Research Article
Stone Quarries and Hydrological Regime of Roshi with Emphasis on Sedimentation
Suman Shrestha,
Prachand Man Pradhan,
Hari Krishna Shrestha
Issue:
Volume 9, Issue 4, December 2023
Pages:
86-96
Received:
26 September 2023
Accepted:
17 October 2023
Published:
28 October 2023
Abstract: Nepal is a country with many mountains, situated in Hindukush Himalayas. Stone quarrying is currently accompanying the rapid expansion of physical infrastructure in the Roshi River and its tributaries. This study aims to establish the discharge and suspended sediment rating curve of the Roshi River. It also includes the impact of the stone quarries in the Roshi River during operation and non-operation at the upper Roshi watershed, Nepal. The data includes stage data, measurement of discharge, and suspended sediment in the years 2022 and 2023. The regression analysis was conducted with the development of a discharge rating curve having a coefficient of determination R2 = 0.83. The suspended sediment rating curve of the annual and monsoon, of the year 2022 was developed with a coefficient of determination of 0.23 and 0.39 respectively. The average suspended sediment concentration at tributary Roshi is 203.04 percent higher than at upstream. The increase in average suspended sediment concentration at main Roshi concerning tributary Roshi is 14.25 percent. Further, the decrease in average suspended sediment concentration due to the non-operation of the stone quarry in January 2023 concerning December 2022 is 52.13 percent in tributary Roshi and 12.59 percent in the main Roshi River. Furthermore, the increase in SSC during the operation of stone quarry including monsoon contribution is 682.97 percent higher than during non-operation. The increase in SSC during the operation of stone quarry excluding monsoon contribution is 64.34 percent higher than during non-operation. The study will facilitate Panauti hydropower and the concerned authorities of Panauti to adopt various measures to control sediment discharge from stone quarries at Roshi for sustainable development of the Roshi watershed.
Abstract: Nepal is a country with many mountains, situated in Hindukush Himalayas. Stone quarrying is currently accompanying the rapid expansion of physical infrastructure in the Roshi River and its tributaries. This study aims to establish the discharge and suspended sediment rating curve of the Roshi River. It also includes the impact of the stone quarries...
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Research Article
Defluoridation of Groundwater by Activated Carbon Derived from Water Hyacinth (Pontederia crassipes) by Phosphoric Acid Activation
Eric Mugambi Muchunku*,
Peter Kuria Ndiba,
Erick Auma Omondi
Issue:
Volume 9, Issue 4, December 2023
Pages:
97-107
Received:
12 October 2023
Accepted:
7 November 2023
Published:
17 November 2023
Abstract: Elevated concentration of fluoride in groundwater poses serious health concerns in communities that depend on the groundwater for their drinking water. Efforts to develop appropriate defluoridation techniques have experienced challenges such as low efficiency, unaffordability, skill shortage, and cultural perceptions. This study evaluated the use of water hyacinth-derived activated carbon as an indigenous, environment-friendly, and socio-economically acceptable alternative technique for defluoridation. Dried water hyacinth stems were impregnated with concentrated phosphoric acid to three times their weight, and then calcinated in a muffle furnace by increasing the temperature at a rate of 5°C /min up to 600°C. The produced WHAC was characterized by scanning electron microscopy (SEM), proximate analysis and Fourier transform infrared (FT-IR) spectroscopy. Batch experiments determined effects of pH, contact time and adsorbent dosage on defluoridation efficiency. The results revealed a bulk density of 0.123 g/cm3, ash content 8.9% and fixed carbon content 66.7%. These characteristics were comparable to those of selected commercial activated carbons (CACs). The ash content was less than 10% and fixed carbon greater than 65%, suggesting high surface area and porosity that are indicative of a good quality activated carbon. The SEM revealed a rough and irregular texture illustrating high porosity. The WHAC achieved a fluoride removal efficiency of 82.6%, at pH 3 and contact time of 120 min. Fluoride adsorption by WHAC was best described by Freundlich isotherm model with a correlation factor (R2) of 0.952 and an adsorption intensity (n) of 0.285 that indicated heterogeneity of the WHAC. The adsorption was described by pseudo-second order kinetic model with a correlation factor (R2) of 0.999 and comparable experimental and theoretical adsorption capacities of 0.4608 and 0.4656, respectively, which suggested chemisorption adsorption of fluoride onto WHAC.
Abstract: Elevated concentration of fluoride in groundwater poses serious health concerns in communities that depend on the groundwater for their drinking water. Efforts to develop appropriate defluoridation techniques have experienced challenges such as low efficiency, unaffordability, skill shortage, and cultural perceptions. This study evaluated the use o...
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