Greywater Reuse for Cooling (Luxury Hotel, Dubai)
A luxury hotel was trialing greywater (shower/laundry water) in its cooling tower makeup to cut potable use, but struggled to keep sufficient chlorine residual: the raw greywater had high TSS/TDS and organic load. We found that odor and contaminants in the greywater consumed chlorine quickly and fouled the tower. Drawing on Dubai’s focus on alternative water sources, we installed a pre-treatment train: coarse prefilters to strip solids, followed by activated carbon filters to remove odors and organics. Finally we added a Membrane Bioreactor (MBR) step to polish the greywater. These measures ensured the cooling tower saw high-quality makeup: lower TSS/TDS and no foul smells.
- Actions: Added multi-stage greywater treatment: sediment filters, activated carbon, and an MBR unit. Adjusted chemical feed to match the improved water quality.
- Results: Cooling tower chlorine is now easily maintained and microbiology is under control. Odors are gone, and no tower fouling has occurred. Reusing ~30–40% of makeup as treated greywater has cut potable water draw by tens of thousands of liters per month. At Dubai’s industrial rate (≈AED 8.8–10.1/m³ plus AED 1.1 surcharge), this reuse saves the hotel on the order of AED 50–100k/year. It also meets Dubai Green Building goals for water reuse.
