Co-composted faecal sludge as organic fertilizer to restore crude oil- contaminated soil

Abstract Several developmental challenges, including natural resource depletion, environmental degradation, solid waste management, and the dumping of untreated faecal sludge into the environment, are issues facing developing countries and damaging their economic well-being. Crude oil pollution of arable land and water resources concerns several oil-producing communities whose land is degraded daily by oil spills. Although it contains nutrients and organic matter needed for improved plant growth, Faecalwaste poses a severe environmental concern as it also has pathogens. Co-composting is considered a reasonable, low-cost waste treatment option that can allow the recycling of faecal sludge and other organic wastes from various waste streams with the double advantage of combined sanitation, nutrient recovery, and income generation. This work developed a biostimulant for crude oil-polluted soil remediation using dewatered faecal sludge co-composted with organic kitchen waste. By mixing dewatered faecal sludge with organic kitchen waste using structural material (sawdust) as a bulking agent in a co-composting process, a sanitised compost devoid of enteric pathogens was produced. The composting product's quality was assessed by monitoring the composting system's physicochemical parameters. The reduction in faecal indicators was remarkable using sawdust matrix as a structural material, and T.N., T.P., T.K., and C: N ratios were all significant. These results showed the feasibility of co-composting dewatered faecal sludge with kitchen waste and sawdust as a matrix to generate compost usable in agriculture and crude oil-contaminated soil remediation.