Method for rapidly determining COD (chemical oxygen demand) of sewage and tester thereof

Abstract

The invention discloses a method for rapidly determining the COD of sewage and a tester thereof. The method comprises the following steps that: a sample is heated to be digested by oil which is 170 DEG C to 180 DEG C, a calculation formula is then utilized to work out the chemical oxygen demand of a water body, the tester is built, and under different COD concentrations, corresponding potassium dichromate and ferrisulphas are prepared in order to rapidly determine the COD. The invention has the advantages of environment-friendliness, mass determination, high COD determination accuracy, wide measuring range, short time and easiness in operation, and can be used for rapidly testing the COD in municipal sewage and industrial sewage samples.

Description

technical field [0001] The invention relates to an economical, convenient and rapid determination method of chemical oxygen demand (COD) in sewage / waste water and a detection device thereof. Background technique [0002] At home and abroad, it is generally believed that the chemical oxygen demand (Chemical Oxygen Demand, COD) of sewage / wastewater can be used to characterize the degree of water pollution. Salt Method" and the international standard ISO6060 "Determination of Chemical Oxygen Demand in Water Quality" as representatives, this method has high oxidation rate, good reproducibility, accuracy and reliability, and has become a classic standard method generally recognized by the international community. The basic measurement principle is to use potassium dichromate, sulfuric acid, and silver sulfate to digest organic matter under heating conditions, and then titrate the remaining potassium dichromate according to a certain concentration of ferrous ammonium sulfate, so a...

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Problems solved by technology

However, the traditional standard COD determination method has the disadvantages of large consumption of concentrated sulfuric acid, long reflux time, complicated operation, inconvenient operation, and difficulty in rapid determination in large quantities.

[0003] Therefore, many scholars have carried out a lot of exploration on the improvement of the COD determination method, for example, in the 201010234952.1 patent, the use of TiO 2 A photocatalytic device is used to digest organic matter, so as to achieve the purpose of quickly measuring COD, but the catalyst is easy to lose activity, the catalytic digestion effect is unstable, and it is easy to cause measurement deviation; Invention Patent 200710011688.3 reports an electrochemical method for measuring the chemical oxygen demand of water The method is to place the working electrode, the counter electrode and the reference electrode in the electrolyte solution sodium sulfate or sodium nitrate solution, control the constant potential, and measure the chemical oxygen demand value of the water sample by measuring the response current generated by the oxidation of organic matter; Patent 200910189911.2 reported a COD rapid determination device based on BDD electrodes; 200910025695.8 the present invention disclosed the preparation method of attapulgite clay catalyst and the method for measuring COD of the catalyst; patent 200910049082.8 also reported a prefabricated reagent for rapid determination of COD in water The preparation method and application of COD, by preparing prefabricated reagents with different concentrations of COD, can replace HACH reagents for the determination of COD in various water bodies, reducing the analysis cost, and some people have used microwaves to digest samples, which can digest 25 samples at the same time , but it needs to configure prefabricated reagents, the pretreatment is cumbersome, and it is also difficult to build a microwave digestion device

[0004] Therefore, in view of the currently reported rapid assay methods for COD assays, there are generally defects such as complex construction devices, difficult implementation, difficult operation, and high cost of mass assays.

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