Online Monitoring of the COD* Parameter of Surface Active Agents

Online Monitoring of Surfactants by COD* Parameter In recent years, pollution from domestic and industrial wastewater and the treatment of such pollution have become increasingly important. Detergents play a significant role among the pollutants threatening water resources. Detergents, commonly found in cleaning products, have been in use since the early 1900s. Detergents contain surfactants, bleaching agents and certain auxiliary substances. Surfactants are the most effective component in detergents that enable the cleaning process. These substances are compounds that allow materials that are incompatible with water and therefore cannot be removed and cleaned with water to be dissolved and removed with water. The increased use of surfactants causes pollution in surface waters. Today, various methods are applied to treat surfactants (SAM), and their discharge control is managed through regulations. These substances, which can be treated only to a limited extent by conventional treatment methods, also show an inhibitory effect on bacteria found in treatment sludge (Akın, 2009). In activated sludge treatment systems and in the receiving water bodies into which they are discharged, biologically partly and/or slowly degradable SAM accumulate in biological treatment sludges and/or in receiving environment sediments (Ahel and Giger, 1993). Accumulated SAM in the receiving environment causes biotoxic effects. It mixes into water and soil and re-enters the life cycle through plants. In recent years, in treatability studies conducted for SAM, it has been determined that during advanced oxidation process (AOP) applications, the toxic effects of intermediate products decrease and their biological degradability increases (Poole et al., 2004). During the removal of SAM by AOP, the organic content of surfactants can be monitored through the measurement of COD and TOC** parameters. In the chemical industry, in auxiliary facilities, the efficiency of the treatment process can be monitored for SAM by performing either rapid and instant measurements (COD probe CAS51D, CAS80E) or laboratory precision measurements (CA80COD COD analyzer). Additionally, before being supplied to the treatment facility, the SAM value can be monitored through the COD parameter in balancing tanks, if available. This makes it possible to perform instant and precise measurements in accordance with the relevant sector table. Protection of the environment, continuity of product quality, process optimization and safety explain why the importance of liquid analysis is continuously increasing. Affordable clean water provision is one of the most important agenda items for both today and tomorrow. Water analysis is a subject we address specially across all industries, from food to chemicals, from wastewater to energy. A comprehensive water quality monitoring program requires a product portfolio containing all relevant parameters. As Endress Hauser, we fulfill this responsibility by offering a portfolio that meets all needs. The CAS80COD COD Analyzer, which can be used for monitoring the organic content of SAM, provides precise online measurement at all critical control points such as treatment facility inlet and outlet lines as well as aeration tanks. Its features such as automatic calibration, self-cleaning and optimization of reagent quantity help reduce your maintenance costs. The devices also perform self-diagnosis and control, automatically creating support records in the system, so Endress Hauser detects this condition before users even realize there is a malfunction in the device. An additional Memosens sensor connection allows you to monitor different parameters such as pH on the same analyzer screen that you want to track at the facility. The CA80COD, which can provide results in parallel with the laboratory through colorimetric measurement principle, provides the most reliable measurement for understanding whether you are meeting the discharge values you are responsible for at the facility outlet. • Wide measurement range up to 0–20,000 mg/l O2. • Results in parallel with laboratory by colorimetric measurement method. • Adjustable measurement time (30 min.–24 hours). • Sampling capability according to pH, conductivity and other parameters with Memosens technology. Another measurement principle that provides instant measurement is the spectro/photometric method. CAS51D and CAS80E are examples of devices operating on this principle. Organic compounds contained in SAM are water-soluble and generally absorb UV light. For this reason, UV absorption is used to determine dissolved organic matter in water. The advantages it offers compared to analyzers are the absence of sample preparation requirements and chemical consumption. They come ready to use with factory calibration, and maintenance intervals are extended thanks to air purging. They can also be calibrated up to 5 points and have digital communication thanks to Memosens technology. Due to digital communication, sensors are not affected by water and humidity, they retain calibration data in their memory and are automatically recognized by the transmitter. As Endress Hauser, we aim to enable you to operate your facility at maximum capacity through the detection and monitoring of surfactants in water via the COD parameter, helping you ensure water safety and process efficiency. *: Chemical Oxygen Demand **: Total Organic Carbon