Treatment Performance of Wastewater Lagoons in South Yungas Province of Bolivia

The operation of wastewater lagoons systems located in the South Yungas Province of Bolivia has been analyzed over a 2-year period. Facultative and maturation lagoons were evaluated for their performance in removing total suspended solids (TSS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrogen, phosphorus, and coliforms. Facultative lagoons operating in San Antonio were found to remove approximately 74% total suspended solids, 70–89% BOD, 62–85% COD, 53% nitrogen, 52% phosphorus and 97.8–99.9% coliforms. Maturation ponds were found to remove 74–93% total suspended solids, 22–62% BOD, 10–95% COD, 3% nitrogen, 20–95% phosphorus and 77.4–99.96% coliforms. Results from the 2-year study indicate that these wastewater treatment systems are currently performing as expected; however regular maintenance, specifically removing algae every (2 weeks) is required. The removal percentages of the treatment systems (comparing influent to effluent) ranged from 74–97% TSS, 78–98% BOD, 70–99.7% COD, 58–77% nitrogen, 62–99.9% phosphorus, and 99.99% coliforms.