 |
| Craig Schrader (left)
and Linda Atkins, Jefferson County Health and Human
Services Department, collect samples from a septic
system demonstration project site to test its ability
to remove nitrogen. (November 2005) /
Terry Hull, Action Team |
Not only did the septic drain field
at John and Carrin Sheridan’s home on Highway 106
back up and overflow right in their own front yard, but
their neighbor’s sewage drained there too. Down
the road, under orders from the Mason County Health Department,
a duplex sat unoccupied because its septic system had
also failed.
Now those three properties are connected
through a small community “cluster” system,
which treats sewage at each of the three sites and then
directs the clear effluent from each home to a new, shared
drip-irrigation drain field on the Sheridan’s property.
The innovative drain field, located as far from the shoreline
as possible, uses native plants to absorb nitrogen before
it can reach the canal.
“A lot of people have a stake in
the success of this new system,” John Sheridan said. “I’m
pretty comfortable with what this can do for the canal.
And it’s so simple, it’s not even funny.”
New hope for tired septic systems
In 2004, the Action Team directed nearly $800,000 in state and federal
funding for 14 pilot projects such as the one on the Sheridan’s
property to correct the low levels of dissolved oxygen in Hood Canal.
Many factors contribute to the canal’s “dead zone,” including
excess nitrogen leaching from septic systems.
Several of these projects will improve
the way onsite sewage systems deal with nitrogen produced
by traditional septic systems. Contractors have finished
construction on a new system and also on retrofits for
existing systems along Hood Canal’s south shore that
demonstrate how new technologies can remove excess nitrogen,
thus reducing their contribution to the canal’s low
dissolved oxygen problem.
Retrofit goes aerobic
Older septic systems from three waterfront homes west of Twanoh will now
do a better job of keeping nitrogen out of Hood Canal. A relatively simple
upgrade creates a complex aerobic-anaerobic process, with the ultimate
goal of reducing the amount of nitrogen in the effluent that leaves the
treatment tank. The aerated waste, now clearer and containing less nitrogen,
is disinfected using ultraviolet light as it flows to the homes’ drain
fields.
Find more examples of progress to correct
low dissolved oxygen in Hood Canal at www.psat.wa.gov/hoodcanal.
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