1 Project Overview
PU leather is a product of rapid development in recent years, it is a wide range of beautiful and inexpensive, widely used in the automobile, shoes and leather, bags, sofas, decorative and apparel production industry, is a good substitute for leather, and leather-based cloth is the basis of the material of the PU leather, the market demand is great! A county county existing weaving factory more than 20, more than 1,500 looms, the annual output of leather-based cloth 90 million meters, in the past a county county weaving factory production of leather-based blank cloth without bleaching and dyeing processed directly sold to the field, the product added value is low. Fujian Province, so-and-so printing and dyeing limited company in a county of Putou Industrial Zone, the construction of the annual output of PU leather-based cloth 30 million meters of this project, can become a county of the local bleaching and dyeing base, can increase the county of a county of county tax revenues, but also to solve some of the remaining labor force.
Textile printing and dyeing industry is a large industrial wastewater discharge, according to estimates, the national daily discharge of wastewater amount of about (3-4) × 106m3, and wastewater in the high concentration of organic matter, complex composition, deep chromaticity, pH changes, water quality and water quality changes, is more difficult to deal with industrial wastewater. According to the data provided by Fujian Province so-and-so printing and dyeing Co., Ltd, the project was completed and discharged 800 tons of wastewater / day.
According to "Construction Project Management Regulations" and "Environmental Protection Law", the construction of environmental protection facilities should be with the main project "three simultaneous". Ltd. commissioned by the Fujian Province, we put forward the project's wastewater treatment program, according to the construction of this program can ensure that the wastewater discharge standards, can greatly reduce the project's discharge of wastewater on the adverse effects of a county.
2 program design basis
2.1 Fujian Province, so-and-so printing and dyeing Co., Ltd. to provide water quality parameters
2.2 "textile dyeing and finishing industry water pollutant discharge standards" GB4287-92
2.3 "outdoor drainage design specification" GBJ14-87
2.4 "building drainage design specification GBJ15-87
2.5 "Regulations on Environmental Protection of Fujian Province"
2.6 Monitoring data of completion acceptance of wastewater treatment facilities of other similar enterprises
3 Program Design Principles
3.1 Feasibility principle. In the engineering design, while ensuring the feasibility of the process, taking into account the ability to economically license (total investment costs, low operating costs, etc.), consider the feasibility of the process and economic feasibility of coordination and unity.
3.2 Reliability principle. Through the research on the current wastewater treatment in the printing and dyeing industry, combined with many years of experience in wastewater treatment, while drawing on the current successful cases of printing and dyeing wastewater treatment, and with the integration of current advanced wastewater treatment equipment, to develop a reasonable, mature and reliable wastewater treatment process, to ensure that the wastewater treatment system can be a long term, stable and reliable operation.
3.3 The principle of advancement, the use of current advanced processes and equipment for wastewater treatment.
3.4 Convenient operation and management, simple and practical technology, improve operation and management level, and realize scientific and modern management.
3.5 Avoid secondary pollution, while treating wastewater, avoid secondary pollution from sludge and noise.
4 Wastewater quality and quantity
Fujian province so-and-so printing and dyeing Co., Ltd. uses raw materials for cotton or polyester-cotton blank fabrics, dyes with direct and disperse dyes, additives such as caustic soda, sodium carbonate, hydrogen peroxide, surfactants, industrial salt, linting agent and so on.
Wastewater is discharged continuously, but the water quantity and quality change greatly without fixed pattern. According to the information provided by Fujian Province So-and-so Printing and Dyeing Company Limited and combined with the information of the same type of enterprises, the wastewater quality parameters are as follows:
Wastewater Quantity 800 tons/day
CODcr 1767mg/l
BOD5 868mg/l
SS 121mg/l
H 9~12
NH3-N 15.1mg/l
S2- 2.3mg/l
Color 1000 times
5 Wastewater Emission Standards after Treatment
According to the "Textile Dyeing and Finishing Industry Water Pollutants Emission Standards" GB4287-92, the following is stipulated:< /p>
CODcr 100mg/l
BOD5 25mg/l
Color 40 times (dilution times)
H 6~9
SS 70mg/l
Ammonia 15mg/l
Sulphide 1.0mg/l
Hexavalent chromium 0.5mg/l <
Copper 0.5mg/l
Aniline 1.0mg/l
Chlorine dioxide 0.5mg/l
Maximum permissible water discharge 2.5m3/hundred meters of cloth (width 914mm)
6 Wastewater treatment process
6.1 Characteristics of wastewater from textile dyeing and finishing industry
Textile dyeing and finishing industry's Wastewater mainly comes from desizing, boiling, bleaching, dyeing and finishing sections, the characteristics of wastewater in each section are as follows:
6.1.1 Desizing Wastewater
Desizing is the use of chemicals to remove impurities on the textile and slurry, to facilitate the processing of the next process, the wastewater contained in this part of the impurity fibers are more. In the past, due to the textile factory with starch as raw material, so the wastewater BOD5 concentration is very high, is the whole printing and dyeing wastewater in the main source of BOD5, so that the wastewater B/C is relatively high, often greater than 0.3, suitable for biochemistry, but with the progress of science and technology, the pulp used in printing and dyeing factories are gradually replaced by CAM/PVA, so that the wastewater in the decline of BOD5, CODcr rises, the wastewater biochemistry is reduced.
6.1.2 Boiling and refining
Boiling and refining process is to remove impurities such as wax, pectin, grease and oil contained in fabrics, the chemicals used are mainly caustic soda and surfactants, this part of the wastewater is large, alkaline, CODcr, BOD5 is high, and it is the main source of organic pollution in printing and dyeing wastewater.
6.1.3 Bleaching wastewater
Bleaching is mainly using oxygen atoms to oxidize the coloring groups in the fabric to achieve the purpose of whitening the fabric, bleaching wastewater is generally low in organic content, and the bleach used is mostly hydrogen peroxide.
6.1.4 Dyeing wastewater
The dyeing process is the mainstay of the project, in which direct and disperse dyestuffs and various auxiliaries are used, thus making the dyeing process a complex process, and making the quality of the dyeing wastewater show complexity and diversity. Generally speaking, dyeing wastewater is highly alkaline, dark in color, irritating to human organs, with high concentration of BOD5 and CODcr. Various dyes, surfactants and various auxiliaries contained in the wastewater are the largest source of organic matter pollution in printing and dyeing wastewater.
6.2 Current status of printing and dyeing wastewater treatment
The treatment of printing and dyeing wastewater is based on biochemical method, and often in series with physical and chemical methods, in order to achieve better results, and the current common treatment methods for printing and dyeing wastewater treatment are:
6.2.1 Completely mixed active pollution method
This method is a more mature process, and there is a certain degree of printing and dyeing wastewater treatment history, currently applied to most factories in the textile system. A city printing and dyeing plant wastewater treatment that is used in this method. The main facilities of this method are conditioning tank, aeration tank and sedimentation tank.
Regulation pool is mainly used to regulate the water quality and quantity of wastewater discharged from various sources of pollution, to prevent the formation of the aeration pool impact, to avoid bacterial death. Therefore, the longer the wastewater stays in the regulating tank, the better, but also consider the construction costs, so generally according to the production cycle of the enterprise and the conditions of the area to design the regulating tank.
The main role of the aeration tank is to oxygenate the mud-water mixture to ensure that the activated sludge in the decomposition of organic matter when the amount of oxygen required, while the activated sludge and wastewater fully mixed. General technical requirements of the aeration tank is often sludge load 0.3-0.4kgBOD5/kg.MLSS.d aeration time of about 4-6 hours, sludge concentration is generally in the 3-4g/l, but with the increasing proportion of chemical fiber fabrics and water treatment technology, these technical requirements have changed.
Sedimentation tank is mainly to make mud and water separation, and further degradation of organic matter in the sedimentation, after mud and water separation of water discharged directly, a part of the sludge back into the aeration tank, a part of the residual sludge for discharge.
Activated sludge method is characterized by sewage and biological sludge contact is more uniform and durable, pool water concentration distribution is more uniform, the water temperature control range is wider, the operation of the water in the cloth is also relatively simple, the treatment efficiency is higher, the general BOD5 removal rate of up to 95% or more, the CODcr removal rate of about 60%. However, the method is more complex management, easy to sludge expansion and upturn, and covers a large area.
6.2.2 Contact oxidation
Contact oxidation is a wastewater treatment technology that has been gradually and widely used in recent years. Most of the knitting and dyeing factories in the Shanghai textile system use a tower filter (a type of contact oxidation method). Tower filter structure is the tower plus packing, the role of the tower is oxygenated and placed packing, the height of the tower is based on the oxygenation requirements and sewage and packing on the biofilm contact time to design, generally need 2.5-4 hours, volumetric loading in 2-3kgBOD5/m3, packing in the past the use of surface roughness of the solids so that the biofilm can attach to it, with the development of the plastics industry, the current use of cellular packing and soft packing as a biofilm support. With the development of the plastic industry, the current use of honeycomb packing and soft packing for biofilm support, to achieve better results.
Tower filter is characterized by easy operation and management, short treatment time, small footprint, but the organic matter removal rate is relatively low this, general CODcr removal rate of 45-60%, BOD5 removal rate of 70-90%, chromaticity removal rate of 30-50%.
6.2.3 Physicochemical method
With the increase of chemical fiber components in the fabric and the use of chemical additives slurry, printing and dyeing wastewater in the BOD5 and CODcr ratio has changed, the biochemistry of wastewater deterioration, in order to achieve a better treatment, the textile industry began to use the physicochemical method (ozone coagulation and precipitation and flotation, etc.) to deal with printing and dyeing wastewater. Physicochemical method commonly used coagulants are aluminum sulfate, ferrous sulfate, ferric chloride, alkaline aluminum chloride, polymer coagulants and so on. General physical-chemical method for secondary treatment, there are some factories such as the second Shanghai Silk Dyeing and Printing single physical-chemical method of treatment of printing and dyeing wastewater. Practice has proved that coagulation air flotation is a more suitable physical and chemical treatment methods, because printing and dyeing wastewater contains a large number of pollutants such as cellulose, slurry, etc., was suspended and colloidal state, and some dyes such as dispersed, sulfurized, reducing dyes and paints and coagulants, especially aluminum coagulants produce flocs with small specific gravity, suitable for the use of air flotation method of treatment.
Other chemical methods, such as ozone as an oxidant decolorization effect is very good, but power consumption, high treatment costs, not easy to promote. Similarly, the electrolysis method also exists in large power consumption, large amount of steel, and the operation and management of more complex problems.
6. 2.4 A/O method
(1) There is A1/O method, that is, anoxic/aerobic biological denitrification process, is the abbreviation of the English Anoxic/Oxic, its main function is to remove the organic matter and denitrification, the total removal rate of BOD5 and SS is generally 90-95%, and the total nitrogen removal rate is more than 70%.
(2) there is A2 / O method, that is, anaerobic - aerobic phosphorus removal process, is the abbreviation of the English Anaerobic-Oxic, its main function is to remove organic matter and phosphorus removal, generally for BOD5 and SS and removal rate of 95%, phosphorus removal rate of more than 70%.
(3) A2 / O method, that is, anaerobic - anoxic - aerobic biological denitrification and phosphorus removal process, is the abbreviation of the English Anaerobic-Anoxic-Oxic, whose function is to remove organic matter and phosphorus denitrification.
6.2.4 Other methods
There are A/B method, hydrolysis - aerobic biological treatment process, etc., is a newer treatment process, but also applied to printing and dyeing wastewater treatment, this article will not repeat.
6.3 The treatment process of printing and dyeing wastewater used in this program
6.3.1 Process flow:
After a comprehensive comparative analysis, and combined with many years of experience in the treatment of printing and dyeing wastewater to the principle of economy and feasibility, it was decided to adopt the following treatment process:
.3.2 Brief description of the process flow
The concentrated alkaline wastewater is first treated through the grating After treatment, it is used for dust removal by water film dust collector. After smoke and dust removal, it can reduce PH value so that the system doesn't need to add acid to adjust PH, and it can remove about 30% of CODcr, so that the load of biochemical system can be reduced in order to save the operation cost and ensure the PH condition of biochemical treatment. Dust water precipitation and other production wastewater and by coarse and fine grating to remove coarse impurities, into the regulating pool, set up in the regulating pool pre-aeration system, can be uniform water quality and to prevent impurities from precipitation, but also can be adjusted to the amount of water and to a certain extent, to remove the sulfide in the wastewater. The water in the regulating tank is lifted to the reaction tank by pump, and then flows into the vertical flow sedimentation tank for mud-water separation by gravity after dosing reaction. The sludge at the bottom is discharged to the sludge thickening tank. The vertical flow sedimentation tank can remove part of the organic matter and greatly reduce the sulfide and CODcr, chromaticity, reduce the PH value and improve the B/C ratio, creating conditions for subsequent biochemical treatment.
The supernatant of vertical flow sedimentation tank flows into hydrolysis and acidification tank by gravity, and at the same time, it adjusts nutrients (P), degrades macromolecule material, further improves B/C, and reduces CODcr. The effluent of hydrolysis and acidification tank flows to A/O contact oxidation tank by gravity. In the A/O contact oxidation tank to remove most of the dissolved organic matter and denitrification denitrification, O pool end of the mixture back to the beginning of the A pool, of which the A pool accounted for 1/3, the O pool accounted for 2/3, back to the flow rate of 2 times the amount of treated water.
The effluent from the A/O contact oxidation pool flows by gravity to the air flotation system, after dosing air flotation, the floating sludge to the sludge thickening tank, and the effluent to the discharge tank, and when necessary, the decolorant is added to the discharge tank, and the wastewater meets the standard is discharged nearby.
The remaining activated sludge is discharged into the sludge dewatering tank, and the supernatant of the sludge dewatering tank is recycled into the regulating tank. Dewatering of dry sludge properly handled (can be mixed with coal sent to the boiler incineration), to prevent secondary pollution.
6.3.3 Description of the main treatment unit
(1) hydrolysis acidification
In anoxic conditions, the organic matter in the wastewater to complete the first stage of anaerobic reaction, the decomposition of some of the difficult to biodegradable organic matter into small molecules of organic matter that are readily biodegradable, to reduce the CODcr, BOD5, SS, S2-, chromaticity, and to improve the biochemical properties of the wastewater to create good conditions for the subsequent biochemical treatment. biochemical treatment to create good conditions.
(2)Flocculant
The wastewater is alkaline and contains sulfide. Commonly used flocculants are PAC or PFS, and coagulant aid is PAM, but too much PAC may affect the subsequent biochemical treatment, so this process selects FM compound flocculant.FM has significant effect on the removal of chromaticity and CODcr of dyeing wastewater, and it has the performance of desulfurization. The research for the Shanghai Municipal Science and Technology Commission's research projects, has been organized by the Shanghai Municipal Science and Technology Commission identification, and practical application.FM flocculant price is low, the source is convenient, can be compounded on the spot. Of course, other suitable flocculants can also be used, coagulant aid for PAM.
(3) Biochemical treatment
Biological contact oxidation is a newer biofilm method, is installed in the pool filler, filler has a large specific surface area, is a biological carrier, generating a larger concentration of activated sludge in order to increase the volumetric load of the contact oxidation pool to improve the removal of pollutant efficiency. At the same time, it has the characteristics of simple equipment, small area, convenient maintenance, flexible operation and low operation cost. It has been widely used in chemical, food, pharmaceutical, printing and dyeing and other industries of wastewater treatment, the effect is remarkable. It is recommended by the State Environmental Protection Bureau as the best practical technology for environmental protection.
6.3.4 Characteristics of wastewater treatment process
(1) Concentrated alkali wastewater after fumigation and dust removal can reduce the PH value, so that the system does not have to add acid to adjust the PH, and can remove about 30% of the CODcr, so that the load of the biochemical system is reduced in order to save the recurrent costs, to ensure that the biochemical treatment of the PH conditions.
(2) dosing reaction precipitation, the main purpose is to remove part of the organic matter and greatly reduce sulfide, reduce the chromaticity and SS, improve the B/C ratio, and appropriately reduce the PH value (PH<10), to create conditions for biochemical.
(3) Hydrolysis acidification pool using filler form, timed aeration flushing biofilm to prevent precipitation. Every four hours open 10 minutes, can make the pool basically maintain anaerobic state, but also to achieve the purpose of membrane replacement.
(4) The A/O system adopts contact oxidation, which can reduce structures, save investment, impact resistance, low sludge, mainly removing most of the dissolved organic matter and denitrification denitrogenation.
(5) The final dosing reaction air flotation system can further remove non-degradable organic matter, color, etc. so that the treated water meets the discharge standards.
(6) The discharge pool is mainly set up to facilitate the monitoring, when necessary, can also be added to the decolorant.
7 main structures, equipment and other investment estimates (ultimately based on the expansion of the initial design)
7.1 main structures design parameters
No. Name Parameters Material Quantity Remarks
1 catchment wells 10m3 brick mix 1
2 regulating pre-exposure pool 450m3 brick mix 1 can be increased or decreased according to the site conditions
3 Sedimentation tank 80 m3 steel concrete 1 can be increased or decreased according to the site conditions
4 Hydrolysis acidification tank 450m3 steel concrete 1
5 Contact oxidation tank 700m3 steel concrete 1
6 Coagulation air flotation (including the reaction tank) 40m3 brick mix 1
7 Machine pump room 40m2 brick mix 1
8 Sludge drying tank 30m2 brick mix 3
7 Sludge pump room 40m2 brick mix 1
8 Sludge drying tank 30m2 brick mix 1
8 Sludge drying tank 30m2 brick mix 1
9 Sludge drying tank 30m2 brick mix 3 seat can be increased or decreased according to the site conditions
9 Sludge thickening tank 60 m3 brick mix 1 seat
10 Discharge tank 35 m3 brick mix 1 seat
7.2 Main equipment and investment
Serial No. Name Specification, model Quantity Price (million yuan)
1 Coarse and fine grating Non-standard 2 sets 0.2
2 Sewage pump Q=40,H=10 1 set 0.4
2 Sewage pump Q=40,H=10 1 set 0.4
2 Sewage pump Q=40,H=10 1 set 0.4 10 1 0.4
3 Aerator Q=10,H=5 3 13.6
4 Mixer 1 1.8
5 Packing TB/TA2-TH1 800 m3 15
6 Microporous aeration TK/R65 500 5.3
7 Sewage pump Q=70,H=10 1 0.3
7 Sewage pump Q=70,H=10 1 0.3 10 1 set 0.3
8 Dosing equipment non-standard (anti-corrosion) 0.8
9 Partially pressurized dissolved air flotation machine non-standard 6.8
10 Automatic control cabinet non-standard 1 set 0.85
11 Aeration system non-standard 3.2
12 Pre-aeration system non-standard 1.6
13 Cable line lighting instrumentation 0.6
14 Fillers non-standard 3.2
12 Pre-aeration system non-standard 1.6
13 Cable line lighting instrumentation 0.6
13 Cable line lighting instrumentation 0.6
14 Packing support 1.3
15 Pipeline valves 2.7
16 Installation fee (factory installation) 0
17 Transportation fee 0.8
18 Subtotal 55.25
7.3 Other costs
Serial No. Name Amount
1 Design fee 3.0
2 Commissioning fee (excluding cost of chemicals) 1.6
3 Subtotal 4.6
Total investment cost (excluding civil construction and air-floating canopies 598,600 yuan (total drainage metering flow meter is not taken into account), the cost of civil construction of about 750,000 yuan, the detailed cost should be finalized after the completion of the preliminary design.
8 Wastewater treatment costs
8.1 operation and management personnel wages:
Wastewater treatment station 24 hours a day continuous three shifts of three runs, the operator of each shift 1 person, *** counting 3 people. According to the average monthly salary of 500 yuan 3 × 12 × 500 yuan / 1658/365 = 0.03 yuan / ton - water
8.2 Pharmacy fees: coagulant FM and coagulant aid PAM combined use, 0.26 yuan / ton - water.
8.3 Electricity: 0.33 yuan / ton - water.
8.4 Total running cost per ton of water treated:
0.03+0.26+0.33=0.62 yuan
Regular running cost: 0.62 yuan/ton - water.
9. Supplementary Notes Due to the time rush and failure to conduct on-site investigation, the final program may also need to be adjusted appropriately.