Efficiency of the Water Treatment Plants in Northern Salta (Argentina)

Abstract

The General San Martín Department, in northern Salta (Argentina), has a population of over 178,000
inhabitants. Its main water sources are two reservoirs, groundwater wells, and extraction points along
the Tartagal and Bermejo rivers. This study evaluated the condition and treatment efficiency of physical,
chemical, and biological parameters in the Itiyuro, Embarcación, and Tartagal water treatment plants
between June 2018 and January 2020, through monthly sampling at plant inlets and outlets. Physical
and chemical parameters were analyzed according to American Public Health Association (APHA),
standards, and phytoplankton counts were performed using the Utermöhl technique. Treatment
efficiency was calculated based on turbidity, color, and chemical oxygen demand (COD). Turbidity and color exceeded the limits established by the Argentine Food Code in outlet samples. Although turbidity removal occasionally exceeded 90%, it was still insufficient. COD reduction only reached a maximum of 48% at Itiyuro and was lower at the other WTPs. Biological treatment efficiency was low: none of the plants reduced total phytoplankton by more than 50%. These results suggest that the current treatment processes do not ensure the production of safe drinking water. The persistence of turbidity, wich is associated with potential biological contaminants, as well as the presence of cyanobacteria that can produce cyanotoxins, pose a significant health risk in the medium and long term.