Several industries such as chemical, food processing, mines & minerals, petro-chemical, power generation, waste water treatment and many others face the problem of tank bottom sludge. But before proceeding any further, let us understand what sludge is all about and what majorly constitutes in its formation.


Crude oil which is found beneath the earth’s surface is untreated in its purest form. The problem of contamination begins when the contaminants present in crude settles down at the bottom of the storage tanks. Sludge therefore, is formed due to sand, rust and scale from piping and tank walls sink to storage tank bottoms. The main constituents of sludge are hydrocarbons, sediment, paraffin and water.

This combination has the tendency to accelerate the corrosion activity within the tanks. As a consequence, it greatly reduces burner ignition time and storage capacity due to a clogged nozzle and filter. The problem of sludge can be aggravated if water is present in the tank because it causes microorganisms to grow and thereby oxidizing the oil.

More than 90 percent of sludge consists of hydrocarbons. Therefore, it is imperative that the personnel cleaning the tanks should spend minimum time cleaning inside the tank. They are exposed to several hazards which can be a cause of injury or even death in certain circumstances. The sludge tank is hazardous due to -

Chemicals -
The cleaning crew while cleanup might get exposed to hazardous chemicals such as polycyclic aromatic hydrocarbons and benzene. There are certain chemicals that show an instant reaction whereas other takes time to reveal impact. Exposure is possible if one inhales, touches or accidentally ingests such poisonous chemicals. It is advisable to wear appropriate protective gear while cleaning.

Flammable Material -
Before starting the tank cleaning process, ensure about the material that is capable of bursting into fire is removed from the surroundings. To ensure the safety of the personnel, ask them to leave the tank until it is absolutely safe. This will be followed by monitoring the tank atmosphere until all the sludge has been removed.

Microbes -
Microbes grow in spaces where sludge consists of water as well apart from hydrocarbons. The water acts as a breeding ground for the microbes and exposure to such microbes might result in an allergic reaction or infection.


Sludge formation is preventable if due care and attention is given to the fuel tank by making use of the professional thermal remediation services. They will employ several techniques such as furnace tune-ups and filter changes at regular intervals and prevent water from entering the tank. Once formed, the sludge can be treated by using the following methods -

• Thermochemical Processes -
This process involves heating the sludge at extremely high temperatures which melts it and finally disperses it. It is regarded as oft used, affordable, safe and efficient method.

• Centrifuge -
For minimizing wastage, the sludge is treated for maximum oil extraction. The final extraction process depends on sludge viscosity.

• Hydrocarbons -
Sometimes, taking out the sludge from the tank could be a daunting task. So, workers in such a situation dissolve the sludge using hydrocarbons. This will be followed by releasing high-pressure crude oil into the tank and facilitating the sludge to pump more easily out of the tank.

Therefore, oil being the non-renewable resource is very precious to the mankind and its regular maintenance using high quality environmental remediation equipment assumes a lot of significance. This will prevent failures of the heating systems, reduce soot, improve combustion and significantly help in energy conservation by reducing oil wastage.



About Author / Additional Info:
I am a freelance writer and blogger who is inclined towards environment protection niche mainly. I try to highlight the various threats to environment and our surrounding and the latest trends and industrial tools and techniques to help fight with these environmental threats.