COD online monitor is a kind of water quality online monitoring equipment, also known as chemical oxygen demand online monitor, refers to the amount of oxidant consumed by reducing substances in the water body that are easily oxidized by strong oxidant, and the result is converted into the amount of oxygen , Expressed in mg/L. COD measurement methods can be divided into potassium dichromate method and potassium permanganate method according to the different types of oxidants. The COD value indicates the degree of organic pollution in water. For example, measurement and analysis of highly polluted water samples such as domestic sewage and industrial wastewater are detected by the potassium dichromate method; for example, the measurement of permanganic acid for surface water such as seawater and lake water Potassium method detection. However, when the COD monitor measures the water sample, the chloride ion content in the water sample should not exceed 2000 mg/L, and the high chloride ion content will lead to inaccurate measurement values ??of the instrument.
The measurement range of the COD online monitor is 0-6000mg/L, the accuracy does not exceed ±10%, and the repeatability does not exceed ±10%; the power supply voltage of the COD online monitor is AC220V±15%, and the power frequency is 50Hz±5%, The power of the power supply is more than 2000w. For areas with unstable voltage and frequent power outages, it is recommended to use an AC power regulator with matching power to protect the instrument.
The selection of the pump when the COD online monitor is installed. The power of the pump that delivers water samples from the sampling point to the instrument should be such that the flow rate of the measured water body to the instrument is not less than 50 liters/minute, not more than 200 liters/minute. .
When the distance between the sampling point and the instrument is usually less than 20 meters during installation, choose a 350W submersible pump. When the distance between the sampling point and the instrument is greater than 20 meters, the submersible pump of 550-750W should be selected, and the corrosion-resistant pump should also be considered based on the corrosivity of the water sample. Air, temperature, and water are all factors that affect the measuring agent of the COD online monitor.
What are the advantages of COD online monitor? 1. Large measuring range; 2. Low reagent price and low consumption; high reliability and anti-interference of the instrument; few components and easy maintenance.
What are the installation requirements for the sampling and sampling system of the monitoring equipment?
(1) The sampling and water intake system should ensure that representative water samples are collected, and that the water samples are transferred to the monitoring station building without any change of texture to be sampled and analyzed by the automatic water supply quality analyzer or sampler.
(2) The sampling water intake system should be located as far as possible in the center of the flow path at the head of the waste water discharge weir, the front end of the water collection is set in the downstream direction, and the front end of the water collection section is less blocked. When measuring the drainage of a river, collect water in a well-mixed place behind the river. The sampling water intake system should be set to move up and down with the fluctuation of the water surface. A manual sampling port should be set at the same time for comparative testing.
(3) The structure of the sampling water intake system shall have necessary anti-freezing and anti-corrosion facilities.
(4) Sampling water intake pipe materials should be free of interference from the monitored items and resistant to corrosion. The water intake pipe should be able to ensure the flow required by the automatic water quality analyzer. Sampling pipelines should be made of high-quality rigid PVC or PPR pipes. It is strictly forbidden to use hoses as sampling pipes.
(5) The sampling pump should be reasonably selected according to the sampling flow rate, the head loss of the sampling water intake system and the water level difference. The water sampling pump should have no effect on water quality parameters, and has a long service life and easy maintenance. The installation of the sampling water intake system should facilitate the placement and maintenance of the sampling pump.
(6) The sampling water intake system should be equipped with filtering facilities to prevent the coarse particles suspended in the debris box from damaging the sampling pump.
What are the main contents of daily inspections of water quality monitoring stations?
1. Check the sampling system;
2. Self-inspection of standard samples of analysis monitor;
3. Check the working condition of the analysis monitor;
4. Check the data collection system;
5. Check the status of other instruments and equipment in the monitoring station;
6. Check the external conditions of the substation;
7. Cleaning work inside and outside the monitoring station;
8. Check the actual reagent status and inventory.
Application case: Coca-Cola site, water quality environmental protection monitoring acceptance acceptance is complete