Implementation of a full-scale constructed wetland to treat greywater from tourism in Suluban Uluwatu Beach, Bali, Indonesia

Abstract

This original research examines a full-scale subsurface Constructed Wetland (CW) system in Indonesia, where most CW research has been limited to laboratory scale experiments. The CW system was located in Bali and built in 2015 in a single series formation. This study aims to demonstrate the performance of the system in treating greywater and examine the nutrient content plants’ above-ground biomass. The CW was arranged in linear sequence composed of one unplanted (CW1) and five planted treatments of Iris pseudacorus (CW2), Caladium bicolor (CW3), Rhoe discolor (CW4), Sansevieria trifasciata (CW5) and Heliconia psittacorum (CW6). There has been little research on Caladium bicolor, Rhoe discolor and Sansevieria trifasciata in a full-scale CW application. Our results showed fluctuating efficiency (%) in the reduction of Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solid (TSS), Oil and Grease (O&G), Nitrate and Phosphate. The highest removal efficiency for CW1, CW2, CW3, CW4, CW5, CW6 were O&G (63.63%), BOD (90.66%), Nitrate (83.55%), BOD (80%), BOD (82.88%) and Phosphate (89.93%) respectively. After the experimental period, S. trifasciata and H. psittacorum experienced a decrease in Total N concentration, while H. psittacorum experienced a decrease in phosphate in above-ground biomass. Species of R. discolor, C. bicolor and I. pseudacorus showed good performance in terms of their growth and development. Although high removal efficiency was observed at certain times, this study showed the negative removal efficiencies at times among parameters as a consequence of the low Hydraulic Retention Time (HRT) and high Hydraulic Loading Rate (HLR).