Although my answer maybe ...

Although my answer maybe slightly different than what you may be looking for I believe it is relevant.  In the Province of Saskatchewan, Canada the regulations to discharge into surface water bodies has been tightened up significantly...to the point where tertiary treatment is a requirement.  Tertiary treatment as you know is extremely expensive and where I live, is unaffordable to the 480+ towns.  Therefore for the past 8 years I have been the lead researcher for an Effluent Irrigation Woodlot solution just outside of Moose Jaw, Saskatchewan.  I have written over 1,700 pages of documentation on the project and have officially received the "go-ahead" from Saskatchewan Environment to proceed with the project to qualified communities.  Basically, in brief, with the woodlot, towns no longer have to discharge a single drop of water to surface water bodies.  The woodlot is not limited to just effluent but I tested effluent water as that is the main concern Saskatchewan is facing.  I have selected several hybrid poplar and willow trees that are hardy, disease resistant, and can take water from as little as what falls from the sky to 2.5 vertical meters per year of effluent and not a single tree was adversely affected.  The beauty is that after the enzymes are fixed, the woodlot can be converted to a camping site...I have visited 2 cities in the US and in Western Canada (British Columbia).  If interested in hearing more just email me at kurt.rasmussen@SaskWater.com

Sincerely,

Kurt Rasmussen, P.Eng.