Experimental investigation of different denim washes on stones, denim fabric and effluent discharge

Abstract

Purpose – This study aims to investigate the deterioration of pumice stones during denim washing processes, including acid, enzyme and bleach washes, with a focus on the impact of stone size (small, medium and large) on denim fabric aesthetics and performance. It also checks whether it is possible to reuse pumice stones and how they affect the quality of the fabric and the effluent by looking at things such as turbidity, total dissolved solids (TDS) and total suspended solids (TSS). This research seeks to optimize stone selection to enhance sustainability in denim washing while minimizing environmental impacts. Design/methodology/approach – Several parameters were investigated to understand the effects of different stone wash processes on denim fabric and effluent quality. Fabric parameters included weight (g/m2), tensile strength, color fastness, shrinkage and colorimetric values (L*, a* and b*), which varied based on stone size and wash type. In addition, effluent quality assessments focused on TDS, TSS, turbidity and pH levels. Stone properties such as porosity, hardness and compressive strength were also measured to evaluate the impact of repeated washes and stone erosion on wash effectiveness. Findings – This study reveals that small stones in acid washes increase fabric GSM, whereas large stones in enzyme and bleach washes reduce tensile strength and enhance the vintage appearance of denim. Bleach washes lead to higher TDS levels, and the reuse of pumice stones raises TSS and turbidity. However, enzyme washes with reused stones demonstrate superior results in terms of fabric aesthetics and properties. These findings emphasize the importance of optimizing stone selection to enhance denim washing outcomes while minimizing environmental impacts. This research recommends that enzyme-washed stones can be safely reused up to three times, ultimately reducing raw material costs by 33%. Originality/value – This study evaluates denim washing processes on pumice stones, effluent quality and washed stretch denim fabric. It explores reusing pumice stones, offering cost reduction and sustainable practices. The methodology reveals the relationship between stone properties, wash outcomes and environmental effects.