A bamboo charcoal suspended filler ball for sewage treatment and a preparation method and application thereof

Abstract

The present application relates to the technical field of suspended filler ball for sewage treatment, in particular to a kind of bamboo charcoal suspended filler ball for sewage treatment and preparation method and application.It includes spherical shell and filler arranged in the interior of spherical shell;The spherical shell is prepared from the following materials:495-498 parts by weight of high-density polyethylene, 1-3 parts by weight of silicon dioxide, 1-2 parts by weight of zinc oxide;The internal filler is modified bamboo charcoal filler.The modified bamboo charcoal filler filled in the bamboo charcoal suspended filler ball prepared by the present application has good adsorption performance, biodegradability and certain electrical conductivity, which can provide better biological affinity, shorten the biofilm formation time by more than 40%, increase the biofilm formation amount by 70%-80%, thereby enrich and fix a large number of water treatment microorganisms in sewage, and realize stable operation of the sewage treatment system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of suspended filler balls for sewage treatment, and particularly relates to a bamboo charcoal suspended filler ball for sewage treatment, a preparation method and application thereof. BACKGROUND

[0002] The moving bed biofilm reactor (MBBR) is a new and efficient sewage treatment technology, which is widely used due to high treatment efficiency, good denitrification effect, simple operation and maintenance, and the like. The principle is to add suspended filler with large specific surface area to water to provide a place for the microorganisms suspended in the water to attach and grow, and eventually form a mature biofilm that completely wraps the filler. The microorganisms on the membrane decompose and utilize the pollutants, thereby achieving sewage treatment.

[0003] The suspended filler is the core component of the MBBR, and the performance of the filler will directly affect the sewage treatment efficiency. Currently, the main types of commonly used suspended fillers include fluidized bed fillers, suspended ball fillers, and combined fillers, etc. However, they are mainly made of a single high polymer material, and have a low specific surface area, which leads to low filler strength and slow biofilm formation, and seriously affects the treatment efficiency.

[0004] China is the largest country of bamboo resources in the world, and the bamboo resources and bamboo output are the largest in the world. Bamboo charcoal is a porous material prepared by pyrolysis of bamboo, and is a low-cost environmental protection material with developed pores, hard texture, and strong adsorption capacity. Bamboo charcoal is often used as a water purifying agent in the field of sewage treatment, which can adsorb harmful chemical substances in water and absorb odors and harmful gases in water. Although bamboo charcoal has excellent functionality, the surface pores and specific surface area of unmodified bamboo charcoal are limited, and the exchange rate is slow, which is not conducive to the attachment and growth of microorganisms. Modified bamboo charcoal can further improve the adsorption capacity and adsorption regeneration capacity, and strengthen the attachment of microorganisms. Selecting appropriate modified bamboo charcoal can prepare a new type of MBBR filler to improve the performance of traditional suspended fillers. SUMMARY

[0005] In view of the deficiencies in the prior art, the present application provides a bamboo charcoal suspended filler ball for sewage treatment with large specific surface area, which is conducive to the attachment and growth of microorganisms and has a wide range of applications, as well as a preparation method and application thereof.

[0006] The technical scheme adopted by the present application to achieve the above-mentioned purpose is as follows: a bamboo charcoal suspended filler ball for sewage treatment, comprising a spherical shell and a filler arranged in the spherical shell.

[0007] The spherical shell is prepared from the following materials: 495-498 parts by weight of high-density polyethylene, 1-3 parts by weight of silicon dioxide, and 1-2 parts by weight of zinc oxide.

[0008] The internal filler is modified bamboo charcoal filler.

[0009] Further, the overall density of the filler ball is 0.96-1.06 g / cm 3 , and the specific surface area of the spherical shell is 480 m 2 / m 3 .

[0010] Further, the density of the spherical shell is 0.962-0.976 g / cm 3 , and the wet density of the modified bamboo charcoal filler is 1.15 g / cm 3 .

[0011] Further, the diameter of the spherical shell is 3-4 cm, and the weight is 5-8 g.

[0012] The preparation method of the bamboo charcoal suspended filler ball for sewage treatment comprises the following steps:

[0013] (1) preparing a suspended filler ball shell:

[0014] Take high-density polyethylene, silicon dioxide and zinc oxide, and mix them together, form a mixed powder after granulation and crushing, and then use a double-screw extruder to shape the mixed powder, extrude through a hemispherical mold after heating and plasticizing, and obtain a hemispherical filler ball shell;

[0015] (2) preparing a bamboo charcoal filler:

[0016] Select the middle part of the bamboo pole and divide it into segmental bamboo poles, and then put the segmental bamboo poles into a high-temperature tube furnace after natural drying, and obtain bamboo charcoal after pyrolysis and cooling;

[0017] (3) modification of the bamboo charcoal filler:

[0018] Make the bamboo charcoal of (2) into a sheet, immerse it in a 35% potassium hydroxide solution for 48 hours, then dry it in an oven, put the dried bamboo charcoal particles into a muffle furnace, adjust the nitrogen flow to 200 mL / min, and activate at high temperature to complete the modification. After the modification is completed, wash repeatedly with deionized water until it is neutral, dry again in an oven, and obtain the modified bamboo charcoal filler;

[0019] (4) preparing a bamboo charcoal suspended filler ball:

[0020] Put a certain weight of the modified bamboo charcoal filler prepared in (3) into the hemispherical filler ball shell prepared in (1), and use two identical hemispherical filler ball shells to encapsulate the modified bamboo charcoal filler by screw clamping.

[0021] Further,

[0022] The length of the segmental bamboo pole in the (2) is 3-5 cm, the tube furnace temperature is 350 DEG C, and the pyrolysis time is 30 min.

[0023] Further,

[0024] The bamboo charcoal in the (3) is made into a sheet with a width of 0.5-1 cm, the oven temperature is 105 DEG C, and the activation condition is 700 DEG C for 2 h.

[0025] Further, the diameter of the spherical shell is 3-4 cm, the weight is 5-8 g, and the weight of the internal modified bamboo charcoal filler is 0.2-5 g.

[0026] The bamboo charcoal suspended filler ball is used for treating municipal wastewater or mariculture wastewater.

[0027] The modified bamboo charcoal filler filled in the bamboo charcoal suspended filler ball has good adsorption performance, biodegradation capacity and certain conductivity, can provide better biological affinity, shorten the biofilm formation time by more than 40%, increase the biofilm formation amount by 70%-80%, thereby enriches and fixes a large amount of water treatment microorganisms in the wastewater, and realizes stable operation of the wastewater treatment system. DETAILED DESCRIPTION

[0028] The application will be further described in detail below in combination with specific embodiments:

[0029] Embodiment 1:

[0030] A bamboo charcoal suspended filler ball for wastewater treatment comprises a spherical shell and a filler arranged in the spherical shell, wherein the spherical shell is prepared from 495-498 parts by weight of high-density polyethylene, 1-3 parts by weight of silicon dioxide and 1-2 parts by weight of zinc oxide; and the filler is modified bamboo charcoal filler, and the specific gravity of the suspended filler ball is adjusted. The specific surface area and total pore volume of the modified bamboo charcoal filler are greatly improved, which is beneficial to the growth and adhesion of microorganisms, and thus the pollutant removal capacity is improved.

[0031] The high-density polyethylene (HDPE) is a white powder and particulate product, is non-toxic and odorless, has a density of 0.95 g / cm 3 , a softening point of 125-135 DEG C, high crystallinity, high heat resistance and cold resistance, strong chemical stability and high mechanical strength.

[0032] The silicon dioxide is an environmentally friendly white powder product, is chemically stable, has a density of 2.2 g / cm 3 , small particle size, many micropores, large specific surface area and strong adsorption.

[0033] The zinc oxide is a white powder product, has fine natural particle size, and has a density of 5.6 g / cm3 The metal oxide has certain conductivity, and the density and electrical property thereof are moderate, and the metal oxide can be used as a white pigment.

[0034] The bamboo charcoal filler is prepared from natural growth and old Phyllostachys edulis, the Phyllostachys edulis is widely distributed and has strong growth and reproduction capacity, and has excellent resource utilization value.

[0035] The preparation method of the bamboo charcoal suspended filler ball for sewage treatment comprises the following steps:

[0036] (1) 498 parts of high-density polyethylene, 1 part of silicon dioxide and 1 part of zinc oxide are weighed according to a preset weight ratio, mixed together, granulated and crushed to form a mixed powder, and the obtained mixed powder is molded by a double-screw extruder, extruded through a semi-spherical mold after being heated and plasticized, and a semi-spherical filler ball shell is obtained;

[0037] (2) The bamboo charcoal filler is prepared: the middle part of the bamboo pole is selected, segmented into 3cm long bamboo poles, and after natural drying, the bamboo segments are placed in a high-temperature tube furnace, pyrolyzed at 350℃ for 30min, and cooled to obtain the bamboo charcoal;

[0038] (3) Modification of the bamboo charcoal filler: the bamboo charcoal filler is made into a 50mm wide sheet, immersed in a 35% potassium hydroxide solution for 48h, and then dried in an oven at 105℃. The dried bamboo charcoal particles are placed in a muffle furnace, the nitrogen flow is adjusted to 200mL / min, and the high-temperature activation is carried out at 700℃ for 2h to complete the modification. After the modification is completed, the modified bamboo charcoal is repeatedly washed with deionized water until it is neutral, and then dried in an oven at 105℃. After drying, it is stored for use;

[0039] (4) Preparation of the bamboo charcoal suspended filler ball: 0.4g of the modified bamboo charcoal filler prepared in step (3) is loaded into the semi-spherical filler ball shell prepared in step (1), and two identical semi-spherical filler ball shells are used to clamp the modified bamboo charcoal filler inside by using threads. The spherical design can ensure that it does not form a ball and block during use, and has good fluidization performance.

[0040] The suspended filler ball shell prepared in this embodiment has a weight of 6g, and the overall density of the suspended filler ball is 0.973g / cm 3 , which is close to the density of water, and can replace the traditional high-density polyethylene filler for treating municipal sewage with a density close to water.

[0041] The simulated municipal sewage is used as the influent, and the suspended filler ball prepared in the embodiment is used for treatment. The main pollutants in the influent are controlled to be about 130 mg / L of COD concentration and about 20 mg / L of NH3-N concentration, the suspended filler ball prepared in the embodiment 1 is filled at a filling rate of 25%, and the hydraulic retention time is controlled to be 6 h. The continuous influent is used for biofilm formation, and the surface of the modified bamboo charcoal filler is covered with mature biofilm in 12 days. After stable operation, the average COD concentration of the effluent is 24.6 mg / L, the average removal rate of COD is 81%, the average NH3-N concentration of the effluent is 4.2 mg / L, and the average removal rate of NH3-N is 79%, and the treatment effect is good.

[0042] The raw material of the external spherical shell of the bamboo charcoal suspended filler ball prepared in the embodiment has good toughness, so that the heating and plasticizing process is not easy to expand and crack. The external shell of the suspended filler ball is mainly made of high-density polyethylene, and silica and zinc oxide are added to reduce the preparation cost and improve the overall strength of the carrier. The structure damage rate of the external shell is not more than 3%, the environmental stress cracking resistance failure time is ≥2400 h, and the expected service life is more than 10 years. The modified bamboo charcoal filler filled in the bamboo charcoal suspended filler ball prepared in the embodiment has developed pores, high mechanical strength and good adsorption. After modification by potassium hydroxide, the specific surface area is greatly increased, and the contact area between microorganisms and pollutants and the filler is increased. The modified bamboo charcoal filler has high mechanical strength and can be regenerated repeatedly, which is conducive to the automatic update of the surface biofilm under the action of water flow.

[0043] Embodiment 2

[0044] The preparation method of the bamboo charcoal suspended filler ball for sewage treatment comprises the following steps:

[0045] (1) The high-density polyethylene 495 parts, the silica 3 parts and the zinc oxide 2 parts are weighed according to the preset weight parts, mixed together, granulated and crushed to form a mixed powder, and the obtained mixed powder is formed by a double-screw extruder, heated and plasticized, and then extruded through a hemispherical mold to obtain a hemispherical filler ball shell;

[0046] (2) The bamboo charcoal filler is prepared: the middle part of the bamboo is selected and cut into 2 cm long bamboo segments, and after natural drying, the bamboo segments are placed in a high-temperature tube furnace, pyrolyzed at 350℃ for 30 min, and cooled to obtain bamboo charcoal;

[0047] (3) Modification of the bamboo charcoal filler: the bamboo charcoal filler is made into a sheet with a width of 1 cm, soaked in a 35% potassium hydroxide solution for 48 h, and then dried in an oven at 105℃. The dried bamboo charcoal particles are placed in a muffle furnace, the nitrogen flow is adjusted to 200 mL / min, and the modification is completed at 700℃ for 2 h. After the modification is completed, the particles are repeatedly washed with deionized water until they are neutral, and then dried in an oven at 105℃. The dried particles are stored for use;

[0048] (4) Preparation of bamboo charcoal suspended filler ball: 4g of modified bamboo charcoal filler prepared in step (3) is loaded into the hemispherical filler ball shell prepared in step (1), and the modified bamboo charcoal filler is encapsulated in the two identical hemispherical filler ball shells by screw clamping.

[0049] The suspended filler ball shell prepared in the embodiment has a weight of 5g, and the overall density of the suspended filler ball is 1.051g / cm3, which is close to the density of seawater, and can be used for treating seawater aquaculture wastewater with high density.

[0050] The bamboo charcoal suspended filler ball prepared in the present application has silica added to the outer spherical shell, which is an excellent hydrophilic material, reducing the contact angle of the finally prepared filler ball shell by about 20% and enhancing the hydrophilicity of the filler. Zinc oxide is added to the filler of the outer spherical shell of the bamboo charcoal suspended filler ball prepared in the present application, which can provide a weak positive charge to the suspended filler, which is beneficial to adsorb water treatment microorganisms with negative charge in sewage, such as nitrifying bacteria, denitrifying bacteria and phosphorus-removing bacteria. As an effective white pigment, zinc oxide does not turn black when it meets hydrogen sulfide gas, so that the finally prepared suspended filler ball shell is white, which is easier to observe the biofilm formation with naked eye.

[0051] The bamboo charcoal suspended filler ball prepared in the present application has high surface roughness and good hydrophilicity, which can impact atmospheric bubbles and cut them into small bubbles with larger specific surface area under the action of aeration, improve the oxygen mass transfer speed, and reduce the aeration amount by more than 10%, thereby reducing energy consumption.

[0052] The above embodiments are only for the purpose of illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made in accordance with the essence of the present application should be covered within the protection scope of the present application.

Claims

1. A method for preparing bamboo charcoal suspended packing balls for wastewater treatment, characterized in that, Preparation methods include: (1) Preparation of suspended packing spherical shells: Take 495-498 parts by weight of high-density polyethylene, 1-3 parts by weight of silicon dioxide and 1-2 parts by weight of zinc oxide, mix them together, granulate and crush them to form a mixed powder, shape the mixed powder with a twin-screw extruder, heat and plasticize it, and then extrude it through a hemispherical mold to obtain a hemispherical filler ball shell. (2) Preparation of bamboo charcoal filler: Select the middle part of the bamboo pole and cut it into sections of 3-5cm in length. After natural drying, place the bamboo sections neatly into a high-temperature tube furnace for pyrolysis and cooling to obtain bamboo charcoal. (3) Modification of bamboo charcoal filler: The bamboo charcoal from (2) was made into sheets with a width of 0.5-1cm, soaked in 35% potassium hydroxide solution for 48h, and then dried in an oven at 105℃. The dried bamboo charcoal particles were placed in a muffle furnace, and the nitrogen flow rate was adjusted to 200mL / min. The temperature was 700℃ for 2h to complete the modification. After the modification was completed, the particles were repeatedly rinsed with deionized water until they were about neutral. They were then dried in an oven again to obtain the modified bamboo charcoal filler. (4) Preparation of bamboo charcoal suspension filler balls: Take a certain weight of the modified bamboo charcoal filler prepared in (3) and put it into the hemispherical filler shell prepared in (1). Use two identical hemispherical filler shells to be threaded together to encapsulate the modified bamboo charcoal filler inside. The bamboo charcoal suspension filler ball includes a spherical shell and filler material disposed inside the spherical shell; The overall density of the packing balls is 0.96–1.06 g / cm³. 3 The specific surface area of ​​the spherical shell is 480 m². 2 / m 3 ; The density of the spherical shell is 0.962~0.976 g / cm³. 3 The modified bamboo charcoal filler has a wet density of 1.15 g / cm³. 3 .

2. The method for preparing bamboo charcoal suspended packing balls for wastewater treatment according to claim 1, characterized in that: In (2), the temperature of the tubular furnace is 350 ℃ and the pyrolysis time is 30 min.

3. The method for preparing bamboo charcoal suspended packing balls for wastewater treatment according to claim 1, characterized in that: The spherical outer shell has a diameter of 3-4cm and a weight of 5-8g, while the internal modified bamboo charcoal filler weighs 0.2-5g.

4. The application of bamboo charcoal suspended packing balls for sewage treatment, characterized in that: [the following is a description of the process:] The bamboo charcoal suspended packing balls are prepared by the method described in any one of claims 1-3, and are used for the treatment of municipal wastewater or marine aquaculture wastewater.