Wastewater treatment process based on sludge biochar carrier

Abstract

This invention discloses a wastewater treatment process based on sludge biochar carrier, belonging to the field of wastewater treatment technology. The process consists of a first treatment stage, a second treatment stage, a third treatment stage, and a sand filtration stage. Wastewater undergoes aerobic treatment with aeration in the first treatment stage, simultaneous nitrification and denitrification with aeration in the second treatment stage, and treatment of total nitrogen (TN) in the third treatment stage. Finally, suspended solids (SS) are removed through sand filtration. The total retention time is controlled at 6-12 hours. This scheme employs a three-stage biofilm treatment to achieve aerobic treatment and simultaneous nitrification and denitrification of wastewater, resulting in high treatment efficiency. It is particularly effective for treating low C / N wastewater, eliminating the need for carbon source addition. This invention features a simple and efficient process with low energy consumption and a small footprint, making it particularly suitable for small-scale urban wastewater, rural wastewater, and the treatment of black and odorous water environments.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, and in particular relates to a wastewater treatment process based on sludge biochar carrier. Background Technology

[0002] Currently, low C / N ratios are a common problem in the influent of wastewater treatment plants in my country. Surveys have found that 80% of wastewater treatment plants have an influent BOD5 / TN ratio < 3.6, indicating insufficient denitrification carbon sources for most plants. This makes it difficult for the effluent quality to meet increasingly stringent discharge standards. While adding external carbon sources, adjusting process operating parameters, and optimizing the distribution of carbon sources in the raw wastewater can effectively improve the denitrification effect of low C / N wastewater, the influent quality varies greatly depending on the region where the urban wastewater treatment plant is located. Even with the same C / N value, differences in the availability of carbon sources in the raw water can lead to variations in denitrification efficiency. Therefore, it is necessary to further classify the carbon sources in wastewater and clarify the utilization efficiency of various carbon sources in order to effectively improve the denitrification effect of urban wastewater treatment plants in my country.

[0003] Meanwhile, against the backdrop of economic development and population mobility between urban and rural areas, my country's rural domestic sewage treatment technology needs to keep pace with the times and explore technical routes adapted to local conditions. Currently, my country's village and town sewage treatment models include decentralized treatment, centralized village treatment, and integration into urban drainage networks. Typically, small settlements with one or a few households are suitable for decentralized small-scale sewage treatment equipment or natural treatment models, while larger villages can build village-level sewage treatment stations for centralized treatment. Villages near towns can discharge sewage into urban sewage networks for transport to urban sewage treatment plants. According to data from the Ministry of Housing and Urban-Rural Development, the urban sewage treatment rate exceeded 97% in 2020, but rural sewage treatment still has significant shortcomings, with a treatment rate of only 28% in 2021. The slow progress in rural sewage treatment is due to factors such as high construction costs and difficulties in operation and maintenance of sewage treatment facilities.

[0004] Conventional wastewater treatment processes require the addition of carbon sources for urban low C / N wastewater treatment, resulting in high treatment costs. In addition, rural domestic sewage is dispersed, leading to higher construction and operation costs for wastewater treatment facilities, and also occupying a large amount of land resources. Summary of the Invention

[0005] The purpose of this invention is to provide a wastewater treatment process based on sludge biochar carrier, which aims to solve the technical problems of high cost and difficult maintenance of wastewater treatment facilities in the prior art, which have led to the slow development of rural wastewater treatment.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A wastewater treatment process based on sludge biochar carrier is divided into a first treatment section, a second treatment section, a third treatment section, and a sand filtration section. The first treatment section is filled with a first packing material for aerobic aeration of wastewater. The second treatment section is filled with a second packing material for simultaneous nitrification and denitrification of wastewater through aeration. The third treatment section is filled with a third packing material for treating total nitrogen (TN) in wastewater. Both the first and second treatment sections are equipped with aeration components.

[0008] Wastewater flows sequentially through the first treatment section, the second treatment section, the third treatment section, and the sand filtration section, with the total retention time controlled at 6-12 hours.

[0009] Preferably, the first filler material inside the first treatment section is a sludge biochar carrier material, and the surface of the sludge biochar carrier is covered with an aerobic biological layer; the sludge biochar carrier material is solidified from sludge biochar, binder, foaming agent, adsorbent, and reinforcing fiber, with a particle size of 1-2 cm and a specific gravity of 0.8-1 g / cm3; the filling rate of the first filler material in the first treatment section is 20-30%, the dissolved oxygen is controlled at 2-3 mg / L; and the wastewater retention time in the first treatment section is controlled at 2-4 hours.

[0010] Preferably, the second packing material inside the second treatment section uses sludge biochar-sulfur-based mineral carrier material as its core. This is achieved by sequentially coating the surface of the sludge biochar-sulfur-based mineral carrier material with a sulfur autotrophic denitrifying bacteria layer and an aerobic microbial layer, with the aerobic microbial layer covering the outside of the sulfur autotrophic denitrifying bacteria layer. The sludge biochar-sulfur-based mineral carrier material is solidified from sludge-based biochar, sulfur-based mineral materials, binder, foaming agent, adsorbent, and reinforcing fibers, with a particle size of 1-2 cm and a specific gravity of 1-1.2 g / cm³. The filling rate of the second packing material in the second treatment section is 30-40%, dissolved oxygen is controlled at 1-2 mg / L, and the wastewater retention time in the second treatment section is controlled at 3-5 hours.

[0011] Preferably, the third packing material inside the third treatment section uses sludge biochar-sulfur-based mineral carrier material as its core, and is coated with a layer of sulfur autotrophic denitrifying bacteria. The sludge biochar-sulfur-based mineral carrier material is solidified from sludge-based biochar, sulfur-based mineral materials, binder, foaming agent, adsorbent, and reinforcing fibers, with a particle size of 1-2 cm and a specific gravity of 1.2-1.5 g / cm³. 3 The third packing material has a filling rate of 60-80% in the third treatment section, dissolved oxygen is controlled at 0.2-0.5 mg / L, and the retention time of wastewater in the third treatment section is controlled at 1-3 hours.

[0012] Preferably, the interior of the sand filter section is filled with quartz sand with a particle size of 0.5-1mm; the residence time of wastewater in the sand filter section is controlled at 0.01-0.5 hours.

[0013] Preferably, when the effluent concentration increases after the wastewater has passed through the first treatment section, the second treatment section, the third treatment section, and the sand filtration section, the reflux system is activated; the reflux system includes a reflux pipe and a reflux pump, the inlet end of the reflux pipe is connected to the outlet end of the third treatment section, the outlet end of the reflux pipe is connected to the inlet of the first treatment section, and the reflux pump is installed on the reflux pipe.

[0014] Preferably, the first treatment section, the second treatment section, the third treatment section and the sand filter section are integrated into the box body from top to bottom. The top of the first treatment section, the second treatment section, the third treatment section and the sand filter section are all provided with partitions, and the partitions are provided with water passage holes. The top of the box body is provided with a water inlet and the bottom is provided with a water outlet.

[0015] Preferably, the diameter of the water passage hole on the partition is 0.5-1cm.

[0016] Preferably, the aeration component is an aeration disc, which is respectively disposed at the bottom of the first treatment section and the second treatment section, and the aeration disc is connected to the blower through a duct.

[0017] Preferably, the air duct is equipped with an air volume control valve, and the bottom of the housing is equipped with a water outlet control valve.

[0018] The beneficial effects of adopting the above technical solution are as follows:

[0019] 1. This invention employs a three-stage biofilm treatment process. By adjusting and controlling the composition, specific gravity, filling rate, aeration rate, and dissolved oxygen of the filling carrier material in each treatment stage, aerobic treatment, simultaneous nitrification and denitrification treatment, and denitrification treatment are achieved, resulting in high treatment efficiency.

[0020] 2. This invention can utilize simultaneous nitrification and sulfur autotrophic denitrification to treat low C / N wastewater without the need for carbon source addition.

[0021] 3. This invention can achieve aerobic treatment, simultaneous nitrification and denitrification treatment, and denitrification treatment in the same equipment, with high treatment efficiency, compact equipment, high integration, and small footprint.

[0022] 4. This invention can activate external reflux when the effluent concentration is high, thereby improving treatment efficiency.

[0023] 5. The present invention has a simple process, compact structure, is easy to control, has low manufacturing cost, and is suitable for large-scale production and application. Attached Figure Description

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0025] Figure 1 This is a schematic diagram of the water treatment reactor used in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the internal structure of the packing material used in this embodiment of the invention;

[0027] Figure 3 This is a schematic diagram of the internal structure of the packing material 2 used in the embodiments of the present invention;

[0028] Figure 4 This is a schematic diagram of the internal structure of packing material three used in the embodiments of the present invention;

[0029] In the diagram: 00, Box body; 1, First treatment section; 2, Second treatment section; 3, Third treatment section; 4, Sand filter section; 5, Baffle plate; 6-1, First packing material; 6-2, Second packing material; 6-3, Third packing material; 7, Blower; 8, Air volume control valve; 9, Aeration disc; 10, Return pump; 11, Effluent control valve; 12, Return pipe;

[0030] 60-Sulfur-based mineral materials, 61-Sludge-based biochar, 62-Binder, 63-Functional materials, 64-Porous channels, 65-Aerobic microbial layer, 66-Aerobic microorganisms, 67-Bio-adhesive, 68-Anaerobic microbial layer, 69-Anaerobic microorganisms. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] A wastewater treatment process based on sludge biochar carrier is divided into a first treatment stage 1, a second treatment stage 2, a third treatment stage 3, and a sand filtration stage 4 (e.g., Figure 1 As shown), the first treatment section 1 is filled with a first packing material 6-1 for aerobic aeration of wastewater, the second treatment section 2 is filled with a second packing material 6-2 for simultaneous nitrification and denitrification of wastewater, and the third treatment section 3 is filled with a third packing material 6-3 for treating TN in wastewater; both the first treatment section 1 and the second treatment section 2 are equipped with aeration components; wastewater flows sequentially through the first treatment section 1, the second treatment section 2, the third treatment section 3 and the sand filter section 4, with the total retention time controlled at 6-12 hours.

[0033] In specific implementation, the first packing material 6-1 inside the first treatment section 1 is a sludge biochar carrier material, and the surface of the sludge biochar carrier is covered with an aerobic biological layer; the sludge biochar carrier material is solidified from sludge biochar, binder, foaming agent, adsorbent, and reinforcing fiber, with a particle size of 1-2 cm and a specific gravity of 0.8-1 g / cm3; the filling rate of the first packing material 6-1 in the first treatment section 1 is 20-30%, and the dissolved oxygen is controlled at 2-3 mg / L; the retention time of sewage in the first treatment section 1 is controlled at 2-4 hours.

[0034] In specific implementation, the second packing material 6-2 inside the second treatment section 2 is a sludge biochar-sulfur-based mineral carrier material. The surface of the sludge biochar-sulfur-based mineral carrier material is sequentially coated with a sulfur autotrophic denitrifying bacteria layer and an aerobic microbial layer, with the aerobic microbial layer covering the outside of the sulfur autotrophic denitrifying bacteria layer. The sludge biochar-sulfur-based mineral carrier material is solidified from sludge-based biochar, sulfur-based mineral materials, binder, foaming agent, adsorbent, and reinforcing fiber, with a particle size of 1-2 cm and a specific gravity of 1-1.2 g / cm3. The filling rate of the second packing material 6-2 in the second treatment section 2 is 30-40%, the dissolved oxygen is controlled at 1-2 mg / L, and the retention time of wastewater in the second treatment section 2 is controlled at 3-5 hours.

[0035] In specific implementation, the third packing material 6-3 inside the third treatment section 3 is a sludge biochar-sulfur-based mineral carrier material, and the surface of the sludge biochar-sulfur-based mineral carrier material is coated with a sulfur autotrophic denitrifying bacteria layer; the sludge biochar-sulfur-based mineral carrier material is solidified from sludge-based biochar, sulfur-based mineral materials, binder, foaming agent, adsorbent, and reinforcing fibers, with a particle size of 1-2 cm and a specific gravity of 1.2-1.5 g / cm³. 3 The third packing material 6-3 has a filling rate of 60-80% in the third treatment section 3, dissolved oxygen is controlled at 0.2-0.5 mg / L, and the retention time of sewage in the third treatment section 3 is controlled at 1-3 hours.

[0036] In specific implementation, the interior of the sand filter section 4 is filled with quartz sand with a particle size of 0.5-1mm; the sewage is treated by removing suspended solids (SS) through the sand filter section, and the residence time of the sewage in the sand filter section 4 is controlled to be 0.01-0.5 hours.

[0037] In one specific embodiment of the present invention, such as Figure 1As shown, the first treatment section 1, the second treatment section 2, the third treatment section 3, and the sand filter section 4 are integrated from top to bottom within the housing 00, forming a water treatment reactor. Each of the first treatment section 1, the second treatment section 2, the third treatment section 3, and the sand filter section 4 is equipped with a baffle plate 5 at its top. The baffle plate 5 has water passage holes. The housing 00 has a water inlet at its top and a water outlet at its bottom. The diameter of the water passage holes on the baffle plate 5 is 0.5-1 cm. This design allows for a more compact overall structure and a smaller footprint.

[0038] In specific manufacturing, the aeration components are aeration discs 9, which are respectively installed at the bottom of the first treatment section 1 and the second treatment section 2. The aeration discs 9 are connected to the blower 7 via air ducts. The air ducts are equipped with airflow control valves 8, and the bottom of the housing 00 is equipped with a water outlet control valve 11. When the blower 7 is started, aeration and oxygenation are carried out in the first treatment section 1 and the second treatment section 2 through the aeration discs 9, maintaining the dissolved oxygen concentration in the water to meet the treatment requirements.

[0039] When the effluent concentration increases after wastewater has passed through the first treatment stage 1, the second treatment stage 2, the third treatment stage 3, and the sand filtration stage 4, the reflux system is activated. The reflux system includes a reflux pipe 12 and a reflux pump 10. The inlet end of the reflux pipe 12 is connected to the outlet end of the third treatment stage 3, and the outlet end of the reflux pipe 12 is connected to the inlet of the first treatment stage 1. The reflux pump 10 is mounted on the reflux pipe 12. When the effluent concentration after wastewater treatment by the reactor is high, activating the reflux pump allows the wastewater to flow back to the top of the tank, achieving wastewater recycling and thus enhancing the treatment effect.

[0040] Before the specific implementation of this invention, a first packing material, a second packing material, and a third packing material should be prepared in advance. The core sludge biochar carrier material of the first packing material 6-1 includes sludge-based biochar 61, binder 62, and functional material 63. The binder 62 includes organic binder and inorganic binder. The weight proportions of each component are as follows:

[0041] Sludge-based biochar: 100 parts;

[0042] Organic binder: 0.1-10 parts;

[0043] Inorganic binder: 1-20 parts;

[0044] Functional materials: 0.1-10 parts;

[0045] Water: 20-100 parts;

[0046] Functional materials include foaming agents, adsorbents, and reinforcing fibers, which are mixed in a weight ratio of 1:(10-100):(5-50).

[0047] The above components are mixed, shaped, hot-pressed and dried to produce sludge biochar carrier material. The sludge biochar carrier material is filled with pores 64 inside.

[0048] Both the second packing material 6-2 and the third packing material 6-3 are prepared from sludge biochar-sulfur-based mineral carrier material. The sludge biochar-sulfur-based mineral carrier material used includes sludge-based biochar, binder, sulfur-based mineral material, and functional material. The binder includes organic binder and inorganic binder. The weight proportions of each component are as follows:

[0049] Sludge-based biochar: 100 parts;

[0050] Organic binder: 0.1-10 parts;

[0051] Inorganic binder: 1-20 parts;

[0052] Sulfur-based mineral materials: 10-50 parts;

[0053] Functional materials: 0.1-10 parts;

[0054] Water: 20-100 parts;

[0055] Functional materials include foaming agents, adsorbents, and reinforcing fibers, which are mixed in a weight ratio of 1:(10-100):(5-50).

[0056] The above components are mixed, molded, hot-pressed, and dried to produce sludge biochar-sulfur-based mineral carrier material.

[0057] Figure 3 This is a schematic diagram of the internal structure of the second packing material 6-2. The internal sludge biochar-sulfur-based mineral carrier material includes sludge-based biochar 61, sulfur-based mineral material 60, binder 62, and functional material 63.

[0058] The inorganic binder is one or more of cement, lime, water glass, and gypsum; the organic binder is one or more of acrylate, methacrylate, hydroxymethyl acrylate, carboxymethyl acrylate, cellulose, methylcellulose, hydroxymethyl cellulose, and carboxymethyl cellulose.

[0059] The functional material is a mixture of foaming agent, adsorbent, and reinforcing fiber in a weight ratio of 1:(10-100):(5-50). The foaming agent is one or a mixture of two of aluminum powder and iron powder; the adsorbent is one or a mixture of more than two of zeolite powder, attapulgite powder, and sepiolite powder; the reinforcing fiber is one or a mixture of more than two of carbon fiber, glass fiber, basalt fiber, aramid fiber, orlon fiber, polyester fiber, nylon fiber, vinylon fiber, polypropylene fiber, and polyimide fiber, and the length of the reinforcing fiber is 1-10 mm.

[0060] Manufacturing Example 1:

[0061] The preparation method of sludge biochar carrier material A for the first packing material is as follows:

[0062] Step 1: Mix 100 parts of sludge-based biochar, 10 parts of cement, 0.15 parts of aluminum powder, 8 parts of zeolite powder, and 1 part of basalt fiber evenly.

[0063] Step 2: Add 50 parts of a 2% hydroxymethyl cellulose aqueous solution, stir and mix, and pour into a mold to solidify and shape;

[0064] Step 3: After natural curing for 24 hours, demold and then perform a constant temperature and pressure hydrothermal steam pressure reaction at 150℃ and 0.476MPa for 24 hours to foam and solidify, while simultaneously activating with steam heat.

[0065] Step 4: The carrier material prepared in step 3 is immersed in an aqueous solution containing 1% nitrifying bacteria and 1% guar gum for 60 minutes, then removed and sterilely vacuum dried at room temperature for 24 hours to obtain sludge biochar carrier material A with a particle size of 10 mm and a specific gravity of 0.8.

[0066] In step four, an aerobic microbial layer 65 is wrapped around the outside of the carrier material with a bio-adhesive 67. The aerobic microbial layer 65 is impregnated with aerobic microorganisms 66. In this manufacturing example, guar gum is a type of bio-adhesive.

[0067] The internal structure diagram of the sludge biochar carrier material in packing 6-1 prepared by the above method is shown below. Figure 2 As shown in the figure, the current state of filler 1 is only a schematic diagram, and the outlines of each layer are not limited to the shape shown in the figure.

[0068] Manufacturing Example 2:

[0069] The preparation method of the sludge biochar-sulfur-based mineral carrier material B for the second packing material is as follows:

[0070] Step 1: Mix 100 parts of sludge-based biochar, 10 parts of cement, 40 parts of sulfur-based mineral materials, 0.1 parts of aluminum powder, 8 parts of zeolite powder, and 1 part of basalt fiber evenly.

[0071] Step 2: Add 50 parts of a 2% hydroxymethyl cellulose aqueous solution, stir and mix, and pour into a mold to solidify and shape;

[0072] Step 3: After natural curing for 24 hours, demold and then perform a constant temperature and pressure hydrothermal steam pressure reaction at 150℃ and 0.476MPa for 24 hours to foam and solidify, while simultaneously activating with steam heat.

[0073] Step 4: The carrier material prepared in step 3 is immersed in an aqueous solution containing 1% sulfur autotrophic denitrifying bacteria and 1% guar gum for 60 minutes, then removed and sterilely vacuum dried at room temperature for 24 hours.

[0074] Step 5: The carrier material prepared in step 4 is immersed in an aqueous solution containing 1% nitrifying bacteria and 1% guar gum for 60 minutes, then removed and sterilely vacuum dried at room temperature for 24 hours to obtain sludge biochar-sulfur-based mineral carrier material B with a particle size of 10 mm and a specific gravity of 1.0.

[0075] The preparation process of filler material 2 6-2 involves sequentially wrapping an anaerobic microbial layer 68 and an aerobic microbial layer 65 around the outside of a sludge biochar-sulfur-based mineral carrier material through an anaerobic microbial layer 67. The inner anaerobic microbial layer 68 is impregnated with anaerobic microorganisms 69, and the outer aerobic microbial layer 65 is impregnated with aerobic microorganisms 66. Figure 3 As shown. Figure 3 The current state of the intermediate filler is only a schematic diagram; the outlines of each layer are not limited to the shapes shown in the diagram.

[0076] Manufacturing Example 3:

[0077] In this embodiment, the third filler is sludge biochar-sulfur-based mineral carrier material C, which is manufactured as follows:

[0078] Step 1: Mix 100 parts of sludge-based biochar, 10 parts of cement, 40 parts of sulfur-based mineral materials, 0.05 parts of aluminum powder, 8 parts of zeolite powder, and 1 part of basalt fiber evenly.

[0079] Step 2: Add 50 parts of a 2% hydroxymethyl cellulose aqueous solution, stir and mix, and pour into a mold to solidify and shape;

[0080] Step 3: After natural curing for 24 hours, demold and then perform a constant temperature and pressure hydrothermal steam pressure reaction at 150℃ and 0.476MPa for 24 hours to foam and solidify, while simultaneously activating with steam heat.

[0081] Step 4: The carrier material prepared in step 3 is immersed in an aqueous solution containing 1% sulfur autotrophic denitrifying bacteria and 1% guar gum for 60 minutes, then removed and sterilely vacuum dried at room temperature for 24 hours to obtain sludge biochar-sulfur-based mineral carrier material C with a particle size of 10 mm and a specific gravity of 1.3.

[0082] The preparation process of filler 2 6-3 involves wrapping an anaerobic microbial layer 68 around the exterior of a sludge biochar-sulfur-based mineral carrier material using a bio-adhesive 67. The anaerobic microbial layer 68 is impregnated with anaerobic microorganisms 69, such as... Figure 4 As shown. Figure 4 The current state of the middle packing material is only a schematic diagram; the outlines of each layer are not limited to the shapes shown in the diagram.

[0083] In the wastewater treatment process of this invention, the sludge-based biochar carrier material of the first packing in the first treatment section 1 is coated with an aerobic microbial layer, which is a strongly aerated aerobic treatment section, mainly treating COD, ammonia nitrogen, and phosphate in the wastewater; the sludge-based biochar-sulfur-based mineral carrier material of the second treatment section 2 is coated with a sulfur autotrophic denitrifying microbial layer and an aerobic microbial layer from the inside out, which is a moderately aerated simultaneous nitrification and denitrification treatment section, further treating COD, ammonia nitrogen, and phosphate, and simultaneously treating TN; the sludge-based biochar-sulfur-based mineral carrier material of the third treatment section 3 is coated with a sulfur autotrophic denitrifying microbial layer, without aeration, mainly treating TN; finally, the wastewater passes through the sand filtration section 4 to remove SS, and the effluent is disinfected before being discharged in compliance with standards.

[0084] The following are some specific application examples of this invention:

[0085] The manufacturers and specifications of the raw materials used in the preparation of the first, second, and third packing materials are as follows:

[0086] Cement: Silicate cement, Jiangnan Cement Plant, particle size 200 mesh;

[0087] Aluminum powder: Jinan Yinpeng Building Materials Co., Ltd., particle size 325 mesh;

[0088] Iron(III) oxide: Homemade;

[0089] Basalt fiber: Changzhou Zhuwei Building Materials Co., Ltd., 20mm long;

[0090] Sludge-based biochar: Carbonization treatment of residual sludge from a wastewater treatment plant in Ma'anshan, with a particle size of 200 mesh;

[0091] Zeolite powder: Ningbo Jiahe New Material Technology Co., Ltd., particle size 325 mesh;

[0092] The sulfur-based mineral material used is pyrite powder: Daye Jinpeng Friction Materials Co., Ltd., with a particle size of 200 mesh;

[0093] Sulfur-autotrophic denitrifying bacteria and nitrifying bacteria are both self-enriched, screened and cultivated in activated sludge of sewage treatment plants;

[0094] Hydroxymethyl cellulose and guar gum are both produced by Sinopharm Group;

[0095] Water: tap water.

[0096] Manufacturing Example 1

[0097] The manufacturing method of sludge biochar carrier material A, which serves as the core of the first packing material, is as follows:

[0098] Step 1: Mix 100 parts of sludge biochar, 10 parts of cement, 0.15 parts of aluminum powder, 8 parts of zeolite powder, and 1 part of basalt fiber evenly.

[0099] Step 2: Add 50 parts of a 2% hydroxymethyl cellulose aqueous solution, stir and mix, and pour into a mold to solidify and shape;

[0100] Step 3: After natural curing for 24 hours, demold and then perform a constant temperature and pressure hydrothermal steam pressure reaction at 150℃ and 0.476MPa for 24 hours to foam and solidify, while simultaneously activating with steam heat.

[0101] Step 4: The carrier material prepared in step 3 is immersed in an aqueous solution containing 1% nitrifying bacteria and 1% guar gum for 60 minutes, then removed and sterilely vacuum dried at room temperature for 24 hours to obtain sludge biochar carrier material A with a particle size of 10 mm and a specific gravity of 0.8.

[0102] Manufacturing Example 2

[0103] The sludge biochar-sulfur-based mineral carrier material B in the second packing material is manufactured as follows:

[0104] Step 1: Mix 100 parts of sludge biochar, 10 parts of cement, 40 parts of sulfur-based mineral materials, 0.1 parts of aluminum powder, 8 parts of zeolite powder, and 1 part of basalt fiber evenly.

[0105] Step 2: Add 50 parts of a 2% hydroxymethyl cellulose aqueous solution, stir and mix, and pour into a mold to solidify and shape;

[0106] Step 3: After natural curing for 24 hours, demold and then perform a constant temperature and pressure hydrothermal steam pressure reaction at 150℃ and 0.476MPa for 24 hours to foam and solidify, while simultaneously activating with steam heat.

[0107] Step 4: The carrier material prepared in step 3 is immersed in an aqueous solution containing 1% sulfur autotrophic denitrifying bacteria and 1% guar gum for 60 minutes, then removed and sterilely vacuum dried at room temperature for 24 hours.

[0108] Step 5: The carrier material prepared in step 4 is immersed in an aqueous solution containing 1% nitrifying bacteria and 1% guar gum for 60 minutes, then removed and sterilely vacuum dried at room temperature for 24 hours to obtain sludge biochar-sulfur-based mineral carrier material B with a particle size of 10 mm and a specific gravity of 1.0.

[0109] Manufacturing Example 3

[0110] The sludge biochar-sulfur-based mineral carrier material C in the third packing material is manufactured as follows:

[0111] Step 1: Mix 100 parts of sludge biochar, 10 parts of cement, 40 parts of sulfur-based mineral materials, 0.05 parts of aluminum powder, 8 parts of zeolite powder, and 1 part of basalt fiber evenly.

[0112] Step 2: Add 50 parts of a 2% hydroxymethyl cellulose aqueous solution, stir and mix, and pour into a mold to solidify and shape;

[0113] Step 3: After natural curing for 24 hours, demold and then perform a constant temperature and pressure hydrothermal steam pressure reaction at 150℃ and 0.476MPa for 24 hours to foam and solidify, while simultaneously activating with steam heat.

[0114] Step 4: The carrier material prepared in step 3 is immersed in an aqueous solution containing 1% sulfur autotrophic denitrifying bacteria and 1% guar gum for 60 minutes, then removed and sterilely vacuum dried at room temperature for 24 hours to obtain sludge biochar-sulfur-based mineral carrier material C with a particle size of 10 mm and a specific gravity of 1.3.

[0115] Example 1

[0116] Sludge biochar carrier material A, sludge biochar-sulfur-based mineral carrier material B, and sludge biochar-sulfur-based mineral carrier material C should be acclimated for 1 week before use.

[0117] The influent of a wastewater treatment plant in Ma'anshan, after being treated by a cyclone grit chamber, is then processed by the process described in this invention:

[0118] The first treatment stage process is as follows: the upper and lower partitions have a pore size of 0.5cm and are filled with sludge biochar carrier material A with a filling rate of 20%. The aeration pipe is set above the lower partition for aeration. The dissolved oxygen is controlled at 3mg / L and the hydraulic retention time is 3h.

[0119] The second treatment section process: the upper and lower partitions have a pore size of 0.5cm and are filled with sludge biochar-sulfur-based mineral carrier material B with a filling rate of 40%. The aeration pipe is set above the lower partition for aeration, and the dissolved oxygen is controlled at 1mg / L with a hydraulic retention time of 4h.

[0120] The third treatment stage process: the upper and lower partitions have a pore size of 0.5cm, are filled with sludge biochar-sulfur-based mineral carrier material C, the filling rate is 80%, the dissolved oxygen is controlled at 0.3mg / L, and the hydraulic retention time is 2h;

[0121] The fourth treatment stage process: fill the sand filter section with natural quartz sand with a particle size of 0.5-1mm and retain it for 0.1 hours.

[0122] The total hydraulic residence time is 9 hours.

[0123] The effluent was tested for COD, ammonia nitrogen, TP, and TN. COD was determined using the dichromate method (GB11914) for the determination of chemical oxygen demand in water, ammonia nitrogen was determined using Nessler's reagent spectrophotometric method (HJ 535-2009) for the determination of ammonia nitrogen in water, TP was determined using the ammonium molybdate spectrophotometric method (GB 11893-89) for the determination of total phosphorus in water, and TN was determined using the alkaline potassium persulfate digestion ultraviolet spectrophotometric method (GB 11894-1989) for the determination of total nitrogen in water. The results are shown in Table 1.

[0124] Example 2

[0125] When the influent concentration increases, the system is impacted. The effluent concentration of the treatment process in Example 1 exceeds the standard. The system starts the reflux pump, and the water exits from the third treatment section and returns to the top of the tank. After mixing with the influent, it enters the first treatment section. The reflux ratio is controlled at 100%, and the influent volume is reduced by 20%.

[0126] The total hydraulic residence time is 9 hours.

[0127] The COD, ammonia nitrogen, TP and TN of the effluent were tested, and the results are shown in Table 2.

[0128] Comparative Example 1

[0129] The sludge biochar carrier material should be acclimated for one week before use.

[0130] The influent of a wastewater treatment plant in Ma'anshan, after being treated by a cyclone grit chamber with a screen, is then treated by the following comparative process:

[0131] The first stage of water treatment process: the upper and lower partitions have a pore size of 0.5cm and are filled with sludge biochar carrier material A with a filling rate of 20%. The aeration pipe is set above the lower partition for aeration. The dissolved oxygen is controlled at 3mg / L and the hydraulic retention time is 9h.

[0132] The second stage of water treatment process: sand filtration, filled with natural quartz sand with a particle size of 0.5-1mm, and a retention time of 0.1 hours.

[0133] The total hydraulic residence time is 9 hours.

[0134] The influent water quality was the same as in Example 1. The effluent water quality was tested for COD, ammonia nitrogen, TP and TN. The results are shown in Table 1.

[0135] Comparative Example 2

[0136] The sludge biochar carrier material should be acclimated for one week before use.

[0137] The influent of a wastewater treatment plant in Ma'anshan, after being treated by a cyclone grit chamber with a screen, is then treated by the following comparative process:

[0138] The first stage of water treatment process: the upper and lower partitions have a pore size of 0.5cm and are filled with sludge biochar-sulfur-based mineral carrier material B with a filling rate of 40%. The aeration pipe is set above the lower partition for aeration. The dissolved oxygen is controlled at 1mg / L and the hydraulic retention time is 9h.

[0139] The second stage of water treatment process: sand filtration, filled with natural quartz sand with a particle size of 0.5-1mm, and a retention time of 0.1 hours.

[0140] The total hydraulic residence time is 9 hours.

[0141] The influent water quality was the same as in Example 1. The effluent water quality was tested for COD, ammonia nitrogen, TP and TN. The results are shown in Table 1.

[0142] Comparative Example 3

[0143] The sludge biochar carrier material should be acclimated for one week before use.

[0144] The influent of a wastewater treatment plant in Ma'anshan, after being treated by a cyclone grit chamber with a screen, is then treated by the following comparative process:

[0145] The first stage of water treatment process: the upper and lower baffles have a pore size of 0.5cm and are filled with sludge biochar-sulfur-based mineral carrier material C with a filling rate of 80%. The dissolved oxygen is controlled at 0.3mg / L and the hydraulic retention time is 9h.

[0146] The second stage of water treatment process: sand filtration, filled with natural quartz sand with a particle size of 0.5-1mm, and a retention time of 0.1 hours.

[0147] The total hydraulic residence time is 9 hours.

[0148] The influent water quality was the same as in Example 1. The effluent water quality was tested for COD, ammonia nitrogen, TP and TN. The results are shown in Table 1.

[0149] Comparative Example 4

[0150] The sludge biochar carrier material should be acclimated for one week before use.

[0151] The influent of a wastewater treatment plant in Ma'anshan, after being treated by a cyclone grit chamber with a screen, is then treated by the following comparative process:

[0152] The first stage of water treatment process: the upper and lower partitions have a pore size of 0.5cm and are filled with sludge biochar carrier material A with a filling rate of 20%. The aeration pipe is set above the lower partition for aeration. The dissolved oxygen is controlled at 3mg / L and the hydraulic retention time is 4h.

[0153] The second stage of water treatment process: the upper and lower partitions have a pore size of 0.5cm and are filled with sludge biochar-sulfur-based mineral carrier material B with a filling rate of 40%. The aeration pipe is set above the lower partition for aeration, and the dissolved oxygen is controlled at 1mg / L with a hydraulic retention time of 5h.

[0154] The third stage of water treatment process: sand filtration, filled with natural quartz sand with a particle size of 0.5-1mm, and a retention time of 0.1 hours.

[0155] The total hydraulic residence time is 9 hours.

[0156] The influent water quality was the same as in Example 1. The effluent water quality was tested for COD, ammonia nitrogen, TP and TN. The results are shown in Table 1.

[0157] Comparative Example 5

[0158] The sludge biochar carrier material should be acclimated for one week before use.

[0159] The influent of a wastewater treatment plant in Ma'anshan, after being treated by a cyclone grit chamber with a screen, is then treated by the following comparative process:

[0160] The first stage of water treatment process: the upper and lower partitions have a pore size of 0.5cm and are filled with sludge biochar carrier material A with a filling rate of 20%. The aeration pipe is set above the lower partition for aeration. The dissolved oxygen is controlled at 3mg / L and the hydraulic retention time is 6h.

[0161] The second stage of water treatment process: the upper and lower partitions have a pore size of 0.5cm and are filled with sludge biochar-sulfur-based mineral carrier material C with a filling rate of 80%. The dissolved oxygen is controlled at 0.3mg / L and the hydraulic retention time is 3h.

[0162] The third stage of water treatment process: sand filtration, filled with natural quartz sand with a particle size of 0.5-1mm, and a retention time of 0.1 hours.

[0163] The total hydraulic residence time is 9 hours.

[0164] The influent water quality was the same as in Example 1. The effluent water quality was tested for COD, ammonia nitrogen, TP and TN. The results are shown in Table 1.

[0165] Comparative Example 6

[0166] The sludge biochar carrier material should be acclimated for one week before use.

[0167] The influent of a wastewater treatment plant in Ma'anshan, after being treated by a cyclone grit chamber with a screen, is then treated by the following comparative process:

[0168] The first stage of water treatment process: the upper and lower partitions have a pore size of 0.5cm and are filled with sludge biochar-sulfur-based mineral carrier material B with a filling rate of 40%. The aeration pipe is set above the lower partition for aeration. The dissolved oxygen is controlled at 1mg / L and the hydraulic retention time is 6h.

[0169] The second stage of water treatment process: the upper and lower partitions have a pore size of 0.5cm and are filled with sludge biochar-sulfur-based mineral carrier material C with a filling rate of 80%. The dissolved oxygen is controlled at 0.3mg / L and the hydraulic retention time is 3h.

[0170] The third stage of water treatment process: sand filtration, filled with natural quartz sand with a particle size of 0.5-1mm, and a retention time of 0.1 hours.

[0171] The total hydraulic residence time is 9 hours.

[0172] The influent water quality was the same as in Example 1. The effluent water quality was tested for COD, ammonia nitrogen, TP and TN. The results are shown in Table 1.

[0173]

[0174] As shown in Table 1, the wastewater treatment process based on sludge biochar carrier material in this embodiment of the invention consistently produces effluent that is superior to the Class A standard of the national urban wastewater discharge standard (GB18918-2002), while the effluent indicators of Comparative Examples 1-6 either fail to meet one or more discharge standards. When the influent concentration is high and the system is subjected to shock, the backflow is activated to reduce the influent, as shown in Table 2, and the system can then operate stably and meet the standards.

[0175]

[0176] In summary, compared with existing technologies, this invention employs a highly efficient water treatment process and miniaturized water treatment equipment, enabling efficient treatment of low C / N wastewater. It is energy-saving, environmentally friendly, and requires minimal floor space for convenient application. This invention boasts advantages such as simple process, convenient operation, and high treatment efficiency. It utilizes a three-stage biofilm treatment, achieving aerobic treatment, simultaneous nitrification, and sulfur autotrophic denitrification through different packing materials in each stage. This results in excellent treatment of low C / N wastewater without the need for carbon source addition. Aerobic treatment and simultaneous nitrification / denitrification are achieved within the same equipment. Furthermore, the equipment has a compact structure, low manufacturing cost, high integration, and a small floor space, making it suitable for large-scale production and application, especially for small-scale urban sewage, rural sewage, and black and odorous water environment treatment.

[0177] Many specific details have been set forth in the foregoing description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed above.

Claims

1. A wastewater treatment process based on sludge biochar carrier, characterized in that: The system is divided into a first treatment section, a second treatment section, a third treatment section, and a sand filtration section, which are integrated into a tank from top to bottom. The first treatment section is filled with a first packing material for aerobic aeration of wastewater; the second treatment section is filled with a second packing material for simultaneous nitrification and denitrification of wastewater through aeration; and the third treatment section is filled with a third packing material for treating total nitrogen (TN) in wastewater. Both the first and second treatment sections are equipped with aeration components. The tops of the first, second, third, and sand filtration sections are equipped with baffles with water passage holes. The tank has an inlet at the top and an outlet at the bottom. Wastewater flows sequentially through the first, second, third, and sand filtration sections, with a total retention time controlled at 6-12 hours. The first packing material inside the first treatment section is a sludge biochar carrier material, and the surface of the sludge biochar carrier is covered with an aerobic biological layer: an aerobic microbial layer is wrapped on the outside of the carrier material by a bio-adhesive, and the aerobic microbial layer is impregnated with aerobic microorganisms. The sludge biochar carrier material includes sludge-based biochar, binders, and functional materials. The binders include organic and inorganic binders, and the weight proportions of each component are as follows: Sludge-based biochar: 100 parts; Organic binder: 0.1-10 parts; Inorganic binder: 1-20 parts; Functional materials: 0.1-10 parts; Water: 20-100 parts; The functional materials include foaming agents, adsorbents, and reinforcing fibers, which are mixed in a weight ratio of 1:(10-100):(5-50). The above components are mixed and solidified to form a sludge biochar carrier material; The second packing material inside the second treatment section uses sludge biocarbon-sulfur-based mineral carrier material as the core. The surface of the sludge biocarbon-sulfur-based mineral carrier material is sequentially coated with a sulfur autotrophic denitrifying bacteria layer and an aerobic microbial layer. The aerobic microbial layer covers the outside of the sulfur autotrophic denitrifying bacteria layer. Sludge biochar-sulfur-based mineral carrier materials include sludge-based biochar, binders, sulfur-based mineral materials, and functional materials. The binders include organic binders and inorganic binders. The above components are mixed and solidified to form sludge biochar-sulfur-based mineral carrier material; The third packing material inside the third treatment section uses sludge biocarbon-sulfur-based mineral carrier material as the core, and a sulfur autotrophic denitrifying bacteria layer is coated on the surface of the sludge biocarbon-sulfur-based mineral carrier material.

2. The wastewater treatment process based on sludge biochar carrier according to claim 1, characterized in that: The sludge biochar carrier material has a particle size of 1-2 cm and a specific gravity of 0.8-1 g / cm³. 3 The first packing material has a filling rate of 20-30% in the first treatment section, and dissolved oxygen is controlled at 2-3 mg / L; the wastewater retention time in the first treatment section is controlled at 2-4 hours.

3. The wastewater treatment process based on sludge biochar carrier according to claim 2, characterized in that: The sludge-based biocarbon-sulfur-based mineral carrier material has a particle size of 1-2 cm and a specific gravity of 1-1.2 g / cm³. 3 The second packing material has a filling rate of 30-40% in the second treatment section, dissolved oxygen is controlled at 1-2 mg / L, and the wastewater retention time in the second treatment section is controlled at 3-5 hours. The weight proportions of each component in the sludge biochar-sulfur-based mineral carrier material are as follows: Sludge-based biochar: 100 parts; Organic binder: 0.1-10 parts; Inorganic binder: 1-20 parts; Sulfur-based mineral materials: 10-50 parts; Functional materials: 0.1-10 parts; Water: 20-100 servings.

4. The wastewater treatment process based on sludge biochar carrier according to claim 3, characterized in that: The third packing material has a filling rate of 60-80% in the third treatment section, dissolved oxygen is controlled at 0.2-0.5 mg / L, and the wastewater retention time in the third treatment section is controlled at 1-3 hours.

5. The wastewater treatment process based on sludge biochar carrier according to claim 4, characterized in that: The interior of the sand filter section is filled with quartz sand with a particle size of 0.5-1mm; the residence time of sewage in the sand filter section is controlled at 0.01-0.5 hours.

6. The wastewater treatment process based on sludge biochar carrier according to claim 1, characterized in that: When the effluent concentration increases after the wastewater has passed through the first treatment section, the second treatment section, the third treatment section, and the sand filtration section, the reflux system is activated. The reflux system includes a reflux pipe and a reflux pump. The inlet end of the reflux pipe is connected to the outlet end of the third treatment section, and the outlet end of the reflux pipe is connected to the inlet of the first treatment section. The reflux pump is installed on the reflux pipe.

7. The wastewater treatment process based on sludge biochar carrier according to claim 1, characterized in that: The diameter of the water passage holes on the partition is 0.5-1cm.

8. The wastewater treatment process based on sludge biochar carrier according to claim 6, characterized in that: The aeration component is an aeration disc, which is respectively installed at the bottom of the first treatment section and the second treatment section. The aeration disc is connected to the blower through a duct.

9. The wastewater treatment process based on sludge biochar carrier according to claim 8, characterized in that: The air duct is equipped with an air volume control valve, and the bottom of the housing is equipped with a water outlet control valve.

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