Study Of Phytotoxic Properties Of Sewage Sludge Stabilised By Alkaline Mediums
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93 - 100
P. Samaras, C. A. Papadimitriou, E. Papastergiadis, A. Pappa & K. Gudulas
The aim of this work was the examination of the stabilization potential of sewage sludge by fly ash and lime and the investigation of the phytotoxic properties of the produced mixtures. About 0,5 m3 sewage sludge were mixed with the alkaline substances in various ratios and the products were stabilized for 3 months. Samples from each mixture were analyzed for the determination of their physicochemical content such as pH, moisture, and nutrients. Stabilization of sewage sludge was achieved depending upon the concentration and the type of alkaline medium, due to the pH increase of the mixture; however, the alkaline addition resulted in the reduction of the nutrients content. Phytotoxicity effects were determined by the measurement of the corresponding inhibition effects of the produced mixtures on the seed germination and root length growth of three higher plants (one monocotyl and two dicotyls). Samples obtained from the early stages of stabilization process exhibited high inhibition on seed germination and root length growth; however, these effects were reduced for samples prepared at extended stabilization times. Keywords: fly ash, lime, sewage sludge, stabilization, phytotoxicity. 1 Introduction The improvement of sewage sludge management is an important issue during the preparation of an integrated wastewater management plan. Sewage sludge has been already utilized in agricultural and horticultural applications for several years as it represents an alternative source of nutrients for plant growth, and an
fly ash, lime, sewage sludge, stabilization, phytotoxicity.