Heavy metals distribution and their bioavailability in earthworm assistant sludge treatment wetland

Objective: This research aimed to assay the dehydration and stabilization of surplus biosolids from a wastewater activated sludge treatment plant, with sludge-treatment wetlands, at the Iguazú National Park (Misiones, Argentina). Materials and Methods: A 12-cell sludge-treatment reed beds (STRB) system was built and operated for four years. Afterwards, the accumulated sediments were analyzed for total solids (TS) concentration, volatile solids (VS) reduction, specific oxygen-uptake rate (SOUR), and heavy metals and pathogens concentrations. Results and Discussion: TS concentration increased from 0.55 % to 14.3 %, VS were reduced by 33.3 %, and SOUR lowered to 1.09 mg O2gTS-1 h-1. These figures and the final concentrations of heavy metals and pathogenic microorganisms (102 MPN E.coli.gTS-1) indicated a degree of stabilization and sanitation that allowed classifying these biosolids as Class A, according to the Argentine guidelines, National Resolution 410/18, and enabled their reuse for soil amendment in landscapes and other agronomic purposes. Conclusion: The technology tested showed good results applied under a tropical climate, with annual temperatures between 17 and 27 °C, rainfall of 1870 mm y-1, and planted with autochthonous vegetation. Furthermore, it allowed the reuse of 221 t (144 m3) of a harmless product in an environmentally sustainable way.

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The Bioaccumulation Performance of Reeds and Cattails in a Constructed Treatment Wetland for Removal of Heavy Metals in Landfill Leachate Treatment (Etueffont, France)

Water Air & Soil Pollution ◽

10.1007/s11270-011-0978-3 ◽

2011 ◽

Vol 223 (4) ◽

pp. 1723-1741 ◽

Cited By ~ 42

Author(s):

Elise Grisey ◽

Xavier Laffray ◽

Océane Contoz ◽

Eric Cavalli ◽

Jacque Mudry ◽

...

Keyword(s):

Heavy Metals ◽

Landfill Leachate ◽

Treatment Wetland ◽

Leachate Treatment ◽

Removal Of Heavy Metals ◽

Constructed Treatment Wetland

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The impact of sewage sludge treatment on the content of selected heavy metals and their fractions

Environmental Research ◽

10.1016/j.envres.2017.02.035 ◽

2017 ◽

Vol 156 ◽

pp. 19-22 ◽

Cited By ~ 35

Author(s):

Katarzyna Ignatowicz

Keyword(s):

Heavy Metals ◽

Sewage Sludge ◽

Sludge Treatment ◽

Sewage Sludge Treatment ◽

The Impact

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The Use of Sludge and Sulphide to Remove Heavy Metals from Sewages before Activated Sludge Treatment

Water Science & Technology ◽

10.2166/wst.1988.0178 ◽

1988 ◽

Vol 20 (4-5) ◽

pp. 285-292 ◽

Cited By ~ 2

Author(s):

István Licskó

Keyword(s):

Heavy Metals ◽

Activated Sludge ◽

Municipal Wastewater ◽

Settling Tank ◽

Sludge Treatment ◽

Unit Costs ◽

Sulphide Ions ◽

Costs Of Treatment ◽

Simple Phase ◽

Plant Trials

The removal of five different heavy metals (Zn2+, Cu2+, Cr 3+,Cd 2+ and Ni 2+) was studied under laboratory conditions using close to neutral mixed municipal wastewater. 90 to 95 % of the Zn2+, Cu2+ and Cr3+ was found to precipitate within 5 min and to become removable by simple phase separation. The Cd2+ and Ni2+, however, refused to precipitate, unless a “reagent” (sulphide ion, primary and activated sludge) was added. In the presence of these, cadmium was normally more readily removed than nickel. Both heavy metals were removed most efficiently, when primary sludge (1.4 g.dm−3) and sulphide ions (5-15 mg.dm−3) were added in combination. As demonstrated by plant trials, this treatment would cause the heavy metals to precipitate and settle out in the primary settling tank, so that traces only would enter the aeration tank.The excess sludge would thus contain trace quantities of heavy metals only, removing an obstacle to land disposal. The introduction of this unit operation has been estimated to increase the overall construction and costs of sewage and sludge treatment by 2.3 %, the unit costs of treatment by 6 %.

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