Briefly describe the main sources of chemical pollutants.

Discharge of wastewater and waste gas, breathing from atmospheric pressure storage tanks, minor leaks from gaskets and packing, sampling, maintenance of pumps and machinery, discharge in emergency situations, laboratory analysis processes, disposal of reagents, leaks and spills.

Running, dripping, leaking, discharge, and those caused by accident reasons

The main sources of chemical pollutants can be roughly divided into the following two categories. 1. Raw materials for chemical production. Semi-finished products and finished products: 1. Incomplete chemical reactions. In current chemical production processes, it is not possible to convert all of the raw materials into semi-finished products or finished products; there is an issue related to the conversion rate. Although some of the unreacted raw materials can be recycled, eventually a portion of them is discharged due to incomplete recycling or because they cannot be recycled. If the chemical raw materials are harmful substances, their discharge will cause environmental pollution. 2. Impure raw materials: Sometimes the raw materials themselves do not have sufficient purity and contain impurities. Since these impurities are not required to participate in the reaction, they must be discarded. Therefore, when such impurities are harmful substances, they can also cause pollution to the environment. 3. Running, leaking, dripping, seeping – due to inadequate sealing of production equipment and pipes ； Or due to poor operation and management ； Materials science often leads to leaks during storage, transportation, and production processes. *It is commonly referred to as the phenomena of running, leaking, dripping, and seeping. The occurrence of this phenomenon not only causes economic losses but also leads to severe pollution incidents, resulting in unpredictable consequences. II. Waste generated during chemical production processes 1. Fuel combustion: Chemical production processes must take place under certain pressures and temperatures; therefore, energy input is required, which entails burning large amounts of fuel. During fuel combustion, a large amount of flue gas is inevitably emitted. In addition to dust, smoke also contains other harmful substances that pose a serious threat to the environment. 2. Cooling water: In the chemical production process, in addition to a large amount of heat energy, a significant quantity of water is also required for cooling purposes. For example, producing one ton of caustic soda requires about 100 tons of water. During the production process, water is used for cooling, and there are generally two methods: direct cooling and indirect cooling. When direct cooling is used, the cooling water comes into direct contact with the material being cooled, which easily allows chemical substances in the water to become pollutants. When indirect cooling is used, although the cooling water does not come into direct contact with the material, chemicals such as preservatives and algaecides often need to be added to it, and their discharge can also cause pollution problems. Therefore, the cooling water used in chemical production processes should be reused as much as possible to reduce emissions, which not only helps conserve water resources but also prevents pollution, yielding both economic and environmental benefits. 3. Side reactions: In chemical production, alongside the main reaction, there are often some unwanted side reactions that occur. Although some side reaction products (by-products) can be turned into useful substances after being recovered, the small quantity of these by-products and their complex composition often make recovery a challenging task that requires significant financial investment. As a result, they are usually discarded as waste, leading to environmental pollution. In addition to waste emissions resulting from side reactions, chemical production processes sometimes require the addition of substances that do not participate in the reactions, such as various solvents and additives; these substances also cause environmental pollution when they are discharged as waste. In short, the waste discharged by the chemical industry takes the form of three types of substances: wastewater, waste gas, and solid waste, collectively known as the \"three wastes\" of the chemical industry. Because any waste is not absolutely a “waste” in itself. Once people make rational use of waste, it is entirely possible to \"turn waste into treasure.\"

They are nothing but wastewater, waste residues, and waste gases; their sources are quite diverse, as explained upstairs. Leaks are one cause; normal organized emissions and unorganized emissions are also causes. Another reason is improper recycling.

In general, it refers to the emission of wastewater and waste gases! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !