Wastewater treatment methods are to use physical, chemical and biological methods to treat wastewater, so as to purify wastewater, reduce pollution, so as to achieve wastewater recovery, reuse and make full use of water resources.
Domestic sewage refers to the waste water discharged from people's daily life activities. This waste water is mainly polluted by domestic waste and human excreta. The quantity, composition and concentration of pollutants are related to people's living habits and water consumption.Domestic sewage generally does not contain toxic substances, but it has conditions suitable for microbial reproduction, contains a large number of bacteria and pathogens, and is harmful from the perspective of sanitation.[1]
Due to the increasing urban population, the problem of urban domestic wastewater treatment has become increasingly prominent.And because of backward technology, shortage of funds and difficulty in governance, it has always affected the urban environment and its construction.If these problems are not solved as soon as possible, the pollution will be more serious and the impact will be worse with the progress of urbanization and the continuous increase of water consumption.[2]
Unlike industrial wastewater, urban domestic sewage can be stopped or industrial enterprises can be relocated to solve the problem at the source.Urban domestic sewage mainly comes from a series of urban public places and utilities such as families, schools and businesses.The universality and inevitability of its source also make the sewage treatment face a regional tendency.The pollutants of urban domestic sewage are more diverse, but their main content is mainly organic matter, in which starch, protein, sugar, mineral oil and other domestic wastes are the majority, of which,BODtwo(Biological oxygen demand), CODc2（Chemical oxygen demand）、TkN（Kjeldahl nitrogen）、TP（Total phosphorus）、TN（Total nitrogen）It is also high. It is easy to cause eutrophication of the water body after being discharged into the water body, which makes algae grow and multiply in large quantities. The red tide and water bloom we usually see are related to this.However, due to seasonal temperature and the death of algae metabolism, the water body will become rotten, smelly, and the water quality will deteriorate, which will also make the performance characteristics and the content of specific components of urban domestic sewage, and also make us have a clearer understanding of each link when dealing with urban domestic sewage.[3]
We all know that water is the source of life, and our country is also a country with relatively poor freshwater resources. Saving urban domestic water is like saving our lives. Time waits for no man![3]
industrial waste water
Industrial production will produce many kinds of pollutants, and the types and concentrations of pollutants produced by different industries are significantly different.[4]
Electroplating wastewater
The main source of zinc in electroplating and metal processing wastewater is the towing solution for electroplating or pickling.The pollutants are transferred to the rinsing water through the metal rinsing process.The pickling process includes first immersing the metal (zinc or copper) in strong acid to remove the oxide on the surface, and then immersing it in the brightener containing strong chromic acid for polishing.
The wastewater contains a large amount of hydrochloric acid, zinc, copper and other heavy metal ions and organic brighteners, which are highly toxic. Some of them also contain carcinogenic, teratogenic and mutagenic highly toxic substances, which are extremely harmful to human beings.Therefore, electroplating wastewater must be seriously recycled to eliminate or reduce its environmental pollution.
Electroplating wastewater treatmentThe iron chip internal electrolysis treatment process is adopted, which mainly uses activated industrial iron chip to purify the wastewater. When the wastewater contacts with the filler, electrochemical reaction, chemical reaction and physical action will occur, including catalysis, oxidation, reduction, replacement, co precipitation, flocculation, adsorption and other comprehensive actions, to remove various metal ions in the wastewater, so that the wastewater can be purified.
Heavy metal wastewater
The heavy metal wastewater mainly comes from the wastewater discharged from mining, smelting, electrolysis, electroplating, pesticide, medicine, paint, pigment and other enterprises.If heavy metal wastewater is not treated, it will be seriousenvironment pollution。The types, contents and existing forms of heavy metals in wastewater treatment vary with different production enterprises.Heavy metal removal is very important in wastewater treatment.
Because heavy metals cannot be decomposed and destroyed, they can only transfer their existing position and change their physical and chemical forms to achieve the purpose of removing heavy metals.For example, during wastewater treatmentchemical precipitation After treatment, the heavy metals in the wastewater change from dissolved ionic form toInsoluble compoundsThe sediment is transferred from water to sludge;After ion exchange treatment, heavy metal ions in wastewater are transferred toion exchange resinAfter regeneration, it is transferred from the ion exchange resin to the regenerated waste liquid.
Therefore, the principle of heavy metal removal in wastewater treatment is:
Principle 1 of heavy metal removal: the most fundamental is to reform the production process. Do not use or use less toxic heavy metals;
Principle 2 of heavy metal removal: adopt reasonable process flow, scientific management and operation, reduce heavy metal consumption and loss with waste water flow, and try to reduce the amount of discharged waste water.The treatment of heavy metal wastewater should be carried out on the spot at the place where it is produced and mixed with other wastewater to avoid complicating the treatment.It should not be directly discharged into the city without removing heavy metalssewerTo avoid expanding heavy metal pollution.
The methods of removing heavy metals from wastewater treatment can generally be divided into two categories:
Method I of heavy metal removal: make the dissolved heavy metals in wastewater become insolubleMetal compoundOr element, which can be removed from wastewater by sedimentation and floatation. Applicable methods include neutralization sedimentation method, sulfide precipitation method, floatation separation method, electrolytic precipitation (or floatation) methodDiaphragm electrolysisAnd other wastewater treatment methods;
Method 2 of heavy metal removal: concentration and separation of heavy metals in wastewater without changing their chemical forms. The applicable methods areReverse osmosis method, electrodialysis, evaporation, ion exchange, etc.These wastewater treatment methods shall be used separately or in combination according to wastewater quality, quantity, etc.
processing method
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Physical treatment
The methods of separating and recovering insoluble suspended pollutants (including oil film and oil droplet) in wastewater by physical action can be divided into gravity separation method, centrifugal separation method and sieve filtration interception method.The treatment units of gravity separation method include sedimentation, flotation (air flotation), etc. The corresponding treatment equipment is grit chamber, sedimentation tank, oil separator, air flotation tank and its auxiliary devices.The centrifugal separation method itself is a processing unit, and the processing devices used areCentrifugal separatorAnd water cyclone separator, etc.The screen filtration interception method has two processing units: screen filtration and filtration. The former uses grid and screen, while the latter uses sand filter and microporous filter.The treatment method based on the heat exchange principle also belongs to the physical treatment method, and its treatment units include evaporation, crystallization, etc.
A method for removing organic matter from wastewater isActivated carbon adsorption method。Activated carbon treatment can be used together with activated sludge processPowdered activated carbon。Powdered activated carbon can absorb those substances that are toxic to microorganisms, and finally collect them together with sludge.The main danger of activated carbon method in sewage treatment process is that invalid activated carbon may always exist in water.[5]
Chemical treatment
adoptchemical reactionAnd mass transfercolloidState pollutants or waste water treatment method that converts them into harmless substances.stayChemical treatmentThe treatment unit based on chemical reaction generated by adding chemicals is:Coagulation, neutralization, redox, etc;The treatment units based on mass transfer include: extractionStripping, blowing off, adsorption, ion exchange andElectrodialysisandreverse osmosisEtc.The latter two processing units are also collectively calledMembrane separation technology。The treatment unit using mass transfer has both chemical and related physical effects, so it can also be separated from chemical treatment method and become another type of treatment method, called physical-chemical method.
Biological treatment
Microbialmetabolism, which makes the waste water in the state of solution, colloid and fine suspensionOrganic pollutants, which is converted into stable and harmless substances.According to the different microorganisms,Biological treatmentIt can also be divided into aerobic biological treatment andAnaerobic biological treatmentTwo types.
useBiological contact oxidation methodWastewater treatment, ready for useBiological contact oxidationThe process is filled with fillers in the biological reaction tank, and the oxygenatedsewageImmerse all the filler and flow through the filler at a certain flow rate.The filler is covered with biofilm, and the sewage is widely contacted with the biofilm. Under the effect of the metabolism of microorganisms on the biofilm, the organic pollutants in the sewage are removed, and the sewage is purified.Finally, the treated wastewater is discharged into the biological contact oxidation treatment system anddomestic sewageIt shall be treated after mixing, and discharged after chlorine disinfection.The biological contact oxidation process is a biofilm process between the activated sludge process and the biological filter, which is characterized by the installation offiller, pool bottomaerationThe sewage is oxygenated, and the sewage in the tank is in the flow state, so as to ensure that the sewage is fully contacted with the filler immersed in the sewage, and avoid the defect of uneven contact between sewage and filler in the biological contact oxidation tankAeration deviceIt is called blast aeration.
Microbial fuel cellThe treatment method is to degrade toxic substances, organics and impurities by using waste degrading microorganisms inoculated in the fuel cell.Common microbial fuel cells can be divided into single chamber microbial fuel cells and dual chamber microbial fuel cells.
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Adopt reasonableWater treatment processIn combination with the advanced treatment of water, the treated water can meet the standards of GB5084-1992 and CECS61-94 for reclaimed water, which can be recycled for a long time and save a lot of water resources.The following are commonly used agents for wastewater treatment:
(1) Flocculant: sometimes called coagulant, it can be used as a means to strengthen solid-liquid separation, and is used in primary sedimentation tank, secondary sedimentation tank, flotation tank, tertiary treatment or advanced treatment and other process links.
(2) Coagulant aid: it helps the flocculant to play a role in strengthening the coagulation effect.
(3) Conditioning agent: also known as dehydrating agent, which is used for conditioning the residual sludge before dehydration. Its varieties include some of the above flocculants and coagulant aids.
(4) Demulsifier: sometimes called destabilizing agent, it is mainly used for pretreatment of oily wastewater containing emulsified oil before flotation, and its varieties include some of the above flocculants and coagulant aids.
(5) Defoamer: It is mainly used to eliminate a large amount of foam in the process of aeration or mixing.
(6) PH regulator: used to adjust the pH value of acidic wastewater and alkaline wastewater to neutral.
(7) Redox: used for the treatment of industrial wastewater containing oxidizing or reducing substances.
(8) Disinfectant: It is used for disinfection after wastewater treatment and before discharge or reuse.The final treatment step of the secondary treatment plant is to add disinfectant to the outlet water. The most commonly used disinfectant in the United States is chlorine or other forms of chlorine.[4]
Hierarchical processing
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According to the degree of treatment, wastewater treatment (mainly urban domestic sewage and someindustrial waste water）Generally, it can be divided into three levels.
The primary treatment task is to remove suspended solid pollutants from wastewater.For this reason, physical treatment is often used.Generally, after primary treatment, the removal rate of suspended solids is 70%~80%, whileBiochemical oxygen demandThe removal rate of BOD is only about 25%~40%, and the purification degree of wastewater is not high.
The task of secondary treatment is to remove organic pollutants in wastewater by a large margin. Taking BOD as an example, 80%~90% of BOD in wastewater can be removed after secondary treatment. For example, the BOD content in water after urban sewage treatment can be less than 30 mg/l.Most treatment units of aerobic biological treatment method can meet this requirement.
The task of tertiary treatment is to further remove pollutants that cannot be removed by secondary treatment, including organic matter, phosphorus, nitrogen and soluble inorganic matter that cannot be degraded by microorganisms.Tertiary processing is synonymous with advanced processing, but they are not completely consistent.Tertiary treatmentIt refers to one or several treatment units added after secondary treatment to remove certain pollutants, such as phosphorus and nitrogen, from wastewater;Advanced treatment is often a treatment unit or system added after secondary treatment for the purpose of wastewater recovery and reuse.The tertiary treatment is expensive and complex in management, but it can make full use of water resources.A few countries have built some tertiary sewage treatment plants.
Treatment process
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Pretreatment unitThe pretreatment processes for urban wastewater can include:Coarse screen（a grille）, medium screening, crushing, flow measurement, pump lifting, slag removal, pre aeration, flotation, flocculation and chemical treatment.
Flotation, flocculation and chemical treatment are generally not required for domestic sewage treatment.The adoption of such methods is sometimes determined by industrial wastewater in urban wastewater.The flotation method is used to remove fine suspended solids, extract fat and fat in a separate unit or in a pre aeration tank for removing grease and sometimes slag.If the petroleum industry and meat processing plants have proper pretreatment, the urban processing plants may not need flotation units.Flocculation with or without chemical agent can be used to improve the primary treatment effect and prevent overload of secondary treatment process for high strength urban wastewater.Sometimes chlorine is added to the raw wastewater to control the odor and improve the sedimentation property of the wastewater.The change of pre-treatment unit layout depends on the characteristics of raw wastewater, the next treatment process and the pre-treatment unit used.Some general principles are often applicable to unit layout.The grid is used to protect the water pump and prevent solids from scaling in the sediment tank or metering tank.The small treatment plant normally discharges one pump in front of the constant speed lift pumpBabbitt metering tank。In large treatment plants or where variable speed pumps are used, metering tanks can be placed behind the pumps.In most independent domestic sewage plants, the sediment tank is placed behind the lift pump, but when the sludge load is predicted to be large, the sediment tank should be placed in front of the pump.
Primary processing unitThe primary treatment is precipitation, however, the so-called primary treatment commonly includes pretreatment process.All large city treatment plants adopt the raw sewage sedimentation method and must be located in front of the conventional biological filter.Complete mixed activated sludge process can be used to treat raw wastewater without sedimentation. However, due to the reasons of sludge disposal and operation cost, such process is only used in small towns.
Secondary processing unitActivated sludge process, biological filter or stabilization pond are adopted for secondary biological treatment.In the design of the new sewage treatment plant,High load biological filterHas widely replacedLow load biological filterThe fully mixed sludge process is replacing the conventional activated sludge process.Stabilization ponds are generally limited to small towns.
In large-scale treatment plants, high load biological filtration and fully mixed activated sludge are the two most common methods currently used for secondary treatment.The advantage of biological filter is that it is easy to operate and can accept sudden load and overload without causing complete failure.The fully mixed activated sludge process can withstand sudden load but will fail under long-term overload.For example, when the BOD load of the biological filter increases from the design load of 45 pounds/1000 feet 3/day (R=1) to 90 pounds/1000 feet 3/day (R=2), the efficiency decreases from 77% to 70%.When an activated sludge unit is overloaded to the same extent, it will become invalid due to sludge bulking and loss of activated sludge solids in the effluent.The efficiency of BOD removal is reduced from 90% to below 50%.
The advantage of fully mixed activated sludge process is that it has high BOD removal efficiency, can treat high strength wastewater and is adaptable to the future transition to advanced treatment.For the secondary treatment of a strong wastewater with 300 mg/l of settleable BOD, the secondary treatment of activated sludge can remove at least 90% of BOD, and its effluent BOD is equal to or less than 30 mg/l.The single-stage high load biological filter can only remove 77% or less of BOD, and its effluent BOD is about 70 mg/l.In order to make the removal efficiency of BOD comparable to that of activated sludge process, two-stage filtration is required.
Sludge disposalThe volume of wastewater organics condensed into sludge by primary sedimentation and secondary biological flocculation is much smaller than that of wastewater treated.However, the disposal of accumulated waste sludge is a major economic factor in wastewater treatment.The primary investment of sludge processing equipment is about one third of the investment of the treatment plant.Settled solids or residual activated sludge clarified from the effluent of the biological filter are often sent back to the head of the treatment plant for removal together with the primary sludge.Raw sludge can be stored inPrimary sedimentation tankThe bottom is waiting for treatment or pumped to a storage tank for storage. The extracted sludge can be concentrated in a concentration tank, which is usually a gravity unit and placed before sludge processing.The residual activated sludge is mixed with the primary sludge after extraction.In the system layout, a regulation tank and a sludge thickener are generally used.The residual activated sludge can be thickened separately or by mixed sludge before processing.
Various methods of sludge processing and disposalThe common sludge processing methods are anaerobic digestion and vacuum filtration, and centrifugation and wet burning are often used.The conventional disposal methods include landfill, incineration, manufacturing of soil conditioner and shipping to the sea.In coastal cities and cities, it is often the most economical to ship to the sea, and if there is ground, the landfill rule is used to.Incineration, although expensive, is often the only feasible disposal method in urban areas.
An urban treatment plant must carefully consider all possible sludge disposal processes.The best method to select should be the most economical process that takes proper care of environmental conditions. Attention must be paid to such factors as the future use of the sludge after transportation and processing in residential areas and landfill areas, groundwater pollution, air pollution, other potential public health hazards and wind problems.
chlorinationWhere the water area at the tail end is used as a tourist or water supply source, disinfection of the effluent from the secondary treatment plant is a common method.Several states initially stipulated that the effluent from the treatment plant should be disinfected only in the water area tour season, but now require year-round disinfection.Some states do not make any such provisions.
Phosphorus and nitrogen removalIn recent years, a lot of research work has been done on the development of feasible phosphorus removal methods in wastewater treatment plants.The development of methods for nitrogen removal and complete water recovery has also been studied.There are several pilot plants and small-scale production plants for phosphorus removal in operation, but as a precedent for the design of large-scale equipment, the experience data is still limited.Although water quality standards stipulate the limits of phosphorus and nitrogen, large-scale application of nutrient removal methods is still in the future.
Town sizeFor small towns, the leading role in the selection of wastewater treatment process is the management, control and disposal of sludge.The method of not disposing sludge (stabilization pond) or only occasionally pumping sludge (delayed aeration) is superior to small villages and districts.Larger towns often use systems that require more control and maintenance, that is, treatment plants with contact stability and oxidation ditches.Many existing treatment systems are no longer popular, such as hidden ponds and other types selected according to unique local conditions.
Treatment unit series in biological filter treatment plantBucket bottom sediment tank with independent slag washing tank, primary sedimentation tank, biological filter, final sedimentation tank with gravity return to the original wastewater wet well circulating pipeline, single-stage digestion tank and drying bed for sludge treatment.The following wastewater flows back to the original wastewater wet well: the overflow of the slag washing tank, the return sludge of the final sedimentation tank, the drainage water of the drying plant and the clarified liquid of the digestion tank.The treatment plant can set an override pipe at the inlet inspection well or after the biological filter.
Activated sludge plant treatment unit seriesA mechanically cleaned grid and a crusher to send the chopped solids back to the original wastewater, a constant speed and variable speed lift pump of the standby gas unit, a Babbitt metering tank, a clarifier type aerated sediment tank with an independent slag washer, a primary sedimentation tank, a secondary treatment tank for fully mixed activated sludge and a gravity return pipeline for excess sludge to the wet well,Landfill site for raw sludge vacuum filter and filter cake disposal from sludge storage tank.Vacuum filterThe filtrate of is returned to the wet well.Due to the buried depth of wastewater pipe, the original wastewater cannot be exceeded by gravity flow before wet well.A standby gas unit is set for the lifting pump of two sides and three knife tables, which can operate in case of power failure.The overtaking pipeline is set after the lift pump station and after the primary sedimentation tank.
Processing technology
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Pretreatment
[Technical Overview]
In order to protect the equipment of the wastewater treatment plant, some facilities and structures are placed before the primary treatment operation, because the BOD is reduced through these facilities and structuresfiveThe effect of is very limited, so this process is called pretreatment.[4]
Micro electrolysis technology is an ideal process for the treatment of high concentration organic wastewater. This process can not only greatly reduce cod and chroma, but also greatly improve the biodegradability of wastewater when applied to the treatment of high salinity, refractory and high chroma wastewater.
This technology is filled in the micro electrolysis equipment without power supplyMicro electrolysis fillerProduce "galvanic cell" effect to treat wastewater.When water is supplied, countless potential differences up to 1.2V will be formed in the equipment“Primary battery”。"Primary battery" is made of waste waterelectrolyte, viadischargeThe current is formed to conduct electrolytic oxidation and reduction treatment on the wastewater to achieve the purpose of degrading organic pollutants.The new ecology [? OH], [H], [O], Fe2+, Fe3+, etc. generated in the treatment process can have redox reactions with many components in the wastewater, such as destroying the chromophore of colored substances in the colored wastewater orChromophore, even broken chain, to achieve the role of degradation and decolorization;The generated Fe2+is further oxidized to Fe3+, and their hydrates have strong adsorption flocculation activity, especially after adding alkali to adjust the pH valueFerrous hydroxideandFerric hydroxide colloidFlocculants, whose flocculating capacity is far higher than that of ordinary agentshydrolysisThe obtained ferric hydroxide colloid can flocculate a large number of dispersed small particles, metal particles and organic macromolecules in water. Its working principle is based onelectrochemistry, oxidation-reduction, physical andflocculent settling The joint action of.The process has the advantages of wide application range, good treatment effect, low cost, short treatment time, convenient operation and maintenance, low power consumption, and can be widely used in the pretreatment and advanced treatment of industrial wastewater.
[Technical Features]
(1) The reaction rate is fast, and it only takes half an hour to several hours for general industrial wastewater;
⑵ The range of organic pollutants is wide. For example, the refractory organic substances with even fluoride, carbon double bond, nitro group and halogenated group structure have good degradation effect;
Effect picture of micro electrolysis filler
⑶ The process flow is simple, the service life is long, the investment cost is small, the operation and maintenance is convenient, the operation cost is low, and the treatment effect is stable.Only a small amount of micro electrolysis filler is consumed in the treatment process.The filler only needs to be added regularly without replacement, and can be directly put into use when adding.
⑷ After micro electrolysis treatment, the wastewater will form original ferrous or iron ions in the water, which has better coagulation effect than ordinary coagulants. There is no need to add coagulants such as ferric salt, which has high COD removal rate and will not cause secondary pollution to the water;
(5) It has good coagulation effect, high chroma and COD removal rate, and the same amount can greatly improve the biodegradability of wastewater.
(6) This method can achieve the effect of phosphorus removal by chemical precipitation, and can also remove heavy metals by reduction;
(7) For the high concentration organic wastewater treatment projects that have not reached the standard, this technology can be used as the pretreatment of the wastewater of the projects that have been built to ensure the stable discharge of the wastewater after treatment.Some wastewater with high concentration in production wastewater can also be separately led out forMicroelectrolysishandle.
(8) Each unit of this technology can be used as a separate treatment method, and can also be used as a pre-treatment process for biological treatment, which is conducive to sludge settlement and biofilm formation
[Applicable wastewater type]
(1) Dye, chemical and pharmaceutical wastewater;Coking and petroleum wastewater------The BOD/COD value of the above treated wastewater has been greatly improved.
⑵. Printing and dyeing wastewater;Leather wastewater;Papermaking wastewater and wood processing wastewater;
------It has good application for decolorization, and effectively removes COD and ammonia nitrogen.
⑶. Electroplating wastewater;Printing wastewater;Mining wastewater;Other wastewater containing heavy metals;
------Heavy metals can be removed from the above wastewater.
------The biodegradability of the above wastewater can be greatly improved, and phosphorus and sulfide can be removed.
New packing
[Technical Overview]
It is made of multi metal alloy fusion catalyst and high temperature microporous activation technology. It is a new type of feeding type non hardening micro electrolysis filler.When applied to wastewater, it can effectively remove COD, reduce chroma, improve biodegradability, achieve stable and lasting treatment effect, and avoid filler passivation and hardening during operation.This packing isMicroelectrolysisThe important guarantee of continuous reaction has brought new vitality to the current treatment of chemical wastewater.
[Iron carbon primary cell reaction]
Anode: Fe - 2e → Fe2+E (Fe/Fe2+)=0.44V
Cathode: 2H ＋+2e → H2 E (H ＋/H2)=0.00V
In the presence of oxygen, the cathodic reaction is as follows:
O2 + 4H﹢ + 4e → 2H2O E （O2）=1.23V
O2 + 2H2O + 4e → 4OH﹣ E（O2/OH﹣）=0.41V
Ceramic membrane
Ceramic membrane, also known as GT membrane, is an asymmetric membrane made of inorganic ceramic materials by special process, which is tubular or multi-channel.The ceramic membrane wall is densely covered with micropores. Under the pressure, the raw liquid flows in the membrane tube or outside the membrane, and small molecules (or liquids) pass through the membrane,Macromolecular substances(or solid particles, liquid droplets) are trapped by the membrane to achieve the purpose of solid-liquid separation, concentration and purification.
Organic membrane has been developed and applied earlier in the field of membrane science and technology. This kind of membrane is easy to prepare, easy to form, good in performance and cheap in price, and has become the most widely used microfiltration membrane type.However, with the development of membrane separation technology and its application, higher and higher requirements are put forward for the use conditions of membrane. It is necessary to develop an extreme condition membrane solid-liquid separation system. Compared with organic membrane,Inorganic ceramic membraneHigh temperature resistancechemical stabilityGood, acid resistant, alkali resistant, organic solvent resistant, high mechanical strength, backwashing, strong anti microbial ability, strong cleanabilityPore size distributionNarrow, high permeability, high membrane flux, good separation performance and long service life.
There are two main obstacles to the application of inorganic ceramic membrane in wastewater treatment. One is the complex manufacturing process, high cost and high price;The second is the problem of membrane flux. Only by overcoming membrane pollution and improving membrane filtration flux, can it be truly applied to all fields of water treatment.
[Features]
(1) Unique double-layer membrane structure: polyester bait DEAR inorganic ceramic membrane system On the surface of the membrane filter layer, TiO2 sol is prepared by sol-gel method, and nano TiO2 is coated on the ceramic membrane by dip pulling methodPhotocatalytic materialsTo make the ceramic membrane surface have the function of "self-cleaning", slow down the accumulation and blockage of organic on the membrane surface, on the one hand, reduce membrane pollution, on the other hand, improve the strength of ceramic membrane tubes and membrane filtration flux, and improve the stability of membrane flux;Al2O3-ZrO2 composite membrane structure: it makes the mechanical properties of the membrane tube more excellent. Due to the performance defects of the material itself or some practical problems in the preparation process, a single inorganic membrane material generally cannot meet the actual needs, so the development of inorganic loaded composite separation membrane has been developed rapidly. The polyester bait DEAR inorganic ceramic membrane adopts the overall composite technology through the sol-gel method,To prepare Al2O3-ZrO2 composite membrane, as the materials containing ZrO2 have better mechanical strength, chemical durability and alkali corrosion resistance than Al2O3, SiO2, TiO2 and other materials, polyester bait DEAR®；The inorganic ceramic membrane has stronger mechanical strength and thermal stability, and the pore size distribution of the composite membrane is narrow, showing a single peak.
⑵ Online backwash and stable membrane flux can be achieved: due to the unique structure and mechanical properties of the composite ceramic membrane, it can effectively withstand the backwash pressure below 0.4mp, which can achieve online backwash, thus obtaining stable membrane flux, overcoming the problems of high price, easy pollution, small membrane flux, huge equipment and other problems of inorganic membrane systems in water treatment applications,It makes the application of inorganic ceramic membrane system in water treatment possible.The polyester bait DEAR inorganic ceramic membrane is specially designed for sewage treatment. Its biggest feature is that the membrane flux is large. Its operating membrane flux is 10-100 times that of organic membrane, 50-10 times that of ordinary porous ceramic membrane. It has high mechanical strength, pollution resistance, and can realize online backwash.
Technical Parameters
Film thickness: 50-60 μ m, film aperture 0.01-0.5 μ m;
Detoxification treatment of industrial aquaculture raw water;
Power plants, chemical plants and other large-scale cooling circulating water bypass filtration systems;
Reuse and treatment of oilfield produced water;
Treatment of waste rolling emulsion;
Regeneration treatment of metal surface cleaning solution.
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Historically, wastewater has been regarded as a harmful thing and needs to be disposed of in the cheapest way that will not affect the environment as much as possible.This means that on-site disposal systems can be used, such as the wastewater from latrines, which can be directly discharged into rivers and lakes.In the past century, people have realized that these methods will have adverse effects on the environment.This enables people to develop a variety of treatment technologies, such as today's urban wastewater treatment system.If we look ahead, we must regard wastewater as a raw material for economic benefits and sustainable development.Clean water is becoming scarce, so wastewater should be treated and reused.Nutrients rich in wastewater, such as nitrogen and phosphorus, are recycled in some treatment processes and used to grow crops.In order to achieve a sustainable future, we must use this method more and more, and strive to improve the energy utilization rate in wastewater.[4]
