Septic tank
While a properly maintained and located septic tank does not pose any more environmental problems than centralized municipal sewage treatment, certain problems can arise with septic tanks in unsuitable locations. Since septic systems require large drainfields, they are not suitable for densely built areas.
Septic tank
Wastewater enters the first chamber of the tank, allowing solids to settle and scum to float. The settled solids are anaerobically digested, reducing the volume of solids. The liquid component flows through the dividing wall into the second chamber, where further settlement takes place. The excess liquid, now in a relatively clear condition, then drains from the outlet into the septic drain field, also referred to as a leach field, drain field or seepage field, depending upon locality. A percolation test is required prior to installation to ensure the porosity of the soil is adequate to serve as a drain field.