The present invention relates to a method for determining the content of oxidizable organic compounds or substances which are dissolved, mixed or dispersed in a liquid and/or gaseous medium.

In order to determine, e.g. the amount of chemically oxidizable organic substances in water substantially two basically different methods are used. One method comprises titration of the sample solution with a standard solution consisting of potassium permanganate or potassium dichromate. Disadvantages of said methods of titration are that inorganic substances are oxidized at the same time, and that said methods require a certain time and not insignificant labor at a lab. Another method which was recently introduced consists of making a sample the object of a combustion reaction at higher temperatures, and measuring or determining the quantity of the combustion product CO2. The quantity of CO2 will, thus, provide an expression of the quantity of organic material of the sample. Disadvantages of the last mentioned method are that it requires very expensive apparatus, and an al1-automatic and continuous analysis is rendered difficult by the the combustion process proper.

It was an object of the present invention to provide a method which eliminates the above disadvantages connected with known technology. Furthermore, it was an object to achieve a simple and dependable method which may be automatized, and which permits continuous measuring and detection of organic material, e.g. in effluent from a factory, a municipal sewer, or the like.

According to the present invention the above objects are achieved by a method which is substantially characterized by the fact that a gaseous and/or liquid medium is contacted

with ozone gas, and that the carbon dioxide gas thus formed is subjected to measurements and calculations, so that its content of organic material may be determined. Further characterizing features of the method will appear from the following dependent claims.

The method is illustrated below with reference to a drawing figure by the aid of an example of an embodiment of the method.

The liquid to be examined flows through pipeline 1. A magnetic volumeter 2 measures the rate of liquid flow, and suitable measuring signals are transmitted to a microprocessor 4. From pipeline 1 a sample is taken through pipe branch 7 and magnet valve 8 to sample chamber 6. From an ozone container 9 ozone gas is added to sample chamber 6, via a conduit 10, and a magnet valve 11, sample chamber 6 now being filled with liquid through which finely dispersed ozone gas passes. "Cold combustion" of organic material will consequently occur in sample chamber 6, and the formed COs gas is conducted to a C02 measuring device 3 which will, in turn, transmit suitable signals to microprocessor 5, which will process the received measuring signals and will present them to the user in a suitable manner. In this manner, e.g. quantities of discharged organic material per hour may be read and recorded, upon a completed analysis of a removed and isolated volume.of liquid sample the sample chamber is ventilated by the aid of a ventilating device 12, and the sample chamber 6 is emptied of sample solution through discharge conduit 13 and magnet valve 14. 5 is the output signal unit which may be provided with telefax, alarm, etc. Microprocessor 4, inter alia, controls magnet valves and, consequently, the interval for analyses.