CN110963634A - Advanced treatment method for papermaking wastewater - Google Patents

Advanced treatment method for papermaking wastewater Download PDF

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CN110963634A
CN110963634A CN201811156036.3A CN201811156036A CN110963634A CN 110963634 A CN110963634 A CN 110963634A CN 201811156036 A CN201811156036 A CN 201811156036A CN 110963634 A CN110963634 A CN 110963634A
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papermaking wastewater
wastewater
effluent
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enters
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黄振江
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Taishan Xianglong Paper Co Ltd
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Taishan Xianglong Paper Co Ltd
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    • 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
    • C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
    • 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
    • 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
    • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic 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
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
    • C02F1/56—Macromolecular 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
    • C02F1/72—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
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    • 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
    • C02F2101/34—Organic compounds containing oxygen
    • C02F2101/345—Phenols
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
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    • C02F2101/30—Organic compounds
    • C02F2101/38—Organic compounds containing nitrogen
    • 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
    • C02F2103/26—Nature of the water, waste water, sewage or sludge to be treated from the processing of plants or parts thereof
    • C02F2103/28—Nature of the water, waste water, sewage or sludge to be treated from the processing of plants or parts thereof from the paper or cellulose industry
    • 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
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/10—Solids, e.g. total solids [TS], total suspended solids [TSS] or volatile solids [VS]
    • 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
    • C02F2209/22—O2
    • 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
    • C02F2209/44—Time
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/04—Flow arrangements
    • C02F2301/046—Recirculation with an external loop
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/08—Multistage treatments, e.g. repetition of the same process step under different conditions
    • 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
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/02—Aerobic processes
    • C02F3/12—Activated sludge processes

Abstract

The invention discloses a method for deeply treating papermaking wastewater, which comprises the following steps: firstly, filtering papermaking wastewater by a grid and a twill filter screen in sequence, intercepting coarse fiber objects by using grid holes of an inclined screen, and simultaneously recovering fibers; then the filtered papermaking wastewater enters a Fenton reaction section, the Fenton reaction effluent enters a flocculation precipitation section, the mixed flocculant is added into the papermaking wastewater, and the mixture is subjected to standing reaction until a large amount of flocculation precipitates are separated out; and secondly, the effluent of the flocculation precipitation enters an aerobic biochemical section of a biochemical treatment unit, the effluent of the aerobic biochemical section enters a secondary sedimentation tank, and finally the effluent is treated by a fiber filter and can be discharged after reaching the standard. The Fenton reaction section treatment effect of the papermaking wastewater advanced treatment method is good and stable, the pickling waste liquid is recycled, and secondary pollution is avoided; meanwhile, the treatment method is simple in operation, low in cost and free of byproducts, and is a treatment process with wide applicability and high treatment efficiency.

Description

Advanced treatment method for papermaking wastewater
Technical Field
The invention belongs to the technical field of water treatment, and particularly relates to a papermaking wastewater advanced treatment method.
Background
The papermaking wastewater refers to wastewater generated in the pulping and papermaking process. Comprises pulping and cooking waste liquor, washing waste water, bleaching waste water, paper machine white water and the like. The papermaking wastewater contains a large amount of organic matters and suspended matters, and also contains a large amount of chemicals and impurities, is complex in composition and poor in biodegradability, belongs to industrial wastewater which is difficult to treat, and is one of main industrial pollution sources in China.
The existing papermaking sewage treatment technology generally adopts the technology of combining physical and chemical treatment, biochemical treatment and physical and chemical treatment, so that the wastewater reaches the discharge standard. However, the wastewater treated by the existing treatment technology has many indexes which do not meet the requirements of relevant water pollutant discharge standards, so that the water quality which does not reach the standard is discharged into the water body, the purification burden of the water body is increased, the environmental pollution events such as river and lake stink, fish and shrimp death and the like are caused, and a large amount of water resources are wasted.
Disclosure of Invention
The invention aims to overcome the defects that the waste water treatment of the existing paper making enterprises is difficult and the water quality is difficult to reach the standard, and provides a method for deeply treating the paper making waste water.
The technical scheme of the invention is as follows: a method for deeply treating papermaking wastewater comprises the following steps:
(1) filtering the papermaking wastewater by a grid and a twill filter screen in sequence, intercepting coarse fiber objects by using grid holes of an inclined screen, and simultaneously recovering fibers;
(2) the papermaking wastewater filtered in the step (1) enters a Fenton reaction section, and acid pickling waste liquid and hydrogen peroxide are added into the papermaking wastewater, and the mixed liquid of the acid pickling waste liquid, the hydrogen peroxide and the papermaking wastewater is subjected to a Fenton reaction; breaking bonds and opening rings of lignin, hemilignin, cellulose and other macromolecular organic matters in the papermaking wastewater to form micromolecular organic matters, and oxidizing and decomposing part of the micromolecular organic matters in the wastewater to generate colloidal suspended matters;
(3) the Fenton reaction effluent treated in the step (2) enters a flocculation precipitation section, a mixed flocculant is added into the papermaking wastewater, and the mixture is subjected to standing reaction until a large amount of flocculation precipitates are separated out;
(4) the effluent of the flocculation precipitation treated in the step (3) enters an aerobic biochemical section of a biochemical treatment unit, the hydraulic retention time of the aerobic biochemical section is 7.2-9.1 h, the sludge concentration is 3-4 g/L, and the dissolved oxygen is 2-4 mg/L;
(5) the effluent of the aerobic biochemical section treated in the step (4) enters a secondary sedimentation tank, the sedimentation time is 1.5-2 h, and the surface load isIs 0.8 to 1.0m3/m2·h；
(6) And (5) treating the effluent of the secondary sedimentation tank treated in the step (5) by a fiber filter, and discharging the effluent after reaching the standard.
Further, the papermaking wastewater advanced treatment method also comprises an excess sludge tank and a sludge press filtration device, wherein precipitates generated by the grating, the twill filter screen, the flocculation precipitation section and the secondary sedimentation tank are collected and stored in the excess sludge tank, and then the precipitates are concentrated by the sludge press filtration device to generate dry sludge and sludge press filtration liquid; and (3) refluxing the sludge press filtrate into an aerobic biochemical section for further deep treatment, and transporting the dry sludge outside for disposal.
Further, the pickling waste liquid in the step (2) is black or yellow-black iron-containing acidic liquid, the pH value of the iron-containing acidic liquid is 1.0-2.0, the total iron mass fraction of the iron-containing acidic liquid is 15% -20%, and the density of the iron-containing acidic liquid is about 1.3g/cm3。
Further, when the pickling waste liquid, the hydrogen peroxide and the papermaking wastewater are mixed in the step (2), the adding amount of the pickling waste liquid is about 500 mg/L; the mass fraction of the hydrogen peroxide is more than or equal to 30%, and the adding amount is 45-55 mg/L.
Further, the mixed flocculant in the step (3) is a mixture of polyaluminium chloride and polyacrylamide; the adding amount of the polyaluminium chloride is 0.1-0.5% of the weight of the wastewater, and the adding amount of the polyacrylamide is 0.05-0.15% of the weight of the wastewater.
Further, the diameter of the fiber filter in the step (6) is 3000 mm.
Further, when the fiber filter filters in the step (6), the flow rate of the wastewater is controlled to be 100m3The flow rate was 150 m/h.
Further, the grid size of the twill filter screen in the step (1) is 100-120 meshes.
Compared with the prior art, the method for deeply treating the papermaking wastewater has the following advantages: 1) the Fenton reaction section has good and stable treatment effect, the removal rate of COD (chemical oxygen demand) of the papermaking wastewater can reach more than 40 percent after the treatment process, the chroma dilution multiple is reduced from about 150 times to about 30 times, and the COD of the effluent can be ensured to be stably below 50mg/L and be stably less than 30 times through subsequent flocculation precipitation, aerobic biochemical treatment, secondary precipitation and biochemical treatment processes, and other effluent indexes also meet the first-level A standard in the pollutant discharge standard of urban sewage treatment plants (GB 18918-2002); 2) the filtering speed of the fiber filter is more than 150m/h, which is more than 10 times of that of the common rapid filter, thereby saving a large amount of floor space; 3) the invention utilizes the pickling waste liquid as resources, provides necessary iron ions and hydrogen ions for counteracting the high alkalinity of raw water for Fenton-like reaction, avoids potential environmental risks brought by the pickling waste liquid, treatment cost and secondary pollution generated by the treatment of the pickling waste liquid, and avoids the waste of acid and iron resources; 4) meanwhile, the treatment process is simple in operation and low in cost, does not generate byproducts, does not pollute the environment, and is a treatment process which has wide applicability and high treatment efficiency and can effectively and deeply treat the papermaking wastewater.
For a better understanding and practice, the present invention is described in detail below.
Drawings
FIG. 1 is a process flow diagram of the advanced treatment method of papermaking wastewater according to the invention.
Detailed Description
Referring to the attached drawings, fig. 1 is a process flow diagram of the advanced treatment method of papermaking wastewater according to the present invention. The related wastewater treatment process comprises physical grating, filtration, Fenton reaction, flocculation and precipitation, aerobic biochemistry, fiber filtration and the like, and the related processes are as follows:
fenton reactionIs an inorganic chemical reaction, the reaction process is approximately hydrogen peroxide (H)2O2) The mixed solution with the ferrous ion Fe oxidizes many known organic compounds such as carboxylic acids, alcohols, esters into an inorganic state. The reaction has high capability of removing organic pollutants which are difficult to degrade, and is widely applied to the treatment of printing and dyeing wastewater, oily wastewater, phenol-containing wastewater, coking wastewater, nitrobenzene-containing wastewater, diphenylamine wastewater and other wastewater. The specific involved chemical reactions are as follows:
Fe2++H2O2→Fe3++(OH)-+OH· ①
H2O2+Fe3+→Fe2++O2+2H+②
O2+Fe2+→Fe3++O2③
as can be seen from the above reaction formula, the Fenton's reagent generates 1 mol of OH.free radical and also 1 mol of peroxy radical O2However, since the oxidation potential of peroxy radicals is only about 1.3V, OH radicals are the main oxidizing species in Fenton's reagent.
The pickling waste liquid used by the method is black or yellow-black iron-containing acidic liquid for resource utilization, provides necessary iron ions and hydrogen ions for counteracting the high alkalinity of raw water for Fenton-like reaction, avoids potential environmental risks brought by the pickling waste liquid and treatment cost and secondary pollution generated by treating the pickling waste liquid, and simultaneously avoids waste of acid and iron resources.
Flocculation precipitationIs the process of flocculation and precipitation of particles in water. After a coagulant is added into water, colloids and dispersed particles of suspended matters generate floccules under the interaction of molecular force, and the floccules collide with each other and are condensed in the sedimentation process, so that the size and the mass of the floccules are continuously increased, and the sedimentation speed is continuously increased. Alum floc formed after coagulant is added into ground water, organic suspended matters in domestic sewage and activated sludge are flocculated and precipitated in the precipitation process.
Aerobic biochemical treatmentThe treatment refers to a biochemical process of degrading and converting organic matters into humus-like substances under the conditions of proper carbon-nitrogen ratio, water content, oxygen and the like in the presence of microorganisms. The aerobic biochemical treatment mainly depends on the biochemical actions of aerobic bacteria and facultative anaerobic bacteria to complete the process of the treatment process. The action mechanism is a method for degrading organic matters by mainly using aerobic microorganisms on the premise of providing free oxygen. Has the advantages of high reaction speed, short reaction time and no generation of malodor in the reaction process.
FiberFilterThe series of filters take a rotary-wing type fiber filter material as a technical core. The rotary wing type fiber filter material has the advantages of high backwashing cleanliness of the granular filter material, and low water consumption of backwashing and primary filtration water; the advantages of large specific surface area of the fiber filter material, high filtering precision, large pollutant interception capacity and high clearance of the filter bed are also achieved; meanwhile, the device has the characteristics of strong capability of adapting to different media, good backwashing effect and high utilization rate of the filter bed.
During filtration, the rotor type fiber filter material forms the nearly ideal filter bed that the pore from top to bottom is big-end-up gradient change distribution in the filter, and this structure of filter bed is favorable to the effective separation of aquatic suspended solid, and big suspended solid will be held back on upper portion, and little suspended solid that fails to be held back will descend, because the gap of filter bed diminishes gradually, must be held back in the lower part. So that the filter bed formed by the rotary wing type fiber filter material in the filter not only has high precision of filtration, but also has high filtration speed of filtration. When the filter is backwashed, under the strong impact of water flow and air flow, the filter bed expands, the filter material floats upwards, the fiber tows gradually take a fluffy state, and because the rotor wing is arranged on the rotor wing type fiber filter material, the rotor wing drives the fiber tows to do insufficient rotation, swinging and mutual impact, thereby greatly accelerating the separation of suspended particles attached on the fiber tows, improving the cleaning speed of the filter material, saving the water consumption of backwashing and saving the energy of backwashing.
Example 1
Taking the COD of the pollutants as 1120mg/L, BOD5The papermaking wastewater with 340mg/L, SS 960mg/L and 154 times of chroma enters a physicochemical treatment unit, coarse fiber objects are intercepted by using grid holes of an inclined screen, fibers are recycled at the same time, and the grid size is 120 meshes; then the mixture enters a Fenton reaction section, and the iron-containing acidic liquid with the pH value of 1.0 and the total iron mass fraction of 18 percent is added, wherein the density of the iron-containing acidic liquid is about 1.3g/cm3The adding amount of the pickling waste liquid is about 500 mg/L; the dosage of the hydrogen peroxide is 50 mg/L.
The mixed solution of the pickling waste liquid, the hydrogen peroxide and the papermaking wastewater generates a Fenton reaction; breaking bonds and opening rings of lignin, hemilignin, cellulose and other macromolecular organic matters in the papermaking wastewater to form micromolecular organic matters, and oxidizing and decomposing part of the micromolecular organic matters in the wastewater to generate colloidal suspended matters;
the effluent after Fenton reaction enters a flocculation precipitation section, polyaluminium chloride accounting for 0.3 percent of the weight of the wastewater and polyacrylamide accounting for 0.10 percent of the weight of the wastewater are added into the papermaking wastewater, and the mixture is kept stand for reaction until a large amount of flocculation precipitates are separated out; the effluent after flocculation precipitation enters an aerobic biochemical section of a biochemical treatment unit, aeration is kept, the hydraulic retention time is 8.2 hours, the sludge concentration is 3.5g/L, and the dissolved oxygen is 3 mg/L; the effluent from the aerobic biochemical section enters a secondary sedimentation tank, the sedimentation time is 1.8h, and the surface load is 0.9m3/m2H; the effluent of the secondary sedimentation tank is treated by a fiber filter, the diameter of the fiber filter is 3000mm, and the flow of the wastewater is controlled to be 100m3Flow rate of 150m/h, COD of effluent 42.6mg/L, BOD58.3mg/L, 9.6mg/L SS and 28 times chroma, and the standard emission can be achieved.
Collecting sediments generated by the grating, the twill filter screen, the flocculation precipitation section and the secondary sedimentation tank, storing the sediments in a residual sludge tank, and concentrating the sediments by a sludge filter pressing device to generate dry sludge and sludge filter pressing liquid; and (3) refluxing the sludge press filtrate into an aerobic biochemical section for further deep treatment, and transporting the dry sludge outside for disposal.
Example 2
Taking the COD of the pollutants as 1050mg/L and BOD5The papermaking wastewater with the concentration of 360mg/L, the SS of 1000mg/L and the chromaticity of 146 times enters a physicochemical treatment unit, coarse fiber objects are intercepted by using grid holes of an inclined screen, fibers are recycled at the same time, and the grid size is 100 meshes; then the mixture enters a Fenton reaction section, and the iron-containing acidic liquid with the pH value of 2.0 and the total iron mass fraction of 15 percent is added, wherein the density of the iron-containing acidic liquid is about 1.3g/cm3The adding amount of the pickling waste liquid is about 500 mg/L; the dosage of the hydrogen peroxide is 45 mg/L.
The mixed solution of the pickling waste liquid, the hydrogen peroxide and the papermaking wastewater generates a Fenton reaction; breaking bonds and opening rings of lignin, hemilignin, cellulose and other macromolecular organic matters in the papermaking wastewater to form micromolecular organic matters, and oxidizing and decomposing part of the micromolecular organic matters in the wastewater to generate colloidal suspended matters;
the effluent after Fenton reaction enters a flocculation precipitation section, polyaluminium chloride accounting for 0.1 percent of the weight of the wastewater and polyacrylamide accounting for 0.15 percent of the weight of the wastewater are added into the papermaking wastewater, and the mixture is kept stand for reaction until a large amount of flocculation precipitates are separated out; the effluent after flocculation precipitation enters an aerobic biochemical section of a biochemical treatment unit, aeration is kept, the hydraulic retention time is 9.1h, the sludge concentration is 3.0g/L, and the dissolved oxygen is 4 mg/L; the effluent from the aerobic biochemical section enters a secondary sedimentation tank, the sedimentation time is 1.5h, and the surface load is 1.0m3/m2H; the effluent of the secondary sedimentation tank is treated by a fiber filter, the diameter of the fiber filter is 3000mm, and the flow of the wastewater is controlled to be 100m3Flow rate of 150m/h, COD of effluent of 40.1mg/L, BOD59.0mg/L, 8.9mg/L SS and 27 times chroma, and the standard emission can be achieved.
Collecting sediments generated by the grating, the twill filter screen, the flocculation precipitation section and the secondary sedimentation tank, storing the sediments in a residual sludge tank, and concentrating the sediments by a sludge filter pressing device to generate dry sludge and sludge filter pressing liquid; and (3) refluxing the sludge press filtrate into an aerobic biochemical section for further deep treatment, and transporting the dry sludge outside for disposal.
Example 3
Taking the COD of the pollutants as 980mg/L, BOD5The papermaking wastewater with the concentration of 310mg/L, SS of 920mg/L and chroma of 151 times enters a physicochemical treatment unit, coarse fiber objects are intercepted by using grid holes of an inclined screen, fibers are recycled at the same time, and the grid size is 110 meshes; then the mixture enters a Fenton reaction section, and the iron-containing acidic liquid with the pH value of 1.5 and the total iron mass fraction of 20 percent is added, wherein the density of the iron-containing acidic liquid is about 1.3g/cm3The adding amount of the pickling waste liquid is about 500 mg/L; the dosage of the hydrogen peroxide is 55 mg/L.
The mixed solution of the pickling waste liquid, the hydrogen peroxide and the papermaking wastewater generates a Fenton reaction; breaking bonds and opening rings of lignin, hemilignin, cellulose and other macromolecular organic matters in the papermaking wastewater to form micromolecular organic matters, and oxidizing and decomposing part of the micromolecular organic matters in the wastewater to generate colloidal suspended matters;
by Fenton reactionThe effluent enters a flocculation precipitation section, polyaluminium chloride accounting for 0.5 percent of the weight of the wastewater and polyacrylamide accounting for 0.05 percent of the weight of the wastewater are added into the papermaking wastewater, and the mixture is kept stand for reaction until a large amount of flocculation precipitates are separated out; the effluent after flocculation precipitation enters an aerobic biochemical section of a biochemical treatment unit, aeration is kept, the hydraulic retention time is 7.2 hours, the sludge concentration is 4g/L, and the dissolved oxygen is 3.5 mg/L; the effluent from the aerobic biochemical section enters a secondary sedimentation tank, the sedimentation time is 2 hours, and the surface load is 0.8m3/m2H; the effluent of the secondary sedimentation tank is treated by a fiber filter, the diameter of the fiber filter is 3000mm, and the flow of the wastewater is controlled to be 100m3Flow rate of 150m/h, COD of effluent of 45.1mg/L, BOD59.2mg/L, SS 8.4mg/L and 29 times of chroma, thus reaching the discharge standard.
Collecting sediments generated by the grating, the twill filter screen, the flocculation precipitation section and the secondary sedimentation tank, storing the sediments in a residual sludge tank, and concentrating the sediments by a sludge filter pressing device to generate dry sludge and sludge filter pressing liquid; and (3) refluxing the sludge press filtrate into an aerobic biochemical section for further deep treatment, and transporting the dry sludge outside for disposal.
Compared with the prior art, the method for deeply treating the papermaking wastewater has the following advantages: 1) the Fenton reaction section has good and stable treatment effect, the removal rate of COD (chemical oxygen demand) of the papermaking wastewater can reach more than 40 percent after the treatment process, the chroma dilution multiple is reduced from about 150 times to about 30 times, and the COD of the effluent can be ensured to be stably below 50mg/L and be stably less than 30 times through subsequent flocculation precipitation, aerobic biochemical treatment, secondary precipitation and biochemical treatment processes, and other effluent indexes also meet the first-level A standard in the pollutant discharge standard of urban sewage treatment plants (GB 18918-2002); 2) the filtering speed of the fiber filter is more than 150m/h, which is more than 10 times of that of the common rapid filter, thereby saving a large amount of floor space; 3) the invention utilizes the pickling waste liquid as resources, provides necessary iron ions and hydrogen ions for counteracting the high alkalinity of raw water for Fenton-like reaction, avoids potential environmental risks brought by the pickling waste liquid, treatment cost and secondary pollution generated by the treatment of the pickling waste liquid, and avoids the waste of acid and iron resources; 4) meanwhile, the treatment process is simple in operation and low in cost, does not generate byproducts, does not pollute the environment, and is a treatment process which has wide applicability and high treatment efficiency and can effectively and deeply treat the papermaking wastewater.
The present invention is not limited to the above-described embodiments, and various modifications and variations of the present invention are intended to be included within the scope of the claims and the equivalent technology of the present invention if they do not depart from the spirit and scope of the present invention.

Claims (8)

1. The advanced treatment method of the papermaking wastewater is characterized by comprising the following steps:
(1) filtering the papermaking wastewater by a grid and a twill filter screen in sequence, intercepting coarse fiber objects by using grid holes of an inclined screen, and simultaneously recovering fibers;
(2) the papermaking wastewater filtered in the step (1) enters a Fenton reaction section, and acid pickling waste liquid and hydrogen peroxide are added into the papermaking wastewater, and the mixed liquid of the acid pickling waste liquid, the hydrogen peroxide and the papermaking wastewater is subjected to a Fenton reaction; breaking bonds and opening rings of lignin, hemilignin, cellulose and other macromolecular organic matters in the papermaking wastewater to form micromolecular organic matters, and oxidizing and decomposing part of the micromolecular organic matters in the wastewater to generate colloidal suspended matters;
(3) the Fenton reaction effluent treated in the step (2) enters a flocculation precipitation section, a mixed flocculant is added into the papermaking wastewater, and the mixture is subjected to standing reaction until a large amount of flocculation precipitates are separated out;
(4) the effluent of the flocculation precipitation treated in the step (3) enters an aerobic biochemical section of a biochemical treatment unit, the hydraulic retention time of the aerobic biochemical section is 7.2-9.1 h, the sludge concentration is 3-4 g/L, and the dissolved oxygen is 2-4 mg/L;
(5) the effluent of the aerobic biochemical section treated in the step (4) enters a secondary sedimentation tank, the sedimentation time is 1.5-2 h, and the surface load is 0.8-1.0 m3/m2·h；
(6) And (5) treating the effluent of the secondary sedimentation tank treated in the step (5) by a fiber filter, and discharging the effluent after reaching the standard.
2. The advanced treatment method of papermaking wastewater according to claim 1, characterized in that: the advanced treatment method of the papermaking wastewater also comprises an excess sludge tank and a sludge press filtration device, wherein precipitates generated by the grating, the twill filter screen, the flocculation precipitation section and the secondary sedimentation tank are collected and stored in the excess sludge tank, and then the precipitates are concentrated by the sludge press filtration device to generate dry sludge and sludge press filtrate; and (3) refluxing the sludge press filtrate into an aerobic biochemical section for further deep treatment, and transporting the dry sludge outside for disposal.
3. The advanced treatment method of papermaking wastewater according to claim 1, characterized in that: the pickling waste liquid in the step (2) is black or yellow-black iron-containing acidic liquid, the pH value of the iron-containing acidic liquid is 1.0-2.0, the total iron mass fraction of the iron-containing acidic liquid is 15% -20%, and the density of the iron-containing acidic liquid is about 1.3g/cm3。
4. The method for the advanced treatment of papermaking wastewater according to claim 3, characterized in that: when the pickling waste liquid, the hydrogen peroxide and the papermaking wastewater are mixed in the step (2), the adding amount of the pickling waste liquid is about 500 mg/L; the mass fraction of the hydrogen peroxide is more than or equal to 30%, and the adding amount is 45-55 mg/L.
5. The advanced treatment method of papermaking wastewater according to claim 1, characterized in that: the mixed flocculant in the step (3) is a mixture of polyaluminium chloride and polyacrylamide; the adding amount of the polyaluminium chloride is 0.1-0.5% of the weight of the wastewater, and the adding amount of the polyacrylamide is 0.05-0.15% of the weight of the wastewater.
6. The advanced treatment method of papermaking wastewater according to claim 1, characterized in that: the diameter of the fiber filter in the step (6) is 3000 mm.
7. The method for the advanced treatment of papermaking wastewater according to claim 1, characterized in that: controlling the flow of the wastewater to be 100m when the fiber filter filters in the step (6)3The flow rate was 150 m/h.
8. The advanced treatment method of papermaking wastewater according to claim 1, characterized in that: the grid size of the twill filter screen in the step (1) is 100-120 meshes.
CN201811156036.3A 2018-09-30 2018-09-30 Advanced treatment method for papermaking wastewater Withdrawn CN110963634A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111517421A (en) * 2020-04-23 2020-08-11 南京大学 Method for improving iron-carbon micro-electrolysis reaction efficiency by using iron-containing waste acid liquor wastewater
CN111825274A (en) * 2020-07-08 2020-10-27 宁波神筹环保设备有限公司 Industrial park comprehensive sewage advanced treatment device and method
CN113997368A (en) * 2021-10-29 2022-02-01 广西金桂浆纸业有限公司 Wood chip treatment method and wood chip treatment system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111517421A (en) * 2020-04-23 2020-08-11 南京大学 Method for improving iron-carbon micro-electrolysis reaction efficiency by using iron-containing waste acid liquor wastewater
CN111825274A (en) * 2020-07-08 2020-10-27 宁波神筹环保设备有限公司 Industrial park comprehensive sewage advanced treatment device and method
CN113997368A (en) * 2021-10-29 2022-02-01 广西金桂浆纸业有限公司 Wood chip treatment method and wood chip treatment system

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