testing the effectiveness of different soil media in batch-operated lab-scale horizontal subsurface flow constructed wetlands for wastewater treatment using twin-hearth furnace slag

This study evaluates the effectiveness of twin-hearth furnace slag (thfs) combined with local soils (entisols, inceptisols, alfisols, and vertisols) as substrates in horizontal subsurface flow constructed wetlands (hsfcws) for domestic wastewater treatment. both planted and unplanted cws were tested, with canna indica and typha latifolia used as macrophytes. the experimental setup involved a hydraulic retention time (hrt) of 48 hours, with a 50:50 mixture of soil and thfs used in each cw. the results indicated significant removal efficiencies (re) for various wastewater parameters, including bod5 (78.7%), cod (85.3%), nitrate nitrogen (90.2%), and soluble reactive phosphorus (95.5%) in planted cws. unplanted cws also showed notable treatment performance. the study concluded that the combination of thfs and soil in cws effectively meets the effluent standards set by the central pollution control board (cpcb) and the world health organization (who). the findings suggest that slag-based cws, with or without plants, offer a promising, low-cost solution for wastewater treatment, particularly in tropical regions.