Estimating costs for nitrate and perchlorate treatment for small drinking water systems

When choosing a treatment technology for nitrate or perchlorate removal, drinking water utilities overwhelmingly choose ion exchange. However, of late, biological treatment and point-of-use systems have received a great deal of attention. This article utilizes several new U.S. Environmental Protection Agency models to estimate the cost of nitrate and perchlorate treatment for small drinking water systems. The analysis here shows that, when comparing the three technologies for a typical set of design choices and drinking water quality conditions, the least-cost option varies among the three depending on system size. This relationship varies with changes to the water quality and design factors such as, but not restricted to, influent nitrate and perchlorate concentrations, the choice of residual management options, and the presence of co-contaminants and competing ions.