I'd be interested to see how this works in practice and how much this costs, that vortex unit looks like one of those Aussie ones from
http://www.waterco.eu/products?ptitle=multicyclone-plus-filter_87. There very cheap !!
There made for swimming pool installations where the solid content in water is comparatively low compaired to us. Also, these units claim to only filter "upto 80%" of solids which to be fair may be enough for us with the addition of couple of pre and post filters to make up the difference. Morclean say they use 5 filters in all.
On my research on the subject I concluded that I would probably start with one of these units as proof of concept then move onto the vortex filters used in the mining industry which remove 98% of solid content down to 10 microns. In this instance I'd prefilter with stainless mesh then polish off with a vessel. The foot print would also be very small and compact and more importantly it would be bullet proof.
I've not actually put any of this into practice as I don't have the work to justify it, however I recon it's only a matter of time before local authorities force us to capture our water and at least filter before disposal, I can do this now. I also think it's a good selling point that we can work with a continous closed loop system as we'd be using the same water over and over again.