Blue and grey water footprint of textile industry in China

Water footprint (WF) is a newly developed idea that indicates impacts of freshwater appropriation and wastewater discharge. The textile industry is one of the oldest, longest and most complicated industrial chains in the world's manufacturing industries. However, the textile industry is also water intensive. In this paper, we applied a bottom-up approach to estimate the direct blue water footprint (WF_dir,blue) and direct grey water footprint (WF_dir,grey) of China's textile industry at sector level based on WF methodology. The results showed that WF_dir,blue of China's textile industry had an increasing trend from 2001 to 2010. The annual WF_dir,blue surpassed 0.92 Gm³/yr (giga cubic meter a year) since 2004 and rose to peak value of 1.09 Gm³/yr in 2007. The original and residuary WF_dir,grey (both were calculated based on the concentration of chemical oxygen demand (COD_Cr)) of China's textile industry had a similar variation trend with that of WF_dir,blue. Among the three sub-sectors of China's textile industry, the manufacture of textiles sector's annual WF_dir,blue and WF_dir,grey were much larger than those of the manufacture of textile wearing apparel, footware and caps sector and the manufacture of chemical fibers sector. The intensities of WF_dir,blue and WF^res_dir,grey of China's textile industry were year by year decreasing through the efforts of issuing restriction policies on freshwater use and wastewater generation and discharge, and popularization of water saving and wastewater treatment technologies.