Guangdong Provincial Key Lab of Environmental Pollution Control and Remediation Technology, School of Environmental Science & Engineering, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, School of Environment, South China Normal University, Guangzhou 510006, China.
Guangdong Provincial Key Lab of Environmental Pollution Control and Remediation Technology, School of Environmental Science & Engineering, Sun Yat-sen University, Guangzhou 510275, China.
Water Res. 2022 Aug 15;222:118852. doi: 10.1016/j.watres.2022.118852. Epub 2022 Jul 12.
Acidic waters such as groundwater, drainage and lakes in mining area contain high-strength acids and metal ions, posing serious threats to aquatic ecosystems and human health. Dissimilatory sulfate reduction (DSR)-based processes are attractive technologies for remediating acidic waters because it produces alkalinity and sulfide for metal precipitation and acid neutralization. However, the effects of pH elevation achieved by DSR-based processes are case-sensitive and difficult to be quantitively assessed, which limits the application of DSR process for acidic water remediation. Therefore, in this study, a Sulfidogenic Acid mine water Remediation Model (SARM) considering the DSR process, weak acids balance, metal sulfide and hydroxide precipitations, and gas-liquid exchanges of HS and CO, was developed to quantitatively assess the effects of various environmental factors on the pH elevation by a DSR process in acidic waters. A long-term trial of a DSR reactor was conducted to calibrate and validate the SARM. The experimental results revealed that the DSR-based process is effective to relieve acidity. The calibrated SARM demonstrated the excellent performance to predict the pH variation in the DSR reactor, under the varied conditions of influent pH and organic concentration. The calibrated SARM was further validated with data collected from literatures, and the results verified that the proposed model is capable to accurately assess the effect of DSR process on acid neutralization and metal removals under various conditions in steady state. The model was employed to systematically evaluate the impacts of environmental factors on acid remediation within a DSR-based process. The results revealed that the background alkalinity plays an important role in acid neutralization. However, with an increase in sulfate reduction, biogenic sulfide and carbonate become the dominant buffering substances to neutralize acidity. Furthermore, the SARM was used to evaluate the applicability of the DSR-based process for the remediation of acidic waters by evaluating the sulfide production thresholds for acid neutralization and metal removal. The simulation results demonstrated that, the DSR-based process is recommended for the remediation of acidic waters with low background alkalinity. Collectively, the SARM proposed in this study was found to be a useful and efficient tool for quantitatively assessing the potential of DSR-based processes for neutralizing acidic waters, which is vital for biogeochemistry and environmental engineering research.
矿区地下水、排水和湖泊等酸性水体含有高强度酸和金属离子，对水生生态系统和人类健康构成严重威胁。基于异化硫酸盐还原（DSR）的过程是修复酸性水体的有吸引力的技术，因为它产生碱度和硫化物用于金属沉淀和酸中和。然而，基于 DSR 的过程所产生的 pH 升高效果是敏感的，难以进行定量评估，这限制了 DSR 过程在酸性水修复中的应用。因此，在这项研究中，开发了一种考虑 DSR 过程、弱酸平衡、金属硫化物和氢氧化物沉淀以及 HS 和 CO 的气液交换的硫化酸性矿山废水修复模型（SARM），以定量评估各种环境因素对酸性水中 DSR 过程引起的 pH 升高的影响。进行了 DSR 反应器的长期试验以校准和验证 SARM。实验结果表明，DSR 基过程有效地缓解了酸度。在进水 pH 和有机浓度变化的条件下，校准的 SARM 表现出了卓越的性能，能够预测 DSR 反应器中的 pH 变化。校准的 SARM 还使用文献中收集的数据进行了验证，结果验证了所提出的模型能够在各种条件下准确评估 DSR 过程对稳态下酸中和和金属去除的影响。该模型用于系统地评估环境因素对基于 DSR 的过程中酸修复的影响。结果表明，背景碱度在酸中和中起着重要作用。然而，随着硫酸盐还原的增加，生物生成的硫化物和碳酸盐成为中和酸度的主要缓冲物质。此外，使用 SARM 评估了基于 DSR 的过程用于修复酸性水的适用性，通过评估酸中和和金属去除的硫化物产生阈值来评估。模拟结果表明，建议在背景碱度低的情况下使用基于 DSR 的过程来修复酸性水。总的来说，本研究中提出的 SARM 被发现是一种用于定量评估基于 DSR 的过程中和酸性水的潜力的有用且高效的工具，这对于生物地球化学和环境工程研究至关重要。
