CN118026473A

CN118026473A - Sewage zero discharge treatment method and device for filter production line

Info

Publication number: CN118026473A
Application number: CN202410370242.3A
Authority: CN
Inventors: 林彬鹏; 温在涛; 黄国梁; 蔡战林
Original assignee: Zhejiang Huansen Environmental Technology Co ltd
Current assignee: Zhejiang Huansen Environmental Technology Co ltd
Priority date: 2024-03-29
Filing date: 2024-03-29
Publication date: 2024-05-14

Abstract

The invention discloses a sewage zero-emission treatment method and device for a filter production line, and belongs to the field of wastewater treatment. The processing method comprises the following steps: s1, oil removal treatment; s2, coagulation air floatation; s3, softening and coagulating; s4, performing ozone oxidation; s5, adsorbing and filtering; s6, nanofiltration, wherein the sewage of the filter production line comprises 0.21-1.11 mg/L of iron, 0.05-0.24 mg/L of zinc and less than 0.05mg/L of nickel. The sewage zero-emission treatment method for the filter production line provided by the invention has no biochemical treatment step, avoids the influence of heavy metals on biochemical treatment, is simple in operation and stable in daily operation, and can meet the requirement of urban sewage recycling industrial water quality.

Description

Sewage zero discharge treatment method and device for filter production line

Technical Field

The invention belongs to the field of wastewater treatment, and particularly relates to a zero-discharge sewage treatment method and device for a filter production line.

Background

The comprehensive sewage generated during the production of the filter belongs to the oil-containing sewage of mechanical processing, and the main pollutants are CODcr, SS and the like. The Chemical Oxygen Demand (COD) concentration of the inlet water is 80-151 mg/L, the Biological Oxygen Demand (BOD) concentration is 30-40 mg/L, the ammonia nitrogen (NH ₃ -N) concentration is 0.043-1.10 mg/L, the Total Phosphorus (TP) concentration is 0.18-0.29 mg/L, the iron (Fe) concentration is 0.21-1.11 mg/L, the zinc (Zn) concentration is 0.05-0.24 mg/L, the nickel (Ni) concentration is less than 0.05mg/L, pH and is between 8.80-10.16, and the alkali and suspended matter (SS) concentration is 34-51 mg/L.

The prior sewage zero discharge treatment technology of the filter production line is generally an oil separation tank, a flocculation sedimentation tank, a biochemical tank and a secondary sedimentation tank. The oil in the sewage is required to be removed, the dosage required by the flocculation sedimentation tank is large, and the operation cost is high. Meanwhile, the sewage is discharged in places to implement the process and product water standard in the urban sewage recycling Industrial Water quality (GB/T19923-2005).

Through retrieval, CN113603302A discloses a coking wastewater reduction treatment method. The coking wastewater is treated by the processes of an adjusting tank, air flotation degreasing, coagulating sedimentation, a biochemical homogenizing tank, a biological filter tank, a secondary sedimentation tank, a UV advanced ozone oxidation tank, ultrafiltration, reverse osmosis, a chemical softening tank, sand filtration, resin, an adjusting tank, ultrafiltration, nanofiltration and bipolar membrane electrodialysis, and the generated acid and alkali can be used for the process recycling such as pH adjustment in the treatment process. Is not suitable for the sewage of the filter production line containing heavy metals and mineral oil.

Patent CN114906975A discloses a zero-emission treatment process of coking wastewater, which comprises biochemical treatment, advanced treatment and salt separation crystallization, wherein the advanced treatment comprises wastewater pretreatment, reverse osmosis concentration and sludge dehydration. The pretreatment of the wastewater comprises pretreatment dosing, efficient clarification, multi-medium filtration, ultrafiltration, resin softening, carbon dioxide removal and organic matter removal, wherein the organic matter removal comprises adsorption in an adsorption tank, desorption outside the adsorption tank and wet oxidation of elution waste liquid.

Patent CN107253798A relates to a combined process for advanced treatment and reuse of wastewater in the iron and steel industry. After being treated by a cooling unit and an immersed ultrafiltration unit, the iron and steel industrial wastewater firstly enters a reverse osmosis unit for primary desalination, the desalted reverse osmosis produced water is sent to a water supply system for graded reuse, and the concentrated water generated by the reverse osmosis unit sequentially passes through a softening clarification tank, an ozone oxidation tank, a nitrification denitrification biological filter, a multi-medium filter, an external pressure ultrafiltration unit and the like for secondary desalination, and then enters a nanofiltration unit for secondary desalination, the desalted nanofiltration produced water is sent to the water supply system for graded reuse, and the concentrated water generated by the nanofiltration unit sequentially passes through a Fenton oxidation tank, an ozone oxidation tank, an activated carbon biological filter and a break point chlorination tank for treatment and then is discharged after reaching standards. However, the steel wastewater does not contain oil, and the influence of the oil on wastewater treatment is not required to be considered.

Patent CN101935118a discloses a hot water membrane purification and reuse process, which can work at high temperature by a combination process of ultra-micro filtration membrane system, reverse osmosis, nanofiltration membrane system, pretreatment, activated carbon adsorption, ion exchange and the like, can purify various hot water and waste water, has double effects of recovering water resources and heat energy, and can adopt different process combinations and flows according to the components of water quality, and does not contain oil components such as mineral oil.

However, biochemical treatment is adopted in the treatment method, and for the wastewater of the filter production line with high heavy metal content, the heavy metal has poisoning effect on microorganisms in the biochemical treatment step, so that the treatment effect is affected.

Disclosure of Invention

1. Problems to be solved

Aiming at the problem that the existing biochemical treatment method is difficult to treat the wastewater of the filter production line with high heavy metal content, the invention provides a zero-emission treatment method and device for the wastewater of the filter production line, and the method and device are used for treating the wastewater of the filter production line, so that the daily operation is stable, and the effluent water can meet the requirement of urban wastewater recycling industrial water quality.

2. Technical proposal

In order to solve the problems, the technical scheme adopted by the invention is as follows:

a sewage zero-emission treatment method for a filter production line comprises the following steps:

S1, oil removal treatment: the wastewater is subjected to oil removal treatment by flowing into an oil removal adjusting tank.

Wherein, the oil separation treatment utilizes the difference of specific gravity of suspended matters and water in the wastewater to achieve the purpose of separation. After the oily wastewater enters the oil separation regulating tank, the oily wastewater slowly flows along the horizontal direction, and flows through the multi-lattice oil separation regulating tank, so that the oil floats on the water surface in the flowing process, and the water passing holes are arranged below the water surface, so that the oil and other impurities on the water surface can be conveniently trapped. The separated sewage enters the last grid through the water passing holes and is lifted to the floatation tank through the oil separation adjusting tank lifting pump.

S2, coagulation air floatation: pumping the effluent of the oil separation regulating tank to an air floatation tank, adding a neutralizing agent, a flocculating agent and a coagulant aid, and floating the oil substances, suspended matters, COD and other pollutants in the wastewater to the water surface under the action of dissolved air water to be removed by a slag scraping system.

Wherein the neutralizing agent comprises one or more of caustic soda flakes, lime and sodium carbonate, and is used for adjusting the wastewater to a proper pH range, preferably pH is 7-8, so that the wastewater is easy to coagulate; the flocculant comprises one or more of PAC, aluminum sulfate and ferrous chloride, and is used for gathering suspended substances and colloid substances in water; the coagulant aid comprises one or more of PAM, PCE and biological glue.

S3, softening and coagulating: the clarified effluent of the floatation tank flows into a softening coagulation tank, and under the action of a softener, a flocculant and a coagulant aid, pollutants such as COD, suspended matters, heavy metals and the like in the wastewater are further precipitated and removed, so that the hardness of the water is reduced, the metal ions in the concentrated solution subjected to membrane filtration at last are reduced, and the amount of the concentrated solution is reduced. Sludge generated in coagulation air floatation and softening coagulation is filtered and dried by a plate-and-frame filter press.

Wherein, the softener comprises one or more of sodium carbonate, quicklime and slaked lime, and is used for removing hardness in water, namely 2-valence metal ion calcium, magnesium and the like; the flocculant comprises one or more of PAC, aluminum sulfate and ferrous chloride, and aggregates the precipitate formed by the 2-valence metal ions; the coagulant aid comprises one or more of PAM, PCE and biological glue, and is used for connecting aggregated substances, so that flocculent volume is increased and precipitation is facilitated.

S4, ozone oxidation: supernatant water obtained from the sedimentation tank flows into an ozone catalytic oxidation tank, and ozone generated by an ozone generator is used for carrying out strong oxidation removal on refractory substances in the wastewater, so that the COD content is further reduced. Wherein, an ozone generator is arranged in the ozone catalytic oxidation pond.

S5, adsorbing and filtering: the effluent of the ozone catalytic oxidation pond is pumped to a multi-medium filter through a water inlet pump to adsorb and filter micro suspended matters, so that the stable operation of a post-treatment system is ensured.

The medium in the multi-medium filter comprises quartz sand, anthracite, active carbon, magnetite, garnet, porous ceramic, plastic balls and the like, and in the screening process of the multi-medium filter, larger particles and suspended matters are intercepted in the deep part of a filter material when the material layer is filtered by water flow, and smaller particles and dissolved matters can pass through the filter material layer. In the adsorption process, the micro pore canal of the adsorption filter material such as activated carbon can adsorb organic substances, chlorine, peculiar smell and other harmful substances in water, so that the water quality is better purified.

S6, nanofiltration: the effluent of the multi-medium filter enters an SNF membrane system to remove pollutants such as COD, ammonia nitrogen, divalent salt and the like in the wastewater, and the produced water of the SNF membrane system can reach the standard for recycling after entering a water producing tank. The removal rates of COD, ammonia nitrogen and total phosphorus of the sewage in the SNF membrane system are respectively 60% -70%, 55% -60% and 98% -99%. The concentrated water obtained by SNF membrane component treatment is cooled by a low-temperature evaporation concentrator, salt is separated out at 160-200 ℃, most 2-valent and 3-valent salts are removed, and a small amount of monovalent salts are removed.

The utility model provides a filter production line sewage zero release processing apparatus, includes deoiling unit, reaction unit, filtration unit, produces water unit, dosing unit, sludge treatment unit and dense water treatment unit, except that material unit, reaction unit, filtration unit and produce water unit and connect gradually, dosing unit is connected with reaction unit and filtration unit respectively, sludge treatment unit is connected with reaction unit and filtration unit respectively, dense water treatment unit is connected with the filtration unit rear end.

The oil removal unit comprises an oil removal regulating tank, and the oil removal regulating tank is provided with a lifting pump for inputting sewage into the reaction unit.

Still further, the oil removal equalizing basin is the many check oil removal equalizing basins that the plane is the rectangle, and it is equipped with a plurality of cell body, oil removal equalizing basin lateral wall is equipped with the water hole, and sewage flows between adjacent oil removal equalizing basin through the water hole.

The reaction unit comprises an air floatation tank, a softening coagulation tank and an ozone catalytic oxidation tank which are connected in sequence.

The air floatation tank comprises a tank body and an air dissolving device, the air dissolving device comprises an air dissolving tank and an air floatation air dissolving pump connected with the air dissolving tank, and the air dissolving tank is used for introducing air into the position below the liquid surface of the tank body through the air floatation air dissolving pump. Still be equipped with in the air supporting pond and scrape the sediment device, it includes at least one and scrape the sediment board to scrape the sediment device, it is located the air supporting pond liquid level to scrape the sediment board, through drive arrangement operation, the air supporting pond below is equipped with the mud pond, through the continuous operation of scraping the sediment board, will float on the impurity on surface constantly and scrape to in the mud pond. The treated sewage overflows from the pipeline to the softening coagulation tank.

The softening coagulation tank comprises a reaction tank and a sedimentation tank, wherein the reaction tank and the sedimentation tank are isolated by a baffle, a water passing hole is formed in the baffle, wastewater flows between the reaction tank and the sedimentation tank through the water passing hole, the sedimentation tank is used for carrying out gravity sedimentation on flocculent sediment generated by the reaction tank, and the lower part of the sedimentation tank is connected with the sludge tank through a pipeline. The reaction tank is internally provided with a first stirring device for uniformly mixing the wastewater with the reaction reagent.

Furthermore, the sedimentation tank is internally provided with inclined pipes which are parallel to each other, the inclined pipes are preferably made of PP materials, and the inclined pipes are utilized to partition the wastewater and the reaction reagent in the sedimentation tank, so that sedimentation accumulation and enrichment are reduced, and sedimentation efficiency is affected.

The ozone catalytic oxidation pond is isolated from the sedimentation pond through a baffle, an overflow weir is arranged on the upper portion of the baffle, an ozone generator is arranged in the ozone catalytic oxidation pond and used for oxidizing and removing organic matters, and finally the treated sewage enters a filtering unit for filtering.

Still further, still include the internal circulation pump, circulate through the internal circulation pump, let ozone and sewage fully react.

The filtering unit comprises a multi-medium filter and an SNF membrane device which are sequentially connected.

The SNF membrane device comprises a precision filter and an SNF membrane assembly, and is used for removing pollutants such as COD, ammonia nitrogen, divalent salt and the like in the wastewater, and the produced water of the SNF membrane system can reach the standard and be recycled after entering a produced water tank. The SNF membrane module comprises a precise filter, wherein an SNF booster pump is arranged in front of the precise filter and used for boosting water entering the precise filter, and an SNF high-pressure pump is arranged in front of the SNF membrane module and used for boosting water entering the SNF membrane module.

Still further, be equipped with former cask between multi-media multi-filter and the SNF membrane device.

The SNF membrane device is connected with a water production tank, and produced water meeting the standard of recycled water is recycled in the production process through a recycling water pump.

The dosing unit comprises at least one dosing tank and is used for feeding materials into the air floatation tank, the softening coagulation tank and the filtering unit, and a valve is arranged on a dosing pipeline of the dosing tank and is used for controlling dosing flow.

The sludge treatment unit comprises a plate-and-frame filter press, the plate-and-frame filter press is connected with the sludge tank and is used for receiving sludge scraped by the slag scraping device of the air floatation tank and sludge precipitated to the bottom in the sedimentation tank, and the plate-and-frame filter press is used for filtering the sludge and processing the filtered sludge outside the sludge commission.

Furthermore, in the plate and frame filter pressing process, the pneumatic diaphragm pump is driven by the air compressor to realize rapid filter pressing of sludge.

The concentrated water treatment unit comprises a concentrated water bucket, the concentrated water bucket is connected with the SNF membrane assembly and receives concentrated water treated by the SNF membrane assembly, one end of the concentrated water bucket is connected with the air floatation tank, and a part of concentrated water in the concentrated water bucket is introduced into the air floatation tank and is reprocessed by the reaction unit and the filtering unit. The other end of the concentrated water bucket is connected with a concentrated water circulating bucket, the concentrated water circulating bucket is sequentially connected with a low-temperature evaporation concentrator and a cooling tower, the concentrated water is cooled by the low-temperature evaporation concentrator, salt is separated out at low temperature of the concentrated water, and the temperature is controlled to be 160-200 ℃.

Wherein, agitating unit is equipped with in air supporting pond, the reaction tank for the misce bene of reactant.

The air floatation tank is provided with an online pH meter, and the pH value of the wastewater in the reaction unit is controlled to be 7-8.

According to the zero-emission treatment method for sewage in the filter production line, the oxidizing property (oxidation potential 2.03V) of ozone is utilized to directly oxidize organic matters in water or oxidize and decompose macromolecular organic matters into small molecules, so that the small molecules are easier to degrade. The ozone catalytic oxidation technology is particularly suitable for wastewater treatment with poor biodegradability. The ozone oxidation technology has simple flow, short treatment time, no residue and no secondary pollution.

The application adopts oil removal treatment, coagulation air flotation, softening coagulation, ozone oxidation, filtration, adsorption and nanofiltration. Notably, the method of the present application is particularly applicable to oily wastewater containing zinc, iron, nickel. Firstly, oil removal treatment is adopted to remove oil drops with the particle size of more than 100um in wastewater; removing the finely dispersed oil with the particle size of 10-100 um in the wastewater by coagulation air floatation; then ozone is used for oxidation to remove the residual COD in the wastewater; and then suspended matters in the sewage and COD in the adsorbed wastewater are removed by utilizing filtration and adsorption, so that a guarantee is provided for a subsequent nanofiltration system, pollutants in the sewage are reduced, and the effluent is ensured to meet the design requirements.

The treated effluent meets the standards of process and product water in the water quality of industrial water for urban sewage recycling (GB/T19923-2005).

3. Advantageous effects

Compared with the prior art, the invention has the beneficial effects that:

(1) The zero discharge treatment method for sewage in the filter production line provided by the invention adopts oil removal treatment, coagulation air flotation, softening coagulation, ozone oxidation, filtration and adsorption and nanofiltration, avoids the influence of heavy metals on biochemical treatment, has simple operation, stable daily operation and less dosage, and can meet the requirement of water quality of industrial water for urban sewage recycling (GB/T19923-2005);

(2) The concentrated water obtained by the SNF membrane component is cooled by the low-temperature evaporation concentrator, and the effluent can be recycled in a factory, so that the standard of the recycled water is achieved, and zero emission is realized;

(3) The invention filters the sludge generated in coagulation air flotation and softening coagulation by a plate-and-frame filter press, and the filtered sludge is subjected to external treatment, thereby facilitating the post-treatment of pollutants.

Drawings

The technical solution of the present invention will be described in further detail below with reference to the accompanying drawings and examples, but it should be understood that these drawings are designed for the purpose of illustration only and thus are not limiting the scope of the present invention. Moreover, unless specifically indicated otherwise, the drawings are intended to conceptually illustrate the structural configurations described herein and are not necessarily drawn to scale.

FIG. 1 is a flow chart of a sewage zero release treatment of a filter production line according to the present invention;

FIG. 2 is a schematic diagram of the oil removing unit structure of the present invention;

FIG. 3 is a schematic diagram of the structure of the reaction unit of the present invention;

FIG. 4 is a schematic diagram of a filter unit according to the present invention;

FIG. 5 is a schematic diagram of the water producing unit structure of the present invention;

FIG. 6 is a schematic diagram of a sludge treatment unit according to the present invention;

FIG. 7 is a schematic diagram of a concentrated water treatment unit according to the present invention;

100. deoiling unit: 110. an oil separation regulating tank;

200. and (3) a reaction unit: 210. an air floatation tank; 211. a cell body; 212. a gas dissolving device; 2121. a dissolved air tank; 2122. an air floatation dissolving air pump; 213. a slag scraping device; 214. a first stirring device; 215. a sludge pool;

220. softening the coagulation pool; 221. a reaction tank; 2211. a second stirring device; 222. a sedimentation tank; 230. an ozone catalytic oxidation pond; 231. an ozone generator; 232. an internal circulation pump;

300. And a filtering unit: 310. a multi-media filter; 320. raw water barrel; 330. an SNF membrane device; 331. an SNF booster pump; 332. a precision filter; 333. SNF high-pressure pump; 334. an SNF membrane module;

400. and (3) a water production unit: 410. a water producing tank; 411. a water pump is recycled;

500. dosing unit: 510. a first dosing tank; 520. a second dosing tank; 530. a third dosing tank; 540. a fourth dosing tank; 550. a fifth medicinal tank;

600. Sludge treatment unit: 610. a plate and frame filter press; 611. an air compressor; 612. a pneumatic diaphragm pump;

700. concentrated water treatment unit: 710. a concentrated water bucket; 720. concentrated water circulating bucket; 730. a low temperature evaporative concentrator; 740. and (5) a cooling tower.

Detailed Description

The following detailed description of exemplary embodiments of the invention refers to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration exemplary embodiments in which the invention may be practiced. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it is to be understood that other embodiments may be realized and that various changes to the invention may be made without departing from the spirit and scope of the invention. The following more detailed description of the embodiments of the invention is not intended to limit the scope of the invention, as claimed, but is merely illustrative and not limiting of the invention's features and characteristics in order to set forth the best mode of carrying out the invention and to sufficiently enable those skilled in the art to practice the invention. Accordingly, the scope of the invention is limited only by the attached claims.

The devices in the embodiments of the present invention are all commercially available products.

In the prior art, biochemical treatment is generally adopted for sewage treatment, but the biochemical treatment depends on the action of microorganisms, the microorganisms are greatly influenced by seasons, and the requirements on environment are high and the operation is unstable. The application aims at the sewage of the filter production line, has high concentration of heavy metals (iron, zinc and nickel), has poisoning effect on microorganisms, influences the sewage treatment effect, and has the advantages of no regeneration of the microorganisms and complex post-treatment process.

The application adopts the procedures of oil separation treatment, coagulation air flotation, softening coagulation, ozone oxidation, filtration, adsorption and nanofiltration for the treatment of sewage in a filter production line, and compared with the prior art, the application adopts a biochemical-free treatment method.

The sewage of the filter production line comprises 34-51 mg/L of oil, 0.043-1.10 mg/L of ammonia nitrogen, 0.18-0.29 mg/L of total phosphorus, 0.21-1.11 mg/L of iron ions, 0.05-0.24 mg/L of zinc ions, less than 0.05mg/L, COD-151 mg/L of nickel ions and 35.1mg/L of five-day biochemical oxygen demand, and firstly, oil drops with the particle size larger than 100nm in the sewage are removed by adopting oil separation treatment, so that the oil drops are prevented from wrapping subsequent pollutants and reagents, and the treatment load of the system is increased.

Further adding neutralizer, flocculant and coagulant aid, collecting suspended substances and colloid substances in water, and removing suspended substances, finely dispersed oil adsorbed on the suspended substances and partial COD by using the action of dissolved air and water. After these two steps, the oil content in the sewage is substantially removed.

And then, under the action of a softener, a flocculant and a coagulant aid, pollutants such as COD, suspended matters, heavy metals and the like in the wastewater are further precipitated and removed, most heavy metal ions are removed, and the hardness of the water is further reduced.

In order to further reduce the concentration of sewage passing through the nanofiltration membrane, the residual COD is subjected to strong oxidative degradation by ozone, the degraded sewage enters the multi-medium filter 310, the COD in the sewage entering the SNF membrane device 330 is controlled to be less than or equal to 60mg/L, and the influence of the excessive COD content on the nanofiltration membrane is avoided.

The examples are directed to filter production line sewage, the components and parameters of which are shown in table 1:

TABLE 1 composition and parameters of Filter production line Sewage

Component (A)	Concentration of
		Oil component	60～70mg/L
Suspension of	34～51mg/L
		Chemical Oxygen Demand (COD)	80～151mg/L
Five-day biochemical oxygen demand	35.1mg/L
		Ammonia nitrogen	0.043～1.10mg/L
Total phosphorus	0.18～0.29mg/L
		Iron (Fe)	0.21～1.11mg/L
Zinc alloy	0.05～0.24mg/L
		Nickel (Ni)	＜0.05mg/L

The invention is a treatment method aiming at sewage of a filter production line, the components of the sewage are shown in table 1, the sewage of the filter production line is characterized by poor biodegradability, high suspended matter concentration and large hardness, so the invention aims at the characteristics by selecting a mode of pretreatment and SNF membrane system, and finally the obtained produced water meets the standard requirements of process and product water in urban sewage recycling industrial water quality (GB/T19923-2005).

The agents present in the examples include: the mass concentration of the neutralizer is 10%;

the mass concentration of the flocculant is 0.1%;

the mass concentration of the coagulant aid is 10%;

the mass concentration of the softener is 10%;

The mass concentration of the scale inhibitor is 10%; wherein the scale inhibitor comprises an organic polymer, such as a small molecular organic polymer containing phosphorus;

The mass concentration of the reducing agent is 10%.

Example 1

The invention discloses a sewage zero discharge treatment method utilizing the filter production line, which comprises the following steps:

s1, oil removal treatment: the wastewater flows into the oil separation adjusting tank 110 through the pipe canal for oil separation treatment.

Wherein, the oil separation treatment utilizes the difference of specific gravity of suspended matters and water in the wastewater to achieve the purpose of separation. After the oily wastewater enters the oil removal regulating tank 110, the oily wastewater slowly flows along the horizontal direction, oil flows up to the floating surface in the flowing direction through the multi-lattice oil removal regulating tank 110, the water passing holes are arranged below the water surface, oil products and other impurities on the floating surface are convenient to be trapped, separated sewage enters the last lattice through the water passing holes, and then is lifted to the air floatation tank 210 through the oil removal regulating tank 110 lifting pump.

The original tank volume is 66m ³, the system water inflow is 30m ³/d, and the residence time of the wastewater in the oil separation adjusting tank 110 is controlled to be 2.2d.

S2, coagulation air floatation: the effluent of the oil separation regulating tank 110 is pumped to the air floatation tank 210, neutralizing agent, flocculating agent and coagulant aid are added, and under the action of the dissolved air water generated by the dissolved air tank 2121 and the air floatation dissolved air pump 2122, the oil substances, suspended matters, COD and other pollutants in the wastewater float up to the water surface to be removed by the slag scraping device 213.

Wherein the neutralizing agent is caustic soda flakes, and is introduced through the first dosing tank 510, and the flow rate is 100L/h; the flocculant is PAC and is introduced through a second dosing tank 520, and the flow rate is 100L/h; the coagulant aid is PAM, and is introduced through the third dosing tank 530 at a flow rate of 100L/h, and the air in the dissolved air tank 2121 at a flow rate of 300L/h.

The application firstly carries out oil separation treatment before reaction, oil in sewage of a filter production line comprises oil drops with the particle size of more than 100nm and finely dispersed oil with the particle size of 10-100 microns, wherein the oil drops with the particle size of more than 100nm are easy to float on a liquid surface and can be removed through the oil separation treatment, the finely dispersed oil with the particle size of 10-100 microns is mixed in the sewage to form an oil-water mixture, and in the subsequent precipitation reaction of coagulation air floatation, softening coagulation and ozone oxidation, the oil is adsorbed on the precipitation surface, so that the precipitation is difficult to enrich, flocculation precipitation is influenced, and the oil is adsorbed on the surface of a device, so that the subsequent sewage treatment is difficult to clean.

S3, softening and coagulating: the clarified effluent of the air floatation tank 210 flows into a softening coagulation tank 220, and under the action of a softener, a flocculant and a coagulant aid, pollutants such as COD, suspended matters, heavy metals and the like in the wastewater are further precipitated and removed, so that the hardness of the water is reduced, the metal ions in the concentrated solution subjected to membrane filtration at last are reduced, and the amount of the concentrated solution is reduced.

Wherein the softening agent is sodium carbonate, and is introduced through the fifth medicine adding tank 550, and the flow rate is 100L/h;

The flocculant is PAC and is introduced through a second dosing tank 520, and the flow rate is 100L/h;

the coagulant aid is PAM and is introduced through the third dosing tank 530 at a flow rate of 100L/h.

The water conservancy of the softening and coagulating sedimentation tank 222 accords with 0.5m ³/(m² h).

S4, ozone oxidation: the supernatant effluent from the sedimentation tank 222 flows into an ozone catalytic oxidation tank 230, and the ozone generated by an ozone generator 231 is used for carrying out strong oxidation removal on the refractory substances in the wastewater.

Wherein, the ozone catalytic oxidation tank 230 is provided with an ozone generator 231, and ozone is used for generating high oxidation-reduction potential OH, the addition amount is 100g/h, the reaction time is 2h, and the ozone catalytic oxidation tank is subjected to complexation reaction with organic pollutants in water to enrich the organic matters, thereby accelerating the oxidative decomposition speed of the organic matters, and degrading and oxidatively decomposing the organic matters.

S5, filtering and adsorbing: the effluent of the ozone catalytic oxidation tank 230 is pumped by a water inlet pump to a multi-medium filter 310 to filter and adsorb micro suspended matters, so that the stable operation of a post-treatment system is ensured.

The medium in the multi-medium filter 310 is that, during the screening process of the multi-medium filter 310, when the water flows through the filter material layer, larger particles and suspended matters are intercepted deep in the filter material, and smaller particles and dissolved matters can pass through the filter material layer. In the adsorption process, the micro pore canal of the adsorption filter material such as activated carbon can adsorb organic substances, chlorine, peculiar smell and other harmful substances in water, so that the water quality is better purified.

S6, nanofiltration: the effluent of the multi-medium filter 310 enters the SNF membrane device 330 to remove pollutants such as COD, ammonia nitrogen, divalent salt and the like in the wastewater, and the produced water of the SNF membrane system can reach the standard for recycling after entering the water producing tank. Wherein the pressure of the SNF membrane device 330 is 1.5MPa, and the flow rate is 3m ³/h. The removal rates of COD, ammonia nitrogen and total phosphorus of the sewage in the SNF membrane system are respectively 70%, 60% and 99%.

After the treatment, the sludge scraped by the slag scraping device 213 of the air floatation tank 210 and the sludge precipitated to the bottom in the sedimentation tank 222 are introduced into the plate-and-frame filter press 610 from the sludge tank 215, and are dehydrated, and the dehydrated sludge is subjected to external treatment.

The concentrated water filtered by the SNF film device 330 is introduced into a concentrated water circulation bucket 720, sequentially passes through a low-temperature evaporation concentrator 730 and a cooling tower 740, and is subjected to salt precipitation at low temperature, and the temperature is controlled at 180 ℃.

The SNF membrane system is used as a novel membrane separation technology, and the technical principle is similar to mechanical screening. Under the action of the driving force of pressure difference, salt and small molecular substances pass through the nanofiltration membrane to intercept large molecular substances. The molecular weight cut-off of the nanofiltration membrane is in the range of 200-1000MWCO and is between ultrafiltration and reverse osmosis, and the nanofiltration membrane is mainly used for concentrating and purifying macromolecular substances in solution. By utilizing the characteristic that nanofiltration has higher retention rate on divalent salt and higher transmittance on monovalent salt, partial salt mixing materials are subjected to salt separation treatment.

The final produced water meets the standard requirements of the process and the product water in the urban sewage recycling industrial water quality (GB/T19923-2005), and the indexes are shown in the table 2.

TABLE 2 Components and parameters of treated produced Water

It is worth noting that the application realizes zero discharge of sewage, the sewage treated by the SNF membrane device 330 is produced water reaching the standard and filtered concentrated water, wherein the produced water reaching the standard can be recycled, and can also be directly discharged, and the concentrated water enters the concentrated water treatment unit 700 to be evaporated and concentrated at low temperature, and the produced water reaches the standard after salt is separated out.

The method for treating the sewage of the filter production line has the advantages of short process, simple operation and low running cost.

Example 2

In the operation process, the SNF membrane device needs to be cleaned regularly, or pollutants in the device are deposited excessively, so that the membrane is prevented from being blocked by the pollutants to influence the reaction process, and the membrane is cleaned by adopting a scale inhibitor and a reducing agent. During cleaning, the sewage is stopped from being introduced into the SNF membrane device, in the embodiment, the phosphorus-containing organic polymer is used as a scale inhibitor, sodium bisulphite is used as a reducing agent, and the adding mass of the scale inhibitor and the reducing agent is 1:1.

Example 3

The utility model provides a filter production line sewage zero release processing apparatus, includes deoiling unit 100, reaction unit 200, filtration unit 300, produces water unit 400, dosing unit 500, sludge treatment unit 600 and dense water treatment unit 700, deoiling unit 100, reaction unit 200, filtration unit 300 and produce water unit 400 connect gradually, dosing unit 500 is connected with reaction unit 200 and filtration unit 300 respectively, sludge treatment unit 600 is connected with reaction unit 200 and filtration unit 300 respectively, dense water treatment unit 700 is connected with filtration unit 300 rear end.

The oil removal unit 100 includes an oil removal regulating tank 110, and the oil removal regulating tank 110 is provided with a lift pump for inputting sewage into the reaction unit 200. The oil separation regulating tank 110 is a multi-lattice oil separation regulating tank 110 with rectangular plane, and is provided with a plurality of tank bodies, the side wall of the oil separation regulating tank 110 is provided with water passing holes, and the water passing holes are arranged below the liquid level. The sewage flows between the adjacent oil separation regulating tanks 110 through the water passing holes. The oil separation adjusting tank 110 is used for removing a large volume of suspended matters and oil floating on the surface in sewage, and then is lifted to the air floatation tank 210 for treatment by a lifting pump through a pipeline.

The oil removal unit 100 comprises an oil removal adjusting tank 110, wherein the oil removal adjusting tank 110 is a multi-lattice oil removal adjusting tank 110 with a rectangular plane, a plurality of tank bodies are arranged on the oil removal adjusting tank 110, water passing holes are formed in the side walls of the oil removal adjusting tank 110, and wastewater flows among the oil removal adjusting tanks 110 through the water passing holes.

The reaction unit 200 comprises an air floatation tank 210, a softening coagulation tank 220 and an ozone catalytic oxidation tank 230 which are sequentially connected.

The air floatation tank 210 comprises a tank body 211 and an air dissolving device 212, the air dissolving device 212 comprises an air dissolving tank 2121, an air floatation air dissolving pump 2122 is arranged on a pipeline between the air dissolving tank 2121 and the tank body 211, the air floatation air dissolving pump 2122 pressurizes and introduces the air in the air dissolving tank 2121 into the tank body 211, the air floatation air dissolving pump 2122 is utilized to stir the air and the solution at a high speed, a large number of tiny bubbles are formed, the tiny bubbles are attached to the pollutant formed by coagulation, and the pollutant floats to the surface. Still be equipped with in the air supporting pond 210 and scrape sediment device 213, scrape sediment device 213 includes at least one and scrape the sediment board, it is located the air supporting pond 210 liquid level to scrape the sediment board through drive arrangement operation, will float on the impurity on the surface constantly and scrape to in the sludge impoundment 610 for more the unnecessary suspended solid and the oil content in the deep removal water. The treated sewage overflows from the pipe to the softening and coagulation tank 220. A sludge tank 215 is arranged below the floatation tank 210 and is used for receiving impurities scraped by the scraping plate.

The softening and coagulating tank 220 comprises a reaction tank 221 and a sedimentation tank 222, the reaction tank 221 and the sedimentation tank 222 are isolated by a baffle, water passing holes are formed in the baffle, wastewater flows between the reaction tank 221 and the sedimentation tank 222 through the water passing holes, the sedimentation tank 222 is used for carrying out gravity sedimentation on flocculent precipitate generated by the reaction tank 221, and the lower part of the flocculent precipitate is connected with the sludge tank 215 through a pipeline. The reaction tank 221 is provided with a first stirring device 214 for uniformly mixing the wastewater and the reaction reagent, the sedimentation tank 222 is internally provided with inclined pipes which are parallel to each other, the inclined pipes are preferably made of PP materials, the wastewater and the reaction reagent in the sedimentation tank 222 are partitioned by the inclined pipes, sedimentation accumulation and enrichment are reduced, and sedimentation efficiency is affected. The 2-valence metal ions in the sewage are removed, so that the hardness of the sewage is reduced. The supernatant after the precipitation separation overflows to the ozone catalytic oxidation tank 230 through an overflow weir.

The ozone catalytic oxidation tank 230 is isolated from the sedimentation tank 222 by a baffle, an overflow weir is arranged on the upper portion of the baffle, an ozone generator 231 is arranged in the ozone catalytic oxidation tank 230 and is used for oxidizing and removing organic matters, and residual organic matters in sewage are oxidized by the strong oxidizing property of ozone so as to reach the standard of reuse water. The ozone catalytic oxidation pond 230 is connected with an internal circulation pump 232, circulates through the internal circulation pump 232, and enables ozone and sewage to fully react, so that the treatment efficiency is improved. Finally, the treated sewage enters the filtering unit 300 to be filtered.

The filtering unit 300 comprises a multi-medium filter 310 and an SNF membrane device 330 which are sequentially connected, the multi-medium filter 310 comprises a cylinder body which is sequentially connected, a filter material is arranged in the cylinder body, the filter material can be quartz sand, anthracite, active carbon, magnetite, garnet, porous ceramic, plastic balls and the like, the filtering and the adsorption of micro suspended matters are realized, and the stable operation of a rear-stage treatment system is ensured. In embodiment 1, the multi-medium filter 310 comprises two tanks connected in sequence, wherein the medium in the first tank is quartz sand with different gaps, the medium in the second tank is activated carbon with different meshes, the quartz sand is used for filtering suspended matters in water, and the activated carbon is used for adsorbing organic matters and heavy metals.

The SNF membrane device 330 comprises a precision filter 332 and an SNF membrane module 334, and is used for removing pollutants such as COD, ammonia nitrogen, divalent salt and the like in the wastewater, and the produced water of the SNF membrane system can reach the standard for recycling after entering a produced water tank. The SNF booster pump 331 is disposed in front of the fine filter 332 and is used for boosting the water entering the fine filter 332, and the SNF high-pressure pump 333 is disposed in front of the SNF membrane module 334 and is used for boosting the water entering the SNF membrane module 334.

A raw water bucket 320 is arranged between the multi-medium filter 310 and the SNF membrane device 330, and water after ozone catalytic oxidation is stored. Since the ozone-catalyzed oxidized water needs to pass through the multi-medium filter 310 and the multi-medium filter 310 cannot be directly connected with a subsequent system, a raw water tank 320 is provided for storing the ozone-catalyzed oxidized water. Meanwhile, the effluent of ozone catalytic oxidation needs to stay for a certain time, so that the subsequent inflow water quality is ensured to be stable.

The SNF membrane device 330 is connected with a water production tank 410, and the produced water meeting the recycled water standard is recycled in the production process through a recycled water pump 411.

The dosing unit 500 comprises a plurality of dosing tanks, wherein the dosing tanks comprise a first dosing tank filled with a neutralizing agent, a second dosing tank filled with a flocculating agent, a third dosing tank filled with a coagulant aid, a fourth dosing tank filled with a softening agent, a fourth dosing tank filled with a scale inhibitor and a sixth dosing tank filled with a reducing agent, the first dosing tank is connected with an air floatation tank, the second dosing tank is respectively connected with the air floatation tank 210 and the softening coagulation tank 220, the third dosing tank is respectively connected with the air floatation tank 210 and the softening coagulation tank 220, the fourth dosing tank is connected with the softening coagulation tank 220, the fifth dosing tank and the sixth dosing tank are connected with the SNF membrane device 330, and valves are arranged on dosing pipelines of the dosing tanks for controlling dosing flow.

The sludge treatment unit 600 includes a plate-and-frame filter press 610, wherein the plate-and-frame filter press 620 is connected to the sludge tank 215, and the plate-and-frame filter press 620 filters the sludge to obtain the sludge, which is treated outside the sludge. Furthermore, in the plate and frame filter pressing process, the pneumatic diaphragm pump 612 is driven by the air compressor 611 to realize rapid filter pressing of sludge.

The concentrated water treatment unit 700 includes a concentrated water bucket 710, the concentrated water bucket 710 is connected with the SNF membrane module 334, receives concentrated water treated by the SNF membrane module 334, one end of the concentrated water bucket 710 is connected with the air floatation tank 210, and a part of concentrated water in the concentrated water bucket 710 is introduced into the air floatation tank 210 and is reprocessed by the reaction unit 200 and the filtration unit 300. The other end of the concentrated water bucket 710 is connected with a concentrated water circulating water bucket 720, when the system is overloaded and cannot bear the reprocessing of the concentrated water, the concentrated water in the concentrated water bucket 710 is introduced into the concentrated water circulating water bucket 720, the concentrated water circulating water bucket 720 is sequentially connected with a low-temperature evaporation concentrator 730 and a cooling tower 740, and in the processing process, the concentrated water is cooled by the low-temperature evaporation concentrator 730, salt is separated out at low temperature, and the temperature is controlled to be about 180 ℃.

Wherein, the air floatation tank 210 is provided with a first stirring device 214, and the reaction tank 221 is provided with a second stirring device 2211 for uniformly mixing reactants;

the floatation tank 210 is provided with an on-line pH meter, and the pH of the wastewater in the reaction unit 200 is controlled to be 7-8.

Claims

1. A sewage zero discharge treatment method for a filter production line is characterized by comprising the following steps:

s1, oil removal treatment;

S2, coagulation air floatation: adding a neutralizing agent, a flocculating agent and a coagulant aid, and introducing air;

s3, softening and coagulating: adding a softening agent, a flocculating agent and a coagulant aid;

S4, performing ozone oxidation;

S5, adsorbing and filtering;

S6, nanofiltration;

the sewage of the filter production line comprises 0.21-1.11 mg/L of iron, 0.05-0.24 mg/L of zinc and less than 0.05mg/L of nickel.

2. The method for zero-emission treatment of filter production line sewage according to claim 1, wherein the filter production line sewage further comprises suspended matters 34-51 mg/L, ammonia nitrogen 0.043-1.10 mg/L, COD-151 mg/L, total phosphorus 0.18-0.29 mg/L, and oil 60-70 mg/L.

3. The method for zero-emission treatment of filter production line sewage according to claim 1, wherein the neutralizing agent comprises one or more of caustic soda flakes, lime and sodium carbonate; the flocculant comprises one or more of PAC, aluminum sulfate and ferrous chloride; the coagulant aid comprises one or more of PAM, PCE and biological glue; the softening agent comprises one or more of sodium carbonate, quicklime and slaked lime.

4. The method for zero discharge treatment of wastewater in a filter production line according to claim 1, wherein the pH of the wastewater in step S2 is controlled to be 7 to 8.

5. The method for zero discharge treatment of sewage in a filter production line according to claim 4, wherein the flow ratio of the neutralizer, the flocculant, the coagulant aid and the sewage in the step S2 is 1:1:1 (5-10).

6. The method for zero discharge treatment of sewage in a filter production line according to claim 1, wherein the flow ratio of the softener, the flocculant, the coagulant aid and the sewage in the step S3 is 1:1:1 (5-10).

7. The method for zero discharge treatment of sewage from a filter production line according to claim 1, further comprising a sludge treatment step of filtering sludge generated in coagulation air flotation and softening coagulation by a plate and frame filter press.

8. The method for zero discharge treatment of sewage from a filter production line according to claim 1, further comprising a concentrated water treatment step of filtering the obtained concentrated water, cooling the concentrated water by using a low-temperature evaporation concentrator, and precipitating salt at 160-200 ℃.

9. The method for zero discharge treatment of sewage in a filter production line according to claim 1, wherein the removal rates of COD, ammonia nitrogen and total phosphorus in the sewage obtained in the step S6 are respectively 60% -70%, 55% -60% and 98% -99%.

10. A device for realizing the method according to any one of claims 1-9, comprising an oil removal unit (100), a reaction unit (200), a filtering unit (300), a water production unit (400), a dosing unit (500), a sludge treatment unit (600) and a concentrate treatment unit (700), wherein the oil removal unit (100), the reaction unit (200), the filtering unit (300) and the water production unit (400) are sequentially connected, the dosing unit (500) is respectively connected with the reaction unit (200) and the filtering unit (300), the sludge treatment unit (600) is respectively connected with the reaction unit (200) and the filtering unit (300), and the concentrate treatment unit (700) is connected with the rear end of the filtering unit (300).