I'm sure it's not like their system couldn't be enhanced to create potable water, but that would be something they would\could do down the road IMO.
They can't do everything at once and are now focused on selling their portable Rover.
Astronaut's use a silimar process to make water from urine and sweat, but NHYT's system does not use harmful chemicals or cumbersome older technologies such as filtration, distillation, chemicals or Bioremediation that NASA's system does
The waste water is treated via a highly effective electro-oxidation method, which is proprietary to Neohydro Technologies Corp. Neohydro's exclusive Brincell(TM) technology which employs high current electrolysis over proprietary electrodes, produces a highly potent oxidizing solution that eliminates or reduces BOD's, COD's, all bacteria's as well as separating sludge and oil, thus rendering the waste water "safe" and "clean"