Performance evaluation of package plant for treatment of single household domestic wastewater

This study was carried out to evaluate the performance of an anaerobic packaged onsite system as an alternative to septic tank for the rural and semi-urban areas of developing countries where centralized sewerage facilities are not available. Potential application was identified on the basis of pollutant removal efficiency. The average per-capita wastewater generation was found to be 140 L/person/day with maximum contribution from the kitchen. The average removal efficiency of the system for chemical oxygen demand (COD), biochemical oxygen demand, total suspended solids, total nitrogen, total phosphate and fecal coliform was 70.9 ± 11.8%, 68.7 ± 8.5%, 78.1 ± 4.7%, 20.2 ± 8.4%, 13.8 ± 3.7% and 86.5 ± 1.6%, respectively. Despite a satisfactory performance, the anaerobically-treated effluent did not meet the disposal standards and required subsequent post treatment. An electrochemical reactor with aluminium electrodes, at a potential difference of 12 V, showed appreciable potential for use in actual households as a post treatment option for further removal of the pathogens and COD. The treated domestic wastewater, with electrocoagulation as a post-treatment measure, was successfully reused for non-potable purposes. Therefore, the package system, in conjugation with electrocoagulation process, promises to be a highly efficient technology for the onsite treatment of domestic wastewater in developing countries while facilitating reuse of the treated effluent for various recreational purposes as well as a safe discharge.