Experimental Study on Nitrogen Existing Forms of Sewage Sludge by Using Spectrophotometry and XPS Method

Abstract

Thermal disposal of sewage sludge for energy utilization is a feasible treatment with potential energy benefit, while the high content of N causes serious nitrogen related problems. In this study, the forms and contents of nitrogen were determined by using spectrophotometry and XPS method. According to the result, the organic-N was the dominated component which occupied 99.35% of total nitrogen. The content of nitrogen of sludge was 4.43% by using XPS, which was slightly higher than the measured value of elemental analysis, which was 3.80%. The most essential part of organic-N was protein-N, which processed 88.01% and 66.55% by using spectrophotometry and XPS nitrogen peak curve fitting methods respectively. XPS can only detect the content of nitrogen in sludge sample surface and the curve fitting method application was limited, which can’t reflect the real composition of nitrogen of sludge sample.