SU1662953A1 - Method of processing sewage sludge - Google Patents

Abstract

The invention relates to the treatment of sewage sludge by biothermal processing and can be used in waste treatment plants for dewatering and composting solid household waste and sewage sludge. The aim of the invention is to increase the yield of compost and reduce the cost of the process. In the method of treating sewage sludge, including dewatering, biothermal processing together with solid household waste in horizontal rotating bio-drums, sorting, grinding and composting in piles, the sediments after dehydration are divided into two streams, one of which is fed to the bio-thermal treatment in bio-drums in a mixture with municipal solid waste with a rotation rate of bio-drums of 1.0-1.5 min ^-1 , the resulting product, after sorting and grinding, is mixed with another stream of dehydrated sediments in a mass flow In the ratio of 2: 1-3: 1 for 20-36 hours, and the composting is carried out for 30-60 days with one-time stirring. 2 hp ff, 5 tab.

Description

The invention relates to the treatment of sewage sludge by biothermal processing and can be used in waste treatment plants for dewatering and composting solid household waste and sewage sludge.

The aim of the invention is to increase the yield of the compost and reduce the cost of the process.

The method is carried out as follows.

Mechanically dewatered (or dried on sludge grounds) sewage sludge (WWS) with a humidity of 75-80% is subjected to biothermal processing together with municipal solid waste (MSW), while the dewatered WWS is divided into two streams, one of which together with MSW served in horizontal rotating bio-drums at a mass ratio of MSW: WWS 2: 1-3: 1.

The mixture is subjected to biothermal processing for 20-36 h (20-28 h at

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positive and 28-36 h at negative ambient temperature) at a bio drum speed of 1-1.5 minutes. During this time, the material is homogenized and its partial abrasion, thermophilic aerobic microorganisms reach the phase of maximum biological activity, the temperature of the mixture rises to 45-50 ° C,

After unloading from the drum, sorting (for the purpose of extracting ballast impurities) and crushing, the resulting product is mixed with another WWS stream in a mass ratio of 2: 1-3: 1 and the mixture is composted in single-mix piles for 30-60 days.

At the first stage of processing, a non-neutralized homogenized product based on MSW and WWS (GPTO) is obtained, which has high biological activity. It cannot be used either as a biofuel or as compost, since it does not go beyond the necessary stages of neutralization and mineralization of organic matter. Due to the high bioenergy potential when ripening in piles in the GPTO, the process of thermogenesis is intensively developed, which allows composting an additional amount of sediment in the mixture with it.

After a constant rotational speed of 1-1.5, the required number of revolutions (1500) the bio-drum makes respectively for 24-17 hours, while providing the necessary level of activity of thermophilic microorganisms, determined by raising the temperature of the mixture to 45-50 ° C.

When processing the mixture at low rotational speeds, the temperature in the bio drum does not reach 50 ° C and the necessary conditions for the active development of thermophiles are not provided even after 72 hours of processing.

The effect of the processing time of a mixture of MSW and WWS in bio-drums on its temperature is given in Table. one.

Comparison of the proposed method (with a different number of WWS, fed to composting) with the prototype is given in table. 2

As can be seen from the table. 2 data, in all piles, except for piles with a 1: 1 mixing ratio, the entire mass of the composted mixture was heated to a temperature of 50 ° С 30 days after laying. And in stack 5, even after 60 days, the neutralization temperature was not reached. Sanitary assessment of such compost

showed the presence of viable helminth eggs in it and a low titer of CoM. Thus, with a 1: 1 ratio of HHPT and sediment, the required level of decontamination of the mixture is not ensured.

The upper limit of the ratio of the components to be mixed is determined by the economic feasibility of the process, and the process is more economical than a larger amount of sediment can be disarmed together with the MSW.

With a mixing ratio of 4: 1, an additional 70% of the remaining residue is neutralized. At a ratio of 3: 1, the entire sediment is neutralized. The compost obtained after ripening on piles meets the requirements for compost from MSW (TT) and can be used as a valuable organic fertilizer.

The proposed method makes it possible to neutralize and process 3-4 times more sediment than by the known method of combined bio-thermal treatment of solid waste and 5 WWS in bio-drums, to increase the productivity of waste processing plants for processing solid waste by 2 times, and without composting additional installation of the main equipment - 0 ni.

Comparative analysis of the known and proposed methods for joint biothermal processing of MSW and WWS is given in Table. 3

5Example Joint biothermal

processing is subjected to a mixture of MSW in Minsk with an average humidity of 48% and a mechanically dehydrated sludge from the Minsk aeration station with a humidity of 77%. A mixture of waste in 0 ratio MSW: WWS 2.5: 1 is loaded into the KM-101A bio drum (d 4 m, I 36 m). . The mixture is processed at a bio drum drum speed of 1.0 min 1 for 20-36 hours. After the bio drum has reached a temperature of 45-50 ° C, the mixture is discharged, sieved on a cylindrical screen HZ-05 and crushed in a crusher KM-001-1 . The obtained homogenized product is mixed with an additional amount of 0 mechanically dehydrated sludge in the ratio GPTO: WWS 2: 1 and the mixture is placed in piles 2.5 m high with natural aeration. After the temperature reaches 50 ° C in the stack, a one-time mixing of the composted mass by the universal loader D-565 is performed.

The results of biothermal treatment of WWS with MSW by the proposed method are given in table. 4. The resulting compost is practically the same as compost from MSW alone.

The main indicators of the quality of compost are given in table. five.

As the data show, the compost obtained as a result of joint processing of MSW and WWS according to the proposed method meets the basic requirement for compost produced by waste treatment plants.

Claims (3)

1. A method for treating sewage sludge, including dewatering, biothermal processing together with solid household waste in horizontal rotating bio-drums, sorting, shredding and composting into piles, characterized in that In order to increase the compost yield and reduce the cost of the process, the sludge after dehydration is divided into two streams, one of which is fed to the bio-thermal treatment in bio-drums mixed with solid household strokes at a bio-drum rotation speed of 1.0-1.5 min. mixed with another stream of dehydrated precipitation in a mass ratio of 2: 1-3: 1. 2. A method according to claim 1, characterized in that the treatment in bio-drums is carried out at a mass ratio of solid household waste: dehydrated precipitates 2: 1-3: 1 in for 20-36 h 3. Method according to claims 1 and 2, from t and h and yusch y- so that composting is carried out for 30-60 days with one-time mixing. T a b t and c a 1 Ratio of GPTO and OSV added to it The humidity of the mixture coming to composting, 7 1 1: 0 (prototype) 54-56 4: 1 3: 1 2: 1 1: 1 58.6-60.2 59.7-61.0 61.7-63.0 65.5-66.5 thirty 30 30 30 60 52-67 51-67 52-71 52-68 32-46 Ots „ 0.01 Unveiled (neutralized not secured) 0.01 0.01 0.01 0.001 70 100 150 300 Meets technical requirements (TT) for MSW compost Also Does not meet the TT for the degree of neutralization from sg YU CD U1 CJ oo The number of bio drum KM-101A (4x36m) 4 The number of recycled MSW thous.t / year90 The ratio of MSW and WWS in the process of bio-thermal processing of waste in bio-drums (at a mixture humidity of 60%) 2: Duration of processing mixture MSW and WWS in bio drums, h48 The amount of WWS processed in biob tabans, thousand tons / year45 The amount of homogenized product based on MSW and WWS (GPTO), arriving at the maturation sites (including non-compostable waste in the amount of 30% Fri mass MSW and losses moisture when sifting, crushing and transportation in the amount of 8% of initial waste moisture). ten Ratio GPTO. WWS Additional amount of sediment disposed of in the second stage of processing Compost yield, kt / year75 Cost of compost, rub./t 16 The number of neutralized WWS, ths t / year45 Indicators Ambient temperature, С The number of TCO loaded into the bio drum, t The amount of WWS loaded into the bio drum, t The content of organic matter in the mixture,% dry weight The rotation speed of the bio drum, Duration of processing a mixture of MSW and WWS in a bio drum, h Table 3 180 2: 1 24 90 200 2.5: 1 80 190 12.0 170 Table 4 Example ) - (+ 25) (+6) - (+ 8) 120 50 60 1.0 24 (-10) - (- 12) 120 50 64 1.0 36 Organic matter content in a homogenized product, % dry mass64 Additional number of AOS, mixed with a homogenized product based on MSW and WWS, t55 Duration of disposal in piles, sut30 Temperature of compostable mixture in stacks, С: after 20 days 45-5 after 30 days 55-6 after 60 days. Decomposition of organic matter during composting the mixture in piles,% 13.2 eskohoy % % % 43-45 0.67-0.69 48.3-54.3 1.90-2.10 0.58-0.63 0.38-0.45 0.1 7.1-7.5 Continued table. four 64 55 60 41-50 47-55 53-62 18.0 Table 5 45 40 1.60-1, 8 0,29-0, 5 0.50-0, 4 0.1Ј0.01 6.2-6.8