SUITABILITY OF ATTANAGALU OYA AS A DRINKING WATER SOURCE

Attanagalu oya basin is situated between the two major river basins Kelani and Maha Oya .It plays amajor role in national water supply since it contains major national water supply and drainage boardintakes. This study intends to study the quality of water of the Attanagalu Oya and its suitability fordrinking purpose. Because of its significance as a drinking water source it is important to maintain thequality of the water. Samples were collected from ten selected sampling locations along the main riverincluding one near the origin of the river, near the sea outfall, NWS&DB intakes from the main river.Other locations were selected so as to have the similar distance between sampling locations Samplingwas taken during both high and low flow rate conditions. Analysis was done on physical, chemicaland biological parameters.Results showed that records of COD, BOD, DO, pH, nutrient are low during the high flow rate whilethe levels of turbidity, metal iron total coliform and faecal coliform are high during the high flow rate

Investigation of the pollution extent of Attanagalu Oya

Attanagalu Oya basin is located in Gampaha district. The river flows across Gampaha, Katunayake and Negambo. The Longest length of the river course is about 76 km. Previous work conducted on this river revealed considerable socio-economic activities at riverbanks resulting in indiscriminate disposal of waste. This study is intended to evaluate pollution extend of Attanagalu Oya  along the main stem of the river. Water samples were collected from ten selected sampling locations along the main river stem including the origin of the river, near the river outfall and from the NWS&DB intakes of the river. Samples were tested for major  physical, chemical and microbiological parameters monthly for two consecutive years. Turbidity, Conductivity, pH,NO3-, PO43-, BOD, COD, DO, selected metals, total and faecal coliform were analysed. DO, BOD, COD, NO3-, PO43-  and heavy metals variation of the river is significantly different among sampling locations. WQI of the river decreases towards the downstream both in dry and rainy seasons of the riverWater quality of upstream is mainly influenced by domestic sewage and drainages from cultivated lands. In the latter stretch, except the aforementioned pollution sources, industrial effluents and salt water intrusion are the main factors influencing water pollution.Water quality at some sites signified that the water is not suitable for human consumption  without treatment. The study showed that the river is fairly polluted, and the pollution increases towards the later stretch, the effects being significant in the urban areas. The results obtained from this study would further facilitate water quality protection and water resources management of the river.Key words: water quality, WQI, river, pollution, industrial discharge

Development of dye-sensitized solid-state ZnO/D149/CuSCN solar cell

Dye-sensitized solid-state solar cells (DSSC) based on n-type ZnO and p-type CuSCN have been fabricated with highest recorded power conversion efficiency. The working electrode of the cell is composed of D149 dye-coated ZnO-based interconnected nanoparticulate (20 nm) mesoporous layer with ZnO-based dense layer which was prepared on fluorine-doped tin oxide (FTO) glass substrates. CuSCN deposition was carried out according to the previously reported procedure which ensures enhanced p-type conductivity of CuSCN. The surface morphologies of the ZnO dense layer, ZnO porous layer and CuSCN layer have been visualized using scanning electron microscopy (SEM). The cells were fabricated with the configuration of FTO/ZnO dense layer/ZnO porous layer/D149/CuSCN/Graphite/Cr-coated FTO. Then the cells were characterized using I-V data as functions of the dense layer resistance (which is proportional to the thickness of the dense layer) and the porous layer thicknesses. The optimum dense layer is found to have 1500 Omega/rectangle sheet resistance. The cell with porous layer thickness of 9 mu m at this dense layer resistance shows the maximum power conversion efficiency of 2.28%. The solar cell parameters of this optimized cell are an open circuit voltage of 0.55V, a fill factor of 0.51 and a short-circuit current density of 8.2mAcm(-2)

Preparation of fluoride-doped tin oxide films on soda-lime glass substrates by atomized spray pyrolysis technique and their subsequent use in dye-sensitized solar cells

The development of a novel method for the fabrication of low-cost, transparent, conducting glass (F--doped SnO2 layer on soda lime glass, FTO) by a specially developed atomized spray pyrolysis technique using cheap soda lime glass in place of commercially used expensive glass at a comparatively lower temperature of 450 degrees C is presented. The use of these FTO plates in dye-sensitized solar cells (DSCs) will also be described. The optimum temperature of 450 degrees C for the FTO layer on soda lime glass is obtained by carrying out atomized spray pyrolysis of the precursor solution onto the soda lime glass substrate at several different temperatures and by characterizing the materials obtained at each temperature by X-ray diffraction analysis. The FTO layers formed at 450 degrees C have also been characterized by scanning electron microscopy (SEM) for morphology, grain size, and film thickness and by UV-visible transmittance spectroscopy for the optical transmission in the visible range. The electrical properties of the FTO film prepared at 450 degrees C are estimated by the van der Pour method and Hall measurements. The FTO films have a uniform texture with smaller grains (>= 50 nm) embedded in cages formed by larger particles

Efficient solid-state dye-sensitized n-ZnO/D-358 dye/p-CuI solar cell

This paper describes the preparation and characterization of FTO/TiO2 dense layer/ZnO nanoporous layer/D-358 Dye/CuI hole collector/Cr-coated FTO and FTO/ZnO dense layer/ZnO nanoporous layer/D-358 Dye/CuI hole collector/Cr-coated FTO dye-sensitized solid-state solar cells. The variations of the solar cell parameters on the thickness of the TiO2 or ZnO dense layer are described. As the thickness (and hence the sheet resistance) of the TiO2 dense layer is increased, the conversion efficiency is gradually increased up to 2.6% at a sheet resistance of 370.0 Omega/square and beyond which it decreases. At this optimum thickness of the TiO2 dense layer, the best conversion efficiency is obtained when the thickness of the ZnO nanoporous layer is 15 mu m. Use of ZnO dense layer instead of TiO2 dense layer also shows the similar trend of variation of solar cell parameters as the thickness of the dense layer is increased. The best conversion efficiency of 3.2% is obtained when the sheet resistance of the ZnO dense layer is 2500 Omega/square and the thickness of the ZnO porous layer is 15 mu m. (C) 2013 Elsevier Ltd. All rights reserved

Vein graphite-based counter electrodes for dye-sensitized solar cells

This paper describes the use of ball-milled vein graphite and ball-milled floated graphite counter electrode (CE) materials in dye-sensitized solar cells. The vein graphite used was ball milled, sieved and fraction of particle sizes in the 45-63 pm was used (BMG). Another fraction in the same size range was floated in water to get ball-milled floated graphite (BMFG). Both samples were extensively characterized by electrochemical techniques, Raman spectroscopy and by Total Carbon Analysis. The performance of dye-sensitized solar cells (DSCs) prepared using these CEs were optimized for their adhesion, sintering temperature and thickness. Best performances were obtained for the DSC with CE prepared using graphite:morphol mass ratio of 5:3, sintering temperature of 350 degrees C and the thickness of 250 mu m. Most of the impurities in ball-milled graphite can be removed by the floating technique and the DSC fabricated with ball-milled floated graphite based CE gives 24% better performance than that constructed using just ball-milled graphite based CE. The best conversion efficiency observed is 6.47%. Though this is less than that obtained using Pt CE, it is still very useful in practical applications as per cost considerations. (C) 2017 Elsevier B.V. All rights reserved