Scaling Water Reuse: New State Regulatory Guides And What They Mean For Treatment Design

Water reuse in the United States is rapidly moving from pilot projects to a central component of long-term water supply planning. In response, the WaterReuse Association has launched a state regulatory guide initiative to help harmonize reuse regulations, providing science-based templates for states to adapt locally. This shift signals to utilities and engineers that reuse systems must be designed not just for current rules, but for evolving standards.

Ozone and ozone-based advanced oxidation technologies are increasingly essential to meet these regulatory expectations. Multi-barrier treatment requirements emphasize pathogen reduction, where ozone delivers rapid inactivation of viruses, bacteria, and protozoa with predictable CT-based performance. Regulations also target trace organics, including pharmaceuticals and industrial compounds; ozone alone or in combination with hydrogen peroxide or UV generates hydroxyl radicals capable of oxidizing even resistant compounds. Additionally, pre-oxidation with ozone reduces natural organic matter, improving downstream biological filtration and limiting disinfection by-product formation.

Modern reuse treatment trains must be flexible, accommodating seasonal water quality variation and regulatory changes. Modular ozone generators with real-time dose control enable adjustments without major reconstruction, while instrumentation supports continuous verification of ORP, residual ozone, and flow-weighted CT. A regulatory-ready system may include tertiary filtration, ozone contactors, ozone-based AOP, BAC filtration, UV disinfection, and stabilization/blending, with ozone providing multiple compliance functions simultaneously.

As state guidance expands, utilities that integrate robust ozone-based treatment gain quantifiable disinfection, broad-spectrum contaminant control, and adaptability—building reuse systems that are technically sound today and future-proofed for tomorrow.