Oil Tank Farm Oily Wastewater: A New Breakthrough with SINOKLE's Purely Physical Process
In the field of petroleum storage and transportation, the oil tank farm is a key hub linking refining production with end markets. However, in storing crude oil or refined products, tanks generate large volumes of oily wastewater. This wastewater mainly comes from tank dewatering: when the water accumulated at the bottom of a tank is periodically drained, some oil is inevitably carried into the water.
It is estimated that the oil tank farm of a medium-sized petrochemical enterprise can generate tens of thousands of cubic meters of oily wastewater each year. If such wastewater were discharged directly without effective treatment, it would not only cause serious environmental pollution but also waste a great deal of petroleum resource. Against the backdrop of increasingly stringent environmental requirements, tank farm wastewater treatment has become an environmental issue that petrochemical enterprises must take seriously.
Oily wastewater treatment in oil tank farms faces many challenges:
First, the oil concentration fluctuates widely. Wastewater from different tanks, different batches and different seasons varies significantly in oil content, ranging from a few hundred milligrams per liter to tens of thousands of milligrams per liter, which makes stable operation of the treatment process difficult.
Second, the degree of emulsification is high. Crude oil or refined products in tanks are in long-term contact with water; combined with temperature changes and agitation, this forms a stable emulsion with fine oil droplets that conventional separation methods struggle to remove effectively.
Third, the composition is complex. Besides oil, the wastewater also contains suspended solids, silt and impurities, and relying on a single treatment technology alone is often not enough to meet the standard.
Fourth, environmental requirements are strict. As discharge standards have been tightened continuously, the limit for oil has fallen below 10 mg/L, and conventional processes find it increasingly hard to comply.
In the past, oily wastewater in oil tank farms was mainly treated with a combination of chemical demulsification + flotation + filtration. This traditional approach has clear shortcomings:
Reliance on chemicals: demulsifiers, flocculants and other chemicals must be added, giving high operating costs.
Prone to secondary pollution: chemical residues may cause secondary pollution.
Unstable treatment performance: poor adaptability to water quality fluctuations, with large variations in effluent quality.
Difficult oil recovery: the quality of the waste oil after chemical treatment declines, making recovery and reuse difficult.
The SINOKLE solution
For the challenge of oily wastewater treatment in oil tank farms, SINOKLE Technology (Shenzhen) has introduced a purely physical solution built around a core of 'coalescing pressure deoiler +CDFUcyclonic dissolved-air flotation'.
Core technology 1: the coalescing pressure deoiler
This unit uses specially designed coalescing media to make the tiny oil droplets dispersed in water gradually coalesce into larger oil beads, forming an oil-water layer that is easier to separate subsequently. It is particularly effective for treating high-concentration oily wastewater.
Core technology 2:CDFUthe cyclonic dissolved-air flotation unit
CDFUIt generates ultra-fine bubbles of 5-30 microns that efficiently capture residual emulsified oil droplets for deep oil removal. The whole process is purely physical separation and requires no chemical agents at all.
Advantages of the combined process
Purely physical treatment: zero chemical addition throughout, avoiding secondary pollution.
Recoverable waste oil: the separated oil is of good quality and can be recovered and reused.
High treatment efficiency: oil removal rate above 95%, with effluent oil below 10 mg/L.
Low operating cost: no continuous purchase of chemicals, giving lower long-term operating expenses.
Strong adaptability: insensitive to water quality fluctuations and stable and reliable in operation.
Typical case: a wastewater treatment project for the oil storage tank farm of a petrochemical enterprise in Sichuan
The oily wastewater generated in this company's crude oil storage tank farm has a design treatment capacity of 50 m3/h. SINOKLE adopted a combined process of 'coalescing pressure deoiler +CDFUcyclonic dissolved-air flotation', going from contract signing to equipment shipment in only two months, demonstrating efficient project execution.
After the project was put into operation, the treatment results were remarkable: effluent quality is consistently up to standard, and waste oil recovery and refining were also achieved, creating a win-win outcome for both environmental and economic benefits.
Final thoughts
Oily wastewater treatment in oil tank farms is an important environmental issue for the petrochemical storage and transportation industry. With a purely physical technology at its core, SINOKLE provides the industry with an efficient, economical and environmentally friendly solution. On the road to green development, technological innovation will always be the primary driver.
