CN104529112B - Sludge organism drying method for treating - Google Patents

Abstract

The invention is a sludge biological drying treatment method utilizing microbial fermentation and drying, which solves the technical problems of high power consumption and serious environmental pollution in existing sludge drying. It is a drying treatment process for fresh sludge with a water content of 76% to 84% after concentration treatment. It includes the following steps: a. Adjusting the water content of fresh sludge; b. Adding bacterial agents; c. Sludge fermentation and drying. The dried sludge after drying treatment can be used in various aspects such as supplementing land. The present invention is a biological drying process that utilizes microbial aerobic fermentation to produce heat to evaporate water, fully utilizes the bioenergy of the sludge itself, and is an economical, energy-saving, and environmentally friendly drying technology; it improves the drying efficiency, shortens the drying cycle.

Description

Sludge Biological Drying Treatment Method

technical field

The invention relates to a treatment technology of sludge, which is a sewage treatment product, in particular to a sludge biological drying treatment method.

Background technique

During the treatment of urban domestic sewage, a large amount of sludge is generated through the process links such as primary sedimentation tank and secondary sedimentation tank. Under normal circumstances, the amount of sludge produced per 10,000 tons of sewage after treatment (based on a moisture content of 80%) is about 6 to 8 tons. The sludge produces a foul smell and contains a large amount of heavy metal elements (such as Cd, Hg, As, Pb, Ni, Cr, Cu, etc.), harmful organic substances (such as benzopyrene, polychlorinated biphenyls) and fecal colon Harmful bacteria such as bacteria and roundworm eggs pose a serious threat to urban environmental pollution.

At present, sludge disposal can be roughly divided into: sanitary landfill, composting land use, lime solidification landfill, anaerobic biogas production and dry incineration. Due to the high water content of municipal sludge, it is still as high as about 80% after concentration and dehydration. It has the characteristics of large volume, unfavorable transportation, and unstable properties. "Landfill" will occupy a large amount of land, and will also produce leachate to pollute groundwater; Instability is difficult to use reasonably; "incineration" has too low calorific value due to low solid content to maintain effective spontaneous combustion and consume a large amount of auxiliary fuel, which significantly increases the disposal cost. Therefore, the drying treatment of sludge is an important part of sludge resource disposal.

The traditional sludge drying is carried out in the sludge drying field, and the sludge is piled up in the outdoor drying field, and the sludge is dried by natural ventilation and gravity. The current drying process is mainly thermal drying and mechanical drying, that is, the water in the sludge is evaporated and squeezed through an external heat source, power supply and related mechanical equipment. The former occupies a large area and has low efficiency; the latter has high investment and operating costs and high energy consumption for equipment operation. Although the domestic and foreign thermal drying sludge drying processes are constantly improving at this stage, such as optimizing heat sources, reducing process steps, and optimizing operating parameters, the characteristics of the process itself (using external heat sources) determine its drying process. Process energy consumption is high.

Contents of the invention

The present invention solves the technical problems of the existing sludge drying (thermal drying) such as high power consumption, high cost, large land occupation, and serious environmental pollution during the drying process, and further provides a sludge drying method using microbial fermentation. Mud biological drying treatment technology.

The sludge biological drying treatment method of the present invention is a drying treatment process of fresh sludge with a moisture content of 76% to 84% after concentration treatment, and it includes the following steps:

a, deployment of fresh sludge water content: the fresh sludge and the base material with a water content of 28% to 32% are stirred and mixed in a weight ratio of 1:1.4 to 1.6 to obtain a mixture;

b. Add bacterial agent: add 2.0‰～2.5‰ of compound bacterial agent to the mixture obtained in step a and mix well to obtain dry material;

c. Fermentation and drying of sludge: pile the material to be dried obtained in step b into a fermented and dried sludge pile for fermentation and drying to obtain dried sludge;

Among them, the microbial agent is a composite bacterial agent, which is formed by mixing thermophilic bacillus, high-temperature actinomycetes, high-temperature-resistant yeast, and deodorant bacteria in a weight ratio of 6:6:5:3.

Further, the mass ratio of carbon and nitrogen in the mixture is 24-26:1.

Further, the carbon-to-nitrogen mass ratio is achieved in step a by adding auxiliary materials and stirring uniformly; the auxiliary materials are straw, straw or grass plants with high carbon content.

Furthermore, the moisture content of the dried sludge is 28%-32%.

Furthermore, the pile of fermented and dried mud is overturned once a day, and the fermentation and drying time is 10-12 days.

Further, the base material is dried sludge.

Still further, the stirring and mixing in the above step a is carried out in a closed negative pressure space; the closed negative pressure space is provided with a deodorization system; the deodorization system is used to treat the odor generated in the closed negative pressure space side by side.

Furthermore, the above steps b and c are carried out in a sludge biological drying tank; the sludge biological drying tank is set in an aerobic fermentation workshop; an aeration system is laid on the bottom of the tank, and a deodorization system is installed at the end of the tank. Air extraction device; the aeration system is used for intermittent forced ventilation of the biological drying tank, so that the aerobic fermentation bacteria in the compound bacterial agent can be better fermented.

The dried sludge treated by the sludge biological drying treatment method of the present invention is used to replenish land, or to make brick raw materials, or to generate energy for energy.

In the invention, the base material is added to adjust the water content of the sludge to be dried to 46%-54%, which is beneficial to the growth of bacteria and the fermentation and drying of the sludge.

The base material of the present invention adopts the dried sludge after drying treatment, and the materials are obtained locally, which reduces labor costs and costs caused by excavation and transportation, improves the utilization rate of equipment, and avoids Environmental pollution caused by digging loess and other base materials.

The invention adopts a reasonable ratio between the fresh sludge and the base material, which is beneficial to shorten the sludge drying time and improve the sludge treatment efficiency.

In the present invention, the carbon-to-nitrogen ratio in the sludge is adjusted by adding substances with high cellulose content, which is beneficial to the decomposition of organic matter by microorganisms, removal of harmful substances, and generation of heat energy to promote rapid drying of the sludge. The carbon-nitrogen ratio after theoretical analysis is equivalent to the required value (the carbon-nitrogen ratio is generally 25:1). The reason is that when microorganisms decompose organic matter, they need to assimilate about 1 part of nitrogen when assimilating 5 parts of carbon to form their own cell body, because the carbon-nitrogen ratio of microorganisms is about 5:1. When assimilating (absorbing and utilizing) 1 part of carbon, it needs to consume 4 parts of organic carbon to obtain energy, so when microorganisms absorb and utilize 1 part of nitrogen, they need to consume and utilize 25 parts of organic carbon. That is to say, the carbon-to-nitrogen ratio of microorganisms to the proper decomposition of organic matter is 25:1. When it is lower than its required value, further select auxiliary materials with higher cellulose content to supplement the carbon source. Therefore, the addition of auxiliary materials is beneficial to the composite bacterial agent to play a better role, and at the same time accelerate the drying of sludge.

Compared with the existing sludge drying process, the present invention also has the following advantages: Since the biological drying process of the present invention utilizes microbial aerobic fermentation to generate heat to evaporate water, the biological energy of the sludge itself is fully utilized, and ventilation and aeration are eliminated. In addition to the required power consumption, no external heating source is required, so it is an economical, energy-saving and environmentally friendly drying technology. By forced air blowing of the material to be dried. Improve the drying efficiency and shorten the drying cycle. Please refer to Table 1 below for a specific comparison.

Table 1. Comparison of thermal drying, natural drying and biological drying

Illustration

Fig. 1 is the variation curve diagram of the mixture drying temperature for the different formulations listed in Table 2;

Figure 2 is a graph showing the effect of bacteria on sludge drying.

experiment analysis

1. Base material and its ratio

Adding the base material is mainly used to adjust the moisture content of the fresh sludge (the sludge directly produced by the sewage treatment plant and after concentrated treatment). Generally speaking, the water content of fresh sludge produced from sewage treatment plants and concentrated treatment is 76% to 84% (about 80%). In order to facilitate the operation and ensure the growth of biological bacteria, by adding base to adjust its moisture content.

Raw materials: fresh sludge: use sewage treatment plant sludge with a water content of 80%.

Base material: use dried sludge (note: for the first time, a substitute with a comparable moisture content is used,

Such as loess, etc.), which is the product of sludge biological drying, with a moisture content of 30%.

The above two raw materials are prepared according to the requirements of Table 2 without adding biological agents. The mixture of each "item" is stirred evenly and then stacked into four drying tanks, and the temperature of the mixture in different periods is detected. change and compare.

Table 2. Ratio of fresh sludge and base material

It can be seen from Table 2 combined with Figure 1 that the temperature of formula A has the smallest change over time because of its high moisture content, and the temperature of formula D has the largest change. Formulas C and D are suitable as biological drying formulas, and formula D has the best effect. From the perspective of practical application, since the amount of base material used in formula D is twice that of fresh sludge, the volume after mixing doubles, which increases the burden on the biological drying tank and reduces the treatment rate of fresh sludge; from the temperature change and base Considering the two aspects of material usage, formula C is the most reasonable ratio, which is conducive to the drying of sludge.

Mix the same amount of sludge with different amounts of base material according to Table 2 above, put them into sludge drying tanks under the same conditions, and carry out natural drying to study the changes in the moisture content of different formulas in the same period of biological drying . See Table 3, the data listed in Table 3 is the moisture content of the mixed materials with different proportions of formulations sampled and measured on the 11th day of drying. It can be seen from Table 3 that formula C and formula D have the largest amount of water evaporation, formula C has a moisture content of 31% on the 11th day of drying, and formula D is 29%.

Table 3: Comparison of moisture content changes in biological drying of different formula materials

name Formula A Formula B Formula C Formula D Moisture content before biological drying 59.4% 55% 50% 46.7% Moisture content after 11 days of biological drying 45% 38% 31% 29% evaporated moisture 14.5% 17% 19% 17.7%

It can be seen from this: 1. It is feasible to mix fresh sludge with fresh sludge as a base material for biological drying after drying; 2. The optimal formula of fresh sludge and base material is a weight ratio of 1:1.4 to 1.6; 3. . Since biological drying is a process of biological activity, an appropriate carbon-to-nitrogen ratio is required. If the dried sludge is used as a base material for multiple cycles, it may lead to the loss of carbon sources. It should be considered to add it during each mixing process. Some auxiliary materials with high cellulose content are used to supplement carbon sources, and the amount of auxiliary materials added is between 5% and 8%.

2. Selection and ratio of bacterial agents

① Screening test of microbial agents.

Bacteria: a compound bacterial agent cultivated by a variety of strains provided by the pilot test base of agricultural biological preparations of China Agricultural University. The composite bacterial agent includes thermophilic bacillus, high temperature actinomycetes, high temperature resistant yeast, Bacteria four kinds of bacteria. Among them, the minimum growth temperature of thermophilic Bacillus is 28°C, the maximum growth temperature is 70-77°C, and the optimum growth and reproduction temperature is 56-65°C. The suitable temperature for the growth of hyperthermic actinomycetes is 57°C to 60°C; the suitable temperature for sporulation is 55°C and 37°C. The most suitable growth temperature for thermostable yeasts is generally between 20°C and 40°C, and they multiply in large numbers in the initial stage of biological drying, which plays a role in heating up and adjusting the pH value. The deodorant bacteria is compounded by two strains of aerobic deodorant bacteria. The above four kinds of bacteria were used to prepare the composite bacterial agents in different proportions, namely bacterial agents I, bacterial agents II, bacterial agents III and bacterial agents IV. See Table 4 for the specific proportions.

Table 4: Proportioning (weight ratio) of composite bacterial agents

Sludge: fresh sludge after concentrated treatment in domestic sewage treatment plants, with a water content of about 80%.

Test method: After stirring and mixing fresh sludge and base material at a weight ratio of 1:1.5, four piles of the same size, shape, and weight were built, each pile was 10 tons. Then the four kinds of biological bacteria agents are evenly stirred into the corresponding four heaps at a ratio of 2‰ (weight ratio, based on the total amount of fresh sludge and base material). Observe the temperature change every day, and at the same time detect the change of the moisture content of the pile, and draw the change curve, as shown in Figure 2.

It can be seen from Figure 2 that for the four piles treated with different bacterial agents, the temperature was measured for 11 consecutive days. When the temperature of the pile rises to 52°C, it hardly increases. Comparing treatment 3 and treatment 4, treatment 4 is the best, the temperature rises the fastest at the same time, and can quickly evaporate the water in the pile, and it is the best biological agent for biological drying.

In the above experiment, after 11 days of biological drying, the materials of each pile were taken for moisture detection respectively.

Table 5: Comparison of different bacterial agents on the water evaporation of the heap

name Bacteria I Bacteria II Bacteria III Bacteria IV Moisture content before biological drying 50% 50% 50% 50% Moisture content after 11 days of bio-drying 37% 34% 31% 29% evaporated moisture 13% 16% 19% twenty one%

It can be seen from Table 5 that bacterial agent IV has the highest evaporation water content, and the water content of 50% can be reduced to 29% within 11 days of biological drying, and the dehydration rate has reached about 40%, and the dehydration effect is relatively obvious. Therefore, the microbial agent of the present invention adopts a composite microbial agent mixed by thermophilic bacillus, high-temperature actinomycetes, high-temperature-resistant yeast, and deodorant bacteria, and the weight ratio between them is as follows: thermophilic bacillus: high-temperature actinomycetes Nematodes: high temperature resistant yeasts: deodorizing bacteria is 6:6:5:3.

②. Contrast test of the addition amount of bacterial agent Ⅳ

In the actual production process, the amount of bacterial agent used is related to the cost of disposal. In order to study the effect of the amount of bacterial agent used on the evaporation of sludge drying water, we evaporated the above-mentioned selected bacterial agent IV in different amounts. In the test of moisture effect, the drying cycle was 11 days, and the results are shown in Table 6.

It can be seen from Table 6 that when the amount of bacterial agent used is above 2‰, there is no significant difference in water evaporation. Under the premise of considering the treatment cost, the reasonable usage amount of bacterial agent IV is the best between 2‰～2.5‰ (weight ratio).

Table 6: Comparison of different dosages of bacterial agent Ⅳ on water evaporation

Dosage (weight ratio) Moisture content before drying Moisture content after drying Evaporation 1.5‰ 50% 32% 18% 2‰ 50% 29% twenty one% 2.5‰ 50% 28% twenty two% 3‰ 50% 28% twenty two%

It can be seen from the above experiments that (1) sludge biological drying technology uses the bioenergy produced by the degradation of organic matter in the high-temperature aerobic fermentation process of microorganisms, and cooperates with forced ventilation to promote the evaporation and removal of water, so as to achieve rapid sludge drying. The bacterial agent IV screened in the test is a composite microbial agent cultivated by four strains of concentrated thermophilic bacteria and thermophilic bacteria. (2) When the amount of bacterial agent used is above 2‰, there is no significant difference in water evaporation. Under the premise of considering the treatment cost, the reasonable usage amount of bacterial agent IV is the best between 2‰～2.5‰ (weight ratio). (3) Since sludge biological drying uses the biological energy produced by the degradation of organic matter in the high-temperature aerobic fermentation process of microorganisms to achieve the purpose of evaporating water, it is necessary to timely ventilate and supplement oxygen during the entire drying process according to the temperature changes in the pile. Keep the activity of biological bacteria at a high level.

Detailed ways

Embodiment one

The sludge biological drying treatment method of the present invention is a drying treatment process of fresh sludge with a water content of 76% to 84% after concentration treatment. In this embodiment, 3000 kg of concentrated fresh sludge is taken directly from the domestic sewage treatment plant, and its water content is 80% after testing. For the indicators of the fresh sludge, please refer to Table 7; in addition, it also contains a large amount of organic matter, coliform bacteria, insect eggs, etc.

Table 7: Contents of main harmful substances in fresh sludge.

name Mercury (Hg) Arsenic (As) Lead (Pb) Cadmium (Cd) Chromium (Cr) content 0.322 10.26 60.2 1.23 82.6

The biological drying treatment method of sludge of the present invention comprises the following steps:

a, deploy fresh sludge water content: the above-mentioned fresh sludge with a water content of 80% and the base material with a water content of 30% are stirred and mixed in a weight ratio of 1:1.5 to obtain a mixture with a water content of 50%. Select the base material 4500kg that moisture content is 30% for use simultaneously. The base material is preferably dried sludge after sludge drying treatment. When using for the first time, materials with equivalent water content (such as loess or ash) can be selected to replace the dried sludge after sludge drying treatment. In this embodiment, the mixed base material of loess and ash is selected as the base material instead of dried sludge. The mixed base material weighs 4500 kg and has a moisture content of 30%. According to theoretical analysis, the moisture content of fresh sludge and base material after mixing is 50%. At the same time, the carbon-nitrogen mass ratio in the mixture is detected, and the carbon-nitrogen mass ratio is controlled between 24 and 26:1. In this range of carbon-nitrogen mass ratio, it is beneficial for microorganisms to decompose organic matter. If the carbon-nitrogen ratio is too large, microorganisms will The decomposition of the product slows down, which is not conducive to drying. It has been detected that the mass ratio of carbon to nitrogen is about 25:1, which meets the above conditions.

3000kg of fresh sludge with a water content of 80% and 4500 kg of base material with a water content of 30% are stirred and mixed to obtain a mixture of 7500 kg; the water content of the mixture is 50%; the mass ratio of carbon and nitrogen in its substance content is 25:1.

The stirring and mixing of the fresh sludge and the base material is carried out by the mixer in the closed negative pressure space (the closed negative pressure space is generally designed according to the size and specification of the mixer). In this embodiment, the fresh sludge and the base material are quantitatively transported to the mixing station in the closed negative pressure space by the screw conveyor respectively; The odor generated in the space is treated and discharged after reaching the standard. The odor generated in the closed negative pressure space is treated by the deodorization system and then discharged up to standard. The mixer in the mixing station fully mixes the fresh sludge and the base material to complete the mixing process. The mixing time of the mixer depends on the capacity and speed of the mixer. Generally, for a mixer with a speed of 100 rpm, the mixing time can be 60-90s. The above-mentioned fresh sludge and base material are uniformly stirred by a mixer to obtain a mixture.

b. Add bacterial agent: add 2.0‰～2.5‰ of compound bacterial agent to the mixed material obtained in step a and mix well to obtain dry chemical material. The above-mentioned mixture is transported to the sludge biological drying tank through the distributor. The sludge biological drying tank (or drying tank) can adopt the following specifications: length x width x height is 72m x 4.28m x 2.4m, and its daily sludge treatment volume is 200t/d. The sludge biological drying tank is set in the aerobic fermentation workshop. The bottom of the tank is equipped with an aeration system, the head of the tank is equipped with a compost turning machine and a track-changing trolley channel (for the compost turning machine to transfer to the tank), and the tail of the tank is equipped with a deodorizing ventilation device. Prepare the relevant equipment according to the number of chemical tanks. If 10 biological drying tanks are set up, it can be matched with 2 compost turning machines, 2 track changing trolleys, 4 aeration fans and 10 deodorizing fans. Add 15kg of composite bacterial agent at a ratio of 2.0‰ (based on the total amount of the mixture) to the mixture that is transported to the sludge biological drying tank by the distributor, and the composite bacterial agent is evenly sprayed to the mixture. The surface is then turned by a compost turner so that the compound bacterial agent can be evenly mixed into the mixture. Through the above process, about 7500kg of chemical material to be dried is obtained.

c. Fermentation and drying of sludge: Pile the material to be dried obtained in step b into a fermented and dried sludge pile for fermentation and drying to obtain dried sludge. The above-mentioned materials to be dried are then piled up into mud piles by a stacker in the sludge biological drying tank for fermentation and drying. The height of the pile of fermented and dried sludge is not more than 2m, and the width is not more than 4m. Then the pile of mud is turned over once a day by the stacker and piled up into piles, and the moving distance of each turning is not less than 6m. The turning process is the process of moving the piled mixture. The aeration system is used for intermittent forced ventilation of the sludge in the biological drying tank during the sludge fermentation and drying process, so that the aerobic fermentation bacteria in the compound bacterial agent can be better fermented. The above-mentioned fermented and dried mud heap piled up is fermented and dried, and the aeration system is carried out with an interval of 3 hours and forced ventilation of ventilation for 1 hour (the general ventilation time and interval are related to the height of the mud heap, and when the height of the heap is 2m In some cases, an interval of 3 hours and ventilation for 1 hour) can be used to allow better fermentation of the aerobic fermentation strains. The aeration system includes a fan, pipelines, valves and a control system, and the pipelines are laid on the tank bottom and the tank wall. After 11 days of fermentation and drying, the moisture content of the material to be fermented and dried was reduced to 30%, and about 5340 kg of dry sludge was obtained. This dried sludge achieves sludge reduction. The dried sludge is automatically transported to the finished product warehouse through the belt conveyor system for other uses, such as recycling. The obtained dry sludge has reached relevant quality standards after testing. Please refer to Table 8 for specific data.

Table 8: Test results of dried sludge.

Test items Quality Index Test results Mass fraction of organic matter (based on drying basis), % ≥45 58.9 Nitrogen (N) mass fraction (based on oven dry basis), % / 2.46 Phosphorus (P2O5) mass fraction (calculated on an oven dry basis), % / 2.29 Potassium (K2O) mass fraction (calculated on an oven-dried basis), % / 2.64 The mass fraction of total nutrients (based on drying basis), % ≥5 7.39 Moisture mass fraction,% ≤30% 21.2 acidity, pH 5.5～8.5 7.8 Total arsenic (As) (calculated on a dry basis), mg/kg ≤15 4.6 Total mercury (Hg) (calculated on a dry basis), mg/kg ≤2 0.074 Total cadmium (Cd) (calculated on a dry basis), mg/kg ≤3 0.082 Total lead (Pb) (calculated on a dry basis), mg/kg ≤50 26.7 Total chromium (Cr) (calculated on a dry basis), mg/kg ≤150 25.3 Ascaris egg mortality, % ≥95 97 Number of fecal coliform bacteria, pc/g ≤100 75

The dried sludge obtained above contains various organic substances, various nutrients and energy. It can be widely used in the following aspects: first, land utilization, to supplement the organic matter and nutrients in the sludge to the land; second, to recover the energy in the sludge through anaerobic digestion or incineration; third, through the use of dried sludge The incinerated ash is used to make bricks to realize sludge recycling.

Embodiment two

The sludge biological drying treatment method of the present invention is a drying treatment process of fresh sludge with a water content of 76% to 84% after concentration treatment. In this embodiment, 5000 kg of concentrated fresh sludge is taken directly from the domestic sewage treatment plant, and its water content is 82% after testing. The indicators of the fresh sludge are roughly the same as in Table 7 above. The biological drying treatment method of sludge of the present invention comprises the following steps:

a, allotment fresh sludge water content: 3000kg of the above-mentioned fresh sludge with a water content of 82% and the base material with a water content of 30% are stirred and mixed in a weight ratio of 1: 1.6 to obtain a mixture with a water content of 50%. The base material used in this example is the dried sludge in Example 1, with a moisture content of 30% and a weight of 4800kg. According to theoretical analysis, the moisture content of fresh sludge and base material after mixing is 50%. . At the same time, the carbon-to-nitrogen ratio in the mixture was detected, and the carbon-to-nitrogen mass ratio was detected to be 22:1, which is not conducive to microbial decomposition of organic matter. After adding auxiliary materials to the mixture, its carbon-nitrogen ratio meets the standard. The auxiliary material added in the present embodiment is the mixture of straw and forage. According to the principle of local materials, straw can also be used. The particle size of the added auxiliary materials is not greater than 3mm, and the moisture content is between 10% and 25%. The amount of auxiliary materials added can be determined according to the weight of the mixture, the measured carbon-nitrogen mass ratio and the properties of auxiliary materials.

3000kg of fresh sludge with a moisture content of 82% and 4800kg of dry sludge with a moisture content of 30% are stirred, and a certain amount of straw and forage auxiliary materials are added to mix and mix to obtain a mixture of about 7800kg; The water content is 50%; the mass ratio of carbon and nitrogen in the material content is 24-26:1.

The stirring and mixing of the fresh sludge and the base material is carried out by a mixer in a closed negative pressure space. The closed negative pressure space is equipped with a deodorization system, and the odor generated in the closed negative pressure space is treated by the deodorization system and then discharged up to standard. The above-mentioned fresh sludge, dry sludge and auxiliary materials are uniformly stirred by a mixer to obtain about 7800 kg of mixed materials.

B, add bacterial agent: add the compound bacterial agent of 2.5‰ of the weight of mixture to the compound material obtained in step a and mix well, get the material to be dried. Add 19.5kg of compound bacteria agent to the mixture transported by the distribution machine to the sludge biological drying tank at a ratio of 2.5‰ (in terms of the total amount of the mixture), and the compound bacteria agent is evenly sprayed onto the mixture surface, and then turned by the turner so that the compound bacterial agent can be evenly mixed into the mixture. Through the above process, about 7800kg of chemical material to be dried is obtained.

c. Fermentation and drying of sludge: Pile the material to be dried obtained in step b into a fermented and dried sludge pile for fermentation and drying to obtain dried sludge. The above-mentioned materials to be dried are then piled up into mud piles by a stacker in the sludge biological drying tank for fermentation and drying. The mud heap is turned and thrown once a day by a stacker and piled into piles. The above-mentioned fermented and dried mud heap piled up is fermented and dried, and the aeration system is forced to ventilate for 3 hours at an interval of 1 hour so that the aerobic fermentation bacteria can be better fermented. The aeration system includes a fan, pipelines, valves and a control system, and the pipelines are laid on the tank bottom and the tank wall. After 12 days of fermentation and drying, the water content of the material to be fermented and dried was reduced to 28%, and about 5400 kg of dry sludge was obtained. This dried sludge achieves sludge reduction. The dried sludge is automatically transported to the finished product warehouse through the belt conveyor system for other uses, such as recycling. The obtained dry sludge has reached relevant quality standards after testing. The specific data is close to the data in Table 8.

The dry sludge obtained above contains various organic substances, various nutrients and energy. It can be widely used in the following aspects: first, land utilization, to supplement the organic matter and nutrients in the sludge to the land; second, to recover the energy in the sludge through anaerobic digestion or incineration; third, through the use of dried sludge The incinerated ash is used to make bricks to realize sludge recycling.

Claims (9)

1. The sludge biological drying treatment method is to dry the fresh sludge with a moisture content of 76% to 84% after concentration treatment, and it is characterized in that: it includes the following steps: a, deployment of fresh sludge water content: the fresh sludge and the base material with a water content of 28% to 32% are stirred and mixed in a weight ratio of 1:1.4 to 1.6 to obtain a mixture; b. Add bacterial agent: add 2.0‰～2.5‰ of the bacterial agent of the weight of the mixed material to the mixture obtained in step a and mix well to obtain the dry material; c. Fermentation and drying of sludge: pile the material to be dried obtained in step b into a fermented and dried sludge pile for fermentation and drying to obtain dried sludge; Wherein, the bacterial agent is a composite bacterial agent, which is formed by mixing thermophilic bacillus, thermophilic actinomycetes, thermostable yeast, and deodorant bacteria in a weight ratio of 6:6:5:3. 2. The sludge biological drying treatment method according to claim 1, characterized in that: the mass ratio of carbon and nitrogen in the mixture is 24-26:1. 3. The sludge biological drying treatment method according to claim 2, characterized in that: the carbon-to-nitrogen mass ratio is achieved in step a by adding auxiliary materials and stirring evenly; the auxiliary materials are high in carbon content stalks, straw or grass plants. 4. The sludge biological drying treatment method according to claim 3, characterized in that: the moisture content of the dried sludge is 28%-32%. 5. The sludge biological drying treatment method according to claim 4, characterized in that: the fermented and dried sludge pile is overturned once a day, and the fermentation and drying time is 10-12 days. 6. The sludge biological drying treatment method according to claim 5, characterized in that: the base material is dried sludge. 7. The sludge biological drying treatment method according to claim 1 or 2 or 3 or 4 or 5 or 6, characterized in that: it is characterized in that: the stirring and mixing in step a is carried out in a closed negative pressure space ; The closed negative pressure space is equipped with a deodorization system; the deodorization system is used to process and discharge the odor generated in the closed negative pressure space. 8. The sludge biological drying treatment method according to claim 7, characterized in that: said steps b and c are carried out in a sludge biological drying tank; the sludge biological drying tank is arranged in an aerobic fermentation tank In the workshop; the bottom of the tank is equipped with an aeration system, and the end of the tank is equipped with a deodorizing ventilation device; the aeration system is used for intermittent forced ventilation of the biological drying tank, so that the aerobic fermentation bacteria in the compound bacterial agent Seeds get better fermentation. 9. A dried sludge treated by the sludge biological drying treatment method according to any one of claims 1 to 8, characterized in that: the dried sludge is used to replenish land or to make bricks raw materials, or sources of energy for energy production.