CN114804360A

CN114804360A - Modified expanded perlite particles and preparation method and application thereof

Info

Publication number: CN114804360A
Application number: CN202210575248.5A
Authority: CN
Inventors: 万丽; 张淞萱
Original assignee: Hunan Wufang Environmental Science And Technology Research Institute Co ltd
Current assignee: Hunan Sanyou Environmental Protection Technology Co ltd
Priority date: 2022-05-24
Filing date: 2022-05-24
Publication date: 2022-07-29
Anticipated expiration: 2042-05-24
Also published as: WO2023227143A1; CN114804360B

Abstract

The invention provides a medium-modified expanded perlite particle and a preparation method and application thereof, wherein the preparation method comprises the following steps: s1: preparing pyrite powder slurry with the solid content of 1-15%, wherein the particle size of the pyrite powder is less than 10 microns; s2: placing expanded perlite particles into a negative pressure container with the gauge pressure of-0.1 to-0.05 Mpa, and injecting the pyrite powder slurry into the negative pressure container; the particle size of the expanded perlite particles is 0.5-4mm, and the pore diameter of the surface of the expanded perlite particles is larger than that of the pyrite powder; s3: and adding water into the negative pressure container, standing for 5-120 min, and collecting sinking particles, wherein the sinking particles are the modified expanded perlite particles. The invention provides a modified expanded perlite particle carrier, a method for preparing the carrier and sewage treatment application of the carrier in a specific reactor, and the carrier has good sewage treatment effect and strong practicability and is worthy of popularization.

Description

Modified expanded perlite particles and preparation method and application thereof

Technical Field

The invention relates to the field of preparation of expanded perlite particles and the field of sewage treatment, in particular to modified expanded perlite particles and a preparation method and application thereof.

Background

With the increasing prominence of environmental capacity and water environment problems, the requirement for environmental protection is continuously increased. The existing sewage treatment plants are all faced with the requirement of upgrading the effluent quality from the first grade B standard to the first grade A standard or even higher. The currently common biological sewage treatment methods are divided into two categories: (1) one is an activated sludge method, which is characterized in that the microorganism for treating sewage is in a suspension state in a bioreactor; (2) the second type is a sewage treatment microorganism attachment growth method, wherein microorganisms are attached to the surface of a carrier in a certain form for immobilization growth. The two types of sewage biological treatment methods have a history of over one hundred years from the invention to the present, and great guarantee is brought to human water consumption through a series of improvements and perfections, but the two types of methods are limited by the technology and are developed into bottlenecks at present. The limiting factors of the activated sludge process include: (1) limited by the suspension growth characteristic, imperfect microbial diversity and influence on the deep treatment effect; (2) limited by the parameters of the sewage treatment process, and the growth cycle of part of key microorganisms is limited; (3) is limited by the change of the water quality of the inlet water and the supply fluctuation of nutrient factors for the growth of microorganisms, and influences the biological activity and the actual treatment effect. The limited factors of the sewage treatment microorganism attachment growth rule include particle recycling energy consumption, carrier loading effect on an electron donor and application devices of particles in sewage treatment.

For example, the application of the inorganic composite powder carrier disclosed in publication No. CN 110627226A and the composite powder carrier used in the application of the inorganic composite powder carrier in the enhanced biological denitrification of urban sewage treatment utilize the larger surface energy of the expanded perlite particles and adopt a wet filterability stirring mode to tightly adsorb the nano-scale inorganic alternative carbon source on the diatomite, the attapulgite, the perlite or the zeolite expanded perlite particles.

The expanded perlite particles are easy to prepare and good in loading effect, but still have the following defects: firstly, the particle size difference between a carrier and an alternative carbon source is small, the equivalent particle size of the carrier is 10 microns, and the equivalent particle size of the alternative carbon source powder is nano-scale, so that the adsorption effect of the alternative carbon source powder is not compact enough, and the alternative carbon source powder is easy to desorb during later use; secondly, a wet filtering and stirring mode is adopted, carbon source powder is replaced on a carrier and is unevenly distributed, the load capacity of expanded perlite particles in unit mass is small, the subsequent microorganisms are not favorably attached and grown, microbial colonies (including denitrifying bacteria, phosphorus accumulating bacteria and the like) are not favorably formed, and the subsequent expanded perlite particles loaded with pyrite powder are large in adding amount, high in adding frequency and high in cost loss; finally, in the aspect of carrier sewage treatment application, the organic composite powder carrier is put into a sewage treatment biochemical pool and then stirred, on one hand, aged sludge particles and fresh sludge particles cannot be separated by mixing mechanical stirring, and on the other hand, mechanical stirring is not suitable for carriers with larger particle sizes, so that carrier structures with larger particle sizes are easy to break.

In order to solve the problems, the invention uses a vacuum loading method to load the pyrite powder on the expanded perlite particles, and the expanded perlite is a finished product after the perlite is roasted and has the characteristics of low volume weight, high porosity, stable chemical performance, no biological toxicity and the like. The expanded perlite is used as a filler for sewage treatment, has a highly porous structure and uniform particle size distribution, and can provide attachment points for the growth of microorganisms. However, the expanded perlite has the problems of low mechanical strength, easy breakage, long biofilm formation period and the like.

Meanwhile, the invention utilizes a sewage treatment reaction device disclosed in the publication number CN113860487A, namely a sewage treatment device named as an aerobic granular sludge culture device, and utilizes an activated sludge method and a microorganism attachment growth method to construct a composite bioreactor which comprises suspended growing microorganisms and biological carriers, so that a microorganism system with symbiosis of 'double sludge' (namely activated sludge and sludge containing the biological carriers) is formed in the composite bioreactor, the microorganism growth amount of a biological treatment unit is increased, and the nitrogen and phosphorus removal efficiency in the sewage treatment process is improved.

Disclosure of Invention

The invention provides modified expanded perlite particles and a preparation method and application thereof, and aims to solve the problems of poor carrier loading effect, poor microorganism enrichment environment in a sewage treatment process, low sewage treatment efficiency, high energy consumption and the like in the prior art.

In order to achieve the above object, the present invention provides a method for preparing modified expanded perlite particles, which is characterized by comprising the steps of:

s1: preparing pyrite powder slurry with solid content of 1-15%, wherein the particle size of the pyrite powder is less than 10 microns;

s2: placing expanded perlite particles into a negative pressure container with the gauge pressure of-0.1 to-0.05 Mpa, and injecting the pyrite powder slurry into the negative pressure container;

the particle size of the expanded perlite particles is 0.5-4mm, and the surface pore diameter of the expanded perlite particles is larger than that of the pyrite powder;

s3: and adding water into the negative pressure container, standing for 5-120 min, and collecting settled particles, wherein the settled particles are the modified expanded perlite particles.

Furthermore, the pyrite powder is fine pyrite after being crushed and screened, and the sulfur content in the fine pyrite is more than 30%.

The mass ratio of the expanded perlite particles to the pyrite powder is 1-10: 1.

Further, the step S3 further includes a screening process and a drying process, where the screening process includes: enabling the settled particles to pass through a standard sieve of 20-40 meshes, and taking oversize products; the drying process comprises: and drying the oversize product, wherein the drying temperature is 105-150 ℃, and the drying time is 2-5 h.

The invention also provides modified expanded perlite particles prepared according to any one of the above preparation methods.

The invention also provides application of the modified expanded perlite particles prepared by any one of the preparation methods in sewage treatment.

Further, the application of the modified expanded perlite particles in sewage comprises the following steps:

s1: adding the modified expanded perlite particles into a reactor, wherein the adding volume of the modified expanded perlite particles accounts for 10-50% of the volume of the reactor;

s2: inoculating sludge with the concentration of 3000mg/L-6000mg/L into the reactor;

s3: adding sewage to the bottom of the reactor in a pulse mode, wherein the sewage adding direction is from bottom to top, and the pulse water inlet frequency is as follows: feeding water for 5-10 s every 20-60 s;

s4: collecting liquid overflowing from the upper part of the reactor;

s5: and after the modified expanded perlite particles in the reactor are subjected to biofilm formation, controlling the light material in the reactor to enter a sludge storage tank along with the water flow from bottom to top.

Further, in the step S4, the collecting the liquid overflowing from the upper portion of the reactor includes: part of liquid overflowing from the upper part of the reactor flows back to the bottom of the reactor in a mode of pulse water feeding from bottom to top; and conveying the rest of liquid overflowing from the upper part of the reactor to a liquid outlet device.

Further, the method also comprises the following steps: oxygen was supplied to the bottom of the reactor.

Further, in the process of supplying oxygen to the bottom of the reactor, detecting the dissolved oxygen in the reactor by a DO online monitoring system: the DO online monitoring system comprises a first probe and a second probe;

wherein the vertical distance between the first probe and the second probe is 0.4-0.6 m, the first probe is positioned below the second probe, and the vertical distance between the first probe and the bottom of the reactor is 0.1 m;

the range of the first probe is controlled to be 3-5mg/L, and the range of the second probe is controlled to be less than 0.5 mg/L.

The beneficial effects of the invention comprise at least the following three points:

(1) the expanded perlite particles used in the invention are expanded perlite particles which have a highly abundant pore structure and can provide sites for the attachment of pyrite powder and microorganisms, so that the adjustable and controllable load of the pyrite powder is realized; meanwhile, compared with the traditional gravity ballast and wet stirring, the invention uses the vacuum ballast method, so that the pyrite powder enters the internal framework of the expanded perlite under the condition of negative pressure, and because of the huge particle size difference between the expanded perlite particles and the pyrite powder, the expanded perlite particles and the pyrite powder are tightly and uniformly combined in the sewage treatment process and are not easy to desorb.

(2) In the invention, the pyrite powder is loaded in the expanded perlite particles, on one hand, because the pyrite powder has rich attachment sites, a large amount of sulfur autotrophic denitrifying bacteria are induced and formed in a sewage treatment system, and nitrogen in the system is removed through autotrophic denitrification, so that the advantage is obvious when the water quality with low carbon-nitrogen ratio is treated; on the other hand, an aerobic/anoxic microenvironment is formed after the modified expanded perlite is subjected to biofilm formation, so that functional colonies are promoted to form an internal carbon source, and favorable conditions are created for synchronous nitrification and denitrification.

(3) According to the invention, the sewage treatment mode by using the modified expanded perlite particles has strong adaptability with the modified expanded perlite particles, on one hand, the traditional mechanical stirring is replaced by a pulse hydraulic mixing mode, the mixing of the modified expanded perlite particles, the sewage and the activated sludge is realized, and the crushing of the modified expanded perlite particle structure caused by extrusion collision due to the mechanical stirring is effectively avoided; on the other hand, after the modified expanded perlite particles are subjected to biofilm formation, activated sludge in the system and the aged biological membrane falling off from the carrier are gradually eliminated in a sludge discharge mode, so that microorganisms in the system keep high activity, the sewage treatment efficiency is kept at a high level, and the later-stage carrier input amount and input frequency are reduced; finally, by dissolving oxygen to the bottom of the reactor, simultaneously detecting the dissolved oxygen in the reactor by a DO detection system, and combining a pulse water inlet mode, an aerobic/anoxic/anaerobic reaction block is formed in the reactor, thereby being beneficial to the implementation of nitrification and denitrification and improving the sewage treatment efficiency.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a diagram of an aerobic granular sludge culture device, which comprises a water inlet tank 1, a lift pump 2, a head tank 3, a pneumatic valve 4, a sludge storage tank 5, a reactor 6, a movable baffle 7, a sludge discharge valve 8, a partition board 9, an aeration system 10, a DO online monitoring system 11, a reflux pump 12, a regulating valve 13, a regulating valve 14, a reflux water tank 15, a water outlet tank 16 and a partition board 17.

FIG. 2 is a diagram of a modified expanded perlite particle obtained by the gravity ballasting method in example 1.

FIG. 3 is a diagram of a modified expanded perlite particle obtained by the vacuum method and the gravity ballast method in example 2.

FIG. 4(a) is a graph showing the sedimentation of the modified expanded perlite particles obtained by the vacuum method and the gravity ballast method in example 2, and FIG. 4(b) is a graph showing the sedimentation of the modified expanded perlite particles obtained by the vacuum loading method in example 3.

FIG. 5 is a schematic representation of modified expanded perlite particles obtained by vacuum process in example 3.

FIG. 6 is the cross-sectional electron micrograph of the modified expanded perlite particles obtained by the vacuum process in example 3.

FIG. 7 is the electron microscopic image of the modified expanded perlite particles after filming in example 7.

FIG. 8 is a microscopic image of the sludge granules with the modified expanded perlite as the core in example 7.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

Moreover, the technical solutions in the embodiments of the present invention may be combined with each other, but it is necessary to be able to be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent, and is not within the protection scope of the present invention.

When numerical ranges are given in the examples, it is understood that both endpoints of each of the numerical ranges and any value therebetween can be selected unless the invention otherwise indicated. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs and the description of the present invention, and any methods, apparatuses, and materials similar or equivalent to those described in the examples of the present invention may be used to practice the present invention.

The invention provides a preparation method of modified expanded perlite particles, which comprises the following steps:

s1: preparing the pyrite powder slurry with the solid content of 1-15%, wherein the grain size of the pyrite powder is less than 10 mu m.

It can be understood that the solid content is the ratio of the mass of the pyrite powder to the total mass of the pyrite powder after water is added, and the unit is g/g.

Preferably, the pyrite powder is fine pyrite after crushing and screening treatment, and the sulfur content in the fine pyrite is more than 30%.

It can be understood that other micro-scale or nano-scale pyrite powder can be used as a substitute carbon source to be loaded on the expanded perlite particles to provide nutrition for the subsequent growth and enrichment of microorganisms.

the particle size of the expanded perlite particles is 0.5-4mm, and the pore diameter of the surfaces of the expanded perlite particles is larger than that of the pyrite powder, so that the pyrite powder can enter gaps inside the expanded perlite particles, and more attachment sites are provided for the growth of microorganisms.

It can be understood that the loading effect of the pyrite slurry is more facilitated by placing the dried expanded perlite particles in the negative pressure container; it will also be appreciated that wet expanded perlite is also suitable for use in this embodiment, but is less loaded than dry expanded perlite particles.

It can be understood that the negative pressure container can be a filter flask, the expanded perlite particles can be placed in the filter flask, the vacuum circulating water pump is started to form negative pressure of-0.1 Mpa in the filter flask, and then the pyrite powder slurry is injected into the filter flask.

It can also be understood that the pyrite powder slurry completely submerges the expanded perlite particles, so that the pyrite powder is fully combined with the expanded perlite particles, and the pyrite powder enters the internal honeycomb structure of the expanded perlite particles due to the negative pressure environment.

Preferably, the mass ratio of the expanded perlite particles to the pyrite powder is 2-10.

Preferably, the step S3 further includes a sieving process and a drying process, wherein the sieving process includes: the screening process comprises: enabling the settled particles to pass through a standard sieve of 20-40 meshes, and taking oversize products; the drying process comprises: and drying the oversize product, wherein the drying temperature is 105-150 ℃, and the drying time is 2-5 h.

It can be understood that the pyrite powder slurry can be kept stand for 0.5 to 1 hour after being added, and then water is added into the negative pressure container, so that the pyrite powder is fully combined with the perlite particles under the action of surface energy and gravity ballast;

it can be understood that the modified expanded perlite particles can sink to the bottom by reasonably controlling the water addition amount, and the unloaded expanded perlite particles are suspended (the expanded perlite particles are in a honeycomb structure and suspended in water), so that the layering effect is achieved; if the expanded perlite particles are modified in the suction filter flask, the water adding amount can be 3ml, and the liquid level after water is added can be 2-3 cm higher than the original liquid level.

It will be appreciated that the oversize can be placed on a sieve and washed with clean water and filtered until the undersize filtrate is clear.

The invention also provides modified expanded perlite particles prepared by any one of the preparation methods.

The invention also provides application of the modified expanded perlite particles prepared by the preparation method in sewage treatment.

It is understood that the modified expanded perlite can be placed in an aerobic granular sludge culture device for sewage treatment.

It is understood that the aerobic granular sludge cultivation apparatus may include the following structure: the device comprises a water inlet tank, a lifting pump, a high-level water tank, a pneumatic valve, a sludge storage tank, a reactor, a movable baffle, a sludge discharge valve, a partition board, an aeration system, a DO online monitoring system, a reflux pump, a regulating valve, a reflux water tank, a water outlet tank and a partition board.

It can be understood that, referring to fig. 1, the aerobic granular sludge cultivation apparatus mainly comprises: pulse structure, reaction structure and backflow discharge structure of intaking specifically as follows:

the pulse water inlet structure mainly comprises a water inlet water tank 1 and a high-level water tank 3 which are sequentially connected through a pipeline, wherein a lifting pump 2 is arranged on the pipeline connecting the water inlet water tank 1 and the high-level water tank 3, and a pneumatic valve 4 is arranged on the pipeline connecting the high-level water tank 3 and a reactor 6;

the reaction structure mainly comprises a reactor 6, the lower part of the reactor 6 is provided with a partition plate 9, the reactor 6 is connected with the sludge storage tank 5 through a partition plate 17, wherein the movable baffle 7 is positioned at one quarter of the upper part of the partition plate 17, the lower part of the reactor 6 is connected with a pneumatic valve 4 in a pulse water inlet structure, the upper part is connected with a backflow discharge structure through a pipeline, and the lower part of the reactor 6 is also connected with an aeration system 10 through a pipeline; the reaction structure further comprises a DO online monitoring system 11, wherein the DO online monitoring system 11 mainly comprises a first probe and a second probe, the first probe is arranged above the isolation plate 9 at a vertical distance of 10 cm, and the second probe is arranged above the first probe at a vertical distance of 40 cm; a sludge discharge valve 8 is arranged below the sludge tank.

The backflow discharge structure mainly comprises a backflow tank 15 and a water outlet tank 16, wherein the backflow tank 15 and the water outlet tank 16 are connected with the reactor 6 through pipelines, and the pipelines are also respectively provided with an adjusting valve 13 and an adjusting valve 14; the return tank 15 is also connected with the high-level water tank 3 through a pipeline, and a return pump 12 is arranged on the pipeline.

It can be further understood that, referring to fig. 1, the process of the present invention for treating sewage by using the aerobic granular sludge culture apparatus is as follows: quantitative modified expanded perlite particles are put into a reactor 6, after the particles are put into the reactor, sludge taken from the tail end of an aerobic pool is inoculated into the reactor 6, the sludge and the modified expanded perlite particles are fully mixed, after the mixing is finished, a lifting pump 2 is opened, sewage in a water inlet tank 1 is pressed into a high-level water tank 3, pulse water inlet is realized by controlling the opening and closing frequency of a pneumatic valve 4, and the opening and closing frequency is as follows: the pneumatic valve 4 is opened for 5-10 s and closed for 20-60 s; the water flow shearing force is formed in the reactor 6, the water flow shearing force can be further adjusted by further controlling the opening and closing frequency, and the aeration system 10 is combined to dissolve oxygen into the reactor 6, so that the microbial community is rapidly granulated; opening the movable baffle 7, and allowing the light sludge and the aged biological film (namely light material) falling off from the carrier to enter the sludge storage tank 5 from the movable baffle 7, wherein the sludge storage tank 5 needs to open a sludge discharge valve periodically for waste discharge; in addition, the supernatant liquid at the upper part of the reactor 6 overflows from the reactor 6, part of the supernatant liquid enters a return water tank 15, is pressed into the high-level water tank 3 through a return pump 12 to be combined with sewage, and the other part of the supernatant liquid directly enters an effluent water tank 16 and is discharged out of the system.

It can be further understood that the aeration system dissolves oxygen into the water body, so that gradient difference of dissolved oxygen is formed in the microorganism aggregate, and favorable conditions are created for autotrophic denitrification and synchronous nitrification-denitrification of sulfur.

Preferably, the application of the modified expanded perlite particles in sewage treatment comprises the following steps:

it will be appreciated that the sludge may be taken from the end of an aerobic tank of a conventional activated sewage treatment plant.

It will also be appreciated that, in theory, the activated sludge is in a full-tank fluidized state, taken from any point, and the purpose of inoculating the activated sludge is to introduce the sewage treatment microorganisms.

It will also be appreciated by those skilled in the art that in an aerobic sludge granule incubator, the volume of inoculated sludge can be up to three quarters of the reactor volume.

it can be understood that in the aerobic granular sludge culture device, sewage can be lifted to a high-level water tank from a water inlet water tank through a lifting pump, then the sewage is pressed into a reactor, pulse water inlet from bottom to top is realized at the bottom of the reactor through controlling a pneumatic valve, and water in the reactor is intensively stirred, so that the sludge, the sewage and the modified expanded perlite particles are fully mixed, and the sewage treatment efficiency is improved.

It will be appreciated that the flow rate of the sewage water is sufficient to agitate the body of water during the pulse of water.

Preferably, the method further comprises the following steps: oxygen was supplied to the bottom of the reactor.

It can be understood that oxygen can be fed into the reactor through an aeration system in the aerobic granular sludge culture device, and the formation of a dissolved oxygen gradient in the reactor is promoted by combining a pulse water feeding mode, so that an aerobic/anoxic/anaerobic reaction block is further formed from bottom to top.

It is also understood that the aeration intensity of the aeration system can be adjusted, so that the detection value in the DO online monitoring system meets the requirement.

Preferably, during the process of supplying oxygen to the bottom of the reactor, the dissolved oxygen in the reactor is detected by a DO online monitoring system: the DO online monitoring system comprises a first probe and a second probe;

It is understood that in an aerobic granular sludge cultivation apparatus, the bottom of the reactor may be a partition plate.

It can be understood that the first probe range represents that the dissolved oxygen amount per liter of water body is controlled to be 3-5mg within the first probe measurement range; similarly, the second probe range indicates that the dissolved oxygen amount per liter of water is controlled to be below 0.5mg in the second probe measurement range.

S4: collecting liquid overflowing from the upper part of the reactor;

preferably, in step S4, the collecting the liquid overflowing from the upper portion of the reactor includes:

part of liquid overflowing from the upper part of the reactor flows back to the bottom of the reactor in a mode of pulse water feeding from bottom to top; and conveying the rest of liquid overflowing from the upper part of the reactor to a liquid outlet device.

It can be understood that when the aerobic granular sludge culture device is used for treatment, the liquid (namely supernatant) overflowing from the upper part of the reactor partially enters the return water tank, is combined with the sewage in the high-level water tank through the return pump and partially enters the water outlet tank;

it will be appreciated that supernatant that does not enter the head tank is drained from the outlet tank into the outlet tank drain system.

It can also be understood that the supernatant discharged from the effluent discharge system satisfies the discharge requirements of the first class A standard of the discharge Standard of pollutants for municipal wastewater treatment plant (GB 18918-.

Wherein the reflux ratio of the sewage entering the reflux water tank is 50-100%;

It can be understood that the modified expanded perlite particles are filmed when a layer of light yellow biological film is clearly observed on the surfaces of the particles or the water output is detected to be stable and reach the standard.

It is understood that the light materials include light sludge and aged biofilm sloughed off from the carriers, and the light sludge is mainly composed of active microbial population with metabolic function, residues of endogenous respiration and autooxidation of microbes, refractory organic matters adsorbed by sludge flocs and inorganic matters adsorbed by the sludge flocs.

It can be understood that when being applied to aerobic granule mud culture apparatus, can open the adjustable fender, make light mud passes through the adjustable fender under the rivers effect from bottom to top and gets into in storing up the mud pond, in addition, can regularly open the mud valve, discharges dumped mud, guarantees mud valve discharge system's work efficiency and life.

It can be understood that the pyrite powder is loaded on the modified expanded perlite particles to provide an enrichment environment for sulfur autotrophic denitrifying bacteria, and an aerobic/anoxic microenvironment is formed after the modified expanded perlite particles are filmed.

It should also be understood by those skilled in the art that, as important indicators of the loading effect of the technical solution, the calculation of the unit loading amount (the mass of the pyrite powder loaded on the expanded perlite particles per unit mass) and the loading rate (the ratio of the loaded pyrite powder to the total pyrite powder input) mainly uses an equal volume method, and the steps thereof may include: s1: taking the total volume of the microorganism carrier loaded with the superfine powder as L and the total mass of the microorganism carrier as M, and recording the mass of the added pyrite powder as M; s2: transferring the dried modified expanded perlite part into a measuring cylinder, and fixing the volume to l ₁ ml, measuring its net weight m ₁ (ii) a Taking the floating microorganism carrier, drying and fixing the volume to l ₁ mL, determining the net weight m of the floating microbial carrier ₂ ；

Wherein l ₁ The mass of the superfine powder loaded on the microorganism carrier with volume is m ₁ -m ₂ The mass of the ultrafine powder loaded on the microbial carrier per unit mass is m ₁ -m ₂ /m ₂ (ii) a The mass of the microorganism carrier not loaded with the micron powder is L x m when the volume is L ₂ /l ₁ And the measured load is: (M-L.times.m) ₂ /l ₁ )/m。

To facilitate a further understanding of the invention by those skilled in the art, reference will now be made to the following examples:

wherein PE represents expanded perlite, and PY represents pyrite.

Example 1

Loading pyrite by gravity ballast method

1. Preparation procedure

2g of PE (0.5-4mm) is weighed in advance, 50mL of water is added into a beaker of 1 gPY-250 mL, magnetic stirring is carried out for 30min, the mixture is poured into a standard sieve of 40 meshes, unloaded PY powder is filtered out, and drying is carried out at 105 ℃ to obtain modified expanded perlite particles obtained by a gravity ballast method, wherein the modified expanded perlite particles obtained by the gravity ballast method are shown in figure 2. By the same way, different PYs were prepared: under the condition of PE proportioning, the unit load capacity and the total load rate of the modified expanded perlite particles are further obtained through a gravity ballast method.

2. Results of the experiment

The loading rate and unit loading of the expanded perlite particles and pyrite in different mass ratios when combined using the gravity ballast method are shown in table 1.

TABLE 1

Example 2

Vacuum method and gravity ballast method load PY

1. Preparation procedure

Pre-weighing 30g of PE (0.5-4mm) particles and 15gPY, placing the PE (dry) particles and the PY particles in a filter flask, preparing a 1L beaker, filling 300mL of water, starting a vacuum circulating water pump to form negative pressure in the filter flask, and injecting about 300mL of water into the filter flask when a vacuum degree dial (gauge pressure) of the vacuum circulating water pump reaches-0.1 Mpa, wherein the PE particles can be completely immersed in the water surface. Adding 300mL of water into the bottle, standing for 5min, sieving the settled PE particles through a 40-mesh standard sieve to remove the non-loaded PY until the filtrate under the sieve is clear, indicating that the sieving is finished, and then putting the PE particles on the sieve into an oven for drying, wherein the drying temperature is 105 ℃, and the drying time is 4h, so as to obtain the modified expanded perlite particles prepared by a vacuum method and a gravity pressure loading method; respectively measuring the volume of the upper floating PE particles and the volume of the sinking PE particles after drying, and calculating the sedimentation ratio; and further detecting and calculating to obtain unit load capacity and load rate.

2. Results of the experiment

300mL of PE (30g) particles are added into a filter flask, 300mL of water is treated by a vacuum method, the volume of the floating PE particles is 60mL, the calculated sedimentation ratio is 80%, and the PY amount of the PE load per unit mass is 0.17g/g, wherein the modified expanded perlite particles obtained by the vacuum method and the gravity ballast method are shown in figure 3, and the sedimentation condition is shown in figure 4 (a).

Example 3

Vacuum method loading PY

1. Preparation procedure

Pre-weighing 30g of PE (0.5-4mm) particles, placing the PE (dried) particles in a filter flask, preparing a 1L beaker, adding 15gPY into the beaker, adding water to prepare 300mL of slurry (the solid content is about 4.8%), turning on a vacuum circulating water pump to form negative pressure in the filter flask, and when a vacuum degree dial plate (gauge pressure) of the vacuum circulating water pump reaches-0.1 Mpa, injecting 300mL of slurry into the filter flask, wherein the PE particles can be completely immersed in the liquid surface. After finishing, adding 300mL of water into the bottle, standing for 5min, sieving the settled PE particles through a 40-mesh standard sieve to remove the non-loaded PY until the filtrate under the sieve is clear, indicating that the sieving is finished, and then putting the PE particles on the sieve into an oven for drying, wherein the drying temperature is 105 ℃, and the drying time is 4h, so as to obtain the modified expanded perlite particles prepared by the vacuum method; respectively measuring the volume of the upper floating PE particles and the volume of the sinking PE particles after drying, and calculating the sedimentation ratio; and further detecting and calculating to obtain the unit load.

2. Results of the experiment

The vacuum method can solve the problem of PE floating, and through the PE after vacuum treatment, sinking PE particles account for 80 percent of the total PE, namely the sinking ratio is 80 percent.

PY load is combined with a vacuum method, PY and water enter the inner pores of PE particles simultaneously in a negative pressure environment, and the observation of the inner section of PE can show that: the PY load in the PE is uniform, and the load effect is good. The loading rate of the PE with unit mass loaded with PY is greatly improved compared with other methods when the PY amount with unit mass is 0.6 g/g.

The modified expanded perlite particles obtained by the vacuum method are shown in figure 5, the sedimentation condition is shown in figure 4(b), and the cross-sectional electron microscope image of the modified expanded perlite particles obtained by the vacuum method is shown in figure 6. A comparison of the specific loading of the modified expanded perlite particles obtained according to the different methods obtained in examples 1, 2 and 3 is shown in Table 2.

TABLE 2

Example 4

Load condition of PE/PY with different proportions

1. Experimental procedure

Weighing 30g of PE (0.5-4mm, dry) particles, placing the particles in a filter flask, preparing a 1L beaker, respectively filling 3g, 18g and 30gPY, adding water to prepare 300mL of slurry (solid contents are respectively about 1%, 5.7% and 9.1%), starting a vacuum circulating water pump, vacuumizing to form negative pressure in the filter flask, and injecting 300mL of PY slurry into the filter flask when a vacuum degree dial (gauge pressure) of the vacuum circulating water pump reaches-0.1 Mpa, wherein the PE particles are completely immersed in the liquid surface. And adding 300mL of water into the bottle after immersion, standing for 5min, respectively collecting upper-layer floating PE particles and sinking PE particles, sieving the sinking PE particles through a 40-mesh standard sieve to remove the non-loaded PY until filtrate under the sieve is clear, indicating that the sieving is finished, and then putting the PE particles on the sieve into an oven for drying operation, wherein the drying temperature is 105 ℃, and the drying time is 4h, so as to obtain the modified expanded perlite particles. And collecting the settled particles, drying, and further measuring the unit load capacity and the load rate of the modified expanded perlite particles obtained by the vacuum loading method under different PE/PY ratios.

2. Results of the experiment

The unit loading and loading rate of the modified expanded perlite particles obtained by the vacuum loading method under different PE/PY ratios are shown in Table 3.

TABLE 3

The higher the PY/PE mass ratio is, the more PY is loaded on the PE per unit mass, and the smaller the loading is.

Example 5

Load conditions of different vacuum degree holding time

1. Experimental procedure

30g of PE particles (0.5-4mm, dry) were weighed into a filter flask, a 1L beaker was prepared, 30gPY was placed, and water was added to a volume of 300mL (about 9.1% solids). And (3) opening the vacuum circulating water pump to form negative pressure in the filter flask, keeping the vacuum degree for 1min when the vacuum degree dial plate (gauge pressure) of the vacuum circulating water pump reaches-0.1 Mpa, and injecting 300mL of PY slurry into the filter flask, wherein the PE particles can be completely immersed in the liquid level. Adding 300mL of water into the bottle after immersion, standing for 5min, layering to obtain upper floating PE particles and sinking PE particles, sieving the sinking PE particles through a 40-mesh standard sieve to remove the non-loaded PY until filtrate under the sieve is clear, indicating that the sieving is finished, collecting the PE particles on the sieve, drying at 105 ℃, wherein the drying time is 4h, obtaining modified expanded perlite particles prepared by a vacuum method under different vacuum degree holding times, and further calculating unit loading capacity and loading rate; similarly, samples with vacuum degree not maintained are prepared, and the unit load capacity and the load rate of the samples are calculated.

2. Results of the experiment

TABLE 4

The vacuum degree maintaining time is beneficial to improving the PY amount of the PE load per unit mass, but the influence is small.

Example 6

PY desorption test of PE particles

1. Experimental procedure

30g of PE particles (0.5-4mm, dry) were weighed into a filter flask, a 1L beaker was prepared, 10gPY slurry was charged, and water was added to a constant volume of 300mL (about 3.2% solids). And (3) opening a vacuum circulating water pump to form negative pressure in the suction flask, keeping the vacuum degree for 1min when a vacuum degree dial plate (gauge pressure) of the vacuum circulating water pump reaches-0.1 Mpa, and injecting 300mL of PY slurry into the suction flask, wherein the PE particles can be completely immersed in the liquid level. Adding 300mL of water into the bottle after immersion, standing for 5min, collecting upper-layer floating PE particles and sinking PE particles, screening out unloaded PY from the sinking PE particles through a 40-mesh standard sieve until filtrate under the sieve is clear, indicating that screening is finished, collecting part of PE particles on the sieve, drying at 105 ℃ for 4h to obtain modified expanded perlite particles, and further calculating the dried PE particles to obtain unit loading capacity and loading rate. And performing PY desorption test on the other part of the PE particles on the sieve, placing 10g of the collected undried sinking PE particles into a 250mL beaker, adding 200mL of water, starting magnetic stirring, treating the PE particles through the magnetic stirring at the rotating speed of 200rpm, so that the PY-loaded PE particles can be well dispersed in the water, collecting the PE particles after 2h of magnetic stirring, and drying at 105 ℃ for 4 h. And further calculating the unit load capacity and the load rate of the dried PE particles.

2. Results of the experiment

TABLE 5

The PY desorption amount is increased along with the longer stirring time, but the PY desorption amount is smaller, and the PY load is more stable.

Example 7:

in this embodiment, the effluent is from a fine grid of a municipal wastewater treatment plant, and the water quality characteristics are as follows: COD is 102-565 mg/L; ammonia Nitrogen (NH) ₄ ⁺ -N) the mass concentration is 13-28 mg/L; total Nitrogen (TN) mass concentration24-57 mg/L; the mass concentration of Total Phosphorus (TP) is 2-9 mg/L; the pH value is 6.8 to 7.5.

The modified expanded perlite prepared by the invention is added into a reactor of an aerobic granular sludge culture device, the adding amount is 30 percent of the effective volume of the reactor, and meanwhile, activated sludge taken from the tail end of an aerobic pool is inoculated into the reactor, and the concentration of the inoculated sludge is 3000 mg/L.

And (3) pressing sewage in the water inlet tank to a high-level water tank through a lifting pump, and simultaneously controlling the switching frequency of the pneumatic valve to pulse the sewage into the reactor from bottom to top, wherein the pneumatic valve is closed for 40s every time the pneumatic valve is opened for 10 s.

And adjusting the aeration intensity, controlling the DO concentration in a first probe range in the DO online monitoring system to be 3-5mg/L, controlling the DO concentration in a second probe range to be below 0.5mg/L, and forming DO concentration difference on a vertical gradient.

The sewage entering the reactor, the sludge and the modified expanded perlite particles are fully mixed under the action of water flow of pulse inflow water, then liquid (namely supernatant) overflowing from the upper part of the reactor is collected, the supernatant overflows from the upper part of the reactor, part of the supernatant enters a return water tank, is combined with the sewage in the high-level water tank through a return pump, and then returns to the bottom of the reactor from bottom to top in a pulse mode, wherein the reflux ratio is 50%; the other part enters the water outlet tank.

And at the 20 th operation of the reactor, finishing the film hanging of the modified expanded perlite particles, opening the movable baffle, allowing the light activated sludge and the aged biological film falling off from the carrier to enter the sludge storage tank under the action of water flow from bottom to top, periodically opening the sludge discharge valve, and eliminating the waste sludge in the sludge storage tank out of the system.

After the system runs stably, the sludge particles taking the modified expanded perlite as the core are enriched in the system, the particle size distribution is 0.5-4.5mm, a layer of compact biological membrane is observed to be wrapped on the carrier (wherein, the electron microscope picture of the modified expanded perlite particles after film hanging is shown in figure 7, and the electron microscope picture of the sludge particles taking the modified expanded perlite as the core is shown in figure 8), and an aerobic/anoxic microenvironment is formed by combining the load of PY, so that a microbial aggregate is formed; under the aeration condition, oxygen is dissolved into the water body to form a dissolved oxygen gradient difference.

In addition, the formed microorganism aggregate has good sedimentation performance, the sedimentation speed can reach 30-100m/h, and the sewage treatment capacity of the system is improved.

Continuously sampling and detecting the water quality of the effluent, wherein COD is 10-30 mg/L; ammonia Nitrogen (NH) ₄ ⁺ -N) the mass concentration is 0.2-0.8 mg/L; the mass concentration of Total Nitrogen (TN) is 7-10 mg/L; the mass concentration of Total Phosphorus (TP) is 0.2-0.5 mg/L.

In summary, in the above technical solutions of the present invention, the above are only preferred embodiments of the present invention, and the technical scope of the present invention is not limited thereby, and all equivalent structural changes made by using the contents of the specification and the drawings of the present invention or other related technical fields directly/indirectly applied thereto are included in the scope of the present invention.

Claims

1. A preparation method of modified expanded perlite particles is characterized by comprising the following steps:

2. The method for preparing modified expanded perlite particles as claimed in claim 1, wherein the pyrite powder is fine pyrite after being crushed and sieved, and the sulfur content in the fine pyrite is more than 30%.

3. The method for preparing the modified expanded perlite particles as claimed in claim 1, wherein the mass ratio of the expanded perlite particles to the pyrite powder is 1-10: 1.

4. The method as claimed in claim 1, wherein the step S3 further comprises a sieving process and a drying process, the sieving process comprises: enabling the settled particles to pass through a standard sieve with 20-40 meshes, and taking oversize products; the drying process comprises: and drying the oversize product, wherein the drying temperature is 105-150 ℃, and the drying time is 2-5 h.

5. A modified expanded perlite particle, characterized by being prepared according to the preparation method of any one of claims 1 to 4.

6. Use of the modified expanded perlite particles of claim 5 in sewage treatment.

7. The use of the modified expanded perlite particles of claim 6 in sewage treatment comprising the steps of:

s4: collecting liquid overflowing from the upper part of the reactor;

8. The use of the modified expanded perlite particles of claim 7 in sewage treatment, wherein said collecting of liquid overflowing from the upper portion of the reactor in step S4 comprises:

9. The use of the modified expanded perlite particles of claim 7 in sewage treatment, further comprising: oxygen was supplied to the bottom of the reactor.

10. The use of the modified expanded perlite particles of claim 7 in wastewater treatment, wherein the oxygen dissolved in the reactor is detected by a DO on-line monitoring system during the supply of oxygen to the bottom of the reactor: the DO online monitoring system comprises a first probe and a second probe;