CN110818191A - Application of printing and dyeing wastewater pretreatment process - Google Patents

Abstract

The invention discloses a pretreatment process of printing and dyeing wastewater, which specifically comprises the following steps: s1, performing flocculation reaction in a flocculation device, S2, entering a horizontal flow sedimentation tank, making supernatant fluid flow into an overflow water collecting tank, scraping sludge into a sludge hopper, performing oxidation treatment in an ozone oxidation tank at S3, and performing biochemical treatment in an A/0 tank at S4, and the invention relates to the technical field of wastewater treatment. This printing and dyeing wastewater pretreatment process's application, can reduce biochemical section's the load of intaking, printing and dyeing wastewater ozone oxidation preliminary treatment can be with the organic dyestuff oxidative decomposition of macromolecule difficult degradation for the small molecule pollutant of easy biological treatment, and required ozone concentration is lower, contain dissolved oxygen in the waste water after ozone oxidation preliminary treatment, can realize follow-up biochemical treatment's preliminary filling oxygen, reduce follow-up biochemical section's aeration rate, energy saving, can improve waste water biochemical nature again, it is big to avoid traditional anaerobic hydrolysis pretreatment process cell body area, the influence of the foul pollution that anaerobic sludge brought.

Description

Application of printing and dyeing wastewater pretreatment process

Technical Field

The invention relates to the technical field of wastewater treatment, in particular to a printing and dyeing wastewater pretreatment process by alkaline chemical flocculation and precipitation and ozone oxidation.

Background

The textile printing and dyeing wastewater has the characteristics of large water quantity, high organic pollutant content, large alkalinity, large water quality change and the like, belongs to one of industrial wastewater difficult to treat, contains dye, slurry, auxiliary agent, oil agent, acid and alkali, fiber impurities, sand substances, inorganic salt and the like, and the main methods for treating the printing and dyeing wastewater comprise a physicochemical method, a biochemical method, a chemical method and a treatment method combining a plurality of processes.

Because the quality of the printing and dyeing wastewater is complex, pollutants can be divided into two types according to sources: a type of entrainment from the fibrous material itself; the other is slurry, oil, dye, chemical assistant, etc. used in the processing course, because the dye has many varieties and develops towards photolysis resistance, oxidation resistance and biological oxidation resistance, the treatment difficulty of the dye waste water is increased, and the treatment difficulty of the dye waste water is difficult: firstly, COD is high, and BOD/COD value is less, and biodegradability is poor, secondly the colourity is high, and the component is complicated, and the getting rid of COD has the relevance with the decoloration, and the decoloration degree of difficulty is bigger, in addition, because of the discontinuous operation of production, the fluctuation of the quality of water yield that so exists, to using a large amount of vat dyes, the waste water of sulphide dye, ice dyestuff etc. its chemical flocculation effect is fairly relatively poor, consequently, these factors need be considered to the waste water treatment technology, need be with the variable ability of certain adaptation quality of water, water volume load.

The common treatment method of the printing and dyeing wastewater can be divided into a physical method, a chemical method and a biochemical method, the physical method mainly comprises a grating, a screen, regulation, precipitation, air floatation, filtration, membrane technology and the like, the chemical method comprises neutralization, coagulation, electrolysis, oxidation, adsorption, disinfection and the like, the biological method comprises an anaerobic biological method, an aerobic biological method and a facultative biological method, the printing and dyeing wastewater treatment process is necessary, sufficient regulation time is necessary, the combination of physical chemistry and biochemical is the conventional reasonable process adopted at present, the physical chemical method is mainly used for removing suspended matters, chroma and part of COD, adding a flocculating agent is an important link of physical and chemical treatment, the separation process precipitation method is a common process, the biochemical method mainly adopts an anaerobic hydrolysis and aerobic biochemical series process, the anaerobic hydrolysis process mainly solves the pretreatment processes of high COD, poor biodegradability and high chroma, most of difficultly degraded organic matters after the anaerobic hydrolysis are decomposed into easily degradable small molecular organic matters, can improve the biodegradability of waste water, the good oxygen biochemical treatment's of guarantee waste water efficiency and play water quality of water quality, but the general printing and dyeing wastewater of current printing and dyeing wastewater treatment process is intake high, and main suspended matter is high, and COD is high, and the biodegradability is poor, and the colourity is high, can not reach better treatment effect, and is higher to the purity requirement of ozone, and the energy consumption is higher.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides the application of the pretreatment process of the printing and dyeing wastewater, and solves the problems of high main suspended matter, high COD, poor biodegradability, high chromaticity, poor treatment effect, higher requirement on the purity of ozone and higher energy consumption.

(II) technical scheme

In order to achieve the purpose, the invention is realized by the following technical scheme: a pretreatment process for printing and dyeing wastewater specifically comprises the following steps:

s1, firstly, detecting ss and COD of inlet water, adjusting a dosing device according to the dosing amount and dosing proportion corresponding to a dosing curve confirmed in a laboratory, adding a quicklime suspension at the water inlet of a flocculation tank, mixing the medicament and raw water in a rapid coagulation stirring reaction tank to generate flocculation reaction, sequentially passing through the rapid stirring tank and a mixing plug flow tank, adding anion PAM at the inlet of the mixing plug flow tank to assist coagulation, increasing the particle size of the floc in the turbulent flow of water flow to form alum floc, and distributing the water flow in a water distribution tank to enter a horizontal flow sedimentation tank;

s2, allowing the wastewater entering the horizontal sedimentation tank to undergo sedimentation separation in a slurry-liquid two-phase flow, allowing the flocculated wastewater to enter the horizontal sedimentation tank after turning over a water distribution weir, slowing down the flow rate and allowing the flocculated wastewater to stably flow to an outlet, allowing the flocculated wastewater to sink to a sludge area at the bottom of the tank under the action of gravity and net capture in the slow flow of water, allowing supernatant to flow into an overflow water collection tank at the water outlet end of the tank body, scraping the sludge into a sludge hopper by a sludge scraper, and pumping residual sludge from the bottom of the sludge hopper by a sludge pump to discharge the residual sludge into a sludge treatment system;

s3, enabling the wastewater flowing out of the overflow water collecting tank in the step S2 to enter an ozone oxidation tank, introducing ozone through an ozone generator at the inlet of the ozone oxidation tank, carrying out contact oxidation reaction on the ozone generated by the ozone generator and the alkaline wastewater in an ozone reactor for 10-20 minutes, and then enabling the wastewater to enter an ozone destruction tank to eliminate residual unreacted ozone;

s4, the wastewater treated in the step S3 directly enters an A/0 pool for biochemical treatment.

Preferably, the dosing device, the rapid stirring tank and the mixing plug-flow tank in the step S1, and the horizontal flow sedimentation tank and the overflow water collecting tank in the step S2 all belong to a flocculation device.

Preferably, the ozone oxidation pond and the ozone destruction pond in the step S3 belong to an ozone oxidation device, and the A/O pond in the step S4 belongs to a biochemical treatment device.

Preferably, in the step S1, the water inlet of the rapid stirring tank is communicated with a water inlet pipe, and the surface of the water inlet pipe is communicated with the drug outlet of the drug adding device through a connecting pipe.

Preferably, the sludge treatment system in the step S2 includes a sludge pump room and a sludge storage tank, and the sludge inlet of the sludge storage tank is communicated with the sludge outlet of the sludge pump room through a conduit.

Preferably, the water outlet of the ozone destruction pool is communicated with the water inlet of the A/O pool through a conveying pipe.

The invention also discloses an application of the printing and dyeing wastewater pretreatment process in a printing and dyeing wastewater treatment plant, which comprises the following steps:

after floating objects are removed from certain textile printing and dyeing wastewater in a certain sewage treatment plant through a coarse and fine grid, the textile printing and dyeing wastewater enters an adjusting tank to balance water quality and water quantity, the printing and dyeing wastewater enters a flocculation device to react and then remove part of suspended matters, COD (chemical oxygen demand) and total phosphorus, then enters an ozone oxidation device to be pretreated through ozone oxidation, enters an A/O (anoxic/oxic) tank to be subjected to biochemical treatment, and part of the discharged water enters an advanced treatment system to be treated and is recycled to upstream enterprises to be used as make-up water for production.

(III) advantageous effects

The invention provides an application of a pretreatment process of printing and dyeing wastewater. Compared with the prior art, the method has the following beneficial effects:

the pretreatment process of the printing and dyeing wastewater comprises the steps of S1, firstly detecting inlet water ss and COD, adjusting a dosing device according to the dosing amount and the dosing proportion corresponding to a dosing curve confirmed in a laboratory lab, adding a quicklime suspension at the water inlet of a flocculation tank, mixing the medicament and raw water in a rapid coagulation stirring reaction tank to generate a flocculation reaction, sequentially passing through the rapid stirring tank and a mixing plug flow tank, adding anionic PAM (polyacrylamide) at the inlet of the mixing plug flow tank to assist coagulation, increasing the particle size of flocs in the turbulent flow of water flow to form alum flocs, and distributing water flow in a water distribution tank to enter a horizontal flow sedimentation tank; s2, allowing the wastewater entering the horizontal sedimentation tank to undergo sedimentation separation in a slurry-liquid two-phase flow, allowing the flocculated wastewater to enter the horizontal sedimentation tank after turning over a water distribution weir, slowing down the flow rate and allowing the flocculated wastewater to stably flow to an outlet, allowing the flocculated wastewater to sink to a sludge area at the bottom of the tank under the action of gravity and net capture in the slow flow of water, allowing supernatant to flow into an overflow water collection tank at the water outlet end of the tank body, scraping the sludge into a sludge hopper by a sludge scraper, and pumping residual sludge from the bottom of the sludge hopper by a sludge pump to discharge the residual sludge into a sludge treatment system; s3, enabling the wastewater flowing out of the overflow water collecting tank in the step S2 to enter an ozone oxidation tank, introducing ozone through an ozone generator at the inlet of the ozone oxidation tank, carrying out contact oxidation reaction on the ozone generated by the ozone generator and the alkaline wastewater in an ozone reactor for 10-20 minutes, and then enabling the wastewater to enter an ozone destruction tank to eliminate residual unreacted ozone; s4, the wastewater treated in the step S3 directly enters an A/0 tank for biochemical treatment, in the treatment process, the printing and dyeing wastewater can reduce the inflow inorganic COD, suspended matters and total phosphorus after flocculation pretreatment, the inflow load of a biochemical section is reduced, the printing and dyeing wastewater can oxidize and decompose macromolecular organic dye which is difficult to degrade into micromolecular pollutants which are easy to be biologically treated by ozone oxidation pretreatment, the required ozone concentration is low, the wastewater after ozone oxidation pretreatment contains dissolved oxygen, pre-charging of subsequent biochemical treatment can be realized, the aeration quantity of the subsequent biochemical section is reduced, the energy consumption is saved, the biodegradability of the wastewater can be improved, and the influence of odor pollution caused by large occupied area of a tank body and anaerobic sludge in the traditional anaerobic hydrolysis pretreatment process is avoided.

Drawings

FIG. 1 is a schematic of the process of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, an embodiment of the present invention provides a technical solution: a pretreatment process for printing and dyeing wastewater specifically comprises the following steps:

s1, firstly detecting ss and COD of inlet water, adjusting a dosing device according to the dosing amount and dosing proportion corresponding to a dosing curve confirmed in a laboratory, adding quicklime suspension at the water inlet of a flocculation tank, adding flocculating agent which is quicklime, mixing with water to prepare suspension, having good flocculation and precipitation effects under alkaline conditions, adding the lime suspension into the inlet water through the dosing device, carrying out flocculation reaction on dye and oil under alkaline conditions, effectively relieving the problems of high inlet water load of printing and dyeing wastewater, high main suspension, high COD, poor biodegradability, high chromaticity and the like, mixing a medicament and raw water in a rapid coagulation stirring reaction tank to carry out flocculation reaction, sequentially passing through the rapid stirring tank and a mixing plug flow tank, adding anion PAM (polyacrylamide) at the inlet of the mixing plug flow tank to help coagulation, and increasing the particle size of the floc in the turbulent flow of water, alum floc is formed, water flow is distributed in a water distribution tank and enters a horizontal flow sedimentation tank, basic dye and auxiliary agent are contained in the printing and dyeing wastewater, the pH value is higher, the alkaline wastewater belongs to alkaline wastewater, the flocculation effect of quicklime suspension is greatly improved, and the floc is coarse and dense;

s2, allowing the wastewater entering the horizontal sedimentation tank to undergo sedimentation separation in a slurry-liquid two-phase flow, allowing the flocculated wastewater to enter the horizontal sedimentation tank after turning over a water distribution weir, slowing down the flow rate and allowing the flocculated wastewater to stably flow to an outlet, allowing the flocculated wastewater to sink to a sludge area at the bottom of the tank under the action of gravity and net capture in the slow flow of water, allowing supernatant to flow into an overflow water collection tank at the water outlet end of the tank body, scraping the sludge into a sludge hopper by a sludge scraper, and pumping residual sludge from the bottom of the sludge hopper by a sludge pump to discharge the residual sludge into a sludge treatment system;

s3, the wastewater flowing out of the overflow water collecting tank in the step S2 enters an ozone oxidation tank, meanwhile, ozone is introduced into an inlet of the ozone oxidation tank through an ozone generator, the ozone generated by the ozone generator and the alkaline wastewater are subjected to contact oxidation reaction in an ozone reactor, supernatant effluent after flocculation and precipitation enters an ozone oxidation device, under the alkaline condition, the strong oxidation effect of the ozone and generated hydroxyl radicals breaks molecular chain groups of macromolecules, the chromophoric groups of organic dyes are damaged, the decolorization effect is particularly obvious, macromolecular difficultly biodegradable substances are changed into easily degradable micromolecular substances, the biodegradability of the wastewater is improved, the subsequent aerobic biochemical treatment is facilitated, the normal operation of an aerobic biochemical process is ensured, the treatment efficiency is exerted, the reaction retention time is 10-20 minutes, and the wastewater enters an ozone destruction tank to eliminate residual ozone which is not reacted completely, ozone has strong oxidizability, can also finish the oxidation reaction instantly when the concentration is low, there is no secondary pollution, the organic matter of ozone in the printing and dyeing waste water, inorganic substance react very complicatedly, mainly direct reaction and ozone decomposition of ozone oxidation produce the indirect reaction of the hydroxyl free radical, under the alkaline condition, more favorable to the formation of hydroxyl free radical that ozone decomposes, under lower ozone concentration, printing and dyeing waste water and ozone contact the oxidation reaction, make the unsaturated bond in chromophoric group in the dye molecule break, does not need to oxidize completely and produce carbon dioxide and water, but oxidize and produce some intermediate products, some micromolecular easy biochemical acid and aldehydes organic matter, reach and degrade the organic matter, improve biochemical property and decoloration effect, accord with the water inlet condition of subsequent A/O biochemical treatment;

s4, the wastewater treated in the step S3 directly enters an A/0 pool for biochemical treatment, an AO process method is also called an anaerobic-aerobic process method, and A (anaerobic) is an anaerobic section and is used for nitrogen and phosphorus removal; o (oxic) is an aerobic section for removing organic matter from water.

In the invention, the dosing device, the rapid stirring tank and the mixing plug-flow tank in the step S1 and the horizontal flow sedimentation tank and the overflow water collecting tank in the step S2 all belong to flocculation devices.

In the present invention, the ozone oxidation tank and the ozone destruction tank in step S3 both belong to the ozone oxidation apparatus, and the A/O tank in step S4 belongs to the biochemical treatment apparatus.

In the invention, the water inlet of the rapid stirring tank in the step S1 is communicated with a water inlet pipe, and the surface of the water inlet pipe is communicated with the medicine outlet of the medicine adding device through a connecting pipe.

In the invention, the sludge treatment system in the step S2 comprises a sludge pump room and a sludge storage tank, and a sludge inlet of the sludge storage tank is communicated with a sludge outlet of the sludge pump room through a conduit.

In the invention, the water outlet of the ozone destruction pool is communicated with the water inlet of the A/O pool through a conveying pipe.

The invention also discloses an application of the printing and dyeing wastewater pretreatment process, which is characterized by comprising the following steps: the application of the dye in a printing and dyeing wastewater treatment plant is as follows:

introducing certain textile printing and dyeing wastewater into a certain sewage treatment plant, removing floaters through a coarse-fine grid, then entering an adjusting tank to balance water quality and water quantity, removing part of suspended matters, COD (chemical oxygen demand) and total phosphorus after the printing and dyeing wastewater enters a flocculation device for reaction, then entering an ozone oxidation device for pretreatment through ozone oxidation, entering an A/O (anoxic/oxic) tank for biochemical treatment, and after the effluent enters an advanced treatment system for treatment, recycling part of the effluent to upstream enterprises as make-up water for production

Discharging certain printing and dyeing wastewater into a sewage treatment plant, treating the wastewater by a coarse and fine grid, and selecting two-day indexes to prepare a table as follows:

8 month and 9 days	COD(mg/L)	BOD(mg/L)	B/C	SS(mg/L)	Total phosphorus (mg/L)
						Inflow water	1260	152	12％	386	5.874
Water is discharged after flocculation and precipitation	786	133	17％	124	2.682
						Yielding water after ozone oxidation	660	243	32％	105	2.443
8 month and 13 days	COD(mg/L)	B(mg/L)	B/C	SS(mg/L)	Total phosphorus (mg/L)
						Inflow water	1740	194	11％	467	7.323
Water is discharged after flocculation and precipitation	1073	168	16％	194	3.545
						Yielding water after ozone oxidation	757	265	35％	142	3.243

The result shows that after the printing and dyeing wastewater passes through the pretreatment process, the operation parameters of two kinds of water inlet loads, namely a middle water inlet load and a high water inlet load, of a sewage plant in a normal operation period are selected for comparison, in different water inlet loads, the process can stably operate, the process is simple and easy to adjust, the treatment effect is good, after the printing and dyeing wastewater is subjected to flocculation pretreatment, the water inlet inorganic COD (chemical oxygen demand), suspended matters and total phosphorus of a biochemical section can be reduced, the ozone concentration required by the ozone oxidation pretreatment of the printing and dyeing wastewater is low, the wastewater after the ozone oxidation pretreatment contains dissolved oxygen, the pre-charging of subsequent biochemical treatment can be realized, the aeration quantity of the subsequent biochemical section is reduced, the energy consumption is saved, the biodegradability of the wastewater can be improved, and the influence of odor pollution caused by the anaerobic sludge and the large occupied area of a traditional anaerobic.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (7)

1. A pretreatment process of printing and dyeing wastewater is characterized in that: the method specifically comprises the following steps:

s1, firstly, detecting ss and COD of inlet water, adjusting a dosing device according to the dosing amount and dosing proportion corresponding to a dosing curve confirmed in a laboratory, adding a quicklime suspension at the water inlet of a flocculation tank, mixing the medicament and raw water in a rapid coagulation stirring reaction tank to generate flocculation reaction, sequentially passing through the rapid stirring tank and a mixing plug flow tank, adding anion PAM at the inlet of the mixing plug flow tank to assist coagulation, increasing the particle size of the floc in the turbulent flow of water flow to form alum floc, and distributing the water flow in a water distribution tank to enter a horizontal flow sedimentation tank;

s2, allowing the wastewater entering the horizontal sedimentation tank to undergo sedimentation separation in a slurry-liquid two-phase flow, allowing the flocculated wastewater to enter the horizontal sedimentation tank after turning over a water distribution weir, slowing down the flow rate and allowing the flocculated wastewater to stably flow to an outlet, allowing the flocculated wastewater to sink to a sludge area at the bottom of the tank under the action of gravity and net capture in the slow flow of water, allowing supernatant to flow into an overflow water collection tank at the water outlet end of the tank body, scraping the sludge into a sludge hopper by a sludge scraper, and pumping residual sludge from the bottom of the sludge hopper by a sludge pump to discharge the residual sludge into a sludge treatment system;

s3, enabling the wastewater flowing out of the overflow water collecting tank in the step S2 to enter an ozone oxidation tank, introducing ozone through an ozone generator at the inlet of the ozone oxidation tank, carrying out contact oxidation reaction on the ozone generated by the ozone generator and the alkaline wastewater in an ozone reactor for 10-20 minutes, and then enabling the wastewater to enter an ozone destruction tank to eliminate residual unreacted ozone;

s4, the wastewater treated in the step S3 directly enters an A/0 pool for biochemical treatment.

2. The pretreatment process of printing and dyeing wastewater according to claim 1, characterized in that: and the dosing device, the rapid stirring tank and the mixed plug-flow tank in the step S1 and the horizontal flow sedimentation tank and the overflow water collecting tank in the step S2 belong to flocculation devices.

3. The pretreatment process of printing and dyeing wastewater according to claim 1, characterized in that: the ozone oxidation pond and the ozone destruction pond in the step S3 belong to ozone oxidation devices, and the A/O pond in the step S4 belongs to biochemical treatment devices.

4. The pretreatment process of printing and dyeing wastewater according to claim 1, characterized in that: and in the step S1, the water inlet of the rapid stirring tank is communicated with a water inlet pipe, and the surface of the water inlet pipe is communicated with the medicine outlet of the medicine adding device through a connecting pipe.

5. The pretreatment process of printing and dyeing wastewater according to claim 1, characterized in that: the sludge treatment system in the step S2 comprises a sludge pump room and a sludge storage pool, and a sludge inlet of the sludge storage pool is communicated with a sludge outlet of the sludge pump room through a conduit.

6. The pretreatment process of printing and dyeing wastewater according to claim 1, characterized in that: and the water outlet of the ozone destruction pool is communicated with the water inlet of the A/O pool through a conveying pipe.

7. The application of the pretreatment process of the printing and dyeing wastewater is characterized in that: the application of the method in the treatment of printing and dyeing wastewater is as follows:

after floating objects are removed from certain textile printing and dyeing wastewater in a certain sewage treatment plant through a coarse and fine grid, the textile printing and dyeing wastewater enters an adjusting tank to balance water quality and water quantity, the printing and dyeing wastewater enters a flocculation device to react and then remove part of suspended matters, COD (chemical oxygen demand) and total phosphorus, then enters an ozone oxidation device to be pretreated through ozone oxidation, enters an A/O (anoxic/oxic) tank to be subjected to biochemical treatment, and part of the discharged water enters an advanced treatment system to be treated and is recycled to upstream enterprises to be used as make-up water for production.

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