John Poppe of West Sound Utility District tells me that his
phone has been ringing off the hook over biosolids — processed
sewage sludge — that will soon be offered to anyone free of
charge.
I announced in
Monday’s Kitsap Sun that the utility district had received a
Class A certification for its “pasteurized” biosolids. The
certification allows the material to be used even on vegetable
gardens, because the certified treatment process is designed to
destroy all measurable pathogens.
Biosolids have been proven to be a rich soil amendment, but
their use remains controversial. I consider the controversy to be
in the realm of debates where the question is, “How safe is
safe?”
It seems as if it has taken forever for someone in Kitsap County
to put treated sewage to beneficial use, but a demonstration
project on Retsil Road in South Kitsap is just around the corner.
Check out my story in
Saturday’s Kitsap Sun.
Darren Noon of Pape and
Sons Construction Co. welds a section of "purple pipe" along Retsil
Road in South Kitsap, the first reclaimed water project in Kitsap
County.
Kitsap Sun photo by Meegan M. Reid
Local water experts were contemplating uses for highly treated
wastewater even before “low-impact development” became a common
phrase for infiltrating stormwater into the ground.
LID has caught on fairly quickly as a method of keeping polluted
stormwater from reaching our streams and Puget Sound. The concept
got an extra push from new stormwater regulations, which have
greatly increased the cost of conventional pipe-and-pond methods of
stormwater management.
The less-touted benefit of LID is groundwater recharge, which
boosts our long-range water supply.
Kitsap County’s Watershed Management Plan (PDF 147 kb),
developed in 2005, estimated that Kitsap County’s sewage treatment
plants release 8 million gallons of treated water into Puget Sound
each day. That’s enough to increase the base flow of 10 streams by
10 cubic feet per second, raise aquifer levels throughout the
county or launch a new industry without touching our drinking water
supplies.
“The most significant barriers to recycling wastewater are the
cost of infrastructure and additional treatment, as well as public
perception,” the report states. “Elected officials in WRIA 15 (the
Kitsap Peninsula) have expressed support for public education about
reclaimed water.”
The report mentions that highly treated effluent from the
Central Kitsap Wastewater Treatment Plant near Brownsville could be
used to supplement streamflows in nearby Steele Creek. But more
recently Kitsap County and Silverdale Water District have begun
working together on a plan to pipe the water into the heart of
Silverdale, where it can be used to water ballfields and
landscaping.
That’s also the initial plan put forth by West Sound Utility
District, as I mentioned in Saturday’s story. Using wastewater for
irrigation cuts down on peak demand, which is what drives water
utilities to drill new wells. Needless to say, drilling deep wells
comes at a tremendous expense — an expense that grows greater as
Kitsap County approaches the limits of its groundwater supplies in
some locations.
To many people, using reclaimed wastewater seems like a novel
idea, especially in an region known for its rain. People remain
squeamish about getting anywhere near sewage water, even if it is
treated. But I don’t believe it will take long for people to accept
the idea of using treated wastewater for irrigation, once they
realize it is treated to basically the same level as drinking
water.
On the other hand, drinking treated effluent becomes another
issue, even though it has been done indirectly for years in many
places. If you live in a town on the Mississippi River, your local
utility may be drawing water out of the river for your consumption
just downstream of where a sewage treatment plant is dumping its
effluent.
There are several other places where reclaimed water is mixed
with freshwater, such as in a reservoir, then drawn back out for
drinking. Ironically, putting the wastewater into a reservoir makes
it seem more palatable, even though it probably was cleaner before.
Treating the water in the reservoir is essentially treating the
wastewater again — although water is just water in the end.
A community in Texas made news across the country last week,
when reporter Angela Brown of the
Associated Press wrote about a new $13-million
water-reclamation plant to turn effluent into drinking water, the
first to be built in that state. Really, it is nothing new, as
Angela herself points out.
What I have not found anywhere so far is a direct use of
reclaimed water. That’s what you would get by pumping the highly
treated wastewater directly into a municipal water system’s piping
network. From a health standpoint, there would be nothing wrong
with that, provided the water could be shut off in the event of a
problem at the treatment plant. No doubt this kind of direct use
will be a little harder to get used to, even in areas where water
is scarce.
Alix Spiegel of National Public Radio does a nice job analyzing
the psychology behind the aversion to using treated wastewater and
why people are more accepting of indirect use. Read or listen to
“Why Cleaned Wastewater Stays Dirty In Our Minds .”
David Parry, Northwest regional president for Camp Dresser &
McKee, an engineering and consulting firm, makes a good case for
turning sewer gas into energy.
As he explained to commissioners and staff for West Sound
Utility District and Silverdale Water District, you need to remove
carbon dioxide and impurities from biogas to get a high-quality
methane, which is essentially natural gas that can heat buildings,
run cars or generate electricity. Read more details in my story
published in
Sunday’s Kitsap Sun. Responding to a question, Parry did a
quick back-of-the-envelope calculation about the costs and
potential of converting biogas generated at West Sound’s
sewage-treatment plant near Retsil. Conversion equipment would cost
roughly $500,000, he said, and it would produce an amount of
natural gas equivalent to about 100 gallons of gasoline a day.
After hearing his talk, it makes sense to me that
sewage-treatment plant owners and operators should at least
consider some kind of system for using the energy that would
otherwise go to waste.