Tank and field
Standard soil-based treatment systems use a septic tank for initial treatment. The household plumbing collects wastewater and sends it to the septic tank which acts as a separation chamber. Heavy particles separate from the wastewater and settle to the bottom to form a sludge layer. Lighter particles, mainly soap, grease and toilet tissue separate and float to the top to form a scum layer. Using a baffle device the clearest liquid from the center of the tank flows by gravity to the effluent dosing chamber. A pump or siphon in the effluent dosing chamber will deliver the effluent to the final soil treatment component, in this case the septic field.
Tank and sand mound
As discussed above, the household plumbing collects the wastewater and sends it to the septic tank where it is separated into the three layers, sludge, scum and wastewater. Once the wastewater enters the effluent dosing chamber of the septic tank, the pump in the effluent dosing chamber delivers the effluent to the mound system. In a mound, pressure distribution pipes are placed in a bed of aggregates or chambers with a 12” layer of sand below. The wastewater is pumped into the pressure distribution system and sprays into the sand layer, where aerobic bacteria cleans the water. Mounds must be landscaped with grass and be regularly maintained in order to have improved efficiency.
Advanced Treatment Plant
Other options for initial treatment components are manufactured packaged sewage treatment plants. They may have components, such as textile filter systems and aeration devices. These components, like a septic tank, will receive all the wastewater generated by the facility they serve. These systems will produce cleaner effluent and are considered to be advanced treatment systems. Cleaner effluent increases the percolation rate of effluent through soil pore spaces during the final treatment component.
Open Discharge or Ejector Systems
Open discharge systems are sometimes used on farms or acreages. In this system waste enters the septic tank and the wastewater is discharged through a pipe system onto the open property. There are strict provincial guidelines on size of property required to run a direct or open discharge as the discharge must occur a certain distance from the property line and any water source on the property or within a certain radius of the discharge.