A First Look At The Primary Treatment, The Septic Tank:
A typical home with a septic system will have a septic tank, it is either a concrete, plastic or fibreglass chamber that is used for the partial treatment of domestic wastewater and for retention.
The septic tank by itself will not achieve a high degree of sewage treatment. The initial role is to prevent clogging in the field by conditioning the sewage through the separation of solids, oils and fats.
This is done by the floating and settling of suspended solids which will anaerobically decompose in the septic tank. The lighter weight matter such as fats and soap residue will stay on the top portions of the tank causing what is called a scum layer.
The heavier organic matter will then settle to the bottom and begin to decompose. The liquid in between the two layers that should be partially clarified will then flow through the outlet baffle towards the next component of the septic system.
The initial step in designing a septic system in BC is identifying the proper sizing of the septic tank, and identifying the right type of tank; a concrete, plastic, one compartment, two compartments or even having multiple tanks.
A septic tank with a single compartment performs an acceptable household wastewater treatment, two compartment tanks should improve the biochemical oxygen demand or (BOD) and the (TSS) or total suspended solids removal.
The septic tank is sized to the amount of household expected flow.
