On-Site Sewage Treatment and Disposal Systems

On-site sewage treatment and disposal systems (OSTDS) are typically individual on-lot systems sized for a home, apartment building, or a small neighborhood and are appropriate for rural areas. They can be connected to form a local neighborhood or small community-scale treatment cluster system. OSTDS comprises septic tank technology constructed of watertight chambers made of brick work, concrete, fiberglass, PVC, or plastic. Blackwater and greywater pass through a pipe from inside a building or an outside toilet to the septic tank and then flow on for primary treatment. Settling and anaerobic processes reduce solids and organics. Effluent is infiltrated into the ground or transported via a sewer to a community-scale, centralized treatment plant. Septic tank systems are relatively inexpensive and simple to maintain. While this technology is typically used for primary treatment of blackwater and greywater, it can be upgraded to include nitrogen and phosphorus treatment as secondary treatment.