David E. Ross wrote:
songbird wrote:
David E. Ross wrote:
...
Where I live, sewage (not merely gray water) is treated at a plant that
is mostly gravity fed. The input is from both residential and
commercial sources. At the plant, liquids are separated from solids.

arg! precisely the problem which should be avoided.
combined residential and commercial sewage... always a
bad idea as it gives the businesses a free pass to let
trace contaminants and odd chemicals off site without
compensation to the treatment facility to manage the
results and it then also contaminates all the wastes so
that they can't be reused. which is why later on you
mention that they can't be reused in veggie gardens
without restrictions.

No one want to pay the costs of duplicate sewage plants and sewer lines
that would be required to treat residential and commercial sewage
separately.

of course! but in the end it's much better to
make incentives for businesses to clean up their
processes so that things aren't contaminated to
begin with.


Liquids are "tertiary" treated and then pumped back uphill to irrigate
parks, school playfields, greenbelts, and two golf courses. So far, the
use of such reclaimed water is not covered by drought-induced
restrictions. Furthermore, the ability to use this on school playfields
means it is biologically safe. However, the reclaimed water contains
too much dissolved minerals for domestic use. Because of that,
individual homeowners are not allowed to tap that source; there is a
concern that amateur plumbers -- the homeowners -- might accidentally
cross-connect a reclaimed water line with a potable domestic water line.
This concern about contaminating potable water with reclaimed water
also means that the mains carrying reclaimed water operate at a lower
pressure than potable mains.

The solids are composted to the extent that they too are biologically
safe. Dried, this compost is free to anyone who brings a container --
including a truck -- to the composting site. Again, the presence of
dissolved minerals (possibly heavy metals from commercial sources of
sewage) is a concern. Thus, users of the compost are advised to place
only a small amount in beds containing edible plants such as vegetables
and fruit trees. Larger amounts can be used on ornamental plants.

yeah, but once it's applied then it's basically
spreading a contamination issue around. i wonder
what percentage of it is actually used instead of
being landfilled (or in some cases incinerated which
can spread the heavy metals around even more).

None of the compost is burned or transferred to landfills. It is free
for the taking, and many landscape contractors take large amounts.

interesting!


All this is a result of political pressure from homeowners downstream
from the sewage plant in Malibu. They wanted to restrict the plant's
operation because they feared they too would be required to abandon
their septic tanks and instead connect to sewer lines, thus opening
Malibu to increased development and population density. After the
sewage plant succeeded in developing a market for reclaimed water,
however, those same NIMBY homeowners changed their pressure to require
some of the reclaimed water to flow down Malibu Creek to maintain
riparian wildlife, including fish that had not been in the creek for
decades.

if the water is there and the stream benefits why
would this be bad? it returns a previously damaged
river to some forms of life and gives fish habitat
that they'd lost.

Much of the cost of treating reclaimed water is paid by the users -- the
parks, golf courses, home-owner association greenbelts. The price of
reclaimed water is about 75% of the cost of potable water, and there are
no drought-imposed restrictions on how much a customer may use. During
the current drought, the demand for reclaimed water approximately equals
the supply. The demand to pour that water into Malibu Creek creates a
shortfall in the supply.

all of the water is then being used and is in
some manner contributing to ground water recharging
and stream flows so to me that's much better than
just sending it out to sea.

i guess i'd rather have a stream flowing than not
even if it means some costs are a little higher.


The natural flow of water in Malibu Creek above the sewage plant is
contaminated by wildlife in the Santa Monica Mountains National
Recreation Area.

i wouldn't call it contamination but that's just me.
animals poop/pee. just if it is safe or not for people
to swim in it or fish it or ...

In those terms, it is safe. That is why making the flow even cleaner
downstream from the sewage plant than it is upstream is so outrageous.

my guess is that they really can't release water from
any point in the process earlier without causing an
environmental problem. many of the more modern treatment
plants have things in place to recapture the various
chemicals/additives used and the very last part of the
water treatment is an UV flash to kill off any
remaining bacteria/virii. skipping that would be a
bad idea, especially in a warm climate.


Now, the Malibu homeowners have convinced California
state authorities to mandate that the flow of water in the creek below
the sewage plant to be cleaner than the natural flow above the plant.

with modern wastewater treatment plants this is actually
not uncommon at all. the troubles from treatment plants
and sewage is often storm water overflows driven by combined
waste and storm water drains. in many cities here they are
gradually removing such combined systems to give the rivers
a better chance of not being contaminated by sewage overflows.
and it's working. things are gradually improving. but it's
taking time and a lot of money. money which would not be
required to be spent had the systems been dry compost forms
instead. ah well...

Throughout southern California, storm drains and sewage mains are quite
separate. However, the "gunk" rinsed by rain into storm drains can
cause significant pollution at beaches after a major rain storm.

yep. cars are not designed to be clean. however,
horses weren't all that good either...


I pay over $500 a year in sewage fees for only my wife and me. There is
no winning, only different ways of losing.

that is water and sewage cost or just sewage/disposal
cost?

even if we include the cost of the whole plumbing system
here and septic field we could get it to around $300/yr but
that's because we've been here almost 20 years now (wow how
time has gone by!). it doesn't cost that much to have the
tank pumped and taken to the sewage treatment plant. i still
don't like it. a dry system would be much cheaper. sawdust
can be had by the truckload here for not much, leaves and
dirt are free. the gardens would be much happier too.

That $500+ is for sewage only. Twice each year, I pay half of it with
my property tax bill; but it is a service charge and not a tax. I pay
my water bill monthly. Water is also expensive. Almost half of my
total utility costs -- water, electricity, phone, and natural gas -- is
for my water bill.

ouch! but it makes sense to me that in an arid
climate that water/sewage would be more expensive to
treat. out there with the somewhat hilly terrian
that isn't all that stable i think maintenance would
also be higher.


songbird