Development of a Simple and Quick COD Measuring Method with a Microwave
Yutaka ARAKAWA,1 Keiko KURITA,1 Hirokazu SUGIMORI,1
Yasuhiro TAKUMA,1 Eri ANDO,1 and Akifumi YAMADA2
1Tokyo Metropolitan Industrial Technology Research Institute
(3-13-10 Nishigaoka，Kita-ku，Tokyo 115-8586)
2Nagaoka University of Technology，Techno-Incubation Center
(1603-1 Kamitomioka，Nagaoka，Niigata 940-2188)
(Received July 14, 2011; Accepted August 12, 2011)
Abstract
A simple and quick COD (Chemical Oxygen Demand) measuring method which reduces environmental impact and analysis costs was developed. The COD - sewer alkalinity test was chosen as a method which does not use an expensive silver reagent or toxic substance. A commercial electric pipette was applied to a micro-titration operation required to make a 1/10 scale analysis. The microwave oven used to shorten the analysis time reduced the heating time from 30 to 5 minutes. The stirrer bar made from PTFE solved a bumping problem during heating, and the uneven heating problem was overcome through the design and manufacture of the exclusive vial rack. Furthermore, the reaction stop process was simplified by using a mixed reagent; 12.5 mM (mM = mol m-3) -sodium oxalate and sulfuric acid (1+2). The time required for the analysis was 1/5 shorter than that of the official method (CODMn), and the amounts of reagents consumed and waste fluid produced were 1/10 or less. The measurement reproducibility of this method was 5 % or less, and, compared with the official method, the correlation coefficient for varied organic matter was 0.9 or more.
Keywords:
COD, microwave oven, electronic pipette, vial rack
