The articles given by the previous researchers will definitely serve your process. Those are just a few of many, there are numerous numbers of articles dealing with arsenic remediation from the water.
Please check a couple of my papers. Besides, you can also check in the web the material that my advisor and myself created in Lehigh University´s lab. Brand name LAYNEART. Hope this will help you.
Nevertheless, first you have to characterize in a very detailed maner your water matrix.
You can remove arsenic from water by using Azolla sp. also. In Bangladesh there are some works done successfully in this area. I will send you the link very soon.