Performance of small and large scales rainwater harvesting systems in commercial buildings under different reliability and future water tariff scenarios

Nor Hafizi Md Lani; Achmad Syafiuddin; Zulkifli Yusop; Umussaa'dah Binti Adam; Mohd Zaki Bin Mat Amin

doi:10.1016/j.scitotenv.2018.04.418

Performance of small and large scales rainwater harvesting systems in commercial buildings under different reliability and future water tariff scenarios

Sci Total Environ. 2018 Sep 15:636:1171-1179. doi: 10.1016/j.scitotenv.2018.04.418. Epub 2018 May 9.

Authors

Nor Hafizi Md Lani¹, Achmad Syafiuddin², Zulkifli Yusop³, Umussaa'dah Binti Adam⁴, Mohd Zaki Bin Mat Amin⁵

Affiliations

¹ Department of Water and Environmental Engineering, Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia.
² Department of Water and Environmental Engineering, Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia; Centre for Environmental Sustainability and Water Security (IPASA), Research Institute for Sustainable Environment, Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia.
³ Department of Water and Environmental Engineering, Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia; Centre for Environmental Sustainability and Water Security (IPASA), Research Institute for Sustainable Environment, Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia. Electronic address: zulyusop@utm.my.
⁴ Resource Sustainability Research Alliance, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia.
⁵ Water Resources and Climate Change Research Centre, National Hydraulic Research Institute of Malaysia (NAHRIM), 43300 Seri Kembangan, Selangor, Malaysia.

PMID: 29913579
DOI: 10.1016/j.scitotenv.2018.04.418

Abstract

A rainwater harvesting system (RWHS) was proposed for small and large commercial buildings in Malaysia as an alternative water supply for non-potable water consumption. The selected small and large commercial buildings are AEON Taman Universiti and AEON Bukit Indah, respectively. Daily rainfall data employed in this work were obtained from the nearest rainfall station at Senai International Airport, which has the longest and reliable rainfall record (29 years). Water consumption at both buildings were monitored daily and combined with the secondary data obtained from the AEON's offices. The mass balance model was adopted as the simulation approach. In addition, the economic benefits of RWHS in terms of percentage of reliability (R), net present value (NPV), return on investment (ROI), benefit-cost ratio (BCR), and payback period (PBP) were examined. Effects of rainwater tank sizes and water tariffs on the economic indicators were also evaluated. The results revealed that the percentages of reliability of the RWHS for the small and large commercial buildings were up to 93 and 100%, respectively, depending on the size of rainwater tank use. The economic benefits of the proposed RWHS were highly influenced by the tank size and water tariff. At different water tariffs between RM3.0/m³ and RM4.7/m³, the optimum PBPs for small system range from 6.5 to 10.0 years whereas for the large system from 3.0 to 4.5 years. Interestingly, the large commercial RWHS offers better NPV, ROI, BCR, and PBP compared to the small system, suggesting more economic benefits for the larger system.

Keywords: Economic benefit; Non-potable use; Rainfall; Roof area; Tank size.