Membrane septic tank performance analysis (Uruguay)
Septic tank systems are some of the most employed decentralized primary treatment systems globally which only partially treats the influent wastewater. This study aims to evaluate the performance of a membrane filtration septic tank system in terms of organic matter, nutrient and pathogen removal, hence improving the quality of the septic tank’s effluent; and evaluate resource recovery and reuse potential of the permeate. In addition, the performance of the membrane will be assessed. It was proven that the membrane filtration system was effective at removing on average 88%, 62% and 86% of COD, TP, and NH4 respectively from the septic tank effluents and 100% removal of E. coli and total suspended solids. Total nitrogen was however not removed as the system was not designed to do so. In addition, the membrane filtration mainly experienced reversible fouling from organic foulants present in the wastewater. A lab scaled septic tank with membrane filtration, for treating the septic tank’s effluent was used. The performance of the system was analysed by assessing the level of nutrients, pathogens and organic content within each section of the system. Transmembrane pressure and permeability were used to assess the membrane’s performance. Septic tank fitted with membrane filtration demonstrates promising potential for permeate reuse mainly for irrigational purposes. The system could be further analysed to examine more potential resource recovery possibilities by testing both liquid and sludge phases of the septic wastewater throughout the system compartments, and performing complete mass balance.
