Sustainable Wastewater Recovery in a Regional Textile Water Utility

Thesis Abstract

The study addresses the escalating water scarcity and effluent management challenges faced by regional textile utilities, where conventional wastewater treatment insufficiently supports reuse while complying with stringent discharge standards. The aim is to evaluate and optimize sustainable wastewater recovery processes within a regional textile water utility to enhance water reuse, recover valuable resources, and reduce environmental footprint. Specific objectives include (1) assessing current wastewater characteristics and variability across production cycles, (2) evaluating the technical and economic feasibility of integrated recovery technologies (e.g., membrane filtration, advanced oxidation, and zero-liquid discharge concepts), (3) developing a decision-support framework using multi-criteria analysis to identify optimal recovery configurations, (4) modeling process performance under operational constraints, and (5) formulating a scalable implementation plan aligned with policy and stakeholder expectations. The study adopts a mixed-methods design underpinned by the Resource-Based View and the Circular Economy Theory to explore technical feasibility and organizational readiness for sustainable recovery. A multimethod data collection strategy is employed. The population encompasses 12 textile production lines within the regional utility, 5 frontline technical teams, and management staff across operations, with a targeted sample of 180 personnel for process and perception surveys. Wastewater sampling occurs monthly over 12 consecutive months from primary, secondary, and tertiary treatment streams, yielding 144 composite samples for physicochemical and microbiological analyses. Instrumentation includes standard methods for chemical oxygen demand (COD), biochemical oxygen demand (BOD), total dissolved solids (TDS), salt concentration, color, turbidity, conductivity, total phosphorus and nitrogen, along with microbial indicators. Process performance data are obtained from plant SCADA logs, energy and chemical consumption records, and maintenance reports. For qualitative insights, 40 semi-structured interviews are conducted with operators, supervisors, and managers, supplemented by 8 focus group discussions with cross-functional teams. Data analysis integrates quantitative techniques—descriptive statistics, time-series analyses, ANOVA and regression modeling to identify drivers of recovery efficiency, and cost-benefit analysis for energy and chemical use—and qualitative methods, with thematic analysis guided by Braun and Clarke to capture barriers and enablers. A techno-economic model combines capital expenditure (CapEx), operating expenditure (OpEx), and life-cycle costs to assess return on investment under three recovery scenarios membrane-assisted filtration, advanced oxidation for organics, and hybrid zero-liquid discharge integration. Sensitivity analyses examine feed variability, energy prices, and policy incentives. Model validation uses historical plant performance data and a cross-validation approach with 20% hold-out samples. Expected findings indicate that targeted membrane filtration combined with selective advanced oxidation can achieve 75–88% recovery of treated wastewater for non-potable reuse, with secondary benefits including reduced salinity buildup and lower sludge generation. The integrated approach is anticipated to reduce net water withdrawal from regional sources by 42–58% and yield a positive net present value within a 7-year horizon under moderate energy price scenarios, with payback periods of 5–6 years for the most feasible configuration. Findings will illuminate significant correlations between operational parameters (flux, trans-mmembrane fouling rate, and chemical dosages) and recovery efficiency, and reveal organizational factors—such as workforce training, operational flexibility, and cross-department collaboration—that condition implementation success. The study contributes to knowledge by delivering a methodological framework for evaluating and designing sustainable wastewater recovery in textile settings, combining a robust techno-economic model with a participatory assessment of operational and organizational readiness, grounded in Resource-Based View and Circular Economy Theory. It advances empirically validated recommendations for selecting recovery technologies, optimizing energy and chemical use, and sequencing deployment across production lines. The main conclusion is that a strategically configured hybrid recovery system, supported by organizational capability building and policy-aligned incentives, can substantially improve water reuse while delivering favorable environmental and economic outcomes for regional textile utilities. Key recommendations include prioritizing membrane-assisted pretreatment for high-COD effluent streams, deploying targeted advanced oxidation for refractory organics, developing operator training programs to sustain performance, establishing monitoring dashboards for real-time decision-making, and pursuing grant funding or tariff-based incentives to accelerate capital deployment. Additional avenues for future research include exploring real-time optimization under dynamic production schedules and extending the framework to similar regional industrial clusters.