ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Leaching of Organic and Inorganic Micropollutants from Chemically Stabilized Sewage Sludge-OFMSW Mixtures

M. Janosz-Rajczyk and E. Wiśniowska

Department of Chemistry, Water and Wastewater Technology, Czestochowa University of Technology, PL-42 200 Czestochowa, Poland

E-mail: ewisniowska@is.pcz.czest.pl

Abstract: Chemical oxidation of organic matrices is a promising alternative to biochemical and physical methods of waste treatment. In our study peroxyacetic acid and Fenton’s reagent were used to oxidize mixture of sewage sludge and organic fraction of municipal solid waste (OFMSW). Before chemical stabilization the mixture was digested for 3 d at 37^oC. Chemical stabilization with CH₃COOOH, H₂O₂, and FeSO₄ · 7H₂O was performed in 1 dm³ glass reactors for 24 to 72 h. Environmental effect of stabilized mixtures was evaluated using elution test according to the procedure given in PN-Z-15009/1997. In eluates selected organic (16 polycyclic aromatic hydrocarbons – PAHs) and inorganic (heavy metals) micropollutants were analyzed. The most abundant congeners in supernatant were naphthalene (average concentration 2.84 μg dm⁻³), chrysene (2.39 μg dm⁻³), and benzo(b+k)fluoranthene (4.54 μg dm⁻³). The less abundant ones were acenaphthylene and acenaphthene. In water extracts the most abundant hydrocarbons were also naphthalene and selected 5- and 6-ring compounds. There was no correlation between individual PAH concentration and log Kow value. Individual PAHs concentration in eluted solution was lower than the corresponding solubilities of PAHs in water. Total concentration of heavy metals (Hg, Cu, Fe, Pb, Cd, Zn, Ni, Mn, Cr) reached 1900 μg dm⁻³. The most abundant pollutants were Fe, Zn, and Mn. The lowest concentration was observed for Hg. Heavy metals concentration in the eluted solution was lower than level usually observed in landfill leachates. The results of the tests indicate that peroxyacetic acid and Fenton’s reagent chemical stabilization by-products should not be disposed on the landfills without further utilization; chemical stabilization is, however, the right way of the organic matter stabilization.

Full paper in Portable Document Format: 596ba453.pdf

Chemical Papers 59 (6b) 453–457 (2005)