Current Issue : July - September Volume : 2014 Issue Number : 3 Articles : 7 Articles
The study reports the analysis and measurement of the noise levels of CNG refueling Stations and\nPower Generators of Power Development Board (PDB) induced noise pollution in Sylhet City. For this\npurpose noise levels have been measured at ten major locations of the city for CNG refueling Stations\nand in PDB, Kumargaon. Sound levels are measured at different location at different time interval for\nthe respective study locations with the help of a standard Sound meter. It was found that the noise\nlevels for both study locations are much higher that exceed the allowable permissible noise limits. The\nstudy suggests that noise path must be controlled by using appropriate sound barriers that can reflect\nand diffuse noise appropriately and particularly use of sound enclosure can reduce noise level...
Flood is a recurring event that leads to hazards. The probability of a flood occurring is normally\ninvestigated followed by flood hazard mapping which defines the areas that are at risk of flood inundation.\nThis study carries out flood hazard assessment for the flood prone areas within the low-lying flat river\nvalley of the River Dep watershed using Remote Sensing (RS) and geographic information system (GIS) for\n2-year to 1000-year return periods, with regards to inhabited areas and other land uses that will be affected.\nResult shows that the most affected land use within the floodplain is agriculture with inundated area\nranging from 68.82 to 146.10 km2. Low to medium flood hazards predominant dominate the floodplain with\narea extent increasing from 112.2 to 140.75 km2 for low hazard and 35.65 to 163.65 km2 for medium hazard.\nHigh hazard is mainly within the deep part of the floodplain with minimal area extent of 4.11 km2. The study\nrecommends low hazard areas to be used for irrigation farming and early rainy season farming, medium and\nhigh hazard areas for irrigation farming only while low, medium and high hazard areas for the 100-year flood\nshould be avoided with respect to construction of residential or commercial structures. Generally areas\nclose to rivers should be avoided for rainy season farming and residential or commercial development....
The aim was to measure the concentrations of heavy metals in groundwater obtained from 30 randomly\nselected domestic wells and 10 stream locations all in Ibadan, Nigeria, compare the results with the\nWorld Health Organization guidelines, draw conclusions and make recommendations. Water samples\nwere obtained and analysed for Pb, As, Cd, Zn, Cu, Cr, Fe and Mn. Overall, the minimum concentrations\nof Pb, As, Cd, Cr and Fe in the well water samples were below detection limit (BDL). The maximum\nvalues were 0.02, 0.45, 0.01, 0.445, 0.135, 0.09, 0.245 and 0.155 mg/l respectively. In the surface water\nsamples, the minimum concentrations of Pb, As, Cd and Cr were below detection level, while the\nmaximum concentrations of Pb, As, Cd, Zn, Cu, Cr, Fe and Mn were respectively 0.075, 0.05, 0.001,\n0.445, 0.120, 0.065, 0.45 and 0.16 mg/l. No evidence of contamination of these water supply sources with\nheavy metals was found going by the fact that the values obtained were lower than the guideline values\nestablished by the World Health Organization. A possible exception is As which in some samples had\nhigher concentrations than the WHO guideline. The recommendations of the study include continuous\nand close monitoring of these private drinking water supplies. There must also be strict compliance to\nregulatory limits in sludge and wastes to be released into the environment, and enforcement of other\nenvironmental protection regulations. Findings from this study will be of immense help to the general\npublic as well as researchers and environmental regulators working in this area of interest in\ndeveloping countries.\nKey words: Heavy metals,...
The role of water hyacinth on removal of organic carbon was investigated in free water constructed\nwetlands. A model incorporating the activities of suspended and biofilm biomasses was developed in\norder to simulate the various processes involved in the transformation and removal organic matter in\nthe water hyacinths constructed wetland. The results show that the major processes governing the\norganic carbon transformation and removal in a water hyacinth constructed wetlands system are\nsedimentation of solids (56.5%), regeneration of organic carbon (25.5%), oxidation of organic carbon to\ncarbon dioxide (6.4%), plant decay (4.4%) and uptake of organic carbon by heterotrophic bacteria\n(4.2%). The total permanent removal of organic material was 26.7% of the total influent chemical oxygen\ndemand (COD). The COD removal efficiency of the model when the effect of biofilm was considered was\n40.5%. However, in absence of biofilm activities, only 34.0% of COD was removed. This confirms the\nsignificance of the water hyacinth roots as an attachment media, which is extremely biologically active\nin assisting the organic carbon removal in the water hyacinth constructed wetland....
Health centers represent an incontestable release source of many toxic compounds in the environment due to laboratory activity or medicine excretion. The major sources of medical waste are released from healthcare institutions such as hospitals, clinics, veterinary hospitals and diagnostic laboratories. This paper points out the physico - chemical characterization of health centers wastewater discharged with or without prior treatment into the environment from major hospitals and diagnostic laboratories located in Jaipur (Rajasthan state), India. Physico - chemical parameters such as DO, temperature, BOD5, COD, pH, free CO2, TS, TDS, TSS, chlorine residue are measured as per standards methods. The study reported that untreated wastewater from SMS hospital, shows values of BOD5, COD, TDS, chlorine residue are 468±6.8, 896±8.5, 349±0.8, 703±4.0 3.04±0.1 respectively which were far greater than the standard values. The present study revealed that the hospital wastewaters though show some toxic parameters whose values are higher than the WHO standards. Physico - chemical analysis seems to be a viable option for the disposal of health centers effluents. Further, Diagnostic laboratories also represent small but significant amount of toxic waste into the environment....
Most water table aquifers are polluted, yet they are the primary sources of urban and rural water supply.\nSustainable hydrology in this millennium will capture in-situ treatment and protection of shallow\naquifers particularly in developing countries. Permeable reactive barrier (PRB), biological and\nelectrochemical methods with air and steam injection techniques will advance. Ex-situ pump and treat\nmethod is slow, costly and unsustainable. Many private treatment plants for pump-treat-use have been\nabandoned due to unsatisfactory output and operational problems. In-situ treatment of polluted aquifer\nstarts with mapping pollution source(s), identifying stressors and migration pathway, estimating\nquantum of stress, and terminating release of stressors from the source. Sustainable hydrology shall\nalso include developing hydrologic models code that can predict pollution, treatment method; amount\nand period of treatment. This shall be based on the characteristics of the aquifers; the pollution stress\nand the subsurface....
Using geographic information systems (GIS) and remote sensing integration to determine runoff\ncaused due to rainfall from watershed has performed increasingly attention in recent years. This study\nwas conducted in the Khartoum State. Curve Number (CN) method was applied for estimating the runoff\ndepth in the watershed. Hydrologic soil group and land use maps were generated in GIS Environment.\nHydrologic soil groups and land use maps were used to generate the CN map. Soil Conservation\nServices-Curve number (SCS-CN) method was followed to estimate runoff for the watershed. It was\nfound that the model can predict runoff reasonably well. It could be concluded that the SCS-CN method\ncan be applied to predict runoff volumes for planning of various conservation measures and for other\nwater resources applications....
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