Application of constructed wetlands to the treatment of leachates from a municipal solid waste landfill in Ibadan, Nigeria.
Leachates are wastewater generated principally from landfills and solid waste disposal sites. Leachates emanating from municipal wastes are a major source of surface and groundwater pollution worldwide. Globally, leachates have been implicated in low yield of farm produce, developmental anomalies, low birth weights, leukemia incidence, and other cancers in communities around the site. They have also been implicated in hazards to the environment, loss of biodiversity, and contamination of water sources. At Aba-Eku in Nigeria, leachates are being discharged into the Omi Stream without treatment. A study was conducted on a method of leachate treatment that passes the leachate through constructed wetlands using Ipomoea aquatica (Forsk), a locally available plant found close to the landfill site. The aim of the study was to evolve a sustainable and cost-effective method of treatment whose effluents can be discharged into the Omi Stream with no or minimal impact. The study was descriptive and analytical in design. Samples were collected and analyzed with standard methods for pH, suspended solids (SS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammonia, nitrate, and trace metals. Raw leachates were turbid and amber in color and contained suspended solids (197.5 mg/L), ammonia (610.9 mg/L), lead (1.64 mg/L), iron (198.10 mg/L), and manganese (23.20 mg/L). When the leachates were passed through the constructed wetland with eight hours' detention time, effluents showed significant reductions in suspended solids (81.01 percent), BOD (86.03 percent), and ammonia (97.77 percent). The study shows that a constructed wetland is a feasible tool for the treatment of leachates before their disposal into the environment in Nigeria and can help safeguard environmental quality.
Department of Epidemiology, Medical Statistics and Environmental Health, Faculty of Public Health, College of Medicine, University of Ibadan, Oyo State, Nigeria. ooaluko@yahoo.com
Olufemi Oludare
OO
Aluko
M K C
MK
Sridhar
D000641:Ammonia / Q000032:analysis; D001673:Biodegradation, Environmental; D027741:Ipomoea / Q000378:metabolism*; D019216:Metals, Heavy / Q000032:analysis; D009549:Nigeria; D009566:Nitrates / Q000032:analysis; D010710:Phosphates / Q000032:analysis; D012037:Refuse Disposal; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
D019216:Metals, Heavy; D009566:Nitrates; D010710:Phosphates; D014874:Water Pollutants, Chemical; D000641:Ammonia