بررسی تاثیر فرایند کمپوست سازی ضایعات فراوری پسته با تیمارهای مختلف بر غلظت فلزات سنگین

Abstract Introduction: Composting is one of the pistachio wastes management methods. In the appropriate compost production nutrients and heavy metals are determinant. The aim of this study is survey the effect of pistachio wastes composting process with different treatments on the concentration of heavy metals. Methods: In this study, during the 60-day pistachio wastes composting process with two treatments of dewatered sewage sludge and cow manure, pH, EC, carbon to nitrogen ratio, Heavy metals and nutrients indicators were studied. The results were compared with WHO and Iranian National standard. Drawing the diagrams by Excel software (Version 2007) and Statistical analysis was performed by Spss Software (version 20) at a significance level of 0.005.  Results: During the 60-day composting pH initially had downward trend and then increased. The Cu, Zn, Fe, Mn and C/N ratio had downward trend and the EC, Na, K had increasing trend. Eventually, Iron, zinc, copper and manganese were less than the standard, Sodium was in Standard range and potassium was more than specified standards in the produced compost from pistachios waste with both treatments.  Conclusion: The results showed that the concentration of heavy metals and nutrients in the produced compost with both treatments were in the acceptable range. Eventually quality of produced compost with cow manure treatment due to better decomposition and greater stability was better than processed compost with dewatered sewage sludge treatment.