scholarly journals Effects of Solid Content and Substrate Concentration on Bioleaching of Heavy Metals from Sewage Sludge Using Aspergillus niger

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 994 ◽  
Author(s):  
Shen-Yi Chen ◽  
Sheng-Ying Wang
Keyword(s):  
Heavy Metals ◽  
Aspergillus Niger ◽  
Sewage Sludge ◽  
Metal Removal ◽  
Sucrose Concentration ◽  
Land Application ◽  
Solid Content ◽  
Maximum Efficiency ◽  
Metal Leaching ◽  
Treated Sewage

The presence of heavy metals in sewage sludge not only affects the performance of sludge anaerobic digestion process but also restricts the land application of treated sewage sludge. Therefore, a fungi-mediated bioleaching process for simultaneous metal leaching and sludge digestion by Aspergillus niger was developed to treat the sewage sludge containing heavy metals in this study. The effects of two important parameters, sludge solid content and substrate (sucrose) concentration, on the performance of fungal bioleaching were investigated in this study. The results showed that the rate of pH reduction increased with increasing sludge solid contents and sucrose concentrations. In this study, the efficiency of metal removal decreases in the order of Mn > Zn > Ni > Pb. The efficiencies of metal leaching and solid degradation (SS and VSS) were found to be decreased with an increase of sludge solid content and a decrease of sucrose concentration. At 2 days of reaction time, the maximum efficiency of metal solubilization was 95, 56, 21 and 13% for Mn, Zn, Ni and Pb, respectively.

Processing dewatered sewage sludge using electrokinetic technology

2004 ◽  
Vol 50 (9) ◽  
pp. 205-211 ◽  
Author(s):  
J.Y. Wang ◽  
D.S. Zhang ◽  
O. Stabnikova ◽  
J.H. Tay
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Heterotrophic Bacteria ◽  
Land Application ◽  
Fecal Coliforms ◽  
Treated Sewage ◽  
Carbon Dioxide Evolution Rate ◽  
Removal Of Heavy Metals ◽  
Minor Losses ◽  
Dewatered Sewage Sludge

High content of heavy metals and presence of pathogens in the dewatered sewage sludge have been the main obstacles for land application of sewage sludge-made fertilizer. The aim of this study was to xamine the effects of the innovative electrokinetic (EK) technology on removal of heavy metals from sewage sludge, on the reduction of pathogens, and on sludge chemical characteristics. The results showed that the removal efficiencies for Zn, Cu, Ni, Cr, As and Pb were 94.9%, 95.4%, 89.7%, 67.8%, 31.2% and 18.7%, respectively. Acidification pretreatment of the dewatered sludge for 29 h decreased the content of heterotrophic bacteria from 1.5 × 108 c.f.u./g of wet sludge to 1.1 × 104 c.f.u./g of wet sludge. Although the initial content of total coliforms and fecal coliforms in sewage sludge were 5.8 × 105 c.f.u./g of wet sludge and 4.0 × 105 c.f.u./g of wet sludge, respectively, no viable cells were detected. Minor losses of K and N were detected, but the loss of P was found to be significant in EK treated sewage sludge. The treated sludge has technically considered as very stable based on the carbon dioxide evolution rate.

scholarly journals The Impact of Changing Environmental Conditions on the Retention of Heavy Metals Adsorbed by Pine Bark

2017 ◽  
pp. 278-284
Author(s):  
Oleksandr Khokhotva
Keyword(s):  
Heavy Metals ◽  
Environmental Conditions ◽  
Metal Removal ◽  
High Capacity ◽  
Pine Bark ◽  
Urea Solution ◽  
Metal Leaching ◽  
Total Efficiency ◽  
Runoff Water ◽  
The Impact

Landfills are widely used for the disposal of households' and industrial waste. Liquid landfill effluents contain heavy metals, are toxic to humans and ecosystems and have to be efficiently treated. One treatment option that is becoming popular is the reactive filter technology. The total efficiency of metal removal by a filter media greatly depends not only on adsorption itself, but also on the metal leaching from the adsorbent. The last parameter, in turn, may be dependant on changing environmental conditions since filters are usually located on open air and flow of contaminated water (landfill leachate, runoff water) has the intermittent nature. A filter material may dry, become frozen or stay wet, depending on a season. Previously adsorbed metals can leach from an adsorbent at the next flash of water, coming to water treatment facilities. Among others, pine bark has shown a high capacity to adsorb heavy metals from landfill leachates. In this study, pine bark has been pre-treated with urea-solution in order to increase its stability and adsorption properties. Within leaching experiments using either non-treated or pre-treated bark samples no significant influence of the changing environmental conditions on the extent of metal leaching was observed, though in most cases, metal leaching from wet bark samples exposed to freezing was somewhat higher. Zn leaching was the highest and Cu leaching the lowest for both NTB and UTB samples. The metal leaching from non-treated bark was several-fold higher compared to urea-treated bark. Possible mechanisms of barkurea interactions and reasons for enhanced metals adsorption by urea-modified bark are discussed.

Effects of Land Application of Municipal Sewage Sludge on Growth, Physiology and Accumulation of Heavy Metals in Wheat (Triticum aestivum L.)

2014 ◽  
Vol 878 ◽  
pp. 647-656 ◽  
Author(s):  
Liang Dai ◽  
Biao Lin Peng ◽  
Bi Gui Wei ◽  
Gui Ma
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Dry Weight ◽  
Land Application ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Technical Solution ◽  
Good Growth ◽  
Growth Physiology ◽  
Sludge Application

The application of sewage sludge on agricultural soils is a promising technical solution. Pot experiments were performed to study the effect of sewage sludge application on growth, physiology and accumulation of heavy metals in three kinds of wheat. The experimental results showed soil pH decreased significantly with the increase of the application of sewage sludge. The contents of Cu, Zn and Pb in the mixed soil did not exceed the Environmental quality standards for soils in China for Grade II (GB-1518-1995).Wheat obtained good growth activities after the application of sewage sludge, however, high land application of sewage sludge (the ratio of sludge in the mixed soil of dry weight was 20% and 25%) inhibited seed emergence and root length. The content of total chlorophyll in wheat increased with the increase of sewage sludge application first and reached a maximum, and then decreased with a further increase of sewage sludge. Compared with the control, the a/b value in chlorophyll showed trace change. The content of proline in wheat increased with the increase of sewage sludge in low doses of sewage sludge (5%, 10% and 15%), while there was no significant increase in the content in high land application of sewage sludge. The physiological metabolism of wheat will exhibit abnormality as the stress of pollutants from sludge exceeded the tolerance of wheat. The content of three kinds of heavy metals in wheat grain increased obviously with sludge application increasing, indicating an increasing trend, and had the phenomenon of exceeded the safety qualification of non-environmental pollution food in china at high doses of sewage sludge. Taking account of the effects of sewage sludge application on growth,physiology and accumulation of heavy metals in wheat, the doses of sludge in the mixed soil of dry weight should be lower than 15%.

scholarly journals Land Application of Treated Sewage Sludge: Community Health and Environmental Justice

2013 ◽  
Vol 121 (5) ◽  
pp. 537-542 ◽  
Author(s):  
Amy Lowman ◽  
Mary Anne McDonald ◽  
Steve Wing ◽  
Naeema Muhammad
Keyword(s):  
Sewage Sludge ◽  
Environmental Justice ◽  
Community Health ◽  
Land Application ◽  
Treated Sewage

scholarly journals Using bioleaching to remove metals from sewage sludge intended for land application

2021 ◽  
Author(s):  
Jun Nie
Keyword(s):  
Heavy Metal ◽  
Sewage Sludge ◽  
Removal Efficiency ◽  
Agricultural Land ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Treatment Plant ◽  
Land Application ◽  
Sulphur Compounds ◽  
Recommended Level

Removal of heavy metal contaminants from sewage sludge is a necessity before it is used as an agricultural fertilizer (biosolid), due to environmental concerns and municipal, provincial and federal regulations. The bioleaching method is recommended as an economical and effective process for the removal of heavy metals from the Ashbridges Bay Treatment Plant (ABTP) sludge, some of them with concentrations exceeding the recommended level by the Ontario Ministry of Agriculture, Food, and Rural Affairs guidelines. The Gram-negative thiobacilli is a group of organisms with physiological and morphological similarity and grows by oxidizing ferrous ion and reduced sulphur compounds. One species of thiobacillus, T. ferrooxidan , was recommended as an effective bacterium for the heavy metal removal from sewage sludge. This research involved the incubation of adapted sludge using fresh raw digested sludge and activated sludge of ABTP. Using adapted sludge for the bioleaching process, the method was tested in a continuously stirred tank reactor (CSTR) in combination with a series of jar tests. Results showed that the metal removal efficiency increases with decreasing pH, and the solids content does not affect the removal efficiency of cupper and zinc very much during short term jar test. The results from the long-term (20-day) CSTR test demonstrated that the high T ferrooxians-contained adapted sludge could remove copper from the sewage sludge of ABTP very effectively, by as much as 79.2%. In comparison, the simultaneous removal efficiency of zinc and cadmium were also studied for the same process and, they are 82.0% and 83.9% respectively. The TSS degradation constant rate during the 20 days' bioleaching was found to be 0.0522 day -1. It is concluded that Ontario should continue to apply sludge to agricultural land, as sludge is an economic alternative, promotes recycling of resources, and is a valuable fertilizer. However, the toxic metals in sludge should be removed from sewage sludge using the bioleaching process to recommended level before it is disposed as a fertilizer for land application.

scholarly journals Bioremoval of Different Heavy Metals in Industrial Effluent by the Resistant Fungal Strain Aspergillus niger

2021 ◽  
Vol 20 (4) ◽  
Author(s):  
K. J. Naveen Kumar ◽  
J. Prakash
Keyword(s):  
Heavy Metals ◽  
Aspergillus Niger ◽  
Metal Binding ◽  
Metal Removal ◽  
Low Cost ◽  
Heavy Metal Removal ◽  
Industrial Effluent ◽  
Toxic Metal ◽  
Differential Pulse ◽  
Toxic Heavy Metals

Developing countries are increasingly concerned with pollution due to toxic heavy metals in the environment. Unlike most organic pollutants which can be destroyed, toxic metal ions released into the environment often persist indefinitely circulating and eventually accumulating throughout the food chain thus posing a serious threat to mankind. The use of biological materials for heavy metal removal or recovery has gained importance in recent years due to their good performance and low cost. Among the various sources, both live and inactivated biomass of organisms exhibits interesting metal binding capacities. Their complex cell walls contain high content of functional groups like amino, amide, hydroxyl, carboxyl, and phosphate which have been implicated in metals binding. In the present study, Aspergillus niger was used to analyze the metal uptake from an aqueous solution. The determination of Cu+2, Pb+2, Cd+2, Zn+2, Co-2 and Ni+2 in samples was carried out by differential Pulse Anodic Voltammetry (DPASV) and the Voltammograms. Production of oxalic acid was carried out by submerged fermentation. The organism used in the present study has the ideal properties to sequester toxic metals and grow faster.

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