Full-scale maturation ponds working below a latitude of 43°S in a semiarid area: seasonal performance and removal mechanisms

Abstract

Stabilisation ponds are the most frequently used wastewater treatment technology in Argentina. This study focuses on the performance of two maturation ponds (MPs) that are part of the full-scale sewage treatment system of Puerto Madryn. Seventy-seven shots of surface water were analysed for organic matter, inorganic nitrogen, phytoplankton dynamics and bacterial removal. The system presented a clear evolution with respect to oxygenation and phytoplankton development. The treated wastewater reached values above 8 mg-O2/L, an important organic matter removal, and this was accompanied by a strong increase in pH. NH4 + removal and oxidation, was active even during winter in the MPs, with average concentrations below 10 mg - NH4 + /L. Bacteriological removal resulted in a liquid that approached the WHO recommendations for unrestricted irrigation. These results show that is possible to generate treated wastewater in stabilisation ponds working in a semiarid and temperate region, with bacterial content and conductivity suitable for irrigation.