RU1813742C - Method of biological treatment of sewage from nitrogen - Google Patents

Abstract

The inventive method for biological treatment of wastewater from nitrogen, including the treatment of wastewater with activated sludge, two-stage sedimentation, nitrogen oxidation and denitrification, sorption of pollution on activated sludge before settling the first stage for 15-20 minutes at an oxygen concentration of not more 0.5 mg / L, after settling of the second stage, the return activated sludge is sent for regeneration, which is carried out to the level of 1.1-1.2 of the rate of endogenous respiration of microorganisms. 1 tab.

Description

The invention relates to the field of wastewater treatment, in particular to a method for removing nitrogen from wastewater and can be used in biological treatment plants.

The purpose of the method is to accelerate the process and increase the degree of purification of wastewater from nitrogen.

This goal is achieved in that in a method for biological treatment of wastewater from nitrogen, including treatment of wastewater with activated sludge, two-stage sedimentation, nitrogen oxidation and denitrification, sorption of pollution on activated sludge is carried out before settling the first stage for 15-20 minutes and concentration oxygen not more than 0.5 mg / l; after settling of the second stage, the return active ml is sent for regeneration, which is carried out to the level of 1.1-1.2 of the endogenous respiration rate of microorganisms, while maintaining the age of the sludge.

The proposed method allows to reduce the total transit time of all processes to 6.0-8.0 hours and to obtain a residual nitrogen content in the treated effluent in an amount of less than 1 mg / l, which corresponds to a high degree of wastewater purification from nitrogen-90%.

The drawing shows a flow chart of the proposed method. Wastewater after mechanical treatment facilities 1 enters the sorption chamber 2 aerated by air 19, where regenerated activated sludge 18 enters at the same time, on which pollution from the wastewater is adsorbed. A mixture of sludge with wastewater 3 enters sump 4, where it is gravitationally separated into water 5 and sludge 6. Water is supplied to a nitrifier 7, which is a biofilter structure with attached microflora, purged with oxygen enriched air 9, and activated sludge with sorbed it is contaminated with 6 into the denitrifier 8, where the nitrified runoff from the nitrifier is also directed. A denitrifier is an aerotank type structure that is purged

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oxygen depleted air 10. The mixture of sludge with water 11 from the denitrifier enters the sump 12, where it is gravitationally separated into purified water 13, discharged into the river or into subsequent treatment facilities, and into activated sludge 14, which is divided into return 15 and excess 16. Return sludge is sent to a regenerator 17, where they are aerated with air 19, and excess sludge is sent for treatment or disposal.

Example. Wastewater consumption 5000 m3 / h or 100000 m3 / day. The quality of the initial water - BOD5 150 mg / l, nitrogen of ammonium salts 30 mg / l. The quality of the purified water - BOD 10 mg / l, the removal of suspended solids 10 mg / l, the sum of the forms of nitrogen less than 2 mg / l. The volume of the sorption chamber is 1666 mg. The oxygen concentration is 0.5 mg / l, the air flow rate is 3.0 m / m ..h, Sorption is 75% of BOD when passing through the sorption chamber.

Intermediate sedimentation tank - torn 1 h, volume 5000 m3.

Aeration tank-nitrification - total volume 7500 m3, nitrogen load 470 g. N-NH4 / M3 charge per day, aeration with air in the amount of 175000 m3 / h. Denitrifier - Volume

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5

0

5

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14500 m, tg - 2.9 h. Sludge with adsorbed organics and nitrified runoff are fed.

The volume of the regenerator to achieve a breathing rate of 1.2 V3nn is 1500 m.

Air consumption 3.5 m / m.h. Sludge separation in a secondary settling tank with a volume of 10,000 m3. The total volume of structures is 40,166 m3. Air consumption 19550 m3 / h.

The table presents specific data confirming the effectiveness of the method, as well as comparative data with the prototype.

Claims (1)

The formula is a method of biological treatment of wastewater from nitrogen, including treatment of wastewater with activated sludge, two-stage sedimentation, nitrogen oxidation and denitrification, characterized in that, in order to accelerate the process and increase the degree of purification from nitrogen , before settling of the first stage, sorption of pollution on activated sludge is carried out for 15-20 minutes and the oxygen concentration is not more than 0.5 mg / l, after settling of the second stage, the return activated sludge is sent to regeneration, which is carried out to the level of 1.1 -1.2 en speed ogen respiration of microorganisms.