An artificial pond (about 2.6 hectares and 4 meters depth) was filled with the liquid and solid fine residual fraction from a biogas system located in an agricultural area (Central Italy). The resulting sludge consisted of about 80% of water; the fine fraction (20%) was characterized as: sand 15%, silt 60% and clay 25%, without any significant vertical stratification in the pond. The pH and the electrical conductivity were about 8 and 2.5 mS cm-1, respectively. The heavy metals detected at high concentrations were copper (1200 mg kg-1) and zinc (4000 mg kg-1). Zoocompost Project, funded by Umbria Region (Italy), aimed to test a green remediation technology for the treatment of this sludge by using phytoremediation and water phytoextraction. A phytoremediation pilot system was set up in a greenhouse for testing the effectiveness of different plant species and planting methods for sludge dehydration, as well as the quality improvement of the sludge. The tested plants (cuttings or rooted cuttings) were Tamarix gallica, Tamarix africana, Phragmites australis and a combination of Juncus effusus, Iris pseudacorus and Carex gracilis. The plant growth, the sediment water content, the main physico-chemical parameters and the pathogen occurrence in the sludge (E. coli and Enterobacteriaceae) have been analyzed in the greenhouse experiment. At the same time, the evolution of the microbial community after the plant addition has been evaluated by measuring its abundance, viability, activity (dehydrogenase activity) and diversity (Fluorescence In Situ Hybridization). The results of the first year of experiments are here reported.
Phytoremediation strategies for dehydration and quality improvement of a manure digestate sludge
Grenni P;Barra Caracciolo A;Massacci A;
2015
Abstract
An artificial pond (about 2.6 hectares and 4 meters depth) was filled with the liquid and solid fine residual fraction from a biogas system located in an agricultural area (Central Italy). The resulting sludge consisted of about 80% of water; the fine fraction (20%) was characterized as: sand 15%, silt 60% and clay 25%, without any significant vertical stratification in the pond. The pH and the electrical conductivity were about 8 and 2.5 mS cm-1, respectively. The heavy metals detected at high concentrations were copper (1200 mg kg-1) and zinc (4000 mg kg-1). Zoocompost Project, funded by Umbria Region (Italy), aimed to test a green remediation technology for the treatment of this sludge by using phytoremediation and water phytoextraction. A phytoremediation pilot system was set up in a greenhouse for testing the effectiveness of different plant species and planting methods for sludge dehydration, as well as the quality improvement of the sludge. The tested plants (cuttings or rooted cuttings) were Tamarix gallica, Tamarix africana, Phragmites australis and a combination of Juncus effusus, Iris pseudacorus and Carex gracilis. The plant growth, the sediment water content, the main physico-chemical parameters and the pathogen occurrence in the sludge (E. coli and Enterobacteriaceae) have been analyzed in the greenhouse experiment. At the same time, the evolution of the microbial community after the plant addition has been evaluated by measuring its abundance, viability, activity (dehydrogenase activity) and diversity (Fluorescence In Situ Hybridization). The results of the first year of experiments are here reported.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
