Water quality on-line monitoring method and system

Abstract

The invention discloses a water quality online monitoring system which comprises a pump, a liquid storing unit, a reacting-detecting unit and a multi-pass direction selecting valve. The multi-pass direction selecting valve is provided with a sample introducing passage, a reagent passage, an analytical passage and a common passage communicating with the liquid storing unit; the reacting-detecting unit is composed of a light source, a reacting-detecting chamber, a detector and an analytical device; one end of the reacting-detecting chamber communicates with the analytical passage, and the other end is connected with a valve. The invention further discloses a water quality online detecting method. The monitoring system has the advantages of simple structure, high measurement accuracy and high response speed. Furthermore, the system can measure a plurality of parameters in a water sample, and can be widely applied to the online monitoring of water quality of various water sources, such as domestic sewage, industrial sewage, stream water, river water, etc.

Description

technical field [0001] The invention relates to water quality analysis, in particular to a water quality online monitoring method and system. Background technique [0002] In the wet chemical analysis methods of ammonia nitrogen and chemical oxygen demand stipulated in national standards, it is necessary to add a certain amount of various chemical reagents to the sample for reaction, and then perform quantitative determination by volumetric or spectrophotometric methods. [0003] Such as figure 1 As shown, a water quality online monitoring system produced by Systea Company in Italy, the water sample to be tested, various reagents, standard liquid, and zero liquid are respectively connected to the peristaltic pump through the valve, and the peristaltic pump is connected to the reaction chamber, the measurement chamber, and the measurement chamber in turn. One end is connected to the outside world. The light emitted by the light source passes through the mixed liquid in the ...

AI Technical Summary

Problems solved by technology

Each reagent requires a solenoid valve to control, so that when there are many kinds of reaction reagents, the connection and switching control of the flow path are very complicated, and it is difficult to realize multiple monitoring indicators on the same instrument, resulting in insufficient expansion functions

[0006] 2. The structure is complex, using multiple solenoid valves connected to each reagent, and the reaction and measurement between the tested water sample and the reagent are placed in two devices.

[0007] 3. Due to the existence of dead volume inside the solenoid valve and connecting devices, various reagents are easy to remain in the flow path, resulting in mutual interference between the two measurements; and it is very easy to cause crossover between different reagents when the flow path is switched. Contamination, which reduces measurement accuracy

[0009] 5. Long response time. For example, when monitoring COD in water, the reaction chamber is connected to the outside world, and the pressure in the reaction chamber is the same as that of the outside world. Under this condition, various reagents need to be in the reaction chamber for a long time to fully react.

Adequate mixing between water sample and reagent also takes a long time

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