Supriya Sarkar

Anionically functionalized guar gum embedded with silica nanoparticles: An efficient nanocomposite adsorbent for rapid adsorptive removal of toxic cationic dyes and metal ions

In the present work, a novel biodegradable nanocomposite has been developed (h-GG/SiO2) based on anionically modified guar gum and in-situ deposited SiO2 NPs through sol-gel technique. Here the anionically modified guar gum stimulates the silica polymerization process and hence acts as a unique template for the development of spherical SiO2 NPs. Batch adsorption studies indicate that h-GG/SiO2 nanocomposite shows remarkable adsorption capacity for cationic dyes/metal ions (Qmax: 781.25mgg-1for malachite green (MG), 281.69mgg-1 for safranin (SF); 645.16mgg-1 for Pb2+, 709.21mgg-1 for Cd2+) as well as it efficiently and selectively removes cationic MG from mixture of dye solutions. Finally the worthy regenerative efficacy of h-GG/SiO2 facilitates the adsorbent to be economically promising for practical application in the field of wastewater management.

Phytoremediation of industrial mines wastewater using water hyacinth

ABSTRACT The wastewater at Sukinda chromite mines (SCM) area of Orissa (India) showed high levels of toxic hexavalent chromium (Cr VI). Wastewater from chromium-contaminated mines exhibit potential threats for biotic community in the vicinity. The aim of the present investigation is to develop a suitable phytoremediation technology for the effective removal of toxic hexavalent chromium from mines wastewater. A water hyacinth species Eichhornia crassipes was chosen to remediate the problem of Cr (VI) pollution from wastewater. It has been observed that this plant was able to remove 99.5% Cr (VI) of the processed water of SCM in 15 days. This aquatic plant not only removed hexavalent Cr, but is also capable of reducing total dissolved solids (TDS), biological oxygen demand (BOD), chemical oxygen demand (COD), and other elements of water also. Large-scale experiment was also performed using 100 L of water from SCM and the same removal efficiency was achieved.

Phytoremediation Potential of Duckweed (Lemna minor L.) On Steel Wastewater

An eco-friendly and cost effective technique- phytoremediation was used to remediate contaminants from waste water. This study demonstrated that phytoremediation ability of duckweed (Lemna minor L.) to remove chloride, sulphate from Biological Oxygen Treatment (BOT) waste water of coke oven plant. The BOT water quality was assessed by analyzing physico-biochemical characters – pH, Biological oxygen demand (BOD), Chemical oxygen demand (COD), total dissolved solids (TDS) and elemental concentration. It was observed that an increase in pH value indicated an improvement of water quality. The experimental results showed that, duckweed effectively removed 30% chloride, 16% sulphate and 14% TDS from BOT waste water, which suggested its ability in phytoremediation for removal of chloride and sulphate from BOT waste water. A maximum increase of 30% relative growth rate of duckweed was achieved after 21 days of experiment. Thus, it was concluded that duckweed, an aquatic plant, can be considered for treatment of the effluent discharged from the coke oven plant.

Integrated treatment of GCP and slag quenching water of LD steel making unit

The scarcity of water has driven every steel plant in India to pursue major water conservation initiatives. R&D Tata Steel Jamshedpur has invented an integrated and cost effective process for treatment and reuse of steel making gas cleaning plant (GCP) wastewater and Linz-Donawitz (LD) slag quenching (SQ) wastewater. The new treatment process consists of mixing of GCP water with SQ wastewater in a specific ratio followed by coagulant addition and controlled carbon dioxide (CO2) sparging. The average total suspended solid (TSS) and total dissolve solids (TDS) concentration of treated water were observed to be 22 and 190 mg L−1 during 180 days of continuous monitoring. Thus the water quality falls well within the limits for reuse and recycle standards within the plants. The maximum allowable limit of TDS and TSS for industrial water supplies is 500 and 100 ppm, respectively. The process significantly reduces the water requirement for steel making and paves the path for conversion of LD steel making process into a sustainable ‘Zero Liquid Discharge’ unit.

Bioremediation of steel plant wastewater and enhanced electricity generation in microbial desalination cell

Microbial desalination cell (MDC) is a propitious technology towards water desalination by utilizing wastewater as an energy source. In this study, a multi-chambered MDC was used to bioremediate steel plant wastewater using the same wastewater as a fuel for anodic bacteria. A pure culture of Pseudomonas putida MTCC 1194 was isolated and inoculated to remove toxic phenol. Three different inoculum conditions, namely P. putida (INC-A), a mixture of P. putida and activated sludge (INC-B), and activated sludge alone (INC-C) were employed in an anodic chamber to mainly compare the electricity generation and phenol degradation in MDCs. The study revealed the maximum phenol removal of 82 ± 2.4%, total dissolved solids (TDS) removal of 68 ± 1.5%, and power generation of 10.2 mW/m2 using INC-B. The synergistic interactions between microorganisms, can enhance the toxic phenol degradation and also electricity generation in MDC for onsite wastewater application.

Industrial Wastewater Treatment Using Phycoremediation Technologies and Co-Production of Value-Added Products

Algae are a diverse group of photosynthetic organisms with profound bioremediation potential and industrial applications that can reduce the cost of expenditure on energy and fuels. Algae have been applied to various applications from fuels and medicines to wastewater treatment. Potential applications of phycoremediation have instigated laboratories to reinforce the development of algal-based technologies for better exploitation of their bioremediation potential and by-product generation ability. Many species of algae have been studied and utilized for their function in wastewater treatment. Certain technological drawbacks need to be addressed to manage the shortcomings of algae for industrial usage. This review mainly focuses on the state of the art applications of phycotechnology for wastewater remediation. Many problems related to algal technology have also been exemplified and discussed such as contamination, decreasing the resilience time and increasing the biomass of the algal culture. Possible solutions of these bottlenecks have been suggested to better apply phycotechnology for wastewater remediation in industries considering the environmental issues. Recently, the concept of genetic engineering is found very useful that has increased the potential of phycotechnology reducing the resilience time considerably. On the contrary, the negative impact of the algal-based technologies on the environment and economy has also been deliberated in order to effectively utilize and manage this important organism with utmost benefit. Lastly, the review illuminates the scope and options of future research in the area of phycoremediation technologies.

Microbial Degradation of Coal into a Value Added Product

ABSTRACT Microbial treatment has been considered as an economic, effective and environment safe way of processing coal via degradation of the macromolecular network into simpler, low molecular weight products. The present work is intended to observe the feasibility of microbial attack on reject coal, having high ash content (65% ash). The results indicated that microorganisms were able to change and modify the macro molecular structure of reject coal. This paper summarizes the potential ability of the microorganisms to beneficiate reject coal and to make a value-added product, humic acid from reject coal. This work describes the status of current and the probable directions of the future research.

Modification of UASB reactor by using CFD simulations for enhanced treatment of municipal sewage

Up-flow anaerobic sludge blanket (UASB) has been in use since last few decades for the treatment of organic wastewaters. However, the performance of UASB reactor is quite low for treatment of low strength wastewaters (LSWs) due to less biogas production leading to poor mixing. In the present research work, a modification was done in the design of UASB to improve mixing of reactor liquid which is important to enhance the reactor performance. The modified UASB (MUASB) reactor was designed by providing a slanted baffle along the height of the reactor having an angle of 5.7° with the vertical wall. A two-dimensional computational fluid dynamics (CFD) simulation of three phase gas-liquid-solid flow in MUASB reactor was performed and compared with conventional UASB reactor. The CFD study indicated better mixing in terms of vorticity magnitude in MUASB reactor as compared to conventional UASB, which was reflected in the reactor performance. The performance of MUASB was compared with conventional UASB reactor for the onsite treatment of domestic sewage as LSW. Around 16% higher total chemical oxygen demand removal efficiency was observed in MUASB reactor as compared to conventional UASB during this study. Therefore, this MUASB model demonstrates a qualitative relationship between mixing and performance during the treatment of LSW. From the study, it seems that MUASB holds promise for field applications.

Current and Future Trends Toward Reduction of CO 2 Emission from Steel Industries

Carbon dioxide is the major greenhouse gas in the environment. Its largest contributor is fossil fuel based industries and among them steel industry holds one of the vital positions. In view of global climate change agreements, there are efforts to reduce CO2 emission by development of suitable technologies. In last decades, various technologies have been developed to separate CO2 from the flue gas of power and industrial plants by using chemical or physical absorption, adsorption, cryogenic methods, membrane systems and biological fixation, etc. This paper elaborates on the aspects of different carbon capture processes and sequestration technologies developed and adopted by steel industries. In many cases, pilot scale studies have been completed successfully and are ready for implementation. Though, further development and fine tuning is required for commercialization of such processes.

Role of Modelling in the Development of High Performance Steels for Important Engineering Applications

Stainless steels of different types and grades are being developed world over to meet ever increasing demand for enhanced materials performance. Advanced stainless steel products have applications in a variety of industries including nuclear, defence, space, chemical, oil and gas, medical and appliance. It is understood that the properties of the alloys strongly depend not only on the chemical composition but also on their microstructure, which in turn depends on parameters in the manufacturing process. Therefore, the challenge to the manufacturing industry is not only selection of optimum composition but also relevant manufacturing processes to meet the requirements. Designing a manufacturing process and optimum process schedules using experimental trials is both time consuming and expensive. Modeling and simulation play an important role to reduce these times effectively. This paper presents important points to be considered to produce clean steels and highlights the applicability of modeling techniques that can be effectively applied in a manufacturing industry. Some of the case studies that are included in the paper are Computational Fluid Dynamics model to understand gas atomisation Finite element modeling of compound tube extrusion In conclusion, the power of modeling and simulation to understand manufacturing processes is highlighted.