Fertilizer production from leather waste

In this thesis, two crucial issues have been addressed: solid waste management in the leather industry and soil fertility in agriculture. Organic leather wastes, which contain dangerous amounts of chromium and cause significant storage problems, are primarily removed by the acid hydrolysis process, and collagen with high nitrogen content is obtained. The result was determined that the surface shape of the obtained collagen changed in the SEM image. In the EDS analysis, and there was approximately 16,8% nitrogen (N), 38,5% carbon (C), 8,9% phosphorus (P) in the structure of collagen, while chromium was completely removed from the structure. In the EDS analysis of biochar (char) obtained from cucumber peel pyrolysis, the presence of 3,8% P and 13,1% K were observed. The obtained material with high nitrogen content, collagen, was mixed with char, which is the pyrolysis product of cucumber peel, which has high potassium and phosphorus content, in a ratio of 1:1. The characterization of the prepared organic fertilizer was carried out with SEM and EDS analyze. The EDS analysis determined the NPK rate as 7,0%, 4,4%, and 6,3%, respectively. To evaluate the effectiveness of the prepared mixture as a fertilizer, the effect on the development of the pepper plant (Capsicum Annum) was examined. By mixing different proportions of organic fertilizer into the soil of the pepper plant, parameters such as plant height and diameter, and the number and size of leaves were monitored. The result determined that plant height increased 1,6 times, the number of leaves 1,8 times, leaf size 3,3 times, and total chlorophyll content 1,2 times compared to untreated soil (control), and these results were similar to the results in soil with chemical fertilizers.