What are the hazards of excessive COD to the human body?

COD is Chemical Oxygen Demand.

The code indicates the amount of oxygen required for potassium dichromate to oxidize one liter of organic matter in sewage under strong acidic conditions, which can roughly indicate the amount of organic matter in sewage.

It is an indicator of the amount of reducing substances in the water. The reducing substances in the water include various organic substances (mainly organic matter) and nitrite.

Sulfides, ferrous salts, etc. For this reason, chemical oxygen demand (COD) is often used as a measure of the amount of organic matter in water. The higher the COD, the more polluted the water body is by organic matter.

Toxic organic matter enters the water body), which not only harms the organisms in the water body such as fish, but also can accumulate through the food chain and finally enter the human body, causing chronic poisoning. Chronic poisoning, for example, DDT can affect the nervous system, disrupt liver function, cause physiological disorders, and may even affect reproduction and genetics, produce freaks and cause cancer. Wait.

The reasons for COD exceeding the standard include changes in the oxygen supply environment and self-factors.

1. Changes in the oxygen supply environment.

The sludge produced in the secondary sedimentation tank is mainly in the biofilm after shedding, because the biofilm is mainly aerobic bacteria, in the oxygen supply environment from aerobic to anaerobic, a large number of aerobic bacteria rupture, cytoplasm dissolution, part of the facultative bacteria and anaerobic bacteria use synthetic bacteria, part of the water body into the degradation of COD. Due to the presence of a large amount of sludge, the COD in the secondary sedimentation tank does not decrease but rises.

2. Self-factors.

The COD generated in the production of enterprises will be too high, such as residues in food factories, pickling wastewater in the electroplating industry, and reducing substances in chemical plants.

Chemical oxygen demand, or COD, represents the amount of oxygen required for potassium dichromate to oxidize one liter of organic matter in sewage under strong acidic potato conditions, which can roughly represent the amount of organic hand fuel in sewage. Generally, the oxidants used to measure chemical oxygen demand are potassium permanganate or potassium dichromate, and the values obtained by different oxidants are also different, so the detection method needs to be indicated. In order to be uniform and comparable, all countries have certain monitoring standards.

You should be talking about excessive COD in the wastewater of the distillation process in methanol production, right?

This has a lot to do with your process, if the distillation column you use does not have environmental protection measures, that is, the wastewater stripping tower, then the main reason is that the methanol content in your reactor liquid is high, and the main reason is: the return flow control is too large, and the temperature of the reactor is low. Sometimes the liquid level of the tower kettle fluctuates greatly, which is also easy to cause the discharge of sewage to be unqualified.

If you have an environmentally friendly stripper, then the main reason should be in the stripper, and there are three reasons for analysis: 1. The reflux control of the stripper is too large, resulting in a high alcohol content at the bottom of the tower; 2. The material entering the stripper fluctuates greatly, resulting in the unstable material balance of the stripper; 3. The temperature control of the stripper is low, and the temperature of the stripper should be greater than 97 at least at normal pressure. If none of these are the three, you need to consider whether there is a problem with the tray or packing used in the stripper.

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COD is an indicator that describes the amount of organic matter in water. There is no direct harm to the human body.

1. Reasons for excessive COD in sewage - (due to its own production).

The generation of COD in the production process of enterprises can be said to be inevitable, such as the residue of excess food and water in food factories, the reducing substances S ions and chloride ions in chemical plants, and electroplating wastewater in the pickling process are the reasons for excessive COD in sewage.

2. The reason for the excess COD of sewage - (water treatment process defects).

1) Biochemical treatment (water temperature is too low): When the temperature is too low, the activity of the strain is also low, thereby reducing the decomposition of COD.

2) Insufficient dissolved oxygen in water: When the dissolved oxygen in the water is insufficient to meet the metabolism of the bacteria themselves, it will cause the lack of bacteria. The efficiency of sewage COD treatment is greatly reduced.

3) The concentration of a certain index (ammonia nitrogen, heavy metals) in wastewater is too high: too high an index in sewage will poison the bacteria in the biochemical tank and make COD unable to degrade.