Water features:

Grease industry wastewater usually refers to the wastewater discharged from edible oil refining and processing unit.It mainly includes extraction wastewater,refining workshop hydration wastewater,alkali refining wastewater,cooling water and ground washing water,etc. Different process lead to different pollution loading,COD:2000-7000mg/l,BOD:1500-2500 mg/l,oil:1500-2500mg/l;Wastewater’s grease composition includes suspension oil,emulsified oil,dissolved oil,phospholipids and gleditsia sinensis lam soap.And its suspended matter content is also quite high.Another characteristic of the wastewater is C:N:P ratio is moderate and the biodegradability is good.

According to grease wastewater characteristic,we strengthened the pretreatment stage in actual project,used “oil separation+air flotation” process,oil separation to remove suspension oil,then air flotation to remove emulsified oil;finally using biochemistry to eliminate dissolved oil and major organic matter.Biochemistry process is the key to guarantee sewage standard discharging,at present,“anaerobic-aerobic” process is with better treatment effect.Effluent achieves following standard:COD_cr≤50mg/l,BOD₅≤10mg/l,SS≤20mg/l,NH₃-N≤5mg/l.