1. Chroma: if the chroma of drinking water is greater than 15 degrees, most people can detect it. If it is greater than 30 degrees, people feel disgusted. The standard specifies that the color of drinking water shall not exceed 15 degrees.
2. Turbidity: it is an expression of the optical properties of water samples, used to express the degree of water clarity and turbidity. It is one of the most important indicators to measure the good degree of water quality, and also an important basis for assessing the purification efficiency of water treatment equipment and evaluating the state of water treatment technology. The decrease of turbidity means the decrease of organic matter, bacteria, virus and other microorganisms in the water, which can not only improve the disinfection and sterilization effect, but also reduce the generation of halogenated organic matter.
3. Odor and odor: the production of water odor is mainly due to the presence of organic matters, which may be caused by the increase of biological activity or industrial pollution. The change of normal odor in public water supply may be a signal of the change of raw water quality or inadequate water treatment.
4. Visible to the naked eye: mainly refers to particles or other suspended substances in water that can be observed by the naked eye.
5. Residual chlorine: residual chlorine refers to the amount of chlorine left in the water after a certain period of contact after chlorination. The continuous bactericidal ability in the water can prevent the self pollution of the water supply pipeline and ensure the water quality.
6. Chemical oxygen demand: refers to the oxygen demand for the oxidation of organic pollutants in water by chemical oxidants. The higher the chemical oxygen consumption, the more organic pollutants in the water. The organic pollutants in the water mainly come from the discharge of domestic sewage or industrial wastewater, the decomposition of animals and plants, and then flow into the water body.
7. Total number of bacteria: the bacteria in the water are from the air, soil, sewage, garbage, animal and plant bodies. There are many kinds of bacteria in the water, including pathogenic bacteria. The standard of drinking water in China is that the total number of bacteria in 1ml water is less than 100.
8. Total coliform bacteria: it is an indicator bacteria of fecal pollution. The detected situation can indicate whether there is fecal pollution in the water and the degree of pollution. In the process of water purification, after disinfection treatment, if the total coliform index can meet the requirements of drinking water standards, it shows that other pathogens are basically killed. The standard is no more than 3 / L in the test.
9. Thermotolerant coliform group: it more closely reflects the degree of food pollution by human and animal feces than coliform group, and it is also an indicator of water feces pollution