CN101121115A - A kind of denitrification and dephosphorization carrier and its application - Google Patents

Abstract

The invention belongs to the technical field of water treatment, and in particular relates to the preparation and application of a nitrogen and phosphorus removal carrier. The carrier of the invention can protect the water environment by performing denitrification and phosphorus removal treatment on industrial wastewater containing ammoniacal nitrogen and inorganic phosphorus, domestic sewage and pollution sources (water) in non-point source pollution. The nitrogen and phosphorus removal carrier of the present invention is characterized in that the dry basis of the finished product is 200 kg and the components by weight are as follows: clinoptilolite powder (90% crossing 100 mesh exchange capacity is more than 100 cmol (+)/kg) 100 ~120kg; gypsum powder (90% over 100 mesh) 50~70kg; industrial salt with a particle size of 2-3cm 10kg; ordinary Portland cement (label 325-525) 20kg; pine sawdust 2kg; supplementary water 100- 200kg. The invention also discloses the preparation method and application of the carrier.

Description

A kind of denitrification and dephosphorization carrier and its application

technical field

The invention belongs to the technical field of water treatment, in particular, the invention relates to the preparation and application of a nitrogen and phosphorus removal carrier. The carrier of the invention can protect the water environment by performing denitrification and phosphorus removal treatment on industrial wastewater containing ammoniacal nitrogen and inorganic phosphorus, domestic sewage and pollution sources (water) in non-point source pollution.

technical background

The eutrophication process of rivers, lakes and reservoirs is mainly caused by the input sewage containing nitrogen and phosphorus nutrients (mainly ammoniacal nitrogen and inorganic phosphorus) that exceed the self-purification capacity of these water bodies. A very important task in the field of water environment protection is to adopt effective technologies to remove nitrogen and phosphorus-containing water sources to a certain extent before entering the above-mentioned water bodies, so as to ensure the safety of the ecological environment of the water bodies.

According to the search, the invention patent applications for various types of sewage denitrification and phosphorus removal in China's invention patents have a trend of accelerated growth in recent years. The current relevant patent documents are as follows:

The document with the application number of 200410084313 discloses a method for preparing zeolite synthesized from fly ash and its application. Its core technology is to use fly ash as the main raw material, add aluminum, silicon, chlorine or fluorine, etc. After mixing, add metal alkali solution and synthesize fly ash zeolite through hydrothermal synthesis reaction, then transform and activate water-soluble metal salt solution, and obtain fly ash synthetic zeolite after solid-liquid separation; The synchronous adsorption and purification ability of fly ash synthetic zeolite to ammonia nitrogen and phosphate can realize the simultaneous denitrification and phosphorus removal of sewage, and the powdered fly ash synthetic zeolite can also be directly added to sewage for simultaneous denitrification and phosphorus removal. This method requires complex chemical reactions to transform and activate the raw materials, and the fly ash synthetic zeolite is obtained after solid-liquid separation.

The application number is 200510046987, which discloses a biological aerated filter filler and its preparation method. The method uses clay and diatomaceous earth as the main raw materials, and iron slag and carbon black are added on this basis; the weight percentage of each component is as follows : Clay 46.5%-87.5%, iron slag 11.5%-52.5%, carbon black 1.0-2.0%, diatomaceous earth 0-5.0%. Preparation method: dry the iron slag in the air, ball mill, pass through a 200-mesh sieve, and mix the raw materials; granulate the filler with a particle size of 2-8mm, and spread it out for 2 hours; roast the filler at 1100-1200°C for 20-30 minutes; sieve the filler and put it into storage , this technology improves the nitrogen and phosphorus removal effect of the biological aerated filter process. Compared with the ceramsite filter material, the total nitrogen removal rate is increased by 20%, and the total phosphorus removal rate is increased by 5%. The cost of raw materials is at least 10%, but the method requires ball milling and high-temperature calcination of raw materials.

The document whose application number is 200510048671 discloses a preparation method of a rare earth adsorbent for denitrification and dephosphorization of sewage. The technical process is to soak powdered zeolite, diatomaceous earth or alumina with a particle size of 60-100 mesh in distilled water for 15- 30min, filter and dry at 100-430℃ for 1-2 hours, add to the prepared rare earth hydroxide solution according to the designed solid-to-liquid weight ratio, stir at room temperature for 45-60 minutes, stand and impregnate for 15-20 minutes After 1 hour, filter the solution to obtain a filter cake and filtrate. The filter cake is roasted at a temperature of 300-600° C. for 0.5-2 hours and then sieved to obtain an adsorbent with a pore size of 0.3nm-0.5nm. The adsorbent can remove nitrogen and phosphorus in sewage at the same time. The adsorption capacity for nitrogen reaches 15-20mg/g, and the adsorption capacity for phosphorus reaches 22-25mg/g. The capacity is only reduced by 6%-7%. This method not only requires the raw materials to undergo a chemical reaction, but then the materials need to be filtered, roasted, crushed, and screened before they can be produced, and roasting is still required for regeneration.

The application number is 200610010634, which discloses a regeneration method of rare earth adsorbent after denitrification and dephosphorization of sewage. The method is to apply the saturated rare earth adsorbent after denitrification and dephosphorization of sewage. The weight ratio of sodium chloride solution in L, saturated rare earth adsorbent and regeneration solution is 1:50-70, and the regeneration solution with a line speed of 2-5m/h is used for cyclic desorption treatment, and lye is used to regulate regeneration during the treatment process The pH value of the solution is between 8-14, desorbing for 3-4 hours; filtering, and then using an activation solution prepared from the same rare earth elements as the saturated rare earth adsorbent to perform cyclic activation and impregnation treatment on the desorbed rare earth adsorbent; After filtration, drying and roasting, regeneration is obtained, and its adsorption capacity reaches more than 90% of the original adsorbent. Its defect is the same as the above-mentioned method, not only the raw materials need to be chemically reacted first, and then the materials need to be filtered, roasted, crushed and sieved before they can be produced, and roasting is still required for regeneration.

The application number is 200610010644, which discloses a modified natural and self-made floating carrier and mesoporous molecular sieve denitrification and phosphorus removal material, preparation and application. The nitrogen and phosphorus removal material includes rare earth lanthanum ions, cerium ions, metal aluminum ions, calcium ions Or its combination is 5-33%, and the balance is light aggregate with large specific surface; Rare earth lanthanum ion, cerium ion, metal aluminum ion, calcium ion or their combination is 3-20%, fine combination of large specific surface light aggregate 50-85%, fly ash 5-10%, surfactant 0.5-1%, cement 1-5%, the balance is double ash powder; rare earth lanthanum ion, cerium ion, metal aluminum ion, calcium ion or their combination 10-50%, and the balance is silicon-based mesoporous molecular sieve. The prepared adsorbent has large specific surface area, high adsorption capacity and high efficiency. Although this method also prepares nitrogen and phosphorus removal materials, the raw materials for the preparation are rare earth elements, and this preparation method virtually increases the production cost of the adsorbent.

The application number is 200610086102, which discloses a method for removing nitrogen and phosphorus in eutrophic water bodies by immobilizing sludge. In this invention, domesticated sludge is embedded and fixed on a carrier by immobilization technology to make immobilized sludge pellets, and For its pre-anaerobic treatment, the pre-treated immobilized sludge pellets are used for denitrification and phosphorus removal of eutrophic water bodies. The carrier of the immobilized sludge is sodium alginate, and the embedded sludge is a self-adapted sludge with high efficiency of denitrification and phosphorus removal. This method has good denitrification and phosphorus removal effects when treating eutrophic water bodies, and the solid-liquid separation is easy. Although the method is to prepare the adsorbent into pellets, the adsorbent itself is a kind of sludge, and its adsorption performance will decrease. It changes with the characteristics of sludge, so its removal effect on nitrogen and phosphorus is difficult to be stable.

Although the above-mentioned nitrogen and phosphorus removal materials (or adsorbents, or carriers) for removing nitrogen and phosphorus in sewage have relatively high removal rates for nitrogen and phosphorus, their respective preparation processes are complicated. In addition, none of the existing patents indicated the appropriate concentration ranges for denitrification and phosphorus removal, and the disclosures in the patents were not sufficient, making it difficult for those skilled in the art to implement their inventions according to the instructions and achieve the claimed inventive effects.

Contents of the invention

The purpose of the present invention is to overcome the defects of the prior art and develop a carrier for removing nitrogen and phosphorus in sewage with good adsorption performance, simple preparation process and low preparation cost. The nitrogen and phosphorus removal carrier prepared by the invention has high mechanical strength, can simultaneously remove nitrogen and phosphorus in sewage, has high removal rate, has no primary pollution, and meets the needs of current sewage treatment.

The present invention is achieved like this:

The carrier of the present invention uses natural zeolite and gypsum as main materials, supplemented by raw materials such as cement, coarse salt, pine sawdust, etc., through material mixing, adding water and plasticizing, forming holes, and processing into a nitrogen and phosphorus removal carrier (its preparation process and technology) See Figure 1 for the route. The core technology of implementing the present invention is to add a certain proportion of gypsum powder to the natural zeolite powder with a higher cation exchange capacity and fully mix it with a stirrer. Stir the pine wood sawdust evenly. When the mixed material has no heterogeneity, gradually add a certain amount of water and mix it. When the material becomes plastic, stop mixing. Use a briquette granulator to squeeze the material into a spherical carrier. The formed spherical carrier is submerged in water and soaked for 1 week, during which the filler particles are stirred for half an hour every day, then the soaking water is discarded, and the carrier is drained to become the denitrification and phosphorus removal carrier of the present invention.

Concrete technical scheme of the present invention is:

A nitrogen and phosphorus removal carrier, the components by weight are as follows:

Based on the dry basis of the finished product as 200kg:

Clinoptilolite powder (90% through 100 mesh exchange capacity above 100cmol(+)/kg) 100～120kg

Gypsum powder (90% over 100 mesh) 50～70kg

Industrial salt (particle size 2-3cm) 10kg

Ordinary Portland cement (label 325-525) 20kg

Pine sawdust 2kg

Add fresh water 100-200kg

Prepare as follows:

1) According to the formula, mix clinoptilolite powder and gypsum powder with a powder mixer for 5-10 minutes to obtain material 1;

2) Under stirring conditions, add industrial salt, ordinary portland cement, and pine sawdust to material 1, and continue mixing, subject to the fact that there is no sign of unmixed material with the naked eye, to obtain material 2;

3) Spray the material 2 obtained in step 2) with clear water under stirring, and observe the plasticity of the material to obtain material 3;

4) The material 3 obtained in step 3) is made into a 3-5 cm spherical fresh carrier with an extrusion granulator;

5) submerging the fresh carrier obtained in step 4) with water, making the carrier pore-forming, and gradually hardening the cement in the carrier;

6) The carrier submerged in step 5) is stirred with water for 30 minutes every day, so that the compressive strength of the prepared carrier reaches 65-75N, and the carrier is drained for later use.

According to the aforementioned preparation method, one of the optimized formulas, the components by weight are as follows:

Based on the dry basis of the finished product as 200kg:

Clinoptilolite powder (90% through 100 mesh exchange capacity above 100cmol(+)/kg) 100kg

Gypsum powder (90% over 100 mesh) 70kg

Industrial table salt (particle size 2-3cm) 10kg

Ordinary Portland cement (label 425) 20kg

Pine sawdust 2kg

Add 200kg of clean water.

According to the aforementioned preparation method, wherein another optimized formula, the components by weight are as follows:

Clinoptilolite powder (90% through 100 mesh exchange capacity above 100cmol(+)/kg) 110kg

Gypsum powder (90% over 100 mesh) 60kg

Industrial table salt (particle size 2-3cm) 10kg

Ordinary Portland cement (label 325) 20kg

Pine sawdust 2kg

Add water 150kg.

According to the aforementioned preparation method, wherein the best formula, the components by weight are as follows:

Based on the dry basis of the finished product as 200kg:

Clinoptilolite powder (90% through 100 mesh exchange capacity above 100cmol(+)/kg) 120kg

Gypsum powder (90% over 100 mesh) 50kg

Industrial salt particle size (2-3cm) 10kg

Ordinary Portland cement (label 525) 20kg

Pine sawdust 2kg

Add water 100kg.

The denitrification and phosphorus removal carrier prepared by the present invention has good economic benefits. According to the comparable market price, every ton of the nitrogen and phosphorus removal carrier (containing 50% zeolite, 35% gypsum, 5% industrial salt and 10% cement) is produced, The cost of materials is about RMB 257.

The denitrification and dephosphorization carrier prepared by the present invention has a good use effect. According to the calculation based on the mass balance, under the premise of ensuring the exchangeable quality of the zeolite, each ton of the carrier can intercept and process 4-5kg of NH ₄ ⁺ -N, and the intercepted The NH ₄ ⁺ -N in the carrier is removed by denitrification to generate N ₂ . Therefore, in theory, the carrier can be used repeatedly for denitrification; 55.8kg of inorganic phosphorus can be removed per ton of carrier, and the interception effect of phosphorus in sewage containing 0.25mg/L of phosphorus (flow 0.05m ³ /s) can reach 10 years long.

The reaction kinetics experiment shows that the rate constant of NH ₄ ⁺ -N interception by the nitrogen and phosphorus removal carrier of the present invention is 0.02h ^-1 , the half-life of intercepting 4mg/L NH ₄ ⁺ -N is between 34 and 37h, and the removal of inorganic The rate constant of phosphorus is between 0.2 and 0.3h ^-1 , and the half-life of removing 5mg/L inorganic phosphorus is between 3 and 4h.

Technical principle of the present invention is:

Some natural minerals, such as zeolites, have the ability to trap inorganic ions. Zeolite has good thermal stability, acid resistance, high temperature resistance, radiation resistance, and more importantly, ion exchange properties, which allow zeolite to exchange NH ₄ ⁺ in the solution. In addition to exchangeable minerals, some minerals are slightly soluble. Gypsum is a slightly soluble mineral, its solubility is 4 orders of magnitude higher than calcium carbonate, 3 orders of magnitude higher than monocalcium phosphate, and higher than calcium phosphate. Therefore, putting gypsum and dissolved inorganic phosphorus together can convert gypsum into calcium phosphate, thereby removing inorganic phosphorus in water. The present invention cleverly uses minerals with special properties such as zeolite and gypsum to prepare the nitrogen and phosphorus removal carrier of the present invention.

The beneficial effects of the present invention are:

1) The preparation process of the denitrification and dephosphorization carrier of the present invention is very simple, and the raw materials are mixed, mixed and formed, and hardened, and the energy consumption is low and the raw material cost is low;

2) The present invention fully considers the biodegradability of the carrier to intercept NH ₄ ⁺ -N (the carrier introduces pine sawdust to provide a carbon source for the biodegradation of NH ₄ ⁺ -N);

3) The present invention uses cement as the binder of the carrier to ensure the mechanical strength of the carrier, and uses industrial salt as the pore-forming agent to effectively ensure the porosity of the carrier and improve the contact surface between the carrier and the sewage.

Description of drawings

Fig. 1: is technique and technical route flowchart of the present invention.

Fig. 2: is the denitrification kinetics curve of the implementation effect of the carriers prepared in Example 1, Example 2, and Example 3 of the present invention.

Figure 3: is the phosphorus removal kinetics curve of the implementation effect of the carriers prepared in Example 1, Example 2, and Example 3 of the present invention.

Detailed ways

Example 1

A nitrogen and phosphorus removal carrier, the components by weight are as follows:

Based on the dry basis of the finished product as 200kg:

Clinoptilolite powder (90% through 100 mesh exchange capacity above 100cmol(+)/kg) 100kg

Gypsum powder (90% over 100 mesh) 70kg

Industrial table salt (particle size 2-3cm) 10kg

Ordinary Portland cement (label 425) 20kg

Pine sawdust 2kg

Add 200kg of clean water.

Prepare as follows:

1) According to the formula, mix clinoptilolite powder and gypsum powder with a powder mixer for 5-10 minutes to obtain material 1;

2) Under stirring conditions, add industrial salt, ordinary portland cement, and pine sawdust to material 1, and continue mixing, subject to the fact that there is no sign of unmixed material with the naked eye, to obtain material 2;

3) Spray the material 2 obtained in step 2) with clear water under stirring, and observe the plasticity of the material to obtain material 3;

4) The material 3 obtained in step 3) is made into a 3-5 cm spherical fresh carrier with an extrusion granulator;

5) submerging the fresh carrier obtained in step 4) with water, making the carrier pore-forming, and gradually hardening the cement in the carrier;

6) The carrier submerged in step 5) is stirred with water for 30 minutes every day, so that the compressive strength of the prepared carrier reaches 65-75N, and the carrier is drained for later use.

The nitrogen and phosphorus removal carrier prepared in this example has a first order reaction rate constant of 0.0188h ^-1 in the denitrification process and a half-life of 37h; a first order reaction rate constant of 0.1923h ^-1 in the phosphorus removal process and a half life of 4h.

Example 2

According to the preparation method of the embodiment, the present embodiment is another optimized formula wherein, the components by weight are as follows:

Clinoptilolite powder (90% over 100 mesh exchange capacity above 100cmol(+)/kg) 110kg

Gypsum powder (90% over 100 mesh) 60kg

Industrial table salt (particle size 2-3cm) 10kg

Ordinary Portland cement (label 325) 20kg

Pine sawdust 2kg

Add water 150kg.

The nitrogen and phosphorus removal carrier prepared in this example has a first order reaction rate constant of 0.0197h ^-1 in the denitrification process and a half-life of 35h; a first order reaction rate constant of 0.3395h ^-1 in the phosphorus removal process and a half life of 2h.

Example 3

The present embodiment is the best implementation mode of the present invention, according to the preparation method of embodiment, its formula by weight component is as follows:

Based on the dry basis of the finished product as 200kg:

Clinoptilolite powder (90% through 100 mesh exchange capacity above 100cmol(+)/kg) 120kg

Gypsum powder (90% over 100 mesh) 50kg

Industrial salt particle size (2-3cm) 10kg

Ordinary Portland cement (label 525) 20kg

Pine sawdust 2kg

Add water 100kg.

The nitrogen and phosphorus removal carrier prepared in this example has a first order reaction rate constant of 0.0205h ^-1 in the denitrification process and a half-life of 34h; a first order reaction rate constant of 0.2191h ^-1 in the phosphorus removal process and a half life of 3h.

According to the technical solutions and examples provided by the present invention, the nitrogen and phosphorus removal carrier of the present invention is generally prepared as a spherical carrier. When used, the carrier ball can be placed in the channel through which the sewage passes to form a so-called "biological corridor". To achieve the purpose of denitrification and dephosphorization of sewage. The carrier balls can also be packed in a mesh container and placed in a still water pond to achieve the same purpose of nitrogen and phosphorus removal.

Claims (5)

1. a denitrifying phosphorus-removing carrier is characterized in that, component by weight is as follows:

In the manufactured goods butt is 200kg:

Clinoptilolite powder (90% crosses 100 order exchange capacities at 100cmol (+)/more than the kg) 100～120kg

Land plaster (90% crosses 100 orders) 50～70kg

Industrial salt (particle diameter 2-3cm) 10kg

Portland cement (label 325-525) 20kg

Pine tree sawdust 2kg

Replenish clear water 100-200kg

Prepare according to the following step:

1) by prescription clinoptilolite powder and land plaster are mixed 5～10min with the powder mixer, obtain material 1;

2) under stirring condition, in material 1, add industrial salt, Portland cement, the pine tree sawdust continues to mix, and has not with the material that is invisible to the naked eye that the mixing sign is as the criterion, and obtains material 2;

3) with step 2) material 2 of gained under agitation sprays clear water, observes material and plasticity occurs and be as the criterion, and obtains material 3;

4) the material 3 usefulness Squeezinggranulators of step 3) gained are made the spherical fresh carrier of 3～5cm;

5) the fresh carrier water with the step 4) gained floods, and makes carrier pore-creating, and the interior cement of carrier is hardened gradually;

6) carrier and the water with the submergence of step 5) institute stirs 30min together every day, makes the carrier compression strength of preparation reach 65～75N, and it is standby to drain this carrier.

2. a kind of denitrifying phosphorus-removing carrier according to claim 1 is characterized in that, component by weight is as follows:

In the manufactured goods butt is 200kg:

Clinoptilolite powder (90% crosses 100 order exchange capacities at 100cmol (+)/more than the kg) 100kg

Land plaster (90% crosses 100 orders) 70kg

Industrial salt (particle diameter 2-3cm) 10kg

Portland cement (label 425) 20kg

Pine tree sawdust 2kg

Replenish clear water 200kg.

3. a kind of denitrifying phosphorus-removing carrier according to claim 1 is characterized in that, component by weight is as follows:

In the manufactured goods butt is 200kg:

Clinoptilolite powder (90% crosses 100 order exchange capacities at 100cmol (+)/more than the kg) 110kg

Land plaster (90% crosses 100 orders) 60kg

Industrial salt (particle diameter 2-3cm) 10kg

Portland cement (label 325) 20kg

Pine tree sawdust 2kg

Replenish clear water 150kg.

4. a kind of denitrifying phosphorus-removing carrier according to claim 1 is characterized in that, component by weight is as follows:

In the manufactured goods butt is 200kg:

Clinoptilolite powder (90% crosses 100 order exchange capacities at 100cmol (+)/more than the kg) 120kg

Land plaster (90% crosses 100 orders) 50kg

Industrial salt particle diameter 2-3cm) 10kg

Portland cement (label 525) 20kg

Pine tree sawdust 2kg

Replenish clear water 100kg.

5. the purposes of each described carrier of claim 1-4 in nitrogenous, phosphorous water environment.

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