Blog - Maintenance

Why should I have a septic system filter

Septic system filters are only important for one reason. They will lengthen the life of your septic system tile bed.

Since 2007 it has been mandatory to have a septic system filter installed on any new septic system. If a septic filter is installed in the system, a riser system should also be installed to grade level to facilitate servicing of the filter as well as the septic tank inlet baffle.

Effluent from the house to the septic tank has an average value of 300 mg/L of BOD (biological oxygen demand) and TSS (total suspended solids). Through anerobic digestion and settling, the waste strength of this effluent is lowered to 100 mg/L when it leaves the tank. The organic material contained in this effluent is what causes a biomat to form over time in the septic bed eventually causing failure gradually over a 25 year lifespan. The filter helps to contain a portion of this organic material. This lowers the amount of organic material going to the tile bed, which will extend the life of the tile bed. When you see a filter that is blocked after a year, you realise that the material trapped in the filter would have ended up in the tile bed. The amount trapped in the filter is quite dramatic.

Septic system filters come in many sizes that can vary by the number of litres/day design flow and also the size of the filter mesh or screen size (1/32 or 1/16) . These variables have to be taken into consideration when calculating the service interval and effluent quality desired.

Some of the smaller filters will have to be serviced every 6 months to a year depending on the use. Larger filters can last up to three years depending on the
loading rate from the household. The problem with yearly servicing is that most people forget (like furnace filters and other routine household chores). If the larger filters are used the capital costs go up but the service interval is longer and the pumper you use can clean it when they clean the septic tank. You avoid having to remember to tell your wife it’s time to clean the septic filter dear.
You know it’s my birthday or maybe it’s father’s day.

If you need sizing information or a filter installation call Bill Seabrook at 613-229-3900.