Fertilizing Potential Assessment of Livestock Industrial Abattoir Refinery Sludge and Its Effect on Soil Chemical Properties (Case Study: Livestock Industrial Abattoir of Sanandaj)

Application of sewage sludge in low organic matter agricultural soils is one of the most important methods for healthy recycling of such organic waste. But the presence of contaminants such as heavy metals in sewage sludge may pose risks and hazards to humans and the environment, which must be evaluated before use. This study was conducted to investigate the effect of industrial abattoir refinery sludge, produced in Sanandaj city, on improving the soil quality and health. Furthermore, the effect of sludge on the soil chemical properties was investigated by treating the soil with 12 ton ha-1 of sludge and incubating it for 70 days. The results of comparing sludge properties with valid standards showed that this sludge is in the standard range of organic fertilizers for agricultural purposes in terms of pH, total C, N, K, Na, Mn, Fe, Zn, Pb, Ni and Cd. But the salinity of the sludge with a Hazard Quotient (HQ) of 1.5 was slightly above the standard level of organic fertilizers for agricultural purposes. Furthermore, soil treated with the sludge increased N (148.4%), NO3 (113.7%), C (20%), P (118.2%), Fe (90.7%), Zn (440%) and Na (66%) as compared to the control soil. Based on the results of this assessment, in general the quality of the sludge is suitable for agricultural purposes. However, it is suggested that the sludge is examined in terms of microbial and organic contamination before it is used in agriculture.