Metals in sugarcane molasses wastewater subjected to thermophilic anaerobic digestion

ABSTRACT

This study evaluated the occurrence and removal of eleven trace elements, B, Co, Cu, Fe, Mn, Mo, Ni, Se, V, W and Zn, from sugarcane molasses wastewater through a thermophilic anaerobic structured-bed reactor (AnSTBR). Concentration ranges in molasses were, in μg. L⁻¹: 19–277; 6–18; 37–449; 155–2160; 26–392; 3–15; 6–41; 12–46; 6–31; and 25–1648; for B, Co, Cu, Fe, Mn, Mo, Ni, Se, V, and Zn, respectively. Tungsten was not identified in the molasses. The average metal/nutrient removal efficiency was 62 ± 12, 58 ± 22, 55 ± 28, and 49 ± 12% for selenium, manganese, molybdenum, and iron, respectively. It is possible that the overall anaerobic digestion functioning is not affected up to these reported metal values. Environmental impacts from releasing effluent streams into soils and groundwater need to be investigated.

KEYWORDS:

• Metal removal
• anaerobic digestion
• sugarcane molasses

Acknowledgments

The authors are grateful for support from the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, Processes: 2015/06246-7 and 2016/24526-0), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Process: 303469/2017-0) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for this research work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo [2016/24526-0].