Enhancing chemical phosphorus precipitation from tapioca starch anaerobic digestion effluent in a modified pilot-scale fluidized bed reactor
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Issued Date
2023-08-15
Resource Type
ISSN
00139351
eISSN
10960953
Scopus ID
2-s2.0-85160745175
Journal Title
Environmental Research
Volume
231
Rights Holder(s)
SCOPUS
Bibliographic Citation
Environmental Research Vol.231 (2023)
Suggested Citation
Riewklang K., Polprasert C., Nakason K., Polprasert S., Kwonpongsagoon S., Mahasandana S., Panyapinyopol B. Enhancing chemical phosphorus precipitation from tapioca starch anaerobic digestion effluent in a modified pilot-scale fluidized bed reactor. Environmental Research Vol.231 (2023). doi:10.1016/j.envres.2023.116277 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/82980
Title
Enhancing chemical phosphorus precipitation from tapioca starch anaerobic digestion effluent in a modified pilot-scale fluidized bed reactor
Author's Affiliation
Other Contributor(s)
Abstract
This study aimed to evaluate the possibility of P precipitation as struvite from real anaerobic digestion (AD) effluent of tapioca starch processing. The results showed that at a pH of 9, and without Mg:P molar adjustment, P recovery was at 85%. The percentage of P recovery was increased to 90% and P contained in precipitates was at 11.80–14.70 wt% P, which is higher than commercial single superphosphate fertilizer (SSP, 18–22 wt% P2O5). This was achieved by controlling mixing at 200–400 rpm and upflow velocity at 50–200 cm min−1 inside a fluidized bed reactor (FBR). Based on SEM-EDX, powder XRD, phase identification by profile matching, and FT-IR analysis, the results demonstrated that recovered precipitates formed struvite predominantly. In addition, results of the woodchip ash additions and the one-way ANOVA based-RSM analysis revealed that mixing, the solution pH, and the woodchip ash intensely affected P recovery with the optimum condition found at 400 rpm, pH9, 4 g L−1, respectively. Ash addition enhanced P recovery efficiency but decreased the product's purity. Total costs of P recovery varied considerably from 0.28 to 7.82 USD∙(kg P)−1 depending on chemical consumption and %P content in recovered products. Moreover, the total cost was reduced by 57% from 7.82 USD∙(kg P)−1 (profit margin: −4.30 to −2.82) by a single mixing operation to 3.35 USD∙(kg P)−1 (profit margin: +0.17 to +1.65) employing coupling effect of mixing and Vup. The results indicate that P recovery from tapioca starch AD effluent not only provides a good-quality alternative slow-release P fertilizer, but also helps to curtail environmental problems due to excessive P and nitrogen discharge. These findings also demonstrate the ways of recovering nutrients from an abundant renewable resource that are relevant to simultaneous waste utilization during pollution controls.