A stepped dosing method and device for chemical oxygen demand detection

Abstract

The invention discloses a stepped dosing method and device for chemical oxygen demand detection in the field of water quality detection. A digestion module is arranged over an inflow and outflow main valve, the lower end of the digestion module is connected to the upper inflow and outflow port of the inflow and outflow main valve through a digestion tube inflow and outflow port, and the lower inflow and outflow port of the inflow and outflow main valve is connected to the upper inflow and outflow portion of a sample-inputting peristaltic pump through a duct; and the digestion module comprises a digestion tube, a heating wire, an optical receiver, and a light source emitter. Stepped stage-by-stage dosing reaction is adopted, a rectangular coordinate system is established with a COD (chemical oxygen demand) value detected at each stage as x and a potassium dichromate agent volume value as y to carry out dynamic curve fitting, whether agent is added or not next time and the dosage of the agent are determined according to the magnitude of dynamic curve potential, so that dosing is dynamically controlled, consequently, the objective of controlling the dosage of potassium dichromate as an oxidant is achieved, the oxidant is prevented from being excessively added to waste the agent, the usage of the agent is effectively reduced, and thereby the water quality COD detection cost is reduced.

Description

technical field [0001] The invention relates to the field of water quality detection, in particular to a chemical oxygen demand (COD) detection in a water body, especially a dosing method and device for detection of the chemical oxygen demand. Background technique [0002] Water quality testing can timely, accurately and comprehensively reflect the quality of water environment and the status quo of pollution sources. In water quality monitoring, chemical oxygen demand is the content of oxygen consumed by organic matter in water, and is one of the important indicators to evaluate the degree of water body pollution by organic matter. At present, the determination methods of chemical oxygen demand include potassium dichromate method, potassium permanganate method, potassium dichromate colorimetric method, rapid digestion method, electrochemical method, continuous flow analysis method, etc. For the detection standard of the potassium dichromate method, refer to GB11914-89. The p...

AI Technical Summary

Problems solved by technology

Compared with the potassium dichromate method, the spectrophotometric method replaces the titration link with the colorimetric method, which reduces the detection cost of the analysis link and improves the work efficiency of the analysis link; Dosing is a one-time addition of excessive medicament for digestion reaction, so the amount of potassium dichromate and silver sulfate has not been reduced

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