SU833577A1 - Method of biochemical purification of waste water - Google Patents

Description

The invention relates to methods for wastewater treatment and can be used for aerobic biochemical treatment of domestic and industrial wastewater. ^uh

A known method of biochemical wastewater treatment with activated sludge, in which the compaction of excess activated sludge is carried out in flotation sludge compactors £ 1]. ^υ

However, this method did not find application, since its technical and economic indicators are low.

Closest to the proposed one is a method of aerobic biochemical treatment of wastewater with activated sludge, in which the pre-clarified wastewater enters aeration facilities, where they are intensively mixed with 2Q circulating activated sludge, while saturating the obtained sludge mixture with oxygen. In the presence of oxygen, activated sludge destroys the contaminants contained in the wastewater, * 5 gallon of this part of the contaminants is spent on an increase in the biomass of activated sludge, forming excess activated sludge. The aerated sludge mixture is fed for clarification to the secondary settling tanks, 30 where the sludge mixture is separated into purified water and activated sludge. The purified water is diverted from the biochemical treatment facilities, and the delayed activated sludge is divided into circulating, returned to the aeration facilities for treatment of new wastewater inflows, and excess water, sent after compaction for subsequent treatment. Compaction of excess activated sludge is carried out in gravity sludge compactors, in which sludge is deposited to the bottom under the influence of its own weight, giving up part of the water contained in it. Released ilovukg water is returned to the aeration facility for re-treatment [2].

The disadvantage of this method is the high cost of wastewater treatment due to an increase in the biochemical and hydraulic load on the aeration structure with silt water returned from the sludge compactor. .

The purpose of the invention is to reduce the cost of wastewater treatment.

This goal is achieved by the fact that in the known method biochemistry. Wastewater treatment with activated sludge, including their preliminary active supply of clarification, aeration with the addition of circulating activated sludge, secondary clarification with the separation of purified water and activated sludge, and gravitational compaction of excess activated sludge, the excess activated sludge fed to the compaction is saturated with oxygen, preferably in an amount of 70-100 mg / L.

Saturation of excess sludge with oxygen before its compaction prevents anaerobic processes in the sludge compactor, eliminating secondary contamination of sludge water, and therefore, the cost of its treatment, exceeding the cost of oxygen treatment of excess activated sludge.

Example. After the initial sedimentation, wastewater with an average flow rate of 2000 m ³ / h, having a BOD _{POLY of} 500 mg / l, an oxygen content of 0.00 mg / l and an oxygen consumption rate of 25 mg / g of sludge per hour, is fed to aeration, where they are mixed with circulating activated sludge, maintaining its dose in the sludge mixture of 2.5 g / l. After 11 hours of aeration, the sludge mixture is subjected to secondary clarification for 1.5 hours. Purified (clarified) water characterized by _POAI BOD of 15 mg / l, suspended solids of 15 mg / l, oxygen content of 0.5 mg / l at a consumption rate oxygen 3.0 mg / g sludge per hour, divert outside the biochemical treatment facilities. The activated sludge formed in the process of aeration of the sludge mixture (biochemical wastewater treatment) and delayed by secondary clarification is divided into circulating sludge, providing the required dose of sludge in the sludge mixture (2.5 g / l), and excess Excess activated sludge, characterized by an increase 270 g / m ^{3 of} purified sewage, dry matter content of 4 g / l (humidity 99.6%), ash content of 30%, with a flow rate of 135 m ^? / h is fed into the sludge compactor, after holding it for 10 min under a pressure of 1.6 atm jb in a pressure tank for dissolving the introduced pure oxygen in the amount of 18.9 g / kg dry matter of activated sludge, i.e. 10.3 south / h, providing an oxygen concentration of 75.5 mg / l in compacted sludge. After 9 hours of gravitational compaction. of excess activated sludge sludge water having a _POAI BOD of 15 mg / l, suspended solids 15 mg / l, oxygen content 0.5 mg / l, with a flow

108 m ’/ h is diverted outside the biochemical wastewater treatment plant along with purified water after secondary clarification. Sealed excess activated sludge in an amount of 27 m ^ / h with a dry matter content of 20 g / l is sent for treatment together with other sediments.

Reducing operating costs for electricity provides the effect of 7.23 thousand rubles per year per 1000 kg / h of pollution.

Claims (2)

This invention relates to wastewater treatment methods and can be used with. aerobic biochemical purification of domestic and industrial wastewater. The known method of biochemical treatment of wastewater with activated sludge, in which the compaction of excess activated sludge is produced in flotation sludge compactors 1. However, this method has not found application, since its technical and economic indicators are low. The closest to the proposed method is an aerobic biochemical treatment of waste sewage sludge, in which the pre-clarified sewage enters the aeration facilities, where they are intensively mixed with the circulating sludge, simultaneously saturating the sludge mixture with oxygen. In the presence of oxygen, active IT destroys the contaminants in the wastewater, and in this part of the contamination consumes the activated sludge biomass gain, forming excess active oil. Aerated sludge mixture prepares for clarification to secondary sedimentation tanks, where the sludge mixture is separated into purified water and active sludge Purified water is diverted from biochemical purification facilities, and delayed activated sludge is divided into circulating, returned to aeration facilities for purification of new wastewater inflows, and excess, sent after compaction, for subsequent processing. Excess activated sludge is compacted in gravitational silt compactors, in which sludge is deposited on the bottom by the action of its own weight, giving up part of the water contained in it. The separated sludge water is returned to the aeration facility for re-treatment 2. The disadvantage of this method is the high cost of wastewater treatment by increasing the biochemical and hydraulic load on the aeration facility with the sludge returning from the sludge compactor. . The purpose of the invention is to reduce the cost of wastewater treatment. The goal is achieved by the fact that in the known method of biochemistry. sewage treatment with activated sludge, including their preliminary clarification, aeration with the addition of circulating active sludge, secondary clarification with separation of treated water and activated sludge, and gravitational compaction of excess active sludge supplied to the compaction excess active sludge is saturated with oxygen, preferably in an amount 70-100 mg / l. The saturation of excess activated sludge with oxygen before it is fed to the compaction prevents the development of anaerobic processes in the sludge compactor, eliminating secondary contaminants of sludge water, and, consequently, the cost of its purification, which exceeds the cost of oxygen processing of excess activated sludge. Example. After primary sedimentation, wastewater with an average consumption of 2000 MV, having BOD |) (500 mg / l, oxygen content 0.00 mg / l and oxygen consumption rate 25 mg / g sludge per hour, is fed to aeration, where they are mixed with circulating active sludge, maintaining its dose in a 2.5 g / l sludge mixture. After 11 h aeration, the sludge mixture is subjected to secondary clarification for 1.5 h. Purified (clarified) water, characterized by BOD parameters, mg / l, suspended matter content 15 mg / l, oxygen content 0.5 mg / l at a rate of oxygen consumption of 3, O m g / g sludge per hour, diverted out of the limits of biochemical purification facilities. The sludge mixture formed during aeration (biochemical treatment of waste water; water) and the sludge used in secondary clarification is divided into circulating; providing the required sludge dose in the sludge mixture C2,5 g / l}, and excess Excess activated sludge, characterized by 270 g / m of treated wastewater, dry matter content of 4 g / l (moisture content 99.6%), ash content 30%, with a flow rate of 135 MV4 is fed to the seed compactor , having tentatively sustained it for 10 minutes under the pressure of 1.6 atm. JB An ore tank for dissolving the introduced pure oxygen in the amount of 18.9 g / kg of dry matter of activated sludge, i.e. 10.3 kg / h, providing an oxygen concentration in compacted sludge of 75.5 mg / l. After a 9-hour gravity compaction, no excess activated sludge, sludge water having a BODfilled mg / l, suspended solids 15 mg / l, oxygen content 0.5 mg / l, with a flow rate of 108 m / h is diverted beyond the limits of biochemical purification wastewater together with purified water after secondary clarification. The compacted excess activated sludge in an amount of 27 with a dry matter content of 20 g / l is sent for treatment together with other sediments. . Reducing operating costs for electricity provides the effect of 7.23 thousand rubles. per year per 1000 kg / h of contamination. Claims 1. Method of biochemical wastewater treatment with activated sludge, including pre-clarification, aeration in the presence of circulating activated sludge, secondary clarification with separation of purified water and activated sludge and gravitational compaction of excess activated sludge, characterized in that in order to reduce the cost cleaning, before compaction, excess activated sludge is saturated with oxygen. 2. Method POP.1, characterized by the fact that excess activated sludge is saturated with oxygen in the amount of 70-100 mg / l. Sources of information taken into account during the examination 1. A. Matsnev. Wastewater treatment by flotation. Kiev. Budi Velnik, 1976, p. 45, 106-112. 2. Yakovlev. et al., Sewer, M., Stroyizdat, 1976, p. 353-373,402-406.