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$ - Keep Your Septic System Sweet! 2/14/08 (Printer-friendly
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How
can you keep your septic system working well?
Conserve water. Send the septic system
less than 50 gallons per bedroom per day,
and under 10 gallons per bedroom per hour: Spread out baths, showers, laundry,
etc. (8-min shower@2.5 gallons per minute=20gal, bath=washer=25-40gal,
flush=1-7gal).
Drain hot tubs[3] &
water beds elsewhere or over several days. Water softener salts may
or may not hurt;
minimize water with flow-based softener, not timer-based. Electronic softener
may work.[5]
Reverse osmosis purifiers create 1-9 times as much waste water as the
2-15 gallons of clean water they deliver per day.[6]
Drainfield handles moderate flows forever
(Long Term Acceptance Rate, LTAR). Wash water (graywater) has lots of bacteria
& soap; it needs to go to septic or other treatment.[8]
Don't flush what kills
bacteria:[9]
Paint, chemicals, gas, pesticide, medicine,
drain cleaner (11grams at a time ok), bleach (1.8gal ok).
Don't flush what bacteria
can't eat:
Oil, coffee grounds, plastic (e.g. floss, diapers), clay-based cat litter
(corn-based OK), cigarette butts, paper except toilet paper.
These accumulate & must be pumped out. Powdered detergents often include
clays (zeolite, montmorillonite) which accumulate or clog soil.
Hair flows through & clogs soil. Septic additives don't help
& may hurt.
Install a water meter to measure water use.
(Biggest leaks can be toilets: Put food color in tank; does it appear in bowl?)
Find a pumper who will do the following
(yellow pages under Septic; they'll find tank electronically if needed): Measure
sludge & floating layers before pumping.
After pumping, hose walls & look for leaks.[15]
Replace concrete outflow baffle
(can corrode & let oil through) with PVC tee. Add a filter
where water leaves tank.
Have distribution box checked; it can tip or corrode. Have tank pumped every
3-5 years. Pump annually if you use a garbage disposal. While pumping,
water flowing into tank from drainfield means field is waterlogged. Water
trickling from house means a leak, or blockage.
What
are alternative costs if your septic system stops working?
The symptom of a problem is
water appearing at the lowest overflow point: a plumbing fixture or wet ground,
not always odor.[17]
Approximate cost
FREE Conserve water as
drastically as possible.
Better than free: saves $$. Read water meter daily or weekly.
$0-500 Make sure storm water
doesn't drain into septic system or onto drainfield.[19]
$0-1,500 Go away for as many
weeks as you can (vacation, friends, rent a house).
$1,500 Add pump or siphon[20]
to send liquid from tank intermittently. This "pressure dosing" can
be as good as alternating drainfields.
$1,500 Dig & divert
flows to a temporary drain line if you have a little space.
Chamber may be better than gravel.
$1,500 Add a 2nd
septic tank or replace with a 2-chamber model.
Add a filter.
$1,500 Replace any septic
tank that lets water leak in.
$2,500 Dig & divert flow
to another drainfield if you have enough space.
$3,000 -9,000 Connect septic
outflow to community drainfield.
$10,000 Replace your septic
system with a home aerobic unit or other treatment.
$10,000 Replace soil &
drainpipes. (Hydrogen peroxide does not fix drainfield.[27])
$25,000 Connect to public
sewer & pay monthly bills.
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How do septic systems
work?
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What can go wrong at each
step?
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1
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Water & waste drain to
a septic tank (1,000-2,000 gallons, concrete, fiberglass or polyethylene).
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Internal baffles can
corrode, break, or leak, so oil & paper wash into drainfield & clog
it. Septic gas is dangerous; stay out & don't smoke near it.
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2
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Solids settle & light
things like oil & paper float in the tank. Many ingredients are slowly
broken down by bacteria.
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(a) Sending water too fast
doesn't leave liquid in tank long enough for solids & oils to separate
out, & may exceed percolation rate of soil.
(b) Omitting pumpouts lets
solids or oils build up until they can wash out to drainfield. See step 5.
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3
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Liquid flows out to a
distribution box and then to 300-500 feet of perforated pipes in gravel beds
in the soil (drainfield).[29]
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Trees & bushes within
20 feet of
drain lines can clog pipes with roots. (Remote camera can inspect pipes.)
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4
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Liquid spreads through gravel
& is then filtered by soil & treated by bacteria.[31]
Good bacteria digest nutrients & pathogens in the liquid & multiply,
forming a valuable biological mat in pores of soil & gravel.
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(a) Driving on drainfield
compresses soil: water can't flow; bacteria can't grow.
(b) If water in drainfield
(rain plus septic system) exceeds percolation rate of soil, water will back
up in pipes or in soil.
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5
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Bacteria die after a normal
lifespan, re-opening pores, and are constantly replaced.
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Too many nutrients (from problem
2) make biomat grow faster than it dies; it becomes nearly impermeable, and
water rises to surface or backs up into home. (Soil auger can take sample to
inspect biomat.
Infrared photos or sampling devices can measure flows & pollution.)
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6
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Clean liquid flows into
groundwater, including any caverns or channels below ground
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If pipes were installed too
close above rocks, then unfiltered liquid can reach rock channels &
pollute groundwater invisibly. If there is initially enough distance, biomat
is a self-sealing barrier so invisible pollution does not start later.
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Note that central sewers
fail more massively: Pipes crack, treatment can fail, sludge goes on soil as
thin as 6" over rock; pollution goes in streams & groundwater.[35]
©Stewards of the Potomac
Highlands,
Box 455, Wardensville WV 26851, an environmental nonprofit. Donations welcome
but not tax-deductible, since we lobby. Footnotes/sources are on PotomacStewards.com OK to reprint if you
reprint this whole page.
Sources & Links SFQ means Small Flows Quarterly, published by National Small
Flows Clearinghouse
Pipeline NSFC means the newsletter of that
name published by National Small Flows Clearinghouse
Pipeline WVPSC means the newsletter of
that name published by the WV Public Service Commission
[3] "Homeowner's Guide to Septic Systems"
EPA-832-B-02-005, 2002, p.11
"Q+A, Drainfield Inspection" SFQ Spring 2004
v.5 no.2, p. 42 and
"Letter II" " SFQ Fall 2004 v.5 no.4
p.19 and
"Water Softener Use Raises Questions for System
Owners" Pipeline NSFC Winter 2001 v.12 no.1. Page 4 says calcium
keeps the sodium chloride from clogging the drainfield. Page 6 says potassium
chloride may hurt bacteria less. No research is cited on whether bursts
of potassium or sodium hurt bacteria in normal anaerobic septic tanks.
[5] Electronic softener on incoming water pipe is designed to
precipitate calcium ions into aragonite, which leaves water soft, does not
cling to pipes, passes into drainfield and soil. Opinions differ whether it
works. The effect of aragonite on drainfields is unreported, but it dissolves
readily in slight acidity, which the biomat may have.
"the system never completely clogs" in
"Q+A, How to Extend the Life of Your Drainfield" SFQ Summer
2003 v.4 no.3 p. 36 and
"Alternating Drainfields" Technical Overview
SFBLTO01 p. 3, in SFQ Spring 2004 v.5 no.2, after p.28 and
"Wastewater Infiltration into Soil" Winter 2004 v.5
no.1, p. 29
[8] "Graywater Use" SFQ Winter 2001 v.2 no.1 p. 20
[9] Business use needs over-sized system, because of more organic
waste per gallon and wider variations around the average flows. "The Best
Wastewater Systems Consider Flow Rate and Waste Strength" SFQ
Spring 2000 v.1 no.2 p.14
"Mystery behind PPCPs" SFQ Winter 2004 v.5 no.1,
p. 14 and
"Maine Passes Bill to Deal with Unused Medications" SFQ
Summer 2004 v.5 no.3, p.8
"Septic Tank Additives" SFQ Winter 2002 v.3 no.1,
p. 27
"Q+A, Drainfield Inspection" SFQ Spring 2004 v.5
no.2, p. 42
"Septic Tank Additives" SFQ Winter 2002 v.3 no.1,
p. 26 and
"Grease Traps" SFQ Spring 2002 v.3 no.2, p.
36.
There are allegations that Rid-XTM creates bubbles
which lift solids out of the septic tank so they clog the drainfield. Any
citations confirming or denying this allegation would be helpful. The National
Library of Medicine says Rid-X liquid is 100% "Subtilisin" (proteolytic
enzyme). The following are synonyms: Bacillopeptidase B; Subtilopeptidase C;
Subtilopeptidase B; Subtilopeptidase A; Bacillus subtilis enzyme fermentation
product; Bacillopeptidase A; Subtilisin; Bacillus subtilis carlsberg. The
powder is 40-43% "Subtilisin"as above, 20-24% Calcium carbonate
(Limestone), and the remainder unknown.
http://householdproducts.nlm.nih.gov/cgi-bin/household/brands?tbl=brands&id=18001048
Washington state identifies Rid-X as not harmful to human
health, and does not allow it to claim any reduced frequency of pumpouts
http://www.doh.wa.gov/ehp/ts/WW/Additives.DOC
The manufacturer's website has little information http://www.reckittprofessional.com/customer_services/msds/dist/
[15] "Pumping Your Septic Tank" Washington Sea Grant Program
3/03 and
"Watertight
Tanks" SFQ Summer 2004 v.5 no.3, p. 12
"Effluent Filters" SFQ Winter 2003 v.4 no.1, p.
38
[17] "Offensive Odors Don't Always Mean Septic System
Failure" SFQ Fall 2004 v.5 no.4 p.30
"Alternating Drainfields" Technical Overview SFBLTO01 p.
7, in SFQ Spring 2004 v.5 no.2, after p.28
[19] Water flows in soil at a
limited rate (percolation rate). If total of rain plus flushed water exceeds
this rate, water backs up in pipes; reduce the load by sending rainwater
elsewhere.
[20] Pipeline NSFC Summer 1995 v.6 no.3, p. 5
"Many references ... suggest pressure dosing is equivalent
to installing alternate drainfields"
in "Alternating Drainfields" Technical Overview
SFBLTO01 p. 5, in SFQ Spring 2004 v.5 no.2, after p.28 and
"Q+A, How to Extend the
Life of Your Drainfield" SFQ Summer 2003 v.4 no.3 p. 37 and
"Role of Biomats in Wastewater Treatment" SFQ
Fall 2001 v.2 no.4, p.36
but "Letter III" says iron & sulfur accumulate
in soil pores every time drainfield is saturated; SFQ Fall 2004 v.5 no.4
p.19
"Alternating Drainfields" Technical Overview SFBLTO01 p.
6, in SFQ Spring 2004 v.5 no.2, after p.28
"Gravelless System and Chamber System" SFQ Fall
2000 v.1 no.4, p 47 and
"Letter to the Editor" SFQ Summer 2004 v.5
no.3, p. 41 shows doubts about chamber system
"Soil Characteristics" Pipeline NSFC Spring
2002 v.13 no.2 p.5 and
"Chamber Systems are Easy to Install" SFQ
Fall 2003 v.4 no.4, p. 50 and
"Wastewater Infiltration into Soil" Winter 2004 v.5
no.1, p.38 and
"Gravelless and Chamber Systems" Pipeline
NSFC Summer 2001 v.12 no.3, p. 1
"High-Strength Flows" Pipeline NSFC Fall 2003
v.14 no.4, p. 4 and
"Development of an Enhanced Performance Septic Tank"
SFQ Winter 2001 v.2 no.1, p. 37
"STEP System Clears the Air" SFQ Winter 2001 v.2 no.1,
p. 28 and
"Small-Diameter Gravity Sewers" SFQ Spring
2001 v. 2 no.2, p. 24 and
"Sewage Disposal" Pipeline WVPSC Nov-Dec 2003
v.1 no.6
"Maintaining Home Aerobic Units" SFQ Spring 2003
v.4 no.2, p. 36 and
"Composting Toilets" SFQ Summer 2004 v.5
no.3, p.42 and
"Incinerating Toilets" SFQ Winter 2004 v.5
no.1, p. 54 and
"Tablet Chlorination" SFQ Summer 2004 v.5
no.3, p.54 and
"Build Your Own Constructed Wetland" SFQ Fall
2004 v.5 no.4 p.19
"Graywater Use" SFQ Winter 2001 v.2 no.1 p.
20 and
"Biological Filtration" Technical Overview SFBLTO02,
in SFQ Summer 2004 v.5 no.3, after p.28 and
"Matching the System to the Site" SFQ Winter
2001 v.2 no.1, p.14 and
"Quality Maintenance Key to ATU Performance in
Texas" SFQ Fall 2000 v.1 no.4, p 8 and
http://www.barnstablecountyhealth.org/AlternativeWebpage/Aerobic/Aerobic.htm
and
"Taking the Gush Out of the Flush" SFQ Winter
2004 v.5 no.1, p. 22
[27] "Hydrogen Peroxide Not Recommended to Unclog Failed
Drainfields" because it creates impermeable layer of fine sediment; SFQ
Spring 2000 v.1 no.2 p.14
Cost includes $16,000 pipes, $3,000 expanding treatment plant,
$3,000 closing septic, $3,000 higher monthly bills
[29] Tire chips are an alternative to gravel "Tire Chips, a Growing
Trend as Aggregate in Soil Absorption Systems" SFQ Fall 2003 v.4
no.4 p.14
"Landscaping Options" SFQ Spring 2004 v.5 no.2,
p. 21
[31] "Soil Absorption Systems" Technical Overview SFBLTO03, in
SFQ Fall 2004 v.5 no.4, after p.32 has much information on drainfields.
It says research shows that 24" of soil below trench, & above water
table or rock (whichever is higher), are enough to treat effluent. It notes
area of trench bottoms is average or peak gallons/day from the house, divided
by gallons/square foot/day which the soil can absorb.
"Alternating Drainfields" Technical Overview SFBLTO01 p.
3, in SFQ Spring 2004 v.5 no.2, after p.28 and
"In-Ground Dispersal of Wastewater Effluent" SFQ
Spring 2003 v.4 no.2, p. 32 and
"Wastewater Infiltration into Soil" Winter 2004 v.5
no.1, p. 29 and
"Role of Biomats in Wastewater Treatment" SFQ
Fall 2001 v.2 no.4, p.36
"Q+A, Drainfield Inspection" SFQ Spring 2004 v.5
no.2, p. 42
"Monitoring Effluent Plumes" SFQ Summer 2000 v.1
no.3, p. 40 and
"Septic System Performance Analysis Utilizing Color
Infrared Aerial Photography, Berkeley County WV" by Environmental Research
Inc, Linden VA, 1996 and
"Arkansas Sanitarian Uses Infrared Technology to Track Down
Sewage" SFQ Spring 2000 v.1 no.2 p.22
[35] "Think Septics Are Always Bad? Then You Don't Know
Sewage" SFQ Fall 2004 v.5 no.4 p.19 reprinted from Bay Journal May
2004 and
"When Systems
Fail" SFQ Fall 2004 v.5 no.4 p.20 and
West Virginia State Rules
47-31 App.B-A-2.2 expect well-designed new 8" diameter sewer pipes to leak
1,600 gallons/day/mile; and
Optimizing Operation,
Maintenance, and Rehabilitation of Sanitary Sewer Collection Systems New
England Interstate Water Pollution Control Commission 12/03 http://www.neiwpcc.org/omrmanual.htm
"Many collection systems are maintained by a public works department
charged with various functions, such as street, sidewalk, storm drain, and
sometimes water utility maintenance. Money is usually spent where the ratepayer
can see the results... The lack of proper maintenance has resulted in
deteriorated sewers with subsequent basement backups, overflows, cave-ins,
hydraulic overloads at treatment plants, and other safety, health, and
environmental problems. As one of the most serious and environmentally
threatening problems, sanitary sewer overflows - or SSOs - are a frequent cause
of water quality violations and are a threat to public health and the
environment." p. 1-2. " Since these sewers[crossing streams]
are often in remote locations, they are susceptible to vandalism and can
overflow for long periods of time without detection." p. 7-3 and
Report to Congress:
Impacts and Control of CSOs and SSOs EPA 8/24/04 http://cfpub2.epa.gov/npdes/cso/cpolicy_report2004.cfm