Characterization and Utilization of Sludge from a Wastewater Treatment Plant for the Production of Organo-mineral Fertilizer

Abstract

There is a global crusade for increased agricultural production to alleviate food security challenges due to the
expanding world population. The growing population in Nigeria, contributes to increase in the volumes of sewage
sludge wastes generated. Sludge are created when wastewater is treated and a large amount of the nutrients
accumulate in the sludge. Many studies focus on basic chemical properties but lack deep analysis of micro- and
macro-nutrients and heavy metal determination. This research investigated the production of an organo-mineral
fertilizer by combining sewage sludge from a wastewater treatment plant with chemical fertilizer. The
experimental approach involved collection and processing of sewage sludge, formulation and characterization of
organo-mineral fertilizer. The moisture content was 21.5% - 35.7%, pH (4.0-8.2), total organic matter (22.2-
50.0%), bulk density (1.0-2.1g/cm3) and water holding capacity (42.0-54.5 g water/g dry sample). The chemical
composition shows the presence of K2O (5.49-10.27%), P2O5 (18.27-35.30%) and N (4.99-9.26%). Other elements
present are Ca (4.61-33.89 g/kg), Mg (4.61-18.86 g/kg), Zn (0.91-5.0 g/kg) and Fe (8.28-10.97 g/kg). The findings
highlight the importance of sludge-based organo-mineral fertilizer in reducing reliance on synthetic fertilizers
while providing an effective waste management solution. The results also demonstrate that sludge from water
treatment plants is a potential candidate for formulating organo-mineral fertilizer for use in crop production.