Background

Two-phase anaerobic co-digestion (TAcoD) is a versatile technology for the simultaneous treatment of organic materials and biogas production. However, the produced digestate and supernatant of the system contain heavy metals and organic substances that need to be treated prior to discharge or land application. Therefore, in this study, an innovative TAcoD for organic fertilizer and high supernatant quality achievement was proposed.

Methods

In the conventional TAcoD, mixed sewage sludge (SS) and food waste (FW) were first hydrolyzed in the acidogenic reactor, and then the hydrolyzate substrate was subjected to the methanogenic reactor (TAcoD 1). In the modified TAcoD (TAcoD 2), only FW was fed into the acidogenic reactor, and the produced hydrolyzed solid was directly converted to the organic fertilizer, while the supernatant with high soluble chemical demand (SCOD) concentration was further co-digested with SS in the methanogenic reactor.

Results

Although TAcoD 1 produced bio-methane yield and potential energy of 56.18% and 1.6-fold higher than TAcoD 2, the economical valorization of TAcoD 2 was 9-fold of that from TAcoD 1. The supernatant quality of TAcoD 2 was far better than TAcoD 1, since the SCOD, total nitrogen (TN), and total phosphor (TP) removal in TAcoD 2 and TAcoD 1 were 94.3%, 79.4%, 90.7%, and 68.9%, 28%, 46%, respectively. In terms of solid waste management, the modified TAcoD converted FW to organic fertilizer and achieved a solid reduction of 43.62% higher than that of conventional TAcoD.

Conclusions

This new modification in two-phase anaerobic co-digestion of food waste and sewage sludge provides a potentially feasible practice for simultaneous bio-methane, organic fertilizer, and high supernatant quality achievement.

Graphical abstract

中文翻译：

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一种增强餐厨垃圾和污水污泥传统两相厌氧共消化的新方法

背景

两相厌氧共消化 (TAcoD) 是一种多功能技术，可同时处理有机材料和沼气生产。然而，系统产生的消化液和上清液含有重金属和有机物质，需要在排放或土地应用之前进行处理。因此，在本研究中，提出了一种创新的有机肥TAcoD和高上清液质量成果。

方法

在传统的TAcoD中，混合的污水污泥（SS）和食物垃圾（FW）首先在产酸反应器中水解，然后水解产物底物进入产甲烷反应器（TAcoD 1）。在改良的TAcoD（TAcoD 2）中，仅将FW送入产酸反应器，产生的水解固体直接转化为有机肥，而具有高可溶性化学需求（SCOD）浓度的上清液与SS进一步共消化在产甲烷反应器中。

结果

虽然 TAcoD 1 的生物甲烷产量和势能为 56.18%，比 TAcoD 2 高 1.6 倍，但 TAcoD 2 的经济价值是 TAcoD 1 的 9 倍。TAcoD 2 的上清液质量远优于 TAcoD如图 1 所示，由于 TAcoD 2 和 TAcoD 1 中的 SCOD、总氮 (TN) 和总磷 (TP) 去除率分别为 94.3%、79.4%、90.7% 和 68.9%、28%、46%。在固废管理方面，改良的TAcoD将FW转化为有机肥，实现了比传统TAcoD高出43.62%的固废。

结论

这种对食物垃圾和污水污泥的两相厌氧共消化的新改进为同时实现生物甲烷、有机肥和高上清液质量提供了潜在的可行实践。

图形概要