Thickening and Storage of Sewage Sludge Contribute to the Degradation of LAS and EOX and the Humification of Organic Matter

Land application of sewage sludge on agricultural soils can be sustainable only if pollutant contents and organic matter quality meet the requirements imposed by minimization environmental risks. This study investigated degradation linear alkylbenzene sulfonates (LAS) extractable halogens (EOX) formation humic substances (HS) during thickening storage phases treatment. Changes in spectroscopic properties (UV-Vis, FT-IR, excitation-emission matrix (EEM) fluorescence) HS were also evaluated to assess occurrence biological activities these curing (SS). Humic acids (HA), fulvic (FA), EOX, LAS extracted from sampled four municipal wastewater treatment plants different size sequence, before after 90 days aerobic or anaerobic storage. During storage, loss C SS ranged almost null 31%. No significant changes FA registered, whereas HA increased all samples, up 30%. The amount synthesized correlated with percentage lost. Spectroscopic showed an increase their aromaticity, a corresponding decrease aliphatic contribution. These show improved agronomical SS. decreased 30%, surprisingly more under than conditions, EOX significantly even 81%. In conclusion, although may normally considered not influencing SS, contamination whatever conditions oxygen availability applied.