Panagiotis Tziachris
Spatial Information Manager
Soil Science Institute of Thessaloniki
Greece

Biography
Panagiotis Tziachris holds an MSc and Ph.D. in spatial data and he is working for the last 13 years in the Hellenic Agricultural Organization-Institute of Soil and Water Resources in Thessaloniki, Greece. His main responsibilities are the integration of spatial data and new technologies in different scientific contexts, and mainly in the agricultural sector. He is also interested in Spatial Data Infrastructures (SDI), spatial data and their integration in human processes, and the future and evolution of spatial information in general.

Abstract
Usage of Sewage Sludge in the Agriculture Based on Spatial Data and European Directives in the City of Thessaloniki, Greece

Co-Authors:
Frantzis Papadopoulos, MSc, PhD, Soil Science Institute of Thessaloniki
Eirini Metaxa, MSc, Soil Science Institute of Thessaloniki

The EU environment policy as expressed through the 7th Environment Action Programme (EAP), focus its efforts to protect the natural capital, to stimulate resource-efficient, low-carbon growth and innovation, and to safeguard people's health and wellbeing while respecting the Earth's natural limits. In the 7th EAP there is also special interest on turning waste into a resource, with more prevention, re-use and recycling and to help cities become more sustainable. Based on these proposals, in the current paper, the usage of the sewage sludge from the Waste Water Treatment Plant (WWTP) of Thessaloniki (Greece) in the agricultural sector, is presented. The WWTP of Thessaloniki city serves about 1 million residents by treating daily 170.000-180.000 m3/d of raw wastewater, leaving tons of sewage sludge that are stored, on site. Up to 2010 there was no provision for the reuse of the stored sludge. In the following years, sludge reuse started and was continued with an increasing rate, providing an alternative soil-enhancement product for crops, based on European directives. With the collaboration of the public sector, private sector and research institute, through a bottom-up effort, this reuse was enhanced with the integration of spatial data and specialized algorithms that guides the user to the rational application of the sewage sludge to the farms, according to their soil parameters and their crops' needs.