Hoang Thi Trang, Kasemsan Manomaiphiboon*, Nkrintra Singhrattna and Nosha Assareh
Abstract: This study assessed the prediction performance of seven satellite precipitation products using the 3-hourly gauge data in 2014-2016 across Thailand, as the representative country in Upper Southeast Asia. They are Tropical Rainfall Measuring Mission near-real-time (TRMM_RT), gauge-adjusted TRMM (TRMM), Climate Prediction Center Morphing (CMORPH), Global Precipitation Measurement (GPM), Global Satellite Mapping of Precipitation - Standard (GSMaP_S), gauge-adjusted GSMaP (GSMaP_G), and Precipitation Estimation from Remotely Sensed Information using Artificial Neural Network (PERSIANN). The evaluation methods include bias, error, and correlation, event detection, phase of diurnality, variance partitioning, and wavelet coherence. No single product is universally superior over all aspects. Nevertheless, it is possible to suggest CMORPH as the best performing based on the majority of the methods. GPM and GSMaP_S also perform reasonably, except for incompatibility in the diurnality phase. These three products capture precipitation fluctuations to some extent, as robustly indicated by variance partitioning and wavelet coherence. GSMaP_G has the true strength in bias, error, and correlation but fails to capture the fluctuations. GSMaP_G and GPM detect the “light” class of precipitation event the best but only GPM continues to predict relatively well for the “moderate” and “heavy” classes. TRMM_RT appears to have relatively large bias and error and does not reasonably capture the fluctuations. PERSIANN has relatively large error and does not perform well for correlation and event detection.
Keywords: Rainfall, Harmonic analysis, Monsoon, Spectral decomposition, Autocorrelation.
Orhorhoro Ejiroghene Kelly*, Arhore Oghenegare A and Okuma Silas Oseme
Abstract: Biogas produced from municipal solid waste requires proper purification due to the presence of siloxanes and other impurities. Siloxanes are converted to silicon dioxide at the combustion temperature and this forms deposits on the combustion surfaces of the engine components. Thus, to prolong the equipment life, purification is requires. This study therefore focused on the determination and removal of siloxane in energy recovery of biogas from municipal solid waste. Air Toxics Method was adopted for sampling and the composition of siloxane and other impurities were determined using gas chromatograph. Two purification filters were developed using transparent plastic container, iron sponge, iron fillings, silica gel, activated carbon made from palm kernel shell and calcium oxide. The biogas produced was divided into sample A, sample B, sample C, and sample D and evaluated before and after purification for the presence of siloxanes and other possible impurities. It was observed that the percentage composition of produced methane increases with continuous anaerobic digestion of substrates while the percentage composition of siloxanes, and other impurities decrease with duration and extent of biomethanation. The results obtained also confirm the present of siloxanes in the four samples analyzed (0.628 mg/m3 for sample A, 0.638 mg/m3 for sample B, 0.613 mg/m3 for sample C, and 0.625 mg/m3 for sample D). However, after purification, the concentration of siloxane was reduced tremendously (0.628 mg/m3 for sample A, 0.638 mg/m3 for sample B, 0.613 mg/m3 for sample C, and 0.625 mg/m3 for sample D).
Keywords: Siloxane, Biogas, Purification, Municipal Solid Waste, Impurities.
Hency H. Thacker* and Vijay R. Ram
Abstract: Adsorption is one of the upcoming techniques for waste water remediation due its non-destructive properties and its ability to target wide range of contaminants. Different types of adsorbents include agro-based adsorbents, raw or modified minerals, polymeric materials, nanomaterials and so on. Modification of agro-based adsorbents or lignocellulosic materials using acids, alkali, surfactants, copolymers, nanomaterials leads to increase in adsorption capacity and improve its textural properties. Activated carbon posses larger surface area, chemical inertness, mechanical stability and hence are one of the promising adsorbents for removal of heavy metals from waste water. Also conversion of lignocellulosic materials to activated carbon helps to convert it to valuable useful substances. The present review includes various lignocellulosic materials for fabrication of activated carbon, effect of activating agent and carbonization temperature on surface properties, and their applicability in adsorption of heavy metals from aqueous phase.
Keywords: Adsorption, Activated carbon, physical activation, chemical activation, heavy metals.
M. Srinivasarao, K. Ramasudha and C.V.K. Bhanu
Abstract: Grid-Connected Solar Water Pumps for irrigation are being favoured for developing countries, like India, primarily because of the available rural grid infrastructure. One of the major benefits of these systems is the provision of feeding excess energy into the grid. This increases the revenue of the farmer as well as avoid over-exploitation of groundwater resources. Over-exploitation of groundwater resources is a major threat both in stand-alone and grid-connected systems. This paper proposes a methodology to accurately estimate the excess energy available after meeting the energy required for feeding the water to a specific crop at a given location. With this the farmer will be able to estimate the additional revenue they will be getting through buy-back of excess energy and the utilities, the amount of excess energy available through these systems, for planning. This will help promote KUSUM, a scheme offered by the Government of India to solarize one million grid-connected pumps. The proposed methodology is implemented for a location in Andhra Pradesh based on the guidelines in the scheme and the results presented.
Keywords: Grid-connected Solar Water Pumps; KUSUM; Utilizability; Buy-back scheme; over-exploitation of ground water.