An investigation of agricultural use potential of wastewater sludges in turkey with respect to heavy metals and pathogens


Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Çevre Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2006

Tezin Dili: İngilizce

Öğrenci: GÜLÇİN ÖZSOY

Asıl Danışman (Eş Danışmanlı Tezler İçin): Faika Dilek Sanin

Eş Danışman: Filiz Bengü Dilek

Özet:

Landfilling is the most common method that is used in the final disposal of sludge all around the world as well as in Turkey. However increasing sludge quantities and limited landfilling areas make this method invalid. Use of sludge in agriculture presents a possible alternative for disposal. However, it also poses some risks to be evaluated. In this respect, it is important to identify heavy metal and pathogen content of sewage sludges because of their adverse health effects. This study aims to determine the heavy metal contents and pathogen levels of sludges from four different wastewater treatment plants of Turkey. The selection of plants was done according to the different treatment technologies applied to wastewater and sludge in those plants. Heavy metal analysis of sludges was conducted by using microwave assisted digestion procedure and pathogen levels were done by methods from Standard Methods (SM), ISO and USA EPA. After sampling and analysis, the results show that all the related metal concentrations are below the values that are set in the Soil Pollution Control Regulation of Turkey. However in sludges from Ankara and Kayseri wastewater treatment plants, Zinc and Nickel concentrations should be tracked carefully. The results related with pathogen levels in sludges show that dewatered sewage samples taken from Ankara, Kayseri and Kemer wastewater treatment plants do not meet neither Class A nor Class B fecal coliform limits set by USA EPA however lime stabilized dewatered sludge from İzmir wastewater treatment plant meet the requirement. In addition, Salmonella levels in Kayseri dewatered sludges exceed the limit value.