TY - JOUR
T1 - Recovery of humic acids from anaerobic sewage sludge
T2 - Extraction, characterization and encapsulation in alginate beads
AU - Cristina, Giulio
AU - Camelin, Enrico
AU - Ottone, Carminna
AU - Fraterrigo Garofalo, Silvia
AU - Jorquera, Lorena
AU - Castro, Mónica
AU - Fino, Debora
AU - Schiappacasse, María Cristina
AU - Tommasi, Tonia
N1 - Funding Information:
This work was conducted thank to the project “VALPO4CIRCULAR ECONOMY” funded by Compagnia San Paolo and Politecnico di Torino for the support of the internationalization of the research. The authors wish to thank Mr. Umberto Rossi for his constant attention to the issues related to soil degradation and restoration and for his support to the project. Finally, authors express gratitude to Camilo Carrasco and Soraya Salazar for their help during the laboratory work and analyses, and Miriam Montecinos for her support during the greenhouse trials.
Publisher Copyright:
© 2020
PY - 2020/12/1
Y1 - 2020/12/1
N2 - Wastewater production is rising all over the world and one of the most difficult problems is the disposal of sewage sludge (SS). It is known that SS contains certain quantities of added-value compounds, such as humic acids (HA) which in turn have beneficial effects on soil quality and plant growth. On the other hand, SS can retain many pollutants, such as heavy metals. The present work aimed to implement an HA alkaline extraction protocol from anaerobic sewage sludge (ASS). Subsequently, the HA were quantified in ASS, in HA extract and in commercial HA, used as a benchmark, which gave results of 12.53%, 26.87% and 77.87% (on dry matter basis), respectively. FESEM and EDX analyses on lyophilized HA extract confirmed that no heavy metals had passed into the extract. Afterwards, in order to allow controlled release of the HA in soils, alginate beads containing the HA extract were created. Finally, a pot experiment in a greenhouse was performed using Chilean lettuce plants (Lactuca sativa L.) treated with alginate-HA extract beads. At the end of the greenhouse experiments, the hypogean dry biomass of the treated plants was significantly higher than for non-treated plants. The relevance of this study relies not only on the exploitation of green chemistry principles, by converting a waste stream into a high-value product, but also on the application of an approach following a circular economy model.
AB - Wastewater production is rising all over the world and one of the most difficult problems is the disposal of sewage sludge (SS). It is known that SS contains certain quantities of added-value compounds, such as humic acids (HA) which in turn have beneficial effects on soil quality and plant growth. On the other hand, SS can retain many pollutants, such as heavy metals. The present work aimed to implement an HA alkaline extraction protocol from anaerobic sewage sludge (ASS). Subsequently, the HA were quantified in ASS, in HA extract and in commercial HA, used as a benchmark, which gave results of 12.53%, 26.87% and 77.87% (on dry matter basis), respectively. FESEM and EDX analyses on lyophilized HA extract confirmed that no heavy metals had passed into the extract. Afterwards, in order to allow controlled release of the HA in soils, alginate beads containing the HA extract were created. Finally, a pot experiment in a greenhouse was performed using Chilean lettuce plants (Lactuca sativa L.) treated with alginate-HA extract beads. At the end of the greenhouse experiments, the hypogean dry biomass of the treated plants was significantly higher than for non-treated plants. The relevance of this study relies not only on the exploitation of green chemistry principles, by converting a waste stream into a high-value product, but also on the application of an approach following a circular economy model.
KW - Circular economy
KW - Greenhouse experiment
KW - Humic acids extraction
UR - http://www.scopus.com/inward/record.url?scp=85088284208&partnerID=8YFLogxK
U2 - 10.1016/j.ijbiomac.2020.07.097
DO - 10.1016/j.ijbiomac.2020.07.097
M3 - Article
C2 - 32673726
AN - SCOPUS:85088284208
VL - 164
SP - 277
EP - 285
JO - International Journal of Biological Macromolecules
JF - International Journal of Biological Macromolecules
SN - 0141-8130
ER -