Design of a Constructed Wetland for Grey Water

Hi all, I am designing a wetland for treatment of grey water from showers at a charcoal factory in central Namibia where 200 people shower per day. The design loading is 10 m3 per day and using the Kickuth equation I have a surface area of about 65 m2. I have selected a horizontal flow SSFCW wetland with an existing septic tank as preliminary treatment. Has anyone in Southern Africa done a similar design with a cost projection for the materials required?  Thanks in advance  Megan