A method for the resource utilization of stratified biofilm-coated sludge granules

Abstract

This invention relates to a layered biofilm-based method for the resource recovery of granular sludge, comprising the following steps: preparing a core of construction waste and a fiber material; uniformly spraying EM (Effective Microorganisms) solution onto the surface of the core of the construction waste; placing the EM-sprayed core of the construction waste into a sludge tank for biofilm formation; then rolling the core of the construction waste onto the fiber material to ensure that the surface of the core of the construction waste after biofilm formation is fully coated with the fiber material; spraying the core of the construction waste with EM solution again and placing it back into the sludge tank for biofilm formation; repeating the steps of spraying EM solution, biofilm formation, and coating with fiber material multiple times; and finally drying. This invention is the first to use a layered biofilm-based, dewatering-free method to granulate sludge, solving the problems of high energy consumption, complex equipment and processes, serious environmental pollution, and difficult treatment associated with traditional sludge thermal drying and other dewatering treatments.

Description

Technical Field

[0001] This invention relates to the field of environmental protection, and in particular to a method for the resource utilization of stratified biofilm-type sludge particles. Background Technology

[0002] In 2015, the "Ten Measures for Water Pollution Prevention and Control" explicitly required the treatment and disposal of sludge: "Sludge generated by sewage treatment facilities should be stabilized, rendered harmless, and recycled. Sludge that fails to meet treatment standards is prohibited from entering arable land. Illegal sludge dumping sites must be shut down. Existing sludge treatment and disposal facilities should have basically completed their upgrades to meet standards by the end of 2017, and the harmless treatment and disposal rate of sludge in prefecture-level and above cities should reach over 90% by the end of 2020." Sludge contains a large amount of beneficial components needed for plant growth, such as nitrogen, phosphorus, potassium, calcium, magnesium, zinc, copper, iron, and sulfur, which can be absorbed and utilized by plants. This means that while sludge is solid waste, it also possesses enormous resource potential.

[0003] The moisture content of sludge is mostly above 90%. This high moisture content not only increases the volume and mass of the sludge significantly, causing difficulties in subsequent transportation, requiring large-capacity treatment equipment, and resulting in poor economic efficiency, but also makes it difficult for the moisture in the sludge to evaporate into crystalline form under sunlight. Even with sun exposure, only a small amount of crystalline water can be evaporated. Therefore, current sludge resource utilization treatments all involve dewatering. In China, most sludge dewatering equipment is used, directly employing thermal energy for drying. This method has limited processing capacity, high energy consumption, high processing costs, and inevitably leads to secondary pollution. Summary of the Invention

[0004] In view of the above-mentioned problems in the existing technology, the technical problem to be solved by the present invention is: how to carry out reasonable and environmentally friendly disposal and resource utilization of sludge without reducing the water content of sludge.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a method for the resource utilization of stratified biofilm-type sludge particles, comprising the following steps:

[0006] S1: Preparation of construction waste core: Using construction waste as raw material, the construction waste is crushed and sieved into particles with a diameter of ≤5mm to obtain the construction waste core. The particle size of the construction waste can be 5mm, 4mm, 3mm, 2mm or 1mm.

[0007] S2: Preparation of fiber material: Garden plant waste is shaved into fragments with a length of 4-9cm, a width of 2-5cm, and a thickness of 0.5-2cm. The fragments are then crushed into fiber material with a particle size ≤2mm, dried, and the moisture content is controlled to be no higher than 10%. The size of the fragments can be selected, with a length of 4cm, 5cm, 6cm, 7cm, 8cm, or 9cm, a width of 2cm, 3cm, 4cm, or 5cm, and a thickness of 0.5cm, 1.0cm, 1.5cm, or 2cm. The particle size of the fiber material can be 2mm, 1.5mm, 1mm, or 0.5mm.

[0008] S3: Mix EM agent and water to prepare an EM solution with a mass fraction of 0.16-0.32%, which is the EM solution for biofilm attachment. The mass fraction of the EM solution can be 0.16%, 0.18%, 0.2%, 0.22%, 0.25%, 0.28%, 0.3%, or 0.32%.

[0009] S4: Spray EM bacterial solution evenly onto the core surface of construction waste.

[0010] S5: After spraying the construction waste core with EM bacterial solution, put it into the sludge tank to form a biofilm. Stir it evenly so that the construction waste core is fully coated with the sludge biofilm. The sludge tank contains undehydrated sludge.

[0011] S6: The construction waste core after S5 treatment is placed on the fiber material and rolled to ensure that the surface of the construction waste core after being coated with sludge film is fully wrapped by the fiber material.

[0012] S7: Spray EM bacterial solution onto the core of the construction waste after S6 treatment and put it back into the sludge tank for biofilm formation treatment.

[0013] S8: After repeating steps S6 and S7 multiple times, the organic matrix is ​​obtained after drying.

[0014] Preferably, the fragments in S2 have a length of 6cm, a width of 5cm, and a thickness of 1cm.

[0015] Preferably, the mass fraction of EM agent in step S3 is 0.25%.

[0016] Compared with the prior art, the present invention has at least the following advantages:

[0017] 1. This invention is the first to use a layered film-coating method to treat sludge in a granular form without dewatering, which solves the problems of high energy consumption, complex equipment and processes, serious environmental pollution and difficult treatment caused by traditional sludge thermal drying and other dewatering treatments.

[0018] 2. The stratified biofilm formation of EM bacteria, fiber materials, and sludge allows for full contact between the sludge and EM bacteria and fibers, enhancing biofilm strength and eliminating the need for secondary fermentation. It also replenishes the organic components in the sludge, resulting in more complete sludge degradation and significantly improving the efficiency of resource recovery.

[0019] 3. This invention reuses construction waste (which mainly includes: mud, waste bricks and stones, asphalt, waste glass, waste concrete, etc.) and agricultural and forestry waste (straw, fallen leaves, etc.), realizing the recycling of resources and turning waste into treasure.

[0020] 4. The method provided by this invention enables the resource recovery of sludge from wastewater treatment plants without dewatering treatment (the sludge moisture content is mostly above 90%). At the same time, it adopts a layered biofilm model of microorganisms, fiber materials and sludge, which allows the microorganisms, fiber materials and sludge to come into full contact without any mixing measures, which greatly improves the efficiency of resource recovery. Detailed Implementation

[0021] The present invention will now be described in further detail.

[0022] A method for the resource utilization of stratified biofilm-type sludge granules includes the following steps:

[0023] S1: Preparation of construction waste core: Construction waste is used as raw material, and the waste is crushed and sieved into particles with a diameter of ≤5mm to obtain the construction waste core. The inventors found through experiments that when the particle size of the crushed construction waste is greater than 5mm, the biofilm formation effect is poor when placed in the sludge tank in S5.

[0024] S2: Fiber material preparation: Garden plant waste is shredded into fragments with a length of 4-9cm, a width of 2-5cm, and a thickness of 0.5-2cm; the fragments are then crushed into fiber materials with a particle size ≤2mm by a dry and wet material pulverizer, and dried to control the moisture content to not exceed 10%, thus obtaining the fiber material.

[0025] The selection of fragment size is mainly to better crush the material and obtain fiber material with a particle size ≤2mm. Experiments have shown that fiber material with a particle size ≤2mm can more fully coat the core surface of construction waste in S6.

[0026] In addition, controlling the moisture content of fiber materials with a particle size of ≤2mm to no more than 10% can make the fiber materials disperse evenly and non-sticky, and facilitate the full wrapping of the core surface of construction waste.

[0027] S3: Mix EM agent with water to prepare an EM solution with a mass fraction of 0.16-0.32%, which is the EM solution for biofilm formation. This mass fraction of 0.16-0.32% is the optimal concentration of EM solution; too high or too low a concentration is not conducive to the effectiveness of the microorganisms.

[0028] S4: Spray EM bacterial solution evenly onto the core surface of construction waste.

[0029] S5: After spraying the construction waste core with EM bacterial solution, put it into the sludge tank to form a biofilm. Stir it evenly so that the construction waste core is fully coated with sludge film. The sludge tank stores undried sludge (sludge with a moisture content of mostly above 90%).

[0030] S6: The construction waste core after S5 treatment is placed on the fiber material and rolled to ensure that the surface of the construction waste core after being coated with sludge film is fully wrapped by the fiber material.

[0031] S7: Spray EM bacterial solution onto the core of the construction waste after S6 treatment and put it back into the sludge tank for biofilm formation treatment.

[0032] S8: After repeating steps S6 and S7 multiple times, the organic matrix is ​​obtained after drying.

[0033] test:

[0034] 1. Plant cultivation experiment

[0035] Using ordinary substrates (a mixture of peat and soil in a 1:3 ratio) and the sludge substrate prepared in this invention, i.e., organic substrates, as substrate raw materials, a planting experiment was conducted with Schefflera heptaphylla as plant material. The experiment was conducted in Shenzhen, Guangdong Province, and lasted for 2 months. Before the experiment, the substrate bulk density, porosity, water holding capacity, organic matter content, cation exchange capacity, pH, air permeability, and permeability coefficient were tested. After the experiment, biomass, transpiration rate, net photosynthetic rate, and SPAD content were tested.

[0036] Table 1 Physicochemical properties of the two matrices

[0037]

[0038] As shown in Table 1, the bulk density, porosity, water retention, organic matter content, cation exchange capacity, and pH performance of the sludge substrate are similar to those of ordinary substrates. However, its air permeability and permeability coefficient are higher than those of ordinary substrates.

[0039] Table 2 Physiological Indicators of Schefflera heptaphylla

[0040]

[0041] Two months after planting, the results showed that, compared with ordinary substrates, the sludge substrate for planting schefflera had a larger biomass, higher transpiration rate, net photosynthetic rate, and higher SPAD content, indicating that the sludge substrate was more conducive to the growth of schefflera.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for the resource utilization of stratified biofilm-coated sludge granules, characterized in that: Includes the following steps: S1: Preparation of construction waste core: Construction waste is used as raw material, and the construction waste is crushed and sieved into particles with a particle size of ≤5mm to obtain the construction waste core; S2: Preparation of fiber materials: Garden plant waste is shaved into fragments with a length of 4-9cm, a width of 2-5cm, and a thickness of 0.5-2cm; then the fragments are crushed into fiber materials with a particle size ≤2mm, and dried to control the moisture content to be no higher than 10%, thus obtaining the fiber materials. S3: Mix EM agent with water to prepare an EM solution with a mass fraction of 0.16-0.32%, which is the EM solution for biofilm formation. S4: Spray EM bacterial solution evenly onto the core surface of construction waste; S5: After spraying the construction waste core with EM bacterial solution, put it into the sludge tank to form a film, stir it evenly, so that the construction waste core is fully coated with sludge film, and the sludge tank stores undried sludge. S6: The construction waste core after S5 treatment is placed on the fiber material and rolled to ensure that the surface of the construction waste core after being coated with sludge film is fully wrapped by the fiber material. S7: Spray EM bacterial solution onto the core of the construction waste after S6 treatment and put it back into the sludge tank for biofilm treatment. S8: After repeating steps S6 and S7 multiple times, the organic matrix is ​​obtained after drying.

2. The method for resource utilization of stratified biofilm-type sludge granules as described in claim 1, characterized in that: The fragments in S2 have a length of 6cm, a width of 5cm, and a thickness of 1cm.

3. The method for resource utilization of stratified biofilm-type sludge granules as described in claim 2, characterized in that: The mass fraction of EM bacterial solution in S3 is 0.25%.

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