TOC, COD & SAC Analyzers

TOC, COD & SAC Analyzers

TOC (Total Organic Carbon), COD (Chemical Oxygen Demand), and SAC (Spectral Absorption Coefficient) analyzers quantify organic loading using different principles and time scales. TOC analyzers typically oxidize organic carbon to CO₂ and measure the result, COD analyzers estimate oxygen demand (often via oxidation methods or correlations), and SAC uses UV absorbance as a fast surrogate for organic content. These instruments may be in-line, at-line, or on a conditioned sample stream, with transmitters providing outputs, diagnostics, and data handling.

The benefit is rapid visibility into organic load changes that affect treatment capacity, product quality, and compliance. Continuous TOC/COD/SAC monitoring supports early detection of spills, process leaks, and washdown events, enabling quicker containment and corrective action. These measurements also help optimize chemical and energy use by matching treatment intensity to actual load rather than operating conservatively at all times.

Typical applications include wastewater influent monitoring, industrial pretreatment, and effluent verification for regulated discharge. In drinking water and reuse, organic monitoring supports treatment performance tracking and helps manage precursor levels tied to disinfection byproducts. In manufacturing, TOC is often used to confirm cleanliness and contamination control in water systems, rinses, and critical utilities where low organic content is required.

Implementation details include choosing the right parameter for the control objective. SAC offers fast response with minimal consumables but is a correlation that can be influenced by matrix changes. TOC provides a more direct measure of organic carbon but may require more complex oxidation and maintenance. COD methods vary and may involve reagents or calibration models. Sample conditioning - filtration, pressure control, degassing, and temperature stabilization - often determines long-term reliability.

Operational performance improves with routine verification, drift tracking, and maintenance aligned to fouling and scaling tendencies. Diagnostics that monitor lamp intensity, oxidation efficiency, and baseline stability protect data integrity. When integrated with flow measurement, these analyzers enable load calculations (mass per time), supporting better capacity planning and process optimization. Reliable organic monitoring reduces risk, improves response time, and strengthens reporting confidence.

Forberg Smith, an exclusive authorized representative of sales and service for Endress+Hauser.