Abstract

This study aimed to evaluate the effect of organic loading rate (OLR) variation on the anaerobic treatment of food waste from a university restaurant in a demonstration-scale set-up. The system was submitted to the academic calendar and seasonal variation of temperature. During 330 days of semi-continuous operation in three different periods (i.e. school-period/fall, school-period/spring and vacation-period/summer), the reactor performance and stability process were analysed. The reactor temperature was not controlled and varied seasonally from 23 to 32 °C. Differently, the OLR and hydraulic retention time (HRT) were controlled by food waste available in the vacation period and by the reactor stability in the school periods, ranging from 0.15 to 0.51 kg VS m⁻³ day⁻¹ for the OLR and from 121 to 230 days for the HRT. The highest average methane production rate and VS removal were 0.12 m³ CH₄ m⁻³ day⁻¹ and 81%, respectively. The results indicated that as the reactor had been operated using non-optimized mixing for six years before the experiment, probably the accumulation of inert materials inside affected its performance. In addition, despite the non-optimized mixing of the reactor, which represented up to 80% of the energy consumed, a net energy ratio of 1.98 was achieved. Throughout the experimental period a total of 15,970 kg of food waste was treated and 375 m³ of methane were produced. Despite the system limitations, the valorization of food waste through anaerobic digestion proved to be possible under simplified operating conditions, i.e. even without pH and temperature control, besides the organic loading rate reduction caused by the vacation period.

Graphic Abstract

中文翻译：

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餐厨垃圾厌氧消化：演示系统中有机负荷变化的影响

摘要

这项研究旨在评估有机负荷率（OLR）变化对示范规模设置中大学餐厅厌氧处理食物垃圾的影响。该系统已提交给学术日历和温度的季节性变化。在三个不同时期（即上学期/秋季，上学期/春季和休假期/夏季）的330天半连续运行过程中，分析了反应堆的性能和稳定性过程。反应器温度不受控制，并且从23到32°C季节性变化。不同的是，OLR和水力停留时间（HRT）由休假期间可利用的食物残渣和学校时段的反应堆稳定性控制，范围为0.15至0.51 kg V​​S m ^-3天^-1对于OLR，对于HRT为121至230天。最高平均甲烷生产率和VS去除分别为0.12 m ³ CH ₄ m ^-3天^-1和81％。结果表明，由于该反应器在实验前已使用非优化混合运行了六年，因此惰性材料的内部堆积可能会影响其性能。另外，尽管反应器的混合不是最优化的，代表了高达80％的能量消耗，但仍实现了1.98的净能量比。在整个实验期间，共处理了15970千克的厨余和375 m ³产生了甲烷。尽管系统存在局限性，但通过简化的操作条件，即使即使没有pH和温度控制，也可以通过厌氧消化对食物残渣进行增值，除了由于休假期导致的有机负荷降低以外。

图形摘要