From Waste to Worth: Sustainable Reuse of Reverse Osmosis (RO) Reject Water in Kidney Unit

Year Submitted: 2025
Published Date:

Tags: Care Continuum, Chronic Care, Specialist Care, Care Process ＆ Redesign, Operational Management, Resource Allocation, Productivity, Cost Saving, Environmental Sustainability, Recycling, Water Waste

About this Content

Aims

This project aims to develop and implement a sustainable system to collect, store and repurpose RO reject water from the kidney dialysis unit for non-portable use such as irrigation. The objective is to reduce water wastage, lower operational costs, and support the hospital's commitment to environmental sustainability.

Background

Haemodialysis procedures in Kidney Unit require large volumes of ultrapure water, typically produced by Reverse Osmosis (RO) system. For every RO-treated water generated for dialysis, approximately 50-70% is rejected as wastewater due to the nature of purification process. This resulted in daily loss of thousands of litres of clean but non-portable water to main sewage line, leading to significant water wastage, higher utility costs, and a missed opportunity to enhance the hospital's environmental sustainability. Given the increasing emphasis on resource conservation and sustainable healthcare operations, there is a clear need to develop a systematic approach to recover, store and repurpose RO reject water from dialysis units to non-potable use within hospital facilities.

Methods

PDSA cycles with three phases: feasibility and safety assessment including baseline water quality tests by accredited laboratory, system pilot and consultation with PUB including design of piping diversion plan and authority clearance, and full implementation with tracking of utility savings and environmental benefits. Group FM shortlisted systems for irrigation, cooling towers, and toilet flushing purposes, ultimately selecting irrigation system due to high water usage, lower implementation cost and shorter turnaround time.

Results

Saving of 9,439m NEWater consumption annually
$12,082 cost savings annually
Total savings can supply up to 50 units of 4-Room HDB flats for a year
First hospital in Singapore to implement this initiative
10% reduction in water consumption in FY24 compared to FY23 (in tandem with other water conservation initiatives)
Annual NEWater consumption reduced from 183,014m (FY23) to 164,691m (FY24)
Annual NEWater cost reduced from $426,065 (FY23) to $403,213 (FY24)

Lessons Learnt

Significant water wastage can be recovered: Up to 70% of water used in dialysis is rejected yet still clean enough for non-potable use. With proper systems in place, a large portion of this water can be reclaimed, reducing the facility's water footprint. Infrastructure limitations need creative solutions: Older facilities may lack dedicated piping or space for storage tanks. Pilot testing builds confidence and evidence: A small-scale test helps identify potential challenges, refine the design, and demonstrate benefits before full-scale rollout. Engagement and clearance from authority bodies such as PUB helps to address concerns and smooth implementation.

Keywords

reverse osmosis, water reuse, sustainability, dialysis, irrigation, environmental, cost savings

Innovators' Details

Connect with this contributor!

Jonson Sofian Teo - jonson_sofian_teo@nuhs.edu.sg

Project Attachment

Optimizing POCT Glucose Testing Frequency in the ED.pdf