CN114772871A - Treatment method of polyformaldehyde production wastewater - Google Patents

Treatment method of polyformaldehyde production wastewater Download PDF

Info

Publication number
CN114772871A
CN114772871A CN202210586365.1A CN202210586365A CN114772871A CN 114772871 A CN114772871 A CN 114772871A CN 202210586365 A CN202210586365 A CN 202210586365A CN 114772871 A CN114772871 A CN 114772871A
Authority
CN
China
Prior art keywords
wastewater
reactor
polyformaldehyde
formaldehyde
production
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202210586365.1A
Other languages
Chinese (zh)
Other versions
CN114772871B (en
Inventor
刘霞
卢毅明
鲍磊
朱核光
徐祖武
赵宁华
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SHANGHAI ZHONGYAO ENVIRONMENTAL PROTECTION INDUSTRIAL CO LTD
Original Assignee
SHANGHAI ZHONGYAO ENVIRONMENTAL PROTECTION INDUSTRIAL CO LTD
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SHANGHAI ZHONGYAO ENVIRONMENTAL PROTECTION INDUSTRIAL CO LTD filed Critical SHANGHAI ZHONGYAO ENVIRONMENTAL PROTECTION INDUSTRIAL CO LTD
Priority to CN202210586365.1A priority Critical patent/CN114772871B/en
Publication of CN114772871A publication Critical patent/CN114772871A/en
Application granted granted Critical
Publication of CN114772871B publication Critical patent/CN114772871B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/467—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction
    • C02F1/4672—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction by electrooxydation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5281—Installations for water purification using chemical agents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/58—Treatment of water, waste water, or sewage by removing specified dissolved compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/722—Oxidation by peroxides
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F2001/007—Processes including a sedimentation step
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C02F2101/34—Organic compounds containing oxygen
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
    • C02F2103/36—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds
    • C02F2103/38—Polymers
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2203/00—Apparatus and plants for the biological treatment of water, waste water or sewage
    • C02F2203/004—Apparatus and plants for the biological treatment of water, waste water or sewage comprising a selector reactor for promoting floc-forming or other bacteria
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/02—Temperature
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/06—Controlling or monitoring parameters in water treatment pH
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2305/00—Use of specific compounds during water treatment
    • C02F2305/02—Specific form of oxidant
    • C02F2305/026—Fenton's reagent
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2305/00—Use of specific compounds during water treatment
    • C02F2305/06—Nutrients for stimulating the growth of microorganisms
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/30—Aerobic and anaerobic processes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00—Technologies for wastewater treatment
    • Y02W10/10—Biological treatment of water, waste water, or sewage

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Removal Of Specific Substances (AREA)

Abstract

The invention discloses a method for treating wastewater from polyformaldehyde production, and relates to the technical field of polyformaldehyde wastewater treatment. The wastewater from the polyformaldehyde production sequentially passes through a regulating tank, a polymerization reactor 1, a polymerization reactor 2, a pH adjusting tank, a cooling tower, a biological selector, an anaerobic hydrolysis composite reactor, an aerobic composite reactor, a radial flow sedimentation tank, a high-efficiency coagulating sedimentation tank and a heterogeneous Fenton oxidation reactor, and water and sludge are discharged. The formaldehyde is converted into thexylulose or hexose or derivatives thereof by adopting the formose reaction principle, thereby eliminating the toxicity to microorganisms and improving the biodegradability of wastewater. The formose reaction adopts a double-alkali method, namely, the pH value is adjusted, and the catalyst adopts alkali metal alkali and alkaline earth metal alkali respectively, so that the conversion rate of formaldehyde is higher, the operation cost is lower, and the scaling problem is avoided. The method is economical, efficient and stable, and the treated wastewater can be directly discharged.

Description

Treatment method of polyformaldehyde production wastewater
Technical Field
The invention relates to the technical field of polyformaldehyde wastewater treatment, and particularly relates to a method for treating polyformaldehyde production wastewater.
Background
Paraformaldehyde is an industrial raw material with wide application, and is widely applied to synthesis of pesticides, synthetic resins and coatings and preparation of fumigation disinfectants. The industrial synthesis method of paraformaldehyde mainly uses methanol as a raw material and prepares the paraformaldehyde through the steps of oxidation, catalytic polymerization and the like. Paraformaldehyde wastewater generated in the production process of paraformaldehyde contains a large amount of formaldehyde, paraformaldehyde (DOX), Trioxymethylene (TOX), methanol, sodium formate and other pollutants, and is typical high-concentration organic wastewater with poor biodegradability. Formaldehyde is a commonly used disinfectant, commonly known as formalin, and can cause protein denaturation, so that it has a strong killing effect on bacteria and also has strong toxicity on human and animals. As a rule, the formaldehyde content of the secondary emission standard is not higher than 2 mg/L. If the concentration of formaldehyde contained in the wastewater is higher (more than or equal to 200mg/L), the biodegradability of the wastewater can be seriously reduced, so that the concentration of the formaldehyde in the formaldehyde-containing wastewater, especially the organic wastewater containing high-concentration formaldehyde, needs to be reduced by a targeted method, and other components in the wastewater are removed by an effective method and then can be discharged.
At present, the treatment of the wastewater containing formaldehyde usually adopts chemical, physical and chemical methods and biochemical methods or a combination of several methods.
Chinese patent CN105819564 proposes a method for treating paraformaldehyde wastewater, which comprises treating wastewater with a particulate carrier impregnated with a noble metal (ruthenium, rhodium, or palladium) catalyst at about 200 ℃ and 2-4Mpa pressure to perform wet catalytic oxidation of organic substances in the wastewater. The method is carried out at high temperature and high pressure, and has high requirements on a treatment device and high energy consumption.
Chinese patent CN105060553 discloses a treatment method of formaldehyde wastewater, which comprises the steps of adding calcium hypochlorite into the wastewater, stirring and reacting for 1-3 hours, and then adding hydrochloric acid or sulfuric acid to adjust the pH value of the liquid after reaction to 1-5. The invention does not disclose whether the waste water after treatment needs to be neutralized, but a large amount of calcium hypochlorite, acid and alkali are needed in the reaction, and the corrosion prevention requirement of the device is extremely high.
Chinese patent CN108246290 discloses an oxidation catalyst for removing formaldehyde from wastewater and a preparation method thereof. The new catalyst adopts manganese-based composite oxide as a carrier and noble metal (ruthenium, rhodium, platinum or palladium) as a catalytic active component, and can adsorb formaldehyde on the surface of a filter material at room temperature and convert the formaldehyde into carbon dioxide and water. The method does not describe whether the catalyst has a removing effect on other components in the wastewater.
The treatment of formaldehyde wastewater with hydrogen peroxide under alkaline conditions has been reported ("research on formaldehyde wastewater treatment with basic hydrogen peroxide", populus, and so on "), but hydrogen peroxide decomposes oxygen when exposed to heat or light, and the generation of a large amount of oxygen causes explosion of a closed container, and the storage of a large amount of hydrogen peroxide has potential safety hazards. It has also been reported that the treatment of formaldehyde wastewater with ozone ("research on the photocatalytic degradation of formaldehyde in water", lujing xia, etc.), but the ozone treatment requires the use of a catalyst or the irradiation of ultraviolet light, and the effect of ozone alone is not ideal.
Chinese patent CN107879502 proposes a pretreatment method of formaldehyde wastewater, which comprises treating suspended solid SS of wastewater to less than 80mg/L by coagulating sedimentation, adjusting pH of wastewater to weak acidity range of 2-6 with acid or alkali, and adding Na according to a certain molar ratio2SO3And reacting for 0.5-1 hour. The formaldehyde is reduced into alcohols by the reaction, and the alcohols have low toxicity to organisms, so that the biodegradability of the wastewater can be improved, and the subsequent biochemical treatment is facilitated. The method needs to adopt coagulation sedimentation in advance, so that a part of organic matters can directly enter the sedimentary sludge without biological treatment, and in addition, the requirement on the corrosion resistance of the device is high by adjusting the pH value to be acidic.
Chinese patent 201320863274.4 discloses a method for treating industrial wastewater containing formaldehyde, the wastewater, melamine and catalyst enter a reaction kettle to carry out mixing reaction to generate crystal, then the crystal enters a multistage sedimentation tank to carry out sedimentation separation, supernatant liquid and 40-70% of raw material formaldehyde are mixed to prepare 35-40% of dilute formaldehyde, and the precipitate returns to the reaction kettle to be recycled. The method realizes zero emission, formaldehyde enters subsequent products, but the reaction is only suitable for the situation that the formaldehyde waste liquid with high concentration and the components of the waste liquid are relatively pure.
Chinese patent CN101830604 discloses a process for treating formaldehyde wastewater by using waste alkali liquor, wherein the wastewater enters a polymerization reaction tank after being uniformly mixed in an adjusting tank, industrial waste alkali liquor is added to adjust the pH to be more than 9, and in addition, steam is required to be introduced to ensure that the temperature reaches more than 40 ℃. Under the condition, formaldehyde is polymerized to generate polysaccharide substances such as glucose and the like, and the residence time of the polysaccharide substances in the polymerization reaction tank is 0.1-80 h. The method uses waste alkali, and avoids using Ca (OH)2And calcium oxide is used as an alkaline agent for polymerization reaction, so that the treatment cost is reduced. However, the invention does not specifically suggest the components of the waste alkali, and the several listed examples of the waste alkali contain sodium alkali, and the specific reaction and the catalyst used are not described in detail, and the specified residence time of the polymerization reaction is too wide to technically indicate the actual reaction time required for the polymerization reaction, which is equivalent to that no specific technical specification is made.
Chinese patent CN112456716 discloses a pretreatment method of formaldehyde wastewater, formaldehyde wastewater enters a collection tank, the pH value of the formaldehyde wastewater is adjusted to 11-13 by alkali liquor such as NaOH, the formaldehyde wastewater is preheated to 60-80 ℃, and then the formaldehyde wastewater enters a catalytic reaction tower, and solid CaCO is used as a catalyst3So that the formaldehyde is subjected to glycan reaction for 3-5h, and finally the wastewater enters a collecting tank to adjust the pH back to be neutral. The method introduces granular CaCO3As a catalyst for the formose reaction, the cost is relatively low. However, CaCO is not disclosed in this patent3As a catalytic mechanism for the catalyst, CaCO3Extremely low solubility under alkaline conditions, requiring the use of large amounts of CaCO in order to allow the catalytic reaction to proceed completely3And a fixed bed reaction tower is required to be arranged, a large amount of CaCO is used3Fouling problems can also be caused in the treatment apparatus.
The reaction of converting formaldehyde into saccharides by polymerization (known as glycan reaction, also known as Formose method) needs to be carried out effectively at a suitable temperature and under the action of a suitable catalyst, which is mainly used for complexing with formaldehyde or intermediate products of the reaction, so as to change the charge distribution of the formaldehyde or the intermediate products, and enable the polymerization of formaldehyde to occur. There are many catalysts for formose reaction, and the common catalysts include alkali metal, alkaline earth metal hydroxides and oxides, metal oxides or chlorides, organic bases (such as organic amines), thiazoles, etc. The choice of catalyst and the conditions will result in a different end product of the glycan reaction, for example if it is carried out in Ca (OH)2As a catalyst, formaldehyde polymerization involves multiple steps including aldol condensation, acyloin condensation, translocation and cross reaction, resulting in over 30 products, which have both 2-or 3-carbon aldol and ketose and hexose such as glucose, and if certain organic amines and thiazole-based catalysts are used, selectivity is better and polysaccharide reaction is more prone to ketose and hexose formation.
In summary, the existing treatment process of formaldehyde wastewater generally adopts an oxidation method or a catalytic oxidation method to completely oxidize and decompose formaldehyde into harmless CO2And water, or converting formaldehyde into saccharides by polymerization of formaldehyde, and treating by biochemical method. The oxidation method is not specially used for formaldehyde, other organic pollutants in the wastewater can be oxidized, a large amount of oxidant is inevitably consumed, meanwhile, a catalyst is often used for a complete oxidation reaction at normal temperature and normal pressure, the use of the catalyst not only increases the treatment cost, but also the used catalyst belongs to hazardous waste because the catalyst generally contains rare earth or noble metal, and the final treatment cost of the hazardous waste is very high. As formaldehyde wastewater, especially high-concentration formaldehyde wastewater, the wastewater subjected to polymerization reaction has certain specificity in components and properties, not only has high alkalinity and temperature, but also contains high-concentration carbohydrate and salt, and the main organic substances treated by the activated sludge method in the general wastewater biological treatment process are protein and low moleculesThe post-treatment process of the organic acids, saccharides and salts is not described at all.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a method for treating wastewater from polyformaldehyde production, which is economic, efficient and stable, and the treated wastewater can be directly discharged.
In order to achieve the purpose, the invention provides the following technical scheme:
a treatment method of wastewater from polyformaldehyde production comprises the following steps:
the wastewater from the production of polyformaldehyde (wherein the concentration of formaldehyde can reach more than 1000ppm or even thousands of ppm) passes through a regulating tank, a polymerization reactor 1, a polymerization reactor 2, a pH adjusting tank, a cooling tower, a biological selector, an anaerobic hydrolysis composite reactor, an aerobic composite reactor, a radial flow type sedimentation tank, a high-efficiency coagulating sedimentation tank and a heterogeneous Fenton oxidation reactor in sequence, and water and sludge are discharged;
the polymerization reactor 1 was operated as follows: adding a catalyst into the wastewater from polyformaldehyde production, adjusting the pH value with an alkali liquor, stirring, and carrying out a polymerization reaction at 40-80 ℃. Preferably 50-60 deg.C. The polymerization reactor 1 is provided with a stirring device, a pH probe and a temperature probe, the increase of the water temperature in the pool is obtained by introducing water vapor or adopting electric heating, and when the temperature reaches a set value, the heating is stopped.
The molar ratio of the catalyst to formaldehyde in the wastewater from polyformaldehyde production is (0.1-1): 1. preferably (0.3-0.5): 1.
the catalyst is any alkaline earth metal hydroxide, preferably Ca (OH)2Solutions or Mg (OH)2The solution may be a waste solution containing the component.
The alkali liquor is any alkali metal hydroxide, preferably NaOH solution or KOH solution, and can also be waste liquor containing alkali liquor. The pH is adjusted to be more than or equal to 9. Preferably 9-10.
In order to ensure that the reaction can be carried out more completely, the wastewater from the production of polyformaldehyde enters the polymerization reactor 2 for further reaction, the polymerization reactor 2 is provided with a stirring device for mixing and stirring, no reagent is added, so the reaction condition is more uniform, the residence time of the polymerization reactor 2 and the residence time of the polymerization reactor 1 can be equal to or greater than the former, but the total residence time of the two tanks is 3-14 h. The total residence time is selected in accordance with the concentration of formaldehyde and the conversion to be achieved, the higher the concentration, the higher the conversion requirement and the longer the residence time required.
Further, adding acid liquor into the pH adjusting tank, adjusting the pH to 7-8, wherein the addition amount is 1-4% of the mass of COD in the wastewater from the polyformaldehyde production. The acid solution is phosphoric acid, hydrochloric acid or sulfuric acid, or a mixed acid or waste acid solution containing the acids, and phosphoric acid is preferably added in the invention.
Furthermore, the cooling tower is preferably a natural evaporation cooling tower, the water is cooled to 35-40 ℃, the circulating water quantity of the cooling tower and the air draft quantity of the axial flow fan are adjusted according to the water temperature in the water collecting tank of the cooling tower, and the water temperature is ensured to be lower than 37 ℃ when the polyformaldehyde production wastewater enters the biological selector.
The cooled wastewater enters a biological selector. The biological selector further adjusts the nutrition ratio of the water quality, supplements necessary nitrogen sources (the addition amount of the nitrogen sources is determined by controlling the carbon-nitrogen-phosphorus ratio), and adds domestic sewage to supplement nitrogen and phosphorus in the wastewater, so that the mass ratio of the biological oxygen demand (COD), the Total Nitrogen (TN) and the Total Phosphorus (TP) of the mixed wastewater is 100: 5: 1, such components are more favorable for the growth and metabolism of microorganisms; meanwhile, the returned sludge discharged from the sedimentation tank also enters the biological selector, so that the returned sludge and the dissolved oxygen in the raw water can be consumed as soon as possible under the action of the aerobic respiration microorganisms, and the formation of the anaerobic condition of the subsequent anaerobic hydrolysis reactor is facilitated. The traditional method is to return the sludge to the anaerobic tank, so that the dissolved oxygen contained in the returned sludge can impact the operation of the anaerobic reaction tank to influence the operation effect of the anaerobic tank. Various autotrophic and heterotrophic microorganisms contained in the returned sludge are used as inoculation flora to effectively grow and reproduce in the biological selector and the subsequent biochemical functional area, and various organic and inorganic nutrient components contained in the wastewater are effectively decomposed and utilized.
Wastewater from the biological selectorThe flow enters an anaerobic hydrolysis composite reactor. The reactor adopts a hydraulic flow pushing mixing reaction mode, a plurality of mixing reactors are arranged along the water flow direction, power is provided to enable water to flow in a long and narrow channel in the reactor, and the water levels of an inlet and an outlet are kept consistent. The arrangement ensures that the reaction device has enough transverse mixing function, relieves the impact of water quality and water quantity fluctuation on the quality of outlet water, and reduces the oxygen mixed in the air; meanwhile, due to the change of water quality at different longitudinal positions, more kinds of microorganisms and hydrolytic enzymes can be enriched in the whole reactor, organic matters in the wastewater are hydrolyzed and acidified more thoroughly, more macromolecules are cut into micromolecules, and the hydrolytic acidification effect is ensured; and filling materials are placed in the anaerobic hydrolysis composite reactor. The filler is used for providing a fixation carrier for microorganisms, so that more fixation state microorganisms (biological films) can be accommodated in the reaction device, the concentration of the microorganisms in the reactor is improved, the biological phases in the reactor are richer, the volume load of the reactor is increased, and the load impact resistance of the reaction device is further improved. The anchorage growth of the hydrolytic acidification bacteria can also reduce the flow of the microorganisms into the aerobic reaction tank along with the sewage, so that the biological phase of the microorganisms is more specific and stable, and the effect of the hydrolytic acidification process section is further ensured; the filling material is preferably put in a density which can provide at least 3-4 kilograms (dry solid) of microorganism anchorage growth per cubic meter. The filler used by the invention can be any wastewater treatment filler capable of providing microorganism fixation growth, and is preferably a ZYZX series laminated unfolding type microorganism carrier produced by Yao environmental protection industry Co Ltd in the sea, the carrier is made of PE (polyethylene) membranes, and the carrier is spherical and solid after being unfolded, and has the advantages of light weight, large specific surface area, large sludge carrying amount, good strength, no sludge agglomeration and the like. The packing density is 60/m when ZYZX lamination spreading type microorganism carrier is used3。
The effluent of the anaerobic hydrolysis composite reactor automatically flows into an aerobic composite reactor. An aeration device is laid in the aerobic composite reactor for oxygen supply, and a microporous aerator is preferably adopted as the aeration device. In the reaction unit, a large amount of heterotrophic bacteria degrade BOD and other components in the sewage under aerobic conditionsAnd meanwhile, the cells grow and reproduce continuously, absorb nitrogen sources and phosphorus sources and synthesize self cells. And placing a filler in the aerobic reactor. The filler is used for providing a fixation carrier for microorganisms, so that more fixation state microorganisms (biological films) can be accommodated in the reaction device, the concentration of the microorganisms in the reactor is improved, the biological phases in the reactor are richer, the volume load of the reactor is increased, and the load impact resistance of the reaction device is further improved. The filling material is preferably put in a density which can provide at least 2-3 kg (dry solid) of microorganism for fixing and growing according to each cubic meter. The filler used by the invention can be any wastewater treatment filler capable of providing microorganism fixation growth, and is preferably a zyzx series laminated spreading type microorganism carrier produced by Yao environmental protection industry Co Ltd in the sea, and the input density is 60/m3。
And the effluent of the aerobic composite reactor automatically flows into a sedimentation tank for sludge-water separation. The sedimentation tank is preferably in the form of a radial sedimentation tank. Discharging clear liquid obtained after precipitation to coagulating sedimentation for further removing suspended solids and the like, partially refluxing the obtained precipitated sludge to a biological selector for population inoculation and regeneration, and entering the next cycle of hydrolytic acidification and heterotrophic growth, partially conveying the precipitated sludge as residual sludge to a sludge concentration tank for concentration, dehydrating and drying the sludge, and then discharging the sludge, wherein carbon, nitrogen and phosphorus contained in a large amount of thalli contained in the residual sludge are permanently removed from the system.
And a high-efficiency coagulating sedimentation tank is arranged behind the sedimentation tank, suspended solids, total phosphorus, macromolecular difficultly-degraded COD (chemical oxygen demand) components and the like in clear liquid are further removed, precipitated sludge generated by the sedimentation tank and residual sludge of a previous-stage sedimentation tank enter a sludge concentration tank together for sludge treatment, and the obtained clear liquid is discharged into a heterogeneous Fenton oxidation tank for further oxidation treatment.
Filling iron-carbon particle filter materials in the heterogeneous Fenton oxidation tank, wherein the iron-carbon particle filter materials fill the whole filter bed space, the size of the filter bed space enables the retention time of the wastewater in an empty bed to be 1-3h, adding a hydrogen peroxide oxidizing agent into an inlet, and the mass ratio of the addition amount to the COD (chemical oxygen demand) of the wastewater entering the oxidation tank is (1-2): 1. The iron-carbon particle filter material contains active carbon and reduced iron, the reduced iron and the active carbon form an electrochemical system, the reduced iron can release electrons to form ferrous salt, and the ferrous salt is used as a hydrogen peroxide catalyst to ensure that hydrogen peroxide is cracked to generate hydroxyl radicals and oxidize residual organic matters in water, thereby further reducing the COD of the wastewater and ensuring that the discharged water can be directly discharged to the external environment.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides an efficient, reliable and economical treatment process for treating polyformaldehyde wastewater. The high concentration formaldehyde contained in the wastewater is effectively converted into three-carbon and six-carbon saccharides and aldol-like substances under relatively mild conditions in the polymerization reactor, the toxicity to microorganisms is eliminated, and the three-carbon saccharides and the six-carbon aldol-like substances are biochemically removed together with other organic components. The alkaline conditions required for the polymerization are adjusted using alkali metal hydroxides, the catalysts required are alkaline earth metal hydroxides Ca (OH)2Or Mg (OH)2The double-alkali process can reduce the dosage of the alkali agent for adjusting the pH value, can obtain better catalytic effect, can obtain higher formaldehyde conversion efficiency, shortens the required reaction time, and reduces the required reaction temperature.
Phosphoric acid is used in the pH neutralization and callback of the reaction liquid after the polymerization reaction, and the phosphorus source required by the subsequent biological treatment of the wastewater is supplemented while the neutralization effect is achieved. The cooling tower is combined with the pH neutralization and callback, so that the construction cost can be saved; the outlet temperature of the cooling liquid is controlled by the cooling liquid circulating pump of the cooling tower and the frequency conversion regulation of the axial flow fan, and the cooling energy consumption can be reduced on the premise of ensuring the cooling effect.
The pretreatment method (the adjusting tank, the polymerization reactor 1 and the polymerization reactor 2) adopted by the invention can prevent organic matters in the wastewater from being influenced by pretreatment, and the wastewater is purified by a biological method, so that the treatment cost is lower than that of the existing oxidation process. The biological treatment process adopts anaerobic hydrolysis acidification and aerobic biological treatment, can ensure that high-concentration organic matters, especially components of macromolecules in the wastewater can be effectively removed, and has stable treatment effect. By arranging the biological selector, adopting a plug-flow mixed reaction mode and corresponding power machinery in the anaerobic hydrolysis composite reactor and the aerobic reactor and filling special biological fillers, the process can realize optimization on the removal efficiency of suspended solids and organic matters, and simultaneously keep the stability and reliability of the system operation.
The pretreated wastewater passes through a pH adjusting tank and a cooling tower, is mixed with plant area miscellaneous wastewater such as domestic sewage and the like, and then is biologically treated, and the wastewater sequentially enters a biological selector, an anaerobic hydrolysis composite reactor, an aerobic composite reactor, a radial flow type sedimentation tank, a high-efficiency coagulating sedimentation tank, a heterogeneous Fenton oxidation reactor and other treatment units, so that the water quality reaches the discharge standard of level A. Special fillers are placed in the reaction units of the anaerobic hydrolysis composite reactor and the aerobic composite reactor to ensure the treatment effect of the system.
The polymerization reactor 1 uses NaOH as a base and Ca (OH) as a catalyst2The two bases are used, so that the use amount of the bases can be greatly reduced. The alkali metal hydroxide has a stronger ability to supply hydroxide ions, and is advantageous in increasing the pH of the reaction system, but is more advantageous as a ligand for formaldehyde and an ion of an alkaline earth metal having a catalytic function, and the use of these two bases in combination can reduce the amount of each base used, particularly Ca (OH)2The amount of the water is not easy to scale in the subsequent treatment device.
The radii of sodium ions and calcium ions are different, the potential of charges of the outer layers is different, so that the strength of coordination ions formed by the sodium ions and the calcium ions is different, the sodium ions are easier to hydrate the ions and mainly exist in the form of the hydrate ions in the solution, the calcium ions can form firmer ligands with formaldehyde to promote the polymerization reaction between organic matters such as formaldehyde, NaOH can provide more hydroxide radicals for the solution, and the pH is adjusted to be higher than that of Ca (OH)2Is more effective.
After formaldehyde polymerization reaction, the concentration of formaldehyde in the wastewater can be lower than 200mg/L or even within 100mg/L, the formaldehyde is mainly converted into ketotriose, trialkanol and hexose, the biodegradability of the wastewater is improved, and the components are converted into low-molecular organic acid after anaerobic hydrolysis acidification, so that the low-molecular organic acid can be well utilized by aerobic microorganisms. In addition, nitrogen and phosphorus required by the growth of microorganisms are further supplemented by adding domestic sewage and supplementing nitrogen and phosphorus.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art according to these drawings.
FIG. 1 is a process flow diagram of an embodiment of the present invention;
FIG. 2 is a schematic diagram of a cooling system coupled with pH adjustment and temperature control.
Detailed Description
Reference will now be made in detail to exemplary embodiments of the present invention, the detailed description should not be construed as limiting the invention but rather as a more detailed description of certain aspects, features and embodiments of the invention.
It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Further, for numerical ranges in this disclosure, it is understood that each intervening value, between the upper and lower limit of that range, is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in that stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the documents are cited. In case of conflict with any incorporated document, the present specification will control.
It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The specification and examples are exemplary only.
As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including but not limited to.
The filler used in the following examples is a ZYZX series laminated open type microorganism carrier manufactured by Yao environmental protection industries, Inc. in Shanghai.
Chemical oxygen demand: COD;
suspended matters: SS;
total nitrogen: TN;
total phosphorus: TP;
total solids in solubility: TDS;
biochemical oxygen demand: BOD;
ammonia nitrogen: NH (NH)3-N。
Example 1
The process flow is shown in figure 1.
FIG. 2 is a schematic diagram of a cooling system coupled with pH adjustment and temperature control.
Polyoxymethylene wastewater in a workshop (comprising wastewater discharged from a production plant and wastewater in a polymerization zone with the total volume of 55m3H), the index concentrations are as follows: the COD concentration is 5900mg/L, the TP concentration is 10mg/L, the SS concentration is 385mg/L, TN (NH)3-N) concentration of 25mg/L, formaldehyde concentration of 1300mg/L, pH 4.18, temperature 25 ℃.
1. The polyformaldehyde wastewater enters an adjusting tank (in the wastewater treatment, the adjustment refers to homogenization, because the concentration of inlet water generally changes along with time, the water quality in the adjusting tank is homogenized and does not change so much after the inlet water stays for a period of time in the adjusting tank, and the water quantity is also adjusted and controlled through the adjusting tank) to be mixed, and after the inlet water stays for 24 hours, the mixture enters a polymerization reactor 1 to be polymerizedThe operation in the reactor 1 is as follows: adding catalyst Ca (OH) into the wastewater of polyformaldehyde production2Solution, Ca (OH)2The molar ratio of the solution to formaldehyde in the wastewater from polyformaldehyde production is 0.3:1, NaOH is used as alkali liquor to adjust the pH value to 10, and polymerization reaction is carried out at 55 ℃. The polymerization reactor 1 is provided with a stirring device, a pH probe and a temperature probe, the increase of the water temperature in the pool is obtained by introducing steam for heating, and when the temperature reaches a set value, the heating is stopped. The waste water stays in the reaction tank for 7 hours.
Then the wastewater enters a polymerization reactor 2, a stirring device is arranged in the reaction tank for mixing and stirring, no reagent is added, and the wastewater stays in the reaction tank for 7 hours.
2. In the embodiment, the pH adjusting tank uses a water collecting tank of a cooling tower, so that the reaction liquid treated in the previous step enters the cooling tower by using a lift pump for cooling and pH adjusting, the adding amount of phosphoric acid is determined to be 10kg/h according to the phosphorus content and the COD value in the wastewater, hydrochloric acid is automatically added according to the required pH, and the pH is controlled to be 8; the circulating water quantity of the cooling tower and the air draft of the axial flow fan are adjusted according to the water temperature in the water collecting tank of the cooling tower, and the water temperature is ensured to be lower than 37 ℃ when the polyformaldehyde production wastewater enters the biological selector.
3. The wastewater after pH neutralization and cooling enters a biological selector, the temperature of the wastewater is kept lower than 37 ℃, domestic sewage and initial rainwater of a plant area are introduced into the biological selector, the addition amount of urea is determined to be 40kg/h according to the nitrogen concentration and COD value in the wastewater, and the water amount of the domestic wastewater is 10m3H, initial rainwater 10m3And/h, finally keeping the weight ratio of COD to TN in the wastewater to be 20: 1;
the return sludge of the radial flow sedimentation tank also enters the biological selector, and the sludge reflux ratio is 0.5. The retention time of the wastewater in the biological selector is about 1.5 h.
4. The wastewater enters an anaerobic hydrolysis composite reactor, a filler is placed in the reactor, the filler adopts ZYZX biological carrier filler, totally 6 thousands of fillers are adopted, and the density is 60/m3The residence time was 19 h.
Then enters an aerobic composite reactor, an aeration device is paved in the reactor for oxygen supply, and the aeration device adopts micro-aerationA hole aerator for supplying oxygen to ensure that the aeration tank is in an aerobic condition, and fillers with the dosage of 10 ten thousand and the density of 60 fillers/m are placed in the reactor3The retention time is 32 h;
then the mixture enters a radial flow sedimentation tank for 0.5h of residence time;
then the mixture enters a high-efficiency coagulating sedimentation tank for sedimentation, and stays for 3.6 hours at the stage;
finally, the mixture enters a non-uniform Fenton oxidizer, iron-carbon granular filter materials are filled in the non-uniform Fenton oxidizer, and a hydrogen peroxide oxidizing agent is added into an inlet, wherein the adding amount of the iron-carbon granular filter materials is 75m3The amount of hydrogen peroxide added was 13kg/h, and the wastewater stayed in this stage for 1.0 h.
The effluent quality of each reaction unit is shown in table 1.
TABLE 1 Biochemical treatment design of sewage treatment plant for water quality main indexes of inlet water and outlet water
Figure BDA0003666100680000151
Figure BDA0003666100680000161
Note: the "-" part indicates that the detection at this stage was not performed.
As can be seen from Table 1, the method for treating wastewater from the production of polyoxymethylene, provided by the invention, can effectively remove formaldehyde content, the formaldehyde removal rate of the pretreatment section (to the cooling tower) reaches 96%, the formaldehyde removal rate of the whole process flow reaches 99.99%, and the content of pollutants in the wastewater is also effectively removed.
Comparative example 1
The same as example 1 except that Ca (OH)2Replacement of the solution by Mg (OH)2And (3) solution. The formaldehyde removal rate in the pretreatment stage (to the cooling tower) was 94%.
Comparative example 2
The difference from example 1 is that the NaOH solution is replaced by KOH solution. The formaldehyde removal rate in the pretreatment stage (to the cooling tower) was 96%.
The above description is intended to be illustrative of the present invention and should not be taken as limiting the invention, as the invention is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Claims (9)

1. A treatment method of wastewater from polyformaldehyde production is characterized by comprising the following steps:
the wastewater generated in the production of polyformaldehyde sequentially passes through a regulating tank, a polymerization reactor 1, a polymerization reactor 2, a pH adjusting tank, a cooling tower, a biological selector, an anaerobic hydrolysis composite reactor, an aerobic composite reactor, a radial flow type sedimentation tank, a high-efficiency coagulating sedimentation tank and a heterogeneous Fenton oxidation reactor, and water and sludge are discharged;
the polymerization reactor 1 was operated as follows: adding a catalyst into the wastewater from polyformaldehyde production, adjusting the pH value with an alkali liquor, stirring, and carrying out a polymerization reaction at 40-80 ℃.
2. The method for treating wastewater from production of polyoxymethylene according to claim 1, wherein the molar ratio of the catalyst to formaldehyde in wastewater from production of polyoxymethylene is (0.1-1): 1; the catalyst is an alkaline earth metal hydroxide.
3. The method for treating wastewater from polyoxymethylene production according to claim 1, wherein the alkali solution is an alkali metal hydroxide alkali solution; the pH is adjusted to be more than or equal to 9.
4. The method for treating wastewater from polyformaldehyde production according to claim 1, wherein a stirring device is provided in the polymerization reactor 2, the total of the stirring time and the stirring time of the polymerization reactor 1 is 3-14h, and the stirring time of the polymerization reactor 2 is not less than the stirring time of the polymerization reactor 1.
5. The method for treating wastewater from polyformaldehyde production according to claim 1, wherein an acid solution is added into the pH adjustment tank to adjust the pH to 7-8, wherein the addition amount is 1-4% of the mass of COD in wastewater from polyformaldehyde production.
6. The method for treating wastewater from polyoxymethylene production according to claim 1, wherein the cooling temperature of the cooling tower is set to 35 to 40 ℃ and the temperature of wastewater from polyoxymethylene production is ensured to be lower than 37 ℃ when entering the biological selector.
7. The method for treating wastewater from polyoxymethylene production according to claim 1, wherein a nitrogen source, miscellaneous wastewater and domestic sewage are added to the biological selector, and the discharged returned sludge is refilled into the biological selector.
8. The method for treating wastewater from polyformaldehyde production according to claim 1, wherein the anaerobic hydrolysis composite reactor adopts a hydraulic plug-flow mixing reaction mode, a plurality of mixing reactors are arranged along a water flow direction, power is provided to enable water to flow in a narrow and long channel in the reactor, water levels of an inlet and an outlet are kept consistent, and a filler is arranged in the reactor;
an aeration device is laid in the aerobic composite reactor and a filler is arranged in the aerobic composite reactor.
9. The method for treating wastewater from polyoxymethylene production according to claim 1, wherein the heterogeneous Fenton oxidation reactor is filled with an iron-carbon particulate filter, and a hydrogen peroxide oxidant is added at an inlet.
CN202210586365.1A 2022-05-27 2022-05-27 Treatment method of polyoxymethylene production wastewater Active CN114772871B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210586365.1A CN114772871B (en) 2022-05-27 2022-05-27 Treatment method of polyoxymethylene production wastewater

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210586365.1A CN114772871B (en) 2022-05-27 2022-05-27 Treatment method of polyoxymethylene production wastewater

Publications (2)

Publication Number Publication Date
CN114772871A true CN114772871A (en) 2022-07-22
CN114772871B CN114772871B (en) 2023-07-25

Family

ID=82408573

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210586365.1A Active CN114772871B (en) 2022-05-27 2022-05-27 Treatment method of polyoxymethylene production wastewater

Country Status (1)

Country Link
CN (1) CN114772871B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115231778A (en) * 2022-07-29 2022-10-25 杭州胜澜科技有限公司 Method for treating wastewater by polymethoxy dimethyl ether

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101671098A (en) * 2009-09-28 2010-03-17 上海中耀环保实业有限公司 Method of treating high-concentration metaformaldehyde waste water into reuse water
CN104108827A (en) * 2014-06-27 2014-10-22 李开明 Processing method for high concentration organic acid wastewater containing formaldehyde
CN105152483A (en) * 2015-09-14 2015-12-16 北京万邦达环保技术股份有限公司 Polyformaldehyde wastewater treatment device and wastewater treatment technique using device
CN204958682U (en) * 2015-09-14 2016-01-13 北京万邦达环保技术股份有限公司 Polyformaldehyde effluent treatment plant
CN112456716A (en) * 2020-12-06 2021-03-09 江苏金碧源环保科技有限公司 Pretreatment method of formaldehyde wastewater
CN113354154A (en) * 2021-06-30 2021-09-07 兖矿鲁南化工有限公司 Formaldehyde wastewater comprehensive treatment method and device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101671098A (en) * 2009-09-28 2010-03-17 上海中耀环保实业有限公司 Method of treating high-concentration metaformaldehyde waste water into reuse water
CN104108827A (en) * 2014-06-27 2014-10-22 李开明 Processing method for high concentration organic acid wastewater containing formaldehyde
CN105152483A (en) * 2015-09-14 2015-12-16 北京万邦达环保技术股份有限公司 Polyformaldehyde wastewater treatment device and wastewater treatment technique using device
CN204958682U (en) * 2015-09-14 2016-01-13 北京万邦达环保技术股份有限公司 Polyformaldehyde effluent treatment plant
CN112456716A (en) * 2020-12-06 2021-03-09 江苏金碧源环保科技有限公司 Pretreatment method of formaldehyde wastewater
CN113354154A (en) * 2021-06-30 2021-09-07 兖矿鲁南化工有限公司 Formaldehyde wastewater comprehensive treatment method and device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115231778A (en) * 2022-07-29 2022-10-25 杭州胜澜科技有限公司 Method for treating wastewater by polymethoxy dimethyl ether

Also Published As

Publication number Publication date
CN114772871B (en) 2023-07-25

Similar Documents

Publication Publication Date Title
KR101665636B1 (en) Wastewater pretreatment method and sewage treatment method using the pretreatment method
CN101522579B (en) Ozonation of wastewater for reduction of sludge or foam and bulking control
CN103613244B (en) Process for treating epoxy resin production wastewater
CN103466893B (en) Sewage recycling comprehensive treatment system
CN104609665A (en) Glyphosate-producing wastewater treatment integration technology
Farizoglu et al. Simultaneous removal of C, N, P from cheese whey by jet loop membrane bioreactor (JLMBR)
CN102107997A (en) Method for treating leachate of domestic waste incineration plants
KR20130111921A (en) Simultaneous anoxic biological phosphorus and nitrogen removal with energy recovery
CN105036462A (en) MVR technology-based machining emulsified wastewater treatment method
CA2909559A1 (en) Enhanced biosorption of wastewater organics using dissolved air flotation with solids recycle
CN106477816B (en) A kind of integrated treatment process of oxadiazon production waste water
CN112607963A (en) System and method for reducing percolate concentrated solution of waste incineration plant
CN111268872A (en) Pesticide wastewater treatment process and treatment device thereof
CN102786179A (en) Method for treatment and comprehensive utilization of high-concentration organic wastewater
CN114772871B (en) Treatment method of polyoxymethylene production wastewater
Yangin et al. A new process for the combined treatment of municipal wastewaters and landfill leachates in coastal areas
CN105712564A (en) Equipment for processing waste water through glyphosate production
CN102674621A (en) Method for treating high-concentration morpholine wastewater
El-Gohary et al. Cost-effective pre-treatment of food-processing industrial wastewater
CN102101740B (en) Treatment method of high-concentration organic wastewater in electronic industry
Kalyuzhnyi et al. Removal of chemical oxygen demand, nitrogen, and heavy metals using a sequenced anaerobic-aerobic treatment of landfill leachates at 10–30° C
CN112624500B (en) Kitchen waste sewage treatment system and method
CN112723653A (en) Garbage leachate full-scale harmless treatment method and system
US11352275B2 (en) High solids dissolved air flotation system and methods
CN113698022A (en) High-concentration formaldehyde wastewater treatment device and method

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant