Water scarcity is an escalating global concern, particularly in urban areas where growing populations and increased domestic water use strains the limited freshwater resources. Greywater, which constitutes a significant portion (50- 80%) of household wastewater, offers valuable opportunity for reuse. This study determines the potential of greywater, treated with hybrid treatment system comprising of constructed wetland technology followed by ozonation, as an alternative to freshwater in textile dyeing process. Laboratory-scale vertical flow constructed wetland planted with Canna Indica followed by ozonation was employed for greywater treatment. The experimental setups were designed: planted, planted Vertical Flow Constructed Wetland (VFCW) with ozonation and unplanted VFCW serving as a control. Parameters including pH, electrical conductivity (EC) and temperature were measured using a multimeter. Total Suspended Solids (TSS) and Total Dissolved Solids (TDS) were measured using the gravimetric method. The 5-days Biological Oxygen Demand (BOD5), phosphate and E. coli were analyzed by the standard methods of American Association of Public Health Administration (APHA) (2005). After both VFCW and Ozonation treatments, the combined treated greywater was used in textile wet processing as it aligned with the World Health Organization (WHO) Guidelines for the safe use of wastewater, excreta and greywater (2006). Batch fabric samples of selected reactive dyes were prepared by using treated domestic greywater in dyeing and washing stages of textile dyeing process while the standard fabric samples were dyed by using conventional tap water in the laboratory. Both batch and standard fabric samples were subjected to different tests for analyzing their quality parameters including color difference values, color fastness and color strength properties. The VFCW results demonstrated that the combination of VFCW with ozonation effectively reduced pollutants. The combined approach showed 92% removal efficiency in total suspended solids (TSS), 88% efficiency in BOD5 Removal, and showed 99% reduction in pathogen (E. coli) removal. The planted VFCW also showed significant reduction in TSS, BOD5 and E. coli with 80%, 67% and 97.3%, respectively. The textile wet processing results indicated that the quality of Batch 1 fabric samples, prepared using treated greywater in wash-off stages, is acceptable as compared to Batch 2 and Batch 3 samples which were prepared using treated greywater in dyeing stages of textile wet processing. This study concludes that domestic greywater has the potential to be used in textile wet processing and providing an alternative to freshwater consumption in textile industry. The current study highlights the potential of integrating multiple treatment methods for improving greywater quality and then reusing the combined treated greywater in textile wet processing. The study is aimed at increasing freshwater conservation and sustainable resource management in alignment with Sustainable Development Goal (SDG) 6 ‘Ensure availability and sustainable management of water’.

Greywater Reuse in Textile Industry after Treatment with Constructed Wetland Coupled with Ozonation

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发表日期：

2026年5月26日

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Farah Saeed,
Irfan Ahmad Shaikh

摘要

Water scarcity is an escalating global concern, particularly in urban areas where growing populations and increased domestic water use strains the limited freshwater resources. Greywater, which constitutes a significant portion (50- 80%) of household wastewater, offers valuable opportunity for reuse. This study determines the potential of greywater, treated with hybrid treatment system comprising of constructed wetland technology followed by ozonation, as an alternative to freshwater in textile dyeing process. Laboratory-scale vertical flow constructed wetland planted with Canna Indica followed by ozonation was employed for greywater treatment. The experimental setups were designed: planted, planted Vertical Flow Constructed Wetland (VFCW) with ozonation and unplanted VFCW serving as a control. Parameters including pH, electrical conductivity (EC) and temperature were measured using a multimeter. Total Suspended Solids (TSS) and Total Dissolved Solids (TDS) were measured using the gravimetric method. The 5-days Biological Oxygen Demand (BOD₅), phosphate and E. coli were analyzed by the standard methods of American Association of Public Health Administration (APHA) (2005). After both VFCW and Ozonation treatments, the combined treated greywater was used in textile wet processing as it aligned with the World Health Organization (WHO) Guidelines for the safe use of wastewater, excreta and greywater (2006). Batch fabric samples of selected reactive dyes were prepared by using treated domestic greywater in dyeing and washing stages of textile dyeing process while the standard fabric samples were dyed by using conventional tap water in the laboratory. Both batch and standard fabric samples were subjected to different tests for analyzing their quality parameters including color difference values, color fastness and color strength properties. The VFCW results demonstrated that the combination of VFCW with ozonation effectively reduced pollutants. The combined approach showed 92% removal efficiency in total suspended solids (TSS), 88% efficiency in BOD₅ Removal, and showed 99% reduction in pathogen (E. coli) removal. The planted VFCW also showed significant reduction in TSS, BOD₅ and E. coli with 80%, 67% and 97.3%, respectively. The textile wet processing results indicated that the quality of Batch 1 fabric samples, prepared using treated greywater in wash-off stages, is acceptable as compared to Batch 2 and Batch 3 samples which were prepared using treated greywater in dyeing stages of textile wet processing. This study concludes that domestic greywater has the potential to be used in textile wet processing and providing an alternative to freshwater consumption in textile industry. The current study highlights the potential of integrating multiple treatment methods for improving greywater quality and then reusing the combined treated greywater in textile wet processing. The study is aimed at increasing freshwater conservation and sustainable resource management in alignment with Sustainable Development Goal (SDG) 6 ‘Ensure availability and sustainable management of water’.