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Where Does the Water Go?Do you know
where the water goes when you empty a sink or flush a toilet? If your home is in
a city, the wastewater goes into a municipal sewer system and to a sewage
treatment plant. If your home is in a rural area or a small community, chances
are there is no municipal water and sewage service available and your wastewater
goes to your own private septic system. A septic system treats and disposes of
your sewage right in your own yard. There's Sewage in My Yard?The septic
system, when performing properly, safely treats and disposes of your sewage
without creating any danger to your health or to the environment. Normally you
don't have to worry about sewage in your yard. However, if the septic system is
not functioning properly, there can be health concerns. Therefore, it is a good
idea to understand how a septic system works and what you can do to make sure it
continues to work properly. But I've Never Even Seen My Septic System!Most people have
never seen their septic system, and if the system is properly maintained, most
may never need to see it. A septic system is generally composed of two main
parts: a watertight septic tank and a network of perforated pipes, called a tile
bed or leaching bed. All these parts are buried under your lawn so you may not
even be aware of them. Yet, your septic system receives all the wastewater from
your house, including toilets, showers, sinks, dishwasher, washing machine, etc.
and purifies that water so it is safe to re-enter the ground water system. How Does My Septic System Work?The purpose of
the septic tank is to separate the solids from the liquids in the wastewater
stream and to begin the process of breaking down contaminants.The septic tank
can be constructed of concrete, steel, fibreglass or polyethylene and can range
in size from about 2,300 litres to 5,000 litres.To give you an idea of how large
this is, consider that up to 200 litres of water fit in a standard bathtub and
ordinary toilets use up to 20 litres per flush. So, depending on the size of
your household, it doesn't take too long to fill the septic tank. But that's
okay, because that's how the septic system is designed to work. The septic tank
typically has two interior chambers. The wastewater from your house, called
“influent”, enters the first chamber and its velocity slows so that the
heavier solids can settle out of the water into the bottom of the chamber, and
lighter materials can float to the surface. The accumulation of settled solids
at the bottom of the tank is called “sludge” and the lighter solids (greases
and fats) which form a mass on the surface of the liquid in the septic tank is
called “scum”. In between the sludge and the scum is liquid waste.
Micro-organisms, like bacteria, and other natural processes act to decompose the
waste materials in the liquid waste. Sludge and scum are also digested and
compacted into a smaller volume. This is the first step in the process of
purifying your household wastewater. When the first
chamber of the tank becomes filled, the liquid waste begins to fill the second
chamber. The chambers of the septic tank are designed to prevent the movement of
sludge and scum to the second chamber, allowing only the movement of liquid.
Once the second chamber is filled, as more influent enters the first chamber, an
equal amount of the partly-treated liquid waste flows into the second chamber,
while an equal amount flows out of the second chamber into the leaching bed. The
water flowing out into the leaching bed is called “effluent”. The purpose of
the leaching bed is to further treat the wastewater. A gridwork of perforated
pipes or clay tiles in the leaching bed area evenly distributes the effluent
over the natural soil or imported fill. Sometimes a distribution tank is used at
the head of the pipes to more evenly distribute the effluent to the pipes. The
perforations in the pipe allow the effluent to escape to the soil. As the
effluent filters through the soil, micro-organisms in the soil digest and remove
the remaining impurities (such as suspended solids, organic chemicals and
viruses and/or bacteria). Eventually, the purified water reaches the
groundwater. As you can see,
the operation of your septic system is fairly automatic and can work quite well
by itself with very little maintenance required by the homeowner. Note the key
words though, “little maintenance”, not “no maintenance”.
What Do I Need to Do to Keep My Septic System Working?Over time, the
sludge will build up in the bottom of the septic tank. The rate of the build-up
will depend on the size of your tank (bigger is better), the volume of
wastewater entering the tank, and the volume of solids in the wastewater stream.
If the sludge is allowed to accumulate to the height of the outlet pipe, it
could flow into the next chamber and then out into the tile bed. The pipes in
the tile bed can become rapidly clogged by sludge. When the pipe is all blocked
and the wastewater can no longer leach into the soil, it will seep to the
surface of the ground, or worse yet, back up into your house. Not only can a
clogged septic system be hazardous to the environment and to your family's
health, it also represents a very expensive repair bill. Once the pipes become
clogged, there is no quick fix; the entire system must be dug up and replaced. To prevent the
clogging of the system, every two to five years (depending on the tank size and
use of the system), a licensed sewage disposal contractor should be hired to
pump out the tank to remove the build-up of sludge. Pumping should be more
frequent for a smaller tank, where more people are living in the house, and for
houses with garbage disposals. Not only will this increase the capacity of the
system by creating more room for the wastewater, but it will also prevent the
sludge from entering the tile bed area. The best time to clean out the tank is
summer to early fall. At these times, the ground will not be frozen, allowing
easier access to the tank, and the biological activity in the tank can
re-establish itself before it gets too cold (micro-organisms like it warm). In
the spring, a high water table caused by melted snow can sometimes create
sufficient pressure on the underside of an empty tank to push it up out of the
ground. This is more of a concern with lighter tanks made of polyethylene,
fibreglass or steel.
Because septic
systems rely on microscopic organisms to break down the waste material, it is
important that you don't “poison” these organisms. Even small amounts of
paints, solvents, thinners, nail polish remover and other common household
compounds flushed or poured down the drain can kill the organisms that break
down organic material. Laundry bleaches, toilet bowl cleaners and caustic drain
openers can also slow the treatment process, allowing sewage to pass through to
the leaching bed without proper treatment. However, moderate use of these
materials should not interfere with the operation of the septic system. Some
manufacturers promote the use of septic tank “cleaners”, “starters” or
“enhancers” to aid in the digestion of the waste. These products are
typically of little value, and in some instances may actually kill essential
bacteria, so they are not recommended. You should avoid
putting anything into the septic system that doesn't break down naturally or
anything that takes a long time to break down. Materials such as oils, grease,
and fat, disposable diapers, tampons and their holders, condoms, paper towels,
facial tissues, cat box litter, plastics, cigarette filters, coffee grounds, egg
shells, and other kitchen wastes, should never be put into the septic system.
You should also avoid the use of in-sink garbage disposal units (“Garburators”). You can also
prolong the life of the septic system by controlling the amount and timing of
wastewater you put into the system.
I Need to Control My Water Usage?Every time you
put water into the septic tank, that same amount of water moves into the
leaching bed. So, the faster you put the water into the tank, the faster it
moves into the leaching bed. However, it takes time for the solids to settle out
of the liquid waste and for the micro-organisms to digest the solids. The longer
the “retention time”, - the time that the wastewater is allowed to remain in
the septic tank, the more purification that occurs. If you cause the water to
move too quickly through the system, less purification occurs before the water
reaches the leaching bed and the effluent may be discharged to the soil while
still containing dangerous pollutants in unacceptable concentrations. Therefore,
whenever possible, you should try to regulate the amount of water entering the
septic system. For example, rather than doing all the laundry on a Saturday,
spread the work over the week by doing only one load a day. You can also reduce
water usage by installing water saving features in plumbing fixtures and by only
running the washer or dishwasher when it is full. Try taking shorter showers
rather than full baths. And fix leaky faucets! A tap leaking just one drop per
second wastes about 10,000 litres of water per year. A silently leaking toilet
can waste up to 20 times that amount. Lastly, ensure that foundation drainage,
surface water from roofs, yards, garage floors and other sources of oily wastes,
furnace condensate, and water softener backwash is excluded from the septic tank
and the disposal field. Sludge build-up
can also reduce retention time, which is another good reason to regularly pump
out the tank. The last thing
you need to be concerned with is the condition of the leaching bed.
How Do I Look After the Leaching Bed?Looking after
the leaching bed is easy. There's nothing you have to do, but there are a few
things you shouldn't do. The area over
the leaching bed should have a good cover of grass. Good ventilation and
adequate sunlight should also be maintained to promote evaporation. This means
that you should avoid constructing parking areas, patios, tennis courts or decks
in the area of, or over, the leaching bed. The weight of such constructions
could crush the pipe in the leaching bed preventing it from working properly.
Covering the leaching bed could also prevent oxygen from getting into the
soil.The micro-organisms responsible for digesting the waste material need
oxygen to survive and function. You should not
drive vehicles or machinery over the bed, as the weight could crush the pipe.
Also, if the soil over the pipes becomes compacted, it will be less able to
absorb the wastewater. In winter, you should also keep snowmobiles off the
leaching bed. The compaction of the snow will reduce its natural insulating
effect, increasing the chances of the pipes freezing. Don't plant
trees or shrubs near the leaching bed. The roots of some trees, especially
willows and poplars, will travel significant distances to reach water. The roots
can plug and damage the tile. Lastly, don't
water the grass over the leaching bed. The additional water may interfere with
the ability of the soil to absorb liquids and break down waste. Looking after
your septic system is easy, and if you follow all the suggestions for
maintaining your septic system and prolonging its life, it should last twenty
years or longer - and that's based on year-round use. Unfortunately, just like
many building components, eventually all septic systems will need to be
replaced. How Will I Know if I Have a Problem with My Septic System?Some of the
warning signs that your septic system may be failing include the following:
What If I Have to Repair My Septic System?If you notice
any of these problems, it is important that you take action immediately to
protect your health and your environment. Contact a licensed contractor to
advise you on how to proceed. Repairs can range from clearing a few lines, to
replacing entire leaching beds and removing contaminated soil and costs can vary
from a few hundred dollars to a few thousand dollars. You are also
required by law to report any problem to your Local Health Unit before
proceeding with repairs. A final inspection will need to be carried out and a
Use Permit granted before you can legally use a new or altered septic system. Your contractor
and/or your Public Health Unit can also help you determine the required size of
your septic system. The size of the tank and the area of the leaching bed depend
on a number of factors, including the size of your household (which is related
to the expected water usage and load on the septic system), and the type of soil
on your property. Some soils are better at absorbing liquid waste than others.
The ideal location for a leaching bed is in well-drained sandy loam soil. If the
soil is silt and/or clay, a larger leaching bed may be required. You may find
that you need or want a larger system than you currently have. When it comes to
septic systems, bigger is typically better. If you have a sloped site, you
should contact your local Health Unit to discuss alternatives to the
conventional system described here. If you are
repairing, replacing or installing a new septic system, you will also have to be
aware of the legal limitations imposed on where your septic system can be
located with respect to your house and your well, your neighbour's house and
well, and nearby bodies of water. These distances are required to help ensure
that wastewater from your septic system cannot reach and contaminate nearby
water supplies. What Are the Limitations Imposed on the Placement of My Septic System?While the
specifics may vary, depending on your jurisdiction, the following are some of
the minimum distances required. Septic tanks
should not be closer than:
Distribution
pipe in the leaching bed should not be closer than:
If the surface
of the leaching bed is raised above natural grade, the above clearances must
typically be increased by 2 metres horizontally for each 1 metre raised. In some cases,
it may be impossible to meet these minimum distances and still construct a
leaching bed big enough to meet your needs. Fortunately, there are some
alternative technologies that may allow you to reduce the size of your system. What Other Types of Systems are Available?If it is
impossible for you to install a leaching bed, perhaps due to the size of your
lot, some jurisdictions will allow the installation of a holding tank in
replacement situations. Holding tanks are not typically permitted as the only
source of sewage treatment for a new house. The holding tank is designed simply
to store wastewater, which is then pumped from the tank and trucked off-site for
treatment. Typically you must have an on-going contract with a pumping service
to ensure your holding tank is cleaned out on a regular basis. To ensure these
systems never overflow, they are equipped with an alarm that will sound when the
tank is nearly full. There are also
several mechanical alternatives to septic systems available. These systems,
called Aerobic Systems, work by using a compressor to bubble air through the
wastewater or by using rotating discs to expose the sewage to air. The
introduction of air into the wastewater helps the micro-organisms break down the
waste, providing a higher level of treatment than standard septic tanks.
However, these systems employ mechanical parts that require uninterrupted
electrical connections and regular servicing, such as lubrication. Some Local
Health Units have been hesitant to approve these designs, because of problems
that have arisen from improperly maintained systems. As a result, aerobic
systems often require the same size drainage field as a standard septic system. Other types of
pre-treatment units use different materials, such as special sands, peat or
other filter materials. These systems are becoming increasingly popular because
of the quality of the wastewater they produce and because they can reduce the
overall size of the septic system, especially the leaching bed.The Waterloo
Biofilter is an example of a technology that can be used in areas with little
property, areas with surface bedrock or in northern locations were temperatures
are prohibitive. Research into improved mechanical systems, better biological
treatment media and systems using wetland or aquatic plants appears very
promising. You should contact your Local Health Unit to find out what kinds of
systems may be considered for approval in your area. |
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