சுற்றுச்சூழல் & பகுப்பாய்வு நச்சுயியல்

The current use and shift from fossil fuels to renewable resources is not the only reason for adopting alternative energy resources. Certain rural communities lack the access to the available resources, due to multiple factors: proximity, technical-skill, access, off-grid systems and socio-economic factors. Even though the most frequently sort out renewable system for electrification is solar energy, particularly for temperate climates with vast abundance and high solar radiation. The contribution of solar energy harnessed using photovoltaic panels has been significantly beneficial to remote areas off-grid with no access to main grid system; other challenges encountered are varied, depending on the project outcome. Some of which are cost optimization and storage units. The demand and supply side response for electrification has largely been determined by the prevailing market rate. A demand side response (DSR) approach is applied to tackle this challenge, this determines the current energy requirements of the community and identifies the optimal hybrid system with or without storage. For this analysis, two systems scenarios were modelled: (1) PV with Diesel Generator System and (2) PV with Battery Storage System. In each system four photovoltaic panels (PV) sizes which were chosen, tested and analysed for optimal sizing. The PV sizes were 0.4 kW, 0.6 kW, 0.8 kW and 1 kW. The optimization between these sizes was built based on three main objectives – (a) Energy Demand Satisfaction /Demand Side Response (b) System Cost and (c) pollution. In both system scenarios, the optimal size was the 1 kW with battery storage and 1 kW with diesel generator. A further comparative analysis was carried out between the two systems; when the diesel generator is used and when the battery is applied. Both scenarios can sufficiently meet the demand without any considerable interruption, but disparities exist between them in relation to cost and technical optimization. A highly significant difference in the costs between the two system scenarios were detected. The total cost in PV-Battery system represents only 26% of the PV system. Also, the PV and Battery system does not release any harmful emissions compared with nearly 6 tCO2 /year in the PV with Diesel system.

In the present study, the levels of selected heavy metals (Cr, Cd, Mn, Cu, Zn, and Pb) were determined using Flame Atomic Absorption Spectrophotometeric method. The following concentration ranges (mg/L) were recorded in wastewater samples: Cr (2.006-373.005), Cd (0.015-0.051), Mn (1.421-3.049), Cu (0.024-0.906) and Zn (0.105-0.934). Whereas, Pb was found to be blow detection limit (0.04). The concentration of Cr was highest followed by Mn in all sample sites and these values were found to be significantly higher than the maximum permissible limits of WHO, NEQS and FEPA. The levels of Cd, Cu and Zn were within the maximum permissible limits for effluent discharged into rivers. Decreasing in concentrations of heavy metals with distance from point source up to a distance of 40 meters was observed. pH, Temperature (°C), COD, TDS, TSS, SO42- and Cl- (mg/L) were also determined: Temperature (24.65-25.52), pH (8.85-10.31), SO42- (22.74-695.77), TDS (1500.00-4300.00), TSS (1505.00-2498.33), Cl- (235.03-1396.29) and COD (512.39-902.50). Similarly, anion concentration decreased with distance from point source up to a distance of 40 m. The control sample which is 40 m far before the wastewater inter into the Dufa River, recorded the lowest concentrations for all the parameters under studied. A statistical analysis of variance (ANOVA) at 95% confidence level shows that, there is a statistical significance variation of means concentration between the four sampling sites except pH and temperature.

Polyaromatic air pollution is a serious environmental issue in the modern world due to the high carcinogenicity and geno-toxicity of these pollutants to the all-living beings. These pollutant concentrations in the air are being increased day by day due to huge vehicular emissions, oil refining processes and other industrial processes spread among urbanized areas. Gas or particle bounded PAHs in the air deposit on ground level through wet deposition or dry deposition. These pollutants deposition mainly on plants other than many exposing surfaces spread among the earth. Therefore, the plant leaves highly abundant in urban areas rich with these deposited pollutants. All plant leaves are great niches for microorganisms which is called phyllosphere. Phyllosphere of plants consists with many phyllosphere microorganisms belong to different group of bacteria, fungi, algea and protozoa. Among them bacteria are the predominant phyllosphere microorganisms. The phyllosphere bacteria highly abundant in polluted areas have special capability to degrade polyaromatic hydrocarbons. These PAH degrading phyllophere microorganisms can be used to clean the polluted air, this is called phylloremediation. Phylloremediation is an effective bioremediation method which can use to remediate the air, water and soil polluted from the PAH compounds. The aim of this review is to discuss polyaromatic hydrocarbonic air pollution and deposition of these chemicals on phyllosphere. High depositions of PAHs on plant leaves created harsh conditions to the inhabiting bacterial population in this phyllosphere and their ability to degrade PAH compounds are discussed. Then possibilities of usage of phylloremediation to clean the polluted air from the PAH compounds are discussed.