abstract
This study aims to explore an innovative approach consisting of the Fenton's process to stabilise organic wastes as an alternative to the traditional aerobic decomposition (composting). Digestate from the anaerobic digestion of the organic fraction of municipal solid wastes was taken from a mechanical-biological treatment plant and was thoroughly characterised regarding physical, chemical and biological properties. This sludge contained around 7.8 g Fe kg TS-1, which can be beneficial to the chemical oxidation. However, the use of zero-valent iron nanoparticles or iron(II) salt revealed treatment can be improved by adding extra iron into the system. The response surface methodology determined that the best peroxidation conditions were 35.6 g H2O2 kg TS-1 and 33.1 g Fe2+ kg TS-1, while maintaining constant pH 3, L/S 5 and room temperature. The chemical treatment enhanced the stability, reducing the oxygen uptake rate from 4.63 to 2.57 g O-2 kg VS-1 h(-1). Moreover, the germination index increased from 37 to 99.9 %, which means the treatment yielded a non-phytotoxic product. The outcomes of the present study are promising and open a new pathway for the Fenton peroxidation in semi-solid processes since this fast method can be very competitive when compared with the slow composting technology.
keywords
SEMISOLID FENTON PROCESS; ANAEROBIC-DIGESTION; IRON NANOPARTICLES; CONTAMINATED SOIL; SEWAGE-SLUDGE; COMPOST; DETOXICATION; SPECTROSCOPY; STABILITY; OXIDATION
subject category
Environmental Sciences & Ecology
authors
Quina, MJ; Lopes, DV; Cruz, LG; Andrade, J; Martins, RC; Gando-Ferreira, LM; Dias-Ferreira, C; Quinta-Ferreira, RM
our authors
Célia Maria Dias Ferreira
Post-Doc Fellowship
Daniela Vanessa Rosendo Lopes
Junior Researcheracknowledgements
This work is funded by the European Regional Development Fund (ERDF) through COMPETE-Operational Programme for Competitiveness Factors (OPCF), and by Portuguese National funds through the FCT-Fundacao para a Ciencia e a Tecnologia, under the Project PTDC/AGR AAM/101643/2008 NanoDC. R.C. Martins gratefully acknowledges the FCT for the financial support under the Post-Doc Grant (SFRH/BPD/72200/2010). C. Dias-Ferreira gratefully acknowledges the FCT-Fundacao para a Ciencia e a Tecnologia for financial support (SFRH/BPD/100717/2014). The authors acknowledge the valuable analytical contribution of Prof. Luis Miguel Castro.