Septic Tank FAQs
How does a septic tank work?
A typical septic system contains two major components: a septic tank and the soakaway.
The septic tank is usually made of concrete, fibreglass, or plastic, is typically buried and should be watertight. All septic tanks have dip pipes at the inlet and outlet to ensure solids are retained in the tank.
Most septic tanks are dual-compartment, although a number of single compartment tanks are also used.
While typically designed to hold a minimum of 750 to 1000 gallons of sewage, the size of the tank may vary depending upon the number of bedrooms and occupants in the home or to comply with local regulatory requirements.
The primary purpose of the septic tank is to separate the solids from the liquids and to promote partial breakdown of contaminants by micro-organisms naturally present in the wastewater. The solids, known as sludge, collect on the bottom of the tank, while the scum floats on the top of the liquid. The sludge and scum remain in the tank and it is this that requires regular removal by de-sludging.
Solids that are allowed to pass from the septic tank may block the soakaway. Keeping solids out of the soakaway not only prevents blockages, but also reduces potentially expensive repair or replacement costs and helps ensure the ability of the soil to effectively treat the septic tank waste water (effluent).
An additional safeguard in keeping solids out of the soakaway is therefore the use of effluent filters on the outlet of the septic tank.
The effluent coming out of the septic tank may contain many potentially disease-causing micro-organisms and pollutants (e.g., nitrates, phosphates, chlorides). The effluent is passed on to the soakaway through a connecting pipe or manhole.
The soakaway contains a series of underground perforated pipes. The effluent is distributed through the perforated pipes, exits through the holes in the pipes and trickles through the rock or gravel where it is stored until absorbed by the soil.
The soakaway, which is located in the unsaturated zone of the soil, treats the wastewater through physical, chemical, and biological processes.
The soil also acts as a natural buffer to filter out many of the harmful bacteria, viruses, and excessive nutrients, effectively treating the wastewater as it passes through the unsaturated zone before it reaches the groundwater.
Waste water contains nutrients, such as nitrates and phosphates, that in excessive amounts may pollute nearby waterways and groundwater supplies. Excessive nutrients in drinking water supplies can be harmful to human health and can degrade lakes and streams by enhancing weed growth and algal blooms. However, the soil can retain many of these nutrients, which are eventually taken up by nearby vegetation.
What can I put in? What should I keep out?
Direct all wastewater from your home into the septic tank. This includes all sink, bath, shower, toilet, washing machine and dishwasher waste. Any of these waters can contain disease-causing micro-organisms or environmental pollutants.
Keep roof drains, cellar sump pump drains and other rainwater or surface water drainage systems out of the septic tank and away from the site of the soakaway. Flooding of the soakaway area with excessive water will prevent the soil from allowing the waste water to "soak away", which can lead to groundwater and/or nearby surface water pollution.
Conserve water to avoid overloading the septic tank system. Be sure to repair any leaky taps or toilets. Use low-flow fixtures.
Do not use caustic drain openers for a blocked drain. Instead, use boiling water or a drain snake to clear blockages.
Use commercial bathroom cleaners and laundry detergents in moderation. Many people prefer to clean their toilets, showers, and baths with a mild detergent instead.
How do I maintain a septic tank?
Often overlooked or neglected is the fact that a septic system should have a regular check-up to prevent problems. You should have your septic system inspected every 1 – 2 years by a professional and your tank should be de-sludged when necessary.
The septic tank traps the solids in the waste water and should be checked to determine whether or not it is time for it to be emptied out. The manhole should be opened and the dip pipes should be checked to ensure that they are in good condition since the last check-up.
If you have a septic tank effluent filter, it should also be inspected. Effluent filters require periodic cleaning. Some filters are now equipped with alarm systems to alert the homeowner when the filter has become dirty and needs to be cleaned. Failure to keep the filter clean may result in a backup of wastewater in the home from a clogged filter.
Septic systems that have mechanical parts such as a pump should be inspected at least once a year or more frequently as recommended by the manufacturer.
The soakaway should be checked for sogginess or ponding, which indicates improper drainage, a blocked system, or excessive water use. The presence of damp or soggy areas or odours may indicate a leak in the system.
How often should I have my septic tank emptied?
A specific determination of when it is time to pump out the solids can be made by having the depth of solids and level of scum build-up on top of the wastewater in the septic tank checked periodically.
Whether you need to have your septic tank de-sludged every year or once every five years, there are two factors which should be considered.
Firstly the size or capacity of the tank itself. The more people using a system, the faster the solids will accumulate in the tank, and the more frequently the tank will need to be de-sludged. If more people are living in the home than when the system was first installed, or if new high-water-use appliances such as a hot tub or whirlpool bath are now in use, then the capacity may be too small. An additional surge of water from hot tubs and whirlpool baths can force solids out of the tank and into the soakaway. An inspection can determine whether the system is adequate to handle the volume of solids and flow from the number of people in the household and the types of appliances being used. A larger capacity system provides better treatment and requires less frequent de-sludging.
Secondly the volume of solids in the wastewater. If you have a waste disposal unit, you will need to de-sludge your system more frequently. The use of a waste disposal unit will increase the amount of solids in your septic tank by as much as 50 percent. Excessively soiled clothes will also add solids to your septic tank. Sometimes, your geographical location may also contribute to extra solids building up in your septic tank. For example, systems in coastal areas have been known to accumulate sand in the septic tank from washing beach clothes
How do I care for the soakaway?
The soakaway generally does not require any maintenance. However, to protect and prolong its life, you should follow these simple rules:
Only plant grass over and near your septic system. Roots from nearby trees or shrubs may block and damage the site of the soakaway.
Do not drive or park over any part of your septic system. This can compact the soil and crush your system.
Direct all waste water from your home into the septic tank. This includes all sink, bath, shower, toilet, washing machine and dishwasher waste waters. Any of these waste waters can contain disease-causing micro-organisms or environmental pollutants.
Keep roof drains, cellar sump pump drains and other rainwater or surface water drainage systems out of the septic tank and away from the site of the soakaway. Flooding of the soakaway area with excessive water will prevent the soil from allowing the waste water to "soak away", which can lead to groundwater and/or nearby surface water pollution.
If you need any more advice, please get in touch. |
