I thought the recommendation to build a separate wastewater system for greywater was an excellent idea and consistent with practices elsewhere in the world where septic systems are difficult to maintain.
posting at the University of Tennessee (Samuel) describes student work on bio-retention beds where *...the five beds have now been planted full of native water loving goodness! The greywater bed is piped in, but can't be turned on until city ordinances allowing it have passed in June*.
It sounds like Tennesssee might be rethinking their stance on greywater reuse, at least considering a more local approach to decision making on the issue! Greywater governance in action.