How a Septic System Works
A septic system consists either of a septic tank and a weeping bed or a septic tank and a tertiary system, which may or may not have a weeping bed.
Anything which goes down your drain will exit the house through an underground pipe and enter the septic tank. The tank itself consists normally of two chambers. The first chamber allows the heavier solids to settle to the bottom of the tank, the second chamber allows for finer solids to settle. A layer of scum is common in many septic tanks and generally consists of toilet paper, oils, grease, fats and soap.
A septic tank is always “full” in that the level should remain constant. The level should be just below the outlet pipe (the one leading from the tank to the weeping bed or tertiary system). Every time waste water enters the septic tank, the same amount will exit it as a result of displacement.
Organic materials which are in the tank will be broken down by anaerobic bacteria, and a certain degree of treatment is therefore achieved.
Modern tanks (generally since January 2007) will contain an effluent filter. This is located at the outlet pipe and prevents solids from entering and clogging the weeping bed or tertiary system. It also allows for more treatment of solids to occur by the bacteria in the tank.
A video from the Ontario Ministry of Agriculture, Food and Rural Affairs
how your septic system works.
Septic System Approval Process
Septic Inspections
How To Perform a Good Inspection
How can you accurately inspect a septic system?
Lets first look at what a septic system has to be doing correctly to be considered a properly functioning system:
Bacteria within the tank and bed must convert complex organic matter such as toilet paper, fecal matter, ammonia, fats, oils, greases, etc into basic molecules such as water, nitrogen, and co2. If the bacteria are not breaking down the complex molecules then the system will fail because untreated sewage will simply pile up and prevent all sewage from entering the soil. The septic tank is capable of treating up to 60% of the sewage if it is working properly. The remaining 40% must be treated within the treatment/disposal bed area.
The efficiency of a septic system can easily be assessed by looking at the bacterial health within the tank AND in the treatment/disposal bed.
A common practice within the septic industry is to only look at the septic tank to identify how well the system is working. Unfortunately though, the tank is rarely the part of the system that fails and needs to be replaced. A treatment/disposal bed failure is what causes the septic tank to back up and “fail”.
By locating and uncovering a very small section of the bed we can identify where on the scale of “failure” the system is. If the system is only partially failed then it may be possible that the system can be revived with proper maintenance. If the failure is more advanced then other actions can be recommended to reverse the failure. It is also necessary to look for root and dirt damage within the septic bed with a sewer camera whenever possible.
Good trench
Partially fixed
