The requirement of trace elements (TE) in anaerobic digestion process is widely documented. However, little is understood regarding the specific requirement of elements and their critical concentrations under different operating conditions such as substrate characterisation and temperature.In this study, a flask batch trial using fractional factorial design is conducted to investigate volatile fatty acids (VFA) anaerobic degradation rate under the influence of the individual and combined effect of six TEs (Co, Ni, Mo, Se, Fe and W). The experiment inoculated with food waste digestate, spiked with sodium acetate and sodium propionate both to 10 g/l. This is followed by the addition of a selection of the six elements in accordance with a 2⁶⁻² fractional factorial principle. The experiment is conducted in duplicate and the degradation of VFA is regularly monitored.Factorial effect analysis on the experimental results reveals that within these experimental conditions, Se has a key role in promoting the degradation rates of both acetic and propionic acids; Mo and Co are found to have a modest effect on increasing propionic acid degradation rate. It is also revealed that Ni shows some inhibitory effects on VFA degradation, possibly due to its toxicity. Additionally, regression coefficients for the main and second order effects are calculated to establish regression models for VFA degradation.

中文翻译：

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使用分数阶乘实验设计研究微量元素对厌氧挥发性脂肪酸降解的影响

厌氧消化过程中对痕量元素（TE）的需求已被广泛记录。但是，对于不同操作条件下元素的具体要求及其临界浓度（例如底物表征和温度）知之甚少。在这项研究中，使用分数阶乘设计进行了烧瓶批量试验，以研究挥发性脂肪酸（VFA）厌氧降解速率受六个TE（钴，镍，钼，硒，铁和钨）的个体和联合效应的影响。该实验接种了食物残渣消化液，掺入乙酸钠和丙酸钠的浓度均为10 g / l。接下来是根据2 ^6−2添加六个元素的选择分数阶乘原理。实验进行两次，并定期监测VFA的降解情况。对实验结果的分解作用分析表明，在这些实验条件下，Se对促进乙酸和丙酸的降解速率具有关键作用。发现Mo和Co对增加丙酸降解速率具有适度的影响。还发现Ni可能对VFA降解显示出某些抑制作用，这可能是由于其毒性。另外，计算主效应和二阶效应的回归系数以建立VFA降解的回归模型。