Nitrogen removal based on anammox-based processes applied to mature landfill leachate diluted with domestic wastewater: a review

ABSTRACT

The anammox process is considered a sustainable, low-cost, and promising alternative for the treatment of effluents with high concentrations of nitrogen (N) and low concentrations of chemical oxygen demand (COD). Mature landfill leachates are rich in nitrogen and a potential source of water and soil contamination, potentially causing eutrophication of surface water bodies. In developing countries, leachates have been treated together with municipal effluents in WWTP. However, there are few reports on nitrogen removal in these systems. This review evaluated studies using anammox-based processes, including partial nitrification and anammox (PN/A), focusing on mature leachates and their co-treatment with municipal wastewater. We aimed to identify anammox-based treatment strategies leading to high N and COD removal efficiencies. For PN/A, sequential batch reactors have been successfully used to treat different effluents such as leachates. Recirculation and leachate dilution in anammox-based processes were strategies successfully adopted to achieve high nitrogen removal. Temperatures above 30°C and pH values from 7.8–8.5 had positive effects on the performance of co-treatment processes. The best performances in the co-treatment processes using PN/A were achieved for dilution rates between 2 and 11.5 parts of municipal wastewater to 1 part of mature leachate, reaching N and COD removal efficiencies above 90% and 86%, respectively. Inhibition of nitrite-oxidizing bacteria, acclimatization of anammox bacteria for long periods, as well as extracellular polymeric substances production by anammox bacteria are important factors in the performance of PN/A systems for the co-treatment of mature leachate and domestic wastewater.

GRAPHICAL ABSTRACT

KEYWORDS:

• Anammox
• Nitrogen removal
• Landfill leachate
• Partial nitrification
• Co-treatment

Acknowledgements

This work was supported by the Brazilian National Council for Scientific and Technological Development (CNPq), the Coordination for the Improvement of Higher Education Personnel (CAPES), and the Minas Gerais State Agency for Research and Development (FAPEMIG). L.F.A. was supported by CAPES. C.L.M. and J.C.A. were supported by the Brazilian National Council for Scientific and Technological Development (CNPq) under Grants 152488/2019-7 and 306198/2019-3, respectively.

Disclosure statement

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

Additional information

Funding

This work was supported by CAPES: [Grant Number ]; CNPQ: [Grant Number 152488/2019-7,306198/2019-3]; Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais? Pesquisa do Estado de Minas Gerais: [Grant Number ].

Notes on contributors

Luyara de Almeida Fernandes

Luyara de Almeida Fernandes is a doctoral student in sanitation, environment and water resources (SMARH) at the Department of Sanitary and Environmental Engineering at the Federal University of Minas Gerais (UFMG) – Brazil. She holds a bachelor's degree in environmental and sanitary engineering from the University Center of the East of Minas Gerais (Unileste) (2013) and a master's degree in SMARH (2017) from UFMG. Her research is directed towards the biological removal of nitrogen from effluents using processes based on anammox. She is currently investigating the co-treatment of mature leachate and domestic anaerobic effluent under tropical climate conditions. She is interested in strategies and operational conditions to increase the efficiency of anammox reactors, as well as in processes scale-up for technology dissemination.

Camila Leite Madeira

Camila Leite Madeira is a postdoctoral researcher at the Department of Sanitary and Environmental Engineering at Federal University of Minas Gerais – Brazil. She received her bachelor’s degree in environmental engineering from the Federal University of Itajubá – Brazil, and her master’s and PhD degrees in environmental engineering from the University of Arizona – USA. Her research focuses on bioremediation, toxicity and fate of emerging contaminants. Currently, she has been working on biological processes for wastewater treatment. She is also interested in promoting inclusive education for underrepresented students in STEM programs.

Juliana Calábria de Araújo

Juliana Calabria is an Associate Professor at the Department of Sanitary and Environmental Engineering at Federal University of Minas Gerais – Brazil. She was trained as a biologist and did a PhD in Sanitation Engineering at the University of São Paulo (USP), with an internship period at EAWAG (Switzerland) at the Microbiology and Molecular Biology Department. In 2018 she held a post-doctoral position at the University of Toronto (Canada). She has extensive experience in biological treatment of effluents and organic wastes, with emphasis in microbiology of anaerobic processes and molecular microbiology and ecology. She has joined the Sanitary and Environmental Engineering department at UFMG in 2006 and started to work with post-treatment of anaerobic effluents using Anammox (anaerobic ammonium oxidation) process. Since 2010, she has been working on several projects investigating microbial communities in different biological reactors (used in the treatment and post-treatment of municipal wastewaters) and in anaerobic digesters. She is deputy coordinator of the National Institute of Science and Technology on Sustainable Sewage Treatment Plants. She was the coordinator of the Graduate Program of Sanitation, Environment and Water Resources at UFMG from 2012 to 2015.