Utilization of dehydrated sewage sludge as an alternative nutrient to stimulate lipid waste degradation by the thermophilic oxic process.
Dehydrated and dried powdered sewage sludge (SW) was examined for use as an alternative to yeast extract (YE) to promote the degradation of lipid materials by a thermophilic oxic process (TOP). Its stimulatory effect on lipid degradation was found to be superior to that of YE. When 1.5 g of SW was added in combination with urea and 60 ml of a trace-element solution, the degradation efficiency was 82.9% for a 120-h treatment of 15 g of salad oil while that attained with YE was 68.3%. Although the degradation efficiency attained for animal fat, lard, was 77.8% which was lower than for vegetable oil, salad oil, it was still comparable to that obtained with YE, 76.9%. The applicability of SW to lipid degradation was confirmed in tests on three kinds of highly concentrated lipid wastes. With a nutrient supplement consisting of SW, a constant degradation efficiency of around 75% in 120-h treatment was attained for all lipid wastes despite their different features. The results of an elemental analysis suggested that the effectiveness of SW as a nutrient to stimulate thermophilic microbial activity in TOP was attributable to both a sufficient quantity and variety of amino acids and mineral components.
Nakano
Kazunori
K
Institute of Applied Biochemistry, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
Matsumura
Masatoshi
M