Do you all know what initial rainwater collection tanks are used for? Does anyone know what the difference between it and the accident pool is?

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The 25th National \"Safety Production Month\" in 2026: Everyone should talk about safety and know how to handle emergencies; identify and address potential risks and hazards. -------------------------------------------------- I first heard of initial rainwater collection tanks in 2016, during the construction of a chemical plant project. I had no idea what they were for at that time; I just thought that rainwater needed to be collected somehow, after all, it’s sufficient to separate rainwater from wastewater. It wasn’t until chemical production started that, after a rainstorm, the rainwater discharged from the main outlet exceeded the allowed limits. We then tried to find out the reason for this issue; our workshop collected some rainwater for testing, and its levels were indeed above the limit. It was then that I first realized the importance of initial rainwater collection tanks. At the beginning of rainfall, the water dissolves a large amount of acidic gases and other polluting gases present in the air, such as those emitted by factories. As the rain falls on rooftops, chemical production facilities, asphalt concrete roads, etc., it washes away various pollutants from chemical plants, including waste residues, waste materials, waste liquids, suspended particles, and solid particulate impurities. If this initial rainwater is discharged directly into the rainwater system without treatment, the levels of pollutants in the wastewater discharged from the main outlet will inevitably exceed the limits. This is where the function of the initial rainwater collection tank becomes apparent: it collects the initial rainwater first, and once the surface has been cleaned to a sufficient extent, the subsequent rainwater can be directed directly into the rainwater drainage system. The rainwater collected in the initial rainwater collection tanks after the rain stops is discharged after passing through pretreatment processes or being processed at the sewage treatment plant to meet the required standards. What is the concept of an accident pool? According to the national standard GB/T50483-2019, it refers to an emergency storage structure specifically designed to contain leaked hazardous chemicals, fire-fighting wastewater, and polluted rainwater during accidents. It must remain empty under normal conditions and must not be filled to capacity; its function is to prevent accident-related wastewater from leaking outside the facility and thus avoid secondary water pollution. It constitutes a mandatory environmental protection and safety emergency facility. Three types of wastewater are collected: 1. Liquid hazardous chemicals leaking due to damage to storage tanks/apparatuses ； 2. Fire fighting generates toxic/oily fire-fighting wastewater ； 3. Polluted rainwater converging in the plant area during the accident period. In terms of function, the two are not the same thing; an initial rainwater collection tank is an environmental protection facility. An accident pond is an environmental protection + emergency facility. Under normal operating conditions, the initial rainwater collection tank collects polluted rainwater that has washed the factory floor over a period of 15–30 minutes for every 20–30 mm of rainfall. Function: Separation of dirty and clean water; during the initial phase, dirty rainwater is sent to the sewage treatment plant, while clean rainwater is discharged directly ； Control daily non-point source pollution, and ensure regular water inflow on rainy days. The accident emergency pool is activated in the event of emergencies such as fires or leaks, and it is used to hold hazardous chemical leaks, fire-fighting wastewater, and stormwater generated during such incidents. Function: Prevent accident-related waste liquids from leaving the facility and avoid severe water pollution; it must remain empty under normal operating conditions. The focus of routine operation control inspections also varies. The initial rainwater collection tank can store water; after rainfall, the water should be pumped to the sewage treatment station as soon as possible to empty it, allowing for continuous cyclic use with frequent refilling. The accident tank should be completely empty at all times; it is strictly prohibited to store water in it ； The temporary occupation shall be ≤1/3 of the tank, and it must be possible to empty it urgently within 30 minutes (Petrochemical Q/SH0729).