College chemical laboratory wastewater treatment process design method

Abstract

The invention discloses a college chemical laboratory wastewater treatment process design method. The method comprises the following steps: S1, wastewater pretreatment; s2, central wastewater treatment; s3, then entering an AAO (anaerobic-anoxic-oxic) wastewater treatment stage; s4, after treatment, entering an aerobic tank; s5, in the wastewater treatment according to the step 1, metal ions and other inorganic ions in the wastewater are converted into waste residue precipitates after being treated, and the waste residue precipitates are separated by a filter screen; and S6, collecting the precipitates in a centralized manner, separating and recycling the precipitates by using separation equipment, and carrying out classified refining treatment on the chemical laboratory wastewater by using a precipitation method, an adsorption method, an ozone oxidation method and the like so as to achieve the purpose of reducing pollution. According to the design, water reaching the standard after treatment is recycled for greening irrigation or cleaning use, and precious metal generated in the water treatment process is recycled, so that the purposes of resource circulation and recycling are achieved. In conclusion, the design can play a certain role in the aspects of water pollution treatment, resource recycling and the like and the aspect of low-carbon campus construction.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a wastewater treatment process design method for a chemistry laboratory in a university. Background Art

[0002] With the continuous expansion of colleges and universities and the rapid development of the economy, the number of students has increased sharply, and the number of scientific research experiments has increased. The amount of laboratory wastewater is also increasing day by day, and the discharge cycle is uncertain and the water quality composition is complex. The wastewater contains not only organic matter such as detergents and common solvents, but also contains a large amount of acids, alkalis, heavy metals and toxic and harmful substances, and is accompanied by many new substances, and the properties are difficult to determine. Most of the laboratory wastewater in teaching and scientific research units in my country is not properly treated and is directly discharged. The chemistry laboratories in universities include inorganic chemistry laboratories, organic chemistry laboratories, analytical chemistry laboratories, physical chemistry laboratories, inorganic and analytical chemistry laboratories, etc. The laboratory is mainly based on teaching and scientific research, and undertakes the experimental part of professional experimental courses and public courses, as well as the scientific research projects of full-time teachers. Judging from the above situation, laboratory wastewater is mainly acid-base wastewater, organic wastewater, inorganic wastewater, and comprehensive wastewater. According to previous course arrangements and scientific research project statistics, about 3,000L of wastewater is generated each year, which will cause serious pollution to the surrounding river water bodies. Summary of the invention

[0003] The purpose of the present invention is to provide a method for designing a wastewater treatment process for a chemistry laboratory in a university, so as to solve the problems raised in the above-mentioned background technology.

[0004] To achieve the above object, the present invention provides the following technical solution: a method for designing a wastewater treatment process for a university chemistry laboratory, comprising the following steps:

[0005] S1. Wastewater pretreatment: Organic and inorganic wastewater are pretreated before entering the central wastewater treatment device;

[0006] S2. Central wastewater treatment: When the central treatment tank is full, the wastewater enters the pH adjustment tank. After the pH value is adjusted, it is sent to the oxidation tank, where O3 is added for full oxidation. Then, it passes through the activated carbon filter to adsorb the oxidation decomposition products.

[0007] S3. Then it enters the AAO wastewater treatment stage. The wastewater first enters the anaerobic tank, which contains phosphorus-releasing bacteria, which release phosphorus and ammonify some organic matter. Then it flows into the anoxic tank, which denitrifies the nitrate nitrogen sent from the aerobic tank through internal circulation.

[0008] S4. After treatment, it enters the aerobic pool, where BOD is removed, nitrification and phosphorus absorption are also carried out, and the wastewater that does not meet the standards and the return sludge return to the anaerobic pool, and the wastewater that meets the standards proceeds to the next step. After being treated by the AAO process, the wastewater flows into the disinfection pool, which has ultraviolet lamps and disinfectants that can effectively kill bacteria and viruses. The treated wastewater meets the standards and can be discharged;

[0009] S5. In the wastewater treatment according to step 1, the metal ions and other inorganic ions in the wastewater are treated and converted into waste residues which enter the sedimentation tank for precipitation and are separated by the filter screen, and the ions in the metal waste residues are recycled and the waste residues are recycled by wet recovery method, flotation or microbial leaching method;

[0010] S6. The metal ion compound precipitates separated in the sedimentation tank are collected and recovered by separation equipment. The collected and recovered glass fragments are washed and sent to a recycling waste treatment station for recycling.

[0011] Preferably, the wet recovery method includes an acid leaching method and an alkaline leaching method, the leaching agent in the acid leaching method is sulfuric acid, and the leaching agent in the alkaline leaching method is aqueous ammonia.

[0012] Preferably, the flotation method utilizes the difference in hydrophobicity and hydrophilicity of the surfaces of particles of different components in the waste slag to distinguish them, and the valuable metal waste slag sinks for separation.

[0013] Preferably, the microbial leaching method utilizes the oxidizing and reducing properties of microorganisms to oxidize and reduce the usable components in the waste residue, and separates the usable components in the waste residue in the form of ions or precipitation.

[0014] Preferably, after the organic wastewater is generated and discharged from the laboratory, it is passed through a grid to screen out large wastes and the filtered wastewater is filtered for a second time through a filter and temporarily stored in an organic wastewater tank. The wastewater passes through an activated carbon filter and enters a degradation tank for degradation and is allowed to stand for a period of time. The flocculants are filtered out through another filter and finally enter the central wastewater treatment tank.

[0015] Preferably, the inorganic wastewater passes through a grid and a filter screen and enters an inorganic wastewater tank, where the pH value is adjusted in a pH adjustment tank and flows into a sedimentation tank to add reagents, and undergoes two precipitations to remove cadmium, iron, cobalt, manganese and other ions.

[0016] Preferably, the inorganic wastewater is precipitated twice, passes through a fly ash filter, flows into a central wastewater treatment tank, passes through a grid and a filter, is temporarily stored in a comprehensive wastewater tank, and is discharged into the central wastewater treatment tank.

[0017] Compared with the prior art, the technical effects and advantages of the present invention are as follows: the wastewater treatment process design method of the chemical laboratory of the university uses precipitation method, adsorption method, ozone oxidation method, etc. to classify and refine the chemical laboratory wastewater to achieve the purpose of reducing pollution. This design recycles the water that meets the standards after treatment for greening irrigation or cleaning, and recycles the precious metals generated during the water treatment process to achieve the purpose of resource circulation and recycling. In summary, this design can play a certain role in the construction of a low-carbon campus in terms of water pollution treatment, resource recycling, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a process flow chart of the wastewater pretreatment stage of the present invention;

[0019] Figure 2 It is a process flow chart of the central processing stage of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] See also Figure 1-2 The present invention provides a technical solution: a method for designing a wastewater treatment process for a university chemistry laboratory, comprising the following steps:

[0022] S1. Wastewater pretreatment: Organic and inorganic wastewater are pretreated before entering the central wastewater treatment device;

[0023] S2. Central wastewater treatment: When the central treatment tank is full, the wastewater enters the pH adjustment tank. After the pH value is adjusted, it is sent to the oxidation tank, where O3 is added for full oxidation. Then, it passes through the activated carbon filter to adsorb the oxidation decomposition products.

[0024] S3. Then it enters the AAO wastewater treatment stage. The wastewater first enters the anaerobic tank, which contains phosphorus-releasing bacteria, which release phosphorus and ammonify some organic matter. Then it flows into the anoxic tank, which denitrifies the nitrate nitrogen sent from the aerobic tank through internal circulation.

[0025] S4. After treatment, it enters the aerobic pool, where BOD is removed, nitrification and phosphorus absorption are also carried out, and the wastewater that does not meet the standards and the return sludge return to the anaerobic pool, and the wastewater that meets the standards proceeds to the next step. After being treated by the AAO process, the wastewater flows into the disinfection pool, which has ultraviolet lamps and disinfectants that can effectively kill bacteria and viruses. The treated wastewater meets the standards and can be discharged;

[0026] S5. In the wastewater treatment according to step 1, the metal ions and other inorganic ions in the wastewater are treated and converted into waste residues which enter the sedimentation tank for precipitation and are separated by the filter screen, and the ions in the metal waste residues are recycled and the waste residues are recycled by wet recovery method, flotation or microbial leaching method;

[0027] S6. The metal ion compound precipitates separated in the sedimentation tank are collected and recovered by separation equipment. The collected and recovered glass fragments are washed and sent to a recyclable waste treatment station for recycling.

[0028] The wet recovery method includes acid leaching and alkaline leaching. The leaching agent in the acid leaching method is sulfuric acid, and the leaching agent in the alkaline leaching method is ammonia water. The acid leaching method is widely used in actual processes and has good selectivity for metals such as zinc, cobalt, and nickel. Sulfuric acid is mostly selected as the leaching agent; while the alkaline leaching method has good selectivity for iron and chromium. Ammonia water is mostly selected as the leaching agent. After the leachate is extracted, it is recovered using ion exchange, extraction and other technologies.

[0029] The flotation method uses the difference in hydrophobicity and hydrophilicity of the surface of particles of different components in the waste slag to distinguish the valuable metal waste slag from the surface.

[0030] The flotation method uses the difference in hydrophobicity and hydrophilicity of the surface of particles of different components in the waste slag to distinguish, and the valuable metal waste slag sinks for separation. The microbial leaching method uses the oxidizing and reducing properties of microorganisms to oxidize and reduce the usable components in the waste slag, and separate the usable components in the waste slag in the form of ions or precipitation.

[0031] The microbial leaching method utilizes the oxidizing and reducing properties of microorganisms to oxidize and reduce the usable components in the waste residue, and separates the usable components in the waste residue in the form of ions or precipitation.

[0032] After the organic wastewater is generated and discharged from the laboratory, it passes through a grid to screen out large wastes and the filtered wastewater is filtered for a second time through a filter and temporarily stored in an organic wastewater tank. The wastewater passes through an activated carbon filter and enters a degradation tank for degradation and is allowed to stand for a period of time. The flocculants are filtered out through another filter and finally enter the central wastewater treatment tank.

[0033] The laboratory wastewater first flows into the regulating sedimentation tank I through a fine screen (3mm), and the effluent enters the oil stripping tower; the surfactant and demulsifier are added to the oil stripping tower through a dosing device, and the separated gas and oil are ignited; the effluent is treated by a wet oxidation process; flocculants, calcium oxide, sodium sulfide and other substances are mixed with the wet oxidation effluent and enter the sedimentation tank, the effluent is physically and chemically treated, and flows into the regulating sedimentation tank II of the biochemical system; the wastewater from the teaching building and living area flows into the regulating sedimentation tank II through a 10mm fine screen, mixed with the physically and chemically treated water, and then passed through A 2 / O process removes nitrogen, phosphorus and BOD; finally, the substances that have not been removed from the water are removed by pressure filter tanks, and the sludge and sediment generated in the whole process are dehydrated and landfilled

[0034] The inorganic wastewater passes through the screen and the filter and enters the inorganic wastewater tank, where the pH value is adjusted in the pH adjustment tank and flows into the sedimentation tank to add reagents. Two precipitations are performed to remove cadmium, iron, cobalt, manganese and other ions. The function of the screen is to remove larger suspended or floating objects in the sewage to reduce the processing load of subsequent water treatment processes, and to protect water pumps, pipes, instruments, etc. It is an essential component of sewage treatment.

[0035] The regulating sedimentation tank is a combination of a regulating tank, a neutralization tank and a primary sedimentation tank. The combination of the three tanks has the effect of saving floor space. The regulating sedimentation tank plays the role of regulating water volume (internal line regulation), regulating water quality and precipitating solids. It is shaped like a vertical flow sedimentation tank, but the liquid storage volume is larger. The volume of the physical and chemical part is smaller than that of the biochemical part (due to the different water volume). The regulating tank and the primary sedimentation tank are necessary components for wastewater treatment. After the inorganic wastewater is precipitated twice, it passes through the fly ash filter and flows into the central wastewater treatment tank. After passing through the grille and filter, it is temporarily stored in the comprehensive wastewater tank and discharged into the central wastewater treatment tank.

[0036] The sedimentation tank adopts the horizontal flow inclined plate inclined tube type, which occupies less space, has higher efficiency and shorter residence time. The addition of flocculants, calcium oxide and sodium sulfide precipitates heavy metals and other substances.

[0037] In practice, the power source for the above process can be provided by a pump. Due to the complex quality of wastewater, it is recommended to use a vacuum pump. 2 / O produced sludge and sediment can be safely landfilled after PAM dehydration and filter press dehydration. The wastewater treated by this process meets the national emission standards. Studies have shown that wetlands effectively treat low-concentration wastewater. Most colleges and universities build artificial wetlands. Southern colleges and universities do not use pressure filters, but directly discharge to artificial wetlands. Northern colleges and universities only use pressure filters in winter, or open pressure filters when emissions do not meet standards, to achieve energy saving.

[0038] Adhering to the concept of green and environmental protection, there are many ways to treat wastewater that meets the standards. First of all, as irrigation water for university gardens, it can greatly reduce the amount of water used in gardens. It can also be used to supply water to toilets or as cleaning water through recycling pipelines. After centralized storage, it can also be connected to the municipal water supply system for unified municipal management. The metal ion compound precipitation separated in the sedimentation tank has a high recycling significance. The precipitation can be collected and handed over to professional chemical companies for separation and recycling. The collected and recycled glass slag can be sent to the recyclable garbage treatment station for recycling after cleaning.

[0039] Specifically, when used, the process flow of laboratory wastewater treatment was designed according to the water volume and water quality of laboratory wastewater from a petroleum university. First, it flows into the regulating sedimentation tank I through the fine grid, and the effluent passes through the blow-off oil separator (the separated gas and oil are ignited). The treated water is treated by the wet oxidation process, and finally the non-chemical treatment process is completed through the sedimentation tank. The physical and chemical treatment wastewater is mixed with domestic water and passed through A 2 The / O process removes nitrogen and phosphorus and reduces BOD, and finally removes untreatable substances in the water through a pressure filter tank. The sludge and sediment generated in the whole process are dehydrated and landfilled sanitarily.

[0040] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for designing wastewater treatment process for chemical laboratories in universities, characterized by: The steps include: S1. Wastewater pretreatment: Organic and inorganic wastewater are pretreated before entering the central wastewater treatment device; S2. Central wastewater treatment: When the central treatment tank is full, the wastewater enters the pH adjustment tank. After the pH value is adjusted, it is sent to the oxidation tank, where O3 is added for full oxidation. Then, it passes through the activated carbon filter to adsorb the oxidation decomposition products. S3. Then it enters the AAO wastewater treatment stage. The wastewater first enters the anaerobic tank, which contains phosphorus-releasing bacteria, which release phosphorus and ammonify some organic matter. Then it flows into the anoxic tank, which denitrifies the nitrate nitrogen sent from the aerobic tank through internal circulation. S4. After treatment, it enters the aerobic pool, where BOD is removed, nitrification and phosphorus absorption are also carried out, and the wastewater that does not meet the standards and the return sludge return to the anaerobic pool, and the wastewater that meets the standards proceeds to the next step. After being treated by the AAO process, the wastewater flows into the disinfection pool, which has ultraviolet lamps and disinfectants that can effectively kill bacteria and viruses. The treated wastewater meets the discharge standards; S5. In the wastewater treatment according to step 1, the metal ions and other inorganic ions in the wastewater are treated and converted into waste residues which enter the sedimentation tank for precipitation and are separated by the filter screen, and the ions in the metal waste residues are recycled and the waste residues are recycled by wet recovery method, flotation or microbial leaching method; S6. The metal ion compound precipitates separated in the sedimentation tank are collected and recovered by separation equipment. The collected and recovered glass fragments are washed and sent to a recyclable waste treatment station for recycling.

2. A method for designing wastewater treatment process for a university chemistry laboratory according to claim 1, characterized in that: The wet recovery method includes an acid leaching method and an alkaline leaching method. The leaching agent in the acid leaching method is sulfuric acid, and the leaching agent in the alkaline leaching method is ammonia water.

3. A method for designing wastewater treatment process for a university chemistry laboratory according to claim 1, characterized in that: The flotation method utilizes the difference between the hydrophobicity and hydrophilicity of the surfaces of particles of different components in the waste slag to distinguish them, and the valuable metal waste slag sinks to be separated.

4. A method for designing wastewater treatment process for a university chemistry laboratory according to claim 1, characterized in that: The microbial leaching method utilizes the oxidizing and reducing properties of microorganisms to oxidize and reduce the usable components in the waste residue, and separates the usable components in the waste residue in the form of ions or precipitation.

5. A method for designing wastewater treatment process for a university chemistry laboratory according to claim 1, characterized in that: After the organic wastewater is generated and discharged from the laboratory, it passes through a grid to screen out large wastes and the filtered wastewater is filtered for a second time through a filter and temporarily stored in an organic wastewater tank. The wastewater passes through an activated carbon filter and enters a degradation tank for degradation and is allowed to stand for a period of time. The flocculants are filtered out through another filter and finally enter the central wastewater treatment tank.

6. A method for designing wastewater treatment process for a university chemistry laboratory according to claim 1, characterized in that: The inorganic wastewater passes through the grid and the filter screen and enters the inorganic wastewater tank, where the pH value is adjusted in the pH adjustment tank and then flows into the sedimentation tank where reagents are added, and undergoes two precipitations to remove cadmium, iron, cobalt and manganese.

7. A wastewater treatment process design method for university chemistry laboratories according to claim 1, characterized in that: After two sedimentations, the inorganic wastewater passes through the fly ash filter and flows into the central wastewater treatment tank, passes through the grid and filter, and is temporarily stored in the comprehensive wastewater tank and discharged into the central wastewater treatment tank.

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