Prediction of the potential fates of future pharmaceutical compounds in indirect potable reuse systems Original Research Article

The potential fates in indirect potable reuse systems of 2179 pharmaceutical compounds that currently have been used or may be introduced within the next five years were estimated using a modified quantitative structure activity relationship model. Over 90% of the pharmaceutical compounds analyzed were estimated in this study as non-persistent in indirect potable reuse systems where the final removal barrier was sub-surface transport. The removal mechanisms of biodegradation and sorption were considered in assessing their persistence. The percentage of compounds produced by biotechnology was expected to increase from less than 20% to greater than 60% in the near future and this should result in a trend of decreasing persistence for future compounds. The potential rejection in indirect potable reuse systems that use reverse osmosis (RO) as the primary barrier was statistically evaluated. In order to evaluate RO performance, a multiple linear regression analysis was done using SPSS (ver. 17) and the main rejection mechanism for low molecular weight compounds was electrostatic repulsion. Treatment by RO is capable of removing greater than 95% of future compounds and would be expected to perform as efficiently as with currently used compounds.