Study on the performance of horizontal sub-surface flow using constructed wetland system for treatment of wastewater

Abstract

Horizontal constructed wetlands (HCWs) are an innovative and sustainable technology for wastewater treatment that harness natural processes to improve water quality. HCWs are engineered systems designed to replicate natural wetland functions, utilizing a horizontal flow of wastewater through a planted bed of gravel or soil. The primary mechanisms involved include physical filtration, microbial degradation, and plant uptake. This abstract outlines the principles of HCWs, their design considerations, and their effectiveness in treating various types of wastewater, including municipal, industrial, and agricultural effluents. Key factors such as substrate characteristics, plant species selection, and hydraulic loading rates significantly influence performance. HCWs offer several advantages, including low operational costs, energy efficiency, and ecological benefits. India generates approximately 62 billion liters of wastewater daily, derived from both urban and rural domestic sources, as well as industrial activities. The total installed capacity of wastewater treatment plants (WWTPs) in India is about 50 billion liters per day. Currently, approximately 30-35% of the total wastewater generated is treated. This means that a significant portion of wastewater either remains untreated or inadequately treated, posing environmental and public health challenges. To develop energy efficient constructed wetland technology for in-situ treatment of wastewater flowing through out-fall drain and to study different criteria and variables of the treatment unit for arriving at the design guideline a bench scale study on performance of Horizontal Subsurface Constructed Wetland was collected. A rectangular shape tank was fabricated with glass dimension 30cm ×18cm × 18cm as the experimental model. Wastewater was collected from Jadavpur University campus. The different flow rates with variable time was maintained by the tap. After different retention time the water was collected for laboratory analysis of different wastewater quality parameter. The experiment was carried with the ‘canna indica’ plant. From the bench scale model study analysis of constructed wetland, it showed that the removal efficiency of Turbidity (NTU)-57.41%, TSS (mg/L)-76.47 %, Nitrate (mg/L)-65.71 %, Nitrite (mg/L)-22.95 %, Phosphate (mg/L)-99.1 %, TKN (mg/L)-81.03 %, DO (mg/L)-27.14 %, BOD (mg/L)-79.12 %, COD (mg/L)-82.62 %, Total Coliform (MPN/100 ml)-61.11 %, Fecal Coliform (MPN/100 ml) -72% respectively. According to the removal efficiency of wastewater quality parameter it showed good performance.