Impact of the Organic Strength of Dairy Wastewater and Vermibed Depth on the Performance of Macrophyte-Assisted Vermifilters

Abstract

In the last few decades, vermifiltration has become a well-known alternative to conventional wastewater remediation methods owing to its economic viability and environmental sustainability. In the present study, we examined the effect of the organic strength [i.e., chemical oxygen demand (COD)] of an influent (i.e., synthetic dairy wastewater) and the depth of the vermibed on the performance of a macrophyte-assisted vermifilter (MAVF), in terms of organic-carbon and nitrogen removal. The to-date inadequately explored possible N-removal pathways in the designed MAVF system were also investigated. The designed MAVF, with its vertical subsurface flow, achieved maximum COD removal up to 96.5 ± 1.5% when the influent COD and vermibed depth were at 1,400 ± 89 mg/L and 20 cm, respectively. Similarly, the MAVF produced a significant reduction in the ammonium–nitrogen (