Dynamics in Physicochemical and Bacteriological Properties of Simulated Leachate from Dump Site Soil in Ikhueniro, Benin City, Edo State, Nigeria

Abstract

Study’s Excerpt • The physicochemical and microbiological properties of leachate from municipal solid waste (MSW) in Ikhueniro, Edo State, Nigeria was investigated. • Results revealed significant correlations between bacterial counts and the degradation of organic matter. • There is a need for improved waste management strategies in the area. Full Abstract Municipal solid waste (MSW) management in Nigeria faces significant challenges due to rapid urbanization and poor waste management practices. Leachate, the liquid generated from MSW, poses a major pollution threat to natural resources, including surface and groundwater, and adversely affects human health and hygiene. This study investigated the dynamics in physicochemical and microbiological properties of simulated leachate from dump site soil in Ikhueniro, Edo State, Nigeria using standard Microbiological testing techniques. Samples were collected from a non-sanitary open dumpsite in Ikhueniro, Edo State, Nigeria, and leachate was obtained by filtering 150 g of waste-impacted soil mixed with sterile distilled water (1000 mL). Over 28 days, microbial detection enumeration and physicochemical characterization were conducted on the filtrate leachate sample maintained in a rotary shaker at 28 °C and 150 rpm. Results indicated high densities of microbial contamination with total heterotrophic bacteria (1.5±0.5 to 6.9±1.0 × 104 CFUmL-1) and coliform (2.7±0.8 to 7.8±1.0 × 103 CFUmL-1) counts. These included potential pathogens like Klebsiella spp., Salmonella spp., Bacillus spp., Pseudomonas spp., and Yersinia spp. Physicochemical analyses revealed significant (p<0.05) variations in parameters such as electrical conductivity (EC) with values ranging from 9183.3 – 9758.7µscm-1, total dissolved solids (TDS) with values ranging from 7004.0 – 8210.3 ppm, with changes in pH ranging from 6.48-7.62, biochemical oxygen demand (BOD) with values ranging from 561.7 – 651.3 mgL-1, and chemical oxygen demand (COD) with values ranging from 1981.7-2058.7 mgL-1. The pH dropped from 7.62 to 6.48, and the levels of BOD and COD indicated a decreasing trend that was strongly and positively correlated (“r” ranging from 0.949 to 0.968) with bacterial counts, indicating organic molecule degradation. This study underscores the environmental and public health risks posed by improperly managed waste and its resultant leachates while highlighting the potential for bioremediation strategies using isolated bacterial species. Furthermore, transitioning to sanitary landfills and improving waste management practices are crucial for mitigating these risks.

Keywords

• leachate
• microbial occurrence
• physicochemical changes
• open-dumpsite
• municipal solid waste