Sustainable processess

摘要

During the tanning process, large volumes of water and chemicals are used. Some of these chemicals can be harmful to the environment and people's health should they be misused; therefore, water pollution must be controlled. The most significant loads in each stage are shown in Table 1 (BAT, 2013). Unhairing is the most polluting stage of the tanning process, as shown in Table 1. Sulfide will be determined by the percentage of Na_2S used. Hide and solubilised hair proteins are responsible for COD, BOD, SS and TKN. Strong reducing agents, such as Na_2S, are used in this stage to destroy keratin. In acidic conditions Na_2S can react to produce H2S, which is a an extremely irritating and toxic gas that may cause death at very low concentrations.