Reclamation with phytoremediation of area affected by sewage sludge at the Thessaloniki Wastewater Treatment Plant in Sindos (Greece)

Abstract

The present research focused on the experimental investigation of phytoreclamation of areas affected by sewage sludge disposal and improving the quality of the sludge. It was conducted in two stages: laboratory and pilot applications. This paper reports on the first stage, which tested, under greenhouse conditions, the possibility of using various species of plants cultivated in the sludge from the Thessaloniki Wastewater Treatment Plant (ThWWTP, Greece) with different amendments. The results of the 30-day experiment showed that the quality of the output sludge material varied significantly in comparison to the input sludge material. These variations were considered as positive, as the output sludge obtained texture and structure, aeration conditions were improved, and the content of some trace metals, excess nutrients (e.g., P), and salts (of Na) were reduced. These were all influenced by both the type of treatment and the plant species used. In conclusion, the best treatments, T1, T3, and T4 (soil/sludge mixture 70%/30%, soil/sludge/gravel mixture 50%/25%/25%, and soil/sludge/gravel mixture 45%/45%/10%, respectively), and the best suited plant species, Helianthus annuus L. and Zea mays L., were proposed to be used in the pilot application (in situ) at the site within the ThWWTP.

Keywords:

• sewage sludge
• phytoremediation
• reclamation
• trace elements

Acknowledgments

This research was conducted in the framework of the cooperation between the Thessaloniki Water Supply and Sewerage Co., SA (EYATh) and the Aristotle University of Thessaloniki (AUTh) with financial and technical support from both organizations. Some authors also received grants from the European Union through the ERASMUS MUNDUS External Cooperation Window Programme (Lot 6 – Belarus, Moldova, and Ukraine). A scholarship was also awarded by the Greek Republic Ministry of Education Lifelong Learning and Religious Affairs through the State Scholarship Foundation (I.K.Y.) for the purpose of this study. The technical support and help of A. Soupilas, K. Zambetoglou, G. Argiropoulos, and K. Kotoulas from the EYATH, and K. Noula and work force from “Actor,” are greatly acknowledged. Special thanks to Katie Quartano for revisions made in the use of English.