Neamhom Thanakrit, Yakam Pakasinee, Bathbumrung Chalermkiet, Tachavarong Wirunya, Kosaisavee Varakorn, Pinatha Yada
Department of Environmental Health Sciences, Faculty of Public Health, Mahidol University, Rajvithi Road, Bangkok, 10400, Thailand.
Center of Excellence on Environmental Health and Toxicology (EHT), OPS, MHESI, Bangkok, 10400, Thailand.
Sci Rep. 2025 Jan 28;15(1):3477. doi: 10.1038/s41598-025-87520-8.
The objective of this study is to enhance the capacity of struvite-phosphate forming reactor utilized in the production of phosphorus fertilizer from wastewater collected from mobile toilets, characterized by phosphorus (P) concentrations of 5.0 ± 1.1 g/l. The experimental procedure comprised three sequential phases: the first phase involved the precipitation of struvite-phosphate using the forming reactor; the second phase focused on pelletizing the P product with sugar milling wastes as filler; and the third phase involved assessing the bioavailability of P in agricultural soils. Experimental design entails batch experiments with the operational variables including the Mg:P molar ratio and pH. Results from nine experiments (3 × 3) indicate that (1) the percentage of phosphorus recovery ranged from 1.9 to 65.2, with a peak observed at high pH values, (2) optimal phosphorus recovery is attained at Mg:P ratio of 1.25 and pH of 9 during precipitation, and (3) the EDS analysis confirms the presence of major elements with phosphorus constituting the predominant component at 13.1%weight. Moreover, P leaching in soil predominantly occurred after the 7th day among the various soil types with the 90-days dissolution efficiency in soil of 97.7 ± 0.6, 86.9 ± 4.1, and 88.0 ± 3.0 for sandy loam, silt loam, and clay loam, respectively. These findings underscore the viability of achieving substantial phosphorus recovery through the utilization of a struvite-phosphate forming reactor via chemical precipitation, with additional evidence suggesting effective leaching of pellets in sandy loam soil, thereby highlighting its potential for widespread implementation in both phosphorus recovery and struvite fertilizer production on a large scale.
本研究的目的是提高用于从移动厕所收集的废水中生产磷肥的鸟粪石-磷酸盐形成反应器的能力，该废水的磷（P）浓度为5.0±1.1 g/l。实验过程包括三个连续阶段：第一阶段使用形成反应器沉淀鸟粪石-磷酸盐；第二阶段以制糖废料为填料对磷产物进行造粒；第三阶段评估农业土壤中磷的生物有效性。实验设计包括使用包括镁磷摩尔比和pH值在内的操作变量进行批次实验。九个实验（3×3）的结果表明：（1）磷回收率在1.9%至65.2%之间，在高pH值时出现峰值；（2）沉淀过程中镁磷比为1.25且pH值为9时可实现最佳磷回收；（3）能谱分析证实了主要元素的存在，其中磷占主要成分，重量百分比为13.1%。此外，在不同土壤类型中，磷在土壤中的淋溶主要发生在第7天之后，砂壤土、粉砂壤土和粘壤土在土壤中的90天溶解效率分别为97.7±0.6、86.9±4.1和88.0±3.0。这些发现强调了通过利用鸟粪石-磷酸盐形成反应器通过化学沉淀实现大量磷回收的可行性，另有证据表明颗粒在砂壤土中有效淋溶，从而突出了其在大规模磷回收和鸟粪石肥料生产中广泛应用的潜力。
