TOC, COD & SAC Analyzers

TOC, COD & SAC Analyzers

TOC, COD, and SAC analyzers quantify organic load in water and wastewater by measuring total organic carbon, chemical oxygen demand, and spectral absorption coefficient. These sum parameters are used to assess surface water, municipal wastewater, and industrial wastewater quality, with outlet measurements supporting regulatory compliance and inlet measurements supporting process protection by identifying load peaks and enabling improved control responses.

Product selection typically begins with the measurement objective. TOC and COD analyzers provide “true” values where precise analysis is required - for compliance with authority limits, assessment of treatment capacity, or billing of industrial dischargers under polluter-pays frameworks. SAC probes are positioned for surface water and river monitoring and for cost-efficient estimation of COD/TOC equivalents in municipal wastewater when conditions are relatively stable and large fluctuations are not expected.

Multiple measurement principles are used. COD is commonly measured with colorimetric digestion (dichromate method): the sample is heated with reagents, a color change occurs proportional to oxidizable content, and photometric measurement with preset absorption curves yields COD. TOC analysis can use high-temperature catalytic combustion with subsequent NDIR detection of produced CO₂, including sample acidification/stripping and filtration steps. SAC measurement uses UV absorbance at 254 nm with a reference wavelength (e.g., 550 nm) to compute a ratio-based signal converted to SAC via calibration curves.

Benefits include coverage from fast inline measurement to regulation-compliant online analysis, supported by availability of standards and reagents supplied with MSDS documentation. Sample conditioning systems support representative, homogeneous samples for TOC monitoring, while COD analysis integration can use a Y-strainer approach to deliver samples with appropriate solids content. Optical SAC sensors avoid reagents entirely and provide direct inline measurement with diverse ranges for applications from clean water through industrial wastewater.

Integration strategies often pair sum-parameter measurement with additional online parameters to interpret load changes and treatment response. Liquiline System CA80 analyzers can connect additional Memosens sensors, enabling broader process context without deploying separate measuring devices at each point. When designed as a coherent monitoring layer, TOC/COD/SAC signals support earlier intervention, improved documentation, and tighter alignment between influent dynamics and operational response.

At Eastern Controls, We are proud to be the exclusive authorized sales and service representative for Endress+Hauser.