Study of Retention Time Variation on Constructed Wetland Performance for Kitchen Wastewater Treatment

Constructed wetlands are intentionally created systems designed to emphasize specific characteristics of wetland ecosystems to improve landscape, retain stormwater, and enhance its quality. The application of this system has been widely used in several countries as this system is low-cost and sustainable. The treatment performance of constructed wetlands critically relies on the optimal operating parameters, including hydraulic retention time. This prompted the implementation of this study to analyze the effectiveness of retention time variation on constructed wetland performance for domestic wastewater treatment plant. The design of the constructed wetland in this research uses Free Water Surface (FWS) or Surface Flow (SF) system using sand, gravel, and water hyacinth. Domestic wastewater from a local restaurant was used as the sample for this research. The initial kitchen wastewater concentration from the restaurant does not meet the effluent standard by the Ministry of Environment and Forestry Regulation No.68/2016. Data analysis shows a significant decrease in all pollutant parameters after 24 hours of retention time. The initial condition of BOD 1931 mg/L has been reduced to 25.12 mg/L with 98.69% efficiency. The initial condition of TSS 1200 mg/L has been reduced to 29 mg/L with 97.58% efficiency. The oil and grease concentration of 227.5 mg/L has been reduced to 1 mg/L with 99.5% efficiency. At the same time, the initial condition of COD 1356 mg/L has been reduced to 73.29 mg/L with 94.6% efficiency.