Heavy Metals Leaching of Active Carbon from Sewage Sludge Modified by Chitosan for Dye Wastewater Treatment

2012 ◽  
Vol 627 ◽  
pp. 399-403
Author(s):  
Xiao Dan Fan ◽  
Xiang Kai Zhang

Heavy metal leaching limits activated carbon from sewage sludge (referred as ACS) to be used for wastewater treatment. Cr and Cd leaching from ACS exceed the permitted values. The leaching content of Cr and Cd decrease much with depositing ACS with chitosan (CS),below the permitted values. This is mainly due to the bind of Cr and Cd with the much group –NH2 of CS. The effects of initial dye concentration, pH and contact time had been studied. The dye adsorbed can act as a supple complexion agent with increasing initial dye concentration, increase the affinity for Cr and Cd. For Cd, the amount leaching of CS/ACS or ACS remains content with pH.The amount leaching of Cr decreases when the pH from 1 to 5 and then increases above the pH of 6.0. The contact time has no important influence on the leaching contents of Cr or Cd.

2016 ◽  
Vol 23 (2) ◽  
pp. 271-283 ◽  
Author(s):  
Thomas Spanos ◽  
Antoaneta Ene ◽  
Chrysoula Styliani Patronidou ◽  
Christina Xatzixristou

AbstractThe aim of this study was to evaluate the temporal variations of selected heavy metals level in anaerobic fermented and dewatered sewage sludge. Sewage sludge samples were collected in different seasons and years from three municipal wastewater treatment plants (WWTPs) located in Northern Greece, in Kavala (Kavala and Palio localities) and Drama (Drama locality) Prefectures. An investigation of the potential of sludge utilization in agriculture was performed, based on the comparison of average total heavy metal concentrations and of chromium species (hexavalent, trivalent) concentrations with the allowed values according to the Council Directive 86/278/EEC and Greek national legislation (Joint Cabinet Decision 80568/4225/91) guidelines. In this regard, all the investigated heavy metals (Cd, Cr, Cu, Ni, Pb, Zn, Hg) and chromium species Cr(VI) and Cr(III) have average concentrations (dry matter weight) well below the legislated thresholds for soil application, as following: 2.12 mg kg−1Cd; 103.7 mg kg−1Cr; 136.4 mg kg−1Cu; < 0.2 mg kg−1Hg; 29.1 mg kg−1Ni; 62.0 mg kg−1Pb; 1253.2 mg kg−1Zn; 1.56 mg kg−1Cr(VI) and 115.7 mg kg−1Cr(III). Values of relative standard deviation (RSD) indicate a low or moderate temporal variability for domestic-related metals Zn (10.3-14.7%), Pb (27.9-44.5%) and Cu (33.5-34.2%), and high variability for the metals of mixed origin or predominantly resulted from commercial activities, such as Ni (42.4-50.7%), Cd (44.3-85.5%) and Cr (58.2-102.0%). For some elements the seasonal occurrence pattern is the same for Kavala and Palio sludge, as following: a) Cd and Cr: spring>summer>winter; b) Cu, Ni and Pb: winter>spring>summer. On average, in summer months (dry season) metal concentrations are lower than in spring and winter (wet seasons), with the exception of Zn. For Kavala and Palio the results demonstrate that the increased number of inhabitants (almost doubled) in summer time due to tourism does not influence the metal levels in sludge. Comparing the results obtained for similar spring-summer-winter sequences in 2007 and 2010/11 and for the spring season in 2007, 2008 and 2010, it can be noticed that, in general, the average heavy metal contents show an increasing tendency towards the last year. In all the measurement periods, the Palio sludge had the highest metal contents and Kavala sludge the lowest, leading to the conclusion that the WWTP operating process rather than population has a significant effect upon the heavy metal content of sludge. Cr(VI)/Cr(total) concentration ratios are higher for Kavala sludge in the majority of sampling campaigns, followed by Drama and Palio sludge. The metals which present moderate to strong positive correlation have common origin, which could be a domestic-commercial mixed source.


2021 ◽  
Vol 6 (2) ◽  
Author(s):  
Victor O. Fatokun ◽  
Femi K. Owofadeju ◽  
Oluseyi E. Ewemoje ◽  
Temitayo A. Ewemoje

Textile industries wastewater contains pollutants which vary greatly and depend on the chemicals and treatment processes used. Toxic heavy metals in wastewater are discharged into the environment, which adversely affect human, aquatic life, and natural water bodies. This study was therefore designed to investigate adsorption of heavy metal ions (Cadmium, Zinc, Manganese, Chromium and iron) in raw textile wastewater using activated carbon from Cordia millenii and Gmelina arborea wood species. Carbon structural pattern was examined using SEM equipment. Batch sorption tests were conducted in wastewater treatment by varying absorbent contact time with the sorbate from 30 to 120minutes (at 30minutes intervals) to facilitate attainment of equilibrium condition. The pore space diameter mean values were 9.28±1.22 and 4.45±1.57µm for Cordia millenii Carbon (CMC) and Gmelina arborea Carbon (GAC) respectively. It was observed that over 80% Manganese removal was achieved at 120minutes contact time for both carbon studied. Highest removal efficiencies was observed at all contact times in GAC for iron while in CMC for Chromium, Cadmium, Zinc and Manganese between 30-90minutes contact time. After 120 minutes contact time, there was insignificant difference in removal efficiency for Chromium and Manganese. However, at 30minutes contact time, percentage removal of over 60% was obtained for Manganese, implying that Manganese has high mobility towards the adsorbents surface. The activated carbons obtained from these two wood species are therefore viable options for heavy metal removal from textile effluents. Keywords— Adsorption, activated carbon, Cordia millenii carbon, Gmelina arborea carbon, heavy metals.


Investigation of the possibility of treating wastewater containing Cu2+ heavy metal with activated carbon material prepared from macadamia husk with activating K2CO3 in Optimal conditions such as temperature 6500C and burning time is 60 minutes. Survey results show that coal with the ability to handle heavy metals is best at 84.02% in optimal conditions such as pH=5 and time. Baking is 30 minutes. The results show similarities with other research results and are applicable to wastewater treatment Cu2+.


2016 ◽  
Vol 34 (15) ◽  
pp. 1810-1819 ◽  
Author(s):  
Qunxing Huang ◽  
Ben Yu ◽  
Kunzan Qiu ◽  
Guoshun Zhou ◽  
Shoukang Wang ◽  
...  

Author(s):  
Malwina Tytła

This study aimed to assess the pollution and potential ecological risk of seven heavy metals (Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in the sewage sludge collected from a wastewater treatment plant (WWTP), located in the most industrialized region of Poland (Silesian Voivodeship). The concentrations of heavy metals were determined using inductively coupled plasma optical spectrometry (ICP-OES) and cold vapor atomic absorption spectrometry (CVAAS). The chemical forms (chemical speciation) of heavy metals were determined using the three-step chemical sequential extraction procedure, developed by the Community Bureau of Reference (BCR). To assess the pollution level and potential ecological risk, the following indices were used: Geoaccumulation Index (Igeo), Potential Ecological Risk Factor (ER), Individual Contamination Factor (ICF), Risk Assessment Code (RAC), and Ecological Risk Factor (ERF)—the author’s index. Sludge samples were collected at successive stages of processing. The results revealed that the activated sludge process and sludge thickening have a significant impact on heavy metal distribution, while anaerobic digestion and dehydration decrease their mobility. The most dominant metals in the sludge samples were Zn and Cu. However, the content of heavy metals in sewage sludge did not exceed the permissible standards for agricultural purposes. The concentrations of heavy metals bound to the immobile fractions exhibited higher concentrations, compared to those bound to mobile fractions (except Zn). The values of the total indices indicated that sludge samples were moderately to highly contaminated with Zn, Hg, Cd, Cu, and Pb, of which only Hg, Cd, and Cu posed a potential ecological risk, while according to the speciation indices, sludge samples were moderately to very highly polluted with Zn, Cu, Cd, Cr, and Ni, of which Zn, Ni, and Cd were environmentally hazardous. The obtained results proved that assessment of the pollution level and potential ecological risk of heavy metals in sewage sludge requires knowledge on both their total concentrations and their chemical forms. Such an approach will help prevent secondary pollution of soils with heavy metals, which may influence the reduction of health risks associated with the consumption of plants characterized by a high metal content.


2007 ◽  
pp. 227-237
Author(s):  
Nataliia Suchkova ◽  
Yuri Vergeles

The contamination of the sewage sludge fields of municipal wastewater treatment plants (WWTPs) by heavy metals, hydrocarbons or other pollutants is a major environmental problem. Sludge can retain up to 96% of all the metals entering the WWTPs in sewage, therefore, when it is disposed to land, heavy metals will be accumulated in the soil. Effects of heavy metal accumulation are long lasting and even permanent. Phytotoxicity is the main problem, although metals can be transferred directly to man via vegetables and other crops or indirectly via animals, primarily cattle, eating herbage (zootoxic). The common metals in sludge are Zn, Cu, Ni, Pb, Cr, and Cd which are generally the most toxic metal found in high concentration.Conventional treatment techniques of contaminated territory suffer from serious shortcomings which limit their applicability and efficiency. These include high cost and maintenance requirements, the need to transfer the contamination from one medium to another, and the extended duration of the operation. Alternatives to these treatments lie in in­situ phytoremediation. Plants are among the most tolerant organisms to pollution, which emphasizes their utility for the detoxification or degradation of pollutants. The concept of phytoremediation was inspired by the discovery of hyper-accumulators, most of which belong to the botanical families Brassicaceae, Poaceae, Papilionaceae, Caryophyllaceae, and Asteraceae, which provide most of the candidates for heavy metal phytoremediation. Two other families are important - the Salicaceae with the genera Salix and Populus, which are effective against a range of pollutants; and the Betaceae which contribute species effective against salt ions and small (few rings) polycyclic aromatic hydrocarbons (PAHs). Some Asteraceae species have been shown to be good phytoremediants of radionuclide pollution [ I ].This paper summarizes the results obtained from laboratory, as well as from in-situ experiments (sludge fields at Kharkiv's WWTP, total area is approx. 126 ha) which focused on phytoremediation methodologies for the removal of heavy metals from sewage sludge.


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