What type of wastewater treatment system uses septic tanks as an example?

Septic tanks are a key component of decentralized wastewater treatment systems. These systems are typically utilized in rural or less densely populated areas where connecting to a centralized sewer system may not be feasible or cost-effective.

Decentralized systems manage wastewater on-site and often include a range of treatment methods, such as septic tanks, which collect and partially treat the wastewater through processes like sedimentation and bacterial digestion. After initial treatment in a septic tank, effluent is usually further treated through soil absorption systems or other methods, allowing for safe infiltration into the environment.

In contrast, centralized systems involve larger-scale treatment facilities that process wastewater from multiple homes or buildings. Activated sludge systems fall under centralized processes, utilizing aeration tanks and other methods to treat wastewater on a larger scale rather than on an individual basis. Mechanical treatment systems typically refer to processes that involve physical methods to separate solids from liquids and may not incorporate biological treatment in the same way septic systems do.

Understanding these distinctions helps clarify why systems like septic tanks are representative of decentralized, on-site treatment options rather than centralized or mechanical approaches.