A Review of State-of-the-Art Technologies in Dye-Containing Wastewater Treatment – The Textile Industry Case

Recently, new single or hybrid/combined processes have attracted much attention for treatment of textile and dyeing wastewaters. These processes which may be termed as “state of the art technologies” are membrane separation processes, ultrasonic, photochemical and electrochemical processes. Although the conventional methods still have been tried with some new materials such as, new adsorbents or coagulants, employing the new generation methods such as, electrocagulation-electrooxidation, sonooxidation or photo oxidation are gaining in popularity when the treatment of textile wastewaters is discussed. The purpose of the book chapter is to bring an overview on the new treatment methods for textile wastewaters, one of the most important source of environmental pollution. Despite the fact that there is no uniform standard currently, many countries have legalized some strict discharging standards and scientists and researchers face new technologies including electrical, sonic, magnetic, optical and thermal methods. Although many researches on treatment of synthetic or real wastewaters with various methods are available, very few researches have been carried out on the cutting-edge technologies. Moreover, there are a lot of review article or book chapters on textile wastewater treatment processes individually based on each conventional process such as coagulation, adsorption, chemical oxidation, and biological decolorization. Therefore, in this part of the book, following major and minor titles are stated truly on the aforementioned new technologies. Besides, these parts are not only about cutting-edge technologies, but also related with conventional methods and their new applications in colored wastewater treatment area briefly

Textile Materials in Liquid Filtration Practices: Current Status and Perspectives in Water and Wastewater Treatment

Filtration is considered the keystone of water and wastewater treatment and is used for various purposes, such as sludge dewatering and concentrating any solution. Moreover, as an advanced filtration technology, membranes can remove materials ranging from large visible particles to molecular and ionic chemical species. Proper selection of filter media/membrane material in filtration processes is often the most important consideration for assuring efficient separation. Filter media can be classified by their materials of construction, such as cotton, wool, linen, glass fiber, porous carbon, metals, and rayons. Recently, new polymeric materials have been used both individually and/or blended in filtration processes for the treatment of waters and wastewaters. The purpose of this chapter is to bring an overview on the textile-originated filter materials in filtration applications from conventional filtration to advanced membrane processes. Although many researches on filter media are available, very few researches have been carried out on the cutting-edge technologies about using filter materials on filtration processes from classical to advanced membrane processes. Therefore, in this part of the book, following major and minor titles are stated truly on the aforementioned new technologies and linked with conventional methods in water and wastewater treatment applications

Forward Osmosis Membranes – A Review: Part II

Forward osmosis (FO) is a technical term describing the natural phenomenon of osmosis: the transport of water molecules across a semipermeable membrane by osmotic pressure from a feed solution (FS) to a draw solution (DS). The diluted DS is then reconcentrated to recycle the draw solutes as well as to produce purified water. As the driving force is only the osmotic pressure difference between two solutions, meaning that there is no need to apply an external energy, this results in low fouling propensity of membrane and minimization of irreversible cake forming, which are the main problems controverted by membrane applications, especially in biological treatment systems (e.g., FO membrane bioreactor (FO-MBR)). The purpose of the book chapter is to bring an overview on the FO membrane manufacturing, characterizing and application area at laboratory or full scales. This book chapter is published in two parts. In the second part, which appears here, characterization of mass transport in FO membranes, fouling mechanisms and foulants on FO membranes in naturally asymmetric structure and application areas of FO membranes in the literature are mentioned. Cutting-edge technologies on FO studies are comprehensively reviewed and following major and minor titles are stated truly on the new technologies

Treatment of textile wastewaters by electrocoagulation: technical and economic evaluation

Bu çalışmada, bir tekstil atıksuyunun elektrokoagülasyon (EC) ile arıtılmasının sonuçları ortaya konmuştur. Demir ve alüminyum elektrotlar, monopolar paralel, monopolar seri ve bipolar seri bağlantı şekli ile kullanılmıştır. Arıtma verimliliğinin ölçülmesinde KOİ ve türbidite giderimleri dikkate alınmıştır. KOİ gideriminde, her iki elektrot materyalinde asidik ortam daha uygun olup; demir elektrot için, Bipolar Seri (BP-S) bağlantı şekli etkili olurken, alüminyum elektrotlarda ise her üç bağlantı şekli için birbirine yakın sonuçlar elde edilmiştir. Türbidite gideriminde; optimum pH’nın elektrot materyaline bağlı olduğu, alüminyum elektrotlar için asidik ortamın, demir elektrotlar için ise nötral ortamın daha uygun olduğu tespit edilmiştir. Genel olarak, yüksek akım yoğunluklarının yüksek KOİ ve türbidite giderme verimleri sağladığı görülmüştür. Düşük akım yoğunluğunda (30 A.m-2) demir elektrotlarda sadece Monopolar Paralel (MP-P) sistemden verim alınmıştır. Alüminyum elektrotlarda ise; KOİ giderimi bağlantı şekline göre değişirken, türbidite giderimi bağlantı şeklinden oldukça bağımsızdır. Diğer yandan, EC prosesi alüminyum elektrotlarla daha hızlı ilerlediğinden; her üç bağlantı için de 5 dakikalık bir süre etkili olurken, demir elektrotlarda ise; seri bağlantı sistemleriyle en az 10 dakikalık bir işlem süresine ihtiyaç duyulmakta, MP-P bağlantı şekli ise daha fazla işlem süresi gerektirmektedir. Ekonomik analizde, bir tekstil fabrikasının 1000 m3.gün-1 debide atıksuyunun EC ile arıtılmasının işletme giderleri hesaplanmıştır. Sonuç olarak, bu çalışmada EC prosesinin, kimyasal koagülasyona göre daha az materyal tüketen ve daha az çamur üreten, daha hızlı ve daha ekonomik bir proses olduğu belirlenmiştir. Anahtar kelimeler: Ekonomik analiz, elektrokoagülasyon, elektrot malzemesi, KOİ, tekstil atıksuları, türbidite.Electrocoagulation (EC) is an effective method for wastewater treatment. This paper presents the results of the treatment of a textile wastewater by EC process. Two electrode materials, aluminium and iron, were connected in three modes namely, monopolar-parallel (MP-P), monopolar-serial (MP-S), and bipolar-serial (BP-S). In MP-P mode; anodes and cathodes are in parallel connection, the current is divided between all the electrodes in relation to the resistance of the individual cells. Hence, a lower potential difference is required in parallel connection, when compared with serial connections. In MP-S configuration; each pair of sacrificial electrodes is internally connected with each other, because the cell voltages sum up, a higher potential difference is required for a given current. Otherwise, in BP-S connection; there is no electrical connection between inner electrodes, only the outer electrodes are connected to the power supply. Outer electrodes are monopolar and inner ones are bipolar. This connection mode has simple setup with and has less maintenance cost during operation. The effects of wastewater pH, current density and operating time are presented separately for two sacrificial electrode materials, Fe and Al, and three electrode connection modes mentioned above.  COD and turbidity removals were selected as performance criteria. The following conclusions may be drawn from the experimental results; acidic medium is preferable for a high COD removal for both electrode materials; iron electrode performs clearly better with BP-S mode, while the performance of aluminium is not strongly dependent on connection mode. For a high turbidity removal, the optimum pH depends on the electrode material; aluminium electrode connected in BP-S mode performs better in acidic medium, while the poor filterability of the flocs dictates pH 7 to be more suitable for the iron electrode connected in MP-S mode. High current density is generally favorable for high COD and turbidity removals in the case of iron; at low current density, MP-P mode performs better, while at high current densities, the three modes perform equally well. In the aluminium case, the effect is more pronounced on COD removal and it depends strongly on the connection mode, but it has nearly a negligible effect on the turbidity removal which also unaffected by the connection mode. In the case of aluminium, steady removal efficiencies are reached within 5 min for all three systems, while for iron electrode, serial connection systems, BP-S and MP-S reach steady values in 10 min, while MP-P needs longer operating time. For a complete technical analysis, it is worth to compare EC with conventional chemical coagulation, in regard with removal efficiencies and various important aspects. For this purpose, jar-tests were performed at laboratory scale in order to determine the adequate coagulant dosage. After choosing the best amount, same experiments have been performed to determine optimum pH value for each coagulant. Experimental conditions, removal efficiencies and some other pertinent data of electrocoagulation and chemical coagulation process variations are shown in text. At first sight, it is clearly seen that EC is faster, consumes less material and produces less sludge than chemical coagulation for similar COD and turbidity removal levels. The process using aluminium electrodes connected in MP-S mode seems to be the best choice. Meanwhile, an economic analysis is, of course, needed for a final selection. In economic analysis; the total operation cost was calculated using various experimental dataset such as; energy consumption, sacrificial electrode material, chemicals and sludge amounts per m3 of wastewater for a textile plant with 1000 m3.day-1 of wastewater. Iron is preferred as a low cost one for electrocogulation. On the other hand, FeCl3 is the preferable salt in view of its techno-economic performance for CC. Finally, when EC and CC are compared both technically and economically, the following results may be drawn; the COD removal performance of CC is 10% higher than EC, the turbidity removal is nearly the same, but in 60% longer retention time. With the same initial pH, the final pH is 7.9 in EC, but 2.9 in CC. The final acidic and chloride bearing medium is an important drawback of CC, causing severe corrosion problems which may necessitate high-cost building materials. From this point, Fe2(SO4)3.7H2O may be used despite of its higher operating cost. High coagulant consumption in CC means high chloride concentration in the effluent. Finally, and more importantly, the operating cost of CC is 3.2 times as high as the operating cost of EC. Keywords: COD, economic analysis, electrocoagulation, electrode material, textile wastewaters, turbidity

Microplastic in the environment: identification, occurrencand mitigation measures

Microplastic is an emerging pollutant causing trouble worldwide due to its extensive distribution and potential hazards to the ecological system. Some fundamental questions about micro-plastics, such as their presence, source, and possible hazards, remain unanswered. These issues develop because of a lack of systematic and comprehensive microplastic analysis. As a result, we thoroughly evaluated current knowledge on microplastics, including detection, characterization, occurrence, source, and potential harm. Microplastics are found in seawater, soil, wetlands, and air matrices worldwide based on findings. Visual classification, which can be enhanced by com-bining it with additional tools, is one of the most used methods for identifying microplastics. As soon as is practicable, microplastics analytical methods ought to be standardized. New techniques for analyzing nano-plastics are urgently needed in the meantime. Numerous studies have shown that microplastics’ impacts on people and soil are significantly influenced by their size, shape, and surface physicochemical characteristics. Finally, this study suggests areas for future research based on the knowledge gaps in the area of microplastics. © 2022 Desalination Publications. All rights reserved

Advances In Hydrogen Generation Technologies

Among energy sources, hydrogen gas is clean and renewable and has the potential to solve the growing energy crisis in today's society because of its high-energy density and noncarbon fuel properties. It is also used for many potential applications in nonpolluting vehicles, fuel cells, home heating systems, and aircraft. In addition, using hydrogen as an energy carrier is a long-term option to reduce carbon dioxide emissions worldwide by obtaining high-value hydrocarbons through the hydrogenation of carbon dioxide. This book presents the recent progresses and developments in water-splitting processes as well as other hydrogen generation technologies with challenges and future perspectives from the point of energy sustainability

Water and Wastewater Treatment

The use of water, one of the most valuable and vital resources in the world, should respond to growing needs, and used water should not have negative effects on the environment. Research on the reduction of used water and wastewater quantities, post-use treatment, or reuse/recovery methods is increasing day by day. These studies focus on finding the most appropriate method from both technical and economic perspectives. In this book, emerging technologies and materials used in the treatment, reuse, or recovery of various kinds of water and wastewaters are examined. The book consists of valuable scientific research specifically including desalination and use of renewable energy, nanomaterials, biosorbents, photocatalytic treatment, as well as riverbank filtration and wetlands. The editor would like to record his sincere thanks to the authors for their contributions