Satish K. Lokhande

Stress-induced lipids are unsuitable as a direct biodiesel feedstock: a case study with Chlorella pyrenoidosa.

The effects of various stresses on the suitability of lipid synthesized by Chlorella pyrenoidosa for biodiesel production were investigated. Lipids were characterized for detailed fatty acid methyl ester profiling and biodiesel properties like cetane number (CN), iodine value, cold filter plugging point (CFPP). Maximum biomass productivity (106.63 mgL(-1)d(-1)) and lipid content (29.68%) were obtained at indoor cultivation (nitrate sufficient, pH 8-10, 24h illumination). However, compared to this condition, other nitrate sufficient cultures [pH 6-8 and 10-12 (24h illumination), and at ambient CO2 and 16:8h light:dark photoperiod (pH unadjusted)] showed ∼12-14% lower lipid productivity. Upon 50% nitrate depletion (at indoor and outdoor; pH unadjusted) lipid content has increased by 7.62% and 17%, respectively. Though stress conditions helped enhancing lipid accumulation, there was two-fold increase in PUFA content compared to that observed at pH 8-10. This resulted in fuel properties which did not comply with the biodiesel standards.

Biomethanation of vegetable market waste in an anaerobic baffled reactor: Effect of effluent recirculation and carbon mass balance analysis.

In the present study, feasibility of biomethanation of vegetable market waste in a 4-chambered anaerobic baffled reactor (ABR) was investigated at 30d hydraulic retention time and organic loading rate of 0.5gVS/L/d for one year. Indicators of process stability viz., butyrate/acetate and propionate/acetate ratios were consistent with phase separation in the different chambers, which remained unaltered even during recirculation of effluent. Chemical oxygen demand (COD) and volatile solids (VS) removal efficiencies were observed to be consistently high (above 90%). Corresponding biogas and methane yields of 0.7-0.8L/g VS added/d and 0.42-52L/g VS added/d respectively were among the highest reported in case of AD of vegetable waste in an ABR. Process efficiency of the ABR for vegetable waste methanation, which is indicated by carbon recovery factor showed that, nearly 96.7% of the input carbon considered for mass balance was accounted for in the product.

Treatment of refractory nano-filtration reject from a tannery using Pd-catalyzed wet air oxidation

We attempted catalytic wet air oxidation (CWAO) of nanofiltration (NF)-reject using Pd based catalyst viz., Pd/activated charcoal (AC) and PdCl2 with the objective of degradation of refractory organic pollutants. Refractory organic pollutants in NF-reject before and after WAO and CWAO were confirmed by GC-MS analysis. Experiments were conducted to investigate the effects of temperature, catalyst dosage and air partial pressure on the rate of removal of total organic carbon (TOC). The reaction kinetics can be conveniently described by considering two-stage first order kinetics. The use of Pd/AC afforded 85% TOC removal, the corresponding rate constant (k) was 2.90 ± 0.075 × 10(-3)min(-1) (Pd/AC, 100mg/L; T, 473.15K; Pair, 0.69 MPa). On the other hand, 75% TOC was removed with k=2.31 ± 0.075 × 10(-3)min(-1) using Pd(2+) catalyst (Pd(2+), 16.66 mg/L; T, 473.15K; Pair, 0.69 MPa). The observed rate of mineralization under Pd-catalyzed conditions was significantly higher than that of the uncatalyzed oxidation (41%) under the similar experimental conditions. Catalyst stability experiments were performed and TEM, SEM, XRD, Raman and XPS characterization data collected. Despite some morphological transformation of support, Pd catalyst was stable under CWAO conditions.

Ozone-Induced Biodegradability Enhancement and Color Reduction of a Complex Pharmaceutical Effluent

The treatment of a complex pharmaceutical effluent using a combination of ozonation and biological treatment is reported with the use of ozonation as a pre- and posttreatment. Pretreatment facilitated biodegradability index (BI = BOD/COD) enhancement of up to 0.44 along with COD and color reduction of up to 42% and 33%, respectively. Subsequent anaerobic biodegradation of effluent indicated negligible biogas generation; however, aerobic biodegradation of pretreated effluent resulted in COD reduction (73%) and color reduction (62%), which was also indicated by the biokinetic parameters. Further, ozonation as a posttreatment led to higher overall COD (87%) and color (93%) removal.

Assessment and Prediction of Environmental Noise Generated by Road Traffic in Nagpur City, India

The main intention of research is to quantify and predict the noise level due to heterogeneous traffic conditions at critical junctions and highways. A study was carried out to assess the existing status of noise levels and its impacts on the environment with a possibility of further expansion of the city. Vehicular traffic noise levels measured during peak and non-peak hours at all selected locations were higher (71–76 dBA and 69.3–76.3 dBA) than the prescribed limits. The recognized amount of traffic and with the help of road geometry data, prediction of noise level is performed using modified Federal Highway Administration (FHWA) model, and the computed noise was compared with the measured one for assuring the relevance of this model for prediction of forthcoming noise. The outcome received from this model was nearer to the observed noise level, having a percentage error of ±3%, the best fit lines generated between them gives R 2 of 0.457. In this study measured and computed noise exposure levels were depicted with the help of contour maps. Octave band spectral analysis reveals that the interrupted traffic flow is above the free flow traffic and realized that the contribution of two wheeler and cars/jeep are mainly responsible for a generation of noise level at both the lower and higher frequencies, it also signifies that the FHWA model is convenient to be used for Indian circumstances.

Time-Dependent Study of Electromagnetic Field and Indoor Meteorological Parameters in Individual Working Environment

Human beings in modern society are facing wide-range of electromagnetic (EMF) radiations from few hertz (Hz) to gigahertz (GHz) range. Its minor sources are power supply, personal computers, Wi-Fi routers, Zig-bee, cell phones and base trans-receiver stations (BTS) devices. We have extensively used them in microenvironments like offices, restaurants, buses, close auditorium, etc. In such indoor environments, the air quality incorporates various gaseous emissions, temperature, humidity, particulate matters, etc. Accordingly, the cumulative effect of EMF and air-quality parameters can change human health and quality of life. This paper described exposure assessment of EMF and indoor meteorological parameters in the individual microenvironment during working and non-working hours. The results were obtained via broadband methodology for assessment of EMR and point source methodology for temperature, relative humidity and particulate matter (PM). The kriging model in surfer software approved to be more suitable to show accurate gridding of EMF during working and non-working hours. No significant change observed in time-dependent analysis of EMF, temperature, humidity and PM count. However, telephony band was dominant during whole analysis. Hence, more investigations are required to identify the quantitative relation between these independent parameters.

Realizing modeling and mapping tools to study the upsurge of noise pollution as a result of open-cast mining and transportation activities

Introduction: In open-cast mines, noise pollution has become a serious concern due to the extreme use of heavy earth moving machinery (HEMM). Materials and Methods: This study is focused to measure and assess the effects of the existing noise levels of major operational mines in the Keonjhar, Sundergadh, and Mayurbhanj districts of Odisha, India. The transportation noise levels were also considered in this study, which was predicted using the modified Federal Highway Administration (FHWA) model. Result and Discussion: It was observed that noise induced by HEMM such as rock breakers, jackhammers, dumpers, and excavators, blasting noise in the mining terrain, as well as associated transportation noise became a major source of annoyance to the habitants living in proximity to the mines. The noise produced by mechanized mining operations was observed between 74.3 and 115.2 dB(A), and its impact on residential areas was observed between 49.4 and 58.9 dB(A). In addition, the noise contour maps of sound level dispersion were demonstrated with the utilization of advanced noise prediction software tools for better understanding. Conclusion: Finally, the predicted values at residential zone and traffic noise are correlated with observed values, and the coefficient of determination, R2, was calculated to be 0.6891 and 0.5967, respectively.

Assessment of Heterogeneous Road Traffic Noise in Nagpur

The objective of the study is to assess the noise scenario and evaluate prediction model for heterogeneous traffic conditions. In the past few years, road traffic of Nagpur has increased significantly due to the rapid increase in the number of vehicles. Noise levels are monitored at six different squares, characterized as interrupted traffic flow due to traffic signals, high population density and heavy traffic where the major sources of noise are engines, exhausts, tires interacting with the road, horns, sound of gear boxes, breaks, etc. The A-weighted time-average sound levels (LAeq;T) are measured at the different time of day during peak and off-peak traffic hours. To assess the traffic noise more precisely, the noise descriptors such as L10, L50, L90, LAeq;T, TNI (Traffic Noise Index), NPL (Noise Pollution Level) and NC (Noise Climate) are used. In the present study, the Federal Highway Administration (FHWA) noise prediction model is used for prediction of noise levels and it is observed that one-hour duration measured LAeq;T ranged from 71 to 76 dB(A) and 71.6 to 76.3 dB(A) during peak and off peak hours respectively. Due to the heavy traffic the peak hour Sound Exposure Levels (LAE) at all locations are exceeding permissible limit of 70 dB(A) prescribed by the World Health Organization (W.H.O). Off-peak traffic hour noise levels are within permissible limit except at two locations, Jagnade and HB town square. Significant correlation was obtained when best fit lines generated between measured and predicted values gives R2 of 0.455 for all time intervals. Chi-Square test (χ2) was also computed to investigate the noise levels at different squares. The results show that the inhabitants of Nagpur city are exposed to high transportation noise during daytime.

Understanding carbon regulation in aquatic systems - Bacteriophages as a model

The bacteria and their phages are the most abundant constituents of the aquatic environment, and so represent an ideal model for studying carbon regulation in an aquatic system. The microbe-mediated interconversion of bioavailable organic carbon (OC) into dissolved organic carbon (DOC) by the microbial carbon pump (MCP) has been suggested to have the potential to revolutionize our view of carbon sequestration. It is estimated that DOC is the largest pool of organic matter in the ocean and, though a major component of the global carbon cycle, its source is not yet well understood. A key element of the carbon cycle is the microbial conversion of DOC into inedible forms. The primary aim of this study is to understand the phage conversion from organic to inorganic carbon during phage-host interactions. Time studies of phage-host interactions under controlled conditions reveal their impact on the total carbon content of the samples and their interconversion of organic and inorganic carbon compared to control samples. A total organic carbon (TOC) analysis showed an increase in inorganic carbon content by 15-25 percent in samples with bacteria and phage compared to samples with bacteria alone. Compared to control samples, the increase in inorganic carbon content was 60-70-fold in samples with bacteria and phage, and 50-55-fold for samples with bacteria alone. This study indicates the potential impact of phages in regulating the carbon cycle of aquatic systems.