TOC and TN Analysis in Pulp and Paper Process Effluents
The pulp and paper industry generates large volumes of wastewater or effluents that need to be treated before they can be reused or released into natural waterways. According to the European Industrial Emissions Directive (IED) Best Available Techniques (BAT) have to be implemented within the EU for direct wastewater discharges from pulp, paper and card production). The BAT reference document (BREF) indicates that among other parameters, TOC (total organic carbon) and TNb (total bound nitrogen) are of growing importance. They need to be monitored on a daily or weekly basis. Furthermore, for economic and environmental reasons a preference for the parameter TOC instead of COD is given as it does not require the use of highly toxic compounds like dichromate (Cr VI) and mercury.
TOC/TNb Determination in Municipal Sewage Plants
In wastewater treatment plants, the organic and nitrogen load have to be measured in the untreated inflow, the pretreated effluent, and the final effluent after the completed treatment process. In many cases, the chemical oxygen demand (COD) and TN contents are measured with separate methods. This is a labor- and time-consuming process often associated with the formation of chromium-VI-contaminated waste. Through correlation studies, an empirical conversion factor for TOC to COD conversion can be established. Hence, a fully automated analytical process for TOC/ TNb determination according to EN 1484 and EN 12260 can be applied to save resources and time.
