SU1127848A1 - Method for treating precipitates of waste liquors - Google Patents

Abstract

1. METHOD FOR TREATMENT OF WASTEWATER DRAINAGE, including aerobic stabilization of primary sludge and compacted excess activated sludge, dehydration, recycling of fugate, about tl and h ay and s. By the fact that, in order to improve the water recovery properties of sediments by increasing the oxidative activity of excess activated sludge, the centrifuge is preliminarily subjected to electro-flotation compaction, mixed with aerobically stabilized sludge and recycled to the dewatering stage. 2-. A method according to claim 1, characterized in that the electrofloat compaction of the centrifuge is carried out to a concentration of 40-50 kg / m. 3. Method 1 and 2, so that excess activated sludge is compacted by electroplating to a concentration of 40-50 kg / m. 4. The method according to claim 1, characterized in that the aerobic stabilization of the primary sludge and compacted excess active or is carried out at a mixture concentration of 4050 kg / m3. N9 M // 00 4: 00 / J / 2

Description

The invention relates to methods for treating sewage sludge and may be used for treating primary sludge and excess activated sludge. The known method of sewage treatment consists in precompaction of excess activated sludge, its aerobic stabilization with primary sludge, compaction of stabilized sludge and excess active sludge, centrifugation of the stabilized sludge with feedstock feed to the biological purification stage or primary sedimentation of Cl3. The disadvantage of this method is oxidative activity of excess sludge, due to lack of oxygen and the occurrence of anaerobic conditions in the layer of thickened sludge during long-term gravitational compaction for 6–8 h. When excess active sludge is compacted under gravity conditions, aerobic stabilization in the initial aeration period (t-2 days) proceeds with the recovery of the oxidative activity of excess sludge microorganisms, which leads to reducing the oxidation of the organic part of the sludge; and the thickening of the moisture-absorbing properties of the stabilized mixture of sludge and sludge. The closest to the proposed technical essence is the method of treating sewage sludge, which consists in aerobic stabilization of a mixture of primary sludge and excess activated sludge, compaction of aerobic-stabilized sludge flotation, dewatering sludge sludge by centrifuging and recycling the fugate to aerobic stabilization stage 2 The disadvantage of the known method is the recycling of the centrate to the aerobic stabilization stage, which leads to an increase in the organic load on the aerobic stabilizer and derestimation organic portion sludge decay. Returning a fungate to the aerobic stabilization stage results in a decrease in the concentration of the mixture and, consequently, a decrease in the amount of heat available during biological oxidation, which results in a decrease in the temperature of the mixture and the degree of decomposition of the organic part of the sediment. Prolonged aerosol scavenger in an aerobic stabilizer results in the dispersion of the solid phase contained in it, impairing the moisture recovery of sediment and the quality of sludge water removed from the sludge compactors. In addition, flotation compaction of a stabilized mixture of nepBH4Hofo sediment, excess activated sludge and centrifuge requires large volumes of flotation silt compactors, high pumping power to saturate the mixture with air, i.e. large capital and operating costs. The purpose of the invention is to improve the moisture-reducing properties of sediments by increasing the oxidative activity of excess activated sludge. The goal is achieved in that according to the sewage sludge treatment method, including aerobic stabilization of primary sludge and compacted excess activated sludge, dehydration, recycling of the centrate, the latter is preliminarily subjected to electro-flotation compaction, mixed with aerobic-stabilized sludge and recycled to the dehydration stage. Electrofloat compaction of the centrifuge is carried out to a concentration of 4050 kg / m. Excess activated sludge is compacted by electroflotation to a concentration of 4.050 kg / m. Aerobic stabilization of the primary sediment and compacted excess active staff is carried out at a mixture concentration of 40-50 kg / m. I. The centrifugal aerobic-stabilized mixture has a concentration of 25-30 kg / m. Electroflotation compaction thereof to a concentration of 40-50 kg / m contributes to the intensification of the sludge treatment process by 3-4 times, improves their sedimentation properties and, therefore, moisture return, which ultimately leads to an increase in centrifuge productivity, the mixing of a compacted centrifuge with a stabilized mixture of primary sludge — and excess sludge precludes its delivery to the aerobic stabilization stage, which leads to a decrease in the organic load of one hundred ilizator 1.5-2 times, prevent pulverization of solids and favorably affects the process of dewatering the mixture. 3 Pre-electroflotation compaction of excess activated sludge accelerates the thickening process, increases the concentration of compacted activated sludge, and intensifies the aerobic stabilization process, which is achieved due to an increase in the oxidative activity of excess sludge, since the microbubbles of oxygen released during electro-flotation are constantly observed. compacted sludge and thereby prevent the occurrence of anaerobic conditions. Due to the high rate of compaction of excess sludge, the volume of the flotation cell is significantly reduced. The high5 concentration of the mixture in the aerobic stabilizer (40-50 kg / m) provides a more intensive heat release of biological oxidation and maintain higher temperatures in it, which increases the degree of decomposition of the organic part of the sediment. The concentration of the mixture less than 40 kg / m in the stabilizer does not allow maintaining the necessary temperature in it, since it reduces the decomposition of the organic part of the mixture and increases the duration of stabilization, requires subsequent compaction of the mixture before centrifugation, and a concentration more than 50 kg / m complicates aeration in the stabilizer, increases the energy consumption for aeration and the supply of the stabilized mixture to the centrifuge, due to the fact that it is very difficult to keep the mixture biomass in suspension. Due to the high concentration of the mixture in the stabilizer, it is not necessary to consolidate it before dehydration in order to increase the effect of holding the solid phase by centrifuges. The absence of seals and an increase in the productivity of centrifuges contributes to a significant reduction in costs. Preliminary compaction of excess activated sludge to a concentration of 40-50 is achieved within 0.75-1 hours, at a current density of 3050 A / m. The concentration of compacted sludge less than 40 kg / m does not ensure that the concentration of the mixture in the stabilizer is 40-50 kg / m, and more than 50 adversely affects the process of aerobic stabilization. 484 The technological scheme of the proposed method for treating sewage sludge is shown in FIG. 1. The scheme contains an electroflotation compactor 1, equipped with pipelines for supplying excess activated sludge 2, removal of sludge water 3 and supplying compacted sludge 4 to the aerobic stabilizer 5, to which the primary sludge pipeline 6 is connected. Aerobic stabilizer 5 is separated by a partition 7 with a window from the mixing chamber 8 connected by pipelines for supplying compacted centrifuge 9 and removal of stabilized mixture and centrifuge 10 to centrifuge 11. The centrifuge is equipped with pipeline 12 for removing cakes and electroflotation sealer 14 for centrifuge, , the latter is connected by a pipeline for supplying a compacted centrifuge with a chamber 8mixing and a pipeline 15 for supplying sludge water, into pipeline 16 for returning sludge water to the stage of biological treatment, where it is connected also the pipeline 3 removal of sludge water from the electro flotation sealer 1. The method is carried out as follows. Excess activated sludge with a concentration of 4-6 kg / m by pipeline 2 is fed to an electro flotation seal 1 and sealed to a concentration of 4050 kg / m. Compacted sludge pipeline 4 is obtained in an aerobic stabilizer 5, which simultaneously serves the primary sediment concentration of 4050 kg / m pipeline 6 and the mixture is aerated for 4-5 days. The stabilized mixture through a window in the partition 7 is fed into the mixing chamber 8, where simultaneously the pipeline 9 is fed with a fugate compacted to a concentration of 40-50 kg / m in an electroflotation silt compactor 14 and mixed for 0.4-0.5 hours. Mixture from chamber 8 mixes through pipeline 10 are fed to dewatering to a centrifuge 11, from there cake is fed to pipeline 12 for further processing, and the centrate is transferred back to pipeline electro-flotation compactant 14 via pipeline 13, where it is compacted to a concentration of 40-50 kg / m for 0.75-1 h, at a current density of 35-50 A / m. Sludge water from electroflotation packagings 1 and 14 are also available from {1 irjBeiiicf r.5 solids 20-30 μG / m and VPK 3050 μG / cm pipelines 3 and 15 are fed to the general pipeline 16 and fed for reprocessing to the stage biological treatment. Example. Excess activated sludge with a concentration of 6 kg / m is compacted by electroflotation to a concentration of 50 kg / m for. 1 h. IIjiH with a current of 35 A / m compacted excess activated sludge is subjected, together with a primary precipitate with a concentration of 50 kg / m, to aerobic stabilization for 5 s. The stabilized mixture is intensively mixed with a fug atom compacted by electro-flotation to a concentration of 50 kg / m for 0.5 They are dehydrated on the 8th centrifuge, the cake with a humidity of 65-70% is fed for further processing, and the centrifuge with a concentration of 25-30 g / m is fed to the electro flotation compaction. Sludge water from the dust collectors is supplied to aerotanks. Comparative technological indicators of the known and proposed methods are shown in the table. Thus, the proposed method allows to obtain a stabilized, non-rotting precipitate with good moisture-retaining properties, increase the degree of decomposition of the organic part, eliminate compaction of the stabilized mixture, and reduce costs.

Consumption of excess sludge concentration of 6 kg / m

Consumption of primary sludge with a concentration of 50 kg / m Duration of compaction of excess sludge, h

The volume of the sludge compactor,

Consumption of compacted sludge

Concentration of compacted sludge, kg / m

Volume of aerobic stabilizer, m

Volume of sealers fugata, m

The decay of the organic part,%

Resistivity of stabilized sm filtration U m / kg

800 96

one

50

96

50.0. 960 8 20-28

30-50

Technological indicators

Number of centrifuges

Long centrifugation, h

The effect of delaying the dry matter of the mixture,%

1127848

8 Continuation of the table

Way

proposed

famous

I

.2

sixteen

12

42-45

45-48

Claims (4)

1. METHOD FOR WASTE WATER SEDIMENTS TREATMENT, including aerobic stabilization of primary sludge and compacted excess activated sludge, dehydration, centrifugal recirculation, sludge s. I mean that, in order to improve the water-giving properties of sediments by increasing the oxidative activity of excess activated sludge, the centrate is preliminarily subjected to electroflotation compaction, mixed with aerobically stabilized sludge and recycled to the dehydration stage. 2 hours Pop Method 1, characterized in that the electroflotation compaction of the centrate is carried out to a concentration of 40-50 kg / m ³ . 3. The method according to π. 1, with the fact that excess activated sludge is compacted by electroflotation to a concentration of 40-50 kg / m ^3. , 4. The method according to p. 1, characterized in that the aerobic stabilization of the primary sediment and compacted excess active or carried out at a concentration of 40- 50 kg / m ³ . „„ SU 1127848> 1 ’1127848