The 9210 online total organic carbon (TOC) analyzer from OI Analytical, a Xylem brand, is designed for routine monitoring and regulatory compliance in process water streams. The analyzer provides real-time data and visibility of natural organic matter (NOM) during the treatment process, enabling operators to adjust and control the coagulation, flocculation and disinfection steps.
“The development of this analyzer grew out of a project with NASA,” says John Welsh, product line manager for OI Analytical. “It’s used on the International Space Station as a means to monitor the water they reclaim and use to produce potable water.
The 9210p measures TOC using the heated persulfate wet oxidation technique, developed by Dr. Alan D. Fredericks, a research scientist in the Department of Oceanography at Texas A&M University, now with OI Analytical. Most organic compounds dissolved in water can be oxidized by heated sodium persulfate. OI Analytical introduced the first commercial TOC instrument based on the technique in 1972. The technique is approved for SDWA regulatory compliance monitoring using USEPA-approved methods 415.3 and SM 5310C.
Two instruments are available for TOC analysis of surface water, groundwater and finished drinking water: the Aurora 1030W laboratory TOC analyzer and the 9210p online TOC analyzer. A comparative study demonstrated that the 9210p online analyzer obtains data that is comparable and consistent with grab samples from a 1030W laboratory analyzer.
“The advantage of an online system is quicker analysis,” Welsh says. “There’s virtually no lag time between collecting the sample, preserving the sample, transporting the sample to a laboratory, analyzing the sample and getting the data.
“Sometimes with online applications you’re limited in amount of space you have,” he says. The 9210p analyzer is 19 inches high by 12.25 inches wide, 12.25 inches deep and weighs 24 pounds. Measurement ranges from 5 to 250 ppm carbon.
“Most TOC online analyzers also require a fixed gas of some sort,” Welsh says. “Our analyzer produces its own — it’s built into the instrument.”
In operation, samples are drawn into the 9210p at user-defined time intervals from a fill and spill sampling system. Phosphoric acid is introduced into the syringe to sparge and remove the inorganic carbon (TIC) content. The TIC-free sample is transferred into the reaction chamber and oxidized at a programmed temperature up to 212 degrees F (100 degrees C). Organic compounds are oxidized and converted to CO2, which is measured by a solid state, non-dispersive infrared (SSNDIR) detector to calculate TOC content. Results for each sample are shown on the touch-screen display and can be output to a SCADA system, PC via Ethernet connection, relay/alarm closure or as a 4-20mA analog signal. 800/653-1711; www.oico.com.
