Engineering Design Cycle and Water Filter Creation

A humanitarian organization is helping a small rural village in a third-world country filter their polluted greywater supply. Your team of environmental engineers has been tasked to research ways to help cleanse their water.  You will use the engineering design cycle to create a usable water filter, then present findings for using it in the village. 
Start with identifying and explaining the problem/ question. Then go through each of the steps from our lab.

List and describe steps of the engineering design cycle that would be used to create a usable water filter.