A cleaner solution to sewage
Paul Clinton
Disinfecting Orange County’s sewage with chlorine may be new to
residents here, but the process dates back to the 1850s and has been
widely used by sanitary districts in other pockets of the country.
Last week, the Orange County Sanitation District joined many of
its peers in the waste treatment business by beginning a process in
which the sewage is soaked with industrial-strength bleach. After a
dechlorination chemical removes the bleach, the waste is released via
an outfall pipe on the ocean floor 4 1/2 miles out to sea.
The bleach, about three times more potent than the everyday
household variety, kills off much of the bacteria present in the
sewage, which is also treated with other methods.
“The fact of the matter is the chlorination-dechlorination process
will remove up to 90% of the viruses,” said Bob Ooten, the district’s
director of maintenance and operations. “We’re meeting our
disinfection goals.”
The sanitation district uses between 18,000 and 20,000 gallons of
bleach per day on the 234-million gallons of waste water released
into the ocean each day. It’s costing the agency about $8 million per
year to purchase the needed chemicals.
Sanitation district leaders asked regional water-quality
regulators in February if they could begin the disinfection as a way
of clearing the outfall pipe in the ongoing investigation into what’s
causing bacteria outbreaks along Huntington Beach and Newport Beach
shorelines.
A $5.1-million water quality study, funded by the district,
concluded that a multitude of onshore causes -- including leaky
sewage pipes, urban runoff and bird waste in the Santa Ana River --
could also be contributing to the problem.
“There is some evidence that the plume is coming to shore,” said
Key Tyson, an environmental scientist with the Santa Ana Regional
Water Quality Control Board. “[Disinfection] is providing further
protection to public health.”
On July 17, the district’s board approved a stepped-up treatment
method for the sewage. The decision came two days after the regional
board ordered the agency to begin chlorination by Aug. 12.
Local leaders aren’t enthused about chlorination, but say it could
be used as a stop-gap method until greater treatment of the discharge
can begin.
“It’s not the ideal situation,” Mayor Debbie Cook said. “If that’s
what we have to do, that’s what we have to do ... We would prefer to
have no bacteria or viruses in our outfall pipe, but that’s just not
the case right now.”
QUESTIONS EMERGE
Environmentalists have raised some questions about the
effectiveness of bleach in combating viruses in sewage.
Jack Skinner, an environmentalist and physician in Newport Beach,
said he worries that chlorination will give swimmers a false idea
about the cleanliness of the area’s beaches.
“If it hasn’t been treated to full [treatment levels], it takes
much more chlorine to kill off the bacteria and viruses,” Skinner
said. “You’ll get a false assurance. There’s not enough chlorine
added to kill off the viruses among swimmers.”
Other environmentalists say the process creates potentially
harmful chemical byproducts that could damage fish or plant life in
the sea. Doug Korthoff, one of the founders of the activist Ocean
Outfall Group, said the process creates “bad compounds.”
Officials defend the method, saying those byproducts don’t exist
in high enough levels to be harmful.
WIDELY USED
Orange County sanitation officials have begun chlorine treatment,
joining the nearly 400 other agencies that use the method statewide.
Agencies in San Francisco, Los Angeles, Lake Arrowhead, South
Laguna, Mendocino and other areas use it.
The Sanitation Districts of Los Angeles County, a joint-powers
agency that runs 11 sewage treatment and water reclamation plants,
has used chlorination on their waste since the 1950s, spokesman Joe
Haworth said.
“It’s a very effective tool for knocking the numbers of bacteria
down geometrically,” Haworth said. “That’s why you chlorinate your
pool.”
The Los Angeles agency uses a somewhat different method to
chlorinate its sewage, mixing the chlorine with lime, the same
chemical used to decontaminate drinking water in the trenches of
World War I.
Haworth said the agency spends about $2.5 million per year on the
chlorine, lime and bi-sulfite used to remove the chlorine before it
is released into the ocean.
REACHING INTO HISTORY
Water agencies have been chlorinating drinking water for more than
150 years. Back in 1850, John Snow first used the chemical to
disinfect the water supply in London after a cholera outbreak.
Regular chlorination of drinking water didn’t begin until 1897, also
in London. In this country, chlorination began for the first time in
Jersey City in 1908.
The more widespread adoption of the treatment method resulted in
one of the most important public health advances in this country’s
history, as doctors watched water-born illnesses like cholera,
typhoid, dysentery and hepatitis A virtually disappear from their
patients.
Today, local water districts like Mesa Consolidated still employ
the method.
“In order to avoid any development of bacteria, a very low level
of chlorine keeps [the water] from going bad,” said Diana Leach,
Mesa’s general manager.
Mesa uses small doses of chlorine, because the water it pulls from
the ground water wells is clear.
Using chlorine on sewage is another matter, so Orange County
Sanitation District officials use much higher doses of the bleach on
its sewage.
* PAUL CLINTON covers the environment and politics for Times
Community News. He may be reached at (949) 764-4330 or by e-mail at
paul.clinton@latimes.com.
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