An assessment of an anaerobic filter packed with a low-cost material for treating domestic wastewater

The lack of available technologies that assembled both the technical and economical characteristics for domestic wastewater treatment is a major problem for rural communities. In response to this issue, a technical assessment of an up-flow anaerobic filter (UAF) was carried out in the laboratory to treat domestic wastewater. Tezontle, a volcanic rock, was used as the packing media and as the support for the biofilm. It was selected due to its abundance, low cost and high porosity. The UAF assessment was based on an experimental design of two variables, hydraulic retention time (HRT) and temperature, with three and four levels of operation, respectively. Each test at HRT of 12, 18 and 24h was carried out at temperatures of 20, 25, 30 and 35 degrees C. Methane production rates were 32.4, 110 and 191mL of CH4/g of chemical oxygen demand removed for HRT of 12, 18 and 24h, respectively, at a temperature of 35 degrees C. In order to reach a high removal of organic matter (higher than 80%) the optimum operational conditions for the UAF were HRT=24h and T=35 degrees C. The temperature was the determining factor for achieving the greatest removal efficiencies in the UAF.