This system's treatment mechanisms are physical filtering and ion exchange. By applying small amounts of effluent over a large area, evaporation is maximized, as is plants' ability to take up water and nutrients. The system is slightly larger than a conventional trench system. Although adding the effluent slowly over a large area increases treatment efficiency, lines freezing in winter can be a problem. Aerobic tanks are, however, considerably more complicated to design, construct and maintain than septic tanks.
Aerobic tanks are available in residential or small-community sizes.
In either case, these tanks require more maintenance than conventional septic tanks. If problems arise with the supply of air to the bacteria, an aerobic tank loses all its effectiveness. It's critical that aerobic tanks be monitored regularly and repaired as needed. For community aerobic tanks, there is a single location that needs checking and maintenance. Individual aerobic tanks provide multiple opportunities for problems and each one must be inspected as frequently as larger tanks.