Evaluation of Maturity Parameters and Heavy Metal Contents in Composts from Incense Bamboo Waste

Abstract

This research focused on improving the composting process of incense bamboo waste by analyzing compost maturity indicators and heavy metal concentrations. A large-scale experiment was set up using incense bamboo waste combined with different organic and biological amendments, including cow dung, poultry manure, and lignolytic fungi. The compost piles were manually turned every 15 days, and weekly samples were collected for monitoring. Among all treatments, the mixture containing 5 kg of cow dung, 2.5 kg of poultry manure, and 0.2 kg of lignolytic fungi resulted in the most effective breakdown of organic material. This treatment showed significant reductions in organic carbon, the carbon-to-nitrogen ratio, lignin, cellulose, and hemicellulose content, along with the lowest recorded levels of heavy metals such as iron, zinc, manganese, and copper. Additionally, the final compost from this treatment exhibited ideal characteristics in terms of pH, electrical conductivity, ash content, bulk density, and color. A notable improvement in seed germination and germination index (GI), with values exceeding 90%, indicated high compost maturity. While the results strongly support the effectiveness of using organic and biological additives, minor human errors—such as inconsistencies in turning, sampling, and measurement—may have affected some data points. Overall, the study confirms that using targeted additive combinations can enhance compost quality and maturity, and that selected parameters can reliably assess the readiness and safety of incense bamboo compost.