Departamento de Hidráulica e Saneamento e Escola de Engenharia de São Carlos, Universidade de São Paulo (SHS/EESC/USP), Av. Trabalhador São-Carlense 400, 13566-590, São Carlos, SP, Brazil.
Laboratório de Biotecnologia Anaeróbia, Instituto de Ciência e Tecnologia, Universidade Federal de Alfenas (UNIFAL-MG), Rodovia José Aurélio Vilela, 11999 (BR 267, Km 533), 37715-400, Poços de Caldas, MG, Brazil.
Biodegradation. 2019 Feb;30(1):47-58. doi: 10.1007/s10532-018-9863-8. Epub 2018 Nov 8.
Acid mine drainage (AMD) is among the most serious threats to water and the typical alkali-based treatment costs are high. This study's main objective was the establishment of a highly efficient biological process using an upflow anaerobic sludge blanket (UASB) reactor to treat AMD based on a shorter hydraulic retention time (HRT) and lower organic matter input. The process was evaluated for a long-term operation (739 days) in terms of the influence of HRT (14-24 h), metal addition, sulfate loading rate (0.5-2.6 g SO l d), and the COD/SO ratio (0.67-1.0) using ethanol as the only electron donor at a pH of 4.0. Neutral effluent pH was achieved throughout the time apart from operational modifications. The reduction in HRT from 24 to 16 h and an increase in the sulfate loading rate (SLR) up to 2.25 g SO l d improved the sulfate removal to (92.1 ± 1.8)% with 80% chemical oxygen demand (COD) removal. However, the sulfate reduction was less than 80% when the HRT and SLR was changed to 14 h and 2.6 g SO l d, respectively. The oxidation of organic matter by sulfate reduction was greater than 50% regardless of the conditions imposed but the use of ethanol to treat AMD was more efficient when either the HRT was 16 h (1.5 g SO l d) in the presence of Fe, Zn, and Cu or the HRT was 14 h (2.6 g SO l d) but the COD/SO ratio was reduced to 0.67. The fully optimized conditions of the UASB reactor were set at an HRT of 16 h, SLR of 1.5 g SO l d, and a COD/SO ratio of 1.0.
酸性矿山排水 (AMD) 是对水的最严重威胁之一，而典型的碱性处理方法成本很高。本研究的主要目的是建立一个高效的生物处理过程，使用上流式厌氧污泥床 (UASB) 反应器，以较短的水力停留时间 (HRT) 和较低的有机物输入处理 AMD。该过程在长期运行 (739 天) 中，根据 HRT (14-24 小时)、金属添加、硫酸盐负荷率 (0.5-2.6 g SO l d) 和 COD/SO 比 (0.67-1.0) 的影响进行了评估，使用乙醇作为唯一电子供体，在 pH 值为 4.0 时运行。除了操作修改外，整个时间内都实现了中性流出物 pH 值。将 HRT 从 24 小时减少到 16 小时，并将硫酸盐负荷率 (SLR) 提高到 2.25 g SO l d，将硫酸盐去除率提高到 (92.1 ± 1.8)%，同时去除 80%的化学需氧量 (COD)。然而，当 HRT 和 SLR 分别变为 14 小时和 2.6 g SO l d 时，硫酸盐还原率低于 80%。无论施加何种条件，硫酸盐还原对有机物的氧化都大于 50%，但使用乙醇处理 AMD 时，在 HRT 为 16 小时（存在 Fe、Zn 和 Cu 时为 1.5 g SO l d）或 HRT 为 14 小时（但 COD/SO 比降低至 0.67）时，效率更高。UASB 反应器的完全优化条件设定为 HRT 为 16 小时、SLR 为 1.5 g SO l d 和 COD/SO 比为 1.0。
