O uso do licor pirolenhoso como agente saneante em lodo de esgoto estabilizado

Abstract

Pyroligneous liquor is generated from condensation a part of wood carbonization gases. It consists of a chemical compounds range, such as acid and phenolic substances, and water, who have the highest volume concentration. Studies on the possible pyroligneous liquor uses are emerging in Brazil, mainly those related to antimicrobial properties. In this context, the present study aims to verify the efficiency of pyroligneous liquor as sanitizing for the disinfection of stabilized sewage sludge. The pyroligneous liquor samples was obtained experimentally from three carbonizations of Eucalyptus dunnii in circular masonry ovens. Small aliquots were taken directly from the collection tube at four-hour intervals to make the pH analysis. For the experimental treatment, samples were taken from the storage container at 88h from the start of carbonization process and also characterized according to pH. The stabilized sewage sludge samples were collected at the effluent treatment station in Ipiranga-PR, 12 days after discharge into drying beds, and characterized according International Technical Standard 23/2017 (Standard Methods for The Examination of Water and Wastewater) to determination of total, fixed and volatile solids. The experimental treatment consisted of applying pyroligneous liquor over the sludge samples using different dosages 0ml (control), 10ml, 30ml and 50ml. The treated samples were submitted to microbiological analysis according to the method proposed by Hoffman, Pons and Janer, performed after 24h, 48h and 50 days after the applications. The species identified in the control samples were Anciylstoma sp larvae and eggs, Ascaris lumbricoides larvae and eggs, Taenia sp eggs, Hymenolepis nana eggs and Giardia lamblia cysts. The sample treated analysis at 24h and 48h after pyroligneous liquor did not indicate the presence of parasites for all dosages greater than 0ml evaluated on this study. However, the analysis results after 50 days application showed the presence of parasites in sample treated with 10ml. Thus, the pyroligneous liquor has anthelmintic potential and could be a promising alternative for use as a sanitizing agent for stabilized sewage sludge. Its efficiency depends on the applied doses.