United Nations University, Institute for Integrated Management of Material Fluxes and of Resources (UNU-FLORES), Ammonstraße 74, 01067, Dresden, Germany; Technische Universität Dresden, Institute of Groundwater Management, 01069 Dresden, Germany.
Technische Universität Dresden, Institute of Groundwater Management, 01069 Dresden, Germany.
Chemosphere. 2020 Jan;239:124741. doi: 10.1016/j.chemosphere.2019.124741. Epub 2019 Sep 3.
In many parts of the world, wastewater irrigation has become a common practice because of freshwater scarcity and to increase resource reuse efficiency. Wastewater irrigation has positive impacts on livelihoods and at the same time, it has adverse impacts related to environmental pollution. Hydrochemical processes and groundwater behaviour need to be analyzed for a thorough understanding of the geochemical evolution in the wastewater irrigated systems. The current study focuses on a micro-watershed in the peri-urban Hyderabad of India, where farmers practice intensive wastewater irrigation. To evaluate the major factors that control groundwater geochemical processes, we analyzed the chemical composition of the wastewater used for irrigation and groundwater samples on a monthly basis for one hydrological year. The groundwater samples were collected in three settings of the watershed: wastewater irrigated area, groundwater irrigated area and upstream peri-urban area. The collected groundwater and wastewater samples were analyzed for major anions, cations and nutrients. We systematically investigated the anthropogenic influences and hydrogeochemical processes such as cation exchange, precipitation and dissolution of minerals using saturated indices, and freshwater-wastewater mixtures at the aquifer interface. Saturation indices of halite, gypsum and fluorite are exhibiting mineral dissolution and calcite and dolomite display mineral precipitation. Overall, the results suggest that the groundwater geochemistry of the watershed is largely controlled by long-term wastewater irrigation, local rainfall patterns and water-rock interactions. The study results can provide the basis for local decision-makers to develop sustainable groundwater management strategies and to control the aquifer pollution influenced by wastewater irrigation.
在世界许多地区，由于淡水短缺和提高资源再利用效率，污水灌溉已成为一种常见做法。污水灌溉对生计有积极影响，但同时也存在与环境污染相关的不利影响。为了全面了解污水灌溉系统中的地球化学演化，需要分析水化学过程和地下水行为。本研究集中在印度海得拉巴周边的一个小流域，那里的农民大量进行污水灌溉。为了评估控制地下水地球化学过程的主要因素，我们每月对灌溉污水和地下水样本进行了为期一个水文年的分析。地下水样本采集于流域的三个区域：污水灌溉区、地下水灌溉区和城市周边上游区。收集的地下水和污水样本用于分析主要阴离子、阳离子和营养物质。我们使用饱和指数系统地研究了人为影响和水文地球化学过程，如阳离子交换、矿物沉淀和溶解，以及含水层界面处的淡水-污水混合。岩盐、石膏和萤石的饱和度指数显示矿物溶解，而方解石和白云石则显示矿物沉淀。总体而言，结果表明，流域的地下水地球化学主要受长期污水灌溉、当地降雨模式和水岩相互作用控制。研究结果可为当地决策者制定可持续地下水管理策略以及控制受污水灌溉影响的含水层污染提供依据。
