Problems with the discharge of initial rainwater and oily wastewater from tank areas
Thread Content
Issue of discharging initial rainwater and oily wastewater from the tank area: The design approach is such that the production wastewater from the tank area flows through the underground pipelines for oily wastewater and into the production wastewater lift tank following the normal process. The initial rainwater within the first 15 minutes also enters the production wastewater lift tank via these oily wastewater pipelines and through the overflow well; after 15 minutes, the overflow well is closed, or the lift tank becomes full, at which point the clean rainwater enters the rainwater tank that may be contaminated, also through the overflow well. Is this design reasonable? Is it a violation of regulations, or which regulations is it in compliance with? Solving Standard Data Sharing Group
In such cases, it is necessary to analyze the specific circumstances of the enterprise; the design is not fixed and must be determined based on the local natural climate conditions, the patterns of rainfall, and the amount of wastewater generated during the production process. Many practical on-site issues cannot be discussed through summary-style questions such as whether something is simple and reasonable or complies with certain standards.
Such a design may have some problems in practice. In accordance with environmental protection requirements, oily wastewater should be treated separately from clean water to prevent water pollution. Therefore, the best practice is to collect and treat oily wastewater and rainwater separately. According to the current relevant regulations in our country, such as the \"Administrative Measures for Pollution Discharge Permits of Industrial Enterprises\", there are clear requirements for the treatment of oily wastewater and rainwater. Generally speaking, a diversion approach should be adopted: oily wastewater should be collected and treated separately through dedicated pipelines, while rainwater should be discharged through rainwater pipes or after being treated by rainwater treatment facilities. Therefore, according to the design approach you described, mixing oily wastewater with rainwater for collection and treatment does not meet the regulatory requirements. You need to reconsider and take appropriate measures to divert and treat these two types of water. It is recommended that you consult professional technicians in the relevant industry to ensure that the design plan complies with local environmental protection regulations and standards. .
That’s the idea, but it seems like your statement said a lot yet also said nothing at all :(:'(:'(
I didn’t quite understand; it seems there is a section where rainwater and wastewater from production are mixed together. Environmental impact assessments and inspections place great emphasis on the separation of clean and polluted water streams, and this is also reflected in the actual outcomes. It is recommended to separate rainwater only after ensuring that sewage does not mix in with it. PS: We carried out retrofits later on, at a great cost; I personally received administrative penalties: L. Acidic wastewater may exist both at the waste acid concentration site and in the irrigation area, with sewage collection and pumping pipelines in place. Since the rainwater in the irrigation area cannot be ensured to meet the standards, it is merged into the sewage pipeline system. Rainwater drainage channels have been installed around the top floor of the factory building, connecting to the main rainwater drainage ditch. The sewage ditches surrounding the ground floor of the factory building are connected in a closed loop to the sewage collection system. (Heavy rain; within a few minutes, the drainage ditch was in good condition.) There is also a sewage collection system for the oily wastewater from the air compressor station and the air storage tanks. Independent outer rain drainage ditch – no risk during rain. The plant area is equipped with an emergency rainwater pond, which remains at a low level under normal conditions. After 15 minutes of rainfall and when the rainwater drainage is satisfactory, the bypass for external discharge can be activated.
I took a look; the guidelines specify the disposal principles, but they also state that treatment should be carried out based on the type of wastewater generated by the enterprise. There is no description of such detailed plot points, so I’m not sure. Design Code for Water Supply and Drainage Systems in Petrochemical Enterprises SH 3015-2003: 4.3.2 The various drainage systems shall not be interconnected with each other. If a small amount of domestic wastewater needs to be discharged into the production wastewater system, measures must be in place to prevent harmful gases from the production wastewater from entering the domestic facilities. I think what is mainly discussed here are the connection requirements between the domestic wastewater system and other systems. Explanation of the provisions in the Design Code for Water Supply and Drainage Systems in Petrochemical Enterprises, SH 3015-2003: 4.2.4 Production areas such as towers, furnaces, pumps, heat exchangers, etc., as well as tank farms, are areas prone to contamination by chemical substances or oils. In the process design, dikes or drainage ditches are used to separate these areas from other zones. The initial rainwater in these areas contains chemical substances or oils. It should be discharged into the production wastewater system. If the wastewater is contaminated with oils, it should first be sent to an oily wastewater treatment system for oil removal. Design Code for Water Supply and Drainage Systems in Petrochemical Industries SH/T 3015-2019: 5.2.5 Initial rainwater from polluted areas such as production units and auxiliary production areas shall be discharged into the initial rainwater system or the process wastewater system. 5.2.6 Uncontaminated rainwater within the factory should be discharged into the rainwater system, with such discharge being subject to control and utilization.
You feel it’s right – the pipeline from the tank area to the overflow well before the oily wastewater lift tank is a shared section
I have two scenarios here: 1. A small retaining wall is installed within 1.5 meters of the storage tanks in the tank area; all rainwater and oily wastewater within this retaining wall flow into the oily wastewater lift tank. The water on the ground of the tank area is collected in the oily wastewater lift tank for the first 15 minutes, while any water collected after that time goes into the clean rainwater testing tank. Tests are conducted in this testing tank; if the water meets the standards, it can be discharged or reused, whereas if it does not meet the standards, it is sent to a wastewater treatment plant. 2. No small cofferdams are installed in the tank area; the water on the ground of the tank area is collected in the oily wastewater lift tank during the first 15 minutes, while all water after that time goes into the clean rainwater testing tank. Tests are conducted in this testing tank, and if the water meets the standards it can be discharged or reused; otherwise, it is sent to the wastewater treatment plant. However, in the second scenario, there are no pneumatic control valves installed on site; only manual control valves are available, and it is not possible to maintain control for 15 minutes. As a result, during rain, the water in the tank area does not flow outside. After the rain stops, if there is no oil leakage, the water is sent directly to the clean rainwater monitoring tank. If the water meets the quality standards, it can be discharged or reused; otherwise, it is sent to the wastewater treatment plant. The main goal here is to keep the water level in the tank area at no more than 0.5 meters, as there is a concern that the gas detectors might get flooded.
So, in the tank farm where no dikes are installed, the oily wastewater and clean rainwater flow out through two separate pipes, right? The two systems are each controlled by valves, so there is no issue of shared sections.