The composition of oily wastewater is relatively complex, and the oil content and form of oil in water are also different. In most cases, it is often mixed with other wastewater, so a single method of treatment is often ineffective. At the same time, due to the limitations of various methods, in practical applications, two or three methods are usually used in combination to ensure that the effluent quality meets the discharge standards.
In addition, the different production methods, environmental requirements, and water treatment purposes of each oilfield result in significant differences in oilfield wastewater treatment processes.
In these processes, common primary treatments include gravity separation, flotation, and centrifugal separation. Mainly remove floating oil and oil wet solids; Secondary treatment includes filtration, coarsening, chemical treatment, etc., mainly for demulsification and removal of dispersed oil; Deep processing includes ultrafiltration, activated carbon adsorption, biochemical treatment, etc., mainly to remove dissolved oil.
When treating refinery wastewater, coal based columnar activated carbon adsorbs substances with the advantage of hydrocarbons.
However, in the treatment of refinery wastewater, due to the variety of adsorbed substances in the water, it is relatively complex. In refineries, process wastewater or oily wastewater is a common treatment target. This type of wastewater contains floating oil and suspended substances, and direct treatment with activated carbon is not suitable.
Therefore, in the process of refinery wastewater treatment, it is necessary to use coagulation sedimentation, coagulation pressure flotation, sand filtration, and a combination of methods for pretreatment. On the basis of removing oil and suspended matter first, activated carbon treatment is more effective.
But sometimes when the BOD value is high or the BOD/COD ratio is high, coagulation and filtration methods may not be necessary for pretreatment. However, it is necessary to combine the coal columnar activated carbon adsorption method with the chemical treatment method of activated sludge as the best method.
https://www.naturecarbon.com/wood-based-activated-carbon/columnar-activated-carbon.html
