water treatment plant vapor calculations

midricks

Hi all
I need your help in computing the following :
pls i need the formula if possible

A water treatment plant producing a 4500 m3 R.O regect water of TDS 7000-8000
Evaporation atrificial bond is required
minimum sise of each evaporation area 40000m2 depth 0.5 mtr
HOW MANY I NEED ?
ِAve. yearly Temp 40 degree
Humidity :50%
Wind speed 15 km/hr ( ave.)
location 400 mtr above sea level

Thanks in advance