Period: July 2024 - ongoing
The escalating global challenge of inadequate sanitation affects billions worldwide, leading to widespread water contamination from untreated fecal sludge (FS) disposal. This issue directly contradicts Sustainable Development Goal 6, which emphasizes safe and improved sanitation and the reduction of untreated wastewater. In Bangladesh, while open defecation has significantly decreased and the use of improved sanitation systems has risen, the management of the generated FS remains a critical concern. With the exception of a small portion of Dhaka, urban areas in Bangladesh rely on on-site sanitation technologies (OSTs) like septic tanks and pit latrines. Studies indicate substantial annual FS production in key municipalities like Khulna, Jhenaidah, and Kushtia. The common practice of discharging untreated sludge into the environment in low-income countries exacerbates public and environmental health issues, contributing to waterborne diseases that disproportionately affect young children. The development of OSTs in Bangladesh has largely overlooked the crucial aspect of managing the accumulated FS. The lack of defined roles among utility service providers and local government institutions further compounds the challenge of establishing effective FSM services in major cities. The environmental and health consequences of improper FS disposal, including pathogen contamination and the spread of diseases, underscore the urgency for sustainable management solutions.
Recognizing the limitations of current disposal methods, research has explored the potential of utilizing FS as a resource in various applications, including animal feed, soil conditioners, fuel sources, and construction materials like cement. The incorporation of waste materials, such as fly ash and granite cutting waste, in brick fabrication has been investigated as a strategy to promote cleaner construction practices and reduce the reliance on clay. However, bricks with a high sludge content often exhibit poor strength and undesirable physical properties. Carbonization of FS at high temperatures presents a promising pre-treatment method to eliminate pathogens and significantly reduce sludge volume, potentially making it more suitable for reuse in brick production. The high absorbance capacity and low bulk density of carbonized FS could contribute to a homogeneous mixture with clay and the production of lightweight bricks. This research proposes to maximize the utilization of carbonized FS in brick production while ensuring standard mechanical strength and porosity levels. This approach aims to stabilize the carbonized FS within building materials, offering a practical application for lightweight bricks in non-aesthetic and unhygienic applications such as drains, embankments, and underground construction. This aligns with the principles of a circular economy by converting harmful waste into a valuable product.
The central objective of this research is to investigate the feasibility of using carbonized fecal sludge as a raw material for brick production. Specific aims include characterizing the physical and chemical properties of carbonized FS (particle size distribution, Atterberg limits, XRF analysis) and evaluating the engineering properties of fabricated bricks containing varying proportions of carbonized FS (compressive strength, water absorption, efflorescence, weight loss on ignition, area shrinkage, SEM analysis, and leaching tests). The expected outcomes include demonstrating the potential of carbonized FS in producing bricks with satisfactory engineering properties, contributing to solid waste management through a waste-to-wealth approach, and creating a novel construction material with potential industrial applications. The project methodology involves collecting and carbonizing FS, mixing it with clay in different ratios, fabricating and firing bricks, and conducting comprehensive laboratory testing to assess their properties and environmental safety. The findings will be compared with conventional bricks, and a preliminary cost analysis for mass production will be conducted. The research is anticipated to provide a sustainable management solution for FS, reduce environmental pollution, and promote the utilization of waste as a valuable resource in the construction industry, particularly for applications where aesthetic appeal is less critical.
