CN111137973A

CN111137973A - Denitrification functional filler, filler ball, filling method and application

Info

Publication number: CN111137973A
Application number: CN201911289625.3A
Authority: CN
Inventors: 郭鹏; 王晶晶; 林重阳
Original assignee: Qingshang (suzhou) Environmental Technology Co Ltd
Current assignee: Qingshang (suzhou) Environmental Technology Co Ltd
Priority date: 2019-12-16
Filing date: 2019-12-16
Publication date: 2020-05-12

Abstract

The invention provides a denitrification functional filler which comprises, by mass, 30-50% of iron-carbon filler, 20-40% of scrap iron, 20-40% of sulfur and 5-20% of biological activated carbon. According to the novel iron and sulfur autotrophic denitrification process, the sludge production amount is low, the pH of a water body is kept stable through the coupling effect of sulfur and iron, the problems of generation of an iron-based surface inert film and consumption of sulfur autotrophic alkalinity in iron autotrophy are solved, the oxidation-reduction property of a biological activated carbon functional group, the main body conductivity and the high specific surface area biological activity are synchronously utilized, the biomass in a system is improved, the denitrification efficiency of the system is increased, the operation cost is reduced, and the water quality requirement is met.

Description

Denitrification functional filler, filler ball, filling method and application

Technical Field

The invention belongs to the technical field of new materials for water treatment, and particularly relates to a filler with a denitrification function, a filler ball, a filling method and application.

Background

Along with the increasing of the living standard of human beings, the discharge amount of nitrogen-containing organic or inorganic compounds generated in the production and living of human beings is increased, so that NO in the water body₃ ^-The pollution of-N is increasingly serious, the water quality on the ground surface is continuously deteriorated, and the pollution problem becomes more and more serious. Globally, surface water NO₃ ^-The distribution of N contamination is relatively broad and the degree of contamination is increasing. NO₃ ^-Contamination with-NHas become one of the most common pollution factors in global water bodies and is the most complex environmental problem in the world. NO in water₃ ^-the-N is mainly from urban domestic sewage, industrial wastewater, rural sewage, leachate seepage and the like.

The harm of excessive nutrient inorganic salts such as nitrogen (N), phosphorus (P) and the like in natural water body is embodied in the following aspects: 1. water eutrophication causes aquatic organisms to die and destroy water ecology; 2. endanger the survival of animals and plants, change the water source osmotic pressure of plant root systems, cause the anoxic poisoning of animals and the like; 3. affecting human health, inhibiting blood oxygen transfer capability, inducing cancer, and even endangering life.

Therefore, research and development of economic and efficient wastewater denitrification treatment technologies have become key and hot spots in the field of water pollution control engineering.

Currently, depending on the removal method, NO can be substantially removed₃ ^-The removal method of-N is classified into a physical method, a chemical method and a biological method.

Wherein the physical process removes NO₃ ^-the-N mainly includes a technique of relying on a physical reaction process such as a membrane separation method, an ion exchange method, an adsorption method and the like.

The membrane separation method mainly realizes the separation of water and solute according to the filtration action of a supporting membrane, and water molecules or specific anions and cations permeate a membrane component to realize the separation and removal of NO by applying a mode comprising mechanical pressure or electromotive force₃ ^--N. The technology belongs to separation technology, and can produce low NO₃ ^-Water with N content and high NO production₃ ^-Tail water of N concentration. The method has the advantages that the water quality of the produced water is good, all target pollutants in the water can be basically removed, but the defects are obvious, the capability is insufficient when high-concentration tail water is treated, and the treatment cost and the energy consumption are extremely high.

The ion exchange method mainly utilizes the exchange capacity of basic anion resin by adding Cl^-Or HCO₃ ^-With NO₃ ^--N exchange to remove NO from a body of water₃ ^--N. The ion exchange process being containing NO₃ ^-The water body of-N is subjected to ion exchange during the process of passing through the ion exchange resin packed bed. The ion exchange resin method has the advantages of convenient operation, good treatment effect, small influence by the surrounding environment and the like, and has the advantages of treating a small amount of wastewater under severe environment conditions, but when the ion exchange resin is saturated in adsorption, the adsorption material needs to be replaced or regenerated, so that the treatment cost is increased, and the popularization and application of the ion exchange technology are influenced.

Similar to ion exchange, adsorption also adsorbs NO by using materials with large adsorption capacity and specific surface area₃ ^--N to thereby realize NO₃ ^--removal of N. After the adsorption saturation, the adsorption material also needs to be regenerated, so that the long-term stable operation of the system is influenced, and the method can only be suitable for treating a small amount of sewage in severe environment.

In general, the physical denitrification method has high denitrification efficiency, convenient operation and control and stable effluent quality within the treatment capacity range, but only uses NO₃ ^-The concentration and enrichment of N cannot be fundamentally removed, so that subsequent NO₃ ^-The secondary treatment of-N is relatively expensive and has certain limitation in large-scale application.

The chemical method is mainly used for reducing NO in water body by reducing agent₃ ^--N. Reduction of NO by existing main chemical processes₃the-N technology is mainly a reduction method using micro-nano zero-valent iron as a reducing agent. The influences of factors including pH, temperature, buffer, zero-valent iron form and the like in the reaction process, and various influencing factors and effects such as analysis of reaction products and reaction byproducts and the like are reflected in a large number of documents. The main reaction process is as follows:

Fe+2H₃O⁺→Fe²⁺+H₂+2H₂O

Fe+NO₃ ^-+2H₃O⁺→Fe²⁺+NO₂ ^-+2H₂O

5Fe+2NO₃ ^-+12H₃O⁺→5Fe²⁺+N₂+18H₂O

4Fe+NO₃ ^-+10H₃O⁺→4Fe²⁺+NH₄ ⁺+13H₂O

the method is used for reducing NO₃The main disadvantage of the-N concentration is that the reaction product is predominantly NH₄ ⁺N, which is easy to cause secondary pollution, thereby greatly limiting the popularization and application of the method. Although there are many application studies and certain results for denitrification with Fe (O) as chemical reduction material, it is difficult to achieve complete NO removal by various methods including changing material combination, performing catalyst catalysis, changing zero-valent iron form, adjusting pH, etc₃-N on the basis of N₂As a main reaction product. Therefore, the chemical reduction method has high reaction efficiency and high speed, and can remove NO through chemical reaction₃N, but the disadvantages are also obvious, by-products are easily generated, secondary pollution is caused, and the treatment is complicated. The application range is limited, and the method is difficult to be suitable for removing NO in tail water of sewage treatment plants and natural river and lake water bodies₃ ^--N contamination situation.

Biological denitrification mainly utilizes the action of microorganisms to produce NO₃ ^--N is an electron acceptor, and [ H ] is an organic compound]S or Fe as electron donor to respire NO by denitrification process of microorganism₃Final conversion of-N to N₂Thereby completely removing NO₃ ^--N. The main reaction process is as follows: NO₃ ^-→NO₂ ^-→N₂. The main advantages of the biological denitrification reaction technology are reflected in high efficiency and low energy consumption, and are NO which is most widely applied in the field of water treatment₃ ^--one of the N treatment processes. Biological denitrification reactions are classified into heterotrophic denitrification reactions and autotrophic denitrification reactions according to the difference in the carbon source utilized.

The heterotrophic denitrification process mainly comprises the steps that heterotrophic denitrification bacteria utilize outside carbohydrates or other organic matters as energy required by self growth and reproduction, and NO in water is removed₃ ^--N. The reaction formula is as follows:

5(CH₂O)+4H⁺+4NO₃ ^-→2N₂+7H₂O+5CO₂

the common added carbon sources in the existing sewage treatment process include glucose, methanol, starch, sodium acetate and the like, and meanwhile, solid organic matters such as straws, corn cobs, wood chips and the like can also be used as carbon sources for heterotrophic denitrification reaction. The adding amount of the carbon source can directly influence the denitrification efficiency, and when the adding amount of the carbon source exceeds the standard, the carbon source residue can be generated in the effluent, so that the COD exceeds the standard; when the adding amount of the carbon source is insufficient, the reaction in the denitrification process is incomplete, and NO in effluent₃ ^-Failure of N to reach the standard or the presence of NO₃ ^--accumulation of N. Heterotrophic denitrification treatment of NO in water body through additional carbon source₃The situation of over-high-N content mainly has the following defects that the method can cause the propagation of a large number of microorganisms, the produced excess sludge amount is increased, the cost of an external organic carbon source is increased, and the running cost is increased. In addition, if the water quality (such as COD, NO) is changed₃ ^-N) is large, and how to adjust and control the carbon source dosage is also one of the important points. Reduction of NO by heterotrophic denitrification₃The main contradiction of the-N discharge technology in the present stage is reflected in the increase of the cost of the sewage treatment facility.

Compared with heterotrophic denitrification, the autotrophic denitrification process utilizes inorganic electron donors such as sulfide and H₂Sulfur, Fe, etc. as electron donors, and using these energies, carbon dioxide, carbonate, etc. are synthesized into cellular materials and subjected to a denitrification process. The autotrophic denitrification reaction does not need to add extra organic matters as a carbon source, can utilize carbon dioxide dissolved in natural water as an inorganic carbon source, and has a lower biological accumulation amount compared with heterotrophic denitrification. Autotrophic denitrification is classified into hydrogen autotrophic denitrification, iron autotrophic denitrification, and sulfur autotrophic denitrification according to the difference in electron donors.

In the hydrogen autotrophic denitrification reaction, denitrifying microorganisms are treated with H under the anoxic condition₂As electron donor, by oxidation of H₂Reduction of NO₃ ^--N obtaining energy for microbial survival and organic matter synthesis, the reaction formula is as follows:

NO₃ ^-+2.5H₂+H⁺→0.5N₂+3H₂O

because the hydrogen belongs to explosive gas, the transportation and storage cost is higher, the solubility of the hydrogen is lower, the utilization efficiency is not high, and the NO is removed by the autotrophic denitrification of the hydrogen₃ ^-The technology of the-N process, although already proven to be feasible, still has very few engineering cases for the operation of denitrification with hydrogen feed into the reactor.

To find safe and stable hydrogen as an electron donor, iron-based denitrification techniques have been developed. The zero-valent iron reacts with water in the water body to generate hydrogen, and when the hydrogen is utilized by denitrifying bacteria, the hydrogen partial pressure of the water body is reduced, the raw water is continuously subjected to the oxygen-free hydrolysis of the iron simple substance to generate hydrogen. Generation of H₂Continues to be utilized by denitrifying microorganisms, thereby converting NO₃ ^-Conversion of-N to N₂Wherein the reaction process is as follows:

in NO₃-in the presence of N, Fe undergoes a two-step microelectrolysis reaction in water:

anode: fe → Fe²⁺+2e^-

Fe²⁺→Fe³⁺+e^-

Cathode: 2H⁺+2e^-→2[H]→H₂

Fe and H under the action of chemical reduction or microorganisms₂Or Fe²⁺NO in water₃ ^-Reduction of-N to NH₄ ⁺-N or N₂。

NO₃ ^-+8e^-+7H₂O→NH₄ ⁺+10OH^-

NO₃ ^-+5e^-+3H₂O→N₂+6OH^-

The single iron autotrophic denitrification process is an alkali production process, the pH value in the system can be gradually increased, and finally an inert membrane for inhibiting the further corrosion of the iron-based surface to produce hydrogen is formed, so that the denitrification efficiency of the iron autotrophic denitrification process is limited.

The sulfur autotrophic denitrification reaction is based on sulfur oxidizing bacteria under the anoxic condition by utilizing reduced sulfur (such as S)^2-、S、SO₃ ^2-Etc.) as electron donor, with NO₃ ^--conversion of N to nitrogen to effect the autotrophic denitrification process. The reaction process is as follows:

5HS^-+8NO₃ ^-+3H⁺→5SO₄ ^2-+4N₂+4H₂O

5S+6NO₃ ^-+2H₂O→5SO₄ ^2-+3N₂+4H⁺

among them, sulfur is the most commonly used electron donor, and has the advantages of non-toxicity, low cost, stability at normal temperature and insolubility in water. The use of elemental sulfur for the autotrophic denitrification process consumes alkalinity. Thus, experimenters have had a way to provide alkalinity using limestone as a pH buffer, while limestone can combine with sulfate to form calcium sulfate precipitates to reduce sulfate emissions.

In recent years, some scholars combine autotrophic denitrification and heterotrophic denitrification reactions of different electron donors to achieve the aims of balancing pH, improving reaction efficiency, reducing ammonia nitrogen production and the like. The existing system comprises technological processes such as a combined electrolysis hydrogen production and sulfur autotrophic denitrification process, a sulfur autotrophic heterotrophic synergetic denitrification process and the like.

CN 110078198A, a denitrogenation filler ball and application thereof, which utilizes a solid organic carbon source to carry out denitrification, has already been introduced in the mainstream process/product of the industry, and is an improvement on the prior art.

CN 109607812A, a complex denitrifying medicament, adds a suitable carbon source by using self-cultured microorganisms as a main body for denitrification, and simultaneously performs a small amount of adsorption denitrification by using a physical method, which belongs to the category of biological and physical denitrification, but the addition of an organic carbon source still needs to be continuously ensured if the long-term effective application is maintained.

CN 109847699A "a composite filler for removing nitrogen and phosphorus and a preparation method" uses zeolite, active carbon and iron powder as main fillers to remove ammonia nitrogen and phosphate by physical adsorption, and mainly belongs to the category of the physical denitrification.

CN 109592797A, a method for preparing a denitrification material, mainly utilizes the combination of sulfur autotrophy and heterotrophy to carry out denitrification, belonging to the improvement of a heterotrophy denitrification process based on sulfur autotrophy reinforced solid carbon source.

CN 109110862A, a material for removing nitrogen and phosphorus and a preparation method thereof, mainly utilizes the principle of the chemical reduction of nitrate nitrogen by the iron powder to carry out modification on the corresponding iron powder by a method of adding a catalyst, an adhesive and a carbon-based electron transfer auxiliary material, thereby realizing the conversion rate of selective nitrate nitrogen exceeding 81 percent and the product reporting effect is far better than that of laboratory detection data in most of the existing documents.

CN 109650561A similar to the principle of the technical scheme in the patent, the main denitrification mode is completed by depending on autotrophic iron and sulfur microorganisms and heterotrophic microorganisms, and the filler mainly completes the supply of denitrification electron donor and anoxic environment. The proportion of the filler iron, sulfur and active carbon is about 20-30%, 30-40% and 8-10%, and the rest is composed of binder, catalyst, pH regulator and pore-forming agent. The technology designs the relative proportion of iron and sulfur according to the water quality, and reduces the components of the pH regulator; the catalyst is generated by the growth of microorganisms to accelerate the electron transfer of iron and sulfur, and the catalyst components are reduced; the biochar is added according to a certain proportion, and an electron absorption and release function is provided by utilizing active functional groups in the biochar component, so that the denitrification effect of the filler is improved, and the cost of the filler is reduced.

Disclosure of Invention

Aiming at the problems, the invention provides a denitrification functional filler, a filler ball, a filling method and application, wherein the denitrification functional filler and the filler ball are different in formula components, low in operation cost and good in effluent quality.

In order to solve the technical problems, the invention adopts the following technical scheme:

the first aspect of the invention provides a denitrification functional filler, which comprises, by mass, 30-50% of an iron-carbon filler, 20-40% of scrap iron, 20-40% of sulfur and 5-20% of biological activated carbon.

According to the novel iron and sulfur autotrophic denitrification process, the sludge production amount is low, the pH of a water body is kept stable through the coupling effect of sulfur and iron, the problems of generation of an iron-based surface inert film and consumption of sulfur autotrophic alkalinity in iron autotrophy are solved, the oxidation-reduction property of a biological activated carbon functional group, the main body conductivity and the high specific surface area biological activity are synchronously utilized, the biomass in a system is improved, the denitrification efficiency of the system is increased, the operation cost is reduced, and the water quality requirement is met.

Preferably, the iron-carbon filler contains 80-95% of iron and 5-15% of carbon by mass.

Preferably, the iron-carbon filler is in a rugby shape, the radius of a long axis of the iron-carbon filler is 7-9 cm, and the radius of a short axis of the iron-carbon filler is 2.5-3.5 cm.

Preferably, the length and the width of the scrap iron are 0.3-2 cm respectively, and the thickness of the scrap iron is 0.01-0.1 cm.

In the invention, the scrap iron is obtained by crushing and screening the scrap iron of industrial production and processing enterprises by a metal crusher.

Preferably, the particle size of the sulfur is 0.05-0.2 cm.

The second aspect of the invention provides a filler ball, which comprises the denitrification function filler, a filler bag filled with the denitrification function filler, and a filter ball containing the filler bag.

Preferably, the material of the filling bag is anti-corrosion non-woven fabric.

Preferably, the mass of the filler bag is 2-6% of that of the denitrification functional filler; the mass of the filter ball is 6-10% of that of the denitrification functional filler.

The preparation method of the filler ball comprises the following steps: and mixing the weighed denitrification functional filler, packaging the mixture in a filler bag, and then packaging the mixture into a filter ball, wherein the packaged filler ball is shown in the left diagram of fig. 1, and the filter ball is shown in the right diagram of fig. 1.

The packed ball needs to be stored in a dry and low-temperature place until being used for packing.

The third aspect of the invention is to provide a filling method, wherein the microorganism is filled into the filler ball by adopting a wet inoculation method.

Specifically, the filler balls, the activated sludge and effluent of a secondary sedimentation tank of a sewage treatment plant are filled into a reactor, after 20-30 hours, the effluent of the secondary sedimentation tank of the sewage treatment plant is continuously introduced, the hydraulic retention time is controlled to be 2-4 hours, microorganisms are selectively acclimated for 2-3 weeks, then the effluent of the secondary sedimentation tank of the sewage treatment plant is continuously introduced, the hydraulic retention time is controlled to be 1-1.5 hours, and then the microorganisms are selectively acclimated for 1-2 weeks, wherein the volume of the filler balls is controlled to be 40-70% of the volume of the reactor, and the concentration of the activated sludge is 800-1200 mg/L. .

Wherein the activated sludge is activated sludge of an oxidation ditch of a sewage plant or activated sludge of an anoxic pond in an AAO process.

The fourth aspect of the invention provides the denitrogenation functional filler, the filler balls and the application of the filler balls filled by the filling method in sewage treatment.

Due to the implementation of the technical scheme, compared with the prior art, the invention has the following advantages:

(1) when the material is used for denitrification, the requirement of the content of dissolved oxygen in a mobile phase is greatly relaxed compared with the prior denitrification process, and the total nitrogen removal rate can reach more than 50 percent when the DO concentration of the dissolved oxygen is 2-4mg/L in a production example and is reduced to below 4mg/L from 9 mg/L. Because denitrification needs to be carried out in an anoxic environment, a large amount of electrons are consumed by dissolved oxygen in a water body in the conventional modes of adding an organic carbon source, providing an inorganic electron donor and the like, and the material disclosed by the invention can greatly reduce the requirement of the electron donor and reduce the production cost.

(2) The material can be suitable for denitrification under the condition of low total nitrogen concentration (below 10 mg/L), after the total nitrogen standard of drainage of the existing part of sewage treatment plants is increased from 15mg/L to 10mg/L, the carbon-nitrogen ratio in the original municipal sewage is too low and is gradually exposed, so that the requirement of extra carbon source addition for drainage total nitrogen control is generated, and the total carbon source addition amount required by the actual operation process of the sewage treatment plants is in an increasing trend along with the effluent standard. In this case, the total nitrogen emission operating cost is further reduced and the operating cost is increased when the total nitrogen concentration is lower than 10mg/L by a carbon source adding mode, and the system can still stably operate for a long time under the condition that the total nitrogen concentration is lower than 10mg/L through verification of a productive example.

(3) The carbon-nitrogen ratio of the inlet water in the use example of the material is between 1.5 and 4 for a long time and is less than the optimal carbon-nitrogen ratio of 5: 1, and the material and denitrification reaction equipment used by the material are proved to achieve the aim of reducing the total nitrogen of the outlet water through autotrophic heterotrophic microorganism combination under the condition of the ordinary low carbon-nitrogen ratio.

(4) The reaction equipment utilizing the material can show that the pH value of the outlet water can be stably maintained between 6 and 7 through long-time water quality detection, and basically has no change (the pH value is increased/reduced by no more than 0.3) compared with the pH value of the inlet water of the reactor, so that the condition that the iron/sulfur coupling type autotrophic denitrification process can meet the requirements of the material design process on the insufficient improvements of the prior iron-sulfur independent autotrophic denitrification passivation, overlarge pH change and the like is met.

Drawings

FIG. 1 is a schematic structural diagram of a filler ball and a filter ball; wherein, the left picture is the packed ball after the encapsulation is finished, and the right picture is the filter ball.

Detailed Description

The following examples are intended to illustrate several embodiments of the present invention, but are not intended to limit the invention to these embodiments. It will be appreciated by those skilled in the art that the present invention encompasses all alternatives, modifications and equivalents as may be included within the scope of the claims.

Example 1:

and (3) denitrification functional filler: 31.4 parts of iron carbon filler, 27.5 parts of scrap iron particles, 27.5 parts of sulfur particles and 7.8 parts of biological activated carbon. Wherein the mass percentage of each component in the iron-carbon filler is 88 percent of iron, carbon and adhesive to 8 percent of 4 percent, the iron-carbon filler is in the shape of rugby, the radius of a long shaft is 8 plus or minus 1cm, and the radius of a short shaft is 3 plus or minus 0.5 cm; the length and width of the iron filings particles are 0.6cm, and the thickness of the iron filings particles is 0.06 cm; the sulphur particles are selected to have a particle size of about 0.2 cm.

Filler ball: 3.9 parts of anticorrosive non-woven fabric and 2 parts of filter ball.

The denitrification functional filler is weighed and then completely mixed, packaged in an anticorrosive non-woven fabric filler bag and then packaged in a filter ball. And after the packing ball is packaged, the filler ball needs to be stored in a dry and low-temperature place for later use.

The filling method comprises the following steps: the prepared filler balls are inoculated in the equipment reactor by a wet method, wherein the filler balls occupy 55 +/-5% of the reactor space; the activated sludge used for inoculation in wet filling is activated sludge of an oxidation ditch process of a sewage treatment plant in Wuyi, Zhejiang province, the activated sludge is diluted to 1000mg/L by using effluent of a secondary sedimentation tank of the sewage treatment plant and then is completely mixed and filled with filler balls, and after the filling is finished, the effluent of the secondary sedimentation tank of the sewage treatment plant begins to be domesticated after microorganisms grow and attach for 24 hours. And (3) keeping the water inflow quantity stable to ensure that the primary hydraulic retention time is stabilized at 3 hours, and the primary microorganism selective acclimatization accumulation time is 2 weeks. The hydraulic retention time was adjusted to the target value of 1.43 hours and the cultivation was continued for 1 week.

The application comprises the following steps: continuously monitoring the average value of the water inlet (the water outlet of a secondary sedimentation tank of a sewage treatment plant) of the denitrification equipment and the average value of the water outlet of the equipment in two weeks, wherein the pH value of the water inlet/outlet is 6.71/6.67, the Dissolved Oxygen (DO) of the water inlet/outlet is 5.36/3.84mg/L, the nitrate nitrogen of the water inlet/outlet is 5.75/1.78mg/L, the ammonia nitrogen of the water inlet/outlet is 0.24/0.34mg/L, the COD of the water inlet/outlet is 21/22mg/L, the hydraulic retention time of the equipment is maintained to be 1.43 hours, the total nitrogen removal effect of the equipment is about 63.46 percent, and the total nitrogen of the water outlet is 2.26 mg/L.

Example 2:

and (3) denitrification functional filler: 31.4 parts of iron carbon filler, 27.5 parts of scrap iron particles, 27.5 parts of sulfur particles and 7.8 parts of biological activated carbon. Wherein the mass percentage of each component in the iron-carbon filler is 88 percent of iron, 8 percent of carbon and 4 percent of binder, the iron-carbon filler is in the shape of rugby, the radius of a long shaft is 8 plus or minus 1cm, and the radius of a short shaft is 3 plus or minus 0.5 cm; the length and width of the iron filings particles are 0.6cm, and the thickness of the iron filings particles is 0.06 cm; the sulphur particles are selected to have a particle size of about 0.2 cm.

The filling method comprises the following steps: the prepared filler balls are inoculated in the equipment reactor by a wet method, wherein the filler balls occupy 55 +/-5% of the reactor space; the activated sludge used for inoculation in wet filling is activated sludge of an oxidation ditch process of a sewage treatment plant in Wuyi, Zhejiang province, the activated sludge is diluted to 1000mg/L by using effluent of a secondary sedimentation tank of the sewage treatment plant and then is completely mixed and filled with filler balls, and after the filling is finished, the effluent of the secondary sedimentation tank of the sewage treatment plant begins to be domesticated after microorganisms grow and attach for 24 hours. And (3) keeping the water inflow quantity stable to ensure that the primary hydraulic retention time is stabilized at 3 hours, and the primary microorganism selective acclimatization accumulation time is 2 weeks. Adjusting the hydraulic retention time to the target value of 1.17 hours, and continuing to maintain the acclimatization for 1 week.

The application comprises the following steps: continuously monitoring the average value of the water inlet (the water outlet of a secondary sedimentation tank of a sewage treatment plant) of the denitrification equipment and the average value of the water outlet of the equipment in two weeks, wherein the pH value of the water inlet/outlet is 6.78/6.50, the Dissolved Oxygen (DO) of the water inlet/outlet is 5.28/4.04mg/L, the nitrate nitrogen of the water inlet/outlet is 6.05/2.80mg/L, the ammonia nitrogen of the water inlet/outlet is 0.22/0.10mg/L, the COD of the water inlet/outlet is 21/21mg/L, the hydraulic retention time of the equipment is 1.17 hours, the total nitrogen removal effect of the equipment is about 46.60 percent, and the total nitrogen of the water outlet is 3.46 mg/L.

Comparative example 1:

the filler component: 33.3 wt% of iron-carbon filler, 33.3 wt% of sulfur particles, 16.7 wt% of coarse sand and 16.7 wt% of limestone.

Selecting raw materials: wherein the mass percentage of each component in the iron-carbon filler is 88 percent of iron, carbon and adhesive to 8 percent of 4 percent, the iron-carbon filler is in the shape of rugby, the radius of a long shaft is 8 plus or minus 1cm, and the radius of a short shaft is 3 plus or minus 0.5 cm; selecting sulfur with a particle size of about 0.2 cm; the grain size of the coarse sand and the limestone is about 0.5-3 cm.

The application of the comparison product is as follows: the filler is weighed and then filled according to the method of example 1, and then the average value of the denitrification equipment inlet water (the sewage treatment plant secondary sedimentation tank outlet water) and the equipment outlet water in two weeks is continuously monitored, the pH of the inlet/outlet water is 6.71/6.34, the Dissolved Oxygen (DO) of the inlet/outlet water is 5.38/3.34mg/L, the nitrate nitrogen of the inlet/outlet water is 5.75/3.63mg/L, the ammonia nitrogen of the inlet/outlet water is 0.24/0.21mg/L, the COD of the inlet/outlet water is 20/22mg/L, the hydraulic retention time of the equipment is 1.71 hours, the total nitrogen removal effect of the equipment is about 32.93 percent, and the total nitrogen of the outlet water is 4.15 mg/L.

Comparative example 2:

the filler component: 33.3 wt% of iron-carbon filler, 33.3 wt% of sulfur particles, 16.7 wt% of coarse sand and 16.7 wt% of limestone

The application of the comparison product is as follows: the filler is weighed and then filled according to the method of the embodiment 2, the average value of the denitrification equipment inlet water (the outlet water of the secondary sedimentation tank of the sewage treatment plant) and the equipment outlet water in two weeks is continuously monitored, the pH of the inlet/outlet water is 6.78/6.23, the Dissolved Oxygen (DO) of the inlet/outlet water is 5.26/2.62mg/L, the nitrate nitrogen of the inlet/outlet water is 6.05/1.95mg/L, the ammonia nitrogen of the inlet/outlet water is 0.22/0.28mg/L, the COD of the inlet/outlet water is 20/23mg/L, the hydraulic retention time of the equipment is 2.31 hours, the total nitrogen removal effect of the equipment is about 64.72 percent, and the total nitrogen of the outlet water is 2.29 mg/L.

Comparative example 3:

the filler component: 50 wt% of pyrite, 25 wt% of coarse sand and 25 wt% of limestone.

Selecting raw materials: wherein the particle size of the pyrite is about 0.2-2.0 cm; the grain size of the coarse sand and the limestone is about 0.5-3 cm.

The application of the comparison product is as follows: the filler is weighed and then filled according to the method of example 1, the average value of the denitrification equipment inlet water (the sewage treatment plant secondary sedimentation tank outlet water) and the equipment outlet water in two weeks is continuously monitored, the pH of the inlet/outlet water is 6.71/6.39, the Dissolved Oxygen (DO) of the inlet/outlet water is 5.43/3.43mg/L, the nitrate nitrogen of the inlet/outlet water is 5.75/3.15mg/L, the ammonia nitrogen of the inlet/outlet water is 0.24/0.37mg/L, the COD of the inlet/outlet water is 20/22mg/L, the hydraulic retention time of the equipment is 1.88 hours, the total nitrogen removal effect of the equipment is about 38.56%, and the total nitrogen of the outlet water is 3.80 mg/L.

Comparative example 4:

The application of the comparison product is as follows: the filler is weighed and then filled according to the method of the embodiment 2, the average value of the denitrification equipment inlet water (the outlet water of the secondary sedimentation tank of the sewage treatment plant) and the equipment outlet water in two weeks is continuously monitored, the pH of the inlet/outlet water is 6.78/6.08, the Dissolved Oxygen (DO) of the inlet/outlet water is 5.46/3.52mg/L, the nitrate nitrogen of the inlet/outlet water is 6.05/4.90mg/L, the ammonia nitrogen of the inlet/outlet water is 0.22/0.08mg/L, the COD of the inlet/outlet water is 21/21mg/L, the hydraulic retention time of the equipment is 1.41 hours, the total nitrogen removal effect of the equipment is about 8.74 percent, and the total nitrogen of the outlet water is 5.92 mg/L.

As can be seen from the above example 1 and comparative example 4, the denitrification effect (63.46%) of the example is obviously better than that of the comparative example (8.74%) under the same running process (hydraulic retention time); the denitrification effect (64.72%) in the comparative example 2 can reach the similar effect (63.46%) with the example 1, but the hydraulic retention time exceeds 50% of the example, namely, the material of the comparative example needs to increase about 50% for achieving the corresponding effect, namely, the construction and running cost. According to the embodiment and the proportion, the coupled iron-carbon-sulfur autotrophic enhanced denitrification system after the microbial gain effect can greatly reduce the denitrification production construction and operation cost of the common autotrophic denitrification process; meanwhile, the process is also suitable for the deep denitrification treatment process under the condition of low total nitrogen concentration; particularly, the method has the characteristic of being suitable for removing total nitrogen under the condition of high dissolved oxygen, and can further reduce the carbon source waste condition caused by the dissolved oxygen in the water body compared with the common organic carbon source adding.

The present invention includes but is not limited to the above embodiments, and those skilled in the art can convert more embodiments within the claims of the present invention.

Claims

1. The filler with the denitrification function is characterized in that: the iron-carbon composite material comprises, by mass, 30-50% of iron-carbon filler, 20-40% of scrap iron, 20-40% of sulfur and 5-20% of biological activated carbon.

2. The denitrification functional filler according to claim 1, wherein: the iron-carbon filler comprises 80-95% of iron and 5-15% of carbon by mass.

3. The denitrification functional filler according to claim 1, wherein: the iron-carbon filler is in a rugby shape, the radius of a long axis of the iron-carbon filler is 7-9 cm, and the radius of a short axis of the iron-carbon filler is 2.5-3.5 cm.

4. The denitrification functional filler according to claim 1, wherein: the length and the width of the scrap iron are 0.3-2 cm respectively, and the thickness of the scrap iron is 0.01-0.1 cm.

5. The denitrification functional filler according to claim 1, wherein: the particle size of the sulfur is 0.05-0.2 cm.

6. A filled ball characterized by: comprising the denitrification function filler of any one of claims 1 to 5, a filler bag filled with the denitrification function filler, and a filter ball containing the filler bag.

7. The filler ball of claim 6 wherein: the material of the filling bag is anti-corrosion non-woven fabric.

8. The filler ball of claim 6 wherein: the mass of the filler bag is 2-6% of that of the denitrification functional filler; the mass of the filter ball is 6-10% of that of the denitrification functional filler.

9. A method of filling, characterized by: the packing ball of any one of claims 6 to 8 is filled with microorganisms by a wet inoculation method.

10. The filling method according to claim 9, wherein: and (2) filling the filler balls, the activated sludge and the effluent of the secondary sedimentation tank of the sewage treatment plant into a reactor, after 20-30 hours, continuously introducing the effluent of the secondary sedimentation tank of the sewage treatment plant and controlling the hydraulic retention time to be 2-4 hours, selectively acclimating the microorganisms for 2-3 weeks, then continuously introducing the effluent of the secondary sedimentation tank of the sewage treatment plant and controlling the hydraulic retention time to be 1-1.5 hours, and selectively acclimating the microorganisms for 1-2 weeks, wherein the volume of the filler balls is controlled to be 40-70% of the volume of the reactor, and the concentration of the activated sludge is 800-1200 mg/L.

11. Use of the denitrification function filler of any one of claims 1 to 5, the filler ball of any one of claims 6 to 8, or the filler ball filled by the filling method of claim 9 or 10 in sewage treatment.