Abstract
This study was conducted to investigate the feasibility of use of olivepomace residues and citrus tree wood residues after burning at 550°(olivepomace charcoal and citrus charcoal) as alternative non-traditional substrates in vertical flow wetland systems (VFCWs) for removing inorganic pollutants and organic pathogens from municipal wastewater through secondary treatment for carbon emission reduction to combat climate change. The effectiveness of this treatment was examined by two pilot scale vertical flow constructed wetlands (VFCWs) systems with alternative substrates. Each system was designed from two operated units in series (two stages of treatment), each unit was manufactured with the same design and size. The difference between each system was the substrates used for treatment. The first system included olivepomace charcoal, while the second system included olivepomace charcoal with citrus charcoal. Both models were operated at the same time and under the same conditions. Both systems were tested with seven different hydraulic retention time (HRT) (12-24-36-48-96-144-192 hours). After conducting laboratory tests on wastewater samples after treatment for several biological, physical, and chemical tests, the results indicated that citrus charcoal and olive charcoal are effective alternative substrates in constructed wetland systems. The systemic way test results showed the lowest removal efficiency for TSS, BOD, COD, TP, TKN, and Fecal Coliform (95, 53, 44, 52, 40, and 66% at 12 hr), while the highest removal rates (97, 94, 94, 80, 69, and 98% at 12 hr), respectively in Model 1. And minimum removal rates for TSS, BOD, COD, TP, TKN and Fecal Coliform (95, 34, 22, 42, 48, and 50% at 12 hr), respectively, while the optimal removal (97, 98, 98, 71, 71, and 99% at 12 hr), respectively, in Model 2. This study proved that olive solid waste and tree wood residues are effective alternative substrates in removing pollutants from wastewater, which are inexpensive and environmentally friendly.