3E Memtech has successfully demonstrated the feasibility of recycling cooling tower blowdown water on-site at Changi Airport Terminal 4 and Nanyang Technological University (NTU). This initiative, powered by the 3E-NF60 nanofiltration (NF) membrane, showcases significant water savings, operational cost reduction, and environmental benefits.
Pilot Stage Performance: Water Quality Improvement
During the pilot phase, water quality parameters were closely monitored, and the 3E-NF60 membrane exhibited exceptional purification capabilities:
- Turbidity removal: Over 98%, ensuring crystal-clear water quality.
- Hardness reduction: Between 40-50%, minimizing scaling and corrosion risks in cooling systems.
- CODcr retention: Exceeding 50%, significantly reducing organic pollutants.
Cost-Effective Operations
The system was evaluated for five days (January 20-24, 2025) under the following conditions:
- Operating pressure: 3 bar
- Daily runtime: ~8 hours
- Permeate production: 12.0 m³/day (excluding backwash, only air scouring)
- Total power consumption: 13.92 kWh
The electricity cost per cubic meter of recycled water was calculated as 0.253 SGD, while the estimated chemical cost was 0.04 SGD/m³, bringing the total cost to 0.257 SGD/m³.
Significant Cost Savings and Sustainability
Compared to Singapore’s current municipal water price of 2.94 SGD/m³, the 3E-NF60 NF process operates at just 10% of the cost. This makes it a highly economical and sustainable alternative, converting low-quality cooling tower blowdown into a stable and reusable water source.
The recycled water meets Singapore’s strict water quality standards (SS <5 mg/L, COD <30 mg/L), ensuring regulatory compliance while enabling industries to achieve substantial water savings and cost reductions.
