The chemical industry is one of the basic industries of my country's national economy. At the same time, it is an industrial sector that has a large amount of "three wastes" and is prone to pollution and harms the environment. It is called a "big polluter".

(1) About 70% of the environmental pollution caused by sewage from the chemical industry comes from industrial pollution. Generally speaking, what kind of industrial production will produce what kind of pollution sources and pollutants. The characteristics of chemical production determine the universality and complexity of chemical pollution.

1. There are many industries and varieties. The chemical industry includes fertilizers, pesticides, dyes, coatings, chlor-alkali, soda ash, sulfuric acid, nitric acid, inorganic salts, carbon black, reagents, rubber processing, petrochemicals, organic chemicals, rubber additives, chemical mines, etc. There are more than a dozen industries, and some industries include many small industries, producing more than 40,000 kinds of chemical products. Since the raw materials and production methods used for each product are different, the pollution sources and pollutants produced are also different, which can be said to be complex and diverse, and the quantity is large and wide.

2. There are many small and medium-sized chemical enterprises. Among the six state-owned enterprises in the country, 80% of the old enterprises are small and medium-sized enterprises. If you add tens of thousands of township chemical enterprises, small and medium-sized enterprises are even harder to count. It is precisely because these small and medium-sized enterprises and old enterprises have a poor foundation, relatively outdated technology, and heavy pollution.

3. The environment and process of chemical production are complex. Most chemical production is carried out under the conditions of high temperature, high pressure, flammable, explosive, strong acid, and strong alkali. Not only does it have many side reactions, it is also extremely easy to corrode equipment and pipelines, causing materials to run away, Emitting, dripping, and leaking; long process flow and improper operation of workers will reduce the conversion rate of raw materials and product recovery rate, causing environmental pollution; and the selection of raw material routes and production methods are different, and the types and quantities of "three wastes" are also large. Not the same.

4. Chemical production involves a wide range of materials, with different components. The raw materials, additives, solvents, catalysts and products used in chemical production are generally toxic, irritating, volatile and corrosive. Some raw materials are non-toxic or have little toxicity. However, it will decompose or generate toxic substances through chemical reactions.

5. Chemical pollution is closely related to management level. According to incomplete statistics, chemical pollution is about 30%. 40% is caused by poor management. Mainly due to the long process flow and multiple procedures, which link is not strictly managed, equipment and pipeline maintenance is not good, not carefully operated, and the material ratio is not properly controlled, which will increase side reactions and cause material loss and aggravate pollution.

6. The treatment of chemical pollution is difficult, and the technical requirements are high. Most of the pollutants produced by chemical production are the same as other industrial production, but there are many unique pollutants, such as organic phosphorus sewage, organic chloride sewage in pesticide production, and dye production. In the current conditions, the waste water of fluorine series, benzene series, high-concentration non-ferrous sewage, distillation residues in organic chemical production, etc., are difficult to overcome under current conditions.

(2) Sources and characteristics of chemical waste water Generally speaking, chemical waste water comes from the chemical production process, but the reasons for its generation are various. In summary, there are mainly the following ways: (1) The mining and transportation of chemical raw materials In the process, due to the discharge of mine sewage or the loss of pollutants, sewage pollution is formed under the rain wash.