SU1439090A1 - Method of treating waste water sediments - Google Patents

Abstract

The invention relates to methods for treating sewage sludge and can be used in biological and sewage treatment plants for domestic and industrial wastewater. The purpose of the invention is to reduce the humidity and resistivity of filtration of compacted fermented sediment and reduce the concentration of contaminants on suspended substances and BOD in the drain, water and filtrate. For this, in the method of treating sewage sludge, including. compaction of excess activated sludge followed by anaerobic digestion together with sediment from primary settling tanks, washing the fermented sludge with biochemically purified, oxygenated water, recycling part of the compaction products, saturated with oxygen, into the sediment, flushing the mixture of fermented sludge and washing water with compaction of the washed fermented sludge, addition of reagents to the compacted sludge, mechanical sludge dewatering, mixing and recirculation of the filtrate and drainage water to Structures, a mixture of fermented sediment and biochemically purified wash water are blown with air in a thin layer, passed through a layer of flooded porous load with countercurrent air blowing, before compaction the washed sediment is mixed with part of the compacted recycled sludge, drain water is mixed with filtrate, passed through a layer of porous load with countercurrent air blowing, recycle them to excess activated sludge and compacted with excess active sludge before its anaerobic digestion eat. Before compaction, the preliminarily washed precipitate should be mixed with the part of the compacted sludge in a ratio of 1: (O, 05-0.2) by weight of dry matter and at a speed not exceeding 0.2 m / s, and excess active water should be passed through the bed riser load after adding a mixture of drain water and filtrate to it. 2 hp f-ly, 1 ill. 1 tab. & (П с: h Сдд; о

Description

The invention relates to methods of treating sewage sludge and can be used at the stations of biological treatment of domestic and industrial sewage.

The aim of the invention is to reduce the moisture content and resistivity of the filtration of compacted fermented sludge and decrease the concentration of contamination by suspended matter and MIC in the discharge water and the filter. those.

; The drawing shows a flow chart of the method.

The scheme contains pipeline 1 supply of excess activated sludge, i-seal 2, pipeline 3 compacted activated sludge, pipeline 4 sludge water, pipeline 5 sediment of primary settlers, methane tank b, pipeline 7 of fermented sludge, pipeline 8 biochemical cleaned wash water, pipeline 9

for 10–20 s, at a height of 0.05–0.2 m on the perforated bottom of the layer and passed through a layer with a porous charge with countercurrent air blowing and then bubbled with compressed air for 0.25–1.0 h. tank sludge and wash water mixture is fed into

0 shockulor 13, where within 0.1-. 0.2 h and at a speed not basshee0,2 m / s mixed with saturated oxygen recirculated compacted sediment, then the mixture is sent to the precipitation box 15, made with a device for smooth mixing. Compaction of industrial fermented sludge is carried out within 12-18 hours, depending on the mode of digestion.

20 draft.

The compacted sludge, after adding ferric chloride and lime to it, is sent to mechanical dewatering 21, after which the compressed air is exhausted, mixer 10, pipe 25, the dried sludge is removed from the waste.

wire 11 of the mixture of fermented sediment and wash water, wash tank 12, flocculator 13, oxygen-recirculated compacted sludge line 14, precipitator 15, compacted sludge pipeline 16, recirculated sludge pipeline 17, oxygenator 18, ferric chloride supply pipe 19, lime supply pipe 20, mechanical sludge dewatering 21, dehydrated sludge pipeline 22, filtrate pipeline 23, drain water pipeline 24, mixer 25, filtrate and drain water mixture pipe 26, coagul Op 27.

The process is as follows.

Compacted surplus sludge and sediment from primary sedimentation tanks are sent to (methane 6, where they are fermented together. Fermented sludge is fed to the mixer 10, where 2–4 volumes of biochemically purified washing water transported from fermented sediment by bubbling compressed air. From - a mixer, the mixture of fermented sediment and wash water is fed to the wash tank 12, where it is followed, continuously in its movement from top to bottom, blow 10-50 volumes of air into

for 10–20 s, at a height of 0.05–0.2 m on the perforated bottom of the layer and passed through a layer with a porous charge with countercurrent air blowing and then bubbled with compressed air for 0.25–1.0 h. tank sludge and wash water mixture is fed into

0 shockulor 13, where within 0.1-. 0.2 h and with a speed not basshee0,2 m / s mixed with saturated oxygen recirculated compacted sludge, then the mixture is sent to the sludge basin 15, made with a device for smooth mixing. Compaction of industrial fermented sludge is carried out within 12-18 hours, depending on the mode of digestion.

0 draft.

The compacted sludge, after adding ferric chloride and lime to it, is directed to mechanical dehydration 21, after which

five

0

five

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The recirculated compacted sediment is directed from the precipitator to the oxygenator 18, where it is blown with compressed air for 0.1-0.2 hours. The filtrate after mechanical dewatering and the drainage water after the precipitator is sent to the mixer 25, where they are mixed for 0.05-0.1 h with purging with compressed air. Then a mixture of drainage water and filtrate is passed through a layer of flooded porous charge with countercurrent air blowing and sent to coagulant 27 of sludge compactor 2, where it is mixed with excess active sludge and compacted them together for 6-9 hours. Sludge water after sludge compactor is recycled to sewage treatment plants.

Recirculation to compacts of the washed sediment of less than 0.05 and more than 0.2 parts by weight of dry matter of the sediment is impractical, since it does not lead to a decrease in humidity and resistivity of filtraters of the compacted sludge, as well as suspended solids and BOD values. in the drain water.

The velocity of the washed sludge and the recycled part of the compacted sludge should not exceed 0.2 m / s, since at high speeds paspyiiieime flocculation occurs

circulating sludge, which leads to an increase in humidity and resistivity of filtration of compacted sludge, an increase in the concentration of suspended substances and the magnitude of the MIC in the discharge water.

Example 1. Sewage flow rate, supplied to sewage treatment plants, 1000000 m / d, suspended matter concentration 250 mg / l, VPK - 200 mg / l. The digester is calculated on a 6-day digestion of the sediment primary sludge and excess activated sludge. The fermented sediment in a cm-tank is mixed for 0.05-0.1 h with 3 volumes of biochemically purified wash water and the resulting mixture is sent to a wash tank, where it is passed through a layer of 0.10 m at a perforated bottom and rinsed with 20 volumes of air 1 volume of the mixture for 15 s, then passes through a layer of porous loading with a height of 0.05 m with counterflow air blowing and bubbled for 0.5 h with compressed air at an aeration rate of 6 m / m h.

The mixture of fermented sediment and wash water for 0.15 hours in the flocculator is mixed at a stirring speed of 0.034 m / s with 0.1 mass of compacted recirculated sediment, previously saturated with oxygen in the oxygenator for 0.15 h and compacted in for 16 h in the precipitator.

Ferric chloride and lime are sequentially introduced into the compacted sludge and mechanically dehydrated to a moisture content of 75%,

Drain water after sediment packing and the filtrate after mechanical dewatering is stirred for 0.1 h, the mixture is passed through a layer of porous loading 0.5 m high with countercurrent blowing with 10 volumes of air, mixed in a coagulator with excess active sludge for 0.2 hours and sent to a sludge compactor, where excess activated sludge is compacted for 7 hours. Sludge water after the sludge compactor is circulated to the treatment plant.

Example 2. The method carried out under the conditions of example 1 in a similar sequence of operations and values of technological parameters, and

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- 15 th

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Harvesting of fermented fermented rye washing with oxygen with oxygen for a period of, - in: a heating layer of a porous H: hundredth of 2 m.

(1 D example 3). The method is implemented in the example of Example 1, analogous to Example 2, except that the excess active fluids are passed through the heated layer of the porous feed after adding to it a mixture of drainage water and filtrate for 0 , 25 J and t1lot for 6.0 hours.

The indicators characterizing the efficiency of the proposed method for treating sewage sludge in comparison with the known are given in the table. Thus, the use of the pre-selected method of treating sewage sludge allows, in comparison with the known method, to achieve a decrease in the sediment thickness from 96.0 to 94.0-94.5% and the specific resistance of the filtrate.

25 compacted fermented sediment with

1000-10 ° (400-500) cm / g, reducing the concentration of contaminants in recirculated to the wastewater facilities by a known method of draining water and filtrate suspended from 1000 and liOO, respectively, to 80-100 mg / l in peIJ pkvlimer ip water according to the proposed method, Citii produces the value of BOD, which is always from 500 to 40-50 mg / l, which provides savings of capital expenditures for 960-1070 gys. rubles, due to a decrease in the volumes of aerotanks by 11%, sludge thickeners by 10%, methane-tensors

..0 by 12–16%, sedimentation packs by 10–17% and a corresponding decrease in operating costs by 10% due to energy savings for air supply to aeration tanks, heat to methane45 TeHKii and reduction by 25–35% of reagent consumption.

Claims (3)

Invention Formula 1, —The method for treating sewage sludge, including compaction of excess activated sludge followed by anaerobic digestion together with sludge from primary settlers, washing the fermented sludge with biochemically purified oxygen enriched with oxygen, recycling part of the compacted products saturated with oxygen, washed with sludge purge mixtures of fermented sludge and wash water with air, compaction of washed fermented sludge, adding reagents to compacted sludge, mechanical sludge dewatering, mixing filtrate and recycle of filtrate and drain water to sewage treatment plants, characterized in that, in order to reduce humidity and specific filtration resistance, the compacted is reduced sediment and decrease the concentration of suspended solids and BOD in the discharge water and filtrate, the mixture of fermented sludge H of biochemically purified wash water is purged air in a thin layer, pass through;} a layer of a flooded porous load with anti-backwash air, before compaction, wash the sediment mixed with a portion of the compacted recycle sludge, drain water is mixed with the filtrate, pass a layer of flooded porous load with counter-current air blowing through, they are recycled to surplus activated sludge and compacted with excess activated sludge before it is anaerobically digested. 2. A method according to claim 1, characterized in that the washed precipitate before compaction is mixed with the recycled part of the compacted sludge in a ratio of 1; (0.05-0.2) by weight of dry matter and with a mixing speed of not more than 0.2 m / s. 3. Method according to paragraphs. 1-2, characterized in that the excess activated sludge is passed through a bed of submerged porous charge after adding to it a mixture of drainage water and filtrate. PRS "10lk 1gie gabltsm V,