A multi-criteria decision analysis of management alternatives for anaerobically digested kraft pulp mill sludge

• Published in: PloS one Vol. 13; no. 1; p. e0188732
• Main Authors: Eikelboom, Martijn, Lopes, Alice do Carmo Precci, Silva, Claudio Mudadu, Rodrigues, Fábio de Ávila, Zanuncio, Antônio José Vinha, Zanuncio, José Cola
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 03.01.2018; Public Library of Science (PLoS)
• Subjects: Air pollution; Algae; Alternatives; Anaerobic digestion; Analysis; Biodiesel fuels; Biofuels; Biogas; Biology and Life Sciences; Biomass; Carbon dioxide; Carbon dioxide emissions; Cellulose; Combustion; Composting; Decision analysis; Decision making; Earth Sciences; Ecology and Environmental Sciences; Economic conditions; Emissions; Energy costs; Energy recovery; Engineering and Technology; Environmental impact; Environmental risk; Feasibility; Fuels; Gasification; Groundwater; Health risks; Heavy metal content; Incineration; Kraft pulp; Land application; Landfill; Landfills; Materials recovery; Medicine and Health Sciences; Mills; Multiple criterion; Nitrogen; Pathogens; Physical Sciences; Pollution; Public health; Pulp; Pulp & paper mills; Pulp mills; Pyrolysis; Recycling; Sludge; Sludge digestion; Sludge disposal; Sustainable waste management; Waste disposal; Waste disposal sites; Waste management; Wood pulp industry; Brazil; United States > US; China
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0188732

The Multi-Criteria Decision Analysis (MCDA) procedure was used to compare waste management options for kraft pulp mill sludge following its anaerobic digestion. Anaerobic digestion of sludge is advantageous because it produces biogas that may be used to generate electricity, heat and biofuels. However, adequate management of the digested sludge is essential. Landfill disposal is a non-sustainable waste management alternative. Kraft pulp mill digested sludge applied to land may pose risks to the environment and public health if the sludge has not been properly treated. This study is aimed to compare several recycling alternatives for anaerobically digested sludge from kraft pulp mills: land application, landfill disposal, composting, incineration, pyrolysis/gasification, and biofuel production by algae. The MCDA procedure considered nine criteria into three domains to compare digested sludge recycling alternatives in a kraft pulp mill: environmental (CO2 emission, exposure to pathogens, risk of pollution, material and energy recovery), economic (overall costs, value of products) and technical (maintenance and operation, feasibility of implementation). The most suitable management options for digested sludge from kraft pulp mills were found to be composting and incineration (when the latter was coupled with recycling ash to the cement industry). Landfill disposal was the worst option, presenting low performance in feasibility of implementation, risk of pollution, material and energy recovery.