Srimanta Ray

Evaluation of Physiochemical characteristics of disposed Rubber industry effluent: A Case study of Bodhjungnagar Industrial Growth Centre

The suitable agro-climate conditions are making the Tripura State into second largest rubber producer in country, India. Rapid growth of rubber production and rubber based industries has resulted rapid economy growth of the State. Despite the derived economy benefit, the rubber based industry generates large quantities of effluents during the various stages of processing. The production process of commercial rubber products causes serious water pollution problems. Massive disposal of effluents in to inland water surface often causes damage to the precious water resources. Surface water resources are the greatest victims due to effluent of rubber processing industries. The present study is aimed to quantify the trend of deterioration of water quality within the study area and its resulting impacts on the surface water resources due to inland disposal of effluent from the rubber based industries of Bodhjungnagar Industrial Growth Centre. Major causes of deterioration of water quality are due to high BOD load, high concentration of suspended solid and nitrogen content. Different extents of acid usage in various sections of rubber processing industries are also responsible for pH variation and causing acidic effluent. Such a study is an attempt to redress the water pollution problem in the Bodhjungnagar Industrial Growth Centre.

Role of Biocathodes in Bioelectrochemical Systems

Environmental damage, depleting fossil fuels and energy security are major factors driving intensive research efforts to develop carbon neutral or carbon negative technologies which can be used to produce electricity and chemicals. Technologies under development to achieve this goal include those based on bioelectrochemical, biological, thermal and chemical processes. Evolving technologies employing biological as well as electrochemical principles are grouped in the bioelectrochemical systems (BESs) category. The main focus of this chapter is on biocathodes used in BESs.

Enhanced TiO 2 nanorods photocatalysts with partially reduced graphene oxide for degrading aqueous hazardous pollutants

Enhanced TiO2 nanorods (TNRs) with partially reduced graphene oxide (RGO) (designated as GT) were prepared for degrading aqueous hazardous pollutants. The degree of RGO oxidation had an important role in affecting the photoelectronic and photocatalytic activities of GT composites. The study examined the impact of the degree of RGO oxidation on the photocatalytic activities. The photocatalytic activity of the materials was investigated for degrading rhodamine b (RhB), methyl orange (MO), methylene blue (MB), and phenol by using ultraviolet (UV) light. The highest photocatalytic activity was observed when the atomic oxygen-to-carbon (O/C) ratio of RGO was 0.130 ± 0.003. This study suggested the photocatalytic performance was maximized by preserving a selected amount of the RGO oxygen-containing groups. The work reported in this study on optimizing the RGO-based TiO2 photocatalyst could serve as a promising approach for preparing and optimizing other types of carbon-based photocatalysts such as graphene-based CdS.

A Study on Utilization of Latex Processing Effluent for Treatment and Energy Recovery in Microbial Fuel Cell

The incremental discharge of organic waste has been of great environmental concern due to stringent environmental regulation and increased cost of waste treatment. Microbial degradation of waste is a conventional treatment route but harvesting energy from organic waste employing microbial route in microbial fuel cell (MFC) has generated considerable interest in recent years. Thus MFC presents a potential route for treatment and simultaneous energy recovery from organic waste. The present study is focused in that direction and is aimed at treatment of the latex processing effluent (LPE) with concurrent energy recovery. LPE is marked as pollutant due to high organic load, acidity and nitrogen content. LPE is of great environmental concern for north-eastern states of India and Tripura in particular, since Tripura is the second largest latex producer in India and around 25 L of effluent is produced per kilogram of latex processed. The present study fabricated a two-chambered MFC from low cost materials without membrane separator and monitored the degradation of LPE. 80 % degradation of substrate (LPE) was recorded in 18 days with 40 % total nitrogen removal. The MFC generated around 700 mV potential in open circuit condition. The maximum current generated was 0.083 A/m2 and the net power output was 64 mW/m2 of electrode area. Thus, the present study demonstrated the treatment of LPE in a low cost membrane-less MFC with concurrent energy recovery and thereby presents a sustainable utilization route of a problematic effluent, like LPE, using MFC.

A Study on Simultaneous Photocatalytic Removal of Hexavalent Chromium and Pharmaceutical Contaminant from Aqueous Phase

Chromium (Cr) as Cr(+VI) is a well known environmental pollutant being highly toxic to most organisms including humans and are difficult to remove. Pharmaceuticals have also become a cause of environmental concern in recent years. Photocatalysis has emerged as a potential technology for treating variety of environmental pollutants and has gathered research interest in recent years for removing Cr(+VI). Among the reported photocatalysts titanium dioxide (TiO2) and zinc oxide (ZnO) had been widely studied due to high bandgap energy. However, the potential of ZnO as photocatalyst in the removal of Cr(+VI) is less explored. Studies also reported that presence of iron (Fe) ions and sacrificial organic electron donor greatly influence the photocatalytic removal of Cr(+VI). Accordingly the present study evaluated the efficacy of ZnO and Fe-impregnated ZnO (Fe–ZnO) in photocatalytic removal of Cr(+VI) with a model pharmaceutical compound, methylene blue (MB), as sacrificial electron donor under solar radiation. Fe incorporated ZnO was fabricated and X-ray diffraction (XRD) confirmed thet Fe penetrated into the ZnO lattice. The incorporation of Fe in ZnO resulted in shift in bandgap energy and allowed better utilization of solar radiation. Fe incorporation and presence of organic electron donor (MB) enhanced the Cr (+VI) in comparison to ZnO. Also, increase in catalyst loading enhanced the photo-reduction of Cr (+VI). A maximum of 48 % reduction of Cr(+VI) was recorded with 98 % MB discoloration with Fe-ZnO in 4 h of exposure in solar radiation. The present work demonstrates an alternative approach wherein two different toxic and problematic waste was simultaneously remediate in a sustainable manner.

Sizing of a grid independent hybrid energy system using a power reliability approach

Hybrid energy system (HES) is an excellent solution for electrification of remote rural areas where the grid extension is difficult and not reliable. Thus the present study analyzes different HES in terms of power supply reliability for a remotely located model site having an average electricity demand of 35.4 kW. Solar photovoltaic (PV) arrays, diesel generators (DG) and batteries (BAT) are the components chosen for the HES considering the practical constraints. The reliability of power supply is evaluated based on loss of power supply probability (LPSP) for various system architectures. Thus the systematic approach of optimizing the utilization of power sources in terms of reliability of power supply is the unique feature of the present study.

Cost Optimization of a Hybrid Off-Grid Power System for Remote Localities: A Statistical Model

Renewable energy sources like solar radiation, wind energy, geothermal energy, bioenergy are known to well integrate with off-grid stand-alone power systems. The choice of a renewable energy source depends on the geographical location and climatic condition of the region, available resources, and the economics of the power system. Thus, the evaluation and optimization of hybrid power systems in terms of cost of energy (CoE) with various alternative energy sources considering the demand of the location and available resources is highly pertinent for configuring a hybrid power system for remote localities. The present work describes a case study on development of a response surface (RS) model for predicting the optimum CoE of a hybrid off-grid power system (HOPS). RS model is developed using Box–Behnken experimental design (BBD) technique. A three-factor three-level BBD is used to describe the optimum CoE. The three process variables under consideration in BBD model are size of photovoltaic arrays (PV), diesel generator (DG) capacity, and number of battery (BAT) cells. The analysis of variance (ANOVA) is conducted on the response (CoE) for each factor level settings of a three-factor three-level BBD in order to evaluate a full quadratic factor space. The results of ANOVA established significant linear, quadratic, and interaction terms in the RS model representing the factor space. The coefficients of the RS-model are determined using multiple regression analysis technique at 95 % level of confidence. The RS-model is checked for error in prediction by residual analysis technique and validated against experimental data to confirm the accuracy of the model. The results confirmed that the model has 97.5 % accuracy in prediction of CoE for a HOPS. The RS-model is also allowed to identify the optimal configuration of hybrid power system for minimum CoE. A minimum CoE predicted by the model is comparable with that reported in the literature from earlier studies. The model presented in this study can be a useful tool for cost comparison among similar architectures of varying capacities for HOPS.