Effective sludge management: Reuse of biowaste and sewer sediments for fired bricks

ABSTRACT

This study partially replaced the clay with sewer sludge (SS) and rice husk (RH-SS) to make fired bricks. The brick samples were examed in terms of shrinkage, water absorption, and compressive strength. Besides, they were analyzed via XRD and metal extraction to determine the heavy metal residuals in the products. The results showed that it was possible to fabricate fired bricks using sewer sludge or rice husk-blended sludge with up to 30% by weight. These brick samples complied with the technical standard for clay brick production, in which the compressive strength was more than 7.5 MPa, water absorption was from 11–16%, and the linear shrinkage was all less than 5%. The rice husk addition helped mitigate the heavy metal residuals in the bricks and leaching liquid, in which all the values were lower than the US-EPA maximum concentration of contaminants for toxicity characteristics.

Implications: Previous studies have proved the possibility of mixing sewage sludge from different origins (sewage sludge, river sediment, canal sediment, sewer sediment, etc.) with clay and some wastes to make bricks. In which, mostof the studies used sewage sludge from wastewater treatment plants, very fewdealt with lake/river or sewer sediment. This study shall be the first to study the possibility of employing sewer sediments with the addition of rice husk powder to achieve two targets, including (1) the reuse of biowaste and sludge for brick fabrication and (2) the reduction of heavy metals in final calcined bricks. Different ratios of the rice-husk blended sewer sludge (RH-SS) – clay mixture shall be tested to find the optimized compositions. The results showed that it was possible to fabricate fired bricks using sewer sludge or rice husk-blended sludge with up to 30% by weight, which meant reduce 30% of clay in the brick production. The final products were proved to meet the quality standard in terms of compressive strength (more than 10 MPa), water absorption(from 11–16%), and the linear shrinkage (less than 5%). Larger scale of this study can be an evident to recommend for policy change in the waste reuse in construction field.

Acknowledgment

The authors would like to express high acknowledgment to the Ministry of Natural Resources and Environment, Vietnam, for sponsoring the project code TNMT.2023.05.05.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Supplemental data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/10962247.2024.2369294

Additional information

Funding

The work was supported by the Vietnam Ministry of Natural Resource and Environment [TNMT.2023.05.05].

Notes on contributors

Hoa Nhan Nguyen

Hoa Nhan Nguyen is a lecturer at Faculty of Materials Engineering, HUCE since 2005. He received a bachelor’s degree in Materials Engineering from HUCE in 2004 and a master’s degree in Materials Engineering from HUCE in 2008. He is interested in ceramic and glass materials; waste recycle and management.

Huyen T.T. Dang

Huyen T.T. Dang is an Associate Professor at Faculty of Environmental Engineering, Hanoi University of Civil Engineering (HUCE). She received a bachelor’s degree in Environmental Engineering from HUCE in 2002. She did her post graduate study at University of Ottawa (Canada) and obtained her Doctoral Degree in 2009. Her research fields of interest are membrane technology, water and waste reuse, sustainable drainage and green building.

Lan T.N. Pham

Lan T.N. Pham is an Associate Professor at Faculty of Chemistry and Environment, Thuy Loi University. She received a bachelor’s degree in Hydrology and Environment from Thuy Loi University in 1993. She did her post-graduate study and achieved the Degree of Master of Science in Soil and Water Engineering at Karlsruhe University in 1996. She did her PhD study at Thuy loi University and obtained her Doctoral Degree in 2012. She is interested in doing research in some areas including water quality management; water and wastewater treatment; solid waste recycle and sustainable drainage.

Huan Xuan Nguyen

Huan Xuan Nguyen is a doctor and researcher at Faculty of Environmental Sciences, University of Science (HUS), Vietnam National University (VNU) since 2006. He received a bachelor’s degree in Soil science from VNU in 2002 and a master’s degree in Environmental of Sciences in 2012. He gained his Doctoral degree from VNU in 2020. He is interested in analysis of elements and materials in the Chemistry lab for environment-related research projects.

Kien Ton Tong

Kien Ton Tong is a lecturer at the Faculty of Materials Engineering, Hanoi University of Civil Engineering (HUCE) since 2006 and a senior researcher of Research and Application for Tropical Building Materials Institute- Vietnam. He received a bachelor’s degree in Building materials and components from HUCE in 2005, a master’s degree in Building materials and technology in 2010, and a Doctoral degree in Materials Engineering from HUCE in 2017. He is interested in construction materials based on waste materials utilisation; Green and low carbon footprint material technologies for sustainable development.

Thuy T. Pham

Thuy T. Pham is an Associate Professor at Faculty of Environmental Sciences, University of Science, Vietnam National University (VNU). She received a bachelor’s degree in Environmental Engineering from Hanoi University of Civil Engineering in 2003. She did her post graduate study at Katholieke Universiteit Leuven (Belgium) and obtained her Doctoral Degree in 2012. Her research fields of interest are water and waste treatment, waste utilization toward circular economy.

Khai M. Nguyen

Khai M. Nguyen is a Professor at Faculty of Environmental Sciences, University of Science, Vietnam National University, Hanoi (VNU). He received a bachelor’s degree in Biology from VNU University of Science in 1996. He did his post graduate study at Swedish University of Agricultural Science and obtained his Doctoral Degree in 2007. He is director of VNU Key Laboratory of Green Environment, Technology and Waste Utilization, University of Science, Vietnam National University, Hanoi.

Hang T.M. Tran

Hang T.M. Tran is currently a lecturer in the Faculty of Environmental Sciences at the University of Science, Vietnam National University Hanoi. She has earned her Ph.D degree from The National University of Singapore. Her main research interests include marine pollution and conservation, water resources management, waste minimization and recycling, and sustainable development.