LAUSR

Proper management is one of the most important environmental issues in wastewater treatment. Selecting the method of treatment depends on several factors, such as available facilities and technologies, quality and quantity of raw wastewater, outlet effluent standards, and budget. Because of low cost, design, construction, and easy operation of biological methods of wastewater treatment, they have been considered for a long time. Septic tank is one of the biological systems based on sedimentation and anaerobic biological treatment. The main problem associated with septic tanks is low efficiency. The present study aimed to determine the effect of hydraulic regime reform on performance of septic tanks in domestic wastewater treatment. This cross-sectional study was conducted on domestic wastewater in cement factory in Estahban during 7 months. In addition to evaluating the performance of septic tanks in domestic wastewater removal, some changes were made in its structure in order to modify hydraulic regime flow for increasing efficiency. After 4 months, as the period of habituation and stability of the reactor, physicochemical parameters such as biochemical oxygen demand, chemical oxygen demand, total suspended solid, total solid, total phosphorus, and total Kjeldahl nitrogen were evaluated in both inlet and outlet. The reactor’s performance in removal of the abovementioned parameters was 83%, 76%, 84%, 48%, 4.35%, and 2.40%, respectively. The control reactor’s efficiency for these parameters was 38% under the best condition.