CN110255784B - Method for synchronously removing nitrogen and phosphorus in pig-raising wastewater - Google Patents
Method for synchronously removing nitrogen and phosphorus in pig-raising wastewater Download PDFInfo
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Abstract
The invention relates to a method for synchronously removing nitrogen and phosphorus in pig wastewater. The method comprises the following steps: adding sodium chloride and natural ore powder into the pig raising wastewater, stirring and electrolyzing the sodium chloride, and standing to obtain a supernatant and a solid-liquid mixture from which nitrogen and phosphorus are removed; the mass concentration of sodium chloride in the pig raising wastewater is not lower than 2 g/L; the mass concentration of natural ore powder in the pig raising wastewater is not lower than 10 g/L. The method provided by the invention adopts the coupling process of electrolytic oxidation and chemical crystallization to achieve the purpose of synchronously removing nitrogen and phosphorus in the wastewater, has high removal efficiency and good removal effect, the removal rate of ammonia nitrogen can reach 99% or more, the removal rate of phosphorus can reach 88.7% or more, and the discharge standard can be reached. In addition, the method provided by the invention is simple to operate, does not need repeated pH adjustment, does not need to strictly add medicaments according to medicament proportion, and has the advantages of low price and easy acquisition of used raw materials and low wastewater treatment cost.
Description
Technical Field
The invention belongs to the technical field of environmental protection, and particularly relates to a method for synchronously removing nitrogen and phosphorus in pig wastewater.
Background
As a large amount of industrial, agricultural and domestic wastewater is discharged into water bodies, the water environment of China faces huge challenges. Meanwhile, water pollution and the harm caused by the water pollution aggravate the shortage of water resources, and the water pollution seriously threatens the life of people. Therefore, the research on the efficient and feasible water treatment technology is urgent.
As is known, nitrogen and phosphorus pollutants are discharged into rivers and lakes in large quantity, which is easy to cause eutrophication of water bodies, so that algae in the water bodies are propagated in large quantity, the dissolved oxygen content in the water is rapidly reduced, and the survival of aquatic organisms is influenced. Therefore, the comprehensive wastewater discharge standard of China strictly regulates the discharge concentration of pollutants such as nitrogen, phosphorus and the like, and places put forward more strict limiting conditions for the discharge of nitrogen and phosphorus pollutants in river basins.
Therefore, the amount of wastewater discharged by pig raising is large, and pollutants such as high-concentration nitrogen, phosphorus and the like in the wastewater cannot be effectively treated for a long time, so that the discharge of the pig raising wastewater becomes an important source of pollution of rivers and lakes. In addition, large amounts of contaminants such as nitrogen, phosphorus, etc. permeate into groundwater from surface runoff or from the soil, resulting in groundwater contamination. Therefore, how to efficiently treat the pig raising wastewater and reduce the discharge of nitrogen and phosphorus pollution is an important direction for treating the pig raising wastewater.
At present, the method for industrially treating nitrogen and phosphorus in wastewater mainly comprises a biological method and a chemical method. The biological denitrification technology is A/O, A2the/O, SBR oxidation ditch, etc. realize the decomposition and transformation process of nitrogen by obtaining energy from organic matters, but in the nitrification and denitrification processes, the biological treatment is strictly limited by various conditions such as pH, temperature, carbon source, dissolved oxygen, etc., so that the stable operation of the system can be ensured by strictly controlling the reaction conditions in practical application. The biological phosphorus removal technology is mainly characterized in that phosphorus is stored in a polymerized state in vivo through the anaerobic and aerobic states of phosphorus accumulating bacteria, and then is removed from a system in the form of sludge. The process has strict requirements on anaerobic and aerobic states, and the subsequent treatment of phosphorus in the sludge is one of the problems to be solved. The chemical denitrification technology mainly comprises a breakpoint chlorination method, an air stripping method, an adsorption method and the like. The breakpoint chlorine adding method needs to add a large amount of chlorine, and a large amount of substances harmful to human bodies are generated in the process; the air stripping method is generally used for treating high-concentration ammonia nitrogen wastewater, and has higher requirements on the temperature of the environment; the adsorption method generally adopts zeolite and the like as adsorbents and is generally used for treating low-concentration ammonia nitrogen wastewater, a large amount of sludge is generated in the reaction process, and the effect is not good in practical application. The chemical phosphorus removal technology is mainly characterized in that a flocculating agent is added into the wastewater to react with phosphate in the wastewater to generate precipitate, a large amount of chemical agents are required to be added in the reaction, and the treatment cost is high. In industrial application, the traditional nitrogen and phosphorus removal method is difficult to meet the practical requirements. The electrolytic method has the advantages of high efficiency, simple equipment, low treatment cost and the like, and is more and more widely concerned in practical application.
The pig-raising wastewater contains high-concentration pollutants such as nitrogen, phosphorus and the like, only a traditional electrolysis method is adopted, the treatment efficiency is low, and the removal effect does not reach the standard of discharge requirements. Therefore, the development of a new electrolysis method for improving the removal efficiency of nitrogen and phosphorus pollutants in the pig raising wastewater in the electrolysis process has important research significance and environmental protection application value.
Disclosure of Invention
The invention aims to overcome the defects and shortcomings that the removal efficiency of nitrogen and phosphorus pollutants in the pig-raising wastewater treated by the existing electrolytic method is low and cannot reach the discharge standard, and provides a method for synchronously removing nitrogen and phosphorus in the pig-raising wastewater. The method provided by the invention adopts the coupling process of electrolytic oxidation and chemical crystallization to achieve the purpose of synchronously removing nitrogen and phosphorus in the wastewater, has high removal efficiency and good removal effect, the removal rate of ammonia nitrogen can reach more than 99%, the removal rate of phosphorus can reach 88.7% and more, and the discharge standard can be reached. In addition, the method provided by the invention is simple to operate, does not need repeated pH adjustment, does not need to strictly add medicaments according to medicament proportion, and has the advantages of low price and easy acquisition of used raw materials and low wastewater treatment cost.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for synchronously removing nitrogen and phosphorus in pig wastewater comprises the following steps: adding sodium chloride and natural ore powder into the pig raising wastewater, stirring and electrolyzing the sodium chloride, and standing to obtain a supernatant and a solid-liquid mixture from which nitrogen and phosphorus are removed; the mass concentration of chlorine salt in the pig raising wastewater is not lower than 2 g/L; the mass concentration of natural ore powder in the pig raising wastewater is not lower than 10 g/L.
During electrolysis, the following reactions occur:
anode: 2Cl––2e–→Cl2↑
Cathode: 2H++2e–→H2↑
Cl liberated2Has strong oxidizability, and can oxidize ammonia nitrogen in the wastewater into N2The acid is generated at the same time as the removal, so that the pH value of the solution is reduced.
The natural ore powder in the aqueous solution system mainly contains CaCO3(some also include MgCO3) The acid produced can make Ca in the natural ore powder2+、Mg2+Dissolving out the Ca2+、Mg2+Can generate precipitate with phosphate in the wastewater so as to achieve the aim of removing phosphorus.
The method realizes synchronous removal of nitrogen and phosphorus in the pig-raising wastewater by controlling the electrolysis amount and the natural ore powder amount, has high removal efficiency and good removal effect, the removal rate of ammonia nitrogen can reach 99% or more, the removal rate of phosphorus can reach 88.7% or more, and the discharge standard can be reached. In addition, the method provided by the invention is simple to operate, does not need repeated pH adjustment, does not need to strictly add medicaments according to medicament proportion, and has the advantages of low price and easy acquisition of used raw materials and low wastewater treatment cost.
The electrolysis process in the invention is a conventional electrolysis process, and the selection of a power supply, electrodes and voltage can be carried out according to conventional conditions.
Preferably, the electrolysis process is to electrolyze the electrode by using a direct current power supply.
More preferably, the electrode positive electrode and the electrode negative electrode are inert electrodes.
Inert electrodes conventional in the art may be used in the present invention, such as platinum electrodes, gold electrodes, carbon electrodes, and the like.
Preferably, the inert electrode is a graphite electrode.
Preferably, the voltage of the electrolysis is 20-30V.
Preferably, the electrolysis time is 150-250 min.
Cl produced electrolytically under such conditions2The ammonia nitrogen can be oxidized as much as possible under the condition of saving cost.
Preferably, the standing time is 60-120 min.
Preferably, the mass concentration of the chlorine salt in the pig raising wastewater is 2-10 g/L.
Preferably, the chloride salt is one or more of sodium chloride or potassium chloride.
Preferably, the mass concentration of the natural ore powder in the pig raising wastewater is 10-30 g/L.
Preferably, the natural ore powder is one or more of dolomite powder or limestone powder.
The dolomite powder mainly comprises CaCO3And MgCO3The main component of limestone powder is CaCO3Can provide sufficient Ca2+、Mg2+。
Generally, the mass concentration of nitrogen in the pig raising wastewater is 200-1200 mg/L in terms of NH4Calculated by-N, the mass concentration of phosphorus is 20-150 mg/L in terms of PO4-P meter, all suitable for treatment with the process of the invention.
Preferably, the mass concentration of nitrogen in the pig raising wastewater is 200-1200 g/L, and NH is used4-N counts; the mass concentration of phosphorus in the pig raising wastewater is 20-150 g/L, and PO is used4-a P meter.
Compared with the prior art, the invention has the following beneficial effects:
the method provided by the invention adopts the coupling process of electrolytic oxidation and chemical crystallization to achieve the purpose of synchronously removing nitrogen and phosphorus in the wastewater, has high removal efficiency and good removal effect, the removal rate of ammonia nitrogen can reach 99% or more, the removal rate of phosphorus can reach 88.7% or more, and the discharge standard can be reached. In addition, the method provided by the invention is simple to operate, does not need repeated pH adjustment, does not need to strictly add medicaments according to medicament proportion, and has the advantages of low price and easy acquisition of used raw materials and low wastewater treatment cost.
Drawings
FIG. 1 is a schematic flow diagram of an apparatus according to the present invention; wherein 1 is an electrolytic reactor, 2 is a solid-liquid discharge port, 3 is a stirrer, 4 is a direct current power supply, 5 is a wastewater discharge port, and 6 is an electrolytic electrode.
Detailed Description
The invention is further illustrated by the following examples. These examples are intended to illustrate the invention and are not intended to limit the scope of the invention. Experimental procedures without specific conditions noted in the examples below, generally according to conditions conventional in the art or as suggested by the manufacturer; the raw materials, reagents and the like used are, unless otherwise specified, those commercially available from the conventional markets and the like. Any insubstantial changes and substitutions made by those skilled in the art based on the present invention are intended to be covered by the claims.
Example 1
The embodiment provides a method for synchronously removing nitrogen and phosphorus in pig wastewater, which utilizes the device shown in fig. 1 to perform treatment, and the specific operations are as follows.
First, 1m of the solution was charged into an electrolytic reactor 13The pig raising wastewater with ammonia nitrogen and phosphorus concentrations of 523mg/L and 90mg/L respectively is added with dolomite powder according to 10g/L, then sodium chloride is added according to 2g/L, a stirrer is started, a direct current power supply 4 is switched on to supply power for an electrolysis electrode 6 (a graphite electrode, the same below) at the same time, the stirring electrolysis time is controlled to be 150min, the electrolysis voltage is controlled to be 20V, the stirrer 3 and the direct current power supply 4 are closed after the reaction is finished, the solution is kept stand for 60min, the supernatant is discharged from a wastewater discharge port 5, and the solid-liquid mixture is discharged from a solid-liquid discharge port 2.
Through the operation steps, the ammonia nitrogen concentration in the pig raising wastewater is reduced to 5mg/L, the ammonia nitrogen removal rate is 99%, the phosphorus concentration is reduced to 10mg/L, and the phosphorus recovery rate is 88.7%.
Example 2
The embodiment provides a method for synchronously removing nitrogen and phosphorus in pig wastewater, which comprises the following specific operations.
First, 1m of the solution was charged into an electrolytic reactor 13The pig raising wastewater with ammonia nitrogen and phosphorus concentrations of 523mg/L and 90mg/L respectively is added with limestone powder according to 20g/L, sodium chloride is added according to 8g/L, the stirrer 3 is started, the direct current power supply 4 is switched on to supply power for the electrolysis electrode 6, the stirring electrolysis time is controlled to be 200min, the electrolysis voltage is controlled to be 25V, the stirrer 3 and the direct current power supply 4 are closed after the reaction is finished, the solution is kept stand for 100min, the supernatant is discharged from the wastewater discharge port 5, and the solid-liquid mixture is discharged from the solid-liquid discharge port 2.
Through the operation steps, the ammonia nitrogen concentration in the pig raising wastewater is reduced to 4mg/L, the ammonia nitrogen removal rate is 99.3%, the phosphorus concentration is reduced to 8mg/L, and the phosphorus recovery rate is 91.1%.
Example 3
The embodiment provides a method for synchronously removing nitrogen and phosphorus in pig wastewater, which comprises the following specific operations.
First, 1m of the solution was charged into an electrolytic reactor 13Adding dolomite powder and limestone powder mixture (the mass ratio is 1: 1) according to the concentration of 30g/L, adding sodium chloride according to the concentration of 10g/L, starting a stirrer 3, simultaneously switching on a direct current power supply 4 to supply power to an electrolysis electrode 6, controlling the stirring electrolysis time to be 250min, controlling the electrolysis voltage to be 30V, closing the stirrer 3 and the direct current power supply 4 after the reaction is finished, standing the solution for 120min, discharging supernatant from a wastewater discharge port 5, and discharging solid-liquid mixture from a solid-liquid discharge port 2.
Through the operation steps, the ammonia nitrogen concentration in the pig raising wastewater is reduced to 2mg/L, the ammonia nitrogen removal rate is 99.6%, the phosphorus concentration is reduced to 5mg/L, and the phosphorus recovery rate is 94.4%.
It will be appreciated by those of ordinary skill in the art that the examples provided herein are intended to assist the reader in understanding the principles of the invention and are to be construed as being without limitation to such specifically recited examples and embodiments. Those skilled in the art can make various other specific changes and combinations based on the teachings of the present invention without departing from the spirit of the invention, and these changes and combinations are within the scope of the invention.
Claims (6)
1. A method for synchronously removing nitrogen and phosphorus in pig wastewater is characterized by comprising the following steps: adding chloride salt and natural ore powder into the pig raising wastewater, stirring, electrolyzing, and standing to obtain a supernatant and a solid-liquid mixture from which nitrogen and phosphorus are removed; the mass concentration of chlorine salt in the pig raising wastewater is not lower than 2 g/L; the mass concentration of natural ore powder in the pig raising wastewater is not lower than 10 g/L;
the electrolysis process is to electrolyze the electrode by using a direct current power supply; the anode and the cathode of the electrode are inert electrodes;
the natural ore powder is one or more of dolomite powder or limestone powder.
2. The method according to claim 1, wherein the voltage of the electrolysis is 20-30V; the electrolysis time is 150-250 min.
3. The method according to claim 1, wherein the standing time is 60-120 min.
4. The method according to claim 1, wherein the mass concentration of the chlorine salt in the pig wastewater is 2-10 g/L.
5. The method of claim 1, wherein the chloride salt is one or more of sodium chloride or potassium chloride.
6. The method according to claim 1, wherein the mass concentration of the natural ore powder in the pig wastewater is 10-30 g/L.
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| CN105110523A (en) * | 2015-09-11 | 2015-12-02 | 燕山大学 | Method for treating swine wastewater |
| CN108977823A (en) * | 2018-08-30 | 2018-12-11 | 湖北美辰环保科技有限公司 | A kind of nitrogen phosphorus fluorine recovery method based on electrochemical reactor |
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| CN105110523A (en) * | 2015-09-11 | 2015-12-02 | 燕山大学 | Method for treating swine wastewater |
| CN108977823A (en) * | 2018-08-30 | 2018-12-11 | 湖北美辰环保科技有限公司 | A kind of nitrogen phosphorus fluorine recovery method based on electrochemical reactor |
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