ISO 23138:2024

Overview

ISO 23138:2024 - Biological equipment for treating air and other gases - General requirements specifies the technology, terminology and application requirements for biological exhaust‑air purification systems. The standard describes process principles (Clause 4), defines key terms (biofilter, biotrickling filter, bioscrubber, waste gas, elimination capacity, residence time, etc.), and presents the different technique variants and relevant requirements for their practical use.

Keywords: ISO 23138:2024, biological exhaust air purification, biofilter, biotrickling filter, bioscrubber, VOC treatment, waste gas cleaning, air purification standards.

Key topics and technical requirements

• Process principles (Clause 4):
  • Two‑step pollutant removal: physical absorption/mass transfer followed by biochemical conversion by microorganisms.
  • Mass transfer mechanisms (gas–liquid interface, absorption, diffusion) and reaction at microbial cells.
  • Requirements for successful biodegradation: good biodegradability, water solubility, suitable temperature range (mesophilic), and absence of toxic compounds.
• Technique classification and design parameters:
  • Descriptions and distinctions among biofilters, biotrickling filters, and bioscrubbers.
  • Design considerations such as empty bed residence time, pressure drop, support media, moisture content and water retention capacity.
• Component and operational requirements:
  • Filter media characteristics, nutrient and nutrient‑salt management (C:N:P considerations), moisture reservoirs, irrigation and clogging control.
  • Regeneration, replacement and safe disposal of filter media.
• Performance metrics and testing (Clause 6):
  • Definitions of efficiency (removal efficiency), elimination capacity and pollutant concentration metrics.
  • Guidance on measurement and testing to verify performance.
• Terminology and references: clear definitions to ensure consistent specification, procurement and commissioning.

Practical applications and users

ISO 23138:2024 is intended for organizations and professionals involved in design, selection, installation, operation and regulation of biological air‑treatment systems:

• Environmental and process engineers designing biofilters, biotrickling filters and bioscrubbers.
• Manufacturers of biological air‑cleaning equipment and media suppliers.
• Plant operators and maintenance teams at wastewater treatment plants, composting and waste treatment facilities, anaerobic digestion plants, industrial sites and paint shops.
• Environmental consultants and authorities assessing emissions control strategies for odours and volatile organic compounds (VOC). Practical use cases include odour control (H2S, NH3, sulfides), VOC removal from industrial exhausts and low‑energy, near‑CO‑neutral air cleaning solutions.

Related standards

• The document builds on established German VDI guidance (VDI 3477, VDI 3478 parts) and references ISO terminology resources (e.g., ISO Online Browsing Platform). See ISO/TC 142 (Cleaning equipment for air and other gases) for committee context.

For procurement or compliance, reference ISO 23138:2024 when specifying biological exhaust‑air treatment systems to ensure consistent terminology, validated design parameters and documented testing methods.