METHOD FOR BIOLOGICAL TREATMENT OF WASTEWATER FROM LIGHT HYDROCARBONS Russian patent published in 2021 - IPC C02F3/30 C02F101/32 

FIELD: biological wastewater treatment.

SUBSTANCE: invention relates to the field of biological wastewater treatment containing light hydrocarbons, including ethylene glycol, and can be used for the treatment of industrial wastewater, industrial drainage wastewater, surface wastewater, for example, from the territory of airports. Mechanically treated wastewater is sent to the sludge system of the bioreactor-displacer of the first stage of biological treatment, which contains three sludge systems in series. The first sludge system is characterized by oxygen deficiency, oxygen concentration of no more than 0.5 mg/l, a light hydrocarbon load of 2.5 to 1.0 kg per 1 kg of biocenosis for ashless substance per day and the formation of a predominantly anaerobic biocenosis. The second sludge system is characterized by oxygen concentration of 1.0 to 2.0 mg/l, a light hydrocarbon load of 1.2 to 0.3 kg per 1 kg of biocenosis for ashless matter per day and the formation of an aerobic-anaerobic biocenosis. The third sludge system is characterized by concentration of dissolved oxygen from 3.0 to 5.5 mg/l, a light hydrocarbon load of 0.3 to 0.06 kg per 1 kg of biocenosis for ashless substance per day and the formation of an aerobic biocenosis. The recirculated sludge liquid from the third sludge system is fed to the beginning of the first sludge system in an amount of 100-200% of the total volume of incoming waste water. The total residence time of waste water at the first stage of biological treatment is from 4.0 to 24.0 hours. From the bioreactor-displacer of the first stage of biological treatment, the sludge liquid is fed into a secondary settler with thin-layer settling modules, the settling time is set from 0.5 to 1.0 h. The settled waste water is fed into the fourth sludge system of the second-stage bioreactor-displacer with an oxygen concentration of 3.0 to 5.5 mg / l and a load of light hydrocarbons from 0.1 to 0.01 kg per 1 kg of biocenosis for ashless substance per day, with the formation of an aerobic biocenosis. Then the wastewater is subjected to two-stage filtration, at the first stage it is filtered through a brush load at a filtration rate of 5.0-10.0 m / h and at the second stage of filtration through a fine disc filter.

EFFECT: invention improves the degree of wastewater treatment from light hydrocarbons and the stability of the biological treatment process.

3 cl, 3 dwg, 1 tbl