Publicação
Combined pretreatment by ultrasound and struvite precipitation of raw substrates: A strategy to overcome C/N ratio unbalance in nitrogen-rich anaerobic co-digestion systems
| Resumo: | The present study aimed to optimize the struvite chemical precipitation process in nitrogenrich anaerobic co-digestion systems. Struvite precipitation experiments were carried out using a mixture of cattle slurry liquid fraction and sewage sludge, with and without ultrasound pretreatment. Marine salt or MgCl2 were used as magnesium source in NH4 + :Mg2+ stoichiometric proportions of 1:1.5 and 1:3. Under the tested conditions, ammonium nitrogen and orthophosphate were removed from the mixed liquor with a maximum observed efficiency of 43% and 92%, respectively, when the ultrasound treatment was applied prior to struvite precipitation, using MgCl2 as source of magnesium (NH4 + :Mg2+ of 1:3). The operating time was 40 min. Different pretreatments were tested prior to the biomethanization experiments, struvite precipitation, ultrasound, or a combination of both pretreatments. The application of ultrasound (with an energy input of 218 kJ L−1 ) and struvite precipitation (NH4 + :Mg2+ of 1:3) increased the methane content in the biogas by 82% and reduced hydraulic retention time by 28%, when compared to the anaerobic co-digestion assays without pretreatment. The hydrolytic pretreatment increased the bioavailability of nitrogen by 5%, thus enhancing the removal efficiency of ammonium nitrogen by 20%. Consequently, an increase in the carbon to nitrogen ratio was observed, favoring the methanogenesis process. |
|---|---|
| Autores principais: | Coura, Renata D'arc |
| Outros Autores: | Rodrigues, Ana Cristina; Alonso, Joaquim Mamede; Ferraz, Ana Isabel; Brito, Luis Miguel; Abrantes, João C. C.; Brito, António Guerreiro |
| Assunto: | Ultrasound pretreatment Struvite precipitation Nutrient recovery Circular economy Anaerobic (co)digestion |
| Ano: | 2021 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Instituto Politécnico de Viana do Castelo |
| Idioma: | inglês |
| Origem: | Repositório Científico IPVC |
| Resumo: | The present study aimed to optimize the struvite chemical precipitation process in nitrogenrich anaerobic co-digestion systems. Struvite precipitation experiments were carried out using a mixture of cattle slurry liquid fraction and sewage sludge, with and without ultrasound pretreatment. Marine salt or MgCl2 were used as magnesium source in NH4 + :Mg2+ stoichiometric proportions of 1:1.5 and 1:3. Under the tested conditions, ammonium nitrogen and orthophosphate were removed from the mixed liquor with a maximum observed efficiency of 43% and 92%, respectively, when the ultrasound treatment was applied prior to struvite precipitation, using MgCl2 as source of magnesium (NH4 + :Mg2+ of 1:3). The operating time was 40 min. Different pretreatments were tested prior to the biomethanization experiments, struvite precipitation, ultrasound, or a combination of both pretreatments. The application of ultrasound (with an energy input of 218 kJ L−1 ) and struvite precipitation (NH4 + :Mg2+ of 1:3) increased the methane content in the biogas by 82% and reduced hydraulic retention time by 28%, when compared to the anaerobic co-digestion assays without pretreatment. The hydrolytic pretreatment increased the bioavailability of nitrogen by 5%, thus enhancing the removal efficiency of ammonium nitrogen by 20%. Consequently, an increase in the carbon to nitrogen ratio was observed, favoring the methanogenesis process. |
|---|