Textile Processing Industries Research Articles

Industrial applications of shock waves

Shock waves have been traditionally considered to be an integral part of flow field features in the area of high-speed aerodynamics. Physically the propagation of shock waves in any media is invariably associated with instantaneous increase in pressure and temperature behind the shockwave. The capability of shock waves to generate non-linear pressure and temperature spikes in the medium of propagation finds very interesting applications in variety of areas such as medicine, biological sciences, material processing, manufacturing, and microelectronic industries. This paper reviews four new industrial applications of shock waves that have been developed in the Shock Waves Laboratory (SWL), Department of Aerospace Engineering, IISc, Bangalore. They are shock wave assisted (a) cell transformation, (b) preservative injection into Bamboos, (c) sandal oil extraction, and (d) removal of micron size dust from silicon wafer surfaces. The shock waves generated in an underwater shock wave generator are exploited in successfully injecting the desired deoxyribonucleic acid into Escherichia coli and Agrobacterium cells. The vertical shock wave reactor is applicable in successfully injecting the water-soluble chemical preservative (copper—chrome—arsenic) to samples of bamboo. The exposure of sandalwood samples to shock wave loading in the horizontal diaphragmless shock tube resulted in the drastic reduction (40 per cent) of time required for oil extraction. Further, a new shock wave assisted technique for micron-size dust removal from silicon wafer surfaces has been developed in collaboration with the Interdisciplinary Shock Wave Research Center, Tohoku University, Sendai, Japan. The strong vortex field generated behind the Mach reflection of a shock wave has been used to remove micron size dust particles from the surface of silicon wafers. The salient features of these new industrial applications of shock waves are described in this paper along with some important results.

Textile coloration industry in India

This review paper discusses the diversity of the textile sector in India, including its nature, the number of stakeholders and its effect on the overall national economy. It focuses on the significant role the coloration industry is expected to play in the near future, as this is the most problematic step in textile production with respect to profitability, planning and technology. While carrying out analysis of the textile and clothing industry, it also deals with the transformation the industry has undergone in the last two decades in terms of the selection of textile product mix in different regions of India from the point of view of profitability, the use of modern technology and selection criteria of colourants and specialised chemicals. These changes are viewed in respect of improved quality demands, measures undertaken to minimise the pollution level of the environment, and other related factors. In parallel, the growth of the dyestuff and speciality chemical industry, which has a direct relationship with this industry, is also discussed. It attempts to reflect upon the efforts of the Indian government in encouraging modernisation of the textile processing industry in terms of the Technology Upgradation Fund Scheme and other policy supports in relation to the response from the industry. Finally, the paper highlights the amount of human resource development needed to achieve the ambitious targets the government has put before the textile and clothing industry.

Ultrafiltration as a pre-treatment of other membrane technologies in the reuse of textile wastewaters

Water consumption in textile processes is very high and moreover a large amount of polluted effluents is generated. Many textile industries perform only a biological treatment of these effluents. In countries with water scarcity, the reuse of the secondary effluents represents an interesting solution. In this work, ultrafiltration (UF) has been studied as a pre-treatment of nanofiltration (NF) and reverse osmosis (RO) in the reuse of the secondary effluent of textile wastewaters from different processes of textile industry. In the first experimental stage, experiments in a flat module were carried out with four UF membranes in order to select the most suitable one. The secondary effluent after a 50 micron cartridge was treated and the COD was analyzed. According to the highest COD removal, the membrane selected was the IRIS 3028 from Rhodia–Orelis with a cut-off of 10 kDa. In the second stage, experiments were performed with the membrane selected in a spiral-wound module. The aim of these experiments was to characterize the membrane performance and to optimize the cleaning procedure. The results showed that the COD removal obtained with this membrane was not enough to directly reuse the permeate in the industry. However, the permeate quality obtained guaranteed optimal conditions for its use as a NF feed. The combined UF/NF process was more efficient than a process exclusively based on NF as the NF fouling was reduced considerably and the total water recovery was higher.

Plasma technology in wool

The textile industry processes a large quantity of fibres obtained from various animals of which wool is commercially the most important. However, it has some technical problems which affect the quality and performance of the finished products such as felting shrinkage, handle, lustre, pilling and dyeability. These problems may be attributed mainly to the presence of wool scales on the fibre surface. The scales are relatively hard and have sharp edges which are responsible for causing fibre directional movement and shrinkage during felting. Furthermore, the scales also serve as a barrier for diffusion processes which will adversely affect the sorption behaviour. In recent years, there has been an increase in the modification of wool surface scales by physical means such as mechanical, thermal and ultrasonic treatments, and chemical methods such as oxidation, reduction, enzyme and ozone treatments which can solve the felting and sorption problems to a certain extent. Hitherto, chemical treatments are still the most commonly used descaling methods in the industry. Owing to the effect of pollution caused by various chemical treatments, physical treatments such as plasma treatment have been introduced recently as they are capable of achieving a similar descaling effect. Since the 1960s, scientists have successfully exploited plasma techniques in materials science. The plasma technologies have been fully utilised to improve the surface properties of fibres in many applications. The fibres that can be modified by plasmas include almost all kinds of fibre such as textile fibres, metallic fibres, glass fibres, carbon fibres, fabrics and other organic fibres. Plasma-treated wool has different physical and chemical properties when compared with the untreated one. The changes in fibre properties alter the performance of the existing textile processes such as spinning, dyeing and finishing to produce a series of versatile wool products with superior quality. Therefore, the aim of this monograph is to give a critical appreciation of the latest developments of plasma treatment of wool. In this monograph, different surface treatments of wool including plasma treatment will be precisely described. Since plasma treatment can be used to alter material surfaces by removing outer layers, thus the method of generation of plasma and the reaction mechanisms between material surface and plasma species will be highlighted in this monograph. Similar to other chemical reactions, the factors such as (i) the nature of gas used, (ii) gas flow rate, (iii) system pressure and (iv) discharge power affecting the final results of plasma treatments will be described. The main content of this monograph includes the application of plasma treatment on wool under different industrial conditions such as dyeing and shrinkproofing processing which will be reported and discussed respectively. In addition, the common analytical methods such as Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy and Fourier Transform Infrared Spectroscopy with Attenuated Total Internal Reflectance mode analysis employed for characterising the surface properties of plasma-treated wool will be discussed. Based on the surface characterisation results, more details about the mechanism of plasma treatment that affects the wool processing such as dyeing and shrinkproofing can be explored. In the latter part of the monograph, the serviceability of plasma-treated wool fabrics is discussed and the possibility of applying the plasma-treated wool fabric to industrial use is evaluated based on standard performance specification, e.g. ASTM. The fabric performance in terms of tailorability and sewability are also discussed with reference to the Kawabata Evaluation System for Fabric (KES-F) results. As the plasma process is a “dry” process, i.e. the water used in the plasma system can be recycled, thus it can solve the industrial effluent problem resulting in providing an effective means for the modification of wool fabrics.

Environmental impact assessment during project execution phases: towards a stage-gate project management model for the raw materials processing industry of the energy sector

Environmental impact assessments (EIAs) are usually required for all projects in the raw materials processing industry of the South African energy sector; they range in comprehensiveness from screening or abridged to full EIAs. Technical projects are typically on extremely tight schedules and project managers are tasked to properly align project lifecycles with the EIA process. However, the South African EIA legislation fails to take project management models and practices into consideration. A survey was conducted to establish the model that is usually followed. It focused on the stages of an EIA in relation to the project execution lifecycle phases. It ascertained problems that currently exist with the EIA procedure in the raw materials processing industry of the energy sector and that negatively affect the efficiency of project management practices in South Africa. Possible solutions are discussed and a stage-gate model is subsequently proposed, whereby the proper alignment of the South African EIA process and a typical project lifecycle is ensured for the energy sector. Further research is required to test the model through South African cases to determine the benefits and inefficiencies of such an approach, its critical elements such as quality assurance, and its influence on the stakeholders involved in an EIA.

Nanofiltration for recovering wastewater from a specific dyeing facility

Textile processing industry generally requires significant amount of process water for cleaning, rinsing and dyeing purposes. Advanced membrane separation with high efficiency, ease and economic of operation as one of the most promising technologies has become increasingly attractive for reclamation of wastewater due to the shortage of fresh water supplies caused by the development of global population and industry. The objective of the study was to investigate the feasibility for recovering the wastewater from a specific dyeing facility by nanofiltration (NF). Process review at the dyeing facility was conducted and wastewater streams were characterized. A bench scale unit with total membrane area of 465 cm 2 was used in this study. Trials were conducted to recover the wastewater using three types of NF membranes. The results indicated that the NF membrane process performed high efficiency of >99% for dye removal and NE-70 membrane showed better performance in terms of flux and separation than Desal-5 membrane. Turbidity, hardness, TOC and color of the treated water were less than 0.2 NTU, 60 mg/L as CaCO 3, 10 mg/L and 5 HU, respectively. It could be concluded that it was feasible to recover 70% of the wastewater from the dyeing facility using a NF membrane process and the quality of the treated water could meet the requirements of dyeing process.

Thermal history analysis of surface heating of mild steel with different laser beam geometries

Lasers are in use in the material processing industry for well over 30 years now. The way in which the temperature is distributed inside the material is of prime importance in laser material processing, as it directly affects the heating/cooling rates and thermal gradients. Optimization of different laser processes requires control over heating/cooling rate and thermal gradient. Different processes have different requirements of heating/cooling rate and thermal gradient. Knowing these parameters and relevant metallurgical information, one can predict the microstructure and hence control the material properties. To date, majority of laser processing is carried out by using either circular or rectangular beam. At present, the variation in temperature distribution to control the heating/cooling rates and thermal gradients is caused by the variation either in laser power or in scanning speed. Variations in these parameters are often limited by other processing conditions. Although different beam intensity distributions with circular or rectangular laser beams have been studied to improve the process, no other beam geometries have been investigated. The effect of laser beam geometry on laser processing of materials has received very little attention. This article presents an investigation of the effects of different beam geometries including circular, rectangular, and triangular shapes on heating of metallic materials. Finite-element modelling technique has been used to simulate the transient effects of a moving beam for laser surface heating of metals. The temperature distributions, cooling rates, and thermal gradients have been calculated. Some of the results have been compared with the experimental data.

RISK ASSESSMENT IN TEXTILE AND WOOD, PROCESSING INDUSTRY

The working conditions in textile and wood processing industries have been investigated using a simple risk assessment method and questionnaires worked out for the purpose. A simple/flexible risk assessment method (beginning with a two-stage model that could be enlarged into a six-stage model) is worked out by the authors (Tint & Kiivet) and the implementation possibilities are presented. It is necessary to increase interest from the side of employers for using the method and analyzing the work environment with the aim of improvement implementations. The main complaints in textile industry are high temperature in the workroom, bad ventilation, intense work and the dependence of workers' work results from the others. The main risk factors in wood processing industry are hazardous tools and equipment, also heavy physical load, noise, wood dust and odors of chemicals originating from polishes.

Biodegradation of azo dye C.I. Acid Red 88 by an anoxic–aerobic sequential bioreactor

The potential of a sequential anoxic–aerobic bioreactor to decolorize and degrade azo dye C.I. Acid Red 88 (AR-88) was evaluated. An up flow fixed-film column reactor (UFCR) having polyurethane foam (PUF) as immobilization support was built using a consortium based on four acclimatized bacterial strains belonging to Stenotrophomonas sp., Pseudomonas sp. and Bacillus sp., isolated from waste disposal sites of textile processing industries (TPI) as inoculum. The UFCR was operated at flow rate of 7 mL h −1 with hydraulic retention time (HRT) of 12 h. The effluent of anoxic UFCR was fed to continuously stirred aerobic reactor (CSAR). The sequential anoxic–aerobic treatment of synthetic dye wastewater (SDW) feed having 100 mg L −1 of AR-88 dye resulted in the 98% color and 95% COD removal. The aromatic metabolic intermediates produced under anoxic conditions were transformed to non-aromatic metabolites during aerobic treatment. The UV–visible spectrophotometry, TLC and NMR analyses confirmed the biotransformation of parent dye into unrelated non-aromatic compounds. The azo dye AR-88 was transformed to non-aromatic metabolic intermediates after treatment in sequential anoxic–aerobic bioreactor.

Computational fluid dynamics: A virtual prototyping tool for materials engineering

The use of computational fluid dynamics (CFD) software in many materials processing industries has grown tremendously in recent years. Computational fluid dynamics has been widely utilized for conducting virtual experiments, prototype testing, and parametric studies. Analysis using CFD complements and reduces physical testing, and it can result in a significant time and cost savings. In this article, the application of CFD to a variety of materials-processing problems is presented, with examples taken from the steel, aluminum, glass, semiconductor, and polymer processing fields.

Isolation and characterization of microorganisms capable of decolorizing various triphenylmethane dyes.

Various soil and sludge samples collected from the vicinity of textile dyeing industries and waste disposal sites were used for enrichment of microbial population in the presence of triphenylmethane (TPM) dye Acid Violet-17 (AV-17). Twenty-five (25) isolates were screened for their ability to decolorize AV-17 dye added at a rate of 10 mgl(-1) in mineral salts medium (MSM) agar plates. Five bacterial isolates belonging to Bacillus sp., Alcaligenes sp. and Aeromonas sp. were selected on the basis of their higher decolorization ability and were used to develop a bacterial consortium. The consortium was able to efficiently decolorize various TPM dyes viz. Acid Violet-17 (86%), Acid Blue-15 (85%), Crystal Violet (82%), Malachite Green (82%) and Brilliant Green (85%). The consortium will be further used for designing efficient and cost effective treatment system for effluents of textile processing industries (TPI).

Co-fermentation of Colored Concentrates from the Textile Processing Industry

In the textile processing industry (TPI) inevitable highly loaded organic and/or high colored concentrates arise. A simple way to reduce the freight in the wastewater is to collect and treat these concentrates separately. An almost complete decolorization of many dyes and a digestion of substances, that are refractory under aerobic conditions, can be obtained under anaerobic conditions. Therefore the co-fermentation is an opportune procedure to dispose the concentrates of the TPI in view of ecological, economical, and procedural benefits.

Multiple Use of Water in Industry—The Textile Industry Case

The main aim of this article is to give a review on the state of the art of available processes for the advanced treatment of wastewater from Textile Processing Industry (TPI). After an introduction to the specific wastewater situation of the TPI the article reviews the options of process and production integrated measures. The available unit processes and examples of applied combinations of unit processes are described. A special place is given to the in-plant treatment, the reuse of the treated split flow or mixed wastewater and the recovery of textile auxiliaries and dyes.

Combined chemical and biological treatment of azo dye-containing wastewaters

Wastewaters produced in textile industrial processes contain organic dyes, such as azo dyes, which are not amenable to direct biological treatment. This work examines the possibility of combining ozonation with biological treatment for the effective treatment of wastewaters containing the azo dye Orange II. Oxalate, formate, and benzene-sulfonate are found to be the final products of ozonation. Sulfonated aromatics such as benzene-sulfonate cause organic pollution and are not readily degradable because of their xenobiotic character. For the biological treatment of the ozonation products, activated sludge acclimated to the main product (benzene-sulfonate) was used, and batch experiments under aerobic conditions were performed. On the basis of experimental data, mathematical models describing both processes were developed. An overall mathematical model describing the integrated chemical and biological treatment of the dye was used to estimate the cost of the whole process. The implications of this study for the design of effective dye-containing wastewater treatment plants are discussed.

Computational modelling—a key component in materials processing

Computational analysis software is now widely accepted as a key industrial tool for plant design and process analysis. This is due in part to increased accuracy in the models, larger and faster computer systems and better graphical interfaces that allow easy use of the technology by engineers. The use of computational modelling to test new ideas and analyse current processes helps to take the guesswork out of industrial process design and offers attractive cost savings. An overview of computer-based modelling techniques as applied to the materials processing industry is presented and examples of their application are provided in the contexts of the mixing and refining of lead bullion and the manufacture of lead ingots.

Spatial and temporal regulation of the pesticide dieldrin within industrial catchments

The river catchments of south Yorkshire support a very high density of wool processing industries. Dieldrin was once used as a moth proofing agent, as a sheep dip, and as a pesticide to protect wool fleeces during storage and transport, all of which caused pollution of these catchments due to textile processing. Weekly sampling of four of these rivers revealed two classes of dieldrin contamination: the Aire and Calder (the rivers which support very high concentrations of wool processing industries) had higher concentrations (averaging ∼3 ng/l) than the Don and Trent (∼1 ng/l). The average flux of dieldrin from these rivers into the Humber estuary was 9.8 g/day, with the Aire (of which the Calder is a tributary) and the Trent contributing almost equally, with a smaller contribution from the Don. The Trent has the highest average flow, explaining its large contribution to dieldrin flux. Less detailed sampling of rivers from the north Humber catchment which drain predominantly rural areas had dieldrin concentrations similar to the heavily industrialized southern catchment rivers. This suggests that dieldrin from agronomic and domestic usage may be more persistent than the pollution caused by textile processing industries. Evidence is presented to suggest that the principle dieldrin sources to the Humber catchments are sewage treatment plants, and that the dieldrin sources are in rapid equilibrium with the water column.

Engineered surfaces Part 1.— A philosophy of manufacture

In recent years considerable progress has been made in the characterisation of surface finish in three dimensions, and in the development of protocols which can be used for international standardisation. Although the subject as it has currently developed has much further to go if the process of surface characterisation is to impact on manufacture, control and specification of the manufacturing process itself. Researchers in this important area are beginning to realise that if the subject is to have great impact on manufacturing industries, surface characterisation must be broadened to include measures of surface integrity of the component and in addition be related to the functional demands imposed on the surface. The functional demands being a requirement of the engineering situation in which the components are employed. If these three factors are considered simultaneously, surface characterisation, surface integrity and component function, then a new and important subject is born, the subject of the Engineered Surface. Part 1 of this paper attempts to draw together the elements which go together to create the subject, ‘The Engineered Surface’. The paper presents a method by which this important subject can be developed to the benefit of manufacturing industries. The paper also discusses the importance of a co-ordinated approach to the subject and the way that information can be documented to eventually provide a useful atlas of controlling parameters which are essential for a range of material processing industries as they strive to meet the ever more stringent and cost effective requirements of the manufacture.

How many jobs are for geologists and are there to many students of geology?

On the contrary with general decrease of interest for natural Science and technology studies, matriculation on the Geology department at University of Ljubljana increases. Despite on the increasing number of students the number of graduates remains more or less constant and ranges between 8 and 15 each year. On the Department of Geology 203 students (10,15 per year) graduated in the last 20 years. At this number of students getting bachelors degrees and already employed geologists 1,35-graduate competite for each job in geology. If eveiy employed geologists would be retired today, it would take 14,7 years to replace them. Mentioned employment parameters are quite comparable with those in USA and do not indicate the prevailing opinion of negative trend. The geological qualification in highest de mand by employers (largest number of job vacancies) in the period between 1993 and 1998 was for graduated geological engineers. The number of unemployed with geological qualification is decreasing while in 1998 there was no unemployed geological engineers. The relationship between demand and supplay for geologist reveals possibilities for employment; for geologists with lower qualification the possibility for employment are lower than for geologists with higher qualification. In 1998 the fill in of job vacancies for geologist was in average 70% (100 % for geological engineers, 80 % for geologists with B.D., 80 % for geologists with M. Sc., 25 % for geologist with Ph.D.). In the USA projections for 2006 the largest decrease of employment will occur in mining and raw materials processing industry (-29,49%). In the governmental agencies and organisations the employment will remain stagnate (+0,08%). In the Services the employment will increase (+27,98). In Slovenia similar trends could be expected. In the mining industry employment stoped. Governmental agencies and organisations already have filled up their needs, however employment in local agencies and organisations still remains possible. Geologists in Slovenia are mainly being employed in research Services and education organisations however the ratio of self-employment and employment in holding and investment offices grows up.

Anaerobic treatment of split flow wastewater and concentrates from the textile processing industry

Under anaerobic conditions an almost complete decolorization of many dyes, an efficient COD-removal and a digestion of substances that are refractory under aerobic conditions can be obtained. Therefore anaerobic processes can be used to treat highly loaded split flows and concentrates from the textile processing industry (TPI). Using a large number of biodegradability tests on a bench scale, different types of commercial textile auxiliaries, dyes, real split flow effluents from desizing and dyeing processes and real residual printing pastes were tested in regard to their anaerobic biodegradability. Investigations with anaerobic fixed bed reactors (AFBR) showed that it is possible to treat effluents containing a high organic load from desizing processes and highly coloured effluents from exhaust dyeing processes together resulting in high COD-removal and nearly complete decolorization. With respect to the further aerobic removal of the remaining organic load of the AFBR's effluents it could be seen that the decrease of COD-elimination in AFBR resulting from high portions of effluents from exhaust dyeing processes and short hydraulic retention times is compensated by an increase in aerobic BOD-elimination.

Overview of wastewater treatment and recycling in the textile processing industry

The main aim of this paper is to give a review on the state of the art of available processes for the advanced treatment of wastewater from a Textile Processing Industry (TPI). After an introduction to the specific wastewater situation of the TPI the paper reviews the options of process and production integrated measures. The available unit processes and examples of applied combinations of unit processes are described. A special place is given to the in-plant treatment, the reuse of the treated split flow or mixed wastewater and the recovery of textile auxiliaries and dyes. As a conclusion the paper gives some examples of applied and effective end-of-pipe-steps.