Comparing the cost efficiencies of traditional evaporation reduction with PET bottles containing plastic waste

Abstract

The water evaporation largely exhausted reserved water in reservoir. Three formal reduction methods of water evaporation were composed of bio-covering method, chemical and physical methods. Previous studies presented the bio-covering method can reduce the evaporation rate to 15-40% with using natural plant and rarely low expenses. But bio-covering method effected the reduction of water quality and required water quality improvement cost. The chemical method can reduce the evaporation rate to 15-30% and widely use with low expense. In the contrary, chemical method presented the B/C ratio of 1.32, the high unit cost of 7.60 Baht/m³, un-defined covering area and easily defeat by wind and fluctuated temperature. And the physical method can largely reduce the evaporation rate to 70-95% but requiring high expense and complicate installation. In this study, the physical method using PET bottles with waste plastic packed was used. These materials have lower unit cost and commercially found with further reducing waste landfill.  The result presents a dramatically decreasing unit cost of 3.56 Baht/m³ and an increasing B/C ratio of 2.24. Moreover, PET bottles do not contain Diethyl hydroxylamine and Bisphenol A which has a zero environmental impact.