treatment of domestic wastewater in shallow waste stabilization ponds for agricultural irrigation reuse

Waste stabilization ponds are a well established wastewater treatment system being considered by World Health Organization as one of the most appropriated technology for domestic wastewater when agricultural reuse is considered, especially in developing countries. This study was performed in a series of pilot-scale stabilization ponds, being one facultative and three maturation ponds, with depths varying from 0.44 to 0.57 m. The substrate to be treated was composed of a mixture of domestic wastewater and previously anaerobicaly treated leachate. The experimental system was monitored in two different phases, in which the hydraulic retention times were 15 (phase 1) and 10 days (phase 2). Termotolerant coliform removal efficiencies were 3.8 log10 units in both phases while organic matter (BOD5) removal was 87 and 68% for phases 1 and 2, respectively.