ISO 23044:2020 PDF

Overview

ISO 23044:2020 provides international guidance for softening and desalination of industrial wastewater for reuse. The standard evaluates and compares six core treatment technologies - chemical precipitation, ion exchange, nanofiltration (NF), reverse osmosis (RO), electrodialysis (ED) and electrodeionization (EDI) - and describes how to characterise influent and effluent quality for reuse applications that have hardness and salinity limits. It focuses on industrial saline wastewater that has been pre-treated to remove most organics where necessary and is intended to support decisions for technology selection and process design.

Key topics and requirements

• Technologies covered: chemical precipitation, ion exchange, NF, RO, ED and EDI, with distinctions between softening (removal of Ca2+, Mg2+) and desalination (TDS reduction).
• Influent and effluent characterisation: guidance on monitoring TDS, hardness, alkalinity, SDI, turbidity, pH, temperature, TOC/COD, TSS and ionic species to assess suitability for specific processes.
• Pre‑treatment needs: recommendations to remove organics and particulate matter before membranes or ion-exchange systems to avoid fouling and resin contamination.
• Process selection considerations: technical and economic comparison based on influent quality, target product water quality, flowrate, site constraints and environmental requirements.
• Waste handling: attention to management of secondary wastes (e.g., ion exchange regeneration liquors, RO concentrate) and minimizing discharge of acidic/alkaline residues and sludges.
• Performance aspects: typical performance ranges and operational impacts (fouling, chlorine sensitivity, temperature and pH effects) for each technology are described to guide design and operation.

Applications

ISO 23044:2020 is focused on practical reuse scenarios where hardness and salinity matter, such as:

• Cooling circulating water
• Boiler feed water
• Production/process water
• Cleaning and rinse water
• Broader reuse categories include urban non-potable and environmental water, or producing high-purity or ultrapure reclaimed water when combined with polishing (e.g., RO + EDI).

Who should use this standard

• Water reuse and process engineers evaluating softening and desalination options
• Plant designers and operators in industries producing saline wastewater (oil & gas, chemicals, textiles, pharmaceuticals, food processing)
• Environmental managers and consultants planning wastewater reclamation schemes
• Equipment manufacturers and procurement teams comparing technologies for reuse applications

Related standards

• ISO 20670 - Water reuse: vocabulary (normative reference used by ISO 23044)
• Relevant ISO/IEC definitions referenced (e.g., ion exchange, reverse osmosis terminology)

Keywords: ISO 23044:2020, industrial wastewater softening, desalination for reuse, nanofiltration, reverse osmosis, ion exchange, electrodialysis, electrodeionization, chemical precipitation, TDS removal, influent quality, pre-treatment.