Subject: sewage plant question
Date: Dec 25 14:33:04 2002
From: birders.2341 at attbi.com - birders.2341 at attbi.com


Gary,
?
I am an electrical engineer that spent 13 years designing electrical and
control systems for WWTP?s.? I'm also a birder. I?ve not been working
in waste water since 1994.? Nevertheless I learned a few things
regarding waste water treatment during that period.
?
Generally, lagoon treatment systems are used in relatively small
communities, since the land required for lagoon treatment is relatively
large compared to other treatment systems.? This is because the
biological processes used for treatment are generally not extensively
augmented by mechanical equipment.? Accordingly the capital costs are
considerably lower than other systems of treatment.? In larger
communities the waste water flows naturally are considerably higher and
land is more valuable.? The biological processes are necessarily
augmented with more mechanical equipment, to speed up the treatment
process.? Due to the higher waste water loads and more concentrated
treatment the odors are considerably greater. Also the plants are more
likely to be located in populated areas, which make them more
objectionable to neighbors.? To control these odors, additional
processes must be added to treat the odors.? These processes and the
necessity of alleviating neighborhood complaints require that the ponds
be covered and screened.? The net result of the different biological
processes used and the use of odor control equipment is that the
treatment plants in larger communities tend to be covered and not
attractive to birds.? Birds are attracted to lagoon treatment ponds
because the ponds are nutrient rich and offer good sources of food.?
Also they tend to be sheltered from the worst weather.
?
As far as the municipalities considering birders, I doubt if birding
would be a major factor in making a design decision regarding a
treatment system, since of far more importance are such things as
capital costs, operational costs and technical feasibility when a
treatment process is selected.? That being said I have found that most
municipalities welcome birders to the lagoon treatment plants. Also in
many cases the municipal agencies go to great lengths to be
environmentally friendly. For example, I once worked on a treatment
plant where a creek had to be relocated. In that case the creek was
filled with trash, etc. The creek was rehabilitated and relocated into
a channel that approximated a natural stream bed. Salmon runs were
reintroduced into the creek.
?
I hope this more or less answers your questions.? As I said I?m an
electrical engineer and not a sanitary engineer.? However, I believe
that the foregoing is generally correct.
?
Tom Merritt
Email: birders.2341 at attbi.com
Seattle, WA
?
-----Original Message-----
From: Gary Bletsch [mailto:garybletsch at yahoo.com]
Sent: Monday, December 23, 2002 21:26
To: tweeters at u.washington.edu
Subject: sewage plant question
?
Dear Tweeters,
I don't know much about sewage treatment. I do know there are often
great numbers and variety of birds on sewage treatment ponds.
I?have often?wondered whether newer facilities tend to favor birds or
not. Some facilities are roofed over, and offer nothing to birds. These
facilities seem modern to me, but I don't know. Are they still building
sewage ponds today, or must it all go underneath a cover??
One question I have often asked myself--has any municipality ever
considered birds in the decision-making process connected with
construction or renovation of such facilities? It? is not inconceivable
that a good sewage plant could bring birders' tourist dollars to local
businesses.
On a non-sewage note, I found two Savannah Sparrows on Cockreham Island
today, loosely associating with six Western Meadowlarks.
Good birding,
Gary Bletsch
near Lyman, WA
garybletsch at yahoo.com
?
?

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