Date of Award


Document Type


Degree Name



Systems Engineering

Committee Chair

Dr. Robert J. Cloutier, Ph.D.


Decentralized wastewater treatment exists primarily in suburban and rural areas where centralized treatment is not an option. Traditional on-site treatment systems usually include the use of a septic tank and a drain field. This orthodox method works well when implemented into environments that are accommodating for the infiltration of effluents, and thus allowing for soil treatment. Unfortunately, there are some circumstances that prevent traditional systems from working such as impermeable soil conditions. The Wastewater Treatment System analyzed in this thesis was created to overcome such inhospitable environments. More specifically, this system is catered towards the rural residences of The Alabama Black Belt.

The Black Belt region of Alabama has Blackland Prairie soil that does not allow percolation of effluent wastewater. The wastewater treatment system operates outside the constraints of conventional on-site treatment systems by eliminating the need for permeable soil. Treatment is carried out through the use of three subsystems: a septic tank, modified lateral flow sand filter, and a modified constructed wetland. A scale model system was designed, constructed, and tested by the University of South Alabama. Parameters were tested from each subsystem and the percent reduction was analyzed. The overall percent reduction for each parameter is as follows: Nitrate: -39%, Ammonia: -1%, Total Nitrogen: 52%, Chemical Oxygen Demand (COD): 93%, Total Phosphorus: 74%, Biochemical Oxygen Demand (BOD): 96%.