A Quantitative Feasibility Model for Singapore Waste-to-Energy Ash as a Zeolitic Material Feedstock

Pratham Gaurav Tewari 

In Singapore’s waste management system, waste-to-energy ash is a major by-product but is viewed as a residue to be managed rather than a material resource. This paper examines whether Singapore waste-to-energy ash could be used as a feedstock for zeolitic material synthesis, when assessed through a quantitative feasibility model rather than a descriptive review. In this study a mathematical framework is developed based on five criteria - technical suitability, environmental safety, scalability, cost plausibility, and circular resource value. The model also includes two threshold conditions and a nonlinear penalty for impurity or risk burden. This ensures that feasibility is treated as a constrained and a multi-factor problem rather than a general sustainability claim. The aim of this paper is not to prove from scratch that ash-to-zeolitic conversion is scientifically possible, as supported in the wider literature, instead this paper assesses if this pathway is realistic in the Singapore context. The baseline model produces a feasibility score of F = 0.351, indicating qualified but constrained feasibility. Sensitivity analysis produces scores between F = 0.323 and F = 0.382 under plausible variations in model assumptions, while stricter technical or environmental threshold conditions reduce the feasibility score to F = 0. By shifting focus on Singapore-specific implementation feasibility from general scientific possibility, the paper positions ash-valorisation as a higher-value circular materials question rather than only a waste management issue. The results indicate that such a pathway represents a credible but condition-dependent higher-value ash-valorisation option, rather than an immediate alternative to current reuse approaches.