What is a septic tank?
A septic tank is a type of biological sewage treatment system. Naturally occurring bacteria break down the solid matter, reducing its volume. The liquid element is discharged usually via effluent drainage systems “soakaways” The accumulated solids need only be pumped out occasionally by a licensed contractor. Like cesspools, they may be constructed in brick or blocks, although modern types are pre-formed in reinforced fibreglass. Consent to discharge the treated effluent may be required from the Environment Agency.
A septic tank is a large tank meant to store sewage waste while it settles. The septic tank design is used by nearly a fourth of the population in the United States, and is also widely used throughout the world. The septic tank is one part of a standard rural septic system, the other part being the leach field. Sewage enters the septic tank from the house where it is left to separate. Heavy solids settle to the bottom of the septic tank, while the relatively clear water rises to the top where it is allowed to leach off into the earth. Once in the leach field, any remaining solids are taken care of, and the water rejoins the greater water table. Solids left in a septic tank mostly break down through the digestion of anaerobic processes. Not all the solids will work their way out, however, and occasionally a septic tank must be drained before it reaches capacity. The speed at which this filling occurs depends on the size of the septic tank, the amount of waste being pumped into it, the t
In many areas that do not have the capability to run public wastewater hookups to homeowners, septic tanks are installed to digest waste that otherwise would go to a treatment facility on a municipal system. Septic tanks are generally made out of concrete, fiberglass or steel and are normally buried outside of the home acting as a catch basin for waste flowing from commodes, sinks, showers and often washer machines. Septic tanks vary in sizes anywhere from 300 gallons to 30,000 gallons or more depending on the facility the tank is serving. The diagram below displays an average septic tank system with lateral lines running to a drainfield. Inside the tank, liquids and solids are separated naturally and form three distinctive layers know as the scum layer (top layer), clear layer (middle effluent layer) and sludge layer (bottom layer). In most systems, the effluent layer is allowed to pass out into a drainfield or leachfield where the liquid is broken down biologically by naturally occur
The typical septic tank is a large buried rectangular or cylindrical container made of concrete, fiberglass or polyethylene. Wastewater from your toilet, bath, kitchen, and laundry flows into the tank. Heavy solids settle to the bottom where bacterial action partially decomposes them to digested sludge and gases. Most of the lighter solids, such as fats and grease, rise to the top and form a scum layer. Septic tanks may have one or two compartments. Two compartment tanks do a better job of settling solids and are required for new systems. Tees or baffles are provided at the tank’s inlet and outlet pipes. The inlet tee slows the incoming wastes and reduces the disturbance of the settled sludge. The outlet tee keeps the solids or scum in the tank. All tanks should have accessible covers for checking the condition of the baffles and for pumping both compartments. If risers extend from the tank to or above the ground surface, they should be secure to prevent accidental entry into the tank.
