Electricity + Control May 2019

ANALYTICAL INSTRUMENTATION

ment stage in addition to facilities for neutralisa- tion, oil and grease removal (dissolved air flotation plants) and mixing and equalisation basins. In the case of indirect discharge, the wastewater treat- ment technology needed will depend on regula- tory requirements (including national and/or mu- nicipal codes and by-laws). As public wastewater treatment plants are often not designed for high loads, industrial wastewater – such as wastewa- ter produced in dairy processing – must be pre- treated via an in-house wastewater treatment fa- cility before it is discharged. Analytical measuring devices used in waste- water treatment typically cover: • pH measurement during neutralisation, using Endress+Hauser’s CPS11D digital pH sensor, for example • Oxygen measurement during sludge activa- tion, using COS61D or COS51D digital oxygen sensors • COD (chemical oxygen demand) measure- ment in the outlet of indirect dischargers, us- ing CA80COD or CAS51D digital nitrate or SAC (spectral absorption coefficient) sensors • Or TOC (total organic carbon) measurement, using CA72TOC. TOC, COD and SAC sensors are used to assess the organic load of industrial wastewater. All given examples of analytical instruments can be integrated into process automation systems. □

tion, water treatment can often be a multi-step pro- cess. A variety of filters, ion exchangers, reverse osmosis and other treatment techniques are used to remove impurities and create purified water. Typical analytical measuring devices used in such processes include Endress+Hauser’s: • Condumax CLS16D digital conductivity sensor, to monitor conductivity as a key parameter for assessing water purity • Ceragel CPS71D, a digital glass electrode spe- cifically for sterile and hygienic applications, to regulate the pH value setting • Turbimax CUS52D, a smart sensor for turbidity measurement, to check the efficiency of the filtration process.

Industrial wastewater

also needs to be treated in- house to meet national or local regulatory requirements before it is discharged.

Industrial wastewater treatment

Due to the volumes of wastewater produced and the variations in the load, particularly the pH value, wastewater needs to be treated in the case of both direct discharge and indirect discharge. Direct dischargers usually have a biological treat-

For more information, contact: Hennie Pretorius, Industry Manager: Water and Wastewater, Endress+Hauser hennie.pretorius@za.endress.com

Electricity + Control

MAY 2019

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