###### Abstract  
This study investigated the Zaalkalapspruit valley bottom wetland in South Africa, an ecologically engineered site influenced by acid mine drainage (AMD) from a defunct coal mine upstream. Conducted in 2022, the research aimed to elucidate the dynamics of contaminant dispersal within this wetland, focusing on the sources, pathways, and receptors of metals and sulfur compounds. The analysis revealed that the wetland's bottom sediment is rich in organic material, with pH values ranging from 6.05 to 6.59 and low oxidation-reduction potentials reaching \(-\)219.67 mV at Site S3. The significant findings included the highest adsorption rates of manganese, contrasted with iron, which was primarily absorbed by the roots of _Typha capensis_ and the algae _Klebsormidium acidophilum_. The macrophtye rhizosphere were found to host diverse microbiota, including families such as _Helicobacteraceae_ and _Hydrogenophilaceu_, pivotal in metal and sulfur processing. This study highlighted the complex biogeochemical interactions involving sediment, macrophtye root systems, perippython, and microbial populations. These interactions demonstrate the efficacy of ecologically engineered wetlands in mitigating the impacts of acid mine drainage, underscoring their potential for environmental remediation. Importantly, the sustainability of such interventions highlights the need for community involvement and acceptance, acknowledging that local support is essential for the long-term success of ecological engineering solutions that address environmental challenges like AMD. ecological engineering; acid mine drainage; wetland remediation; biogeochemical processes; contaminant dynamics +
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The remediation of AMD poses significant challenges for the mining sector and environmental professionals worldwide, attributed to its severe impacts and variable site characteristics [9; 10]. AMD originates from the oxidation of pyrite (FeS2) when water interacts with metals and coal in mining operations, which results in the production of sulfuric acid, hydrogen ions, and mobilized metals [9; 11].Water affected by AMD typically exhibits low pH levels and elevated concentrations of harmful elements and metals such as aluminum (Al), iron (Fe), manganese (Mn), and sulfate (SO4\({}^{2-}\)) [11]. Such contamination may spread to nearby aquatic systems, consequently degrading soil and plant life and presenting substantial risks to public health and safety when the contaminated water is used for consumption [12]. The impact of AMD on water quality extends to both proximal and distant ecosystems, with the potential for water resource contamination lingering for decades post-mining operations [13; 14]. The treatment of AMD water typically focuses on elevating the pH through neutralization and is divided into two fundamental approaches: active and passive treatment systems [9; 15]. Active treatment strategies involve the deliberate addition of chemical alkaline agents to promote metal precipitation, whereas passive treatments harness natural processes--including physical, chemical, biological, and geological methods--to alleviate acidity [16; 17; 18; 19]. Among these, passive treatment systems are lauded for their environmental compatibility and their added ecological advantages, positioning them as essential elements of sustainable environmental practices [15; 20; 21]. Ecosystem restoration involves reverting degraded ecosystems to conditions that resemble their original natural states, incorporating strategies such as wetland restoration, regeneration and rehabilitation [2; 22]. Within the realm of environmental management, ecological engineering is pivotal to these restoration and even regeneration efforts [23]. Adopting a holistic and non-linear perspective, ecological engineering applies engineering solutions to environmental challenges in a sustainable manner [24; 25].