CN103241912B - Method for treating tobacco sheet production wastewater - Google Patents

Abstract

A method for treating waste water generated in tobacco sheet production comprises the following steps: waste water from tobacco sheet production → deslagging → chemical decalcification → anaerobic treatment → electrolysis → A/O treatment → secondary electrolysis → MBR → electrolytic disinfection → discharge after reaching standards. The method disclosed by the invention is based on the combination of a chemical decalcification technology, a biochemical technology, an electrochemical technology and an MBR technology, effectively treats the tobacco sheet production wastewater, and is low in cost, high in efficiency and capable of reaching the wastewater discharge standard.

Description

A treatment method for waste water from tobacco sheet production

technical field

The present invention relates to a treatment method for tobacco sheet production wastewater, in particular to a treatment method for tobacco sheet production wastewater and tobacco production wastewater based on chemical decalcification technology, biochemical technology, electrochemical technology and MBR technology, which belongs to environmental engineering in the field of water pollution control. the

Background technique

During the production of tobacco leaves, the raw materials cannot be fully utilized. During the production process of tobacco from primary processing to cigarette production, there will be scraps accounting for about 1/3 of the total amount of raw tobacco materials. These tobacco scraps cannot be directly used as The raw material is again made into a cigarette product. In order to reduce the generation of waste and realize the comprehensive utilization of debris, tobacco sheet technology came into being. Tobacco sheet, also known as reconstituted tobacco (Reconstituted Tobacco), is a regenerated product made of tobacco materials such as tobacco dust, tobacco stems, and shredded tobacco pieces as raw materials, which are used as cigarette fillers to reduce tar in cigarettes content, reduce the health hazards of smoking to the human body. The use of tobacco sheets has many advantages such as improving the quality of shredded tobacco, reducing the cost of cigarettes, saving raw material consumption, and reusing resources. Rolling method, thick pulp method and papermaking method are the main production methods of tobacco sheet at present. Compared with roll-pressing and thick-pulp flakes, paper-making flakes have obvious advantages: reduced cigarette production costs, stable product quality, high filling value and filamentation rate, good mechanical processing resistance, improved cigarette burning speed and It reduces the amount of tar release, has high plasticity and is easier to process. It is an effective process for producing "healthy" cigarettes at present. It is precisely because the papermaking sheet has the incomparable advantages of the rolling method and the thick stock method, so it has been widely promoted at home and abroad.

The wastewater produced during the production of paper-making tobacco flakes has the common characteristics of papermaking wastewater such as a large amount of fiber, and tobacco wastewater has high color, poor biodegradability, and nicotine and calcium and magnesium content that are unfavorable to microbial growth. High 150 ~ 500mg/L and other characteristics, the main pollution indicators are as follows:

At the same time, the concentration of wastewater fluctuates greatly, CODcr is from 1500 to 25000mg/L, SS is from 1000 to 15000mg/L, nicotine and tar inhibit the growth of microorganisms, and the high content of calcium and magnesium leads to fouling of the reactor and cannot operate normally. waste water.

Chinese patent CN1683261A discloses a method for treating waste water from tobacco flake production by papermaking, namely coagulation air flotation + aerobic oxidation + mechanical filtration tobacco flake production wastewater.

Chinese patent CN102276093A discloses a method for treating waste water from the production of paper-making tobacco flakes. The process includes the following steps: passing the production waste water through a grid for coarse filtration, and flowing into the waste water regulating tank by gravity; lifting the waste water in the waste water regulating tank to the mixed Add Ca-diatomaceous earth composite coagulant to the condenser to react for 5-10min, then add polyferric sulfate and polyacrylamide separation agent into the static reaction tank for reaction, the reaction time is 50-60min; low-concentration organic wastewater After adjusting the pH to be acidic, it is pumped into the ultrasonic micro-electrolysis reactor, and through the joint reaction of ultrasonic and micro-electrolysis, the chemical oxygen-consuming substances in the wastewater are quickly digested, and the reaction time is 30-60min; then the wastewater is adsorbed by activated carbon and quartz Sand filtration; the sludge produced in the adjustment tank and static reaction tank section is used as solid fuel after dehydration of screw stack sludge.

Chinese patent CN10133045A discloses that the waste water from the production of tobacco flakes by the papermaking method is reused in the pulping section after one to three stages of filtration, and the reused water is regularly discharged to the sewage treatment station. affect the quality of the flakes.

Chinese patent CN1683261A discloses a method in which wastewater from papermaking tobacco sheet production is first coagulated and air flotation is used to remove suspended solids, and then sent to an aeration tank to remove most of the COD substances through aerobic microorganisms.

The above methods have a certain effect on the treatment of tobacco sheet production wastewater, but there are defects such as long process flow, large equipment investment, large floor space, and high operating costs. What is more serious is that the wastewater contains a large amount of calcium, which directly leads to biochemical The treatment system and the membrane separation system are massively fouled, and the system cannot operate normally. The discharged wastewater treated by the existing wastewater treatment technology cannot meet the discharge standard.

Contents of the invention

The purpose of the present invention is to aim at the long process flow, large equipment investment, large floor area, high operating cost, and biochemical treatment system and membrane treatment system that cannot operate normally due to fouling in the existing tobacco production wastewater treatment method. The treated wastewater does not meet the standard and other defects, and provides a treatment based on the combination of chemical decalcification technology, biochemical technology, electrochemical technology and MBR technology, with low cost and high efficiency, so that it can meet the standard discharge of tobacco production wastewater method.

A kind of treatment method of tobacco sheet production waste water of the present invention comprises the following steps:

(1) Slag removal

Tobacco sheet production wastewater is collected by pipelines and discharged into the mechanical coarse grid sump. Coarse grids are set in the pool to isolate and remove the coarse floating matter in the sewage to prevent subsequent processing equipment from being blocked. Then, the tobacco is discharged through the lifting pump. The waste water from sheet production is lifted into the rotary mechanical grille machine, and most of the insoluble suspended solids in the water are further removed through the filtration of the filter screen. Large particle fibers and other suspended matter are separated, which greatly reduces the processing load of subsequent processes.

(2) Chemical decalcification

The effluent from the air flotation tank flows into the first-level decalcification reaction tank through the pipeline, and first adds an appropriate amount of lime saturated clear solution to adjust the pH value to 8.5-9.5 through the dosing device under stirring. After removing the false hardness (bicarbonate), it flows into the second-level The decalcification reaction tank is fed with the gas generated in the UASB anaerobic tank in step (3) anaerobic treatment, so that CO ₂ in the gas reacts with calcium and magnesium ions to form carbonate precipitation, or add 100~400mg/L Na ₂ CO _3. Make the carbonate radical react with calcium and magnesium ions to form carbonate precipitation. After the effluent flows into the coagulation tank, add 5~10mg/L FeSO ₄ under stirring conditions, and then add Na ₂ CO ₃ to reverse the pH value to 8~9. , and finally add 2~3mg/L polyphenylene amide (PAM), after the reaction is complete, enter the primary sedimentation tank for precipitation and separation, so as to remove calcium and magnesium ions in tobacco treatment wastewater, with a removal rate of 50~90%, reducing water Hardness, so that Ca ²⁺ is lower than 50 mg/L, preventing subsequent equipment and facilities from scaling due to excessive Ca ²⁺ ; the sediment (sludge) in the primary settling tank is sent to the sludge tank through pumps and pipes In the sludge dehydration unit, the filtration and separation are carried out at last, and the calcium carbonate is recovered, and the effluent from the primary sedimentation tank enters the adjustment tank.

(3) Anaerobic treatment

The effluent from the adjustment tank is lifted to the hydrolytic acidification tank by the lifting pump, and stays in the hydrolytic acidification tank for a certain period of time. The macromolecular organic matter in the wastewater is hydrolyzed and acidified into small molecular organic acids by acid-producing bacteria under the action of the acid-producing bacteria, and then passed through the lifting pump. After entering the UASB anaerobic pool, organic acids are decomposed into methane and carbon dioxide under the combined action of anaerobic and facultative bacteria adsorption, fermentation, and methanogenicity in the UASB anaerobic pool, and the B/C value of wastewater is improved through anaerobic treatment. Improve the biodegradability of wastewater; the generated methane and carbon dioxide are collected by the gas collection device and then introduced into the second decalcification reaction tank in step (2) chemical decalcification to remove carbon dioxide, hydrogen sulfide, and mercaptan impurities in the biogas, and purify Finally, the biogas is recovered in the gas storage tank; the waste water enters step (4).

(4) Electrolysis

The effluent from the UASB anaerobic tank enters the electrolysis machine a for electrolysis to remove color and odor, and at the same time make the difficult-to-biochemical macromolecular compounds in the wastewater open and break the chain to become biochemical small molecules, further increasing the B/C value. The conditions for subsequent biochemical treatment are improved; the voltage between two adjacent electrodes of the electrolysis machine is 2-12V, and the current density is 10-320mA/cm ² .

(5) A/O processing

The effluent from electrolysis enters the anoxic tank, the aerobic tank and the intermediate sedimentation tank in sequence, and part of the sludge in the intermediate sedimentation tank is returned to the anoxic tank through the return pump, and nitrogen and phosphorus can be removed under the alternating action of anoxic and aerobic microorganisms , and further oxidize and decompose the organic matter in the wastewater through aerobic treatment, and deeply remove COD and BOD; the aerobic pool is evenly filled with a large number of biological suspension fillers to provide habitat, growth and reproduction places for aerobic microorganisms, so that microorganisms can form on the filler surface biofilm. There is an aeration and oxygenation mixing system at the bottom of the aerobic tank to oxygenate the sewage to maintain the dissolved oxygen in the water at 2-4 mg/L, and at the same time, use the effect of gas rise to make the suspended solids in the tank and the water closer. Adequate contact, in addition, through the agitation of gas and water backwashing, can effectively wash away the aging biofilm growing on the surface of the filler, promote the replacement of the biofilm, and maintain a high activity of the biofilm.

(6) Secondary electrolysis

The effluent from the middle sedimentation tank enters the electrolysis machine b again for electrolysis, so that the macromolecular organic matter that is difficult to biochemically undergoes electrolysis to open the ring and break the chain, and converts it into small molecular organic matter that is easy to biochemically, improving B/C; during electrolysis, two adjacent electrodes The voltage between them is 2-6V, and the current density is 20-200mA/cm ² .

(7) MBR processing

The effluent from the secondary electrolysis enters the MBR system, which performs biochemical and membrane separation on the wastewater, degrades the remaining organic pollutants and removes suspended solids.

(8) Disinfection

After the wastewater is treated by MBR, the effluent is then treated by an electrolytic disinfection tank, which can further remove the chroma, and sterilize the wastewater, and finally discharge it up to the standard.

(9) Sludge treatment

The sludge generated in step (3) UASB anaerobic tank in anaerobic treatment, anoxic tank, aerobic tank and middle sedimentation tank in step (5) A/O treatment, and step (7) MBR treatment all enter the sludge through pipelines pool, and then through the dehydration of the sludge filter press to reduce the volume of the sludge, after dehydration, the mud cake is incinerated, and the filtrate is returned to the regulating pool in step (2) chemical decalcification.

The air flotation mentioned in the step (1) of slag removal is one of the air distribution air flotation method, electric flotation method, biological and chemical air flotation method, and dissolved air flotation method.

Step (2) The second step of chemical decalcification is to pass the biogas (containing methane, carbon dioxide, hydrogen sulfide, mercaptans, ammonia, etc.) generated by the UASB anaerobic tank to the secondary decalcification tank, so that the CO in the gas _2. While reacting with calcium and magnesium ions to form carbonate precipitation, hydrogen sulfide, mercaptans, ammonia, etc. in the biogas react with calcium and magnesium ions to purify the biogas, and the purified biogas can be collected in the gas storage tank in further use.

The electrolyzer described in step (4) and step (6) is equipped with a power supply and an electrolyzer; the electrode material in the electrolyzer is graphite, titanium, iron, aluminum, zinc, copper, lead, nickel, molybdenum, chromium, alloy and one of the nano-catalytic inert materials; the surface layer of the nano-catalytic inert electrode is coated with a metal oxide inert catalytic coating with a grain size of 10-35nm, and the substrate of the nano-catalytic inert electrode is a titanium plate or a plastic plate .

The membrane modules of the MBR system described in step (7) MBR treatment are selected from polyvinylidene fluoride hollow fiber membranes, polypropylene hollow fiber membranes, polysulfone hollow fiber membranes, polyethersulfone hollow fiber membranes, polyacrylonitrile hollow fiber membranes and One of polyvinyl chloride hollow fiber membranes; the membrane module of the MBR system has a membrane pore diameter of 0.10-0.2 μm, a working pressure of -1-50 kPa, and a working temperature of 5-45°C.

The effect of wastewater treatment above is shown in the table below:

Compared with the prior art, the present invention has the following outstanding advantages:

(1) After the false hardness (bicarbonate) is removed through the primary decalcification reaction of the chemical decalcification system, the carbonate radical reacts with calcium and magnesium ions to form carbonate precipitation through the secondary decalcification reaction pool, and then in In the coagulation tank, the carbonate precipitates and destabilizes, flocculates with coagulants such as FeSO ₄ and polyphenylene amide (PAM), and aggregates into coarse alum flower particles, which settle down in the primary sedimentation tank and finally effectively remove tobacco. The high-concentration calcium and magnesium ions in the wafer production wastewater have a removal rate of 50-90%, reduce the hardness of the water, make the Ca ²⁺ lower than 50 mg/L, prevent equipment scaling, and ensure the smooth subsequent biochemical treatment and electrolysis process. Stable operation.

(2) After being treated by the UASB anaerobic treatment system, the COD, BOD and other indicators in the wastewater are greatly reduced, and the generated gas is collected by the gas collection device and then introduced into the secondary decalcification reaction tank in the chemical decalcification, so that the CO in the gas _2React with calcium and magnesium ions to form carbonate precipitation. On the one hand, CO ₂ in the gas is recovered, so that the gas _can be used effectively; The gas storage tank is collected and utilized or discharged at high altitude.

(3) After treatment by the slag removal and chemical decalcification system, the removal rate of SS in the wastewater is over 95%, and the SS in the regulating tank is greatly reduced, avoiding the deposition of sludge in the regulating tank, and reducing the workload of sludge cleaning in normal operation.

(4) The strong oxidizing free radicals generated by nano-catalytic electrolysis make the difficult-to-biochemical macromolecular compounds in wastewater open rings and break chains, turning them into biochemical small molecules, further increasing the B/C value and improving the conditions for subsequent biochemical treatment. And remove the chroma and odor in the wastewater, reduce ammonia nitrogen, COD and other indicators.

(5) Through the A/O biochemical pool, through the alternating action of anaerobic and aerobic, the sewage can be denitrified and dephosphorized.

(6) After being treated by the MBR system, the pollutants in the water will be further decomposed through the oxidative decomposition of microorganisms. At the same time, the high-efficiency interception effect of the membrane is used to effectively remove SS, chroma, pollutants and other indicators, and the effluent water quality is stable and discharges up to the standard .

Description of drawings

Fig. 1 is a process flow diagram of the present invention.

Detailed ways

The present invention is the design of the wastewater treatment method for tobacco flake production after the in-depth and systematic comparative study of the components, properties and existing treatment schemes of the existing tobacco flake production wastewater. It uses chemical decalcification, biochemistry, electrolysis, MBR The combined use of methods such as these forms a treatment method especially suitable for tobacco sheet production wastewater.

The specific embodiment of the present invention is described below with reference to accompanying drawing 1.

Example 1

2000 tons/day tobacco sheet production wastewater treatment method.

The water quality indicators of the tobacco flake production wastewater are shown in Table 1 after determination.

Table 1 Water quality indicators of wastewater from tobacco flake production

serial number project unit measured value serial number project unit measured value 1 BOD ₅ mg/L 5800 5 Chroma times 15000 2 COD _Cr mg/L 25000 6 Ca ²⁺ mg/L 200 3 SS mg/L 15000 7 water temperature ℃ 50 4 pH value the 6.2 the the the the

(1) Slag removal

Wastewater from tobacco flake production is collected by pipelines and then discharged into mechanical coarse grid pool 1. Coarse grids are set in the pool to isolate and remove medium and coarse floating objects in the sewage to prevent subsequent processing equipment from clogging, and then through the lifting pump 22, Elevate the waste water from tobacco flake production to the rotary grill machine 2, further remove most of the insoluble suspended solids in the water through the filtration of the filter screen, pack the generated slag and transport it abroad, and the waste water passes through the air flotation tank 3, and the waste water is treated Large particle fibers and other suspended matter are separated, which greatly reduces the processing load of subsequent processes.

(2) Chemical decalcification

The effluent from the air flotation tank 3 flows into the first-level decalcification reaction tank 4 through the pipeline, and firstly adds an appropriate amount of lime saturated clear solution to adjust the pH value to 8.5 through the dosing device under stirring, and then flows into the second-level after removing the false hardness (bicarbonate) The decalcification reaction tank 5 is fed into the gas generated by the UASB anaerobic tank 10 in the anaerobic treatment of step (3), so that the CO ₂ in the gas reacts with calcium and magnesium ions to form carbonate precipitation, and the effluent flows into the coagulation tank under stirring conditions First add 6mg/L FeSO ₄ , then add Na ₂ CO ₃ to adjust the pH value to 8, and finally add 2mg/L polyphenylene amide (PAM), after the reaction is complete, enter the primary sedimentation tank 7 for precipitation and separation, so as to remove In addition to calcium and magnesium ions in tobacco treatment wastewater, the removal rate reaches 75%, reduces the hardness of water, and makes the Ca ²⁺ concentration 50 mg/L, preventing subsequent equipment and facilities from scaling due to excessive Ca ²⁺ ; primary sedimentation tank The sediment (that is, sludge) in 7 is sent to the sludge tank 20 through pumps and pipelines, and finally filtered and separated in the sludge filter press 21, and calcium carbonate is recovered, and the water from the primary sedimentation tank 7 enters the regulating tank 8 .

(3) Anaerobic treatment

The effluent from the adjustment tank 8 is lifted to the hydrolytic acidification tank 9 by the lifting pump 23, and stays in the hydrolytic acidification tank 9 for a certain period of time, and the macromolecular organic matter in the wastewater is hydrolyzed and acidified into small molecular organic acids by acid-producing bacteria under the action of the acid-producing bacteria. Then enter the UASB anaerobic pool 10 through the lifting pump 24, through the adsorption of anaerobic bacteria and facultative bacteria in the UASB anaerobic pool 10, fermentation, and under the joint action of methanogenesis, the organic acid will be decomposed into methane and carbon dioxide, and the anaerobic treatment will improve The B/C value of the wastewater improves the biodegradability of the wastewater; the generated methane and carbon dioxide are collected by the gas collection device 27 and then introduced into the secondary decalcification reaction tank 5 in the chemical decalcification step (2) to remove carbon dioxide, carbon dioxide, and Hydrogen sulfide and mercaptan compound impurities are purified and recycled to biogas in the biogas storage tank 28; waste water enters step (4).

(4) Electrolysis

The effluent from the UASB anaerobic tank 10 enters the electrolysis machine a11 for electrolysis to remove chromaticity and odor. At the same time, the difficult-to-biochemical macromolecular compounds in the wastewater are opened and broken into biochemical small molecules to further increase the B/C value. , to improve the conditions of the subsequent biochemical treatment; the voltage between two adjacent electrodes of the electrolysis machine a11 is 3V, and the current density is 300mA/cm ² .

(5) A/O processing

The effluent from the electrolysis enters the anoxic tank 12, the aerobic tank 13, and the intermediate sedimentation tank 14 in sequence, and part of the sludge in the intermediate sedimentation tank 14 flows back to the anoxic tank 12 through the reflux pump. Carry out nitrogen and phosphorus removal, and further oxidize and decompose the organic matter in the wastewater through aerobic treatment, and deeply remove COD and BOD; the aerobic pool 13 is evenly filled with a large number of biological suspension fillers to provide habitat, growth and reproduction places for aerobic microorganisms , so that microorganisms can form a biofilm on the surface of the filler. An aeration and oxygenation mixing system is installed at the bottom of the aerobic pool 13 to oxygenate the sewage to maintain the dissolved oxygen in the water at 2-4 mg/L. More adequate contact, in addition, through the agitation of gas and water backwashing, it can effectively wash away the aging biofilm growing on the surface of the filler, promote the replacement of the biofilm, and maintain a high activity of the biofilm.

(6) Secondary electrolysis

The effluent from the middle sedimentation tank 14 enters the electrolysis machine b15 again for electrolysis, so that the macromolecular organic matter that is difficult to biochemically undergoes electrolysis to undergo ring-opening and chain breaking, and is converted into small molecular organic matter that is easy to biochemically, increasing the B/C; during electrolysis, two adjacent The voltage between the electrodes was 6V, and the current density was 20mA/cm ² .

(7) MBR processing

The effluent from the secondary electrolysis enters the MBR system 16, which performs biochemical and membrane separation on the wastewater, degrades the remaining organic pollutants and removes suspended solids.

(8) Disinfection

After the wastewater is treated by MBR, the effluent is lifted by the lifting pump 25 to the electrolytic disinfection tank 17 for treatment, which can further remove chroma, and sterilize the wastewater, and finally discharge it through the discharge channel 18 up to the standard.

(9) Sludge treatment

The UASB anaerobic tank 10 in step (3) anaerobic treatment, the anoxic tank 12, aerobic tank 13 and middle sedimentation tank 14 in step (5) A/O treatment, and the sludge generated in step (7) MBR treatment are all passed through The pipeline enters the sludge tank 20, and then the sludge is dehydrated by the sludge filter press 21 to reduce the volume of the sludge. After dehydration, the mud cake is incinerated, and the filtrate is returned to the regulating tank 8 in step (2) chemical decalcification.

The quality indicators of the effluent water were determined and shown in Table 2.

Table 2 Water quality indicators of effluent

serial number project unit measured value serial number project unit measured value 1 BOD ₅ mg/L 20 5 Chroma times 20 2 COD _Cr mg/L 60 6 Ca ²⁺ mg/L 40 3 SS mg/L 60 7 water temperature ℃ twenty three 4 pH value the 6.8 the the the the

Example 2

The treatment method of 5000 tons/day tobacco flake production wastewater.

The water quality indicators of the tobacco sheet production wastewater were determined and shown in Table 3.

Table 3 Water quality indicators of tobacco sheet production wastewater

serial number project unit measured value serial number project unit measured value 1 BOD ₅ mg/L 2000 5 Chroma times 25000 2 COD _Cr mg/L 8000 6 Ca ²⁺ mg/L 300 3 SS mg/L 6200 7 water temperature ℃ 55 4 pH value the 6 the the the the

(1) Slag removal

Wastewater from tobacco flake production is collected by pipelines and then discharged into mechanical coarse grid pool 1. Coarse grids are set in the pool to isolate and remove medium and coarse floating objects in the sewage to prevent subsequent processing equipment from clogging, and then through the lifting pump 22, Elevate the waste water from tobacco flake production to the rotary grill machine 2, further remove most of the insoluble suspended solids in the water through the filtration of the filter screen, pack the generated slag and transport it abroad, and the waste water passes through the air flotation tank 3, and the waste water is treated Large particle fibers and other suspended matter are separated, which greatly reduces the processing load of subsequent processes.

(2) Chemical decalcification

The effluent from the air flotation tank 3 flows into the first-level decalcification reaction tank 4 through the pipeline, and firstly adds an appropriate amount of lime saturated clarified solution to adjust the pH value to 9.5 through the dosing device under stirring. After removing the false hardness (bicarbonate), it flows into the second-level Decalcification reaction tank 5, add 400mg/L Na ₂ CO ₃ , make carbonate radical react with calcium and magnesium ions to form carbonate precipitate, make CO ₂ in the gas react with calcium and magnesium ion to form carbonate precipitate, and the effluent flows into coagulation After the pool, add 10mg/L FeSO ₄ under stirring conditions, then add Na ₂ CO ₃ to reverse the pH value to 8.5, and finally add 2.5mg/L polyphenylene amide (PAM), and enter the primary sedimentation tank after the reaction is complete 7 Precipitation and separation are carried out to remove calcium and magnesium ions in tobacco treatment wastewater, with a removal rate of 84%, reducing the hardness of water, making the Ca ²⁺ concentration 48 mg/L, and preventing subsequent equipment and facilities from being caused by excessive Ca ²⁺ formation. Scale; the sediment (i.e. sludge) in the primary sedimentation tank 7 is sent into the sludge tank 20 through pumps and pipelines, and finally filtered and separated in the sludge dehydration device, and calcium carbonate is recovered, and the water out of the primary sedimentation tank 7 enters Conditioning pool8.

(3) Anaerobic treatment

The effluent from the adjustment tank 8 is lifted to the hydrolytic acidification tank 9 by the lifting pump 23, and stays in the hydrolytic acidification tank 9 for a certain period of time, and the macromolecular organic matter in the wastewater is hydrolyzed and acidified into small molecular organic acids by acid-producing bacteria under the action of the acid-producing bacteria. Then enter the UASB anaerobic pool 10 through the lifting pump 24, through the adsorption of anaerobic bacteria and facultative bacteria in the UASB anaerobic pool 10, fermentation, and under the joint action of methanogenesis, the organic acid will be decomposed into methane and carbon dioxide, and the anaerobic treatment will improve The B/C value of the wastewater improves the biodegradability of the wastewater; the generated methane and carbon dioxide are collected by the gas collection device 27 and then introduced into the secondary decalcification reaction tank 5 in the chemical decalcification step (2) to remove carbon dioxide, carbon dioxide, and Hydrogen sulfide and mercaptan compound impurities are purified and recycled to biogas in the biogas storage tank 28; waste water enters step (4).

(4) Electrolysis

The effluent from the UASB anaerobic tank 10 enters the electrolysis machine a11 for electrolysis to remove chromaticity and odor. At the same time, the difficult-to-biochemical macromolecular compounds in the wastewater are opened and broken into biochemical small molecules to further increase the B/C value. , to improve the conditions of the subsequent biochemical treatment; the voltage between two adjacent electrodes of the electrolysis machine a11 is 8V, and the current density is 150mA/cm ² .

(5) A/O processing

The effluent from the electrolysis enters the anoxic tank 12, the aerobic tank 13, and the intermediate sedimentation tank 14 in sequence, and part of the sludge in the intermediate sedimentation tank 14 flows back to the anoxic tank 12 through the reflux pump. Carry out nitrogen and phosphorus removal, and further oxidize and decompose the organic matter in the wastewater through aerobic treatment, and deeply remove COD and BOD; the aerobic pool 13 is evenly filled with a large number of biological suspension fillers to provide habitat, growth and reproduction places for aerobic microorganisms , so that microorganisms can form a biofilm on the surface of the filler. An aeration and oxygenation mixing system is installed at the bottom of the aerobic pool 13 to oxygenate the sewage to maintain the dissolved oxygen in the water at 2-4 mg/L. More adequate contact, in addition, through the agitation of gas and water backwashing, it can effectively wash away the aging biofilm growing on the surface of the filler, promote the replacement of the biofilm, and maintain a high activity of the biofilm.

(6) Secondary electrolysis

The effluent from the middle sedimentation tank 14 enters the electrolysis machine b15 again for electrolysis, so that the macromolecular organic matter that is difficult to biochemically undergoes electrolysis to undergo ring-opening and chain breaking, and is converted into small molecular organic matter that is easy to biochemically, increasing the B/C; during electrolysis, two adjacent The voltage between the electrodes was 4 V, and the current density was 100 mA/cm ² .

(7) MBR processing

The effluent from the secondary electrolysis enters the MBR system 16, which performs biochemical and membrane separation on the wastewater, degrades the remaining organic pollutants and removes suspended solids.

(8) Disinfection

After the wastewater is treated by MBR, the effluent is lifted by the lifting pump 25 to the electrolytic disinfection tank 17 for treatment, which can further remove chroma, and sterilize the wastewater, and finally discharge it through the discharge channel 18 up to the standard.

(9) Sludge treatment

The UASB anaerobic tank 10 in step (3) anaerobic treatment, the anoxic tank 12, aerobic tank 13 and middle sedimentation tank 14 in step (5) A/O treatment, and the sludge generated in step (7) MBR treatment are all passed through The pipeline enters the sludge tank 20, and then the sludge is dehydrated by the sludge filter press 21 to reduce the volume of the sludge. After dehydration, the mud cake is incinerated, and the filtrate is returned to the regulating tank 8 in step (2) chemical decalcification.

The quality indicators of the effluent water were determined and shown in Table 4.

Table 4 Water quality indicators of treated effluent

serial number project unit measured value serial number project unit measured value 1 BOD ₅ mg/L 15 5 Chroma times 20 2 COD _Cr mg/L 60 6 Ca ²⁺ mg/L 35 3 SS mg/L 40 7 water temperature ℃ 25 4 pH value the 6.5 the the the the

Example 3

8000 tons/day tobacco sheet production waste water recycling method.

The water quality indicators of the tobacco sheet production wastewater were determined and shown in Table 5.

Table 5 Water quality indicators of tobacco sheet production wastewater

serial number project unit measured value serial number project unit measured value 1 BOD ₅ mg/L 600 5 Chroma times 20000 2 COD _Cr mg/L 2000 6 Ca ²⁺ mg/L 400 3 SS mg/L 1000 7 water temperature ℃ 50 4 pH value the 6.5 the the the the

(1) Slag removal

Wastewater from tobacco flake production is collected by pipelines and then discharged into mechanical coarse grid pool 1. Coarse grids are set in the pool to isolate and remove medium and coarse floating objects in the sewage to prevent subsequent processing equipment from clogging, and then through the lifting pump 22, Elevate the waste water from tobacco flake production to the rotary grill machine 2, further remove most of the insoluble suspended solids in the water through the filtration of the filter screen, pack the generated slag and transport it abroad, and the waste water passes through the air flotation tank 3, and the waste water is treated Large particle fibers and other suspended matter are separated, which greatly reduces the processing load of subsequent processes.

(2) Chemical decalcification

The effluent from the air flotation tank 3 flows into the first-level decalcification reaction tank 4 through the pipeline, and first adds an appropriate amount of lime saturated clear solution to adjust the pH value to 9.0 through the dosing device under stirring. After removing the false hardness (bicarbonate), it flows into the second-level Decalcification reaction tank 5, add 100mg/L Na ₂ CO ₃ , make carbonate radical react with calcium and magnesium ions to form carbonate precipitate, make CO ₂ in the gas react with calcium and magnesium ion to form carbonate precipitate, and the effluent flows into coagulation After the pool, add 5mg/L FeSO ₄ under stirring conditions, then add Na ₂ CO ₃ to adjust the pH value to 9.0, and finally add 3mg/L polyphenylene amide (PAM), and enter the primary sedimentation tank 7 after the reaction is complete. Precipitation and separation, so as to remove calcium and magnesium ions in tobacco treatment wastewater, the removal rate reaches 87.5%, reduces the hardness of water, makes the Ca ²⁺ concentration 50mg/L, and prevents subsequent equipment and facilities from scaling due to excessive Ca ²⁺ The sediment (i.e. sludge) in the primary sedimentation tank 7 is sent into the sludge tank 20 through pumps and pipelines, and finally filtered and separated in the sludge dehydration device, and calcium carbonate is recovered, and the water outlet from the primary sedimentation tank 7 enters the regulation Pool 8.

(3) Anaerobic treatment

The effluent from the adjustment tank 8 is lifted to the hydrolytic acidification tank 9 by the lifting pump 23, and stays in the hydrolytic acidification tank 9 for a certain period of time, and the macromolecular organic matter in the wastewater is hydrolyzed and acidified into small molecular organic acids by acid-producing bacteria under the action of the acid-producing bacteria. Then enter the UASB anaerobic pool 10 through the lifting pump 24, through the adsorption of anaerobic bacteria and facultative bacteria in the UASB anaerobic pool 10, fermentation, and under the joint action of methanogenesis, the organic acid will be decomposed into methane and carbon dioxide, and the anaerobic treatment will improve The B/C value of the wastewater improves the biodegradability of the wastewater; the generated methane and carbon dioxide are collected by the gas collection device 27 and then introduced into the secondary decalcification reaction tank 5 in the chemical decalcification step (2) to remove carbon dioxide, carbon dioxide, and Hydrogen sulfide and mercaptan compound impurities are purified and recycled to biogas in the biogas storage tank 28; waste water enters step (4).

(4) Electrolysis

The effluent from the UASB anaerobic tank 10 enters the electrolysis machine a11 for electrolysis to remove chromaticity and odor. At the same time, the difficult-to-biochemical macromolecular compounds in the wastewater are opened and broken into biochemical small molecules to further increase the B/C value. , to improve the conditions of the subsequent biochemical treatment; the voltage between two adjacent electrodes of the electrolysis machine a11 is 12V, and the current density is 50mA/cm ² .

(5) A/O processing

The effluent from the electrolysis enters the anoxic tank 12, the aerobic tank 13, and the intermediate sedimentation tank 14 in sequence, and part of the sludge in the intermediate sedimentation tank 14 flows back to the anoxic tank 12 through the reflux pump. Carry out nitrogen and phosphorus removal, and further oxidize and decompose the organic matter in the wastewater through aerobic treatment, and deeply remove COD and BOD; the aerobic pool 13 is evenly filled with a large number of biological suspension fillers to provide habitat, growth and reproduction places for aerobic microorganisms , so that microorganisms can form a biofilm on the surface of the filler. An aeration and oxygenation mixing system is installed at the bottom of the aerobic pool 13 to oxygenate the sewage to maintain the dissolved oxygen in the water at 2-4 mg/L. More adequate contact, in addition, through the agitation of gas and water backwashing, it can effectively wash away the aging biofilm growing on the surface of the filler, promote the replacement of the biofilm, and maintain a high activity of the biofilm.

(6) Secondary electrolysis

The effluent from the middle sedimentation tank 14 enters the electrolysis machine b15 again for electrolysis, so that the macromolecular organic matter that is difficult to biochemically undergoes electrolysis to undergo ring-opening and chain breaking, and is converted into small molecular organic matter that is easy to biochemically, increasing the B/C; during electrolysis, two adjacent The voltage between the electrodes was 2 V, and the current density was 200 mA/cm ² .

(7) MBR processing

The effluent from the secondary electrolysis enters the MBR system 16, which performs biochemical and membrane separation on the wastewater, degrades the remaining organic pollutants and removes suspended solids.

(8) Disinfection

After the wastewater is treated by MBR, the effluent is lifted by the lifting pump 25 to the electrolytic disinfection tank 17 for treatment, which can further remove chroma, and sterilize the wastewater, and finally discharge it up to the standard.

(9) Sludge treatment

The UASB anaerobic tank 10 in step (3) anaerobic treatment, the anoxic tank 12, aerobic tank 13 and middle sedimentation tank 14 in step (5) A/O treatment, and the sludge generated in step (7) MBR treatment are all passed through The pipeline enters the sludge tank 20, and then the sludge is dehydrated by the sludge filter press 21 to reduce the volume of the sludge. After dehydration, the mud cake is incinerated, and the filtrate is returned to the regulating tank 8 in step (2) chemical decalcification.

The water quality indicators of the effluent were determined and are shown in Table 6.

Table 6 Water quality indicators of effluent

serial number project unit measured value serial number project unit measured value 1 BOD ₅ mg/L 15 5 Chroma times 20 2 COD _Cr mg/L 60 6 Ca ²⁺ mg/L 40 3 SS mg/L 50 7 water temperature ℃ 25 4 pH value the 6 the the the the

Claims (6)

1. a treatment process for tobacco sheet factory effluent, it comprises the following steps:

(1) slagging-off

Tobacco sheet factory effluent enters mechanical coarse rack water collecting basin after pipeline is collected, coarse rack is set in pond, thick cursory thing in sewage is isolated to removal, then pass through lift pump, tobacco sheet factory effluent water extraction is risen in rotating machinery grid maker, by the filtration of filter screen, further removes the suspended substance of most of insolubility in water, generation every slag packing outward transport, waste water carries out air supporting through air flotation pool, and macrobead fiber in waste water and other suspended substances are carried out to separation;

(2) chemical decalcification

Air flotation pool water outlet flows into one-level decalcification reaction tank through pipeline, through chemicals dosing plant, under agitation first add the saturated settled solution of appropriate lime adjust pH to 8.5～9.5, remove after supercarbonate, flow into secondary decalcification reaction tank, pass into the gas that in step (3) anaerobic treatment, UASB anaerobic pond produces, make CO in gas ₂react with calcium ions and magnesium ions and generate carbonate deposition, or add the Na of 100 ~ 400mg/L ₂cO ₃carbonate is reacted with calcium ions and magnesium ions and generate carbonate deposition, water outlet first adds the FeSO of 5 ~ 10mg/L after flowing into coagulation basin under agitation condition ₄, then add Na ₂cO ₃anti-adjust pH to 8～9, the polyacrylamide (PAM) that finally adds 2 ~ 3mg/L, after reacting completely, enter preliminary sedimentation tank and carry out precipitate and separate, throw out in preliminary sedimentation tank is sent in sludge sump through pump and pipeline, finally in sludge dehydration device, carry out filtering separation, and reclaim calcium carbonate, preliminary sedimentation tank water outlet enters equalizing tank;

(3) anaerobic treatment

Equalizing tank water outlet is promoted to hydrolysis acidification pool through lift pump, at hydrolysis acidification pool, stop certain hour, utilize acid-producing bacteria that the acidication under the effect of acid-producing bacteria of the larger molecular organics in waste water is become to small molecular organic acid, then through lift pump, enter UASB anaerobic pond, through anerobe in UASB anaerobic pond, the absorption of double oxygen bacterium, fermentation, produce under methane acting in conjunction organic acid is resolved into methane and carbon dioxide, the methane and carbon dioxide producing imports the secondary decalcification reaction tank in the chemical decalcification of step (2) after gas collector is collected, after purifying, secondary decalcification reaction tank reclaims biogas in gas holder, waste water enters step (4),

(4) electrolysis

The water outlet of UASB anaerobic pond enters electrolysis machine a and carries out electrolysis, and the adjacent two interelectrode voltages of electrolysis machine a are 2～12V, and current density is 10～320mA/cm ²;

(5) A/O processes

Electrolysis water outlet enters anoxic pond, Aerobic Pond and medium sediment pool successively, and the part mud of medium sediment pool is back to anoxic pond by reflux pump, utilize under the alternating action of anoxic, aerobic microbiological and can carry out denitrogenation dephosphorizing, and by the organism in the further oxygenolysis waste water of aerobic treatment, the degree of depth is removed COD and BOD, in Aerobic Pond, evenly fill up a large amount of biological suspended packings, for providing, aerobic microbiological perches, the place of growth and breeding, so that microorganism forms microbial film at filling surface, in Aerobic Pond bottom, be provided with aeration aerating stirring system, sewage is carried out to oxygenation, make the dissolved oxygen in water maintain 2～4 mg/L, the effect that simultaneously utilizes gas to rise, suspended substance in pond is more fully contacted with water, in addition by the agitaion of gas and clear water back flushing, can effectively to the aging microbial film of filling surface growth, wash away, impel biomembranous update, make microbial film maintain higher activity,

(6) re-electrolysis

Medium sediment pool water outlet again enters electrolysis machine b and carries out electrolysis, and during electrolysis machine b, adjacent two interelectrode voltages are 2～6V, and current density is 20～200mA/cm ²;

(7) MBR processes

The water outlet of re-electrolysis enters MBR system, and waste water is carried out to biochemistry, membrane sepn effect, degraded residue organic pollution materials and removal suspended substance;

(8) sterilization

Waste water is after MBR processes, and water outlet is processed through electrosterilization pond again, can further remove colourity, and waste water is carried out to sterilization and disinfection, last qualified discharge;

(9) sludge treatment

During UASB anaerobic pond in step (3) anaerobic treatment, step (5) A/O process, anoxic pond, Aerobic Pond and medium sediment pool and step (7) MBR process the mud producing and by pipeline, enter sludge sump, then the dehydration through sludge filter press makes reducing sludge volume, after dehydration, mud cake carries out burning disposal, and filtrate is back to the equalizing tank in the chemical decalcification of step (2).

2. the treatment process of a kind of tobacco sheet factory effluent according to claim 1, is characterized in that: described in step (1) slagging-off, air supporting is a kind of of gas distribution By Bubble-floating Method, electric floating method, biology and chemical floatation treatment, dissolved air flotation.

3. the treatment process of a kind of tobacco sheet factory effluent as claimed in claim 1, is characterized in that: step (4) and the described electrolysis machine of step (6) are provided with power supply and electrolyzer; Electrode materials in described electrolyzer is a kind of in graphite, titanium, iron, aluminium, zinc, copper, lead, nickel, molybdenum, chromium, alloy and nano-catalytic inert material.

4. the treatment process of a kind of tobacco sheet factory effluent as claimed in claim 3, it is characterized in that: the top layer of described nano-catalytic noble electrode is coated with the metal oxide inertia catalyst coatings that crystal grain is 10～35nm, and the substrate of described nano-catalytic noble electrode is titanium plate or plastic plate.

5. the treatment process of a kind of tobacco sheet factory effluent according to claim 1, is characterized in that: the membrane module of MBR system described in step (7) MBR processes is selected from a kind of in Pvdf Microporous Hollow Fiber Membrane, polypropylene hollow fiber membrane, ps hollow fiber uf membrane, polyether sulphone hollow fibre film, polyacrylonitrile hollow fiber membrane and PVC hollow fiber membrane.

6. a kind for the treatment of process of tobacco sheet factory effluent according to claim 1 or 5, is characterized in that: the membrane pore size of the membrane module of described MBR system is 0.10～0.2 μ m, and operating pressure is-1～-50kPa, and working temperature is 5～45 ℃.