Partitioning of heavy metals in sub-surface flow treatment wetlands receiving high-strength wastewater

2013 ◽  
Vol 68 (2) ◽  
pp. 486-493 ◽  
Author(s):  
Ewa Wojciechowska ◽  
Magdalena Gajewska

The retention of heavy metals at two pilot-scale treatment wetlands (TWs), consisting of two vertical flow beds (VSSF) followed by a horizontal flow bed (HSSF) was studied. The TWs received high-strength wastewater: reject waters from sewage sludge centrifugation (RW) and landfill leachate (LL). The concentrations of the metals Fe, Mn, Zn, Al, Pb, Cu, Cd, Co, and Ni were measured in treated wastewater, substrate of the beds and in plant material harvested from the beds (separately in above ground (ABG) parts and below ground (BG) parts). The TWs differed in metals retention. In the RW treating TW the metal removal efficiencies varied from 27% for Pb to over 97% for Fe and Al. In the LL treating system the concentrations of most metals decreased after VSSF-1 and VSSF-2 beds; however, in the outflow from the last (HSSF) bed, the concentrations of metals (apart from Al) increased again, probably due to the anaerobic conditions at the bed. A major removal pathway was sedimentation and adsorption onto soil substrate as well as precipitation and co-precipitation. In the LL treating facility the plants contained substantially higher metal concentrations in BG parts, while the upward movement of metals was restricted. In the RW treating facility the BG/ABG ratios were lower, indicating that metals were transported to shoots.

2011 ◽  
Vol 64 (8) ◽  
pp. 1597-1606 ◽  
Author(s):  
Ewa Wojciechowska ◽  
Sylvia Waara

The results of heavy metals (Fe, Mn, Zn, Ni, Cu, Cr, Pb, Cd) removal and partitioning between aqueous and solid phases at two treatment wetlands (TWs) treating municipal landfill leachates are presented. One of the TWs is a surface flow facility consisting of 10 ponds. The other TW is a newly constructed pilot-scale facility consisting of three beds with alternately vertical and horizontal sub-surface flow. The metals concentrations were analysed in leachate (both TWs) and bottom sediments (surface flow TW). Very high (90.9–99.9%) removal rates of metals were observed in a mature surface flow TW. The effectiveness of metals removal in a newly constructed pilot-scale sub-surface flow wetland were considerably lower (range 0–73%). This is attributed to young age of the TW, different hydraulic conditions (sub-surface flow system with much shorter retention time, unoxic conditions) and presence of metallic complexes with refractory organic matter.


2007 ◽  
Vol 56 (3) ◽  
pp. 193-198 ◽  
Author(s):  
E. Lesage ◽  
D.P.L. Rousseau ◽  
A. Van de Moortel ◽  
F.M.G. Tack ◽  
N. De Pauw ◽  
...  

The removal of Co, Ni, Cu and Zn from synthetic industrial wastewater was studied in subsurface flow constructed wetland microcosms filled with gravel or a gravel/straw mixture. Half of the microcosms were planted with Phragmites australis and half were left unplanted. All microcosms received low-strength wastewater (1 mg L−1 of Co, Ni, and Zn, 0.5 mg L−1 Cu, 2,000 mg L−1 SO4) during seven 14-day incubation batches. The pore water was regularly monitored at two depths for heavy metals, sulphate, organic carbon and redox potential. Sorption properties of gravel and straw were assessed in a separate experiment. A second series of seven incubation batches with high-strength wastewater (10 mg L−1 of each metal, 2,000 mg L−1 SO4) was then applied to saturate the substrate. Glucose was added to the gravel microcosms together with the high-strength wastewater. Sorption processes were responsible for metal removal during start-up, with the highest removal efficiencies in the gravel microcosms. The lower initial efficiencies in the gravel/straw microcosms were presumably caused by the decomposition of straw. However, after establishment of anaerobic conditions (Eh∼−200 mV), precipitation as metal sulphides provided an additional removal pathway in the gravel/straw microcosms. The addition of glucose to gravel microcosms enhanced sulphate reduction and metal removal, although Phragmites australis negatively affected these processes in the top-layer of all microcosms.


1991 ◽  
Vol 23 (1-3) ◽  
pp. 301-308 ◽  
Author(s):  
R. M. Izatt ◽  
R. L. Bruening ◽  
M. B. Borup

Aza macrocycles bound to silica gel beads were found to selectively remove heavy metal cations such as Pb2+, Cd2+, Ag+, and Hg2+ from aqueous solutions. These bound macrocycles have a virtually infinite selectivity of binding with heavy metals over alkali and alkaline earth cations. The material is very stable and can be reused hundreds of times. Columns may be regenerated using an acidic eluent solution. Equilibrium constants were determined by column tests. Removal of heavy metals was demonstrated in bench scale tests using a synthetic contaminated water and in pilot scale tests using a naturally contaminated river water. Heavy metal concentrations could be effectively reduced to the µg/L level using the process.


2017 ◽  
Vol 29 (1) ◽  
pp. 20
Author(s):  
Dragana Radovanović ◽  
Milisav Ranitović ◽  
Željko Kamberović ◽  
Marija Korać ◽  
Milorad Gavrilovski

RTB Bor smelter and sulfuric acid plant modernization project includes reconstruction of an old wastewater treatment plant (WWTP). The task for a team from the Innovation Center of TMF was technical-technological solution for the reconstruction of WWTP with a new wastewater treatment process. Wastewater from the primary copper smelter is very acidic, with a high content of dissolved heavy metals and arsenic. Treatment of wastewater includes the neutralization of the acid, precipitation of the heavy metals in the form of hydroxides by using hydrated lime, and the arsenic co-precipitation with iron(III) hydroxide. Material and energy balances of the process are determined by simulating the wastewater treatment in Superpro Designer software package with thermodynamic parameters defined in HSC Chemistry program. The simulation results were confirmed by experimental tests at the pilot plant level. The designed process is applied in WWTP exploitation within the new copper smelter RTB Bor. Treatment of 8,7 m2/h of wastewater generates 7,2 m2/h of treated wastewater and 10,3 t/h of wastewater treatment (WWT) sludge. The WWT sludge is characterized as hazardous waste requiring treatment prior to disposal. A proposed treatment for WWT sludge is solidification/stabilization (S/S) using a mixture of fly ash and hydrated lime. Results of laboratory scale tests, which included standard leaching tests EN 12457 and TCLP, as well as the compressive strength testing of obtained solidificates, shows that the S/S treatment leads to stabilization of more than 99% of the heavy metals and more than 90% of arsenic. The treated sludge has the characteristics of non-hazardous waste and is suitable for disposal.


2017 ◽  
Vol 1 (1) ◽  
pp. 46-55 ◽  
Author(s):  
Athar Hussain ◽  
Manjeeta Priyadarshi ◽  
Saif Said ◽  
Suraj Negi

Most of the industrial sewage effluents used for irrigation contains heavy metals which cause toxicity to crop plants as the soils are able to accumulate heavy metal for many years. The vegetables grown for the present study were irrigated with treated wastewater brought from a nearby full-scale sewage treatment plant at different compositions along with tap water as a control. The concentration levels of the Cd, Co, Cu, Mn and Zn in the soil were found to below the toxic limits as prescribed in literature. Daily Intake Metals (DIM) values suggest that the consumption of plants grown in treated wastewater and tap water is nearly free of risks, as the dietary intake limits of Cu, Fe, Zn and Mn. The Enrichment Factor for the treated wastewater irrigated soil was found in order Zn> Ni> Pb> Cr> Cu> Co> Mn> Cd. Thus, treated wastewater can be effectively used for irrigation. This will have twofold significant environmental advantages: (1) helpful to reduce the groundwater usage for irrigation and (2) helpful to reduce the stress on surface water resources.


2003 ◽  
Vol 3 (4) ◽  
pp. 145-152 ◽  
Author(s):  
H. Heinonen-Tanski ◽  
P. Juntunen ◽  
R. Rajala ◽  
E. Haume ◽  
A. Niemelä

Municipal treated wastewater has been tertiary treated in a pilot-scale rapid sand filter. The filtration process was improved by using polyaluminium coagulants. The sand-filtered water was further treated with one or two UV reactors. The quality changes of wastewater were measured with transmittance, total phosphorus, soluble phosphorus, and somatic coliphages, FRNA-coliphages, FC, enterococci and fecal clostridia. Sand filtration alone without coagulants improved slightly some physico-chemical parameters and it had almost no effect on content of microorganisms. If coagulants were used, the filtration was more effective. The reductions were 88-98% for microbial groups and 80% for total phosphorus. The wastewater would meet the requirements for bathing waters (2,000 FC/100 ml, EU, 1976). UV further improved the hygiene level; this type of treated wastewater could be used for unrestricted irrigation (2.2 TC/100 ml, US.EPA 1992). The improvement was better if coagulants were used. The price for tertiary treatment (filtration + UV) would have been 0.036 Euro/m3 according to prices in 2001 in 22 Mm3/a. The investment cost needed for the filtration unit was 0.020 Euro/m3 (6%/15a). Filtration with coagulants is recommended in spite of its costs, since the low transmittance of unfiltered wastewater impairs the efficiency of the UV treatment.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Waheed Ali Khoso ◽  
Noor Haleem ◽  
Muhammad Anwar Baig ◽  
Yousuf Jamal

AbstractThe heavy metals, such as Cr(VI), Pb(II) and Cd(II), in aqueous solutions are toxic even at trace levels and have caused adverse health impacts on human beings. Hence the removal of these heavy metals from the aqueous environment is important to protect biodiversity, hydrosphere ecosystems, and human beings. In this study, magnetic Nickel-Ferrite Nanoparticles (NFNs) were synthesized by co-precipitation method and characterized using X-Ray Diffraction (XRD), Energy Dispersive Spectroscopy (EDS) and Field Emission Scanning Electronic Microscopy (FE-SEM) techniques in order to confirm the crystalline structure, composition and morphology of the NFN’s, these were then used as adsorbent for the removal of Cr(VI), Pb(II) and Cd(II) from wastewater. The adsorption parameters under study were pH, dose and contact time. The values for optimum removal through batch-adsorption were investigated at different parameters (pH 3–7, dose: 10, 20, 30, 40 and 50 mg and contact time: 30, 60, 90, and 120 min). Removal efficiencies of Cr(VI), Pb(II) and Cd(II) were obtained 89%, 79% and 87% respectively under optimal conditions. It was found that the kinetics followed the pseudo second order model for the removal of heavy metals using Nickel ferrite nanoparticles.


2012 ◽  
Vol 610-613 ◽  
pp. 3252-3256
Author(s):  
Mei Qin Chen ◽  
Feng Ji Wu

Acid mine drainage (AMD) has properties of extreme acidification, quantities of sulfate and elevated levels of soluble heavy metals. It was a widespread environmental problem that caused adverse effects to the qualities of ground water and surface water. In the past decades, most of investigations were focused on the heavy metals as their toxicities for human and animals. As another main constitution of AMD, sulfate ion is nontoxic, yet high concentration of sulfate ion can cause many problems such as soil acidification, metal corrosion and health problems. More attention should be paid on the sulfate ion when people focus on the AMD. In the paper, sulfate removal mechanisms include adsorption, precipitation, co-precipitation and biological reduction were analyzed and summarized. Meanwhile, the remediation technologies, especially the applications of them in China were also presented and discussed.


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