Non-potable Water Quality Assessment Methodology for Water Conservation in Arid Climates

Abstract

This paper documents a non-potable water (NPW) quality assessment methodology for a decentralized non-potable water system in Abu Dhabi (AD), capital city of the United Arab Emirates (UAE), which is dominated by sandy and salty soil, high temperature, and humidity. The context is a medical facility case study (MFCS) in AD, which includes a landscape 50% as large as its building footprint. The project identified the need to investigate the impact of air handling unit (AHU) air conditioning (A/C) condensate water (CW) quality on soil health and building hydraulic systems. The aim of the research was to measure the impact of using recycled on-site NPW sources in a MFCS in AD, to alleviate the use of desalinated potable water and reduce associated energy consumption, operation cost, and greenhouse gas emissions for landscape irrigation (LI) and water feature (WF) use. CW has been tested in 2016 and in 2017 and analysed against local authority’s parameter limits to establish suitability for LI and WF use. The findings are that in AD CW classification and characterization is a gap in knowledge whereby salinity and toxicity concentration limits should be addressed by the local authority because CW has an impact on soil infiltration rate due its low dissolved salt content as evidenced by the water test results. The recommendations for this paper are to develop a sustainable water conservation and reuse (SWC) strategy forming the basis for a water protocol by the competent authority for regional medical facility including a methodology for assessing on-site NPW quality for outdoor reuse to reduce soil infiltration problems and consequently conserve water and associated energy. The next steps are to confirm if the MFCS soil infiltration rate is affected by the CW or other factors, and to test additional NPW types.

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

“…The substances measured in the water, as per RSB (2010; 2014) requirements and recommended levels [14] for recycled water and for drinking water, are listed below in Table A1 in Appendix A. The water test results were evaluated against these parameters [25].…”

“…Test one water usage (lpm) = [Flow rate (lpm) × pump run duration (minutes)] × 2 (1) CS1 and CS2 non-potable treatment system enhancement results (diagram), Seguela et al [25].…”