ASSESSMENT OF THE PROBLEMS AND MANAGEMENT OF DUMPSITE LEACHATE: IMPLICATIONS FOR SUSTAINABLE LEACHATE MANAGEMENT AT LEMNA DUMPSITE CALABAR, NIGERIA
Author(s): Ekwok Innocent Chigbe; Igelle Evaristus Idaga; David Odey Ushie; Bello Abdulfatai Abiodun; Omubo, Ruth Fingite
Institute(s): 1,3,4,5 Department of Geography and Environmental Science, Faculty of Environmental Sciences, PMB 1115, Calabar, Nigeria; 2 Department of Environmental Management, Faculty of Environmental Sciences, University of Calabar, PMB 1115, Calabar, Nigeria
Volume 5 / Issue 2
Abstract
Dumpsite leachate remains one of the most critical environmental challenges in rapidly urbanizing cities, particularly in developing countries where open dumping persists as a major solid waste disposal method. This study investigated the assessment of the problems and management of dumpsite leachate as an implication for sustainable leachate management at Lemna Dumpsite Calabar, Nigeria. An integrated approach was adopted, combining geophysical surveys, air quality monitoring, and laboratory treatment trials. Electrical resistivity imaging and vertical electrical sounding (VES) were employed to delineate leachate plume migration and assess subsurface contamination. Air quality was monitored over morning, afternoon, and evening periods, focusing on temperature, relative humidity, particulate matter (PM₂.₅ and PM₁₀), formaldehyde, total volatile organic compounds (TVOCs), carbon monoxide (CO), carbon dioxide (CO₂), and hydrogen sulfide (H₂S), benchmarked against World Health Organization (WHO) and Nigeria’s National Environmental Standards and Regulations Enforcement Agency (NESREA) guidelines. Laboratory experiments tested the effectiveness of alum and ferric chloride, with granular biochar, at varying doses to evaluate removal efficiency (RE%) of turbidity, chemical oxygen demand (COD), biochemical oxygen demand (BOD), H₂S, and total coliforms. Geophysical results revealed that the leachate plume extended laterally from 30 m to 70 m and vertically down to 8–12 m, with resistivity values as low as 1.14 Ωm, indicating significant leachate infiltration into both shallow and deep subsurface zones. Air quality analysis showed severe exceedances of safety standards, with PM₂.₅ (126.11 µg/m³) and PM₁₀ (187.60 µg/m³) exceeding WHO limits fivefold and threefold, respectively. Carbon dioxide concentrations (3570.10 ppm) were more than three times the acceptable limit, while H₂S levels (45.35 mg/m³) far exceeded both WHO and NESREA standards, indicating high-risk gaseous emissions from the dumpsite. The Air Quality Level (AQL) classified the site as “very serious” throughout the monitoring period. Treatment trials demonstrated that biochar significantly enhanced the coagulation efficiency of alum and ferric chloride. The optimal performance was recorded at 120 mg/L of either alum or ferric chloride combined with 30 mg/L biochar, achieving maximum removal efficiencies across all tested parameters. Aeration further improved reductions in volatile compounds and microbial contaminants. The findings indicate that biochar-enhanced coagulation be adopted as a cost-effective and sustainable treatment option prior to leachate discharge and on the dumpsite to eliminate odor nuisance in surrounding environments.
Number of Pages: 35
Number of Words: 12476
First Page: 12
Last Page: 46