Department of Community Health, Faculty of Clinical Sciences, Obafemi Awolowo University, Ile Ife, 234036, Nigeria; University of Ibadan, Ibadan, Nigeria
Aluko, O.O., Department of Community Health, Faculty of Clinical Sciences, Obafemi Awolowo University, Ile Ife, 234036, Nigeria; Sridhar, M., University of Ibadan, Ibadan, Nigeria
The removal of pollutants in landfill leachate was investigated using constructed wetlands, a trickling filter, alum flocculation and coagulation, and a sequencing batch reactor in various combinations. Thirteen combined operations were investigated involving three out of the four unit treatment methods in series. The study was conducted because unit operations, though achieved reductions in pollutants concentrations had effluent values above the national regulatory guideline values. The suspended solids of effluents were permissible in most treatment processes, while reductions in 5-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and ammonia (NH3) of leachates ranged from 80% to 97%; 86% to 97% and 92% to 98% respectively. However, there were significant increases in nitrate (85%) and dissolved oxygen of treatment (218%). In addition, the characteristics of the recommended treatment sequence, involving constructed wetlands, alum and trickling filter produced effluents with reductions in colour (97%), alkalinity (97%), BOD (97%), COD (97%) and NH3 (98%), and in metals, except nickel (29% reduction from the influent values). The recommended treatment combination is suitable for effective leachate management at the landfill. The cost of constructing and operating the recommended treatment combination at the facility, for 5 years, would be NGN6,009,750.00 ($38,036.39). The performance should be monitored on site prior to full adoption if effluent characteristics remain consistently low over dry and wet seasons. © The Author(s) 2013.
Combined treatment; Effluent quality; Landfill leachates; Nigeria; Regulatory standards; Biochemical oxygen demand; Filters (for fluids); Pollution; Water quality; Wetlands; Leachate treatment; ammonia; dissolved oxygen; ground water; nickel; nitrate; biochemical oxygen demand; chemical oxygen demand; coagulation; constructed wetland; cost-benefit analysis; dissolved oxygen; effluent; flocculation; landfill; leachate; monitoring; nitrogen compound; pollutant removal; waste treatment; alkalinity; article; bioaccumulation; biochemical oxygen demand; chemical oxygen demand; constructed wetland; effluent; Ipomoea aquatica; landfill leachate; Nigeria; nonhuman; priority journal; sequencing batch reactor; suspended particulate matter; trickling filter; waste component removal; water contamination; Ibadan; Nigeria; Oyo; combined treatment methods; discharge regulatory standards; effluent quality; Landfill leachate; Nigeria; Ammonia; Biological Oxygen Demand Analysis; Bioreactors; Nigeria; Nitrates; Water Pollutants, Chemical; Water Pollution; Water Purification; Wetlands