Heavy Metals Removal from Sewage Sludge and Municipal Solid Waste (MSW) by Co-Composting Process

Background Aims of the Study: One of the most important pollutants in drinking water, air and soils is heavy metals. It is very harmful for humans and other live organisms. The purpose of this study was the usage of a co-composting process for removal of heavy metals from municipal solid waste and sewage sludge. Materials and Methods: This experimental study was a conducted sewage sludge and municipal solid waste. For collection of samples from urban solid waste composting and wastewater treatment plant, a 200 mL polyethylene bottles was used, samples after acidification were stored in a dark place at 4°C temperature until the metals analysis the heavy metals values remaining in the samples was measured by graphite furnace absorption spectrometer method (Varian, SpectrAA 240, Australia). In this study, we used SPSS version 16 for data processing; and they were also analyzed by descriptive statistics. Results: Result of this study showed that values of C/N in the first, second and third stage compost were 31.7, 27.3 and 41.8, respectively. Based on the result of this study the value of removal of Cd with 9.8 mg kg^-1 in first stage and Cr, Cu and Zn with 89, 21 and 87.6 mg kg^-1 in third stage were highest treatment. Conclusion: Our results show that co-composting process between many treatment processes having to be cost effective for heavy metal removal from solid waste and wastewater treatment.