Amal Raj - Academia.edu (original) (raw)

Papers by Amal Raj

Research paper thumbnail of A new Fuzzy-LOGIC based Model for Chlorophyll-a in Pulicat Lagoon, India

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Research paper thumbnail of Influence of the sediment composition, total organic carbon on the distribution of benthic organisms at Pulicat lagoon

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Research paper thumbnail of Biodegradation of direct golden yellow, a textile dye by Pseudomonas putida

Desalination and water treatment

In this study, biodecolorization of Direct golden yellow dye using a bacterial strain Pseudomonas... more In this study, biodecolorization of Direct golden yellow dye using a bacterial strain Pseudomonas putida was investigated. Laboratory scale experiments were performed to investigate the effect of operational parameters such as pH, dye concentration and dissolved oxygen on the decolorization effi ciency of the strain. The most effi cient decolorization was achieved in the pH range of 7−9 and the biodecolorization process was found to be effective under static and anoxic conditions but aeration strongly inhibited the decolorization. In decolorization, the maximal absorption wavelength in the UV-visible spectra for the dye containing culture shifted from visible light range towards the ultraviolet visible range confi rming the structural modifi cations of the dye molecule during the course of degradation. The strain also exhibited excellent stability during the reported batch experiments. It has been observed that there is an induction of reductase enzyme (azo-reductase), which helps in the anaerobic reduction of azo bonds present in the dye structure. The cells obtained from the late-stationary phase exhibited high azoreductase activity than the cells from exponential and early-stationary phase. Hence the study reveals the potential of P. putida to degrade Direct golden yellow dye effectively under static conditions.

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Research paper thumbnail of Carlson’s Index, a poor cursor of trophic status assessment of Pulicat Lagoon, southeast coast of India

International Journal of Environmental Studies

Pulicat Lagoon is a productive coastal lagoon on the southeast coast of India. Several studies of... more Pulicat Lagoon is a productive coastal lagoon on the southeast coast of India. Several studies of its physico‐chemical and biological characteristics have been undertaken. This project was the first to attempt to represent the lagoon’s ecological status in the form of a trophic state index. The investigation applied Carlson’s Trophic State Index (TSI) to determine the trophic status of Pulicat

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Research paper thumbnail of Comparison of the performance of two indices of trophic status for depicting the status of Pulicat lagoon ecosystem

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Research paper thumbnail of Nitrification of synthetic wastewater in a cross flow medium trickling filter

Bioprocess and Biosystems Engineering

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Research paper thumbnail of A NEW LOGIC-BASED MODEL TO PREDICT NITRATES IN GROUNDWATER USING ARTIFICIAL NEURAL NETWORK (ANN)

ABSTRACT n this study, a soft computing technique using Artificial Neural Network (ANN) has been ... more ABSTRACT n this study, a soft computing technique using Artificial Neural Network (ANN) has been used to model the nitrate concentration which is an important indicator of the groundwater quality. Using an algorithm construct in the MATLAB modelling environment, a final ANN model was developed by methodical screening of the different ANN architectures produced for the cases under study. Further, the model was validated using the data on the groundwater quality of Ayapakkam, in Thiruvallur near Chennai City, Tamilnadu, India for the prediction of nitrate concentration. The correlation between the observed and predicted values of the nitrate concentrations were found to be very high (r = 0.998). The results of the model exhibit an accuracy of 99% (RMSE = 0.053 and Index of agreement = 0.992) in predicting the final nitrate concentration which underscores the efficiency of the model for the current study.

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Research paper thumbnail of Selection of Suitable Ecosystem Indicators as Tools to Assess the Ecosystem Health of Coastal Lagoons and Their Implications in Management

ABSTRACT In recent years, coastal lagoons have been recognized for their significance as producti... more ABSTRACT In recent years, coastal lagoons have been recognized for their significance as productive ecosystems as well as for their important roles in maintaining ecological balance. However, for understanding the structure and functioning of coastal lagoons for preserving their natural quality one has to take into account the rapid degradation of these unique ecosystems. Hence, tools for indicating rapid changes in lagoon ecosystems in order to assess and maintain their health are the needs of the hour. Ecological indicators available to ecosystem managers for this purpose are numerous and often inappropriately selected within the context of lagoon management. Thus it is important to select suitable ecosystem indicators to accurately determine the status of the lagoon ecosystems. This article provides a comprehensive review of the existing ecosystem indicators used in the monitoring of lakes and lagoons. Further, it explores the functionalities of these indicators and correlates them with their applicability in conservation and management of a coastal lagoon. The purpose of this work is to provide a chart of reference for managers of coastal lagoons for easy and suitable selection of ecosystem indicators as tools for use in a cogent environmental monitoring programme.

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Research paper thumbnail of Performance of sulfonated polystyrene–ethylene–butylene–polystyrene membrane in microbial fuel cell for bioelectricity production

Journal of Power Sources

ABSTRACT Proton exchange membranes (PEMs) are an essential component for studying microbial fuel ... more ABSTRACT Proton exchange membranes (PEMs) are an essential component for studying microbial fuel cells (MFCs), in spite of certain limitations and high operational cost. Present study reports the performance of a sulfonated polystyrene–ethylene–butylene–polystyrene (SPSEBS) membrane for application in MFCs. SPSEBS produces 106.9% higher power density and low internal resistance than Nafion 117® in a single chamber MFC (SCMFC). The oxygen mass transfer coefficient (KO) is one order lesser in SPSEBS than in Nafion 117 thereby reducing substrate loss while increasing coulombic efficiency (CE). SPSEBS maintains a low pH gradient between the anode and cathode resulting in high performance. The change in the solution conductivities for Nafion is also much greater than that of SPSEBS. The results of this study indicate that SPSEBS could be a suitable PEM for improving the efficiency of MFCs.

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Research paper thumbnail of Considerations on ecosystem modelling and management in the context of World Lake Vision using a case study of Chilika Lagoon

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Research paper thumbnail of Modelling of Chlorophyll-A Concentrations in Pulicat Lagoon , Southeast Coast of India Using Artificial Neural Network

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Research paper thumbnail of Synthetic dairy wastewater treatment using cross flow medium trickling filter

Journal of Environmental Science and Health Part A

ABSTRACT The treatment of synthetic dairy wastewater was carried out using cross flow medium tric... more ABSTRACT The treatment of synthetic dairy wastewater was carried out using cross flow medium trickling filter of specific surface area 243 m/m. The operating variables in this study were hydraulic and organic loading rates. The hydraulic loadings employed in this study were 5, 9, 13 and 17 m/m.d for the influent COD concentrations of 427 to 1384 mg/l. It was observed that the relationship between organic removal rate and organic loading rate showed two regions of linear behaviour with the point of inflection at an organic loading rate of 26 g COD/m.d. Kornegay model was used to evaluate the kinetic coefficients for the system. The results were found to be satisfactory.

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Research paper thumbnail of Predictive Capability of Three Empirical Models in Estimating the Chlorophyll: A Comparative Case Study of Pulicat Ecosystem

ABSTRACT The primary productivity of a coastal lagoon can be inferred from the data on the concen... more ABSTRACT The primary productivity of a coastal lagoon can be inferred from the data on the concentration of the primary photosynthetic pigment, chlorophyll-a in phytoplankton. Being the essential macronutrient limiting the growth of phytoplankton, the concentration of primary nutrients such as phosphorus and nitrate in their dissolved states can be related to the concentration of chlorophyll-a in the water. Thus it is possible to determine the trophic status of a lagoon through predicted values of chlorophyll-a obtained by using the empirical relationship between the phytopigment and its limiting nutrient. In the present study, three empirical models developed by Dillon and Rigler (1974), Rast and Lee (1978) and Bartsch and Gakstatter (1978) relating the concentrations to inorganic phosphate to chlorophyll-a have been investigated for their capability to predict the concentrations of the phytopigment at Pulicat lagoon in the Southeast coast of India. The results obtained from the study have been used to describe the trophic status of a coastal lagoon in the southeast coast of India, namely, Pulicat lagoon ecosystem. The results obtained suggest that there are large discrepancies in the values obtained from these models and those obtained from analysis of the samples. From the present study model performance is influenced by the non-linear relationships between the nutrient concentration and the production of phytopigment, chlorophyll-a varying over different seasons and years.

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Research paper thumbnail of An Interactive Spatial Model of Pulicat Lagoon Using Geographic Information System

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Research paper thumbnail of Carbon oxidation and nitrification of dairy wastewater in a trickling filter

Journal of Environmental Science and Health Part A

In this investigation a single stage cross flow medium trickling filter was used to study the com... more In this investigation a single stage cross flow medium trickling filter was used to study the combined carbon oxidation and nitrification of synthetic dairy wastewater. The synthetic dairy wastewater was prepared to have influent TKN concentration of 30, 60 and 90 mg/1 at various COD concentrations (30–298 mg/1). The effect of organic loading rate on TKN removal was studied for three different hydraulic loading rates of 5,9 and 13 m/m.d. Within an organic loading rate of 0.39 kg COD/md the TKN removal efficiency was observed to be more than 60%. The TKN removal percent showed a decreasing trend with increase in COD/TKN ratio. For organic load greater than 1.39 kg COD/m.d the nitrate production was completely eliminated.

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Research paper thumbnail of Application of Fuzzy Indices to determine the trophic status of Pulicat Lagoon, Southeast Coast of India

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Research paper thumbnail of Comparison of the trickling filter models for the treatment of synthetic dairy wastewater

Bioprocess and Biosystems Engineering

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Research paper thumbnail of Performance of upflow anaerobic filter in the treatment of distillery spentwash

Distillery spentwash, owing to its high COD, BOD along with obnoxious odour and dark colour prese... more Distillery spentwash, owing to its high COD, BOD along with obnoxious odour and dark colour presents several operational challenges when applying biological treatment technologies. Conventional treatment techniques achieve only about 70% COD removal, with the treated effluent still exceeding the limits prescribed by the Pollution Control Board. Hence, the need of the hour is an efficient technology to reduce the polluting capacity of the distillery wastes. Keeping this in mind, an investigation using a laboratory-scale upflow anaerobic filter (UAF) to study carbonaceous removal of distillery spentwash under mesophilic conditions has been attempted. The effect of hydraulic loadings on COD removal has been evaluated at different COD concentrations ranging from 2000 to 13000 mg/L. The COD removal percentage during the period of investigation was found to be in the range of 54.8% to 88.7%. The biogas yield was observed to be in the range of 0.33-0.45 m3/kg of COD destroyed.

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Research paper thumbnail of A new Fuzzy-LOGIC based Model for Chlorophyll-a in Pulicat Lagoon, India

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Influence of the sediment composition, total organic carbon on the distribution of benthic organisms at Pulicat lagoon

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Biodegradation of direct golden yellow, a textile dye by Pseudomonas putida

Desalination and water treatment

In this study, biodecolorization of Direct golden yellow dye using a bacterial strain Pseudomonas... more In this study, biodecolorization of Direct golden yellow dye using a bacterial strain Pseudomonas putida was investigated. Laboratory scale experiments were performed to investigate the effect of operational parameters such as pH, dye concentration and dissolved oxygen on the decolorization effi ciency of the strain. The most effi cient decolorization was achieved in the pH range of 7−9 and the biodecolorization process was found to be effective under static and anoxic conditions but aeration strongly inhibited the decolorization. In decolorization, the maximal absorption wavelength in the UV-visible spectra for the dye containing culture shifted from visible light range towards the ultraviolet visible range confi rming the structural modifi cations of the dye molecule during the course of degradation. The strain also exhibited excellent stability during the reported batch experiments. It has been observed that there is an induction of reductase enzyme (azo-reductase), which helps in the anaerobic reduction of azo bonds present in the dye structure. The cells obtained from the late-stationary phase exhibited high azoreductase activity than the cells from exponential and early-stationary phase. Hence the study reveals the potential of P. putida to degrade Direct golden yellow dye effectively under static conditions.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Carlson’s Index, a poor cursor of trophic status assessment of Pulicat Lagoon, southeast coast of India

International Journal of Environmental Studies

Pulicat Lagoon is a productive coastal lagoon on the southeast coast of India. Several studies of... more Pulicat Lagoon is a productive coastal lagoon on the southeast coast of India. Several studies of its physico‐chemical and biological characteristics have been undertaken. This project was the first to attempt to represent the lagoon’s ecological status in the form of a trophic state index. The investigation applied Carlson’s Trophic State Index (TSI) to determine the trophic status of Pulicat

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Research paper thumbnail of Comparison of the performance of two indices of trophic status for depicting the status of Pulicat lagoon ecosystem

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Nitrification of synthetic wastewater in a cross flow medium trickling filter

Bioprocess and Biosystems Engineering

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Research paper thumbnail of A NEW LOGIC-BASED MODEL TO PREDICT NITRATES IN GROUNDWATER USING ARTIFICIAL NEURAL NETWORK (ANN)

ABSTRACT n this study, a soft computing technique using Artificial Neural Network (ANN) has been ... more ABSTRACT n this study, a soft computing technique using Artificial Neural Network (ANN) has been used to model the nitrate concentration which is an important indicator of the groundwater quality. Using an algorithm construct in the MATLAB modelling environment, a final ANN model was developed by methodical screening of the different ANN architectures produced for the cases under study. Further, the model was validated using the data on the groundwater quality of Ayapakkam, in Thiruvallur near Chennai City, Tamilnadu, India for the prediction of nitrate concentration. The correlation between the observed and predicted values of the nitrate concentrations were found to be very high (r = 0.998). The results of the model exhibit an accuracy of 99% (RMSE = 0.053 and Index of agreement = 0.992) in predicting the final nitrate concentration which underscores the efficiency of the model for the current study.

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Research paper thumbnail of Selection of Suitable Ecosystem Indicators as Tools to Assess the Ecosystem Health of Coastal Lagoons and Their Implications in Management

ABSTRACT In recent years, coastal lagoons have been recognized for their significance as producti... more ABSTRACT In recent years, coastal lagoons have been recognized for their significance as productive ecosystems as well as for their important roles in maintaining ecological balance. However, for understanding the structure and functioning of coastal lagoons for preserving their natural quality one has to take into account the rapid degradation of these unique ecosystems. Hence, tools for indicating rapid changes in lagoon ecosystems in order to assess and maintain their health are the needs of the hour. Ecological indicators available to ecosystem managers for this purpose are numerous and often inappropriately selected within the context of lagoon management. Thus it is important to select suitable ecosystem indicators to accurately determine the status of the lagoon ecosystems. This article provides a comprehensive review of the existing ecosystem indicators used in the monitoring of lakes and lagoons. Further, it explores the functionalities of these indicators and correlates them with their applicability in conservation and management of a coastal lagoon. The purpose of this work is to provide a chart of reference for managers of coastal lagoons for easy and suitable selection of ecosystem indicators as tools for use in a cogent environmental monitoring programme.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Performance of sulfonated polystyrene–ethylene–butylene–polystyrene membrane in microbial fuel cell for bioelectricity production

Journal of Power Sources

ABSTRACT Proton exchange membranes (PEMs) are an essential component for studying microbial fuel ... more ABSTRACT Proton exchange membranes (PEMs) are an essential component for studying microbial fuel cells (MFCs), in spite of certain limitations and high operational cost. Present study reports the performance of a sulfonated polystyrene–ethylene–butylene–polystyrene (SPSEBS) membrane for application in MFCs. SPSEBS produces 106.9% higher power density and low internal resistance than Nafion 117® in a single chamber MFC (SCMFC). The oxygen mass transfer coefficient (KO) is one order lesser in SPSEBS than in Nafion 117 thereby reducing substrate loss while increasing coulombic efficiency (CE). SPSEBS maintains a low pH gradient between the anode and cathode resulting in high performance. The change in the solution conductivities for Nafion is also much greater than that of SPSEBS. The results of this study indicate that SPSEBS could be a suitable PEM for improving the efficiency of MFCs.

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Research paper thumbnail of Considerations on ecosystem modelling and management in the context of World Lake Vision using a case study of Chilika Lagoon

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Modelling of Chlorophyll-A Concentrations in Pulicat Lagoon , Southeast Coast of India Using Artificial Neural Network

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Synthetic dairy wastewater treatment using cross flow medium trickling filter

Journal of Environmental Science and Health Part A

ABSTRACT The treatment of synthetic dairy wastewater was carried out using cross flow medium tric... more ABSTRACT The treatment of synthetic dairy wastewater was carried out using cross flow medium trickling filter of specific surface area 243 m/m. The operating variables in this study were hydraulic and organic loading rates. The hydraulic loadings employed in this study were 5, 9, 13 and 17 m/m.d for the influent COD concentrations of 427 to 1384 mg/l. It was observed that the relationship between organic removal rate and organic loading rate showed two regions of linear behaviour with the point of inflection at an organic loading rate of 26 g COD/m.d. Kornegay model was used to evaluate the kinetic coefficients for the system. The results were found to be satisfactory.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Predictive Capability of Three Empirical Models in Estimating the Chlorophyll: A Comparative Case Study of Pulicat Ecosystem

ABSTRACT The primary productivity of a coastal lagoon can be inferred from the data on the concen... more ABSTRACT The primary productivity of a coastal lagoon can be inferred from the data on the concentration of the primary photosynthetic pigment, chlorophyll-a in phytoplankton. Being the essential macronutrient limiting the growth of phytoplankton, the concentration of primary nutrients such as phosphorus and nitrate in their dissolved states can be related to the concentration of chlorophyll-a in the water. Thus it is possible to determine the trophic status of a lagoon through predicted values of chlorophyll-a obtained by using the empirical relationship between the phytopigment and its limiting nutrient. In the present study, three empirical models developed by Dillon and Rigler (1974), Rast and Lee (1978) and Bartsch and Gakstatter (1978) relating the concentrations to inorganic phosphate to chlorophyll-a have been investigated for their capability to predict the concentrations of the phytopigment at Pulicat lagoon in the Southeast coast of India. The results obtained from the study have been used to describe the trophic status of a coastal lagoon in the southeast coast of India, namely, Pulicat lagoon ecosystem. The results obtained suggest that there are large discrepancies in the values obtained from these models and those obtained from analysis of the samples. From the present study model performance is influenced by the non-linear relationships between the nutrient concentration and the production of phytopigment, chlorophyll-a varying over different seasons and years.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of An Interactive Spatial Model of Pulicat Lagoon Using Geographic Information System

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Carbon oxidation and nitrification of dairy wastewater in a trickling filter

Journal of Environmental Science and Health Part A

In this investigation a single stage cross flow medium trickling filter was used to study the com... more In this investigation a single stage cross flow medium trickling filter was used to study the combined carbon oxidation and nitrification of synthetic dairy wastewater. The synthetic dairy wastewater was prepared to have influent TKN concentration of 30, 60 and 90 mg/1 at various COD concentrations (30–298 mg/1). The effect of organic loading rate on TKN removal was studied for three different hydraulic loading rates of 5,9 and 13 m/m.d. Within an organic loading rate of 0.39 kg COD/md the TKN removal efficiency was observed to be more than 60%. The TKN removal percent showed a decreasing trend with increase in COD/TKN ratio. For organic load greater than 1.39 kg COD/m.d the nitrate production was completely eliminated.

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Research paper thumbnail of Application of Fuzzy Indices to determine the trophic status of Pulicat Lagoon, Southeast Coast of India

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Comparison of the trickling filter models for the treatment of synthetic dairy wastewater

Bioprocess and Biosystems Engineering

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Research paper thumbnail of Performance of upflow anaerobic filter in the treatment of distillery spentwash

Distillery spentwash, owing to its high COD, BOD along with obnoxious odour and dark colour prese... more Distillery spentwash, owing to its high COD, BOD along with obnoxious odour and dark colour presents several operational challenges when applying biological treatment technologies. Conventional treatment techniques achieve only about 70% COD removal, with the treated effluent still exceeding the limits prescribed by the Pollution Control Board. Hence, the need of the hour is an efficient technology to reduce the polluting capacity of the distillery wastes. Keeping this in mind, an investigation using a laboratory-scale upflow anaerobic filter (UAF) to study carbonaceous removal of distillery spentwash under mesophilic conditions has been attempted. The effect of hydraulic loadings on COD removal has been evaluated at different COD concentrations ranging from 2000 to 13000 mg/L. The COD removal percentage during the period of investigation was found to be in the range of 54.8% to 88.7%. The biogas yield was observed to be in the range of 0.33-0.45 m3/kg of COD destroyed.

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