Physicochemical, Elemental, Morphological, and Microbiological Properties of WUPA Sewage Sludge: Implications for Potential Soil Remediation

Abstract

Sustainable management of sewage sludge is a persistent environmental challenge, particularly in rapidly developing areas. This study explores the physicochemical, mineralogical, and microbiological properties of raw sewage sludge from the WUPA Wastewater Treatment Plant, Abuja, Nigeria, to establish the quality of the raw sludge prior to conditioning and to evaluate its suitability for use in soil remediation. Analytical techniques employed comprise Energy Dispersive X-ray Fluorescence (EDXRF) for elemental composition SiO2 has concentration of 67.50wt% as the highest and SeO2 with lowest concentration of 0.00040wt%, Scanning Electron Microscopy (SEM) for morphological analysis result show that carbon (79.00 wt.%, 84.55 atomic%) and oxygen (18.14 wt.%), Fourier Transform Infrared Spectroscopy (FTIR) for functional group identification indicate 3698 to 3265cm-1 assigned to O–H stretching of alcohol and hydroxyl compounds, the band at 1543cm-1 is associated with aliphatic nitro compounds, of medium intensity. The analyzed wastewater sludge had a pH of 6.96 which falls within the optimal range of 6.5-7.0 for plant nutrient availability, indicating it is suitable for agricultural application without pH correction, low salinity, and high organic matter content. Heavy metals such as zinc and copper were within permissible limits of 2.00Mg/l & 0.5Mg/l for liquid sludge. SEM micrographs revealed a heterogeneous, porous structure conducive to soil aeration, while FTIR spectra revealed typical absorption bands of humus substances, including hydroxyl, amide, carboxyl, and aliphatic groups consistent with the presence of humus, which plays an important role in nutrient retention, soil aggregation, and organic matter stability. Microbiological analysis identified potential pathogens, underscoring the need...