Utilization of an Innovative Solar-Powered Desalination System for Treating Saline Drainage Water at the American University of Baghdad Site

Introduction

Maintaining sufficient quantities of potable water for humanity is a primary concern for scientists. This is because water is the second most essential element for life, after air. Consequently, numerous desalination technologies exist, such as reverse osmosis (Zhang et al., 2020), electrodialysis (Sano et al., 2018), dehumidification (Abdullah et al., 2018; Abdullah et al., 2020a), multi-stage flash distillation (Lv et al., 2019), multi-effect boiling (Darwish et al., 2006), vapor compression (Wu et al., 2019), seawater greenhouse units (Essa et al., 2020b), and solar stills (Essa et al., 2020a). Solar stills are small-scale desalination units that can be used to meet the freshwater needs of small households due to their low yield. Researchers have attempted to modify conventional solar stills to increase the yield of freshwater distillates (Bait, 2019; Phadatare and Verma, 2007; Xiao et al., 2013). Therefore, these modifications included a solar distillation wick (Omara et al., 2016), a graded solar still (Essa et al., 2019; Velmurugan et al., 2009), a tubular solar still (Elshamy and El-Said, 2018), a corrugated solar cutter (Omara et al., 2016; Omara et al., 2015), solar trays (Abdullah et al., 2020b), and solar stationary discs (Essa et al., 2020c).

Despite the abundance of renewable energy resources in Iraq, the use of solar energy in power generation and water desalination applications is still in its technological and economic infancy. Significant potential exists, yet the development of many sustainable energy applications in Iraq is very slow. This paper presents a complementary study to one previously submitted to the American University of Baghdad regarding the utilization of drainage water on the university campus and its conversion into potable water for domestic use. This study presents an innovative, low-cost, and high-productivity method for water desalination, provided the study is adopted and an integrated plant is established near the drainage water source.

Details of the study concept:

A new wick operating mechanism was proposed for a pyramid-shaped solar distillation system. The existing solar wick wire (CWSS) still has a parallel upper basin liner with several slits 3.0 cm above the original basin liner. This liner is covered with jute wick wire, with wick wires hanging from the liner slits to draw water from the basin and keep the wick surface constantly moist through capillary action. The proposed system improves the wick operating mechanism in the solar distillation system because the wick wires draw an amount of water equal to the amount of evaporated water, without increasing or removing hot water. Different numbers of wick wires—9, 16, 25, and 35 wires—were tested. Additionally, external and internal mirrors were used to enhance the thermal energy input of the solar trains. Furthermore, the effect of vapor withdrawal from the CWSS to be condensed in the internal and external refrigeration cycle was studied.