Valorisation of ferric sewage sludge ashes: Potential as a phosphorus source.
Waste Manag
; 52: 193-201, 2016 Jun.
Article
em En
| MEDLINE
| ID: mdl-27033993
ABSTRACT
Sewage sludge ashes (SSA), although a waste, contain elements with socio-economic and environmental potential that can be recovered. This is the case of phosphorus (P). SSA from two Danish incinerators were collected during two years and characterized. The sampling was done immediately after incineration (fresh SSA) or from an outdoor deposit (deposited SSA). Although morphology and mineral composition were similar, physico-chemical and metal concentration differences were found between incinerator plants and sampling periods. No differences were observed between deposited and fresh SSA, except for the parameters directly influenced by disposal conditions (e.g. moisture content). All the SSAs had high concentrations of P (up to 16wt%), but they all exceeded Danish EPA Cd and Ni thresholds for direct application at agricultural soil. Fresh and deposited SSA were acid washed aiming P extraction, achieving 50gP/kg (approx. 37% of total P), but metals were also co-extracted to the liquid phase. To avoid and/or minimize the metals pollution of the extracted P, selective P recovery from the SSA was tested, using the electrodialytic (ED) process. ED laboratory cells, with 3 compartments (3c) and 2 compartments (2c), and two acid concentrations (H2SO4, 0.08M and 0.19M) were used for 7days. The most concentrated acid solution increased P solubilization. The 2c-cell combined with the higher acid concentration resulted in higher P recoveries, 125g of P/kg of SSA in the anolyte. The obtained results showed that the ED process is a valuable tool for the SSA valorisation as it promotes simultaneous P recovery and metals extraction from the SSA.
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Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Fósforo
/
Esgotos
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Eliminação de Resíduos Líquidos
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Compostos de Ferro
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Conservação dos Recursos Naturais
País/Região como assunto:
Europa
Idioma:
En
Revista:
Waste Manag
Assunto da revista:
SAUDE AMBIENTAL
/
TOXICOLOGIA
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Dinamarca