In hindsight, it was little more than modern alchemy, “a technological crap game,” a massive mistake that burned half a billion public dollars.
Convert sewage sludge into clean-burning energy.
In the 1980s and ’90s, officials in Los Angeles spent some $500 million on two plants that were supposed to do exactly that. But what was elegant in theory turned out to be horrific in reality – abrasive sludge ate through valves, clogged pipes and erupted into flames so hot they took days to extinguish.
The city of Los Angeles’ plant scrapped the technology at the heart of its waste-to-energy idea and went with something simpler. The Los Angeles County Sanitation District’s plant never went online.
So it is with some déjà vu that officials are now touting the idea of converting sewage sludge to energy. This time, a private company is taking the financial risk of designing and building the plant, not taxpayers. Times – and technology – have changed, officials said. They believe the outcome will be very different now. But still, no one is completely sure – not even renewable energy company EnerTech Environmental, the one taking the risk.
“Can SlurryCarb successfully treat biosolids?” asked a report commissioned by EnerTech in 2005, examining the differences between the failed Los Angeles experiments and its patented SlurryCarb process.
“This question will not be answered definitively until the process is designed, constructed and operated.”
The plant is now under construction in Rialto. It was originally scheduled to open this year, but is now expected to come online in 2008.
“The industry never forgets a failure,” said Layne Baroldi of the Orange County Sanitation District.
The Orange County Sanitation District, the Sanitation Districts of Los Angeles County, and the cities of Riverside, San Bernardino and Rialto, have all signed contracts to send a collective 675 tons of sewage sludge a day to EnerTech’s plant. Missing from this list is the city of Los Angeles, which was courted by EnerTech but didn’t sign up.
EnerTech’s “SlurryCarb” process will subject sludge to extreme heat and pressure. Cellular structures rupture, carbon dioxide gas splits off, water is easily removed, and what’s left is essentially concentrated carbon. That stuff is dried and becomes what EnerTech calls “E-fuel,” which will be sold to power cement kilns in place of coal.
SlurryCarb, EnerTech says, is different from the process behind the Los Angeles fiasco, which is called “Carver-Greenfield.” Carver-Greenfield used oil to suspend solids as water is evaporated, which led to grave gumming up down the line; SlurryCarb does not. Carver-Greenfield used forced evaporation to remove water, which created yet other problems; SlurryCarb does not.
“Most of (Los Angeles’) problems do not apply to the SlurryCarb process because the two processes are designed to do completely different things,” says a 2005 report paid for by EnerTech, trying to assuage doubts.
Larry Stauch of Fullerton was surprised to hear that a project like this was going forward again. He worked for the Los Angeles County Sanitation Districts during the Carver-Greenfield troubles.
“The energy derived from human waste is small compared with the unbelievable amount of toxic emissions derived from the conversion process,” Stauch said in an e-mail. “This type of facility trades one form of pollution with another. The industrial waste present in our wastewater contains heavy metals such as cyanide, chromium, zinc, and they do not break down in any heat. They just become airborne.”
A permit has been issued for the Rialto plant by the South Coast Air Quality Management District, air emission controls have been built into the system, and heavy metals will not be released, said Baroldi of the Orange County Sanitation District.
“There are still unknowns about the SlurryCarb process,” EnerTech’s report says. “However … the Rialto project has a high likelihood of success.”
The Orange County Sanitation District agrees.
“Although the SlurryCarb process is a new technology, much of the equipment used in the process is common in the biosolids industry,” says a district report.
Even if the entire project went belly-up, venture capitalists and EnerTech would be left holding the bag, not taxpayers. “The only thing we would be out is time,” Baroldi said.
The problem of what to do with sewage sludge is getting more problematic – and expensive. It used to be applied to the ground as fertilizer – a cheap option at $42 a ton – but that is being outlawed as farm counties grow concerned about possible health effects. Turning the gunk into fuel with EnerTech will cost the Orange County Sanitation District $72.40 a ton.
“It’s cutting-edge, but we have to be innovative,” Baroldi said.
Contact the writer: tsforza@ocregister.com, or 714-796-6910.
