Need to know about the grey water recycling plants for high rise structures in Mumbai, Maharashtra - Cost, area footprint and types available


I am an Architect doing research on effects of high density on the water supply in Mumbai for my Master's Thesis. I wanted to know what kind of grey water recycling plant is suitable for recycling 300kL of greywater per day. This is regarding a hypothetical study on potential of greywater recycling. Also what types of recycling plants for greywater are available in the market today and what are the general costs and area footprints of the respective plants. The 300kL of grey water generation is a rounded off figure for 6696 people who could stay in the high rise building using a daily usage of 135 lpcd.