization of pollutants, that might be associated that would be a good thing."
Although MaxWest's gasification system is new to the United States, many others around the country, and around the world, are experimenting with poop-to-power projects. Here are four examples.
Anaerobic Digesters Turn Waste Into Energy
Phil Zahreddine, a branch chief with the Environmental Protection Agency, said that although gasification is not common in the United States, it could prove to be one more way to cut back on fossil fuel.
"There's a big tendency in the United States and Europe and the rest of the world to shift from fossil fuels to renewable energy," he said.
One of the more common methods of harvesting energy from waste is using anaerobic digesters.
This process uses organisms to break down biodegradable material in the absence of oxygen to produce biogas. That biogas is then used to power electric-generation equipment, like fuel cells or micro turbines.
Of about 16,000 public wastewater plants in the country, Zahreddine said 544 use anaerobic digesters. Of those, 106 use the biogas for heating processes or electricity.
"What is interesting is that as more projects are coming online and the technology is becoming more efficient, these options are becoming more attractive to facilities," he said.
Waste 'Electrifies' City of Los Angeles
Los Angeles was recognized last month for its own project to turn biosolids into clean energy.
Named as a semi-finalist for the 2009 Award for Innovations in American Government by the Ash Institute for Democratic Governance and Innovation at the John F. Kennedy School of Government at Harvard University, the Terminal Island Renewable Energy (or TIRE) project involves injecting sludge into a mile-deep well.
At that depth, Earth's high temperature biodegrades the organic compounds to create methane gas. The process also traps greenhouse gases and prevents them from damaging the atmosphere.
By 2012, the project is expected to produce about 3,500 kilowatts of renewable power, which could power thousands of homes.
"This renewable energy project is absolutely electrifying," Los Angeles Mayor Antonio Villaraigosa said to the Los Angeles Times. "It will save money and make money."
California Dairy Runs Trucks on Manure
Earlier this year, Hilarides Dairy in California said it converted a pair of 18-wheelers to run on cow manure.
The dairy uses manure produced by 10,000 cows to generate 226,000 cubic feet of biomethane. Methane is a natural byproduct of the process that breaks down sewage.
"For us, it made sense to invest in this technology. Now we can utilize the dairy's potential to power our trucks, in addition to generating electricity for our operations," Rob Hilarides, owner of the dairy, told The Christian Science Monitor. "This will significantly reduce our energy costs and give us some protection from volatile energy prices."
To produce the fuel, the manure and other waste from the cows' stalls are flushed into a lagoon where bacteria breaks it down. Methane is then pumped out of the lagoon to a refinery that removes carbon dioxide, hydrogen and other impurities.
The purified methane is pressurized and then pumped into the converted trucks.
The cow manure-produced bio-methane not only produces less pollution than conventional fuel, the production of it also reduces the amount of methane released into the atmosphere by the manure itself.
Norway Plans to Run City Buses on Human Waste
In January, the city council in Oslo, Norway, said that as part of its plan to cut greenhouse gas emissions and become a carbon neutral city by 2050, it would convert city buses to run on a byproduct of treated sewage: biomethane.
Starting in September, the gas released by microbes that break down the raw sewage will be captured and converted into biomethane to run 80 public buses.
If the plan is successful, the city will convert all 400 city buses to run on a biogas created from a mixture of biomethane and biogas from the incineration of kitchen waste from the city's restaurants and kitchens.
"The city of Oslo has great visions for Oslo as a green capital," project leader Ole Jakob Johansen told the U.K.'s Guardian. "Oslo aims to be one of the most environmentally sustainable capitals of the world. Using biomethane makes sense. Not only would the biomethane otherwise be wasted, but the reduction in emissions per bus will go a long way to achieving our carbon-neutral target."