Proceedings

The high construction, operation, and maintenance costs for a centralized conventional
wastewater collection and treatment system represent an obstacle for the Egyptian
government in the installment of such a system in rural areas. Due to operational simplicity
and low cost of the system, a new concept for a modified septic tank named Upflow Septic
Tank/Anaerobic Baffled Reactor (USBR) was used in the previous study conducted at Iowa
State University. Based on the results obtained in the previous phases, a full-scale
installation was designed and constructed in Abo Halifa village in Egypt to observe the system
performance through the whole year.

During almost one year of continuous operation and monitoring, this system has very
satisfactory removal results. The average results were 84% for the total chemical oxygen
demand (COD) removal, 81% for the total biochemical oxygen demand (BOD) removal, and
89% for the suspended solids (SS) removal. Also, almost all the treated effluent results for
the BOD, COD, and TSS had values less than that required by the Egyptian standard (law 48,
year 1982) for disposing this effluent water into an agricultural drain.

The experiment proved that the second compartment (Anaerobic Baffled Reactor) considered
main treatment unit in removing the pollutants in the start-up period and at very early steady
state stage. Also, it was observed that the system performance is slightly influenced by the
temperature. The sewage flow variations (liter/ capita/ day) during the year were detected
into this experiment and the results were compared with Goodrich Formula for the ratio
between the maximum weekly and monthly flows and the average flow to see the applicability
of this equation with the flow variation in the rural Egypt.

KEY WORDS
Anaerobic Baffled Reactor; Modified septic tank; up-flow septic tank; rural Egypt