Surface-active Agents in Textile Processes and their Effect on Effluents

Various types of surface-active agent and their applications in textile processing are reviewed. In choosing a product for a particular application, the user must consider many factors, such as the biodegradability of the agent and its subsequent influence on effluents, waste treatment, and water pollution. A very wide choice of branded products is currently available, but approximately 95 % of the materials are based on a limited number of organic chemicals, the most important of which are the ethylene oxide condensates of alkylphenols and straight-chain alcohols, secondary alkyl sulphates, the alkylbenzenesulphonates (both branched- and straight-chain), and the primary alcohol sulphates. The biodegradability of these materials is discussed in relation to their chemical structures. Many of the surface-active materials now in use are biologically degradable. However, many non-ionic agents are biologically hard. Considerable attention is being focused on them since, at very low concentrations, they have a synergistic effect on the foaming of surface waters when traces of anionic detergents are present. Desirably, these biologically hard materials should be replaced by materials that do not have objectionable properties with regard to water purity. When new biodegradable products are being developed full consideration should also be given to their applicational characteristics.     

Removing colour from dyehouse waste waters — a critical review of technology available

Strict controls are being introduced on coloured effluents from UK dyehouses discharged to sewer. Failure to comply with these new regulations could result in prosecution. Yet in certain cases the technology to treat dyehouse waste waters adequately is either not available or prohibitively costly. This paper (originally given at a conference at the Manchester Conference Centre entitled ‘Waste water management for industry’) reviews the treatment technologies that can currently be used by the textile processor and discusses those newer techniques that may emerge in the near future.     

Contributions of electrochemical oxidation to waste‐water treatment: fundamentals and review of applications

OVERVIEW: This paper provides an overview of some fundamental aspects of electrochemical oxidation and gives updated information on the application of this technology to waste‐water treatment. In recent years, electrochemical oxidation has gained increasing interest due to its outstanding technical characteristics for eliminating a wide variety of pollutants normally present in waste‐waters such as refractory organic matter, nitrogen species and microorganisms. IMPACT: The strict disposal limits and health quality standards set by legislation may be met by applying electrochemical oxidation. However, treatment costs have to be cut down before full‐scale application of this technology. Deployment of electrochemical oxidation in combination with other technologies and the use of renewable sources to power this process are two steps in this direction. APPLICATIONS: Effluents from landfill and a wide diversity of industrial effluents including the agro‐industry, chemical, textile, tannery and food industry, have been effectively treated by this technology. Its high efficiency together with its disinfection capabilities makes electro‐oxidation a suitable technology for water reuse programs. Copyright © 2009 Society of Chemical Industry     

Anaerobic treatment of textile effluents: A review

The treatment of textile waste water is commonly carried out using biological (mainly aerobic) and physico-chemical systems. However, anaerobic bioreactors can be used to at least partially treat these effluents and provide a number of significant advantages. The most attractive feature for the treatment of textile effluents is the decolourisation of many dyes under the reducing conditions present in an anaerobic reactor. Laboratory-scale results on this particular topic are here reviewed. A second major advantage of anaerobic processing is its ability to treat wastestreams with high organic loads such as the effluents from the desizing and scouring operations currently employed in the textile manufacturing industry. Reports on successful, full-scale and pilot-scale plants are also reviewed and some limitations are discussed. © 1998 Society of Chemical Industry     

Water Pollution and Control

The demand for clean water for industry and for domestic supply is increasing yearly. Many readily accessible supplies are fuh'y exploited and water authorities are now having to consider hitherto-polluted rivers as possible sources for future demand. To meet the demand for clean water and for cleaner rivers which receive the waste from the consumers, a massive amount of expenditure will be required from central and local government and from industry for new water-treatment plants. The legislation covering river pollution and waste-water disposal in Scotland is described, and the particular problem of effluents from the textile industry is discussed. Many workers have demonstrated that waste water from the textile industry can be treated using conventional biological treatment and other techniques and be purified sufficiently to meet the standards imposed by the local authority for discharge into the sewerage system, or by the river purification board for discharge into the rivers or the sea.     

电镀废水化学综合处理

某五金电镀厂改造后日排废水总量为250m∧3。根据厂方提供的水质水量情况,结合国家的废水排放标准,设计中对氰、铬、镍及酸碱废水采取分流排放,分而治之,简述了工艺设计原则、工艺流程原理、处理方法及调试运行中的一些故障排除。     

中山市城市污泥与印染污泥处置对策研究

至今中山市已建成20座城市污水处理厂，分布于中山市的各个镇区，生活污水处理规模为75．5万t，d：中山市的纺织印染行业发达，印染洗水行业产生的废水经处理后产生大量的印染污泥。由于目前中山市内的污水处理厂和绝大多数印染洗水企业均未配套污泥处置设施，大量的市政污泥和印染污泥未经无害化处理，需要转移至市外进行处置，甚至出现污泥不规范地倾倒填埋现象，成为危害城乡环境的二次污染物。因此，市政污泥和印染污泥处置已成为当前中山市环境保护的一项十分重要而又紧迫的任务。     

染整前处理绿色助剂及新型前处理工艺

在纺织品的染色前处理、染色、后处理阶段,由于必须使用大量的助剂和洗涤工序,产生大量的废水。在新世纪,人们越来越关心环境保护,因此,有关纺织品的各个处理阶段的环保型助剂研发和采用环保型新工艺成为纺织印染行业的重要任务。同时,还就染色前处理的绿色助剂和绿色工艺进行讨论。     

Waste Water Treatment in the Oil Industry

Due to the fact that effluents from oil industry contribute to pollution of our environment very much, they must pass a purification process. This paper presents a purification proposal for waste water originating from an oil and vegetable fat producing process. This proposal is given after laboratory investigations made by a flotation apparatus. Tables include the most important parameters before and after the treatment, on which basis the efficiency of the used process is determined. When separating all kinds of impurities from water a removing effect between 50 and 100 % can be achieved.     

Photocatalytic reactors for environmental remediation: a review

Research in the field of photocatalytic reactors in the past three decades has been an area of extensive and diverse activity with an extensive range of suspended and fixed film photocatalyst configurations being reported. The key considerations for photocatalytic reactors, however, remain the same; effective mass transfer of pollutants to the photocatalyst surface and effective deployments and illumination of the photocatalyst. Photocatalytic reactors have the potential versatility to be applied to the remediation of a range of water and gaseous effluents. Furthermore they have also been applied to the treatment of potable waters. The scale‐up of photocatalytic reactors for waste and potable water treatment plants has also been demonstrated. Systems for the reduction of carbon dioxide to fuel products have also been reported. This paper considers the main photocatalytic reactor configurations that have been reported to date. Copyright © 2011 Society of Chemical Industry     

Biological treatment of waste water in the compact reactorDie biologische Reinigung von Abwässern im kompaktreaktor

A newly developed loop reactor has been shown to treat various domestic and industrial waste waters highly efficiently. In pilot studies BOD₅ capacities per unit volume as high as 28 kg m^?3 d^?1 have been achieved for domestic waste water. In treating the effluents from a paper factory the compact reactor gives the same degree of conversion for only 1/6 of the residence time of the factory's conventional effluent treatment plant.     

SEMIPERMEABLE MEMBRANE DEVICE-AVAILABILITY OF POLYCYCLIC AROMATIC HYDROCARBONS IN RIVER WATERS AND WASTEWATER TREATMENT PLANT EFFLUENTS

River waters and wastewater treatment plant effluents contain hydrophobic organic compounds (HOCs) such as polycyclic aromatic hydrocarbons (PAHs) which are persistent, bioaccumulative, and dangerous for the environment. The biological risk assessment of HOCs requires the estimation of their bioavailable fraction in addition to the total contamination of the media. The bioavailability of HOCs depends on the characteristics of the aquatic environments. In particular, the presence of organic matter (OM) usually reduces the bioavailability of HOCs by trapping them and preventing them from crossing biological membranes. The semipermeable membrane device (SPMD) technique is used to evaluate bioavailable fractions of HOCs. We tested the influence of aquatic and more particularly OM characteristics on the SPMD-availability of PAHs, in several river waters (up and downstream a large town) and in wastewater treatment plant effluents. Thirteen priority PAHs were analyzed in total water and in SPMDs. Aquatic environments were characterized for their pH, ionic strength, temperature, chlorophyll A, and suspended solids contents. Total and dissolved OMs were characterized for aromaticity, biodegradability, molecular weight, and hydrophobicity. The total PAH contamination increased downstream the river; wastewater effluents were proven to be a source of SPMD-available PAHs. We attempted to establish relationships between the characteristics of organic matter and the SPMD-availability in order to initiate an aquatic environment typology: The SPMD-availability was negatively related to dissolved OM molecular weight and aromaticity, and positively related to biodegradability.     

Decolorisation of aqueous dye solutions by low‐cost adsorbents: a review

Effluent generated by the textile industry can be highly coloured. Before the waste is disposed into receiving waters, colour removal is an important consideration. Because of their complex molecular structures, dyes present in the textile wastewater are not removed easily by conventional wastewater treatment processes. They are fairly stable to light, as well as heat, and resist biodegradation, thus posing a challenge to conventional physico‐chemical and biological treatment methods. Although adsorption technology using activated carbon has been considered to be an effective and proven technology, it has its limitations as it is expensive and necessitates regeneration. As cost is an important consideration in most developing countries, efforts have been made to explore the possibility of using various low‐cost alternatives that are biodegradable, abundant, readily available, and are derived from waste materials. This article is a compilation of the investigations carried out by numerous researchers (from 2002 onwards) on the effective use of different kinds of low‐cost adsorbents for the removal of specific dyes from textile wastewater.     

Recent developments of metal oxide semiconductors as photocatalysts in advanced oxidation processes (AOPs) for treatment of dye waste‐water

The textile industry presents a global pollution problem owing to the dumping or accidental discharge of dye waste‐water into waterways, which is having a major impact on the quality and aesthetics of water resources. The World Bank estimates that 17 to 20% of industrial water pollution comes from textile dyeing and treatment. This percentage represents an appalling environmental challenge for clothing designers and other textile manufacturers. Recently, the application of metal oxide semiconductors in the advanced oxidation process (AOP) has gained wide interest for the treatment of dye waste‐water owing to its good degradation efficiency, low toxicity and physical and chemical properties. AOP refers to a set of chemical treatment procedures designed to remove organic and inorganic materials from waste‐water by oxidation. In this paper, recently developed metal oxide semiconductors are discussed, in which the semiconductors are generally divided into three categories: (i) titanium dioxide; (ii) zinc oxide; and (iii) other metal oxides (such as vanadium oxide, tungsten oxide, molybdenum oxide, indium oxide and cerium oxide). The syntheses and modification methods as well as the efficiency of each category are discussed and analyzed. Copyright © 2011 Society of Chemical Industry     

Highly Thermal-Resistant and Biodegradable Textile Sizes from Glycols Modified Soy Proteins for Remediation of Textile Effluents

Poly(vinyl alcohol) (PVA) sizes are widely used in textile industry due to their excellent sizing properties on synthetic fibers and their blends. However, PVA contains non-biodegradable chemicals and is a major contributor to environmental pollution related to the textile industry. To overcome this problem, an environmental-benign and highly thermal-resistant yarn coating is fabricated from soy proteins, an agricultural byproduct. The soy proteins are chemically modified by glycols having varying chain lengths and number of hydroxyl groups. Compared with the physically modified soy proteins and their sized yarns, coating made from the soy proteins esterified by 1,4-butanediol show 91.38% increment in work of rupture at 120 °C and cotton/polyester (65/35) yarns sized by 1,4-butanediol esterified soy protein sizes have 39.91% decrease in coefficient of friction. In addition, 1,4-butanediol esterified soy sizes have a five-day biochemical oxygen demand/chemical oxygen demand of 0.476, indicating that the chemically modified soy sizes have high biodegradability in activated sludge. Successful utilization of modified soy sizes can promote large-quantity applications of soy byproducts, impelling high value addition to agricultural byproducts and sustainability of textile industry.     

The use of membranes for the recycling of water and chemicals from dyehouse effluents: an economic assessment

The practical and economic feasibility of using membrance technology to recycle/reuse dyes and their associated proces waters and auxiliary chemicals from dyebath effluent in and textile plants is assessed. Factors affecting the practicality of recycling dyes include: the type of process used to dye the fabric, classes of the dye used, the effluent volume, the frequency with which the dye is used and the auxiliary chemicals added to the dyebath during the dyeing process. These considerations also apply to the suitability of recycling the process water associated with the dye. Other factors to consider include the water quality required for recycling and the stage of the process to which this water can be reintroduced. To assess the economics of dyebath effluent reuse, water company treatment and supply charges, and dye and chemical costs must be considered. Data from five textile dyehouses are presented.     

Water network synthesis in refinery

Minimizing fresh raw water and wastewater effluent produced by industry has rigorously been studied over the past two to three decades. However, most studies have focused on rather theoretical illustration with little consideration of technical constraints in industry. Furthermore, use of massive industry data significantly increases the complexity of the problem, and no research paper has covered such a case study with practical solutions. This paper reviews the latest technology of water network synthesis and its applications, and provides a detailed guideline of the whole study procedure with a reference to case study based from refinery complex. Two main methodologies of water-pinch technology and a mathematical optimization programming are reviewed individually, and they are applied to a case study. Economic and operational constraints are embedded into optimization of water network synthesis in order to provide more reliable and achievable solutions for the minimization of fresh water consumption and reduction of waste water effluents. This generic approach can be similarly applied to other industries such as petroleum, steel, and paper manufacturing.     

Intensification of the bio‐processing of cotton textiles by combined enzyme/ultrasound treatment

Utilization of highly specific enzymes for various textile‐processing applications is becoming increasingly popular because of their ability to replace harsh organic/inorganic chemicals currently used by the textile industry. Thus, a significant decrease in the amount and toxicity of textile wastewater effluents is achievable. It was established that ultrasound does not inactivate the complex structures of enzyme molecules and as a consequence there was significant improvement in the performance of both cellulase and pectinase enzymes. The experimental data indicate that the maximum benefit provided by sonication occurs at relatively low enzyme concentrations. Ultrasonic energy significantly intensified enzymatic activity on various types of cotton fabrics, but it did not contribute to a decrease in tensile strength. The combined enzyme/sonication treatment of cellulosic textiles offers significant advantages such as less consumption of expensive enzymes, shorter processing time, less fiber damage and better uniformity of treatment. Published in 2002 for SCI by John Wiley & Sons, Ltd     

Application of Ozone in Textile Wastewater Treatment

Textile wastewaters are known to be highly resistant to biodegradation under both natural and wastewater treatment plant conditions. However, ozonation can be used to increase the biodegradability of the biologically resistant compounds. The combined method of ozonation and subsequent biodegradation of both synthetic and real textile wastes was explored in laboratory-scale studies. Two kinds of industrial wastes were simulated for effluents from dyehouse and washing machines. Upon determining the ozonation conditions of synthetic wastes, the real industrial wastes were investigated. The real textile wastewater was taken from textile factories, located in ód? , Poland, from subsequent stages of textile processing; dyeing, washing, rinsing and from an equalizer tank. Ozonation was carried out in a lab-scale bubble column sparged reactor, while the biological degradation proceeded in a trickle bed biofilter.     

光催化臭氧法对化工制药废水的解毒和降解研究

采用光催化臭氧法(O_3/UV)对某化工制药高浓度毒性废水进行生化系统前的预处理的实验研究,考察了臭氧气体流量对有机物降解影响、O_3/UV对废水可生化性的影响。实验结果表明:光催化臭氧法(O_3/UV)对含有杀菌剂等的高浓度有毒化工制药废水的解毒效果明显,可明显提高废水的可生化性(BOD_5/COD)。