질소 성분의 경우 슬러지와 석탄 시료가 각각 4.43%와 1.89%를 차지했으며, 슬러지 시료는 석탄보다 2배 이상 많았다.
For nitrogen components, sludge and coal samples took up 4.43% and 1.89%, respectively, and the sludge sample had more than twice as much as those of coal.