[1] N. R. Warner, J. Levy, K. Harpp and F. Farruggia, “Drinking Water Quality in Nepal’s Kathmandu Valley: A Survey and Assessment of Selected Controlling Site Characteristics,” Hydrogeology Journal, Vol. 16, No. 2, 2008, pp. 321-334. doi:10.1007/s10040-007-0238-1
[2] M. C. Kundu and B. Mandal, “Assessment of Potential Hazards of Fluoride Contamination in Drinking Groundwater of an Intensively Cultivated District in West Bengal, India,” Environmental Monitoring Assessment, Vol. 152, No. 1-4, 2009, pp. 97-103. doi:10.1007/s10661-008-0299-1
[3] H. H. Comly, “Cyanosis in Infants Caused by Nitrates in Well Water,” The Journal of the American Medical Association, Vol. 257, No. 22, 1987, pp. 2788-2792.
[4] D. Forman, S. Al-Dabbagh and R. Doll, “Nitrates, Nitrites and Gastric Cancer in Great Britain,” Nature, Vol. 313, No. 6004, 1985, pp. 620-625. doi:10.1038/313620a0
[5] D. T. Ha, R. Kusumoto, T. Koyama, T. Fuji and K. Furukawa, “Evaluation of the Swim-Bed Attached-Growth Process for Nitrification of Hanoi Groundwater Containing High Levels of Iron,” Japanese Journal of Water Treatment Biology, Vol. 41, No. 4, 2005, pp. 181-192. doi:10.2521/jswtb.41.181
[6] T. Stembal, M. Markic, N. Ribicic, F. Briski and L. Sipos, “Removal of Ammonia, Iron and Manganese from Grou- ndwaters of Northern Croatia-Pilot Plant Studies,” Process Biochemistry, Vol. 40, No. 1, 2005, pp. 327-335. doi:10.1016/j.procbio.2004.01.006
[7] J. Park, S. Lee, J. Lee and C. Lee, “Lab Scale Experiments for Permeable Reactive Barriers Against Contaminated Groundwater with Ammonium and Heavy Metals Using Clinoptilolite (01-29B),” Journal of Hazardous Materials, Vol. 95, No. 1-2, 2002, pp. 65-79. doi:10.1016/S0304-3894(02)00007-9
[8] WHO, “Guidelines for Drinking Water Quality,” 2nd Ed- ition, World Health Organisation, Geneva, 1996.
[9] N. R. Khatiwada, S. Takizawa, T. V. N. Tran and M. Inoue, “Groundwater Contamination Assessment for Sustainable Water Supply in Kathmandu Valley, Nepal,” Water Science and Technology, Vol. 46, No. 9, 2002, pp. 147-154.
[10] K. Pochana, J. Keller and P. Lant, “Model Development for Simultaneous Nitrification and Denitrification,” Water Science and Technology, Vol. 39, No. 1, 1999, pp. 235-243. doi:10.1016/S0273-1223(98)00789-6
[11] K. Chen, S. Lee, S. Chin and J. Houng, “Simultaneous Carbon-Nitrogen Removal in Wastewater Using Phosphorylated PVA-Immobilized Microorganisms,” Enzyme and Microbial Technology, Vol. 23, No. 5, 1998, pp. 311- 320. doi:10.1016/S0141-0229(98)00054-4
[12] N. Hashimoto and T. Sumino, “Wastewater Treatment Using Activated Sludge Entrapped in Polyethylene Glycol Prepolymer,” Journal of Fermentation and Bioengineering, Vol. 86, No. 4, 1998, pp. 424-426. doi:10.1016/S0922-338X(99)89019-9
[13] W. M. Rostron, D. C. Stuckey and A. A. Young, “Nitrification of High Strength Ammonia Wastewater: Comparative Study of Immobilisation Media,” Water Research, Vol. 35, No. 5, 2001, pp. 1169-1178. doi:10.1016/S0043-1354(00)00365-1
[14] C. Vogelsang, A. Susby and K. Ostgaard, “Functional Stability of Temperature-Compensated Nitrification in Domestic Wastewater Treatment Obtained with PVA-SBQ/ Alginate Gel Entrapment,” Water Research, Vol. 31, No. 1, 1997, pp. 1659-1664. doi:10.1016/S0043-1354(97)00009-2
[15] V. Libman, B. Eliosov and Y. Argaman, “Feasibility St- udy of Complete Nitrogen Removal from Domestic Wa- stewater by Consequent Nitrification-Denitrification Using Immobilized Nitrifiers in Gel Beads,” Water Environment Research, Vol. 72, No. 1, 2000, pp. 40-49. doi:10.2175/106143000X137095
[16] G. Cao, Q. Zhao, X. Sun and T. Zhang, “Integrated Nitrogen Removal in a Shell and Tube Co-Immobilized Cell Bioreactor,” Process Biochemistry, Vol. 39, No. 10, 2004, pp. 1269-1273. doi:10.1016/S0032-9592(03)00256-5
[17] Z. Zhang, J. Zhu, J. King and W. Li, “A Two-Step Fed SBR for Treating Swine Manure,” Process Biochemistry, Vol. 41, No. 4, 2006, pp. 892-900. doi:10.1016/j.procbio.2005.11.005
[18] R. Blackburne, Z. Yuan and J. Keller, “Demonstration of Nitrogen Removal via Nitrite in a Sequencing Batch Reactor Treating Domestic Wastewater,” Water Research, Vol. 42, No. 8-9, 2008, pp. 2166-2176. doi:10.1016/j.watres.2007.11.029
[19] W. Khanitchaidecha, T. Nakamura, T. Sumino and F. Kazama, “Performance of Intermittent Aeration Reactor on NH4-N Removal from Groundwater Resources,” Water Science and Technology, Vol. 61, No. 12, 2010, pp. 3061-3069. doi:10.2166/wst.2010.247
[20] T. Sumino, K. Isaka, H. Ikuta and B. Osman, “Simultaneous Nitrification and Denitrification Using Activated Sludge Entrapped in Polyethylene Glycol Prepolymer,” Japanese Journal Water Treatment Biology, Vol. 43, No. 3, 2007, pp. 121-128.
[21] American Public Health Association, “Standard Methods for the Examination of Water and Wastewater,” 19th Edition, Springfield, New York, 1995.
[22] M. H. Schroth, J. D. Istok, G. T. Conner, M. R. Hyman, R. Haggerty and K. T. O. Reilly, “Spatial Variability in Situ Aerobic Respiration and Denitrification Rates in a Petroleum-Contaminated Aquifer,” Ground Water, Vol. 36, No. 6, 1998, pp. 924-937. doi:10.1111/j.1745-6584.1998.tb02099.x
[23] Metcalf and Eddy, “Wastewater Engineering, Treatment and Reuse,” 4th Edition, McGraw-Hill, Singapore, 2004.
[24] R. H. Wijffels, C. D. de Gooijer, S. Kortekaas and J. Tramper, “Growth and Substrate Consumption of Nitrobacter Agili Cells Immobilized in Carrageenan: Part 2. Model Evaluation,” Biotechnoloty and Bioengineering, Vol. 38, No. 3, 1991, pp. 232-240. doi:10.1002/bit.260380304
[25] W. A. J. van Benthum, M. D. M. van Loosdrecht and J. J. Heijnen, “Control of Heterotrophic Layer Formation on Nitrifying Biofilms in a Biofilm Airlift Suspension Reactor,” Biotechnology and Bioengineering, Vol. 53, No. 4, 1997, pp. 397-405. doi:10.1002/(SICI)1097-0290(19970220)53:4<397::AID-BIT7>3.0.CO;2-I
[26] D. D. Forcht and W. Verstraete, “Biochemical Ecology of Nitrification and Denitrification [Soils],” Advances in Microbial Ecology (USA), Vol. 1, No. 1, 1997, pp. 135-214.
[27] R. Nogueira, L. F. Melo, U. Purkhold, S. Wuertz and M. Wagner, “Nitrifying and Heterotrophic Population Dynamics in Biofilm Reactors: Effects of Hydraulic Retention Time and the Presence of Organic Carbon,” Water Research, Vol. 36, No. 2, 2002, pp. 469-481. doi:10.1016/S0043-1354(01)00229-9
[28] E. J. T. M. Leenen, A. M. G. A. van Boxtel, G. England, J. Tramper and R. H. Wijffels, “Reduced Temperature Sensitivity of Immobilized Nitrobacter Agili Cells Ca- used by Diffusion Limitation,” Enzyme and Microbial T- echnology, Vol. 20, No. 8, 1997, pp. 573-580. doi:10.1016/S0141-0229(96)00214-1