Non-Potable Water Quality Assessment Results for Water Conservation in the Context of a Medical Facility Case Study

Abstract

This paper discusses recycled non-potable water (NPW) quality test results from an existing, decentralized, treated air handling unit (AHU) air conditioning (A/C) condensate water (CW) system in a medical facility case study (MFCS) in Abu Dhabi (AD), the capital city of the United Arab Emirates (UAE). The MFCS, a 364-bed hospital that opened in 2015 with 50% landscaping, is targeting 100% non-clinical/non-potable water use for landscape irrigation (LI) from 179,700 m3/year treated CW, which is a by-product of AHU A/C. For seven months per year, however, a deficit of 14,340 m3 AHU A/C CW occurs, so costly and non-sustainable, desalinated potable water is required. The proposed change project, using a mixed methodology, develops a sustainable NPW strategy, including a protocol to extract water from recycled, onsite, organic food waste, fire sprinkler pump test water (FSPTW), and reverse osmosis reject water (RORW) to meet the AHU A/C CW shortfall by adapting, enhancing, and monitoring the medical facility’s NPW treatment system. The hospital’s sustainability strategy implemented by the author could be legislated and mandated by the relevant authority for regional medical facilities, taking the form of a water conservation protocol including the classification and characterization of different types of NPW to understand their impact on LI, human health, and building water systems. The outcome is a novel change in practice to reuse 25,141 m3/year RORW and 1136 m3/year FSPTW as makeup water for the A/C CW shortfall in winter. The results identify key considerations to be addressed by the target audience (building owners, landscape contractors, and facility managers) when reusing NPW to protect the environment against soil degradation—a major aspect of decarbonization.