Kevil, look on that ...
Published by Ilia Svirsky, Water Technologies Centre Siberia Ltd. - Regional Director
Kevil, look on that http://www.azud.com/en/treatment/products/azud_watertech_gw.aspx
http://www.azud.com/imagenes/tratamiento2/2014527111247AZUD%20WATERTECH%20GW_EN.pdf
I think this technology could be appropriated for your greywater daily volumes.