U.N. report : Polluted water kills about 2.2 million a year ; wars claim fewer victims per year . Report also says wastewater could become valued resource if treated . Comment:
U.N. report : Polluted water kills about 2.2 million a year ; wars claim fewer victims per year . Report also says wastewater could become valued resource if treated . Upfront costs to build treatment plants would be expensive , report says .