Comparison of Vertical and Horizontal Subsurface Constructed Wetland for Water Pollutant Reduction of Brantas River

Abstract

Improving the water quality of the Brantas River can be achieved by implementing nature-based technology by using the Brantas River as a raw water source for clean water. In this research, subsurface flow constructed wetlands, which include vertical subsurface constructed wetlands (VSSFCWs) and horizontal subsurface constructed wetlands (HSSFCWs), are used as a sustainable and low-cost approach to improve water quality. The VSSFCW system is configured with a layer of gravel substrate, Heliconia psittacorum, and a layer of activated carbon. The configuration for the HSSFCW system is also similar but without the activated carbon layer. This research aimed to determine the quality of the post-treatment water using CWs as an eco-garden to reduce pollutants from the Brantas River. Measurement of water samples from the reactor with laboratory-scale dimensions at the Environmental Laboratory of the State University of Malang, where water samples were taken from the Dam Kadalpang, Brantas River. These measurements were made on physicochemical parameters such as pH, DO, temperature, conductivity, salinity, turbidity, TDS, BOD, and COD. There were four observation points in this research, namely VSSFCW with Heliconia psittacorum and control VSSFCW without plants, where both were given an activated carbon layer, as well as HSSFCW with Heliconia psittacorum and control HSSFCW without plants. The results of data analysis showed that both CWs systems with plants were able to reduce turbidity up to 99% and BOD with a performance efficiency reaching 89%. Both systems also removed COD with a removal efficiency of 73%. TDS was also reduced in both CWs, although there was no significant difference. Similar results were obtained in conductivity and salinity. The pH, temperature, and DO conditions at each observation point met the quality standards and recommendations of previous studies, which became one of the factors supporting the reduction performance of the VSSFCW system. The pollutant degradation capability of the CWs system shows that it can reduce pollutants in the water and it is suitable for use as raw water in the production of clean water.