Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Engineering Science

Program

Chemical and Biochemical Engineering

Supervisor

Dr.Franco Berruti

2nd Supervisor

Dr. Domenico Santoro

Co-Supervisor

Abstract

Hydrogen sulfide (H₂S) emissions in sewers pose persistent odor issues and significant challenges for wastewater management systems. This study investigates the potential of biochar derived from drinking water alum and iron sludge as a sustainable, cost-effective alternative to conventional iron-based sulfide control methods. Two-phase material adsorption screening tests were conducted using deionized water-sulfide solution and secondary wastewater-sulfide solution. In the first phase, biochars demonstrated superior performance over non-pyrolyzed sludge, achieving sulfide removal rates exceeding 95%. The second phase revealed that iron sludge biochar produced at 500°C outperformed other materials in sulfide adsorption across various pH levels (8, 9, and 12), exhibiting a remarkable adsorption capacity of 182 mg/g. To evaluate practical applicability, a lab-scale sewer model with a recirculation system was developed, accurately simulating full-scale sewer conditions. This model serves as a proof of concept, laying the foundation for future studies to assess these alternative materials for sulfide odor control in more realistic sewer environments.

Summary for Lay Audience

Hydrogen sulfide (H₂S) is a gas produced in sewer systems that causes strong, unpleasant odors and can be harmful to health. Traditionally, cities use chemicals like iron salts to control this gas, but these chemicals have become more expensive over time. This research looks at using waste materials, specifically drinking water alum sludge and drinking water iron sludge, as cheaper alternatives to manage H₂S in sewers. Drinking water alum sludge and drinking water iron sludge are waste by-products from water treatment plants. In this study, these waste materials were turned into biochar, a type of charcoal that can absorb hydrogen sulfide. The research involved evaluating this biochar in both deionized water and actual wastewater sulfide solutions to see how well it could remove the sulfide. To make sure these tests were realistic, we also worked on mathematical based analysis of a real sewer and develop a design strategy for a scaled down model. This model was designed to closely mimic the conditions of a real sewer, including how wastewater flows and how bacteria interact within the sewers. The model will be valuable for future experiments in understanding how the alum and drinking water iron sludge biochar would perform in real-world sewer conditions for sulfide removal. The results from the adsorption experiment showed that biochar made from alum and drinking water iron sludge could be a suitable alternative to the expensive iron salts currently used for controlling sewer odors. This approach is also environmentally friendly because it repurposes waste materials, turning them into something useful. Overall, this study helps to move towards more sustainable and cost-effective ways to manage wastewater and control unpleasant odors in urban areas.

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