This paper reports study on the removal of As (V) by chitosan nanospheres following batch studies conducted as a function of dosage, contact time and temperature. The kinetic investigation of the removal process reveals that the uptake of As (V) ions by chitosan is very rapid in the first 40 min and then an equilibrium adsorption is achieved in next 20 min. The adsorption data has been applied to Langmuir and Freundlich isotherm equations and various experimental parameters such as solid to liquid ratio, pH, temperature and contact time are varied to optimize the conditions for the removal of arsenic ions. Antibacterial studies are also performed on native chitosan and silver nanoparticles loaded chitosan nanospheres and dissolved oxygen is calculated in water samples treated with chitosan and Ag-chitosan nanospheres. Escherichia coli is used to test the bactericidal efficacy of synthesized Ag-chitosan nanospheres. These nanospheres are found to have significantly higher antibacterial activity than the native chitosan nanospheres.