Publication Details |
| Category | Text Publication |
| Reference Category | Journals |
| DOI | 10.1016/j.ecoleng.2014.03.050 |
| Title (Primary) | Removal and fate of arsenic in the rhizosphere of Juncus effusus treating artificial wastewater in laboratory-scale constructed wetlands |
| Author | Rahman, K.Z.; Wiessner, A.; Kuschk, P.; van Afferden, M.; Mattusch, J.; Müller, R.A.
|
| Source Titel | Ecological Engineering |
| Year | 2014 |
| Department | UBT; ANA; UBZ |
| Volume | 69 |
| Page From | 93 |
| Page To | 105 |
| Language | englisch |
| Keywords | Arsenic removal; Artificial wastewater; Constructed wetland; Juncus effusus; Mass balance; Rhizosphere |
| UFZ wide themes | RU3; |
| Abstract | The deposition, fate and distribution of arsenic (As) under dynamic redox conditions within the rhizosphere of helophytes in treatment wetlands are still poorly understood. For this purpose, long-term experiments were carried out in specially designed laboratory-scale constructed wetland reactors treating artificial domestic wastewater containing As (200 μg As l−1) in order to investigate the key aspects of As immobilization, to identify the main As removal pathway by using a mass balance approach and to assess the role of different sulfate (SO42−) concentrations on As mass retention. The results with a highly efficient As mass retention (>92%) indicated a better performance under C-deficient and oxidized conditions (Eh ∼324–795 mV) regardless to the SO42− concentration in the inflow wastewater. An elevated SO42− concentration (25 mg S l−1 in the inflow) facilitated high As-retention (>90%) under C-surplus and microbial dissimilatory SO42− reducing condition (Eh ∼−225–−149 mV) within the root-near environment of the rhizosphere in constructed wetlands. Mean pH in a range of 6.6–7.7 might be favoring the immobilization of As but a comparatively low pH (3.9–5.9) within the root vicinity might enhance plant uptake. In general, higher As concentrations were exhibited by the plant roots (90–315 mg As kg−1 dry wt) as compared to the shoots (3.5–3.8 mg As kg−1 dry wt). Nearly 3.5-fold higher As concentrations within the roots from the experimental reactor as compared to the roots collected from control reactor clearly indicated that a higher amount of As was retained, accumulated, adsorbed, metabolized to other forms on root surface and/or translocated into the roots of Juncus effusus, where organic C and SO42− were abundant. Based on As mass balance calculation, the reactor with the highest SO42− loading was found to be retained nearly 85% of the total As mass input. Out of which only <1% of the total inflow As mass was sequestered or translocated into the plant shoots, 42.2% was accumulated/recovered within the plant roots, 17.2% was entrapped or deposited within the sediments of the gravel bed, 16.2% was recovered in the pore water and 15.3% was flushed out as outflow. The remaining 9% was considered as unaccountable, which might be released due to volatilizations or lost due to various unknown reasons. A 5-fold higher SO42− concentration within the reactor might facilitate lower pH (3.9–5.9) and consequent remobilization caused a higher amount of free or exchangeable As in the pore water (16.2%), that probably resulted in a higher As uptake (42.2%) by the plant roots as compared to the roots from the control reactor (only 13%). The findings demonstrate the deposition and fate of As within the rhizosphere, which are of high importance for an efficient treatment of wastewater containing As under constructed wetland conditions. |
| Persistent UFZ Identifier | https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=14793 |
| Rahman, K.Z., Wiessner, A., Kuschk, P., van Afferden, M., Mattusch, J., Müller, R.A. (2014): Removal and fate of arsenic in the rhizosphere of Juncus effusus treating artificial wastewater in laboratory-scale constructed wetlands Ecol. Eng. 69 , 93 - 105 10.1016/j.ecoleng.2014.03.050 |
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