Estimation of pathogen removal in an advanced water treatment facility using Monte Carlo simulation

Interest in water reuse for potable purposes has heightened the significanc e of evaluating the potential presence of microbial agents in treated water . Evaluating the public health risk from microbial agents in water after ad vanced water treatment (AWT) requires an estimate of the effectiveness and reliability of the treatment system in removing microbial agents. Indicator organisms such as total and fecal coliform do not provide sufficient basis to characterize the performance of the treatment system relative to the re moval of pathogenic organisms such as enteric viruses and parasitic agents. Seeding studies provide an alternative experimental approach. However, whe n treatment systems are challenged using more specific indicators for enter ic viruses, the results are often inconclusive because the organisms are re duced to non-detectable levels after the first few unit processes. In this study we provide a :mathematical approach for estimating the effectiveness of the entire treatment train with respect to removal and/or inactivation o f microbial agents. These estimates are insightful since standard monitorin g of final effluent consistently yielded non-detectable results. (C) 1999 I AWQ Published by Elsevier Science Ltd. All rights reserved.