Synthesis and Optimization of a Water Network Scheme for a Multipurpose Multiproduct Textile Dyeing Facility: An Industrial Case Study

Abstract

The textile industry plays a critical role in global economic and social development as it provides essential goods and employment to millions worldwide. However, it is also among the most environmentally taxing industries, characterized by intensive water consumption and significant wastewater emissions. These challenges not only contribute to severe environmental degradation but also pose significant risks to public health due to the toxic substances released into water bodies. Traditional end-of-pipe solutions, which treat wastewater after it is generated, offer limited relief and incur considerable financial and operational costs, making them unsustainable in the long term. The growing urgency to address these issues has highlighted the importance of process integration, which takes a holistic approach by optimizing resource use within the production system in order to reduce waste and improve efficiency at the source. Thus, process integration offers a transformative pathway to address water-related challenges of the textile industry by implementing strategies such as direct and indirect water reuse, recycle, and regeneration. This work presents a Mixed Integer Non-linear Programming model for the optimization of both water usage and makespan in a multipurpose multiproduct textile dyeing process. The proposed approach integrates production scheduling with wastewater minimization within a simultaneous optimization framework with the aim of reducing freshwater consumption and wastewater generation while maintaining minimal impact on production schedules. Key factors such as product demand, water requirements, and wastewater generation are incorporated to design a sustainable water management strategy that balances operational, economic, and environmental constraints. The computational feasibility of the framework was validated using advanced solvers such as CONOPT3 and DICOPT. However, the integration of water reuse into production scheduling introduced significant complexity, particularly for larger scenarios. An industrial case study was used to demonstrate the applicability of the proposed model. Results revealed significant water savings of up to 60.4% within the water network, with a manageable 77-minute deviation from the optimal makespan. These results underscore the effectiveness of a unified approach in identifying and utilizing water reuse and recycling opportunities while maintaining production schedules with minimal disruption. This highlights the model's potential for sustainable and efficient water management in industrial processes.