Performance assessment and economic aspects for water reclamation from UASB reactor effluent: Influence of coagulant type and membrane pore size

ABSTRACT

This paper investigates the influence of coagulant type in coagulation, flocculation and sedimentation processes and membrane pore size on the performance and economic aspects of water reclamation from UASB reactor effluent. The methodology involved laboratory-scale experiments using two different coagulant types (a modified tannin coagulant, TANm, and a polyaluminum chloride, PACl) and membrane filtration tests with microfiltration (MF) and ultrafiltration (UF). Compared to PACl, TANm had a smaller effect on the pH, consumed less alkalinity, and generated less sludge. However, PACl was more efficient in removing turbidity (89–97%), organic matter (70–72%), and phosphorus within the dosage range of 25 to 100 mg.L⁻¹. Both membranes achieved high removal rates for turbidity and organic matter. Despite the higher flux decay, the MF system could have higher operating flux and lower fouling resistance. The operating costs were higher for the C/F systems, which was attributed to the cost of coagulants and sludge disposal. The system with MF membranes had a lower total cost, and the estimated payback period for the investment was between 0.73 to 0.24 years, based on the values charged for reuse water. This information can be used to optimize the design and operation of UASB-based water reclamation systems.

KEYWORDS:

• UASB effluent
• coagulants
• tannin
• PACI
• membrane filtration

Acknowledgments

The authors wish to thank the Multiuser Experimental Central of UFABC (CEM-UFABC) for all laboratories, equipment and reagents made available for the accomplishment of this research. The authors wish to thank the São Paulo Research Foundation (FAPESP) (Grant number: 2016/23684-0 and 2020/11059-0) and CNPq (Grant number: 409693/2021-9).

Disclosure statement

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

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article and its supplementary materials.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/01496395.2024.2351096

Additional information

Funding

The work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico [409693/2021-9]; Fundação de Amparo à Pesquisa do Estado de São Paulo [2016/23684-0].