National Research Council of Italy, Institute for Agricultural and Forest Systems in the Mediterranean, Via della Madonna Alta 128, 06123, Perugia, Italy.
Centro de Estudios e Investigaciones Ambientales (CEIAM), Universidad Industrial de Santander, Carrera 27, Calle 9, Bucaramanga, Colombia.
J Environ Manage. 2024 Sep;368:122164. doi: 10.1016/j.jenvman.2024.122164. Epub 2024 Aug 13.
Digestates from low-tech digesters need to be post-treated to ensure their safe agricultural reuse. This study evaluated, for the first time, vermifiltration as a post-treatment for the digestate from a low-tech digester implemented in a small-scale farm, treating cattle manure and cheese whey under psychrophilic conditions. Vermifiltration performance was monitored in terms of solids, organic matter, nutrients, and pathogens removal efficiency. In addition, the growth of earthworms (Eisenia foetida) and their role in the process was evaluated. Finally, the vermicompost and the effluent of the vermifilter were characterized in order to assess their potential reuse in agriculture. Vermifilters showed high removal efficiency of chemical oxygen demand (55-90%), total solids (60-80%), ammonium nitrogen (83-97%), and phosphate-P (28-49%). Earthworms effectively grew and reproduced on digestate (i.e. earthworms number increased by 183%), enhancing the vermifiltration performance, while reducing clogging and odour-related issues. Both the vermicompost and effluent produced complied with legislation limits established for soil improvers and wastewater for fertigation, respectively. Indeed, there was an absence of pathogens and non-detectable heavy metals concentrations. Vermifiltration may be thus considered a suitable post-treatment option for the digestate from low-tech digesters, allowing for its safe agricultural reuse and boosting the circular bioeconomy in small-scale farms.
来自低技术消化器的消化物需要进行后处理，以确保其在农业中的安全再利用。本研究首次评估了在小型农场中实施的低温消化器的消化物的后处理方法——蚯蚓过滤法，该方法处理牛粪便和奶酪乳清，并在低温条件下进行。从固体、有机物、养分和病原体去除效率方面监测了蚯蚓过滤性能。此外，还评估了蚯蚓（赤子爱胜蚓）的生长及其在该过程中的作用。最后，对蚯蚓滤器的粪肥和滤液进行了特征描述，以评估其在农业中的潜在再利用价值。蚯蚓过滤法对化学需氧量（55-90%）、总固体（60-80%）、铵态氮（83-97%）和正磷酸盐-P（28-49%）具有很高的去除效率。蚯蚓有效地在消化物上生长和繁殖（即蚯蚓数量增加了 183%），从而提高了蚯蚓过滤性能，同时减少了堵塞和气味相关问题。生成的粪肥和滤液均符合分别为土壤改良剂和灌溉施肥废水设定的法规限制。实际上，没有检测到病原体和重金属浓度。因此，蚯蚓过滤法可以被认为是低技术消化器消化物的一种合适的后处理选择，允许其安全地在农业中再利用，并促进小型农场的循环生物经济。
