Has anything been explored other than irrigating the water directly to the orchards or gardens? I saw in another post that storing the water or filtering through a reed bed is not recommended. Would a second stage filter something like a biofilter used in an aquaponics system provide adequate filtration to clean the water enough to add it to the grey water going to a constructed wetlands?
If you have the water tested first so you're confident no pathogens are coming through the tank, you could probably take the water direct to a constructed wetlands as the water exiting the tank is generally cleaner than grey water. But I would want to put some failsafe mechanism in place between the two. IF your tank were to block (eg. organic material that's too fine gets into the mix and clogs the filters), then sorting the blockage without diverting the water going to the wetlands wouldn't be advisable. You'd want some sort of other soakaway until the system is stable and working again.
At the end of the day, keeping everything aerobic (soil-based) is the surest guarantee your waste is being treated safely and thoroughly. Taking it into an anaerobic system (wetlands) does make potential problems more likely.
Can you explain the function of the green filter please? Is its purpose to clean the discharge water from the tank prior to safely ridding the system of it or is it supposed to clean the discharge water from the tank and be harvested for use in the garden for example? If the latter is the case, how do you harvest the clean water from the green filter? Perhaps the green filter IS the garden?
Next question ... does anyone have experience with this system in a desert climate where it may occasionally freeze at night (thus rendering gardening impossible for approximately 3 months a year) and high summer temperatures with extremely dry conditions exist for 3-4 months a year? Moderate temperatures but very dry conditions prevail the other 5-6 months each year. What does one do with the water during the non gardening months (and how will the green filter function in the occasional freeze)? Are there concerns with too rapid evaporation from the green filter during the hot dry months? Anybody using this system in the desert?
Yes, the greenfilter IS the garden. The greenfilter adds another layer of cleaning to the water exiting the tank. It's not intended to collect the water in any way but to use it for irrigation of trees, shrubs and ornamentals. To be on the safe side, you wouldn't use it for vegetables, but fruit trees and shrubs are fine.
Freezing at night is not a problem so long as the discharge water and the pipes carrying it are below the frost line. You can prevent evaporative losses by using a thick mulch on your greenfilter bed. If you've planted perennials in the bed, then they will always be taking up the water, even in winter, and the remainder will soak into the soil.