Benchtop Septic System for Effluent Treatment - A Laboratory Development

One in every five households in the United States of America operates a decentralized water treatment systems which is also know as septic system, which may contribute to pollutions in water bodies if not operated properly. For this research a 15.0-liter (3.97 gal.) laboratory benchtop septic system was designed, build, installed and operated at a temperature of 23.0°C (73.4°F) to investigate the remediation of municipal wastewater. A three-week start-up phase was used prior to operating the system with unfiltered wastewater collected from primary clarifier at a wastewater treatment. The operational test phase included an hydraulic retention rate of 5, 10 and 20 days which corresponds to 3000 ml/d, 1500 ml/d, and 750 ml/d respectively.

Based on the above results, the laboratory benchtop septic system minimum effluent values for the chemical oxygen demand are 18±1 mg/l, and 60±10 mg/l for the total solids content, and <5±1 mg/l for the total suspended solids. These values correspond to the published effluent concentration range of 30% to 80% of influent concentrations for septic tanks.

The results show, that the laboratory benchtop septic systems is able to reduce the chemical oxygen demand, total solids content, and total suspended solids content level of municipal wastewater and can be a valuable tool to access the performance of septic systems utilizing different wastewater influent types.