Discussion on the selection and main measurement items of domestic water quality analysis instruments

1. Chroma: When the color of drinking water is greater than 15 degrees, most people can detect it. When it is greater than 30 degrees, people feel disgusted. The standard specifies that the color of drinking water should not exceed 15 degrees.

2. Turbidity: It is an expression of the optical properties of water samples. It is used to indicate the clarity and turbidity of water. It is one of the most important indicators for measuring the goodness of water quality. It is also an assessment of the purification efficiency of water treatment equipment and the evaluation of water treatment. An important basis for technical status. The decrease of turbidity means that the content of microorganisms such as organic matter, bacteria and viruses in the water body is reduced, which not only improves the disinfection and sterilization effect, but also reduces the amount of halogenated organic matter.

3, smell and taste: the production of water odor is mainly the presence of organic matter, may be caused by increased biological activity or industrial pollution. The change in the normal odor of the public water supply may be a sign of a change in the quality of the raw water or an inadequate water treatment.

4. Residual chlorine: Residual chlorine refers to the amount of chlorine remaining in the water after being chlorinated and chlorinated for a certain period of time. The continuous bactericidal ability in the water can prevent the self-contamination of the water supply pipeline and ensure the water quality of the water supply.

5. Chemical oxygen demand: refers to the amount of oxygen required for chemical oxidants to oxidize organic pollutants in water. The higher the chemical oxygen demand, the more organic pollutants in the water. The organic pollutants in the water are mainly derived from the discharge of domestic sewage or industrial wastewater, and the inflow of water from the decomposition of animals and plants.

6, the total number of bacteria: bacteria contained in water, from the air, soil, sewage, garbage and animals and plants, the types of bacteria in the water are diverse, including pathogens. The standard for drinking water in China is that the total number of bacteria in 1 ml of water does not exceed 100.

7. Total coliform group: It is an indicator bacteria for fecal contamination. The condition detected from it can indicate whether there is any fecal pollution and pollution level in the water. In the purification process of water, after the disinfection treatment, the total coliform index can meet the requirements of drinking water standards, indicating that other pathogens are basically killed. The standard is no more than 3 / L in the test.

8. Heat-resistant coliform bacteria: It is more apt to reflect the degree of contamination of food by human and animal feces than coliform bacteria, and is also an indicator of water body fecal contamination. 9. Escherichia coli: E. coli is a representative strain of the genus Escherichia. Generally, it does not cause disease. It is a resident bacteria in the intestines of humans and animals. Under certain conditions, it can cause intestinal infection. Some serotype strains are highly pathogenic and cause diarrhea, collectively referred to as pathogenic E. coli. Enterobacter is a group of G-bacilli with similar biological traits, which are mostly found in the intestines of humans and animals. Escherichia is one of a variety of bacteria, and Escherichia coli is the most common clinically. E. coli, commonly known as Escherichia coli, is a normal parasite in the large intestine of all mammals. On the one hand, it can synthesize vitamin B and K for absorption and utilization by the body. On the other hand, it can inhibit excessive proliferation of spoilage bacteria and pathogenic bacteria and fungi. However, when they leave the parasite of the intestine and enter other parts of the body, they can cause infection. Some bacterial types are pathogenic and cause intestinal or urinary tract infections. In short, Escherichia coli = E. coli.