Performance of Lagoon Wastewater Treatment System in Sapecho, Bolivia

The performance of an integrated up-flow anaerobic sludge blanket (UASB) reactor and lagoon wastewater treatment system in the community of Sapecho, Bolivia has been analyzed over a 2-year period. The wastewater treatment system has a design capacity of 0.04 MGD and serves a small rural community with a population of 1,039 people. The treatment system consists of a grit chamber, an upflow anaerobic sludge blanket (UASB) reactor, biosolids drying bed, and two maturation ponds and The treatment system was evaluated its effectiveness in removing total suspended solids (TSS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrogen, phosphorus and total coliforms. Our results show the overall removal efficiency of the system was 97% TSS, 97% BOD, 91% COD, 61% total nitrogen, 7% total phosphorus, and 99.9% total coliforms. Most of influent removal occurred between the grit chamber and the UASB reactor with 90% TSS, 74-86% BOD, 79-83% COD, 30-39% total nitrogen, and 96% total coliforms. A further 7.7% TSS, 11.4% BOD, 8.1% COD, 22.4% total nitrogen, 11.2% total phosphorus, and 3.8% total coliforms from the influent were removed by the maturation lagoons.An average methane composition of 66% was produced by the UASB reactor. Further it was estimated that an average of 9.33 x 103 kJ/day (28 gigajoule per month, 336 gigajoule per year), of energy was produced by the UASB reactor.Our life cycle cost results show the intergrated wastewater treatment system costs a total of 99,000 over the 20-year design life. About 82,400 or 83% of the life cycle cost over the 20-year life is attributed to initial capital cost. The other 16,600 (0.02/GPD) of the life cycle cost over the 20-year design life is attributed to maintenance of the system.