Choosing the best septic tank design generally involves weighing the pros and cons of different septic tanks against your specific needs. Septic tanks come in different sizes and materials. They can be single-chambered or multi-chambered. Septic tank design varies by functionality, but they are all designed to treat liquid and solid waste as efficiently as possible.
Septic tanks are typically made of concrete, polyethylene, or Plexiglas®. They come in various sizes but must be chosen according to local health department regulations and the size of the home they service. Designed to retain wastewater for at least 24 hours, a septic tank typically needs to have at least a 750-gallon (2,839 liters) capacity. A home with more than two bedrooms generally requires 250 gallons (946 liters) for each bedroom. In other words, a five-bedroom home typically requires a septic tank that can hold 1,250 gallons (4,731 liters) of wastewater for a full day.
Conventional septic tanks are one unit. Waste from a residence flows into the septic tank where solids settle on the bottom and become sludge. Oils and grease float on the remaining liquid waste. The liquid waste flows out into drainfields, also known as leachfields. The septic tank slowly fills up with sludge and scum and must be pumped out every three to five years--when it is emptied depends on its size, water usage and the amount of food debris emptied into the tank.
If you live in an area with poor soil or not enough land for a conventional septic tank design, you can add additional filters to aid in decomposition of waste water. A reciruculating sand filter or peat filter set-up can usually filter out enough harmful bacteria contained in waste to compensate for shorter drainfields or non-porous soil beds. Many septic system additive manufacturers say their products contribute beneficial organisms to the septic system that can adequately break down pathogens before they reach groundwater.
Septic tank maintenance is generally crucial to the functionality and longevity of an effective septic tank design. Many waste management experts recommend yearly inspections and regular pump-outs. Keeping the house plumbing leak-free and monitoring the drainfields for soft spots and seeping sludge are typical ways to protect your chosen septic tank design.
Other generally-advised septic system care practices include protecting the drainfields from being saturated with irrigation or rainfall. Parking or driving over drainfields can also damage your septic system. Using your toilet as a trash receptacle can add solids to the septic tank that the anaerobic bacteria are unable to decompose.