| چکیده انگلیسی مقاله |
The production of compost from biodegradable urban waste is one of the waste management methods. This research aimed to evaluate the quality of composts in the country. samples were collected from compost produced in factories in Mashhad, Kermanshah, Tehran (first and second grade from Kahrizak), Tabriz, and Isfahan (Isfahan, Shahin Shahr, Lenjan, and Najafabad) over a period of two years. The samples were analyzed for nitrogen, phosphorus, potassium, total lead, total nickel, total chromium, total cadmium, total arsenic, total cobalt, foreign materials, moisture, electrical conductivity, and acidity. none of the composts produced in the country met the standard conditions and failed to comply with the Iranian national standards in at least one or more parameters. The average concentrations of cadmium, lead, nickel, chromium, cobalt, and arsenic in the samples were 3.27, 134, 69, 76, 7.90, and 3 mg/kg of dry weight, indicating non-compliance rates of 6.5%, 16%, 11.2%, 9.47%, 0.59%, and 0%, respectively. The pH had an average of 7.32, showing a 13.4% non-compliance with standards. Electrical conductivity (EC), organic carbon (OC), carbon-to-nitrogen ratio (C:N), nitrogen (N), phosphorus (P2O5), potassium (K2O), and moisture content averaged 5.71, 20.7, 12.7, 1.81, 1.01, 0.96, and 23.6%, respectively, indicating non-compliance rates of 10.7%, 80.5%, 68%, 36.4%, 96.7%, 0%, and 31.4% compared to first-grade compost. it is necessary to evaluate and improve the quality of produced composts concerning organic carbon content and heavy metals, especially lead, to address the non-compliance issues in agricultural usage. |