CN103539494A - Bin type sludge aerobic composting method - Google Patents

Abstract

The invention discloses a bin-type sludge aerobic composting method. Build a bin-type sludge aerobic composting device, including fermentation bins, ventilation devices and real-time online monitoring equipment; evenly lay PVC spherical suspension filter materials with a diameter of 50mm in the fermentation bins, and then dewater sludge from sewage treatment plants and Sawdust is mixed evenly according to the mass ratio of sludge: sawdust = 2:1-5:1, and put into the fermentation bin; before stacking, control the moisture content and volatile organic compounds of the mixed pile, that is, VS, at 60%-70% and 65% respectively. %-80%; insert the temperature probe rod and oxygen probe rod into the pile body, wherein the temperature at the center point of the pile body is used as the control temperature value, and the segmented oxygen-temperature feedback ventilation control strategy invented by the application number 201310076268.9 is adopted. The composting process takes 14-18 days in total. The invention has the functions of temperature control, air supply, exhaust, unloading and on-line monitoring. While realizing the integrated operation of the whole composting process, it can meet the technical requirements of rapid decomposition, high-efficiency dehydration and harmlessness of the compost.

Description

A kind of warehouse type sludge aerobic composting method

technical field

The invention relates to a composting technology for stabilizing and harmless organic solid waste, in particular to a bin-type sludge aerobic composting method.

Background technique

With the acceleration of urbanization, the amount of urban sewage treatment has increased year by year, and the sludge production in sewage has also risen sharply. The composition of municipal sludge is complex. In addition to high moisture content and perishability, it also contains pathogenic bacteria, parasite eggs and toxic substances, and is accompanied by stench. If it enters the environment without proper treatment, it will directly pose a threat to the atmosphere, water bodies and human health. Municipal sludge is rich in organic matter and nutrients needed for plant growth and reproduction such as nitrogen, phosphorus, and potassium. Composted urban sludge can be used to produce organic fertilizers, or to improve soil, increase sealing fertility, and effectively realize sewage Mud stabilization, harmlessness, resource utilization.

Aerobic composting is a process in which aerobic microorganisms in sludge are used to biodegrade organic matter under the condition of effectively controlling moisture and oxygen. Compared with anaerobic composting, it has the characteristics of short composting cycle, high degradation rate of organic matter, and easy manipulation.

At present, the aerobic composting technology being researched and developed at home and abroad is mainly strip stacking and forced ventilation static stacking process. The former has the disadvantages of large area, low treatment efficiency, and difficult to control odor, while the latter is the mainstream fermentation process, but the sludge treatment scale of this technology is relatively large, so it has high requirements for the site and supporting equipment, so it is not suitable Decentralized and small-scale sludge generation. The aerobic composting fermentation bin can be divided into vertical type, cylinder type and horizontal type according to its shape. Patent No. 201220121636.8 reports a vertical fermentation bin. Patent No. 02208727.7 reports on the drum type sludge composting fermentation equipment. Among them, the vertical fermentation bin has a large processing capacity and occupies a small area, but it is easy to cause uneven mixing of materials, resulting in unsatisfactory partial fermentation results; the drum type fermentation bin has the advantages of small footprint, flexible operation, and low energy consumption, but its fermentation bin The cross-sectional area of the bottom is large, and the buffer layer lacks the homogenization of the ventilation air flow, which makes the material compacted and even local anaerobic.

Contents of the invention

The purpose of the present invention is to provide an intelligent bin-type aerobic composting method, which has the functions of temperature control, air supply, exhaust, unloading and online monitoring, and realizes the integrated operation of the whole composting process while achieving rapid maturity of the compost , high-efficiency dehydration and harmless process requirements.

The specific steps are:

(1) Build a bin-type sludge aerobic composting device, including a fermentation bin, ventilation device and real-time online monitoring equipment; the fermentation bin is installed on a stainless steel bracket, and a 0.5t-1.0t electric hoist is set on the stainless steel bracket to realize automatic unloading. The top of the fermentation bin is equipped with a temperature probe, an oxygen probe and an exhaust pipe. The body of the fermentation bin is a PVC (polyvinyl chloride) double-layer cylinder, and a hot air insulation layer is formed between the inner wall layer and the outer wall layer; the fermentation bin The side wall is provided with an exhaust pipe; the bottom of the fermentation chamber is provided with a buffer layer, a deflector flap, an air intake hole, and a drain pipe; the deflector flap is jagged with an inclination angle of 90 degrees; the deflector flap is provided with a hole cover The ventilation system includes an air pump, a flow meter, a solenoid valve and an air duct, the flow meter and the electromagnetic valve are located near the air pump, and the air pump is connected to the air intake through the air duct; the real-time online monitoring equipment includes an oxygen monitor, a temperature monitor , Carbon dioxide monitoring lines, ammonia monitoring lines and hydrogen sulfide monitoring lines.

(2) When the outdoor temperature is 15°C-30°C, firstly, evenly lay PVC spherical suspension filter material with a diameter of 50mm on the perforated cover plate in the fermentation chamber, and then dewater the sludge and sawdust from the sewage treatment plant according to the Dewatered sludge: sawdust = 2:1-5:1 mass ratio, mix evenly, put into the fermentation bin; control the moisture content and VS (volatile organic compounds) of the mixed pile before stacking at 60%-70% and 65% respectively Between %-80%.

(3) Insert the temperature probe rod and oxygen probe rod into the pile body, and take the temperature of the center point of the pile body as the control temperature value, and adopt the segmented oxygen-temperature feedback ventilation control strategy invented by the application number 201310076268.9, that is, during the adaptation period Control the heap without ventilation; during the rapid heating period, adjust the ventilation rate according to the oxygen consumption rate of the heap to ensure sufficient oxygen supply to the heap; During the dehydration period, a higher fixed ventilation rate is adopted to achieve the purpose of dehydration and cooling of the pile. When the air pump is started, the air enters the air chamber through the air pipe, and passes through the buffer layer, deflector flap, perforated cover plate and spherical suspension filter material in sequence to make the air distribution fully uniform; The gaseous insulation layer reduces the heat loss from the pile to the device environment and keeps the pile warm. The composting process lasted 14-18 days in total, of which the time for the temperature of the compost to rise to 55°C was 3-4 days, the high temperature period above 50°C was maintained for 6-8 days, and the temperature of the compost was maintained for 4-6 days above 55°C. From the 10th day began to decline rapidly.

The present invention has remarkable beneficial effect:

1. The present invention is equipped with a real-time online temperature, oxygen, and exhaust gas monitoring device, which can store the real-time data detected by the probe through the data acquisition system in real time, which solves the problem that current hand-held instruments are difficult to obtain continuous data.

2. The bottom of the fermentation bin of the present invention is provided with a buffer layer, a deflector flap, a perforated cover plate, and a spherical suspension filter material from bottom to top, and the air is introduced by the air pump through the air duct and is effectively homogenized in the blast chamber. It avoids the low composting efficiency caused by the unsatisfactory heating effect of the heap due to excessive local ventilation and the uneven ventilation.

3. The present invention relies on hot air flow to shape the insulation layer before the two layers of side walls inside and outside the fermentation chamber, uses the heat emitted by the pile itself to conduct heat transfer to the air, and reacts to the pile for heat preservation. Compared with the external water bath heating method, the energy consumption is lower.

4. The present invention is equipped with a 0.5t-1.0t miniature electric hoist, which can realize automatic unloading and reduce labor.

Description of drawings

Fig. 1 is a schematic structural diagram of a bin-type sludge aerobic composting device of the present invention.

Marks in the figure: 1-temperature probe; 2-oxygen probe; 3-exhaust pipe; 4-outer wall layer; 5-inner wall layer; 6-insulation layer; 7-exhaust pipe; 8-buffer layer; 9-guide Flow baffle; 10-air inlet; 11-drain pipe; 12-porous cover plate; 13-spherical suspension filter material; 14-flow meter; 15-solenoid valve; 16-air pump; 17-exhaust gas monitor; 18-oxygen monitor; 19-temperature monitor; 20-electric hoist; 21-stainless steel bracket; 22-carbon dioxide monitoring circuit; 23-ammonia monitoring circuit; 24-hydrogen sulfide monitoring circuit.

Fig. 2 is a graph of temperature dynamic changes in an embodiment of the present invention.

Fig. 3 is a monitoring diagram of oxygen dynamic changes in an embodiment of the present invention.

Fig. 4 is a monitoring diagram of carbon dioxide dynamic change according to the embodiment of the present invention.

Fig. 5 is a monitoring diagram of the dynamic change of ammonia gas according to the embodiment of the present invention.

Fig. 6 is a monitoring diagram of the dynamic change of hydrogen sulfide according to the embodiment of the present invention.

Detailed ways

Example:

(1) The bin-type sludge aerobic composting device is shown in Figure 1, including fermentation bins, ventilation devices and real-time online monitoring equipment; the dimensions of the fermentation bin are Ǿ×H=800mm×1300mm, and the effective volume is Ǿ×H=600mm×1100mm , the fermentation bin is installed on a stainless steel bracket 21, and a 0.5t-1.0t electric hoist 20 is set on the stainless steel bracket 21; a temperature probe 1, an oxygen probe 2 and an exhaust pipe 3 are arranged on the top of the fermentation bin, and the fermentation bin body is PVC double Layer cylinder, the hot air flow insulation layer 6 is formed between the inner wall layer 5 and the outer wall layer 4; the side wall of the fermentation bin is provided with an exhaust pipe 7; And drainage pipe 11; buffer layer 8 thickness is 25cm, deflector flap 9 is serrated, inclination is 90 degrees; diversion flap 9 is provided with hole cover plate 12; ventilation system includes air pump 16, flow meter 14, electromagnetic Valve 15 and air pipe, flow meter 14 and solenoid valve 15 are located at air pipe near the air pump, and air pump 16 is connected with air inlet 10 through air pipe.

Temperature probe 1 has a measuring range of -10°C-100°C and a length of 1500mm. From the outlet end to the bottom, the length of 1200mm is temperature 1, the length of 900mm is temperature 2, the length of 700mm is temperature 3, and the length of 450mm is temperature 4 ;The range of oxygen probe 2 is 0-25%, the length is 1000mm, and the probe is set at the bottom; the temperature probe 1 and oxygen probe 2 are completely sealed, the surface is galvanized and anti-corrosion, and the interior is heat-insulated.

Exhaust gas monitor 17 is equipped with backlight LCD, which can display gas concentration value, CO ₂ range is 0-20%, H ₂ S, NH ₃ maximum ranges are 500, 1000ppm (parts per million) respectively; flowmeter 14 is a thermal type Gas mass flow meter with a range of 0-25slpm (standard liters per minute).

(2) The minimum outdoor temperature is 18°C and the maximum temperature is 25°C. Firstly, the spherical suspension filter material 13 with a diameter of 50 mm is evenly laid on the perforated cover plate 12 in the fermentation bin, and then the dewatered sludge from the sewage treatment plant is mixed evenly according to the mass ratio of sludge: sawdust = 4:1, and the into the fermentation chamber. The moisture content and VS (volatile organic compounds) of the unmixed pile before stacking were 65% and 78%, respectively.

(3) Insert the temperature probe 1 and the oxygen probe 2 into the pile body, and take the temperature of the center point of the pile body as the control temperature value, and adopt the control strategy of segmented oxygen-temperature feedback ventilation, that is, during the adaptation period (within 1 day of stacking) and the temperature is less than 28°C) to keep the pile without ventilation; during the rapid heating period (temperature reaches 28°C), when the oxygen content in the pile is lower than 15%, adjust the ventilation flow to 8L/min (litres/minute), higher than When the temperature is 15%, adjust the ventilation flow rate to 6 L/min; in the high temperature continuous period (the temperature at the center point of the pile body reaches 50°C), when the temperature at the center point of the pile body is between 50°C and 55°C, adjust the ventilation flow rate to 4 L/min, when it is between 55°C and 60°C, adjust the ventilation flow to 6 L/min, and when it is greater than 60°C, adjust the ventilation flow to 10 L/min; during the material dehydration period (after 8 days of high temperature duration) After that), a high ventilation flow rate of 10 L/min has been used to dehydrate and cool the pile quickly for 3 days. After the air pump 16 is started, the air enters the air chamber through the air pipe, and passes through the buffer layer 8, the deflector flap 9, the perforated cover plate 12 and the spherical suspension filter material 13 in turn, so that the air distribution is fully uniform. During the composting process, relying on the high-temperature tail gas of the compost to form a gaseous insulation layer to reduce the heat loss from the compost to the environment of the device and keep the compost insulated. The composting lasted 16 days, of which the temperature of the compost body rose to 55°C for 4 days, the high temperature period above 50°C was maintained for 8 days, and the temperature of the compost body dropped rapidly from the 10th day. The body temperature meets the requirements of the "Hygienic Standard for Harmless Feces (GB7959-87)".

At the end of composting, the moisture content and VS of the compost were measured to be 52% and 67%, respectively, realizing the reduction of compost and the degradation of organic matter; the measured GI (germination index) value was greater than 80%, indicating the toxicity of the compost has basically disappeared.

Claims (1)

1. a storehouse formula sludge aerobic compost method, is characterized in that concrete steps are:

(1) set up a storehouse formula mud aerobic composting device, comprise fermentation cabin, ventilation plant and real time on-line monitoring equipment; Fermentation cabin is arranged on stainless steel stent, and 0.5t-1.0t electric hoist is set on stainless steel stent, to realize, automatically unloads heap; Fermentation cabin top is provided with temperature feeler lever, oxygen feeler lever and vapor pipe, and fermentation cabin body is that polyvinyl chloride is PVC double-layer circular cylinder, forms hot gas flow thermal insulation layer between its inner wall layer and outer wall layer; Fermentation cabin sidewall is provided with offgas duct; Fermentation cabin bottom is provided with buffer layer, water conservancy diversion flap, air inlet port, water shoot; Water conservancy diversion flap indentation, inclination angle is 90 degree; Water conservancy diversion flap is provided with blind patch; Ventilation system comprises air pump, under meter, magnetic valve and airduct, and under meter and magnetic valve are located at airduct near air pump place, and air pump is connected with air inlet port by airduct; Real time on-line monitoring equipment comprises oxygen monito, temperature monitor, carbon dioxide monitoring circuit, ammonia Monitoring Line and hydrogen sulfide Monitoring Line;

(2) when temperature is 15 ℃-30 ℃ out of doors, first, in fermentation cabin, having the polyvinyl chloride that on blind patch, evenly laying diameter is 50mm is PVC ball-type suspended filter material, then the dewatered sludge of sewage work and sawdust are mixed according to the mass ratio of dewatered sludge: sawdust=2:1-5:1, pack in fermentation cabin; Before upper heap, control hybrid reactor body water ratio and volatile organic matter are that VS is respectively between 60%-70% and 65%-80%;

(3) temperature feeler lever, oxygen feeler lever are inserted to heap body, wherein using heap body central point temperature as controlling temperature value, adopt the control strategy of the segmentation oxygen-feedback ventilation temperature of the invention that application number is 201310076268.9, in the adaptive phase, control heap body stuffy; The phase that is rapidly heated regulates ventilation according to heap body oxygen consumption rate, guarantees that the oxygen supply of heap body is abundant; The high temperature extended period is adjusted ventilation according to heap body central point temperature, makes to pile the continuous high temperature that body maintains certain hour; The material dewatering phase is taked higher fixedly ventilation, makes to pile the object that body reaches dehydration cooling; After air pump starts, air enters air compartment by airduct, successively by buffer layer, water conservancy diversion flap, have blind patch and ball-type suspended filter material, make gas distribution full and uniform; In composting process, rely on heap body high-temperature tail gas to form gaseous state thermal insulation layer, reduce heap body to the calorific loss of device context, heap body is incubated; Compost process is lasted 14-18 days altogether, and wherein to rise to the time of 55 ℃ be 3-4 days to heap temperature, and 50 ℃ of above pliotherm periods maintain 6-8 days, and 55 ℃ maintain 4-6 days above, and the temperature of heap body is decline rapidly since the 10th day.

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