| |
| Leather processing is associated with employment of many kinds of chemicals. These chemicals are usually used excessively in tanneries to ensure the quality of leathers. As a result, a part of the chemicals would inevitably remain in the tannery wastewater and form major pollutants of the leather industry. Biological treatment plays a significant role in removing these chemicals from wastewater and, in fact, biodegradability of these chemicals is directly related to their environmental friendliness. Recently, we have been undertaking a systematic evaluation of biodegradability of typical leather chemicals so as to characterize their environmental impact as exactly as possible. In this paper, the biodegradation behaviours of six typical fatliquor components, including sulfated castor, sulfated neat foot oil, sulfated fish oil, lecithin, chlorinated paraffin and alkyl sulfonyl chloride, were investigated. It has been found that four of them, sulfated castor, neat foot oil, fish oil and lecithin, can be effectively degraded by the activated sludge from the wastewater treating yard of tannery, which suggests that these four kinds of fatliquors are suitable to be used in leather making in consideration of their environmental friendliness. However, two other kinds of fatliquors, chlorinated paraffin and alkyl sulfonyl chloride, can not be degraded by activated sludge, and the presence of alkyl sulfonyl chloride in wastewater will lead to poisoning of activated sludge, which indicates that these two kinds of fatliquors should be limited in use. |
|
| Keywords:fatliquor,activated sludge,biodegradability |
|
