Abstract
The municipalities have been making serious investments in sewer system infrastructures based on regulations in environmental policies in our country in recent years and the number of wastewater treatment facilities is increasing day by day. The increase in the refined wastewater amount also brings an increase in the amount of sewage sludge generated. In Turkey, the average amount of sewage sludge produced daily as dry substance is around 1000 tons. However, there are some problems with its elimination. Since sewage sludge contains organic substances at high amounts and also macro and micro elements necessary for plant nutrition, it has a potential to be utilized as soil reclamation material or organic fertilizer. Therefore, this study was planned based on the idea that innovative solutions were needed to strengthen the positive sides of sewage sludge for its safe recycling in the ecosystem. The main purpose of the research is to make the material safer for utilization by producing humic acid from sewage sludge and applying it to soil instead of applying sewage sludge directly to the soil. For this purpose, humic acid was obtained from stabilized and dried domestic sewage sludge by alkali / acid extraction. Humic acid produced was applied to the soil and a pot experiment was carried out by growing grass plants. Humic acid applications were made with 4 replicates at 0, 50,100, 150, 200 kg da-1 soil levels. Grass plants height, fresh weight, dry weight, SPAD chlorophyll meter readings, total chlorophyll analysis values increased compared to the control, but only SPAD values were found to be statistically significant.