Discussion on the prevention measures and Counterm

2022-08-02
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As we all know, the successful disposal of each chemical disaster accident is inseparable from water, such as dilution, degradation, explosion-proof, cooling, preparation of foam premix, etc. a large amount of water must be provided for each link. The longer the operation time, the greater the water consumption. But the fire water itself is clean and pollution-free. What can cause pollution is mainly the mixture of accident water and toxic materials. Instead of entering the sewage pipeline or buffer pool, it enters the rain drainage pipeline and directly flows into the river, river, lake, sea, farmland and grassland. The degree of harm depends on the leakage of hazardous chemicals under accident conditions and the collection, storage, transportation and treatment capacity of wastewater. On january8,2006, the State Council issued the national overall emergency response plan for public emergencies, which clearly proposed to establish a social early warning system to deal with accidents and disasters, and took the prevention of pollution and other secondary disasters as an important content. Therefore, the public security fire forces should not only focus on preventing and controlling disasters and ensuring the safety of people's lives and property, but also on preventing environmental pollution

on November 13, 2005, the nitration unit of the aniline unit in the double benzene plant of PetroChina Jilin Petrochemical Company, the largest aniline production base in China, exploded and caused a fire, resulting in 8 deaths and 60 injuries. The fire water used in explosion control and fire fighting already contains a large amount of benzene toxic substances. These wastewater flows into the Songhua River, creating an 80km long pollution zone, forcing the supply of drinking water in the urban area of Harbin to be cut off for four days. More than 3 million Harbin citizens have encountered an unprecedented drinking water crisis. The Songhua River water pollution incident is by far the most serious one in China, which was caused by the inland water system pollution and then spread to the international boundary river Heilongjiang. The lesson is undoubtedly profound. At the same time, it also sets up the concept of environmental protection for the modern public security fire forces, and puts forward a new topic on how to prevent the occurrence of secondary disasters in the rescue operation of handling chemical accidents, that is, how to prevent the occurrence of secondary pollution accidents; How to minimize the impact and loss caused by pollution accidents; How to improve the ability of fire commanders and fighters to prevent accidents and environmental pollution under accident conditions. In this regard, on the basis of summing up years of experience in fire fighting and rescue work, the author consulted a large number of relevant materials and listened to the guidance of authorities, and then made some superficial understanding

I. concept and classification of wastewater pollution in chemical accident disposal (I) concept

after the occurrence of most chemical accidents, various secondary disasters will be associated or derived, and it often forms a disaster chain, which continuously causes serious harm to people's normal life and ecological environment. Sometimes, the consequences of secondary disasters will exceed those of primary disasters. In the rescue operations for chemical accidents, water is the most commonly used agent for fire extinguishing, cooling, dilution and decontamination. However, the pollution of the accident site and the environment caused by the used wastewater and the secondary disasters caused thereby are inevitable. However, to what extent can waste water cause pollution to the ecological environment, which is called the secondary disaster of chemical disaster accidents, and should be paid attention to and used as the basis for the evaluation of secondary disasters? The water pollution prevention and control law of the people's Republic of China promulgated in 1984 clearly defines "water pollution":

that is, the chemical, physical, biological or radioactive characteristics of a water body are changed due to the intervention of a certain substance, which affects the effective use of water, endangers human health or destroys the ecological environment, resulting in the deterioration of water quality, which is called water pollution

(II) classification

in chemical accidents, the pollutants are mainly chemicals. Therefore, the water pollution is mainly chemical pollution, which can be divided into six categories:

1 Inorganic pollutants

the inorganic pollutants that pollute the water body include acid, alkali and some inorganic salts. This kind of pollution can change the pH value of the water body and hinder the self purification ability of the water body

2. Inorganic toxic substances

inorganic toxic substances that pollute water bodies are mainly heavy metals, non-metals and other substances with long-term potential effects. There are mainly mercury, cadmium, lead, arsenic, sulfur and other elements

3. Organic toxic substances

the organic toxic substances that pollute the water body are mainly various organic pesticides, polycyclic aromatic hydrocarbons, halogenated hydrocarbons, etc. Most of them are synthetic substances with very stable chemical properties and are difficult to be degraded

4. Aerobic pollutants

carbohydrates, proteins, fats, phenols, alcohols and other organic substances contained in some industrial wastewater can be decomposed under the action of microorganisms. A large amount of oxygen is required in the decomposition process, so it is called aerobic pollutant

5 is a major obstacle to the realization of healthy and sustainable development Plant nutrients mainly include nitrogen, phosphorus and other plant nutrients in industrial sewage

6. Oil pollutants mainly refer to the pollution of oil and petroleum products to water bodies

II. Characteristics and hazards of wastewater pollution in the treatment of chemical accidents

(I) characteristics

during the treatment of chemical accidents, due to the large amount of water used for fire extinguishing, cooling, dilution, decontamination and other measures, these water are very easy to mix with the leaked chemical raw materials and chemical products to form fire-fighting wastewater, which constitutes pollution to the environment during its flow. In particular, petrochemical enterprises use oil or natural gas as the main raw material to produce various petroleum products through different processes. The materials with various components are processed, stored, loaded and unloaded here. Once an accident occurs, it is very easy to cause the containers and pipelines to break. The leaked materials are mixed with the fire water, and the fire water will be polluted. Generally, this part of polluted fire-fighting wastewater is collectively referred to as sewage. If it is not properly disposed, it is very likely to cause serious water pollution accidents

(II) hazardous disposal of a large amount of sewage left over from chemical accidents has serious harm to the natural environment and people's production and life. To sum up, its harmfulness mainly includes the following points:

1 Water pollution in chemical accidents is a secondary disaster after chemical accidents. Due to the uncertainty and contingency of the time and place of chemical accidents, a large number of toxic and harmful substances will be leaked in a short time. For example, in 1987, a fire broke out in a paint factory in Dayton, Ohio, USA. Since the plant is located on the watershed of the municipal water supply system, in order to avoid the sewage with paint and other chemicals flowing into the urban water source, only a small amount of water was used to extinguish the fire. Later, the fire pump that was supplying water had to be turned off to stop the fire. VTT was studying the foaming method of bioplastics and watched the paint plant burn out

2. A wide range of hazards

after the occurrence of water pollution in chemical accidents, toxic substances seriously pollute surface water sources and even pollute rivers, expanding the scope of harm and damaging the ecological environment. For example, on november1,1986, a fire broke out in a chemical warehouse with a large amount of oil from the santorque oil return pipeline in Basel, Switzerland. Firefighters used millions of gallons of water to fight the fire. As a result, the fire-fighting water mixed with about 30 tons of pesticides and other chemical raw materials flowed into the famous Rhine River in Western Europe, resulting in the death of a large number of fish and other aquatic animals and plants, seriously damaging the ecological environment there. France, Germany, the Netherlands and other five countries that the river flows through are also deeply affected. This accident is the most serious environmental pollution disaster in history

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