制革废水中氨氮的测定及来源分析(Ⅲ)

Determination of Ammonia Nitrogen in Tannery Wastewater and Analysis of its Origin (Ⅲ)

研究了制革准备工段各工序废水中有机氮的分布情况,分析了有机氮的来源及其与氨氮的关系。结果表明:与氨氮在脱灰、软化废水中含量最高的现象相反,有机氮在原皮水洗、浸水和浸灰工序中产生较多,这主要是由于皮中非胶原蛋白质的去除和水解。而整个准备工段胶原的损失仅贡献废水有机氮的2%左右。脱毛浸灰过程的有机氮污染最重,相对而言灰碱保毛脱毛法在降低有机氮负荷方面具有一定优势。总有机碳(TOC)含量与总有机氮含量呈正相关性,可作为监测制革废水有机物负荷的一项有效指标。

The contents of organic nitrogen and ammonia nitrogen in wastewaters from various beamhouse operations were determined. The origin of organic nitrogen and its relationship to ammonia nitrogen were explored. The results indicate that washing soaking and liming operations account for a majority of the organic nitrogen load in tannery wastewater, which is in contrast with the distribution of ammonia nitrogen that is mostly concentrated in deliming and bating processes. Organic nitrogen is mainly originated from the removal and hydrolysis of non - collagen proteins in the hide. This is supported by the fact that only two percent of organic nitrogen in beamhouse wastewaters comes from the degradation of collagen. The content of organic nitrogen in unhairing - liming operations is the highest, and hairing - saving process is shown to be the optimal method in terms of reduction of organic nitrogen. The total organic carbon content, which exhibits high correlation with the content of organic nitrogen, is an efficient parameter to be employed to evaluate the content of organic pollutant in the tannery wastewaters.