|
|
Chen, M., Li, L., Grace, J., Tazaki, K., Shiraki, K., Asada, R., et al. (2007). Remediation of acid rock drainage by regenerable natural clinoptilolite. Water, Air, Soil Pollut., 180(1-4), 11–27.
Abstract: Clinoptilolite is investigated as a possible regenerable sorbent for acid rock drainage based on its adsorption capacity for Zn, adsorption kinetics, effect of pH, and regeneration performance. Adsorption of Zn ions depends on the initial concentration and pH. Adsorption/Desorption of Zn reached 75% of capacity after 1-2 h. Desorption depended on pH, with an optimum range of 2.5 to 4.0. The rank of desorption effectiveness was EDTAEDTA > NaCl > NaNO3 > NaOAc > NaHCO3 > Na2CO3 > NaOH > CeCa(OH)(2). For cyclic absorption/desorption, adsorption remained satisfactory for six to nine regenerations with EDTA and NaCl, respectively. The crystallinity and morphology of clinoptilolite remained intact following 10 regeneration cycles. Clinoptilolite appears to be promising for ARD leachate treatment, with significant potential advantages relative to current treatment systems.
|
|
|
|
Murray-Gulde, C. L. (). Contributions of Schoenoplectus californicus in a constructed wetland system receiving copper contaminated wastewater. Water, Air, Soil Pollut., 163(1-4), 355–378.
Abstract: Functional roles of Schoenoplectus californicus, giant bulrush, were evaluated in an 3.2 ha (8-acre) constructed wetland treatment system receiving copper-contaminated water. The constructed wetland used in this research was designed to decrease bioavailable copper concentrations in a wastestream and eliminate associated toxicity to downstream biota by exploiting the thermodynamic processes responsible for copper speciation. This was achieved by integrating carbon, sulfur and copper biogeochemical cycles. In this system, S. californicus, which represents an integral part of the carbon cycle, provides a physical, chemical and biological role in removing metals from the aqueous phase. The specific contributions of S. californicus in this system are to provide a sustainable carbon source for removal of copper by (1) provision of an organic ligand for sorption of copper entering the system, (2) production of organic ligands through growth of S. californicus, (3) accretion of organic ligands over time due to decomposition of S. californicus detritus, and (4) use of organic carbon as an energy source for dissimilatory sulfate production. Shoots and roots of viable S. californicus sorbed 0.88% and 5.88%, respectively, of copper entering the system. The half-life of S. californicus detritus in the constructed wetland system was approximately 184 d, indicating that sufficient detritus will accrete over time, providing binding sites for copper and an energy source for bacterial metabolic processes that contribute to copper immobilization in wetland systems.
|
|
|
|
Groudev, S. N. (2002). Treatment of acid mine drainage by a natural wetland. Wetlands and Remediation Ii, , 133–139.
Abstract: Acid drainage waters generated in the copper ore deposit Elshitza. Central Bulgaria, were treated by a natural wetland located in the deposit. The waters had a pH in the range of about 2.5 – 3.5 and contained copper, cadmium, arsenic, iron, manganese and sulphates as main pollutants. The watercourse through the wetland covered a distance of about 100 in and the water flow rate varied in the range of about 0.5 – 2.0 1/s. The wetland was characterized by an abundant water and emergent vegetation and a diverse microflora. Phragmites communis was the prevalent plant species in the wetland but species of the genera Scirpus, Typha, Juncus, Carex and Poa as well as different algae were also well present. It was found that an efficient removal of the pollutants was achieved and their residual concentrations in the wetland effluents were decreased below the relevant permissible levels for water intended for use in the agriculture and/or industry. The removal was clue to different processes but the microbial dissimilatory sulphate reduction and the sorption of pollutants by the organic matter and clay minerals present in the wetland played the main role. Negative effects of the pollutants on the growth and activity of the indigenous plant and microbial communities were not observed.
|
|
|
|
Ye, Z. H. (2004). Use of a wetland system for treating Pb/Zn mine effluent: A case study in southern China from 1984 to 2002. Wetlands Ecosystems in Asia: Function and Management, 1, 413–434.
Abstract: A constructed wetland system in Guangdong Province, South of China has been used for treating Pb/Zn mine discharge since 1984. In this chapter, the performance of this system in the purification of mine discharge, metal accumulation in different ecological compartments and ecological succession within the system during the period of 1984-2002 has been reviewed. The data show that the wetland system not only effectively remove metals (mainly Pb, Zn, Cd and Cu) and total suspended solids from the mine discharge over a long period leading to significant improvement in water quality, but also gradually increase diversity and abundance of living organisms.
|
|
