Removing arsenic using PVA bottles.
Arsenic removal using water hyacinths.
Improving Water quality in India.
Safe Water Technology for Arsenic Removal.
Groundwater Arsenic Contamination in India: Vulnerability and Scope for Remedy
Arsenic conversion from As3 to As5 (What can I do if my water has high arsenic levels? second paragraph) 
Arsenic Removal - Manual