The call came in two minutes before 9 a.m. Sunday: there was a fire at the New Orleans Sewerage & Water Board's Carrollton power plant. As S&WB employees bee-lined to that campus, one of the four workers on site shut it down, depressurizing its miles of underground pipes for the next 15 minutes. For that length of time, more...
The call came in two minutes before 9 a.m. Sunday: there was a fire at the New Orleans Sewerage & Water Board's Carrollton power plant. As S&WB employees bee-lined to that campus, one of the four workers on site shut it down, depressurizing its miles of underground pipes for the next 15 minutes.
For that length of time, more than five times longer than the last pressure loss in October, the city's water system didn't have the pressure in its pipes to fully prevent anything bad from seeping in.
A fire had spewed through the vents of one of the plant's six boilers, charring part of its hull and damaging the paint and protective coating on nearby pipes, General Superintendent Joe Becker told the S&WB's operations committee Monday. Crews are still determining the extent of the damage.
A "glut" of natural gas flooding into the boiler set off the flare, which crews quickly extinguished. Becker said an air-induction fan, a device that regulates how much natural gas is burned to create the steam to power the plant's turbines, had failed. He compared the fire to what happens when a regulator valve fails on a gas stove - although on a much larger scale.
Investigators haven't nailed down all the details yet, but when they do, the board can expect a highly detailed report, Becker said.
Meanwhile, East Bank residents are advised to boil any water for a least a minute before drinking or cooking, a precaution against bacteria and other contaminants that may have seeped into water pipes during Sunday morning's low-pressure period. The S&WB said it is safe to do laundry, clean or run a dishwasher, as long as it has a sanitizing cycle. Healthy people can bathe, but it's advisable to keep their eyes and mouths shut. Residents with compromised immune systems or open wounds should avoid the shower for now.
Algiers, which has a separate water purification plant across the Mississippi River, was not affected.
The fire occurred in boiler No. 5, one of six that run any combination of the power plant's four turbines. In turn, the turbines, built in 1947, don't have an automated safety shutoff. In an emergency, a S&WB employee has to pull the switch.
Once that happened Sunday morning, the boil-water advisory was called within the hour as S&WB staff touched based with the state Department of Health and Hospitals, which regulates the safety of public water supplies. S&WB crews fanned out across the city to collect samples from specially designated sites along the S&WB's miles of pipelines. The samples are then monitored for at least 24 hours to see if anything starts growing - a gestation period that demands boil-water advisories stay in place for more than a day.
S&WB staff appeared cautiously confident Monday that no contaminants had infected the water. Becker and Executive Director Marcia St. Martin said residual chlorine throughout the system would further help prevent any contaminants from gaining a foothold in the water supply.
The S&WB power plant produces an uncommon frequency of electricity known as 25-Hertz, also called 25-cycle, that drives the motors that run most of the city's drainage, sewerage and drinking water systems. It powers giant pumps that suck raw water from the Mississippi River and smaller pumps that send purified water into the underground pipe network. The city's two water purification plants run on 60-cycle power purchased from Entergy.
The power plant generates electricity by running tap water through enormous boilers, which create steam to run four turbines that produce 25-cycle power. Natural gas purchased from Entergy is used to start boilers and turbines, which run singly or in tandem, depending on how much power the system needs.
Once the equipment is up and running, it relies on self-generated steam and a series of natural gas feeds to stay online.
The S&WB has eight pumps located at three outflow stations on the South Claiborne Avenue campus to send purified drinking water out to customers. The pumps maintain water pressure at about 65 pounds per square inch, a level that keeps potentially sickening bacteria from infiltrating pipes; when pressure drops below 15 psi, health officials advise residents to boil water before using it to drink, cook or bathe.
Besides pressure gauges at the Carrollton plant, the S&WB has backups at five remote locations to monitor any dramatic drops in pressure throughout the system.
The S&WB's aging power plant has seen better days. Becker said the S&WB has issued five boil-water advisories or orders since floodwaters inundated the power plant after Hurricane Katrina. Most recently, a 41-hour advisory occurred in November 2010 and another 25-hour advisory in October. Both were linked to boiler problems at the plant.
The S&WB caught flack during in October because it took several hours to warn the public about the pressure drop. Water board and state officials eventually made the call out of an "abundance of caution" even though pressure had only slacked for about three minutes. Nobody reported any sickness outbreaks from the incident, but the warning didn't come until after most residents had bathed, brushed their teeth, eaten breakfast and headed to work.
Board member Flo Schorenstein chided the S&WB staff Monday for not doing a better job to warn board members of Sunday's advisory. She said she learned about it from watching television while fielding calls from concerned residents.
"In a way, I was embarrassed," she said. "I didn't know anything more about the situation I happened to see running across the screen like everybody else."
Becker apologized to Schornstein, and Dep. Executive Director Bob Miller said that one of the S&WB's top goals this year was to improve communications over a bevy of different digital devices.
Built in 1903, the power plant ran considerably well until Katrina. To drain the city in 2005, the S&WB used equipment that was never meant to handle saltwater. The damage was astronomical, Becker said.
Debate is raging about how to fix the plant. During discussions that led to major rate hikes last year for water and sewer services to businesses and residences, a task force of outside engineers and consultants determined that the S&WB should focus on converting the power plant fully to self-generated 60-cycle power. The current gas-to-steam system has too many opportunities for failure, task force spokesman Jeff Thomas said Monday.
"At any point along the way there, something can go wrong," he said, "which it has."
You can read the task force's report here.
The task force, led by former S&WB member Gary Solomon, recommends that the station's four turbines be fueled directly by heat from natural gas, removing steam from the system. Older pump stations should be outfitted with converters that switch 60-cycle electricity to 25-cycle, Thomas said.
That conversion isn't without its downsides, however. Supporters of 25-cycle energy say it causes less wear and tear on the plant's equipment because turbines that use it rotate at slower speeds. Becker also said that the full conversion to 60-cycle would require all new wiring and new motors at the city's pump stations - many of which are too small to accommodate modern equipment. He put the full upgrade at a whopping $1 billion.
Becker said that repair plans do not include converting the plant's four turbines to a more modern form of electricity.
The power plant's turbines and boilers are in various states of disrepair, and after Sunday's fire, only two boilers are online, Becker said. The U.S. Army Corps of Engineers are storm-proofing two others, one of which can be turned on in a pinch if necessary. And a sixth boiler was already out of commission for repairs when No. 5 went down Sunday.
On a day with little chance of rain and street flooding, Becker said one boiler can produce enough steam to create enough 25-cycle power to run the system.
Of the plant's four turbines, No. 4 has been out of commission for about six months, with another seven or eight months left in its federally subsidized overhaul. FEMA and the S&WB have poured about $12.5 million into repairing it, Becker said.
"When that turbine is online it will basically be a new turbine," he said.
The S&WB recently received a $141 million federal hazard mitigation grant - $100 million of which will be poured into the power plant's repairs. The S&WB picked the Colorado engineering firm CH2M Hill last month to lead the design of the renovations. The first $6.6 million of that federal money will go toward fixing the turbines, Becker said.
The S&WB is also exploring other options. Becker said they are drafting a proposal to connect a new 15-megawatt, 60-cycle power plant that the corps is building on the Carollton site. And St. Martin said plans are in the works to propose building four, 200-foot-tall water towers in the city that, in an emergency, can be opened to flood water pipes and return pressure in an instant. New Orleans has one tower on each side of the Mississippi River, but that's woefully less than many cities its size, she said.
While the repairs should return the power plant to its past reliable glory, the next few years will likely be touch and go.
"Historically (a boil-water advisory has) been very, very rare," Becker said. "After Katrina, it's been unfortunately not as rare as we would like. But with the repair work that is ongoing, along with the funding that we have and the repair work that we're going to be able to do over the next two or three years, we're very confident it will become very rare again. Unfortunately, we're going to have a couple years here where we're not going to have a whole lot of redundancy in our system and if something doesn't work, then we're going to have to be able to react quickly."