In the present study, the possibility of recovering both thermal energy and water for agricultural purposes from sewage is evaluated. A treatment plant, based on a sequencing batch biofilter granular reactor (SBBGR) followed by sand filtration and coupled with a solar wastewater source heat pump, was operated from September to November 2018 at a set-point temperature of 14 °C to verify the stability of heat recovery efficiency and the suitability of plant effluent to be reused for irrigation. Heat recovery did not influence the SBBGR treatment and disinfection efficiency, which removed about 90% of suspended solids, chemical and biochemical oxygen demand and ammonia, as well as 70% of total nitrogen, 3 log10 units of Escherichia coli and more than 1 log10 unit of Clostridium perfringens. Furthermore, after sand filtration, water quality complied with the standards for agricultural reuse currently in force in several countries. Energy extracted from SBBGR was mainly influenced by environmental conditions, affecting wastewater temperature, and also by wastewater composition, affecting the energy release due to bacterial metabolic activity for carbon and nitrogen removal. Notably, no evident deterioration of energy extraction efficiency from the SBBGR was observed, suggesting negligible fouling phenomena on the submerged thermal exchanger.

中文翻译：

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从城市污水中回收水和能量的好氧颗粒技术

在本研究中，评估了从污水中回收热能和水用于农业用途的可能性。2018 年 9 月至 11 月，基于序批式生物过滤颗粒反应器 (SBBGR) 和砂滤结合太阳能废水源热泵的处理厂在 14 °C 的设定点温度下运行，以验证稳定性热回收效率和植物废水重新用于灌溉的适宜性。热回收不影响 SBBGR 处理和消毒效率，去除了约 90% 的悬浮物、化学和生化需氧量和氨，以及 70% 的总氮、3 log10 单位的大肠杆菌和 1 log10 单位以上的大肠杆菌产气荚膜梭菌。此外，经过砂滤后，水质符合目前在几个国家实施的农业再利用标准。从 SBBGR 提取的能量主要受环境条件的影响，影响废水温度，也受废水成分的影响，由于细菌代谢活动去除碳和氮，影响能量释放。值得注意的是，没有观察到 SBBGR 的能量提取效率明显下降，表明浸没式换热器上的结垢现象可以忽略不计。