Comparison of heavy metal accumulation in a natural wetland and constructed wetlands receiving acid mine drainage

Abstract The main point of this research is to assess the applicability of condensed molasses soluble (CMS), which is an organic by-product of lysine fermentation, as an environmentally friendly complexing agent in rhizofiltration of heavy metal contaminated acid mine drainage (AMD). First, the ecotoxicological properties (growth inhibition, seed germination) of CMS were examined with often applied indicator plant species such as duckweed (Lemna minor) and lettuce (Lactuca sativa) so as to define the possible applicable CMS concentration. Then the heavy metal accumulation and translocation properties of root accumulator plant species, i.e. common reed (Phragmites australis) and sedge (Carex flacca), were studied to optimize CMS concentration for rhizofiltration. Due to the CMS application, significant increase in bioaccumulation was detected in the case of every examined heavy metal (As, Cd, Cu, Pb and Zn) at the end of the experiment. Results also showed that CMS increased the heavy metal concentration in shoots, but did not affect the root accumulation characteristics of the plants. Furthermore, CMS treated plants accumulated heavy metals at higher rates in their roots compared to control. The results suggest that CMS is a viable additive and a complexing agent to aid rhizofiltration of heavy metal contaminated AMD.

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Attenuation of pollution arising from acid mine drainage by a natural wetland on the Witwatersrand

South African Journal of Science ◽

10.17159/sajs.2017/20160237 ◽

2017 ◽

Vol Volume 113 (Number 1/2) ◽

Cited By ~ 6

Author(s):

Marc S. Humphries ◽

Terrence S. McCarthy ◽

Letitia Pillay ◽

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...

Keyword(s):

Acid Mine Drainage ◽

Metal Accumulation ◽

Mine Drainage ◽

Distal Portion ◽

Contaminated Water ◽

Natural Wetland ◽

Mining Operations ◽

Acid Mine ◽

Pollutant Sources

Abstract Wetlands are well known to be efficient at sequestering pollutants from contaminated water. We investigated metal accumulation in the peats of the Klip River, a natural wetland that has received contaminated water from gold mining operations in Johannesburg for over 130 years. Previous work conducted in the downstream portion identified the wetland as an important system for sequestering metals. We focused on the upstream section of the wetland, more proximal to the source of acid mine drainage, to provide a better understanding of the pollutant sources and the role of the wetland in pollutant attenuation. Geochemical and mineralogical analyses of peat cores revealed considerable metal enrichments in the peat ash, particularly in Co, Ni, Zn, Pb, Cu and U. Metal concentrations are typically between 4 to 8 times higher than those previously reported for the downstream, more distal portion of the wetland. The distribution of metal accumulation within the peat profiles suggests that contamination arises from a combination of sources and processes. Elevated concentrations in the shallow peat are attributed to the input of contaminated surface water via tributaries that drain the Central Rand Goldfield, whereas enrichments in the deeper peat suggest significant sub-surface inflow of contaminated water through the underlying dolomitic rocks. Metal immobilisation occurs through a combination of mechanisms, which include the precipitation of gypsum, metal sulfides, Fe-Mn oxyhydroxides and phosphates. Our study highlights the environmental and economic importance of natural wetland systems which have the ability to accumulate large quantities of metals and thus remediate polluted waters.

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Review of Constructed Wetlands for Acid Mine Drainage Treatment

Water ◽

10.3390/w10111685 ◽

2018 ◽

Vol 10 (11) ◽

pp. 1685 ◽

Cited By ~ 17

Author(s):

Aurora Pat-Espadas ◽

Rene Loredo Portales ◽

Leonel Amabilis-Sosa ◽

Gloria Gómez ◽

Gladys Vidal

Keyword(s):

Heavy Metal ◽

Acid Mine Drainage ◽

Constructed Wetlands ◽

Mine Drainage ◽

Metal Removal ◽

Water Solution ◽

Heavy Metal Removal ◽

Systems Design ◽

Economic Point ◽

Acid Mine

The mining industry is the major producer of acid mine drainage (AMD). The problem of AMD concerns at active and abandoned mine sites. Acid mine drainage needs to be treated since it can contaminate surface water. Constructed wetlands (CW), a passive treatment technology, combines naturally-occurring biogeochemical, geochemical, and physical processes. This technology can be used for the long-term remediation of AMD. The challenge is to overcome some factors, for instance, chemical characteristics of AMD such a high acidity and toxic metals concentrations, to achieve efficient CW systems. Design criteria, conformational arrangements, and careful selection of each component must be considered to achieve the treatment. The main objective of this review is to summarize the current advances, applications, and the prevalent difficulties and opportunities to apply the CW technology for AMD treatment. According to the cited literature, sub-surface CW (SS-CW) systems are suggested for an efficient AMD treatment. The synergistic interactions between CW components determine heavy metal removal from water solution. The microorganism-plant interaction is considered the most important since it implies symbiosis mechanisms for heavy metal removal and tolerance. In addition, formation of litter and biofilm layers contributes to heavy metal removal by adsorption mechanisms. The addition of organic amendments to the substrate material and AMD bacterial consortium inoculation are some of the strategies to improve heavy metal removal. Adequate experimental design from laboratory to full scale systems need to be used to optimize equilibria between CW components selection and construction and operational costs. The principal limitations for CW treating AMD is the toxicity effect that heavy metals produce on CW plants and microorganisms. However, these aspects can be solved partially by choosing carefully constructed wetlands components suitable for the AMD characteristics. From the economic point of view, a variety of factors affects the cost of constructed wetlands, such as: detention time, treatment goals, media type, pretreatment type, number of cells, source, and availability of gravel media, and land requirements, among others.

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Bioremediation of acid mine drainage in constructed wetlands: Aspect of vegetation (Typha latifolia), loading rate and metal recovery

Minerals Engineering ◽

10.1016/j.mineng.2021.107083 ◽

2021 ◽

Vol 171 ◽

pp. 107083

Author(s):

Shweta Singh ◽

Saswati Chakraborty

Keyword(s):

Acid Mine Drainage ◽

Constructed Wetlands ◽

Loading Rate ◽

Mine Drainage ◽

Typha Latifolia ◽

Metal Recovery ◽

Acid Mine

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Recent developments in materials used for the removal of metal ions from acid mine drainage

Applied Water Science ◽

10.1007/s13201-020-01350-9 ◽

2021 ◽

Vol 11 (2) ◽

Author(s):

Tebogo M. Mokgehle ◽

Nikita T. Tavengwa

Keyword(s):

Heavy Metal ◽

Surface Water ◽

Acid Mine Drainage ◽

Metal Ions ◽

Mine Drainage ◽

Acid Mine ◽

Adsorption Capacities ◽

Ion Imprinted ◽

Wide Range ◽

Ion Imprinted Polymers

AbstractAcid mine drainage is the reaction of surface water with sub-surface water located on sulfur bearing rocks, resulting in sulfuric acid. These highly acidic conditions result in leaching of non-biodegradeable heavy metals from rock which then accumulate in flora, posing a significant environmental hazard. Hence, reliable, cost effective remediation techniques are continuously sought after by researchers. A range of materials were examined as adsorbents in the extraction of heavy metal ions from acid mine drainage (AMD). However, these materials generally have moderate to poor adsorption capacities. To address this problem, researchers have recently turned to nano-sized materials to enhance the surface area of the adsorbent when in contact with the heavy metal solution. Lately, there have been developments in studying the surface chemistry of nano-engineered materials during adsorption, which involved alterations in the physical and chemical make-up of nanomaterials. The resultant surface engineered nanomaterials have been proven to show rapid adsorption rates and remarkable adsorption capacities for removal of a wide range of heavy metal contaminants in AMD compared to the unmodified nanomaterials. A brief overview of zeolites as adsorbents and the developent of nanosorbents to modernly applied magnetic sorbents and ion imprinted polymers will be discussed. This work provides researchers with thorough insight into the adsorption mechanism and performance of nanosorbents, and finds common ground between the past, present and future of these versatile materials.

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Influence of Monovalent Cations on the Efficiency of Ferrous Ion Oxidation, Total Iron Precipitation, and Adsorptive Removal of Cr(VI) and As(III) in Simulated Acid Mine Drainage with Inoculation of Acidithiobacillus ferrooxidans

Metals ◽

10.3390/met8080596 ◽

2018 ◽

Vol 8 (8) ◽

pp. 596 ◽

Cited By ~ 2

Author(s):

Yongwei Song ◽

Heru Wang ◽

Jun Yang ◽

Yanxiao Cao

Keyword(s):

Heavy Metal ◽

Acid Mine Drainage ◽

Acidithiobacillus Ferrooxidans ◽

Mine Drainage ◽

Metal Removal ◽

Heavy Metal Removal ◽

Monovalent Cations ◽

Iron Minerals ◽

Acid Mine ◽

Removal Efficiencies

Acid mine drainage is highly acidic and contains large quantities of Fe and heavy metal elements. Thus, it is important to promote the transformation of Fe into secondary iron minerals that exhibit strong heavy-metal removal abilities. Using simulated acid mine drainage, this work analyzes the influence of monovalent cations (K+, NH4+, and Na+) on the Fe2+ oxidation and total Fe deposition efficiencies, as well as the phases of secondary iron minerals in an Acidithiobacillus ferrooxidans system. It also compares the Cr(VI) (K2Cr2O7) and As(III) (As2O3) removal efficiencies of different schwertmannites. The results indicated that high concentrations of monovalent cations (NH4+ ≥ 320 mmol/L, and Na+ ≥ 1600 mmol/L) inhibited the biological oxidation of Fe2+. Moreover, the mineralizing abilities of the three cations differed (K+ > NH4+ > Na+), with cumulative Fe deposition efficiencies of 58.7%, 28.1%, and 18.6%, respectively [n(M) = 53.3 mmol/L, cultivation time = 96 h]. Additionally, at initial Cr(VI) and As(III) concentrations of 10 and 1 mg/L, respectively, the Cr(VI) and As(III) removal efficiencies exhibited by schwertmannites acquired by the three mineralization systems differed [n(Na) = 53.3 > n(NH4) = 53.3 > n(K) = 0.8 mmol/L]. Overall, the analytical results suggested that the removal efficiency of toxic elements was mainly influenced by the apparent structure, particle size, and specific surface area of schwertmannite.

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