Mixed contaminants: Occurrence, interactions, toxicity, detection and degradation

The present study investigates the potential of Municipal Solid Waste Incinerator Bottom Ash (MSWI-BA) collected from a waste-to-energy conversion plant in Delhi for geoenvironmental applications. The physicochemical and geotechnical properties of freshly quenched MSWI-BA were examined for cement-stabilized specimens with varying cement content ranging from 3% to 9%. The study aimed to assess the influence of pH and metal(loid)s concentrations during the standard curing period. The results demonstrated that adding cement formed C-S-H and C-A-H gel and Ca-hydrates within the matrix of 28-day cured samples. Specimens with 7% and 9% cement content exhibited the presence of quartz, calcite, belite, and other strength-enhancing compounds, leading to significant improvements in unconfined compressive strength and California bearing ratio values by up to 119.37% and 96.42%, respectively. Thermogravimetric analysis indicated moisture loss and breakdown of aluminates and silicates caused cracking at temperatures above 720 °C. The incorporation of cement resulted in the encapsulation of heavy metals, with the concentrations of Zn and Cu remaining within permissible limits. This study confirms the applicability of cement-stabilized MSWI-BA for flexible road pavements, earth fills, and various geoenvironmental applications.