The document discusses various processes for treating textile wastewater, including physical/chemical and biological methods. Textile wastewater contains pollutants from processes like dyeing, printing, and finishing. It discusses synthesizing wastewater for testing purposes and describes the properties of sludge. Color removal can occur through adsorption or reduction of azo dyes. Factors like oxygen, temperature, pH, and dye structure impact color removal efficiency. Common treatment methods include oxidation, adsorption, membranes, coagulation, activated sludge, and anaerobic digestion.
Azo dyes are one of the oldest industrially synthesized organic compounds characterized by presence of Azo bond (-N=N-) and are widely utilized as coloring agents in textile, leather, cosmetic, paint, plastic, paper, and food industries During textile processing, inefficiencies in dyeing result in large amounts of the dyestuff (varying from 2% loss when using basic dyes to a 50% loss when certain reactive dyes used) is being directly lost to the wastewater, which ultimately finds its way into the environment. The physico-chemical method of industrial effluent treatment does not remove the dyes effectively. Microbial degradation and decolorization of azo dyes has gained more attention recently because of eco-friendly and inexpensive nature. Microbes and there enzymes could decolorize the dyes by both aerobic and anaerobic metabolis. This review provides a general idea of decolorization and biodegradation of azo dyes with various microbes and highlights the application of for the treatment of azo dye-containing wastewaters.
Removal of dye from polluted water using novel nano manganese oxide-based mat...Dr. Md. Aminul Islam
Dyes are priority pollutants, commonly found at significant concentrations in textile effluents. The presence of dyes stuffs in wastewater can cause severe problems to aquatic life and human beings. Therefore, the removal of dyes from wastewater is important in order to minimize their hazardous effects on the environment. One way of removing dyes is to use nanosized manganese oxides (MnOs). To date, there has been much work reported on the use of nanosized MnOs as sorbents for dyestuffs. They are promising sorbents for commercial use due to their amorphous nature, high specific surface areas (SSA), mesoporous structure, and low to the moderate point of zero charge (pHPZC). This review summarizes the toxicity and recent advances for removing dyes from wastewater using nanosized MnO sorbents. The article also describes the various experimental parameters necessary for adsorption optimization, such as adsorption time, pH, initial dye concentration, amount of sorbent and temperature. Adsorption mechanisms investigated by various modeling approaches are also discussed. In particular, it was observed that much work has been reported on the use of birnessite and its composites for dye removal. There are many papers reporting on the use of MnO in batch mode dye removal, but very few that report on the use of MnO in continuous column removal systems. Therefore, there is still a considerable need for further research to develop effective and economical large scale MnO column systems for commercial use.
Dye effluents impose hazardous effects on human beings as well as on environment. The present powerpoint deals with some of the decolourization techniques that can be adopted for treating wastewater containing toxic dyes and chemicals
Azo dyes are one of the oldest industrially synthesized organic compounds characterized by presence of Azo bond (-N=N-) and are widely utilized as coloring agents in textile, leather, cosmetic, paint, plastic, paper, and food industries During textile processing, inefficiencies in dyeing result in large amounts of the dyestuff (varying from 2% loss when using basic dyes to a 50% loss when certain reactive dyes used) is being directly lost to the wastewater, which ultimately finds its way into the environment. The physico-chemical method of industrial effluent treatment does not remove the dyes effectively. Microbial degradation and decolorization of azo dyes has gained more attention recently because of eco-friendly and inexpensive nature. Microbes and there enzymes could decolorize the dyes by both aerobic and anaerobic metabolis. This review provides a general idea of decolorization and biodegradation of azo dyes with various microbes and highlights the application of for the treatment of azo dye-containing wastewaters.
Removal of dye from polluted water using novel nano manganese oxide-based mat...Dr. Md. Aminul Islam
Dyes are priority pollutants, commonly found at significant concentrations in textile effluents. The presence of dyes stuffs in wastewater can cause severe problems to aquatic life and human beings. Therefore, the removal of dyes from wastewater is important in order to minimize their hazardous effects on the environment. One way of removing dyes is to use nanosized manganese oxides (MnOs). To date, there has been much work reported on the use of nanosized MnOs as sorbents for dyestuffs. They are promising sorbents for commercial use due to their amorphous nature, high specific surface areas (SSA), mesoporous structure, and low to the moderate point of zero charge (pHPZC). This review summarizes the toxicity and recent advances for removing dyes from wastewater using nanosized MnO sorbents. The article also describes the various experimental parameters necessary for adsorption optimization, such as adsorption time, pH, initial dye concentration, amount of sorbent and temperature. Adsorption mechanisms investigated by various modeling approaches are also discussed. In particular, it was observed that much work has been reported on the use of birnessite and its composites for dye removal. There are many papers reporting on the use of MnO in batch mode dye removal, but very few that report on the use of MnO in continuous column removal systems. Therefore, there is still a considerable need for further research to develop effective and economical large scale MnO column systems for commercial use.
Dye effluents impose hazardous effects on human beings as well as on environment. The present powerpoint deals with some of the decolourization techniques that can be adopted for treating wastewater containing toxic dyes and chemicals
Decolorization of mixture of dyes: A critical reviewGJESM Publication
Water plays a vital and essential role in our ecosystem. This natural resource is becoming scarce, making
its availability a major social and economic concern. Use of a large variety of synthetic dyes in textile industries has raised an hazardous environmental alert. About 17 - 20% of freshwater pollution is caused by textile effluents. These effluents are recalcitrant to biodegradation and cause acute toxicity to the receiving water bodies, as these comprised of various types of toxic dyes, which are difficult to remove. Decolorisation of textile wastewater is therefore important before releasing it into the nearby local waterways. It therefore becomes essential to degrade the toxic chemicals of textile wastewater, so as to avoid the hazardous environmental effects. Several treatment methods have been employed to embark upon the problem of dye removal but degradation becomes further more difficult for effluents containing dye matrix. The
review study has been an attempt to present the different diversified attempts used for decolorisation of a mixture of dyes.
Dye removal by adsorption on waste biomass - sugarcane bagasseMadhura Chincholi
The dye solution of Methylene blue was adsorbed onto bioadsorbent- sugarcane bagasse. Parameters studied were pH, contact time, adsorbent dosage, initial dye conc.
Comparative Study for Adsorptive Removal of Coralene Blue BGFS Dye from Aqueo...IJERA Editor
Textile industries represent biggest impact on the environment due to high water consumption and waste water discharge as government control water pollution by setting strength regulation for waste water discharge, removal of color from waste water becomes more and more essential and attractive. Adsorption technology is very efficient in treatment of textile effluent. In this paper comparison of adsorption phenomena of textile dye Anthraquinone blue onto two different adsorbents MgO nano powder and Fe2O3 amorphous powder has been studied for removal of said dye from aqueous solutions. The adsorption of Anthraquinone blue on adsorbents occurs by studying the effects of adsorbent amount, dye concentration, contact time and pH of solution. All results found that MgO nano powder and Fe2O3 provide a fairly high dye adsorption capacity, which combined with their fulfilment of pollution control board’s standards, lack of pollution, lower environmental hazard and low-cost makes them promising for future applications. The present work also provides information on optimum value of different operating parameter for dye removal by two adsorbent.
Decolourisation of Nigrosine WS dye by Solar Photo-fentonAkash Tikhe
My master's dissertation thesis topic- Decolorization of Nigrosine WS dye by Homogeneous Solar Photo-Fenton Method along with Intro, Method, Result, conclusion and suggestions.
ADSORPTION OF CONGO RED DYE AND METHYLENE BLUE DYE USING ORANGE PEEL AS AN A...Ajay Singh
To reduce the concentration of the dye activated charcoal is used as an adsorbent but due to the high cost of activated charcoal, the purpose of my project was to find an alternative low-cost adsorbent.
Desarrollo tecnológico y científico en Colombia, se detallara su crecimiento o su equilibrio en la sociedad y como adoptan los ciudadanos colombianos estos datos.
Decolorization of mixture of dyes: A critical reviewGJESM Publication
Water plays a vital and essential role in our ecosystem. This natural resource is becoming scarce, making
its availability a major social and economic concern. Use of a large variety of synthetic dyes in textile industries has raised an hazardous environmental alert. About 17 - 20% of freshwater pollution is caused by textile effluents. These effluents are recalcitrant to biodegradation and cause acute toxicity to the receiving water bodies, as these comprised of various types of toxic dyes, which are difficult to remove. Decolorisation of textile wastewater is therefore important before releasing it into the nearby local waterways. It therefore becomes essential to degrade the toxic chemicals of textile wastewater, so as to avoid the hazardous environmental effects. Several treatment methods have been employed to embark upon the problem of dye removal but degradation becomes further more difficult for effluents containing dye matrix. The
review study has been an attempt to present the different diversified attempts used for decolorisation of a mixture of dyes.
Dye removal by adsorption on waste biomass - sugarcane bagasseMadhura Chincholi
The dye solution of Methylene blue was adsorbed onto bioadsorbent- sugarcane bagasse. Parameters studied were pH, contact time, adsorbent dosage, initial dye conc.
Comparative Study for Adsorptive Removal of Coralene Blue BGFS Dye from Aqueo...IJERA Editor
Textile industries represent biggest impact on the environment due to high water consumption and waste water discharge as government control water pollution by setting strength regulation for waste water discharge, removal of color from waste water becomes more and more essential and attractive. Adsorption technology is very efficient in treatment of textile effluent. In this paper comparison of adsorption phenomena of textile dye Anthraquinone blue onto two different adsorbents MgO nano powder and Fe2O3 amorphous powder has been studied for removal of said dye from aqueous solutions. The adsorption of Anthraquinone blue on adsorbents occurs by studying the effects of adsorbent amount, dye concentration, contact time and pH of solution. All results found that MgO nano powder and Fe2O3 provide a fairly high dye adsorption capacity, which combined with their fulfilment of pollution control board’s standards, lack of pollution, lower environmental hazard and low-cost makes them promising for future applications. The present work also provides information on optimum value of different operating parameter for dye removal by two adsorbent.
Decolourisation of Nigrosine WS dye by Solar Photo-fentonAkash Tikhe
My master's dissertation thesis topic- Decolorization of Nigrosine WS dye by Homogeneous Solar Photo-Fenton Method along with Intro, Method, Result, conclusion and suggestions.
ADSORPTION OF CONGO RED DYE AND METHYLENE BLUE DYE USING ORANGE PEEL AS AN A...Ajay Singh
To reduce the concentration of the dye activated charcoal is used as an adsorbent but due to the high cost of activated charcoal, the purpose of my project was to find an alternative low-cost adsorbent.
Desarrollo tecnológico y científico en Colombia, se detallara su crecimiento o su equilibrio en la sociedad y como adoptan los ciudadanos colombianos estos datos.
Cationic and anionic dye adsorption by agricultural solid wastes: A comprehen...IOSR Journals
Dyes are an important class of pollutants, and can even be identified by the human eye. Disposal of dyes in precious water resources must be avoided, however, and for that various treatment technologies are in use. Among various methods adsorption occupies a prominent place in dye removal. Recently many researchers have proved that agricultural solid wastes can be effectively used as adsorbents for the removal of many pollutants including dyes. This review represents the effectiveness of agricultural solid wastes in the removal of dyes, of cationic and anionic classes, description of classification of dyes and comparison among cationic and anionic dyes adsorption by the same adsorbent, thus, possibly opening the door for a better understanding of the dye classified adsorption process. Both these classes of dyes are toxic and cause severe problems to aquatic environment. Some agricultural solid wastes can remove both dye classes. The dye adsorption capacities of agricultural waste adsorbents vary along with the variation in pH of solution, initial dye concentration, adsorbent dosage and process temperature. As the pH of the solution affects the surface charge of the adsorbent and degree of ionization of the adsorbate, it is directly related to the dye classified adsorption. This review also contains the table representing the adsorbent and subsequent dye/dyes appropriate for a particular process. Conclusions have been drawn from the literature reviewed, and suggestions for future research are proposed.
Equilibrium Studies of Malachite Green from Aqueous Solution Using Corn Cob a...IJERD Editor
The objective of this work is the study of adsorption of dye solution which is a dye malachite green
using corn cob. Removal of this dye from aqueous solution using corn cob has been investigated. Liquid phase
adsorption experiments were conducted. Batch adsorption studies are Carried out by observing the effect of
experimental parameters, namely, pH, and amount of adsorbents, contact time and initial concentration.
Optimum conditions for dye removal are studied like pH value, contact time required, amount of adsorbent,
initial concentration, etc. The results generated by this work can be used for determination of optimum
conditions for adsorption of dye in aqueous solutions. Dye is present in mixture form in various Industrial
effluents like Textile Industries, Sewage water, Water treatment plants. This work can have use in Design of
adsorption columns for dyes removal. The Freundlich adsorption model assumes that adsorption takes place on
heterogeneous surfaces. Adsorption increases with increase in pH. The adsorption of cationic dye is mainly
influenced by the amount of negative charges in the solution which is actually influenced by the solution pH. At
pH=2 there is net positive charge in the solution so adsorption is less whereas at pH=12there is increase in
negative charges increasing adsorption of malachite green. Maximum adsorption was found to take place at
pH=12. Adsorption tends to increase with contact time. At first the increase in adsorption is very rapid as there
are lots of free sites for the adsorption to take place. Adsorption decreases at later stages till saturation is reached
due to saturation of active sites. The optimum contact time for equilibrium was found to be 100 min.
Removal of Methylene Blue from Aqueous Solution by Adsorption using Low Cost ...ijsrd.com
The present study deals with removal of methylene blue (basic dye)from aqueous solution using a low cost activated carbon prepared from Delonix regia(gulmohar seed pods).Batch adsorption studies were conducted by varying the contact time adsorbent dosage and pH
Applicability of Fenton Process for Treatment of Industrial Effluents: A ReviewIJERA Editor
Wastewater and effluent treatment has undergone innovative changes over the years. Traditional wastewater treatment has yielded to modern and path-breaking procedures which are more efficient and effective. The world of difficulties and unknown has opened new avenues and paths to highly feasible effluent treatment procedures, so the vigorous importance of advanced oxidation procedures. This review paper will delineate the increasing importance of various advanced oxidation processes including Fenton treatment for wastewater. Advanced oxidation processes (AOP’s), which involve and includes the in-situ generation of highly potent chemical oxidants such as the hydroxyl radical, have emerged as an important avenue of technologies to accelerate the non-selective oxidation and thus the destruction of a wide range of non-degradable organic contaminants in wastewater which cannot be eliminated biologically. Advanced oxidation processes (AOP) are technologies based on the generation of highly reactive species, the hydroxyl radicals, used in oxidative degradation procedures for organic compounds dissolved or dispersed in aquatic media. These processes are promising alternatives for decontamination of media containing dissolved recalcitrant organic substances, which would not be efficiently removed by conventional methods.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
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The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
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Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
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This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
CLASS 11 CBSE B.St Project AIDS TO TRADE - INSURANCE
water mangement
1. Introduction
Textile production involves number of wet process like, finishing
,drying ,dyeing, printing, bleaching, washing, desizing etc. Each
process generates wastewater containing different type of pollutants
like dyes sizing agents, salts and dyeing auxiliaries . For fixing of dyes
different types of salt are used like sodium chloride,sodium
sulphate,sodium nitrate and sodium carbonate etc.scouring and
desizing process.azo dyes are mostly used in dyeing process.azo
dyes cause coloured wastewater.azo dyes have electron withdrawing
capacity due to n=n bond.in conventional treatment it is difficult to
decolourise the textile wastewater.for treatment of textile waste
water various physicochemicals(like coagulation,membrane
filtrationand adsorption)advanced oxidation process(fenton ultra
violet and h2o2 oxidation) biological processes(conventional activate
sludge and extended qeration activated sludge)
A combination of these processes can also be applied for treatment
of textile wastewater.
2 synthetic waste water composition:-
The composition of synthetic wastewater is as follows[muda et
al.2010]:-
Nh4cl 0.16 g/l ,kh2po4 0.23 g/l k2hpo4 0.58 g/l,
Cacl2.2h2o .07 g/l,mgso4.7h2o 0.09 g/l, edta 0.02 g/l and trace
solution 1 ml/l.
The carbon sources used were glucose 0.5 g/l.
2. The composition of trace elements was h3bo3 0.15g/l ,fecl3 1.5
g/l,zncl2 0.12 g/l mncl2.4h2o 0.12 g/l fecl3.4h2o 1.5 g/l zncl2 0.12 g/l
namoo4.2h2o 0.06 g/l,cocl2.6h2o 0.15 g/l
And ki 0.03 g/l . The ph of synthetic wastewater was approximate to
7
3 sludge
It is residual material left from industrial waste water or sewage
waste water processes. It consists of micro-organisms,non-living
organic matter & inorganic materials.
Physical properties of sludge
3.1.1 size
The avg. Dia of microbial granular slude is 2.3+_1.0mm according to
muda et al 2010.according to peng et al 1999,the diameter of
developed aerobic granules is in the range of 0.3-0.5 mm which is
smaller as compared to aneorbic granules that can be upto 2 to 3
mm.
3.1.2
Settling velocity
For seed sludge the avg. Settling velocity was 9.9+_0.7
M/l
And for seed anerobic granular sludge it was 42+_8 m/h
3. [muda et al 2010]. The avg settling velocity of the anerobic granular
seed is in range of 18-100m/h by schmit and ahring 1996.at the end
of experiment avg settling velocity for granular sludge was increased
from 17.8+_2.6 m/h to 80+_8m/h.
Developed microbial granular sludge posseses
High settling velocity.
This enabled the granules to escape from being flushed out.generally
as the no. Of operational days increases the bio mass concentration
and settling velocity also incresses.
3.1.3 granular strength
The granular strength of the granules was measured based on
integrity coefficient [ghangrekar et al 2005].if ic value is small ,then
strength will be higher.generally as the operation days increases as ic
value decreases. According to ghangrekar et al 2005 granules which
have ic value less than ware considered high strength granules.
The microbes in the granules were loosely linkes at the early stage of
granular development.as more microbes were linked together , the
granules increased in size. So the microbes produces more eps that
causes the granules to become denser and stronger.
3.1.4. Mineral content
There are some mineral present in sludge like na+ k + ca2+ mg2+ etc
Mechanism of colour removal
Yhe mechanisim of colour removal is adsorption of the dye onto the
biomass (brass et al 2001).
In during adsorption ,the dye is concentrated onto biomass.
4. Bio association b/w the dye and the bacterial cells tends to the
biological reduction of azo dyes .most of the azo dyes have
sulphonates substituents groups and a high molecular weight.
1 there are two mechanism for the decoloration of azo dyes as
terminal electron during bacterial catabolism connected to atp
generation
2 a gratuitons reduction of azo dyes by the end products of bacterial
catabolism not linked to atp generation.
Factors affecting colour removal
The composition of textile waste water include organics, nutrients,
salts, sulphur compound , toxicants and colour .
Any of these compounds may create inhibition to dye reduction
process.
1 oxygen
This is the most important factor to consider in color removal
process .it is the effect of oxygen on cell growth and dye reduction.in
aerobic condition during the reduction stage oxygen may inhibit the
dye reduction mechanism .because the electron doners by the cells
is used to reduce oxygen rather than the azo dye.for efficient colour
removal should be avoided[chang et al 2000]in aerobic condition
after reduction of azo bond there is no further reduction of yhe dye
molecule.
2temperature
5. In many system the rate of color removal increase with with
increasing temperature. The temperature required to produce the
max rate of colour removal tends to optimum cell culture growth
temperature of 35-45 c
3 ph
The optimum ph for colour removal is approximately 7 or slightly
alkaline value .the reduction of azo bond can increase the ph value
due to formation of the aromatic amines.
4 dye concentration
The concentration of dye can affect the efficiency of colour removal
4dye structure
Dyes those have simple structure and low molecular weight.they
exihibit higher rates of color removal but for highly substituted and
high molecular weight dyes , color removal is difficult.
In dyes when electron withdrawing group like –so3h -s02nh2 are in
the para position of the phenyl ring , relative to the azo bond their
causes an increase in the reaction rate.
Colour removal also depends on the no if azo bonds in the dye
molecule .the colour of the monoazo dye is removed faster than is
the colour of diazo or triazo dye according to hiltz et al
A acid dyes exihibit low colour removal due to a no of sulphonate
group in the dye
6. B direct dye exihibit high level of colour removal
C reactive dye eihibit low levels of colour removal
Electron donor
According to bras et al ,the addition of electron donor such as
glucose or acetate ions increases the reduction cleavage of azo bond.
Coenzyme reducing equivalents act as the electron donors for azo
dye reduction
Redox potential as rate determining step involves a redox
equilibrium b/w/ the dye and reducing agent.so colour removal
depends on the redox poentialof the electron donor and electron
acceptors.if the redox potential of the system is at most negative
then colour removal rate will be highest.if we increases redox
potential of the system , the colour removal rate decreases.
Technologies available for colour removal
There are two possible location :-
1 at the dye house ,to remove colour
2 at the sewage works to treat colour
Methods of treatment of waste water
7. 1 physical/chemical methods
Oxidation
Adsorption
Membrane technologies
Coagulation/flocculation
2
Conventional active sludge
Entended aeration activated sludge
Oxidation
Oxidative process representes a widely used chemical method for
the treatment of textile wastewater treatment.the main oxidizing
agent is h2o2.hydrogen peroxide is added to an cidic solution (ph =2-
3) containing fe2+ ions.it is called fenton reaction .it mainly used in
pre-treatment. The reaction is exothermic and it takes place at high
temperature.the great amount of total cod removes to fe(oh)3 co-
precipitation .the main drawback of this method are the significant
addition of acid and alkali to reach required ph , to high discharge in
final effuluent.
The ozone oxidation is also a very effective decolourising process
ozone can easily vreak the double bond of the dyes. It can oxidize a
significant portion of cod.
The –ve effect carcinogenic aromatic amines, i.e toxic.
Adsorption
8. In this process the mixing of waste water and the porous material
powder orgranules occurs.in this method ,the pollutants in the waste
water are removed on the surface of the porous material of filter
commonly used adsorbents are activated carbon ,silicon polymers nd
kaolin
Membrane separation process
In this method the membrane’s micropores are used to filter and to
separate certain substance in wastewater .this method is based on
membrane pressure some of the methods are reverse osmosis
ultrafiltration ,nano filtration and microfiltration.
Coagulaton flocculation sedimentation
Colloidal type of very small type material have electrical changes
.these changes give repulsion and prevent their aggeration by adding
water electrolytic products,ployelectrolyte can eliminate the surface
charges of the colloids .this effect is known as coagulation.
Biologica wastewater treatment
According to different oxygen demand biological treatment methods
can be divided into aerobic and anaerobic treatment.
Aerobic biological treatment
According to the oxygen demand of different bacteria , the bacteria
can be divided into aerobic bacteria . Anaerobic bacteria an
dfacultative bacteraia.
9. Aerobic biological treatment can be divided into major categoried :-
activated sludge process-
Activate sludge is a kind of floc which is mainly comprised of many
microorganisms and has strong ddecomposition .in present the
oxidation ditch and sbr process are commonly used activated sludge
process
Oxidation ditch
The oxidation ditch is generally consisted of the ditch body of ring
shape. Wastewater activated sludge and various micro organisms are
mixed in a loop ditch oxidation ditch has a long hrt; low organic
loading and long sludge age . It has high purification stable reliable
,simple,easy,low investment and energy consumption.
Sequencing batch reactor activated sludge process
Its operation is mainly composed of five processes-
1 inflow
2 reaction
3 sedimentaton
4 outflow
5 standby.
Sbr process have high removal rate of cod as well as high removal
efficiency of colour.
10. Anaerobic biological treatment
In this method the anaerobic bacteria used. This is a good method
for treatment of waste water .the uasb reactor is used for treatment
of simulated textile wastewater.
As azo dyes have n=n bond in structure ,thereore their
biodegradation are impossible under aerobic condition .in aerobic
condition oxygen are used as electron acceptor instead of azo dye .
In anaerobic condition azo dye are used as electron acceptor ,so
breakdown of n=n bond occurs .thus decolouration is possible.
Conclusion
The salt concentration of 32g/l was optimum for 82.5% removal of
cod at a hrt of 20 h . At 128 g/l cod removal efficiency decreased to
18.5% in vasb reaction generally as nacl concentratioion of usab
reaction increases cod removal efficiency decreases [isik,2004],state
operation is possible with salt concentration up to 27-30g nacl .clolur
removal efficiencies were not affected with ncreasing salt
concentration in usabreactor.
After the ssalt concentration of 32g/l , the methanogenic bacteria
could be inhibited. The high salt concentration reduces methane
percentage.
it si possible to obtain high decolouration yields of
azo dyes in methanogenic usab reactor (bras et al 2005).higher
decolouration yield is obtained for diazo than monoazo (bras et al
2005).
11. Combines anaerobic – arobic usab reation a method for complete
removal of azo dyes from wastewater.at higher hydraulic retention
time. The colour removal efficiency can be used in both aerobic &
anaerobic.