ISO 20468-3:2020

Overview

ISO 20468-3:2020 - "Guidelines for performance evaluation of treatment technologies for water reuse systems - Part 3: Ozone treatment technology" specifies accepted methods to evaluate the performance of ozone (ozonation) treatment in water reuse applications. Building on the generic framework in ISO 20468‑1, this part defines how to measure the typical parameters that indicate ozone system performance, the recommended system configuration, monitoring points, and safety/environmental considerations for water reuse systems using ozone.

Key topics and technical requirements

The standard focuses on practical, measurable aspects of ozone treatment technology:

• System configuration: Required components and layout

  • Feed gas supply unit (air or oxygen-fed)
  • Ozone generation unit (typically corona discharge)
  • Ozone contact unit (dissolution system, contactor)
  • Off‑gas ozone treatment (destruction and suction units)
  • Ozone measuring system (monitoring points for control and safety)

• Performance parameters and definitions (used for evaluation and reporting)

  • Generated ozone amount / concentration (gas-phase output)
  • Ozone dose, transferred ozone dose, ozone demand (mass per volume metrics)
  • Residual ozone concentration and off‑gas/exhaust residual ozone concentration
  • Ozone concentration monitoring at key points (see Annex C)

• Evaluation procedures and requirements

  • Functional requirements for measuring ozone transfer efficiency and disinfection/oxidation effects
  • Non‑functional requirements: performance characteristics, environmental and economic key factors, and safety requirements
  • Control and monitoring methods for ozone generation (Annex D) and recommended measurement points (Annex C)

• Informative annexes: Main treatment technologies and target constituents (Annex A), reuse water quality parameters (Annex B), monitoring and control guidance.

Practical applications

ISO 20468-3:2020 is intended for use in projects where ozone is employed to improve water quality for reuse, including:

• Tertiary treatment for municipal wastewater reuse (disinfection, color/odor removal)
• Industrial water reuse where oxidation of specific contaminants or micropollutant mitigation is required (noting high‑dose ozonation can target micropollutants)
• Combined treatment trains (pre‑treatment such as sand filtration; post‑treatment such as biological activated carbon or secondary disinfection)

Who should use this standard

• Water reuse technology manufacturers and ozone system suppliers
• Design and process engineers specifying ozonation systems
• Water utilities, plant operators, and consultants evaluating treatment performance
• Regulators and conformity assessors defining acceptance criteria for reuse schemes

Related standards

• ISO 20468-1 (General guidelines for performance evaluation of water reuse treatment technologies)
• ISO 20670 (Water reuse - Vocabulary)

For detailed measurement methods, monitoring point diagrams and control strategies consult the full ISO 20468-3:2020 document and related ISO 20468 series publications.