This research was conducted to analyze drinking water quality of Kathmandu valley. Total 969 water samples (392 from dug wells, 287 from deep boring, 218 from treated water, 46 from tap and 26 from other water sources) received from different places of Kathmandu, Lalitpur and Bhaktapur districts during March 2012 to March 2013. These samples were analyzed for the determination of physical (pH, temperature, conductivity, turbidity), chemical (hardness, chloride, iron, arsenic, ammonia, nitrate) and microbiological (total Coliform) parameters. It was found that the temperature and nitrate were within the WHO standards while pH, conductivity, turbidity, chloride, iron, arsenic, ammonia, and Coliform bacteria exceeded the WHO standard guideline. In ground water ( well and Boring), pH, conductivity, hardness, turbidity, iron, arsenic, chloride, ammonia and total Coliform count crossed WHO standards as 5%, 2%, 0.8%, 36%, 51%, 0.1%, 2%, 11% and 86 % respectively. Hardness was within the standard in both  reated and tap water samples. Compared to treated water, pH, arsenic and chloride were within the standard in tap water. The common problematic parameters of different sources of drinking were turbidity, iron, ammonia and conductivity. Coliform bacteria were found in 36% samples of treated water whereas 80% tap water samples were contaminated from Coliform bacteria.DOI: http://dx.doi.org/10.3126/njst.v15i1.12027Nepal Journal of Science and TechnologyVol. 15, No.1 (2014) 115-120

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Cadmium (Cd), one of the hazardous elements in groundwater, is a severe threat to human health and ecological systems even at low concentrations. This study explores the effectiveness of commercial and self-synthesized nano-scale magnesia (NMgO) for remediating low-concentration Cd in groundwater as well as their associated removal mechanisms. The sorption kinetic data for both NMgOs were well fitted to the pseudo-second-order model and the calculated q values matched the experimental q values for both commercial and self-synthesized NMgOs. The sorption equilibrium data for both NMgOs were well fitted to the Langmuir isotherm model, with the maximum Cd sorption capacity (q ) of 19.25 and 16.54 mg/g at an initial concentration range of 5-200 μg/L and a temperature of 25 °C, for commercial and self-synthesized NMgOs, respectively. The combined sorption kinetics and equilibrium data suggest that the sorption onto both NMgOs follows a monolayer chemisorption. The scanning electron microscope-energy dispersive X-ray (SEM-EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffractometer (XRD) analyses show that the chemisorption of Cd onto commercial NMgO is due to the formation of Cd(OH), which precipitates on the sorbent surface. For the self-synthesized NMgO, it was demonstrated that the hydroxyl group plays a role in the chemisorption process and the amount of Cd sorbed on the sorbent was quantified. The results of batch experiments showed that both NMgOs removed Cd effectively, obtaining a removal efficiency of more than 99%, under different experimental conditions of pH, sorbent dosage, co-existing ions, and simulated groundwater. Results from both the sorption isotherm and desorption experiments indicated strong bonding between Cd and both NMgOs, suggesting that NMgOs are safe, effective, and practical sorbents to remediate Cd in groundwater.