Some homes for which septic systems are not a good option rely on individual home aerobic systems for waste-water treatment. Aerobic systems are similar to septic systems in that they both use natural processes to treat waste-water. Many homes in the U.S. are located in small or rural communities where houses are spaced widely apart. In these communities, central sewerage systems are often not cost-effective, so many home-owners rely on septic systems or other systems that treat and dispose of household waste-water onsite. But unlike septic (anaerobic) treatment, the aerobic treatment process requires oxygen. Aerobic treatment units, therefore, use a mechanism to inject and circulate air inside the treatment tank. This mechanism requires electricity to operate. For this reason, aerobic systems cost more to operate and need more routine maintenance than most septic systems. However, when properly operated and maintained, aerobic systems can provide a high quality wastewater treatment alternative to septic systems.

Why choose aerobic treatment?

Although there have been home aerobic systems in the U.S. for more than 50 years, their use has been fairly limited. This is due, in part, to the widespread use of septic systems. Septic tank-soil absorption systems are relatively inexpensive and are easy to maintain. They are the most common onsite wastewater treatment systems used in rural areas. However, there are many households for which a septic system may not be the best wastewater treatment option. For example, septic systems are not suitable for every lot. In fact, approximately two-thirds of all the land area in the U.S. is estimated to be unsuitable for the installation of septic systems. Home-owners in wooded areas may not want to clear enough land to install a septic tank and drainfield, and the wastewater treated by a septic system is often not of high enough quality to be discharged very close to a body of water. Some homes may not have enough land area or appropriate soil conditions to accommodate the soil absorption drain-field. In some communities, the water table is too high to allow the drain-field to give adequate treatment to the wastewater before it is returned to the ground-water. Other site-related concerns include homes located on wooded lots or on lots close to a body of water. But one of the most common reasons that aerobic wastewater treatment units are chosen by communities is to replace failing septic systems. Failing septic systems are a major source of ground-water pollution in some areas. If a failed septic system needs to be replaced or if a site is inappropriate for conventional systems, aerobic waste-water treatment becomes a viable option.