Application of the Iber Two-Dimensional Model to Recover the Water Quality in the Lurín River

Abstract

The Lurín River is one of the main sources of water for the city of Lima. However, the discharge of domestic wastewater, the presence of dumps, and long periods of drought cause the deterioration of the water resource. In this study, DO, BOD5, E. coli, T, EC, TSS, U, and h were monitored at 13 monitoring points spread over 20 km of river influence. This information was used to calibrate the parameters of Kdbo, Kaire, Kdos, and Kdec in the Iber two-dimensional numerical model, obtaining values of 0.55 d−1, [4.84 d−1–80.65 d−1], 10 g O2 m−2d−1, and [1.49 d−1–15.42 d−1], respectively, with efficiencies ranging from “very good” to “satisfactory”. In the hydraulic model, a discretization of the channel, banks, and plains of 3, 5, and 7 m, respectively, was considered, resulting in a computational calculation time of 4 days in each simulation. The greatest contamination occurs in July at km 5 + 400 up to the Pan-American bridge. Therefore, it is proposed to recover the river by optimizing the San Bartolo Wastewater Treatment Plant (WWTP) and a new WWTP in Pachacámac to avoid diffuse contamination, with discharge flows of 0.980 m3s−1 and 0.373 m3s−1, respectively, and 4 mg L−1, 15 mg L−1 and 1000 NMP/100 mL for DO, BOD5, and E. coli, respectively.