Minera La Zanja SRL, Cajamarca, Peru.
Amphos 21 Consulting Peru SAC, San Borja, Lima, Peru.
J Environ Manage. 2019 Aug 15;244:154-160. doi: 10.1016/j.jenvman.2019.05.040. Epub 2019 May 20.
One of the major environmental concerns in the mining industry is the generation of acid leachates from tailings deposits, which are highly concentrated in potentially hazardous elements. The continuous processing of these leachates in treatment plant is unsustainable, so the in situ chemical improvement of the mine wastes and their leachates, mainly with another waste produced in the mining area, can reduce treatment and operational costs. This study aimed to evaluate the effect of two types of domestic wastewaters (DWW) on the improvement of the chemical characteristics of the leachates generated from mine wastes containing sulfides. A mesocosm assay was performed under greenhouse and controlled conditions with mine wastes collected in La Zanja mining area (Peru). Three irrigation treatments were tested: untreated DWW, treated DWW and water as control. Percolated leachates of each treatment were collected once per week, for a period of 10 weeks. Electrical conductivity, pH and multi-elemental concentration were analysed. During the assay, the mine wastes generated acid leachates (≈4) with significant concentrations of elements (mg/L; Al: 1.4-30.0; Cd: 0.05-0.19; Cu: 5.7-22.1; Fe: 1.6-19.4; Mn: 2.6-26.0; Zn: 1.2-9.2) and sulfates (204.3-997.8 mg/L), which exceed the thresholds established by Peruvian legislations. After DWW application, pH in the leachates increased to ≈7 and concentrations of several studied elements (e.g. Al, As, Fe, Cu, Zn, Cd, Pb, Ni, Mn) and sulfates decreased (>70% depending on DWW type, element and sampling) compared to the control. This fact allowed that the Environmental Quality standards from Peru (except for Cu and Mn) were reached. However, an enrichment of Na and K was obtained at the same leachates. At short term, the DWW application (especially untreated) on the mine wastes containing sulfides was effective in the improvement of the general chemical quality of their leachates. Moreover, the combined management of these two studied wastes (domestic wastewater and mine wastes) represents a promising cost-effective strategy during mining operation.
采矿行业的主要环境问题之一是尾矿库产生的酸性浸出液，这些浸出液中含有高度浓缩的潜在有害元素。在处理厂中连续处理这些浸出液是不可持续的，因此可以通过原位化学改良矿山废物及其浸出液（主要是利用矿区产生的另一种废物）来降低处理和运营成本。本研究旨在评估两种类型的生活污水（DWW）对含有硫化物的矿山废物浸出液化学特性改善的影响。在温室和控制条件下，使用在秘鲁拉赞哈矿区收集的矿山废物进行了中规模试验。测试了三种灌溉处理方法：未处理的 DWW、处理过的 DWW 和水作为对照。每周收集一次每种处理方法的渗滤液，共收集 10 周。分析了电导率、pH 值和多元素浓度。在试验过程中，矿山废物产生了酸性浸出液（≈4），其中含有大量的元素（mg/L；Al：1.4-30.0；Cd：0.05-0.19；Cu：5.7-22.1；Fe：1.6-19.4；Mn：2.6-26.0；Zn：1.2-9.2）和硫酸盐（204.3-997.8 mg/L），这些浓度超过了秘鲁法规规定的阈值。在应用 DWW 后，浸出液的 pH 值增加到约 7，与对照相比，几种研究元素（如 Al、As、Fe、Cu、Zn、Cd、Pb、Ni、Mn）和硫酸盐的浓度降低（取决于 DWW 类型、元素和采样，降幅超过 70%）。这一事实使得秘鲁的环境质量标准（除了 Cu 和 Mn）得以达到。然而，在同一浸出液中获得了 Na 和 K 的富集。在短期内，将 DWW（尤其是未经处理的 DWW）应用于含有硫化物的矿山废物中，有效地改善了其浸出液的总体化学质量。此外，对这两种研究废物（生活污水和矿山废物）的联合管理代表了在采矿作业期间具有成本效益的有前途的策略。
