Welcome to the future. One of the results of all the fighting that goes on
over water, such as we read about last week, is that new ways to use the
water we have will be further investigated. That's exactly what we have in
this article. It exemplifies the efforts being made for water reuse. And
what will is the biggest obstacle by far in being able to engage in water
reuse? Will it be cost, or some extreme technological hurdle? No, not at
all. The biggest hurdle by far will be public perception and the wall of
mistrust and misunderstanding that the average person has about the
process. Think about it - the Orange County Water District is making some
incredibly pure water here, and then pumping it back into the ground, not
for purification reasons, not just for storage reasons, but because of
public perception that this will somehow make the water safer. The same
hurdles would be faced anywhere, including here in the Midwest, where we
effectively have engaged in water reuse for a very long time - treated
water from sewage treatment plants goes into the river and then is sucked
right back in to the intakes of drinking water treatment plants just
downstream. But very few people would be comfortable with taking that
water from the sewage treatment plant and pumping it directly to the
drinking water treatment plant. Not yet, anyway; but as water supplies
continue to shrink and demand continues to rise, that will be a part of
where our future lies.
The New York Times
November 27, 2007
From Sewage, Added Water for Drinking
By RANDAL C. ARCHIBOLD
FOUNTAIN VALLEY, Calif. — It used to be so final: flush the toilet, and
waste be gone.
But on Nov. 30, for millions of people here in Orange County, pulling the
lever will be the start of a long, intense process to purify the sewage
into drinking water — after a hard scrubbing with filters, screens,
chemicals and ultraviolet light and the passage of time underground.
On that Friday, the Orange County Water District will turn on what industry
experts say is the world’s largest plant devoted to purifying sewer water
to increase drinking water supplies. They and others hope it serves as a
model for authorities worldwide facing persistent drought, predicted water
shortages and projected growth.
The process, called by proponents “indirect potable water reuse” and
“toilet to tap” by the wary, is getting a close look in several cities.
The San Diego City Council approved a pilot plan in October to bolster a
drinking water reservoir with recycled sewer water. The mayor vetoed the
proposal as costly and unlikely to win public acceptance, but the Council
will consider overriding it in early December.
Water officials in the San Jose area announced a study of the issue in
September, water managers in South Florida approved a plan in November
calling for abundant use of recycled wastewater in the coming years in part
to help restock drinking water supplies, and planners in Texas are giving
it serious consideration.
“These types of projects you will see springing up all over the place where
there are severe water shortages,” said Michael R. Markus, the general
manager of the Orange County district, whose plant, which will process 70
million gallons a day, has already been visited by water managers from
across the globe.
The finished product, which district managers say exceeds drinking water
standards, will not flow directly into kitchen and bathroom taps; state
regulations forbid that.
Instead it will be injected underground, with half of it helping to form a
barrier against seawater intruding on groundwater sources and the other
half gradually filtering into aquifers that supply 2.3 million people,
about three-quarters of the county. The recycling project will produce much
more potable water and at a higher quality than did the mid-1970s-era plant
it replaces.
The Groundwater Replenishment System, as the $481 million plant here is
known, is a labyrinth of tubing and tanks that sucks in treated sewer water
the color of dark beer from a sanitation plant next door, and first runs it
through microfilters to remove solids. The water then undergoes reverse
osmosis, forcing it through thin, porous membranes at high pressure, before
it is further cleansed with peroxide and ultraviolet light to break down
any remaining pharmaceuticals and carcinogens.
The result, Mr. Markus said, “is as pure as distilled water” and about the
same cost as buying water from wholesalers.
Recycled water, also called reclaimed or gray water, has been used for
decades in agriculture, landscaping and by industrial plants.
And for years, treated sewage, known as effluent, has been discharged into
oceans and rivers, including the Mississippi and the Colorado, which supply
drinking water for millions.
But only about a dozen water agencies in the United States, and several
more abroad, recycle treated sewage to replenish drinking water supplies,
though none here steer the water directly into household taps. They
typically spray or inject the water into the ground and allow it to
percolate down to aquifers.
Namibia’s capital, Windhoek, among the most arid places in Africa, is
believed to be the only place in the world that practices “direct potable
reuse” on a large-scale, with recycled water going directly into the tap
water distribution system, said James Crook, a water industry consultant
who has studied the issue.
The projects are costly and often face health concerns from opponents.
Such was the case on Nov. 6 in Tucson, where a wide-ranging ballot measure
that would have barred the city from using purified water in drinking water
supplies failed overwhelmingly. The water department there said it had no
such plans but the idea has been discussed in the past.
John Kromko, a former Arizona state legislator who advocated for the
prohibition, said he was skeptical about claims that the recycling process
cleanses all contaminants from the water and he suggested that Tucson limit
growth rather than find new ways to feed it.
“We really don’t know how safe it is,” he said. “And if we controlled
growth we would never have to worry about drinking it.”
Mayor Jerry Sanders of San Diego, in vetoing the City Council plan there,
said it “is not a silver bullet for the region’s water needs” and the
public has never taken to the idea in the 15 years it has been discussed
off and on.
Although originally estimated at $10 million for the pilot study in San
Diego, water department officials said the figure would be refined, and the
total cost of the project might be hundreds of millions of dollars.
Although the Council wants to offset the cost with government grants and
other sources, Mr. Sanders predicted it would add to already escalating
water bills.
“It is one of the most expensive kinds of water you can create,” said Fred
Sainz, a spokesman for the mayor. “It is a large investment for a very
small return.”
San Diego, which imports about 85 percent of its water because of a lack of
aquifers, asked residents this year to curtail water use.
Here in Orange County, the project, a collaboration between the water and
sanitation districts, has not faced serious opposition, in part because of
a public awareness and marketing campaign.
Early on, officials secured the backing of environmental groups, elected
leaders and civic groups, helped in part by the fact the project eliminated
the need for the sanitation district to build a new pipe spewing effluent
into the ocean.
Orange County began purifying sewer water in 1976 with its Water Factory 21
, which dispensed the cleansed water into the ground to protect groundwater
from encroaching seawater.
That plant has been replaced by the new one, with more advanced technology,
and is intended to cope with not only current water needs but also
expectations that the county’s population will grow by 500,000 by 2020.
Still, said Stephen Coonan, a water industry consultant in Texas, such
projects proceed slowly.
“Nobody is jumping out to do it,” he said. “They want to make sure the
science is where it should be. I think the public is accepting we are
investigating it.”