| Autor: |
Zhengxin FEI, Zijie DING, Xuan ZHENG, Liang FENG, Qingyao HE, Shuiping YAN, Long JI |
| Jazyk: |
angličtina |
| Rok vydání: |
2023 |
| Předmět: |
|
| Zdroj: |
Frontiers of Agricultural Science and Engineering, Vol 10, Iss 3, Pp 479-491 (2023) |
| Druh dokumentu: |
article |
| ISSN: |
2095-7505 |
| DOI: |
10.15302/J-FASE-2023480 |
| Popis: |
● LFD was treated by fly ash-based chemical precipitation and CO2 mineralization.● > 93% COD and > 98% TP removal efficiency, and < 2 mS·cm−1 EC was achieved.● COD and TP removal was achieved by co-precipitation during CO2 mineralization.● CO2 mineralization neutralized the alkaline LFD and removed heavy met. Chemical precipitation is a widely applied approach for a liquid fraction of digestate (LFD) of agricultural waste but its large-scale application requires low-cost and efficient precipitating agents and novel process design. This study evaluated novel approach for the efficient removal of contaminants from the LFD using fly ash-based chemical precipitation, followed by filtration and CO2 mineralization. The technical feasibility of this approach was evaluated using pH and electrical conductivity (EC), and removal efficiencies of total phosphorus (TP), chemical oxygen demand (COD) and heavy metals during the treatment. The fly ash used in this study showed a promising performance as a chemical precipitation agent for COD and TP removal from the treated LFD involving complex effects of precipitation and adsorption. CO2 bubbling after fly ash-based chemical precipitation provided further COD and TP removal by carbonation reactions between CO2 and the excessive alkaline minerals in fly ash. Although addition of fly ash to untreated LFD increased pH from 8.3 to 12.9 and EC from 7.01 to 13.7 mS·cm−1, CO2 bubbling helped neutralize the treated LFD and reduce the EC, and concentrations of toxic ions by carbonation reactions. The fly ash-based chemical precipitation and CO2 mineralization had > 93% COD and > 98% TP removal efficiencies, and resulted in an EC of < 2 mS·cm−1 and a neutral pH in the treated LFD, as well as the high purity calcite product. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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