TANK CLEANING · STANDARDS EXPLAINED
Cleaning an oil storage tank is not only a matter of job safety. It also involves environmental issues such as VOCs emissions, the management of oil-bearing waste and the subsequent transfer and disposal of that waste.
During tank emptying, residual oil suction, cleaning of the tank shell and collection of oil sludge, inadequate control measures can create compliance risks such as fugitive oil vapour and non-compliant management of cleaning waste.
A properly executed tank cleaning job therefore has to consider more than "how to clean safely". It must also address how the oil vapour generated during cleaning is controlled, how the material removed from the tank is handled, and where that material finally goes.
01 VOCs during tank cleaning cannot simply be released
Crude oil, refined products and other materials remaining inside a tank may contain volatile organic compounds. If tank emptying, opening, residual oil suction and cleaning are carried out with the tank open for long periods, or without effective waste gas control measures, fugitive VOCs emissions may increase.
GB 37822—2019, Standard for fugitive emission of volatile organic compounds, sets out control requirements for the storage and transfer of VOCs-containing materials, for process operations and for open liquid surfaces.
For equipment and associated piping containing VOCs materials, the standard explicitly requires that during maintenance and cleaning:
materials should as far as possible be fully drained during the emptying stage and contained in closed vessels, and the waste gas generated during emptying, cleaning and purging should be collected and treated as required.
Tank cleaning therefore cannot focus only on whether the inside of the tank is "clean enough". Reducing open-tank operations and controlling fugitive oil vapour are equally important elements when a company draws up a cleaning plan.
It should also be noted that sector-specific pollutant emission standards and local environmental requirements may apply. Individual projects should always be executed in line with the company's industry sector, the stored medium and the requirements of the local regulator.
02 The oil sludge and waste liquid removed are not ordinary waste
Once cleaning is complete, how the residual oil, oil sludge and oil-water mixtures are handled is another key part of environmental management.
The National Catalogue of Hazardous Waste (2025 edition) states that, in the refined petroleum products manufacturing sector, the oil/water and hydrocarbon/water mixtures generated when cleaning mineral oil storage and transfer facilities fall under HW08, "waste mineral oil and mineral oil-bearing waste", with waste code 251-001-08.
This does not mean that the oil sludge and waste liquid from every tank cleaning job at every company can be assigned that code directly.
Whether material generated by tank cleaning constitutes hazardous waste, and which waste category applies, must be assessed on the basis of the generating company's industry sector, the process stage involved and the actual properties of the waste.
This is why the onward routing of residual oil, waste water and oil sludge should be built into the overall plan before a tank cleaning project starts, rather than looking for a disposal route once cleaning has finished.
03 Once classified as hazardous waste, "taken away" does not mean managed
Where material generated by tank cleaning is classified as hazardous waste, its subsequent storage, transfer, recovery and disposal must continue to follow hazardous waste management requirements.
GB 18597—2023, Standard for pollution control on hazardous waste storage, sets mandatory provisions covering containers and packaging, storage facilities, the storage process and environmental management for hazardous waste.
For transfer, the Measures for the Administration of Hazardous Waste Transfer require the hazardous waste transfer manifest system to be applied, with electronic manifests completed and operated through the national hazardous waste information management system.
Reference case
In March this year, the Shanghai Municipal Bureau of Ecology and Environment published a case directly related to tank cleaning: it approved the "point-to-point" targeted utilisation of waste base oil generated during tank cleaning by the companies concerned, in line with filing requirements.
The case shows that identification of tank cleaning residues, together with their transfer, utilisation and record keeping, is itself part of the environmental management chain of a tank cleaning project.
04 The choice of cleaning method increasingly has to balance environmental performance
From safety to environmental protection, tank cleaning is gradually moving from the single goal of "getting it clean" towards whole-process management of the working method, oil vapour control, residual oil recovery, waste collection and downstream disposal.
The value of mechanised cleaning is not limited to keeping people out of the tank.
A more standardised mechanised working method reduces unnecessary open-tank operations and allows residual oil, cleaning media and generated waste to be collected and managed centrally, helping companies balance safety, environmental performance and project execution efficiency when planning a tank cleaning job.
Tecway Industrial | Tank cleaning equipment rental and cleaning services
For companies with periodic tank inspection and cleaning requirements, Tecway Industrial offers rental of mechanised tank cleaning equipment together with supporting cleaning services, with cleaning packages configured flexibly according to tank type, project duration and site requirements.
For companies that do not need to own a full cleaning spread long term, the rental model reduces one-off equipment investment. At the same time, mechanised cleaning reduces the need for personnel to enter tanks for high-risk work, improving efficiency while better addressing safety management and project execution needs.
References
- Ministry of Ecology and Environment: GB 37822—2019, Standard for fugitive emission of volatile organic compounds
- Ministry of Ecology and Environment and others: National Catalogue of Hazardous Waste (2025 edition)
- Ministry of Ecology and Environment: GB 18597—2023, Standard for pollution control on hazardous waste storage
- Ministry of Ecology and Environment, Ministry of Public Security, Ministry of Transport: Measures for the Administration of Hazardous Waste Transfer
- Shanghai Municipal Bureau of Ecology and Environment: Reply approving the filing for "point-to-point" exempt utilisation of waste tank cleaning oil transferred from Sinopec Lubricant Co., Ltd. East China Branch to Sinopec Shanghai Gaoqiao Petrochemical Co., Ltd. (Gaoqiao base)
About Tecway Industrial
Tecway Industrial Systems Limited, formerly Tecway International (Petrochemical) Limited, was established in Hong Kong in 1995. Beijing Tecway Xuyang Industrial Equipment Co., Ltd. is its Beijing-registered subsidiary.