Current Environmental Engineering - Volume 4, Issue 3, 2017

Background: Air pollution affects both the health of living being and the materialistic resources. Amid the development of anthropogenic methods and machines, atmosphere has turned as a sink for foul gases and disorderly energy. Air pollutant discharges have deteriorated the natural composition of air in atmosphere at spatial manner. Method: The resulting losses from air pollutants can be minimized either by control at source (through air pollution control devices) or by diverting the receptor from pollution prone area. The second option requires an exact estimation of air pollutant’s concentration, which can be done by use of air pollution forecast models. There are many simulation models for forecasting the air pollutant concentration at any place. However, the results of these models are questioned many times because of inappropriate forecasting. In this paper author proposes a comprehensive multi-criteria process based upon statistical formulae for the evaluation of the performance of Air Pollution Forecast Models. Results: The performance of Air Pollution Models can be judged by error analysis, comparison of forecasted and observational data, use of statistical performance measurements and criteria. All these techniques are discussed for their suitability and guiding the modeler to select the optimal criteria for best model performance. Conclusion: The selection and use of specific evaluation criteria and their ability to interpret the results varies with the study area, prevailing meteorological conditions, formulation of model structure and behaviour of observed data and simulation results. A suitably selected performance criteria help in designing the best deliverable air pollution forecast model.

Background: Adsorption method, using activated carbon as an adsorbent, is being widely employed for the treatment of Copper(II) in effluent streams as the technique is simple, economical and effective. Method: The activated carbon despite being extensively used to remove copper(II) from the water and wastewater remains expensive. Application of the low cost adsorbents, prepared from agricultural wastes, have been explored by several researchers for the removal of Copper(II). Conclusion: This review highlights the adsorption potential of various agricultural waste based adsorbents along with activation methods, experimental conditions to achieve the optimum results, factors affecting the adsorption, adsorption isotherms and models

Background: Extensive use of electronic devices has led to the generation of large volumes of electronic waste (e-waste) worldwide. Currently, only a small fraction of e-waste is being treated or recycled appropriately; most e-waste is dumped, incinerated or disposed of in landfills Awareness regarding the environmental impact of managing e-waste has become significant in recent years. Objectives: The aim of this study was to estimate the environmental impact of recycling waste printed circuit boards (PCBs) using thermal plasma. In-depth characterization of particulates released during waste processing was carried towards ensuring that no toxic/hazardous elements get released to the atmosphere. Methods: Waste PCBs were cut to sizes ~10-15 cm; and were heated to 1500°C for 30 minutes in the oxygen depleted atmosphere of a plasma furnace. The exhaust gas from the reactor was cooled down in a heat exchanger, and was then passed through bag-house filters before exiting through a stack chimney. Particulates present in the exhaust gas were captured by the bag-house filters and characterized. Results: The proximate analysis of captured particulates showed a high concentration of carbon along with oxides, metals and other impurities. Particulate sizes were found to range between 3 to 200 μm, and their distributions at 10%, 50% and 90% levels were determined to be 1.696 μm, 10.318 μm and 55.042 μm respectively. Elemental analysis showed clear evidence for the presence of heavy metals (Cu, Al, Fe, Sn, Pb, Zn, Ni), hazardous metals (Sb, As, Cd), and several other metals in trace quantities. A small amount of precious metals was also detected. X-ray diffraction and FTIR studies were found to be in good agreement with results from other techniques. Conclusion: This study has shown that some metallic and other impurities could be carried out along with the exhaust gas during the recycling of e-waste. Effective control of gaseous emissions from ewaste recycling facilities is therefore crucially important for minimizing the environmental impact of ewaste management and processing.

Background: In arid region the river runoff is mainly consequence of rainfall over the river catchment area. Surface water discharge and base flow from the tributaries or other water sources e.g. lake, pond, glacier melting etc. also influences the river runoff. However, the way of contribution of rainfall and water discharge from other sources are dissimilar to impart river runoff. Method: In this paper simulation study of rainfall and runoff data of Kulfo River of Southern Ethiopia is carried out. Descriptive statistical and graphical techniques are used to comprehend and identify the inherent characteristics of raw data of river runoff and associated rainfall. The twenty years rainfall and runoff time series of Kulfo River is used to develop Transfer Function Model which is then after used to forecast the river runoff. The overall performance of the model was evaluated using statistical model evaluation criteria and working out the error statistics between the observed river runoff and model forecasts. Results: The results of runoff forecasting of Kulfo River for the next two year indicates that transfer function model performs excellently. The model results are outstanding to meet the mean river discharge and concurrently well capture the high and low values of runoff. Conclusion: Stochastic Transfer Function Model based upon the analysis of Time Series of Rainfall and River Runoff is an efficient tool for forecast of River runoff, quantification of River discharge, flood warning etc.

Background: Chemical fertilizers used for field crops have three main macronutrients components: nitrogen, phosphorus and potassium. They are the limiting factor to plant growth. Effluents from treated wastewater have appropriate concentration levels of those macronutrients to support crop production. Aim: The main purposes of this pilot case field study were: (i) to recover the valuable nutrients from sewage using a recirculating vertical flow constructed wetland planted on top with soybean (Glycine max, L.); (ii) to determine the potential of growing renewable feedstock commodities irrigated with treated effluent as a phytoremediation mechanism to clean wastewater onsite. Method: Grab samples of effluents from both septic tank and the constructed wetland were analyzed for water quality variables. Result: Mean treatment efficiencies (removal) were high for biochemical oxygen demand (98%), ammoniumnitrogen (97%), total suspended solids (96%), total Kjeldahl nitrogen (95%), fecal coliforms (93%), total nitrogen (85%), and total phosphorus (77%), while it was relatively low for potassium (43%). Supplementary irrigation or commercial fertilizers were not added during the growing season. The mean yield ± standard deviation (seed mean weight ± standard deviation) for fresh dried weight of soybeans crop was equivalent to 2,625 ± 1,653 kg/ha (0.21 ± 0.05 g/bean). Conclusion: These results show that soybean growing on top of a recirculating vertical flow constructed wetland could be a sustainable alternative technology and a green mechanism to remove pollutants (nutrients) from sewage. Also, nutrients recovery through direct reuse of treated sewage effluents as source of fertilizers and water to grow first-generation biofuels commodities such as soybean is feasible.

Objective: The article investigates the performance of homopolymer of castor oil and its four copolymers with methyl methacrylate (MMA), dodecyl acrylate (DDA), 1- decene (1-D) and styrene (ST) as biodegradable multifunctional additive in the formulation of eco-friendly lubricant. Method: Homopolymer of castor oil (CO) and its copolymers with 10% (w/w) of each of the comonomers were synthesized using azobisisobutyronitrile (AIBN) as initiator. The polymers were characterized by spectral techniques (FT-IR and NMR spectroscopy). The molecular weight of all the prepared polymers was determined by Gel Permeation Chromatography (GPC). Result: The thermal stability of the polymers was determined by thermo gravimetric analysis (TGA). Performance evaluation of all the prepared polymers in two different of mineral base oils as viscosity index improver (VII), pour point depressant (PPD) and antiwear was carried out according to standard ASTM methods. Biodegradability of all the samples was tested through soil burial test (SBT) method.

Objective: The simultaneous removal of NO and SO2 can be realized by adding soluble cobalt(II) salt into the aqueous ammonia solution. Method: Activated carbon is used as a catalyst to reduce hexamminecobalt(III) to hexamminecobalt(II) to sustain the NO removal efficiency. Solid NaOH has been explored to modify activated carbon to enhance its catalytic capability. The experiments have been performed to investigate the effects of carbon/NaOH(weight) ratio, activation temperature and activation duration on the catalytic ability of activated carbon. Result: After modification, the surface area and the acidity on its surface increase greatly, which are of benefit to enhancing its catalytic capability.

Background: Thermal power station uses natural coal for production of power at Tata steel limited, Jamshedpur, Jharkhand and produces residue of coal as a waste material called cinder. Industry also produces iron slag waste as a by-product during manufacturing of iron from its ores. Both waste materials were dumped at nearby open area of the plant called Jugasalai dump. Ratio of composition of both wastes as dumped material is about 80:20 (cinder:slag) and it is combindly called as “cinder”. Presently, this material has no uses and occupying costly land near the plant. Method: This material was investigated for its possible application in the construction of different bituminous pavement layers. Material was characterized for its physical, chemical and geotechnical properties pertaining to bituminous layers construction. Physical and chemical characterization contains different tests viz. shape of particle, natural moisture content, water absorption, loss on ignition, specific gravity, free swelling index, aggregate impact value and emission dispersive spectrometer tests whereas geotechnical characterization test has grain size analysis, Atterberg limit, Proctor compaction and California bearing ratio test. Different bituminous design mixes (Bituminous Macadam, Dense Bituminous Macadam and Semi Dense Bituminous Macadam) were carried out using cinder as partial replacement of fine aggregate (25 - 28 %). Marshall Stability test was carried out of bituminous mixes. Suitability of cinder waste was presented in the paper as per MORTH specification. Result: It was observed that cinder is crushable material. This leads to improper coating of bitumen on cinder particles. Conclusion: Therefore, it was concluded that material has no potential for the construction of bituminous layers.