A Novel Process for the Challenges of Refining Wastewater Treatment
Main characteristics of refining wastewater:
Rich in organic matter: such wastewater contains high concentrations of organic components, mainly hydrocarbons and their derivatives. These substances are difficult to biodegrade naturally, keeping chemical oxygen demand (COD) high.
Diverse composition: the wastewater contains a wide variety of organic compounds, inorganic substances and heavy metals. These require special consideration in treatment to avoid potential risks to ecosystems and living organisms.
High oxygen demand indicators: biochemical oxygen demand (BOD) and chemical oxygen demand (COD) are key parameters for assessing wastewater pollution. Both are high in refining wastewater, reflecting a heavy organic load and presenting challenges for treatment processes.
High salt content: the various solvents and additives used in the refining process raise the salt concentration of the wastewater, which inhibits the activity of microorganisms in biological treatment units.
High temperature and high pH: the high-temperature wastewater discharged from production and the chemicals used together make the wastewater typically alkaline, mostly in the range of pH 7.5 to 8.5.
Strong fluctuation: the quality and quantity of such wastewater often fluctuate significantly, requiring the treatment system to have excellent adaptability and operational stability.
Treatment challenges:
High organic load: wastewater from many chemical processes contains extremely high organic concentrations — COD can reach tens of thousands of mg/L — mostly beyond the range permissible for direct biological treatment.
Complex and varied composition: the organic substances, inorganics and heavy metals in the wastewater vary widely in combination and concentration, greatly increasing treatment difficulty.
Toxicity and inhibition: the wastewater may contain components that are toxic or inhibitory to microorganisms, such as heavy metals and organic solvents. These hinder the growth and metabolic activity of microorganisms in biological treatment systems, impairing treatment performance.
Colour and turbidity: chemical wastewater often has deep colour and high turbidity, which are usually difficult to remove effectively by conventional biological treatment and call for specialised processes.
In response to the difficult characteristics of refining wastewater, SINOKLE Technology, drawing on its independently developed CDOFCDOF technology, has innovatively proposed a completely new process scheme aimed at efficiently degrading organic matter in wastewater and significantly improving its biodegradability.
CDOFProcess flow diagram
CDOF- Cyclonic Dissolved Ozone Flotation unit, The unit is the company's patented technology. It integrates multi-stage catalytic ozone oxidation, hydrodynamic cavitation and cyclonic dissolved gas flotation. It is the first of its kind in China and reaches internationally advanced levels as an integrated high-efficiency oxidation and flotation device, rapidly and effectively removing petroleum substances, suspended solids, colloids, chemical oxygen demand (COD), bacteria and other pollutants from wastewater. The complete system comprises an oxygen generation unit, an ozone generation unit, a high-efficiency ozone dosing unit, a multi-stage catalytic reaction unit and a cyclonic dissolved gas flotation unit.
CDOFComparison of advantages with conventional ozone oxidation technology
Laboratory testing of a refining wastewater sample
Treatment results: the data show that when the ozone dose reached 150 mg/L, the effluent COD fell to 200.8 mg/L, with a total COD removal of 649.2 mg/L, corresponding to an ozone dosing ratio of 0.23. As the ozone dose increased, the colour of the sample gradually decreased; at an ozone dose of 150 mg/L the sample was essentially decolourised. The process effectively removed COD from the sample while significantly improving the biodegradability of the wastewater.
