Overview
ISO 16075-5:2021 - Guidelines for treated wastewater use for irrigation projects, Part 5 - provides practical guidance on disinfection and equivalent treatments of treated wastewater (TWW) intended for irrigation. The standard explains the principles, technologies and monitoring approaches required to achieve effective pathogen inactivation or removal while minimizing environmental impacts. It covers disinfection applied at different points in the TWW use system (in the wastewater treatment plant, within distribution, and at point-of-use).
Key technical topics and requirements
- Pathogens and reduction mechanisms
- Types and occurrence of pathogens in wastewater and how different treatment stages reduce microbial risk.
- Chemical disinfection
- Chlorine/bromine chemistry, interactions (e.g., with ammonia), residual definitions, breakpoint reactions and CT considerations.
- Ozonation chemistry, direct and indirect reactions, system configuration and monitoring.
- Environmental impacts and mitigation strategies for chemical biocides.
- Physical disinfection and equivalent treatments
- UV disinfection: lamp types,-ballasts, sensors (UV intensity and transmittance), disinfection chambers, validation methods (including biodosimetry/RED), cleaning and maintenance.
- Membrane filtration: micro-, ultra- and nanofiltration principles, pathogen removal performance, fouling, operational monitoring and maintenance.
- Advanced Oxidation Processes (AOPs) and other equivalent treatments referenced as options for organic and microbial control.
- Design, operation and monitoring
- Establishment of effective doses, system design guidance, possible interferences, validation and performance monitoring methods.
- Comparative assessment of advantages/disadvantages, lifecycle and environmental effects.
- Terminology and definitions
- Uses ISO 20670 vocabulary and defines operational terms (e.g., RED, fouling, pore size).
Practical applications and who uses this standard
ISO 16075-5:2021 is aimed at professionals involved in wastewater reuse for irrigation, including:
- Water reuse planners, irrigation project designers and agricultural engineers
- Wastewater treatment plant designers and operators
- Environmental and public health regulators and auditors
- Consultancy firms assessing disinfection options and environmental impacts
- Procurement/specification teams selecting disinfection equipment and monitoring regimes
Practical uses include selecting appropriate disinfection technologies (chlorination, ozonation, UV, membranes), defining monitoring and validation protocols, designing systems to meet microbial safety goals, and minimizing downstream environmental impacts.
Related standards
- ISO 16075 series - other parts of the guidelines for treated wastewater use for irrigation projects (Part 5 is the disinfection-focused part)
- ISO 20670 - Water reuse - Vocabulary (normative reference used by this document)
Keywords: ISO 16075-5:2021, treated wastewater, TWW disinfection, wastewater reuse, irrigation, UV disinfection, chlorination, ozonation, membrane filtration, pathogen removal, monitoring, water reuse standards.