Costs of Advanced Treatment in Water Reclamation

The additional removal of trace organic contaminants (TOrCs) provided by advanced water and wastewater treatment inevitably requires additional financial costs, which must be estimated to support utility planning and compare alternatives. This study presents conceptual-level (Class 4) capital and annual operations and maintenance (O&M) cost curve equations to aid evaluations of advanced treatment trains for water reuse. The cost curve equations are broadly applicable to the water reuse community, particularly those interested in ozone-based treatment trains. Unit processes include microfiltration or ultrafiltration membranes (MF/UF), nanofiltration or reverse osmosis membranes (NF/RO), ozone (with or without hydrogen peroxide, H₂O₂), ultraviolet (UV) treatment with H₂O₂ (UV/H₂O₂), and biological activated carbon (BAC); all cost curves are for a unit process and can be added together to obtain costs for a combined treatment train. The cost curves indicate that at all plant capacities (1 to 500 MGD), membrane treatment (e.g., MF or RO) represents the highest cost unit process, ozone the least, and BAC or UV/H₂O₂ fall in between. Additionally, the relationship between ozone dose and TOrC removal is discussed with a demonstration of how costs change with increasing ozone dose to achieve desired TOrC destruction.