CN113200650A

CN113200650A - Method and device for treating surfactant wastewater

Info

Publication number: CN113200650A
Application number: CN202110439891.0A
Authority: CN
Inventors: 赵一莲; 郑乐平
Original assignee: University of Shanghai for Science and Technology
Current assignee: University of Shanghai for Science and Technology
Priority date: 2021-04-23
Filing date: 2021-04-23
Publication date: 2021-08-03

Abstract

The invention discloses a surfactant wastewater combined treatment process and a device, wherein the main technical path for treating wastewater is a hydrolytic acidification and biochemical method, and MBR and activated carbon adsorption are adopted for advanced treatment. The treatment system comprises a water collecting tank, a rotary drum fine grid, a cooling tower, an adjusting tank, a hydrolysis acidification tank, a biochemical tank, an MBR membrane tank, an activated carbon adsorption tower, a clean water tank, a deoxidation tank and a sludge storage tank. The water collecting tank, the rotary drum fine grid, the cooling tower, the regulating tank, the hydrolysis acidification tank, the biochemical tank and the MBR membrane tank are sequentially connected, and then the effluent of the membrane tank is discharged outside or flows into a clean water tank through an active carbon adsorption tower for recycling; and after passing through the deoxidation tank, part of the sludge in the membrane tank flows back to the hydrolysis acidification tank, and part of the sludge is discharged into the sludge storage tank for filter pressing and outward transportation. The method has the advantages of simple process, small occupied area, high COD removal rate, capability of reaching the reuse standard of water quality, further cost saving, suitability for treating the surfactant wastewater by small and medium-sized linen washing enterprises, and good application prospect.

Description

Method and device for treating surfactant wastewater

Technical Field

The invention relates to the technical field of water treatment and resource recycling, in particular to a surfactant wastewater combined treatment process and a surfactant wastewater combined treatment device.

Background

With the development of the third industry in China, particularly the service industries such as hotels, catering, cultural entertainment and the like, chain hotels expand at a speed of about 30 percent, so that the requirements of washing services of bedsheets, quilt covers, bath towels, tablecloths and the like (short for linen) in the hotels are promoted. Meanwhile, the abundance of washing chemicals and the independent research and development of washing equipment in China promote the rapid development of the textile washing service industry, and a continuously perfect washing industry system is gradually formed. However, most linen washing plants in China cannot meet the environmental protection requirement at present, and backward production processes and equipment with high energy consumption and high pollution are still adopted in the washing operation. Washing is used as high water consumption operation, the recycling technology of washing water is not mature and popularized, the industrial wastewater discharge does not reach the standard, waste of water resources is inevitably caused, pollution is caused to air, soil and water environment, and harm is caused to human health.

The washing process of linen washing is generally divided into five steps of a preparation stage (soaking and prewashing), a core decontamination stage (main washing and bleaching), a rinsing stage (rinsing), a post-treatment stage (neutralization, softening and whitening) and a dehydration stage, and is shown in figure 1. The method comprises the following specific steps:

1) pre-washing: the sorted linen is soaked in cold water and pre-washed for 2 to 3 minutes without adding chemicals. Fabrics and soils are wetted by water and the bonding between the soils and fabric fibers is broken under the impact of water, and newly contaminated soils, water-soluble soils such as salt, sugar and the like, and some solid particulate soils such as sand, dust and the like can be partially or completely removed at this stage. The stage saves the dosage of the detergent for the main washing stage, is beneficial to subsequent rinsing and improves the washing effect. However, the whole time is not suitable to be too long to prevent color cross.

2) Main washing: and (4) putting the clothes which are pre-washed into a mechanical roller, wherein the loading amount is controlled to be 85%. Adding proper amount of water, adding detergent from the feeding port of the machine, starting the heating washing switch to reach washing temperature of 70-80 deg.c, and washing at low water level for 6-12 min to complete the main washing process. In the stage, most of the polluted dirt can be separated from the linen fabric, and then the polluted dirt is dissolved, emulsified, dispersed or suspended in the washing liquid; and a small part of dirt which is not separated enters a second process of a core decontamination stage for bleaching, and dirt molecules are broken through the strong oxidation effect of the two oxidants of the oxygen bleaching powder or the chlorine bleaching powder, so that the decolorizing effect is achieved.

3) Rinsing: after the linen is mainly washed, the linen generally passes through a middle-high speed dehydration process, the linen enters rinsing after dehydration, at the moment, water is poured to reach a high water level, the fabric fiber is kept in a swelling state, and meanwhile, the detergent and suspended dirt in the fabric are further diffused into the water by using the clean water through the mechanical force in the liquid cylinder. This process is repeated 3 to 4 times, each time the water temperature is gradually decreased in steps.

4) And (3) post-treatment: after the fabric is washed, the fabric can be chemically treated according to different purposes so as to meet the optimal use requirements of people on the fabric, including neutralization, softening, sizing and the like. Neutralizing: adding a proper amount of neutralizing acid agent from a feed inlet, keeping the water temperature at 30-40 ℃, and washing for 3-5 minutes at a medium/low water level. It is used for neutralizing alkalis, chlorine and calcium contained in the fabric lotion, recovering color brilliance and softness of the fabric, and protecting skin. Softening: adding a proper amount of softening agent from a feeding port, keeping the water temperature at 20 ℃, and washing for 5 minutes. The antistatic agent is used for enabling the textile fiber and the interior to be smooth and reach a good state, and the effects of softness, fluffiness and antistatic are achieved. Sizing: adding a proper amount of slurry from a feed inlet, wherein the requirements of water level, time and temperature are the same as those of neutralization. The sizing agent wets and permeates the fabric to form a layer of protective layer on the surface of the fabric, so that the surface of the fabric is stiff, the fiber is prevented from fluffing, and the service life of the fabric is prolonged.

5) And (3) dehydrating: and (4) carrying out high-speed dehydration to reduce the water content of the fabric as much as possible and accelerate the drying speed of the fabric. Generally 4-8 minutes, and the specific time is determined according to the moisture content of the fabric and the texture of the fabric.

In the mixed wastewater discharged by the five washing procedures, the main pollutants are anionic surfactant LAS in the synthetic detergent components, and the mixed wastewater also comprises sodium tripolyphosphate, a large amount of short fibers, a small amount of oil stains, a small amount of bacteria, coliform bacteria, viruses and other microorganisms in the synthetic detergent components. The wastewater has high water temperature, high content of suspended matters, turbid appearance, alkaline pH value of 8-11 and certain toxicity to animals and human bodies.

For the washing wastewater containing the anionic surfactant LAS, scholars at home and abroad discuss a series of treatment technologies, such as: amir Hossein Mahvi (2004) adopts chemical coagulation to remove anionic surfactant in detergent wastewater, lime, alum and ferric chloride are selected for experiments, and the experiments show that the ferric chloride treatment effect is the best, the COD removal rate is 89% and the LAS removal rate is 80%; the method has low treatment cost and simple operation, but the medicament has large demand and can generate a large amount of sludge and waste residues, and secondary pollution is easily caused by improper treatment. The Cuiyengsheng et al (2005) adopts a self-made electrochemical reactor to perform electrocatalytic oxidation treatment on the anionic surfactant wastewater, and the removal rate of the anionic surfactant reaches 96.02%; the method has simple equipment and good treatment effect, but the treatment power consumption is greatly influenced by the conductivity of the raw water and the energy consumption is extremely high. Tenmeizhen et al (2001) adopt a foam separation method as a pretreatment process, the COD removal rate is only 37%, and after the method is used in combination with an anaerobic-aerobic process, the COD removal rate is increased to 88.4%; the method has low energy consumption, low cost and simple operation, but is generally only suitable for the low-concentration LAS wastewater treatment. CN104086041A discloses a treatment system for surfactant wastewater: firstly discharging surfactant wastewater into an aeration regulating tank to regulate water quality and water quantity, then performing coagulating sedimentation, then sequentially performing treatment in a hydrolysis tank and a primary oxidation CBR tank, and performing Fenton oxidation and secondary oxidation contact tank treatment on the wastewater after sedimentation in an intermediate sedimentation tank; the defoaming device in the primary oxidation CBR pool has good treatment effect on surfactant wastewater with more foam, but the COD and LAS values of the effluent only reach the standard basically, and the treatment units are too many, so that the occupied area is too large. CN108101264A discloses a treatment system for surfactant wastewater: adding a precipitator/flocculant/chelating agent to carry out precipitation treatment on the surfactant wastewater, and then setting at least two-stage precipitation treatment and two-stage reverse osmosis treatment according to specific sites and water quality. The method has good effluent quality and can be used for recycling, but the pretreatment requirement of the reverse osmosis device is high, and the initial investment is large.

Disclosure of Invention

In order to solve the problems of the prior art, the invention aims to overcome the defects of the prior art, and provides a method and a device for treating surfactant wastewater aiming at the conditions that the prior art is difficult to be suitable for small and medium-sized washing enterprises and the treated water can be recycled.

In order to achieve the purpose, the invention adopts the following technical scheme:

a surfactant wastewater treatment process comprises the following steps:

a. draining the washing wastewater to be treated into a sump well through a drainage pipe network by gravity, removing large floaters, fluffs and other suspended matters in the washing wastewater to be treated through a basket filter and a rotary drum fine grid dirt separator, and conveying the washing wastewater to be treated to a transverse flow open type cooling tower through a lifting water pump for cooling;

b. b, automatically conveying the washing wastewater to be treated in the step a to a comprehensive regulating tank, and regulating the water quantity of the wastewater and balancing the water quality;

c. b, continuously lifting the wastewater treated in the step b into a hydrolysis acidification tank by using a submersible sewage pump, so that the wastewater flows into a biochemical tank to finish the degradation of organic matters; decomposing macromolecular organic matters into degradable micromolecular organic matters by utilizing the acidification and hydrolysis effects of various bacteria in the hydrolysis acidification pool, simultaneously mixing the wastewater with the mixed solution refluxed by the aerobic pool, and denitrifying the wastewater under the action of denitrifying bacteria;

d. c, enabling the wastewater treated in the step c to flow into an MBR membrane tank to complete solid-liquid separation until the effluent reaches the discharge and industrial water reuse standard; a small part of effluent reaching the standard is directly discharged outside, and most of the effluent is lifted to an activated carbon adsorption tank by a submersible sewage pump to be adsorbed, then flows into a full underground clean water tank to be stored, and is pumped to a roof recycling water tank by a multi-stage stainless steel pump to be recycled;

or, preferably, the wastewater treated in the step c flows into an MBR membrane tank to complete solid-liquid separation until the effluent reaches the discharge and industrial water reuse standard, and the effluent is directly and completely discharged;

e. and d, deoxidizing a part of the sludge discharged from the MBR membrane tank after the treatment of the step d by the deoxidizing tank, then refluxing the deoxidized part of the sludge to the hydrolysis acidification tank, discharging a part of the deoxidized sludge to the sludge storage tank, and finally carrying out filter pressing treatment and outward transportation.

Preferably, in the step a, the temperature of the raw water of the washing wastewater is 70-80 ℃, and the temperature of the wastewater is reduced to not higher than 35 ℃ through a cooling tower, so that the survival of the microorganisms for the subsequent biochemical treatment is ensured.

Preferably, in the step b, the regulating pool is divided into 2 grids, the regulating pool normally and simultaneously runs in parallel at ordinary times, a first grid area is used during cleaning and maintenance, and the other grid area stops working for maintenance and repair; a submersible stirrer and an air perforated aerator pipe are arranged in the tank, so that the sewage is completely mixed in the tank.

Preferably, in the step c, the hydrolysis acidification tank is provided with a soft biological filler, and the biochemical tank is provided with a disc type microporous aerator.

Preferably, in the step d, the MBR membrane tanks are divided into 2 grids, 2 groups of membrane modules are installed and run in parallel, and when one group of membrane tanks needs chemical cleaning, the other group of membrane tanks work normally; at least 20% of the effluent of the membrane pool is discharged, and no more than 80% of the effluent of the membrane pool is recycled after being treated by an activated carbon adsorption tank.

Preferably, in the step e, a submersible mixer is installed in the deoxidation tank, and dissolved oxygen is removed by mixing and stirring.

The invention relates to a surfactant wastewater treatment device, which implements the surfactant wastewater treatment method.

Compared with the prior art, the invention has the following obvious and prominent substantive characteristics and remarkable advantages:

1. the sewage in the production process is firstly collected in a water collecting well and sequentially passes through a basket filter, a rotary drum fine grid dirt separator, a transverse flow open cooling tower, a comprehensive adjusting tank, a hydrolysis acidification tank, an aerobic tank and an MBR membrane tank, and the effluent of the membrane tank can reach the discharge standard; continuously passes through the activated carbon adsorption tank, and the effluent can reach the reuse standard;

2. the invention has simple process, each step adopts the existing mature technology, and the operation is simple and convenient; the whole treatment system has few treatment units and small occupied area, and is suitable for small and medium-sized washing enterprises; the water outlet effect is good and can reach the recycling standard, and the cost can be greatly saved for the washing industry with high water consumption;

3. the invention aims at the surfactant wastewater, can increase and decrease the advanced treatment unit according to the actual engineering requirements, does not need reuse water in an actual enterprise, can save an activated carbon adsorption tower, can discharge the effluent of a membrane pool, and has good practicability.

Drawings

FIG. 1 is a flow chart of a conventional washing process.

FIG. 2 is a process diagram of surfactant wastewater treatment according to the present invention.

Detailed Description

The above-described scheme is further illustrated below with reference to specific embodiments, which are detailed below:

the first embodiment is as follows:

in this example, the washing wastewater generated from the washing process of bedsheets, towels, etc. in hotels and other units by a certain linen washing company is the target of wastewater to be treated, the wastewater yield of surfactant is 1500 tons/day, the COD of the inlet water is 600mg/L, and the available surface of the field is only (30+50) m × 6 m. The combined process of hydrolytic acidification, biochemical method, MBR and active carbon adsorption treatment is adopted. Referring to fig. 2, a surfactant wastewater treatment process includes the steps of:

In this embodiment, a whole set of sewage treatment facilities is built in the available site, the reuse water reaches reuse standard 'quality requirement for reuse water for laundry' DB11/471-2007, and CODcr is less than or equal to 60 mg/L. The method for treating the surfactant wastewater in the embodiment combines the characteristics of the treated surfactant wastewater, adopts a technical path of 'hydrolytic acidification + biochemical method', adopts a combined treatment method of 'MBR + activated carbon adsorption' for advanced treatment to treat the surfactant wastewater, and meets the treatment requirements of simplicity, high efficiency and economy.

Example two:

this embodiment is substantially the same as the first embodiment, and is characterized in that:

in this embodiment, a surfactant wastewater treatment process includes the following steps:

a. the step is the same as the first embodiment;

b. the step is the same as the first embodiment;

c. the step is the same as the first embodiment;

d. c, enabling the wastewater treated in the step c to flow into an MBR membrane tank to complete solid-liquid separation until the effluent reaches the discharge and industrial water reuse standard, and directly and completely discharging the effluent;

e. the procedure is the same as in the first embodiment.

According to the requirement that the waste water is not discharged for reuse in the enterprise waste water treatment, the method omits activated carbon adsorption tower equipment, has low cost, and leads the effluent to reach the quality standard of sewage discharge urban sewer CJ3082-1999, and the CODcr is less than or equal to 150 mg/L. The method for treating the surfactant wastewater in the embodiment combines the characteristics of the treated surfactant wastewater, adopts a technical path of 'hydrolytic acidification + biochemical method', adopts a combined treatment method of 'MBR + activated carbon adsorption' for advanced treatment to treat the surfactant wastewater, and meets the treatment requirements of simplicity, high efficiency and economy.

Example three:

this embodiment is substantially the same as the above embodiment, and is characterized in that:

in the embodiment, in the step a, the temperature of the raw water of the washing wastewater is 70-80 ℃, and the temperature of the wastewater is reduced to not higher than 35 ℃ through a cooling tower, so that the survival of the microorganisms in the subsequent biochemical treatment is ensured.

In this embodiment, in the step b, the regulating pool is divided into 2 compartments, and normally and simultaneously runs in parallel at ordinary times, a first compartment area is used during cleaning and maintenance, and another compartment area stops working for maintenance and repair; a submersible stirrer and an air perforated aerator pipe are arranged in the tank, so that the sewage is completely mixed in the tank.

In this embodiment, in the step c, the hydrolysis acidification tank is provided with a soft biological filler, and the biochemical tank is provided with a disc type microporous aerator.

In this embodiment, in the step d, the MBR membrane tanks are divided into 2 compartments, 2 groups of membrane modules are installed and run in parallel, and when one group of membrane tanks needs chemical cleaning, the other group of membrane tanks normally work; at least 20% of the effluent of the membrane pool is discharged, and no more than 80% of the effluent of the membrane pool is recycled after being treated by an activated carbon adsorption tank.

In this embodiment, in the step e, a submersible stirrer is installed in the deoxidation tank, and dissolved oxygen is removed by mixing and stirring.

In the embodiment, sewage in the production process is firstly collected in a water collecting well and sequentially passes through a basket filter, a rotary drum fine grid dirt separator, a transverse flow open cooling tower, a comprehensive adjusting tank, a hydrolysis acidification tank, an aerobic tank and an MBR membrane tank, and the effluent of the membrane tank can reach the discharge standard; continuously passes through the activated carbon adsorption tank, and the effluent can reach the reuse standard; the method has simple process, each step adopts the existing mature technology, and the operation is simple and convenient; the whole treatment system has few treatment units and small occupied area, and is suitable for small and medium-sized washing enterprises; the water outlet effect is good and can reach the recycling standard, and the cost can be greatly saved for the washing industry with high water consumption; this embodiment is directed against surfactant waste water, can carry out the adjustment of advanced treatment unit increase and decrease according to actual engineering demand, need not reuse water like actual enterprise, can save the active carbon adsorption tower, and the membrane pond goes out water and can arrange outward, and the practicality is good.

To sum up, in the surfactant wastewater combined treatment process of the above embodiment, the main technical path for treating wastewater is hydrolysis acidification and biochemical method, and the advanced treatment adopts MBR and activated carbon adsorption. The treatment system comprises a water collecting tank, a rotary drum fine grid, a cooling tower, an adjusting tank, a hydrolysis acidification tank, a biochemical tank, an MBR membrane tank, an activated carbon adsorption tower, a clean water tank, a deoxidation tank and a sludge storage tank. Wherein the water collecting tank, the rotary drum fine grid, the cooling tower, the regulating tank, the hydrolysis acidification tank, the biochemical tank and the MBR membrane tank are sequentially connected, and then the effluent of the membrane tank is discharged outside or flows into a clean water tank through an active carbon adsorption tower for recycling; and after passing through the deoxidation tank, part of the sludge in the membrane tank flows back to the hydrolysis acidification tank, and part of the sludge is discharged into the sludge storage tank for filter pressing and outward transportation. The surfactant wastewater combined treatment process provided by the embodiment is simple, occupies a small area, has a high COD removal rate, can reach the reuse standard of water quality, further saves the cost, is very suitable for medium and small linen washing enterprises to treat the surfactant wastewater, and has a good application prospect.

The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made according to the purpose of the invention, and any changes, modifications, substitutions, combinations or simplifications made according to the spirit and principle of the technical solution of the present invention should be replaced with equivalents as long as the object of the present invention is met, and the technical principle and the inventive concept of the present invention are not departed from the scope of the present invention.

Claims

1. a surfactant waste water treatment process, is characterized in that: comprise the steps:

a. The to-be-treated washing wastewater is gravity-drained into the water collection well through the drainage pipe network, and the large pieces of floating matter, fluff and other suspended solids in the to-be-treated washing wastewater are removed through the basket filter and the drum fine grid decontamination machine. , and then transport the to-be-treated washing wastewater to the cross-flow open cooling tower through the lifting water pump for cooling;

b. Self-flowing the to-be-treated washing wastewater treated in step a to a comprehensive regulating tank to adjust the amount of sewage and balance the water quality;

c. Utilize a submersible sewage pump to continuously lift the wastewater treated in step b into the hydrolysis and acidification tank, so that the wastewater flows into the biochemical tank to complete the degradation of organic matter; the wastewater is acidified and hydrolyzed by a variety of bacteria in the hydrolysis and acidification tank to remove macromolecular organic matter. It is decomposed into easily degradable small-molecule organic compounds, and at the same time, the wastewater is mixed with the mixed liquid returned from the aerobic tank, and the wastewater is denitrified by the action of denitrifying bacteria;

d. The wastewater treated in step c flows into the MBR membrane tank to complete the solid-liquid separation until the effluent reaches the discharge and industrial water reuse standards; a small part of the effluent that meets the standard is directly discharged, and most of the effluent is lifted by the submersible sewage pump to activated carbon adsorption After adsorption treatment in the tank, it flows into the fully underground clear water tank for storage, and is pumped to the roof water tank for reuse by multi-stage stainless steel pump;

Or, the wastewater treated in step c flows into the MBR membrane tank to complete the solid-liquid separation, until the effluent reaches the discharge and industrial water reuse standards, and the effluent is directly discharged;

e. After the treatment in step d, a part of the sludge discharged from the MBR membrane tank is deoxygenated by the deoxygenation tank and then returned to the hydrolysis and acidification tank, and part of the sludge is discharged into the sludge storage tank.

2. The method for treating surfactant waste water according to claim 1, wherein in the step a, the raw water temperature of the washing waste water is 70-80°C, and the temperature of the waste water is reduced to no higher than 35°C by the cooling tower. ℃, to ensure the survival of the subsequent biochemical treatment microorganisms.

3. The treatment method of surfactant waste water according to claim 1, it is characterized in that: in described step b, described regulation tank is divided into 2 grids, and usually runs in parallel at the same time normally, and the first grid area is used during cleaning and maintenance. , and another area to stop operations for maintenance; install a submersible agitator and an air perforated aeration pipe in the pool, so that the sewage can be completely mixed in the pool.

4. The method for treating surfactant wastewater according to claim 1, characterized in that: in the step c, a soft biological filler is provided in the hydrolysis and acidification tank, and a disc-type microporous aeration is provided in the biochemical tank device.

5. the treatment method of surfactant waste water according to claim 1, is characterized in that: in described step d, described MBR membrane pool is divided into 2 grids, installs 2 groups of membrane modules, runs in parallel, one group of membrane pools When chemical cleaning is required, the other membrane pools work normally; at least 20% of the total volume of the effluent from the membrane pool is discharged, and no more than 80% of the total volume is treated by activated carbon adsorption tanks for reuse.

6 . The method for treating surfactant wastewater according to claim 1 , wherein in the step e, a submersible mixer is installed in the deoxygenation tank to remove dissolved oxygen by mixing and stirring. 7 .

7 . A device for treating surfactant wastewater, characterized in that: implementing the method for treating surfactant wastewater according to claim 1 .