To remove the Hydrogen (H2) gas this is released from EC process due to reaction.
To increase flock size to bigger
STRENGTH OF HYDROCHLORIC ACID
BURETTE
0.1 N Sodium hydroxide solution
SAMPLE PREPARATION
Take 10 gm of HCl in standard flask and make up to 500 ml using neutral water
CONICAL FLASK
10ml of above diluted sample
2-3drops Phenolphthalein indicator
TITRATION
0.1N Sodium hydroxide Vs Dilute hydrochloric acid
ENDPOINT
Appearance of pink color
CALCULATION
Strength of Hydrochloric acid = Titrate value x 0.1 x 36.47 x500 x 100
Weight of HCL x 10 x 1000
= Titrate value x 1.82 %
STRENGTH OF SODIUM HYDROXIDE
BURETTE
0.1 N Hydrochloric acid.
SAMPLE PREPARATION
Take 2 gm of caustic dissolved In 250 ml distilled water
CONICAL FLASK
25 ml of above diluted sample
2-3drops Phenolphthalein indicator
The solution turns pink
TITRATION
0.1N Hydrochloric acid Vs Dilute sodium hydroxide
ENDPOINT
Disappearance of pink color
CALCULATION
Strength of Sodium hydroxide = Titrate value x 0.1 x 40 x 250 x 100
Weight of NaoH x 25 x 1000
= (Titrate value x 0.1 x 40) / 2
= (Titrate value x 4) / 2
= Titrate value x 2
STRENGTH OF SODIUM CARBONATE
BURETTE
0.1 N Hydrochloric acid.
SAMPLE PREPARATION
Take 2 gm of Soda ash dissolved In 250 ml distilled water
CONICAL FLASK
5 ml of above diluted sample
2-3 drops Methyl Orange indicator
The solution turns Golden yellow
TITRATION
0.1N hydrochloric acid Vs Dilute sodium carbonate
ENDPOINT
Appearance of Red Orange color
CALCULATION
Strength of Sodium carbonate = Titrate value x 0.1 x 53 x 250 x 100
Weight of Na2CO3 x 25 x 1000
= (Titrate value x 0.1 x 53) / 2
= (Titrate value x5.3) / 2
= Titrate value x 2.65
STRENGTH OF ACETIC ACID
BURETTE
0.1 N Sodium Hydroxide
SAMPLE PREPARATION
Take 2 gm of Acetic acid dissolved In 250 ml distilled water
CONICAL FLASK
25 ml of above diluted sample
2-3 drops Phenolphthalein indicator
No color change
TITRATION
0.1N Sodium hydroxide Vs Dilute acetic acid
ENDPOINT
Appearance of pink color
CALCULATION
Strength of Acetic acid = Titrate value x 0.1 x 60 x 250 x 100
Weight of CH3COOHx 25 x 1000
= (Titrate value x 0.1 x 60) / 2
= (Titrate value x 6) / 2
= Titrate value x 3
STRENGTH OF SULFURIC ACID
BURETTE
0.1 N Sodium hydroxide
SAMPLE PREPARATION
Take 2 gm of Sulfuric acid dissolved In 250 ml distilled water
CONICAL FLASK
25 ml of above diluted sample
2-3 drops Phenolphthalein indicator
No color change
TITRATION
0.1N Sodium hydroxide Vs Dilute sulfuric acid
ENDPOINT
Appearance of pink color
CALCULATION
Strength of Sulfuric acid = Titrate value x 0.1 x 49 x 250 x 100
Weight of H2SO4 x 25 x 1000
= (Titrate value x 0.1 x 49 / 2
= (Titrate value x 4.9) / 2
= Titrate value x 2.45
STRENGTH OF HYDROGEN PEROXIDE
BURETTE
0.1 N Potassium permanganate
SAMPLE PREPARATION
Take 5 gm of H2O2 dissolved In 250 ml distilled water
CONICAL FLASK
25 ml of above diluted sample
20 ml of 2N Sulfuric acid
30 ml of distilled water
TITRATION
0.1 N Potassium permanganate Vs Dilute hydrogen peroxide
ENDPOINT
Appearance of pink color
CALCULATION
Strength of Hydrogen peroxide = Titrate value x 0.1 x 17x 250 x 100
Weight of H2O2 x 25 x 1000
= (Titrate value x 0.1 x 17)/ 5
= (Titrate value x 1.7) / 5
= Titrate value x 0.34
STRENGTH OF SODIUM BI SULFITE
SAMPLE PREPARATION
Take 2gm of sodium bi sulfite dissolved In 250 ml distilled water
TITRATION
S.NO
BLANK
SAMPLE
Burette
0.1 N Sodium thio sulfate
0.1 N Sodium thio sulfate
Conical flask
25 ml distilled water + 50 ml iodine solution
25 ml diluted sample + 50 ml iodine solution
Titration
Titrate up to the appearance of light yellow
Titrate up to the appearance of light yellow
Indicator
Add starch- blue color appears
Add starch- blue color appears
Titration
Continue with 0.1 N Sodium thio sulfate
Continue with 0.1 N Sodium thio sulfate
End point
Disappearance of blue color
Disappearance of blue color
Titration value
A
B
CALCULATION
Strength of Sodium bi sulfite = 5.205 X (A – B)
2
= 2.602 X (A – B)
STRENGTH OF SODIUM SULFATE
SAMPLE PREPARATION
Take 8gm of sodium sulfate dissolved In 250 ml distilled water
ROCEDURE
In a clean 250 ml beaker 25 ml of diluted sample and 5 ml of Hydrochloric acid is added and
mix properly. Then 25 ml of 10% Barium chloride solution is added with stirring . The solution is boiled with 50 ml of distilled water for 15 min and kept for at least 6 hours. The precipitate is filtered through a gooch crucible and washed with hot distilled water for several times to remove chlorides and dried to constant weight at 105^C.
CALCULATION
Strength of Sodium sulfate = (608.6 X Wt. of the precipitate) / 8
STRENGTH OF SODIUM SILICATE
BURETTE
0.1 N Hydrochloric acid
SAMPLE PREPARAT
Take 2gm of sodium silicate dissolved In 250 ml distilled water
CONICAL FLASK
25 ml of above diluted sample
2-3 drops of Methyl orange indicator
TITRATION
0.1 N Hydrochloric acid Vs Dilute sodium silicate
ENDPOINT
Appearance of red orange
Then the solution in the conical flask is treated with 5 ml of concentrated Hydrochloric acid and is evaporated to dryness.
The residue is again treated with 5 ml of concentrated Hydrochloric acid and once again evaporated to dryness.
This residue is filtered through a What Mann No .40 filter paper and washed with hot distilled water for several times to remove soluble impurities.
Then the filter paper is ignited in a weighed silica crucible . After ignited
STRENGTH OF SODIUM SULFIDE
SAMPLE PREPARATION
Take 2gm of sodium sulfide dissolved In 250 ml distilled water
SAMPLE -A
In a 250 ml beaker 25 ml of diluted sample and 25 ml of 20 % Zinc sulfate solution are taken. The mix is stirred well. The precipitate is filtered through a filter paper and the filtrate is collected in a conical flask. The precipitate is washed with water and the washings are also added to the conical flask.
TITRATION
S.NO
SAMPLE
SAMPLE – A
Burette
0.1 N Iodine solution
0.1 N Iodine solution
Conical flask
25 ml diluted sample
Sample – A
Titration
Titrate up to the appearance of light yellow
Titrate up to the appearance of light yellow
Indicator
Add starch- blue color appears
Add starch- blue color appears
Titration
Continue with 0.1 N Iodine solution
Continue with 0.1 N Iodine solution
End point
Disappearance of blue color
Disappearance of blue color
Titration value
A
B
CALCULATION
Strength of Sodium bi sulfite = (3.903 X (A – B))/2
STRENGTH OF SODIUM ACETATE
BURETTE
0.1 N Hydrochloric acid.
SAMPLE PREPARATION
Take 5gm of Sodium acetate
CONICAL FLASK
25 ml of above diluted sample
3 drops Methyl Orange indicator
The solution turns Golden yellow
TITRATION
0.1N Hydrochloric acid Vs Dilute sodium acetate
ENDPOINT
Appearance of Red Orange color
CALCULATION
Strength of Sodium acetate = Titrate value x 0.1 x 136x 250 x 100
Weight of CH3COONa.3H2O x 25 x 1000
= (Titrate value x 0.1 x 136) / 5
= (Titrate value x13.6) / 5
= Titrate value x 2.72
STRENGTH OF ALUMINIUM SULFATE
SAMPLE PREPARATION
Take 10gm of sodium sulfate dissolved In 250 ml distilled water
PROCEDURE
In a clean 500 ml beaker 25 ml of diluted sample and 50 ml of 10 % Ammonium chloride solution, 150 ml of distilled water and 2 drops of methyl red indicator solution are added. The solution is heated just to boiling and 10% ammonium liquor solution is added till the color changed to distinct yellow. After again boiling for 2 min, the precipitate of aluminium
hydroxide is filtered when hot , washed with hot ammonium nitrate solution and ignited in a muffle furnace to constant weight in a porcelain crucible . the ash is cooled in a desiccators and weighed.
CALCULATION
Strength of aluminum sulfate = (6537 X Wt. of the Ash) / 10
STRENGTH OF SODIUM NITRITE
BURETTE
0.1 N Potassium permanganate
SAMPLE PREPARATION
Take 2 gm of NaNO2 dissolved In 250 ml distilled water
CONICAL FLASK
25 ml of above diluted sample
20 ml of 2N Sulfuric acid
Heat up to 60 ^ C
TITRATION
0.1 N Potassium permanganate Vs Dilute sodium nitrite
ENDPOINT
Appearance of pink color
CALCULATION
Strength of sodium nitrite = Titrate value x 0.1 x 34.51x 250 x 100
Bar screen and screening water treatment is the first process unit operation used at wastewater treatment plants. Screening removes objects such as rags, paper, plastics and metals to prevent damage and clogging of downstream equipment and piping.Cleaning frequency depends on the characteristics of the wastewater entering a plant.
Bar Screen Operation and maintenance considerations
Check and clean the bar screen at frequent intervals.
Do not allow solids to overflow /escape from the screen bar screen
Ensure no large gaps are formed due to the breakage of the screening water treatment.
Replace breakage bar screen immediately.
Mechanically cleaned screening system to remove larger materials because they reduce labor cost and they improve flow conditions and screening capture.
Mechanically cleaned bar screen should have a standby screen to put in operation when the primary screening device is out of service.
Trouble Shooting of screening water treatment
S.NO
PROBLEM
CAUSE
1
Large particles pass through and check the pumps
Poor operation /screen damaged
2
Up stream water levels is much higher than down stream level
Poor operation (inadequate cleaning)
3
Excessive collection of trash on screening water treatment
Poor operation
4
Excessive odor
Poor operation /trash disposal practices.
Daily and weekly maintenance work
Check gear box oil qty periodically and completely drain out oil and replace afresh as per manufacture’s recommendation.
Check oil pump every day ,top up if necessary
Check every day chain alignments and must periodically 4 hrs once chain cleaned or removed impurities materials.
Main use of screening water treatment
To remove the suspended solids
To avoided the pump cloaking
To increase the Bacteria attachment in the FBBR system
To avoided the solids cloaking in the air distribution system in Equalization tank
To increase the air volume in Equalization tank
Project Brief of screening water treatment plant
Auto is engaged into printing of textile garments using pigments and reactive colours. The Effluent Treatment Plant is designed to treat 40m3 per day of the effluent to achieve the norms prescribed by the local governing bodies and BSR guidelines. The Factory presently produce only up to 10m3/Day Effluent. The ETP is designed for higher capacity considering the future expansion and addition of Washing Process.
Plan Capacity of screening water treatment plant
The Effluent screening water treatment Plant is designed to treat wastewater generated from the processing unit. The Effluent treatment plant is designed to treat 40m3/day of Washing & Printing combined effluent generated from the process house (Washing 15m3/Day & Printing 5m3/Day). The plant will be capable of operating at the flow rate of 2m3/hr. The Present Effluent generation is 10m3/Day and the Plant is operated for 10-12 Hours per Day with 50% flow rate.
Conclusion
The treatment plant is based on Electro-coagulation Treatment. Electrocoagulation system has distinct advantages for the treatment of Textiles industrial wastewater. EC Systems present high efficiency, easy operation and environmental compatibility this process involves generation of coagulants by electrolytic oxidation of a sacrificial anode (iron) by applying a direct current. The most widely used electrode materials in electrocoagulation process are iron. The hydrolyzed iron ions can form long chains of Fe-O-Fe-OH which may chemically adsorb a large amount of contaminants. Screening water treatment with bar screen is very essential for etp.
Secondary clarifier design tank is used in ETP. We use water for many activities, most of which contaminate the water in some Way, i.e. By using detergents, chemicals, dyes t in fabric and yarn in industrial process. This contaminated water is called waste water. Water after usage is called waste water or effluent.
Main use of Secondary Clarifier
To Recirculation the Bacteria to the FBBR system
To reduce the suspended solids in the effluent
To avoided the Bacteria escape to other system
To remove the odor in the effluent in secondary clarifier design tank
To reduce the current and electrode consumption in EC system
To increase the efficiency of FBBR system
Wastewater composition
Wastewater contains approximately 99.0% water and 1% solids maximum.
Expressed in another way, every 1000L of wastewater contains about 10kg of
Solids. The solids are organic and inorganic compounds and are suspended in the
Waste water. Volatile solids are about 70% of the wastewater solids and give the
Water its unpleasant characteristics.
The majority of the solids – carbohydrates, fats and proteins – are broken down
During treatment into more stable inorganic compounds by bacteria and other
Micro-organisms.
Wastewater also contains some compounds that are resistant to normal treatment
Processes, including:
Organics
Fats, oils, grease & organic chemicals
Inorganics
Chlorides, heavy metals, nitrogen, phosphorus and sulphur.
Gases
Hydrogen (H2), sulphide (SO2), methane (CH4) and carbon-di-oxide (CO2).
Effluent treatment plant (etp) capacity
The Effluent treatment plant is designed to treat 2000m3 of Textile dyeing combined
Effluent generated from the process house. The plant will be capable of operating at the flow rate of 100m3/hr. The operating cycle of the plant shall be 20 hours.
Raw effluent characteristics
The effluent treatment plant is designed based on the analysis of effluent analysis report of combined effluent available with us. The relevant parameters are furnished below for your reference.
Parameter value
Ph: 9 -11
Bod: 600 mg/l
Cod: 1300mg/l
Suspended solids: 250mg/l
Total hardness: 50 mg/l
Turbidity: 150ntu
Color: 1000 pt.c0 units
Dissolved oxygen: nil
Tds: 2000 mg/l
After electro coagulation and filteration
Parameter value
Ph: 6.5-7.0
Bod: less than 50ppm
Cod: less than 150ppm.
Suspended solids: less then 5 ppm
Total hardness: 50 ppm
Turbidity: 5 ntu
Color: nil
Effluent treatment plant based on electro-coagulation and fluidized bed bio-reactor technologies.
Treatment steps
Primary treatment
Secondary treatment
Sludge management
Primary treatment
Bar screening
Collection and equalization
Neutralizing
Fluidized bed bioreactor
Secondary clarifier.
Activated sludge recirculation system
Secondary treatment
Electro-coagulation system
Flash mixer
High rate solid content clarifier
Pressure sand filter
Ec cleaning system
Sludge handling
Sludge thickener
Filter press
Sludge storage
Operating cost of etp
Etp tank size and water reserve capacity-
Equalization tank= height-20feet, capacity=2000m3
Fbbr tank= height-17 feet, capacity=1200m3
Secondary clarifier=height-10feet, capacity=0.8m3
Ec feed tank= height-10feet, capacity=60m3
Hrscc tank=height-12feet, capacity=0.8m3
Filter feed tank= height-10feet, capacity-140m3
Sludge tank= height-10feet, capacity-80m3
Total electricity consumption and cost in etp per day-
88 kw per day. Unit price- 89.75 taka/kw
Total cost=7898
Ec plate consumption per day-
Destroyed metal plate per day=254.66 kg.
unit price- 82 taka/kg
total cost= 20882 taka
join coupler used per day= 768 taka
Used chemical and cost per day-
Hcl-125 liter per day. Unit price is -6.60 taka/liter
Total cost= 825 taka
Poly electrolyte-400 gm per day. Unit price is- 1250 taka/kg
Total cost=500 taka
Dap= 5 kg. Unit price is- 33 taka/kg
Total cost=165 taka
Urea=5 kg. Unit price-12 taka/kg
Total cost= 60 taka
Molasses= 10 kg. Unit price is- 36.60 taka/kg
Total cost=366 taka
Total chemical cost per day= 1916 taka.
Man power cost-
Cost per day- 600 taka
Depreciation cost–
Total cost- 2, 50, 00, 000 taka
Life time of etp- 10 years
Depreciation cost per day = 6500 taka
Discharge water per day-
32, 40,000 liter per day or 3240 m3
Total cost per day-
38564 taka per day
Cost per liter-
11.90 taka per m3 for secondary clarifier design process
A sludge filter press pump is applied to feed the Treated Effluent from Flash mixer with solids & liquids through feed nozzle of the filter press to the chamber formed between the plates and the medium, leaving the solid trapped inside and the liquid drained out. Cake which is build in the hollow space between the plates will fall out once the pack is opened. Filter press is the most efficient and most employed in all filtering process.
Flocculation & Filteration
In the Electrocoagulation process, the Molecular Bonding of the Effluent breaks and the solids are separated and made to more stable form. After Electrocoagulation, An Anionic Poly Electrolyte is dosed from 0.5to 1 mg/L in the Flash Mixer. The Flocculation happens due to this and the bigger size flocs are formed for easier filtration. The Poly Electrolyte is dosed by the Dosing pump which is controlled as per the Flow rate of the Effluent. After the Flash mixer, the Filtration of the solids is done easily by Tube Settler or sludge filter press. The water becomes clear with out suspended solids and Turbidity after this filtration.
Filter Press
A High pressure diaphragm pump is applied to feed the concentrated sludge from high rate solid content clarifier with solids & liquids through feed nozzle of the filter press to the chamber formed between the plates and the medium, leaving the solid trapped inside and the liquid drained out. Cake which is built in the hollow space between the plates will fall out once the pack is opened. Filter press is the most efficient and most employed in all filtering process.
Main Use of Filter Press
To get crystal clear water
To Separate the sludge and water
To make sludge as dry form
To achieve the best results in DQO and DBO
To remove the Suspended solids
Filter Press Process Description
A High pressure Diaphragm pump is applied to feed the concentrated sludge from high rate solid content clarifier with solids & liquids through feed nozzle of the sludge filter press to the chamber formed between the plates and the medium, leaving the solid trapped inside and the liquid drained out. Cake which is built in the hollow space between the plates will fall out once the pack is opened. Filter press is the most efficient and most employed in all filtering process.
Function: This is a three step process : sludge removal, dewatering and disposal.
Sludge is removed from the HRSCC system from the bottom of sludge recirculation pipe line.
Filter Press
1.Filter Plate; 2 End Plate; 3.Rails ; 4.Hytrolic Jack 5.Plunger; 6 Inlet Pipe; 7.Filterate Discharge Pipe 8.Work Bench
Operation and maintenance consideration
The operator must record it filter press operation time (starting and finishing time of each batch) and no of batches collection from filter press.
The operators The desired quantity of polymer needs to be prepared 15-30 minutes before the dewatering operation .
The operator After every dewatering operation ,the filter cloths must be thoroughly cleaned. So that clogging in the pores of the woven polypropylene filter fabric is avoided.
The operator must clean Every three days once or Periodic cleaning of filter cloth with hydrochloric acid or hypo solution .
The operator note When the filtration process becomes excessively slow ,it is time to replace the filter cloth with a fresh set.
The operator always maintain stock list of filter cloth.
The operator always operate filter press 180 to 260 bar respectively.
When the outlet water quality is not good or high turbid content ,change the filter cloth or increases filtration pressure( 180 to 260 bar)
Trouble shooting
s.no
Problem
Cause
1
Filter press does not dewater the slurry sufficiently
Poor maintenance of filter press
2
Dewatering is very slow
Oily /slimy sludge filter press cloth is clogged improper conditioning.
3
Insufficient pressure developed
Rubber stator of screw pump work out.
Steel rotor damaged.
The freshly produced cake has a moisture content of between 70-75% .note that it is impossible to achieve a bone –dry cake even after prolonged air-drying; the moisture content would not drop below 50 %.The liquid in the slurry can pass through the cloth ,while the thickener paste-like sludge can not pass through the cloth.
Maine use of Filter press
To remove the moisture content in the final sludge
The electrocoagulation water treatment system process is based on valid scientific principles involving responses of water contaminants to strong electric fields and electrically induced oxidation and eduction reactions. This process is able to take out over 99 percent of some heavy metal cations and also able to precipitate charged colloids and remove significant amounts of other ions, colloids, and emulsions. Electrocoagulation water treatment system is based on the reactive anodes principle. It is a question of generating metallic cations (Al3+ or Fe3+) in wastewater by imposing a D.C. current between the electrodes. These cations act as a coagulant and lead to the destabilization of suspended particles and colloidal structure.
During the treatment, electrolysis reactions between the electrodes make it possible to produce micro bubbles. These finely divided bubbles drag suspended matter with them as they rise to the surface: hydrocarbons, oils, greases and colloids. At the end of the process, treated and decontaminated water is obtained. Electrocoagulation water treatment system is a technology that can be useful to all industries generating mineral or organic pollution. This Technology is ideally suitable for treating Textile Dyes Effluent
Electrocoagulation water treatment
Electrocoagulation is the process of destabilizing suspended, emulsified or dissolved contaminants in an aqueous medium by introducing an electrical current into the medium. The electrical current provides the electromotive force to drive the chemical reactions. When reactions are driven or forced, the elements or compounds will approach the most stable state. Generally, this state of stability produces a solid that is either less colloidal and less emulsified (or soluble) than the compound at equilibrium values. As this occurs, the contaminants form hydrophobic entities that precipitate and can easily be removed by a number of secondary separation techniques.
Electrocoagulation is an Unique and Latest technology successfully implemented in Developed and Developing Countries. The Advantages of electrocoagulation water treatment system ETP are as follows.
No addition of Chemicals, Lime or Ferric.
Very Low Operating Cost.
Less requirement of Space and Civil Construction.
Easy to maintain and operate.
Colour Removal more than 95%.
Electrocoagulation Water Treatment Process
Electrochemical techniques are important for the treatment of Textile wastewater because they present high efficiency, easy operation and environmental compatibility; this process involves in sit generation of coagulants by electrolytic oxidation of a sacrificial anode (iron) by applying a direct current. The most widely used electrode materials in electro coagulation process are iron. The hydrolyzed iron ions can form long chains of Fe-O-Fe-OH which may chemically adsorb a large amount of contaminating .For most applications a proper removal of all impurities ( Physical, biological and Dissolved impurities) of the water reused, is required.
After biological treated water is secondary clarifier and remove suspended particles and fed in to electrocoagulation water treatment system. The electro coagulation process works at input feed PH is 6.0 to 8.0 and conductivity >2000 milligrams/litre. Before and after were monitored for color, turbidity, pH and chemical oxygen demand reduction efficiency. Normally electro coagulation process reduces COD 50 to 60 % from input COD of electrocoagulation water treatment system process .
Working principle
Dissolution of metal ions from an electrode by applied potential.
Simultaneous evolution of H2 gas bubbles.
Destabilisation of suspension coagulation.
H2 bubbles promote flotation, but also sedimentation may occur.
Pair(s) of Fe or Al parallel plate electrodes separated by a few mm.
Electrocoagulation Chemical reaction
Main reactions occurring at the electrodes are:
In addition, Fe3+ and OH- ions generated at electrode surfaces react in the bulk waste water to form ferric hydroxide:
The iron hydroxide flocs act as adsorbents and /or traps for pollutants and so eliminate them from solution.
Electrocoagulation Merits
Overall, compared to conventional methods of treating wastewater involving physical and biological processes, electrocoagulation water treatment system is generally considered far more effective in removing pollutant. Not only that, it is also compact and space-saving and while there are arguments in terms of cost calculation, but however, to most experts’ opinion, it is actually cheaper to maintain in the long run.
Electro coagulation process (using iron electrodes) is a reliable, efficient and cost- effective method. quickest removal rate with the lowest cost.
Before start up EC PROCESS the operator must check EC input effluent PH ,it should be always greater than 6.5 and less than 8.5.
EC operates at PH 6.5 TO 8.5 .
Every day before start up, EC the operator must clean EC skid with HCl. The operator should maintain the PH of the diluted Acid as less than 2.0. If the cleaning acid PH greater than 2.0, must drain old acid(high PH acid > 2.0) and fill new hydro choleric acid and clean EC skid.
Every day The operator’s every one hour once give air circulation in to EC SKID .
Before start EC skid the operator must prepare poly electrolyte dosing chemical.
The operator must dose poly electrolyte 2 to 2.5 ppm in EC outlet water.
Every day The operator always take chemical stock list and material stock list (EC PLATES ).
If EC plant stop, the operator must drain EC skid water and well rinse EC SKID with treated water .
Every day the operators note EC voltage and current value and record it separate log sheet.
The operator every one hours once check EC TREATED WATER QUALITY. if water quality is not good increase current value and set correct current value. IF treated water more green color present reduced EC skid current value and set correct current value.
Conclusion
Every day once the operator must prepare poly electrocoagulation water treatment system dosing. Normally 5 to 7 days once the operators must change used cleaning acid or Acid PH greater than 2.0 change the cleaning acid. When EC PLATE changing period the operator must note EC plates are sited in the mounding grid properly. It is very essential for any textile industry.
We selected 210 m3 capacity existing concrete activated sludge tank for bio cultivation process. Maintained mlss as 3000 mg/litre 7000 mg/litre , do value maximum 4 mg/litre and minimum 1.0 mg/litre., ph 6.5 to 7.9 , sv-30 as 300 to 500 ml/litre, temperature is < 37 degree celsius and constant feed flow rate. Control of the activated sludge tank process is important to maintain a high treatment performance level under a wide range of operating conditions
Activated sludge treatment
After equalization process using acid to reduce ph from 9.0 to 6.5. After neutralization process the effluent are giving constant feed flow rate 20 m3/hr into bio tank. Here 20 m3 to 24 m3/hr is re circulated from secondary clarifier and fed in to bio tank process .the heavy organic solids, gradually fed into biological tank ( capacity 210 m3 ) process containing millions of microorganisms that can only survive and multiply in an environment containing free oxygen that is dissolved in the water and a food source. This method for treating wastewater is referred to as the activated sludge process. Oxygen is provided by pumping and diffusing air (similar to how air is pumped and diffused in a fish aquarium) into large tanks containing the microorganisms and raw effluent. The mixture of microorganisms, raw effluent and dissolved oxygen is referred to as mixed liquor suspended solids (mlss). After the aeration period, the mlss is transferred to secondary clarifier, where it is allowed to settle by gravity leaving a clear liquid referred to as electro coagulation feed effluent . While the settled mlss is returned to the aeration tanks to maintain the appropriate population and cultures of microorganisms. Return of the mlss from secondary m clarifier tanks to the front of the aeration tanks is referred to as return activated sludge (ras). As the microorganisms multiply, the amount of food available in the raw effluent will become insufficient and the quality of treatment can degrade. . This wasting is referred to as waste activated sludge (was) ,this excess sludge tank fed in to sludge bed and reused ( like natural fertilizer) . After biological process input raw effluent cod reduces minimum50%.
Biological process reaction :
Important maintaince of process:
The principal factors in procedure control are the subsequent:
Maintenance of dissolved oxygen levels within the aeration tanks.
