CONSTRUCTED WETLAND DESIGN OPTIMIZATION FOR WASTEWATER TREATMENT

Abstract

Wastewater pollution has recently gained wide attention due to its environmental impact on water bodies. The technological interventions for recycling and nutrient recovery are required to align with sustainable development goal 6. In this regard, aerated vertical flow constructed wetlands (AVFCW) Box-Behnken design (BBD) optimization using RSM methodology served as an innovative technology for the sustainable management of wastewater and resource recovery. This study examines the effect of vertical flow constructed wetlands on the removal efficiency of various physio-chemical and biological parameters. The removal efficiency were 80.1% (COD), 90% (BOD), 94.1% (NH4 +), 94.3% (NO3 -), 73.8% (PO4 -3), and 90.2% (E.coli / fecal bacteria) for AVFCW. Moreover, non-aerated VFCW has 70.3%, 80.21%, 82.1%, 89.9%, 69.8%, and 75.19% removal for COD, BOD, ammonia (NH4 +), nitrate (NO3 -), and phosphate (PO4 -3), and E.coli / fecal bacteria at one day HRT. The results showed that HRT and depth positively affect AVFCW in terms of enhanced treatment performance. Moreover, around 90% of COD, 95% BOD, 100% ammonia, 95% nitrate, 88% phosphate, and 99% E.coli removal were achieved at optimal conditions using variation of HRT, depth, and aeration. The optimal design based on the response surface plot was observed in constructed wetlands having 60 and 90 cm depth and 2-5 days HRT. Thus, optimising environmental and operating conditions and establishing effective maintenance plans are crucial to attain sustainability.