TOTAL ORGANIC CARBON AS A PROCESS AND COMPLIANCE TOOL

The use of TOC (Total Organic Carbon) analysis as a process control and process compliance tool is finding increasing acceptance. Many NPDES permits call for BOD and COD reporting. These tests can take anywhere from a few hours to several days. This time limitation makes it difficult to maintain compliance or process control. By the time the test results are in, too much time has passed to be able to respond to incidents that may have occurred. In many plants, unexpected organic loading from industrial dischargers poses a difficult control challenge. In both these cases, online TOC offers hope to meet these challenges.TOC analyzers generally use either an ultraviolet lamp with an oxidizing agent or a catalyst –based combustion method to convert the organic carbon to carbon dioxide. The resulting carbon dioxide is measured in a NDIR detector against a reference. The resulting carbon dioxide is proportional to the Total organic carbon content. Therefore, the results are reports as mg/ml TOC.In water treatment, new regulations are dictating the measurement and reporting of TOC. In the industrial wastewater applications, TOC has been used for many years to determine the quality of in-plant outfalls and final plant effluents. In municipal wastewater, there is increasing interest in the use of TOC to control the aeration basins and find incoming organics. The continuing emergence of TOC as a process control tool allows on-line control to be achieved.