F Santos Andreia, P Santos Cátia, M Matos Ana, Cardoso Olga, J Quina Margarida
CIEPQPF-Centre of Chemical Processes Engineering and Forest Products, Department of Chemical Engineering, University of Coimbra, 3030-790 Coimbra, Portugal.
CIEPQPF-Centre of Chemical Processes Engineering and Forest Products, Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal.
Microorganisms. 2020 Mar 7;8(3):376. doi: 10.3390/microorganisms8030376.
This work aims to evaluate the microbiological contamination of sewage sludge (SS) collected in urban wastewater treatment plants (WWTP) from Portugal. Two types of SS were considered: urban mixed (UM) and from anaerobic digestion (AD). The two types of samples were characterized in relation to the main physical and chemical parameters, as well as the microbiological contamination ( and spp). Then, sanitation tests were conducted through thermal drying and chemical treatments. Towards a circular economy, industrial alkaline wastes (green liquor dregs - GLD, lime mud, coal fly ash, eggshell) were tested as alternatives to lime. Only six out of nineteen samples complied with the legal limits for both microorganisms. However, drying at 130 °C sanitized selected samples below the limit, regardless of the initial moisture or contamination. Additionally, CaO (obtained from eggshell) led to the complete elimination of at any dosage studied (0.05-0.15 g/g SS). GLD evidenced the ability to reduce contamination at room temperature, but not enough to comply with the legal limit. In general, this work highlights the need to sanitize the SS before its application to the soil, and the positive role of some wastes on this goal.
这项工作旨在评估从葡萄牙城市污水处理厂（WWTP）收集的污水污泥（SS）的微生物污染情况。考虑了两种类型的SS：城市混合污泥（UM）和厌氧消化污泥（AD）。对这两种类型的样品进行了主要物理和化学参数以及微生物污染（ 和 属）方面的表征。然后，通过热干燥和化学处理进行了卫生测试。为了实现循环经济，测试了工业碱性废物（绿液渣 - GLD、石灰泥、粉煤灰、蛋壳）作为石灰的替代品。19个样品中只有6个符合两种微生物的法定限值。然而，在130°C下干燥可使选定样品的卫生状况低于 限值，无论初始水分或污染情况如何。此外，（从蛋壳中获得的）CaO在任何研究剂量（0.05 - 0.15 g/g SS）下都能导致 的完全消除。GLD证明了在室温下降低 污染的能力，但不足以符合法定限值。总体而言，这项工作强调了在将SS应用于土壤之前进行卫生处理的必要性，以及一些废物在实现这一目标方面的积极作用。
