A system for treating condensate waste liquid produced by municipal sludge compost fermentation

Abstract

The utility model provides a kind of municipal sludge compost fermentation produced condensate waste liquid processing system, it is related to condensate waste liquid processing field, including mixed sedimentation tank, ozone reaction device, dilution tank, and mixed sedimentation tank is equipped with dosing opening, sewage inlet, condensate waste liquid enters into mixed sedimentation tank from sewage inlet, and reagent is added to mixed sedimentation tank by dosing opening, and the reagent is added is calcium hydroxide solution, and the sewage outlet of mixed sedimentation tank is connected by pipeline and the water inlet of ozone reaction device, and the water outlet of ozone reaction device is connected by pipeline and the water inlet of dilution tank;After reaction and deposition, sludge is entered into the feed end of sludge compost system by sludge outlet;Sewage and tail water addition ratio in dilution tank are 1:10+;Beneficial effect: the liquid after processing of the application is used as supplementary nitrogen fertilizer and garden greening water is mixed and irrigated, and the generated precipitate is used for compost fermentation to enhance sludge fertility, and the application achieves the purpose of source treatment and the treatment process is simple.

Description

Technical Field

[0001] This utility model relates to the field of condensate wastewater treatment, and in particular provides a condensate wastewater treatment system for municipal sludge composting and fermentation. Background Technology

[0002] Sludge composting often employs high-temperature aerobic fermentation technology, which involves naturally fermenting municipal sludge with a moisture content of 80% in an aerobic environment. The fermentation temperature can reach 70-80 degrees Celsius, and the fermentation products are made into garden organic fertilizer.

[0003] Due to the high temperature during fermentation and the presence of air, the entire production process generates a large amount of steam. This steam, carrying odorous gases, is drawn by a deodorizing fan to a biological filter for deodorization. After condensation, the hot steam produces a large amount of condensate wastewater that accumulates in the filter. Testing revealed that this wastewater has a CODcr concentration exceeding 1000 mg / L, a BOD5 concentration around 100 mg / L, an ammonia nitrogen concentration exceeding 1000 mg / L, and a total nitrogen concentration exceeding 2000 mg / L. It is classified as high-ammonia-nitrogen wastewater with a B / C ratio below 0.3, indicating poor biodegradability. Based on these test data, this wastewater cannot be directly discharged into the industrial park's wastewater treatment plant and requires on-site pretreatment.

[0004] When the sludge composting plant is not operating at full capacity, the daily output of condensate wastewater is about 10 tons. Most of the condensate wastewater is sprayed back into the mesophilic fermentation zone to enhance the fermentation activity of microorganisms. As the production load increases, the output of condensate wastewater also increases. Under full-load operation, the daily output of condensate wastewater approaches 200 tons, with a large amount of water produced, which cannot be disposed of by the spraying method. Therefore, it is imperative to explore a process technology route that is cost-effective, quick to produce results, easy to operate, and practical.

[0005] Currently, various condensate treatment systems for municipal sludge composting and fermentation have been developed on the market. For example, patent number 202321332544.9 discloses a treatment system for condensate from sludge hydrolysis and evaporation. This system uses a pretreatment device to adjust the wastewater quality and quantity; a hydrolysis acidification device to improve the biodegradability of the pretreated wastewater and remove some COD; a biochemical treatment device to remove COD and ammonia nitrogen from the hydrolyzed and acidified wastewater; and an ultrafiltration device to retain COD in the biochemically treated wastewater and discharge compliant wastewater. The ultrafiltration device further retains COD in the evaporation condensate, ensuring the treated evaporation condensate meets discharge standards. Sludge drying condensate treatment systems are also available on the market. For example, patent number 201510908293.8 discloses a sludge drying condensate treatment method that uses an equalization tank, anaerobic reactor, biological selector, sequencing batch reactor (SBR), and high-concentration ozone reactor to achieve condensate treatment.

[0006] However, most condensate wastewater treatment systems on the market currently use conventional wastewater treatment methods, which are complex and require filtering to meet discharge standards, resulting in high treatment costs. Therefore, we have developed a system for the resource-based treatment of condensate wastewater generated from municipal sludge composting and fermentation to meet treatment needs. Utility Model Content

[0007] The purpose of this invention is to provide a condensate wastewater treatment system for municipal sludge composting and fermentation. The treated condensate wastewater is used as supplementary nitrogen fertilizer and mixed with garden greening water for irrigation. The humic acid-containing precipitate produced during the treatment process is recycled for composting and fermentation, thereby enhancing the sludge fertility and achieving the goal of resource utilization.

[0008] The technical solution of this utility model is:

[0009] A system for treating condensate wastewater generated from municipal sludge composting and fermentation includes a mixing sedimentation tank, an ozone reactor, and a dilution tank. The mixing sedimentation tank is equipped with a dosing port and a wastewater inlet. The condensate wastewater enters the mixing sedimentation tank through the wastewater inlet. A chemical agent, calcium hydroxide solution, is added to the mixing sedimentation tank through the dosing port. The wastewater outlet of the mixing sedimentation tank is connected to the inlet of the ozone reactor through a pipe. The outlet of the ozone reactor is connected to the inlet of the dilution tank through a pipe. The dilution tank contains effluent, which is treated effluent from a wastewater treatment plant that meets emission standards.

[0010] Furthermore, the wastewater, after being mixed and settled in the mixing sedimentation tank, enters the ozone reaction device through a pipeline;

[0011] Furthermore, the mixing sedimentation tank is equipped with a stirring device, which mixes the condensed waste liquid with the reagent.

[0012] Furthermore, the mixing sedimentation tank is equipped with a detector, including a pH detector, which detects the pH value of the wastewater. If the wastewater is alkaline, it is discharged into the ozone reaction device.

[0013] Furthermore, the mixing sedimentation tank is equipped with a sludge outlet, through which the sludge after reaction and sedimentation enters the feed end of the sludge composting system.

[0014] Furthermore, the bottom of the mixing sedimentation tank is conical, and the sludge outlet is located at the bottom of the cone.

[0015] Furthermore, the wastewater inlet is located on the side of the mixing sedimentation tank, the chemical dosing port is located at the top of the mixing sedimentation tank, and the wastewater inlet is adjacent to the chemical dosing port;

[0016] Furthermore, the ozone reactor is equipped with an ozone port, through which ozone is supplied to the ozone reactor and reacts with the wastewater.

[0017] Furthermore, the ozone reaction device is equipped with a detector, including a pH detector, which detects the pH of the wastewater. If the pH is alkaline, the wastewater is discharged into a dilution tank.

[0018] Furthermore, the ratio of wastewater to effluent added in the dilution tank is 1:10+, and the effluent is treated effluent from the wastewater treatment plant that meets the standards.

[0019] The advantages and positive effects of this utility model are:

[0020] The municipal sludge composting and fermentation system for treating condensate wastewater does not completely treat the wastewater to meet discharge standards. Instead, it treats the wastewater for use as landscaping water. The treatment process is simple and low-cost. The treated wastewater is used as supplementary nitrogen fertilizer, mixed with the landscaping water for irrigation. The humic acid-containing precipitate produced during this process is recycled for composting and fermentation, thereby enhancing the sludge's fertility. This technology achieves the goal of resource-based treatment of condensate wastewater. Specifically:

[0021] (1) The condensed waste liquid reacts with calcium hydroxide in a mixed sedimentation tank to produce precipitate, which removes some color and reduces the concentration of CODcr and other substances in the waste liquid. The precipitate containing humus and calcium, along with low-content heavy metals, is sprayed back into the sludge composting system for further fermentation, thereby enhancing the fertilizer effect of the fermented material and providing effective nutrients for the improvement of saline-alkali land and acidic soil. The wastewater enters the ozone reactor for further treatment.

[0022] Furthermore, after adding calcium hydroxide, the waste liquid becomes alkaline. In an alkaline environment, ozone exhibits stronger oxidizing properties. During water treatment, the decomposition rate of ozone increases with the increase of pH value. For every unit increase in pH, the decomposition rate of ozone is about 3 times faster, resulting in the generation of more hydroxyl radicals in an alkaline environment. Therefore, the reaction between ozone and organic matter is more effective, enhancing the oxidizing capacity of ozone, shortening the reaction time, and reducing investment costs.

[0023] (2) After the wastewater enters the ozone reactor, ozone has strong oxidizing and decolorizing properties. Especially in an alkaline environment, it generates more hydroxyl radicals, which can degrade the concentration of CODcr, ammonia nitrogen, nitrogen, phosphorus, etc. in the wastewater. Ozone also has a strong bactericidal effect, which can remove fecal coliforms and roundworm eggs from the wastewater. After contact with ozone, the pH value of the wastewater drops from 11 to 8, reducing the neutralization cost. At the same time, a stirring device is set up to further improve the reaction efficiency and reaction effect.

[0024] (3) After treatment by the ozone reactor, the wastewater enters the dilution tank, where it is mixed with the effluent at a ratio of 1:10. The effluent is treated wastewater that meets the standards after treatment at the wastewater treatment plant. After mixing, the conductivity, CODcr, etc., meet the requirements for irrigation water for landscaping. Furthermore, plants can utilize the nitrogen in the nitrates to synthesize amino acids and proteins, promoting photosynthesis. After the treated wastewater is diluted 10 times, the nitrogen content in the nitrates applied per square meter is (0.1-0.3) grams. Herbaceous plants require 0.3-0.5 grams of nitrogen fertilizer per square meter, so the nitrates will not accumulate in the soil and can be fully utilized.

[0025] Other wastewater parameters, including CODcr and ammonia nitrogen concentrations, within the mixing sedimentation tank and ozone reactor are measured in the laboratory. A pH meter is installed within the mixing sedimentation tank and ozone reactor to facilitate pH value monitoring. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the condensate waste liquid treatment system generated from municipal sludge composting and fermentation according to this utility model.

[0027] In the picture:

[0028] 1. Mixing sedimentation tank; 2. Ozone reactor; 3. Dilution tank;

[0029] 1-1. Wastewater inlet; 1-2. Chemical dosing port. Detailed Implementation

[0030] Example 1:

[0031] A system for treating condensate wastewater generated from municipal sludge composting and fermentation includes a mixing sedimentation tank 1, an ozone reactor 2, and a dilution tank 3. The mixing sedimentation tank 1 is equipped with a dosing port 1-2 and a wastewater inlet 1-1. The condensate wastewater enters the mixing sedimentation tank 1 through the wastewater inlet 1-1. A chemical agent, calcium hydroxide solution, is added to the mixing sedimentation tank 1 through the dosing port 1-2. The wastewater outlet of the mixing sedimentation tank 1 is connected to the inlet of the ozone reactor 2 through a pipe. The outlet of the ozone reactor 2 is connected to the inlet of the dilution tank 3 through a pipe. The dilution tank 3 contains effluent, which is treated effluent from a wastewater treatment plant that meets the standards.

[0032] The condensate from the municipal sludge composting fermentation is fed into the mixing sedimentation tank 1 through the wastewater inlet 1-1. At the same time, calcium hydroxide solution is added to the mixing sedimentation tank 1. Since the wastewater inlet 1-1 is located on the side of the mixing sedimentation tank 1 and the chemical dosing port 1-2 is located at the top of the mixing sedimentation tank 1, and the wastewater inlet 1-1 is adjacent to the chemical dosing port 1-2, the chemicals are flushed away and mixed by the wastewater, resulting in good mixing effect. Combined with the stirring device, this improves the reaction effect.

[0033] Wastewater reacts with calcium hydroxide in the mixing sedimentation tank 1 to produce precipitate, which removes some color and reduces the concentration of CODcr and other substances in the wastewater. The resulting precipitate containing humus and calcium, along with low levels of heavy metals, is injected back into the sludge composting system for further fermentation, thereby enhancing the fertility of the fermented materials and providing effective nutrients for the improvement of saline-alkali land and acidic soil. The wastewater then enters the ozone reactor 2 for further treatment.

[0034] Furthermore, after adding calcium hydroxide, the waste liquid becomes alkaline. In an alkaline environment, ozone exhibits stronger oxidizing properties. During water treatment, the decomposition rate of ozone increases with the increase of pH value. For every unit increase in pH, the decomposition rate of ozone is about 3 times faster, resulting in the generation of more hydroxyl radicals in an alkaline environment. Therefore, the reaction between ozone and organic matter is more effective, enhancing the oxidizing capacity of ozone, shortening the reaction time, and reducing investment costs.

[0035] After mixing, sedimentation occurs. Since the bottom of the mixing sedimentation tank 1 is conical with a sludge outlet, the sediment is easily discharged. The sludge after reaction and sedimentation enters the feed end of the sludge composting system through the sludge outlet. After the wastewater from mixing and sedimentation in the mixing sedimentation tank 1 passes pH testing, it enters the ozone reactor 2 through a pipeline. The ozone reactor 2 has an ozone port, through which ozone is supplied to the ozone reactor 2, where it reacts with the wastewater.

[0036] After the wastewater enters the ozone reactor 2, ozone has strong oxidizing and decolorizing properties. Especially in an alkaline environment, it generates more hydroxyl radicals, which can degrade the concentration of CODcr, ammonia nitrogen, nitrogen, phosphorus, etc. in the wastewater. Ozone also has a strong bactericidal effect, which can remove fecal coliforms and roundworm eggs from the wastewater. After contact with ozone, the pH value of the wastewater drops from 11 to 8, reducing the neutralization cost.

[0037] After the condensate wastewater is treated by the ozone reaction device 2, the water quality of the treated water is shown in Table 1 (effluent column). Compared with the basic control items in Tianjin Municipal Standard "Requirements for Irrigation Water Quality for Landscape Greening" DB12 / T 857-2019, its conductivity is higher. Compared with the selective control items in the above standard, heavy metals were not detected.

[0038] Furthermore, the indicators before and after processing are as follows:

[0039] Table 1: Indicators of condensate waste liquid before and after treatment in this embodiment

[0040] Pollution parameters Water ingress Out of water pH value 8.05 8.25 Electrical conductivity (µs / cm) 9270 8600 CODcr (mg / L) 1470 90 Ammonia nitrogen (mg / L) 1010 421 Total nitrogen (mg / L) 1680 1380 Total phosphorus (mg / L) 1.55 0.06 SS (mg / L) 28 52 Fluoride ions (mg / L) 2.12 Not detected Sulfate ions (mg / L) 259 267 Sulfite ions (mg / L) Not detected Not detected Chloride (mg / L) 11.6 101 Nitrate ions (mg / L) 780 4850 Nitrite ions (mg / L) 2050 18.1 Cadmium (mg / L) 0.05 Not detected Chromium (mg / L) 0.03 Not detected Mercury (ug / L) 0.22 Not detected Arsenic (ug / L) 6.37 Not detected Lead (mg / L) 0.2 Not detected

[0041] The ozone reactor 2 is commercially available. After the ozone reactor 2 reacts, if the pH value is alkaline, it is discharged into the dilution tank 3. The volume ratio of the dilution tank 3 to the ozone reactor 2 is less than 1:10, and the ratio of wastewater to effluent added to the dilution tank 3 is 1:10. The effluent is compliant effluent from a domestic wastewater treatment plant. After being diluted 10 times in the dilution tank 3, the conductivity becomes approximately 860 μS / cm, meeting the high-quality utilization standard. Other indicators safely meet the standard requirements, and plants can utilize the nitrogen in the nitrate to synthesize amino acids and proteins, promoting photosynthesis. After the treated wastewater is diluted 10 times, the nitrogen content in the nitrate applied per square meter is (0.1-0.3) grams. Herbaceous plants require 0.3-0.5 grams of nitrogen fertilizer per square meter, so the nitrate will not accumulate in the soil and can be completely utilized. A stirring device is installed to further improve the reaction efficiency and effect.

[0042] Through subsequent monitoring, after dilution with 10 times the amount of water used for greening, the water volume for greening irrigation was calculated as (1-3) L / m². 2 .d Calculation (referring to the water consumption for greening irrigation in the "Code for Design of Building Water Supply and Drainage" GB50015-2003), the amount of nitrate applied is (0.441-1.323) g / m 2 This translates to (0.1-0.3) g / m³ of nitrogen fertilizer. 2 If this nitrate is applied entirely to the soil and not utilized by plants, the increase in soil nitrate levels is (0.25-0.74) mg / kg, which has a negligible impact on the soil. The treated condensate, after dilution, has a total nitrogen concentration of 125 mg / L, replacing (0.125-0.376) g / m³ of nitrogen fertilizer. 2 Therefore, adopting this application is cost-effective, quick to produce results, easy to operate, and feasible.

[0043] Comparative Example 1: The untreated condensate wastewater, compared to the basic control items in Tianjin Municipal Standard "Quality Requirements for Irrigation Water for Landscaping" DB12 / T 857-2019, has a relatively high conductivity. After dilution 10 times, the conductivity becomes approximately 927 μS / cm, meeting the high-quality utilization standard. However, compared to the selective control items in the above standard, heavy metals do not meet the requirements. Even after a 10-fold dilution, mercury and arsenic heavy metals still do not meet the utilization requirements. Based on these considerations, to achieve safe utilization, the condensate wastewater must undergo pretreatment before being mixed with landscaping water for irrigation. Therefore, the condensate wastewater treatment system generated from municipal sludge composting fermentation has a simple structure and good effect.

[0044] The above description provides a detailed account of one embodiment of the present invention. However, this description is merely a preferred embodiment and should not be construed as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the claims of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A system for treating condensate wastewater generated from municipal sludge composting and fermentation, characterized in that: The system includes a mixing sedimentation tank, an ozone reactor, and a dilution tank. The mixing sedimentation tank is equipped with a dosing port and a wastewater inlet. Condensed wastewater enters the mixing sedimentation tank through the wastewater inlet. A chemical is added to the mixing sedimentation tank through the dosing port. The wastewater outlet of the mixing sedimentation tank is connected to the inlet of the ozone reactor through a pipe. The outlet of the ozone reactor is connected to the inlet of the dilution tank through a pipe. The mixing sedimentation tank is equipped with a detector, including a pH detector. The pH value of the wastewater is detected by the pH detector. If the wastewater is alkaline, it is discharged into the ozone reaction device. The ozone reaction device is equipped with a detector, including a pH detector. The pH of the wastewater is detected by the pH detector. If the wastewater is alkaline, it is discharged into the dilution tank. The pH value of the wastewater after being exposed to ozone dropped from 11 to 8.

2. The condensate wastewater treatment system for municipal sludge composting and fermentation according to claim 1, characterized in that: The mixing sedimentation tank is equipped with a stirring device, which mixes the condensed waste liquid with the reagent.

3. A condensate wastewater treatment system for municipal sludge composting and fermentation according to claim 1 or 2, characterized in that: The mixing sedimentation tank is equipped with a sludge outlet. The sludge after reaction and sedimentation enters the feed end of the sludge composting system through the sludge outlet. The dilution tank contains tailwater.

4. The condensate wastewater treatment system for municipal sludge composting and fermentation according to claim 3, characterized in that: The bottom of the mixing sedimentation tank is conical, and a sludge outlet is provided at the bottom of the cone.

5. The condensate wastewater treatment system for municipal sludge composting and fermentation according to claim 4, characterized in that: The wastewater inlet is located on the side of the mixing sedimentation tank, and the chemical dosing port is located at the top of the mixing sedimentation tank. The wastewater inlet is adjacent to the chemical dosing port.

6. The condensate wastewater treatment system for municipal sludge composting and fermentation according to claim 5, characterized in that: The ozone reactor is equipped with an ozone port, through which ozone is supplied to the ozone reactor.

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