Effect of Forced Aeration and Mechanical Turning on Leachate Quantity and Quality from Glass Cullet Stockpiles

Leachate from mixed glass cullet (crushed recycled glass containers) that is stockpiled before use as construction aggregate or sand substitute is a potential source of water pollution. Rainwater leaching through the stockpiles dissolves and suspends organic compounds and nutrients from the glass. The objectives of this study were to investigate the effect of forced aeration on leachate quantity and quality in the glass cullet stockpiles compared to mechanical turning/mixing. Three experimental stockpiles were set up in the field, two with forced aeration treatment (one with fine and the other with coarse cullet) and one (coarse cullet) with mechanical turning. The organic concentrations in the leachate in most cases were comparable to those of raw domestic wastewater. Organic constituents (e.g., ${\text{BOD}}_5$ ) were reduced $\text{by}>70\mathrm{\%}$ from the initial levels $\left(\sim 450\text{mg}{\text{L}}^{-1}\right)$ during a 1.5-month period with forced aeration, compared to an 85% decrease in the turned stockpile. Particle size affected temperature and oxygen levels under aeration conditions, resulting in more biodegradation of organic contaminants in the stockpile of coarse cullet than the fine cullet.