Importance of algae and bacteria in the bioremediation of heavy metals from wastewater treatment plants

Author(s):  
Sabeela Beevi Ummalyma ◽  
Anamika Singh
Chemosphere ◽  
2007 ◽  
Vol 66 (2) ◽  
pp. 353-361 ◽  
Author(s):  
Jiayin Dai ◽  
Muqi Xu ◽  
Jiping Chen ◽  
Xiangping Yang ◽  
Zhenshan Ke

2018 ◽  
Vol 24 (1) ◽  
Author(s):  
CRISTIAN CIOBANU ◽  
GHEORGHE VOICU ◽  
MAGDALENA – LAURA TOMA ◽  
PAULA TUDOR

<p>With the dust arising from the clinker kilns and grill coolers (the major pollution sources in a cement plant), also heavy metals and their compounds (in the form of powders and vaporous), originating from fuels and raw materials, are pumped into the air. The paper presents some aspects regarding the monitoring of heavy metals contained in the combustion gases from a Romanian cement factory. The fuels used in the incinerator varied from coal/petroleum coke, refuse oils (from waste oils and their emulsions, up to sludge, paraffin, tars, contaminated soil), rubber (including whole used tires), plastic, paper, leather, textiles, wood (including sawdust), as such or impregnated/contaminated with various substances from industrial sources or sorted household wastes, sludge (previously dried) from wastewater treatment plants. In addition, the list of over 100 types of waste that can be co-processed can be found in integrated authorizations of cement plants. However, the level of heavy metals in the combustion gases was in allowed limits.</p>


Author(s):  
Daniela CIUPEANU CĂLUGĂRU

For turning to a high degree of favorability of sludge from wastewater treatment plants, currently the reintroduction in the natural circuit of this waste is an urgent priority. Knowing precisely the composition of chemical and biological sludge from waste water in accordance with the law and the rules of their application, along with modern wastewater treatment appropriate technologies play a key role on environmental protection. Involvement by precise rules, the content of heavy metals in relation to the maximum permitted by law, translate in to particularly advantageous results in terms of environmental quality.


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.


Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1248 ◽  
Author(s):  
Yuhua Zhou ◽  
Jing Lei ◽  
Yu Zhang ◽  
Jing Zhu ◽  
Yanna Lu ◽  
...  

Industrial wastewater and sewage are both important sources of heavy metals and metalloids in urban wastewater treatment plants (WWTPs). China has made great efforts to control heavy metal and metalloid pollution by setting discharge limits for WWTPs. There is, however, limited discharge data and no systematic methodology for the derivation of discharge limits. In this study, 14 heavy metals and metalloids (Hg, alkyl mercury, As, Cd, Cr, Cr6+, Pb, Ni, Be, Ag, Cu, Zn, Mn, Se) that are listed in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002) were selected for the analysis of discharge characteristics while using the supervised monitoring data from more than 800 WWTPs located in nine provinces in China. Of the 14 heavy metals and metalloids, all but alkyl mercury were detected in the discharge water. There was a high rate of detection of As, Cu, Mn, Se, and there were some samples that exceeded the standard concentrations of Cr, Cr6+, Pb, and Ni. Removal rates of Hg, As, Cd, Cr, Cr6+, Pb, Ni, Cu, Zn, Mn, and Se were higher than 40%, comparable to values from other countries. Hg and As were selected to analyze the influencing factors of effluent and derive discharge limits of WWTPs using a statistical method, because these two metals had more detected data than other metals. The study used supervised monitoring data from Zhejiang WWTPs with 99 for Hg and 112 for As. Based on the delta-lognormal distribution, the results showed that geographic location was significantly closely correlated with Hg (P = 0.027 < 0.05) and As (P ≈ 0 < 0.05) discharge concentrations, while size (for Hg P = 0.695 > 0.05, for As P = 0.088 > 0.05) and influent concentration (R2 < 0.5) were not. Derived Hg and As discharge limits suggest that it is necessary to establish stricter discharge limits for WWTPs, which is more consistent with the real-world situation in China. The study here comprehensively researches the discharge characteristics of heavy metals and metalloids in effluent of WWTPs in China, and developed for the first time in China heavy metals and metalloids discharge limits based on statistical methods. The results may inform special discharge limit settings for WWTPs in China.


2008 ◽  
Vol 57 (9) ◽  
pp. 1329-1336 ◽  
Author(s):  
G. Carletti ◽  
F. Fatone ◽  
D. Bolzonella ◽  
F. Cecchi

This paper deals with a detailed study on the occurrence and fate of heavy metals (plus As, Fe and Al) in five Italian large wastewater treatment plants treating municipal and industrial wastewaters. The study showed that some of the compounds (As, Hg and Cd) were present at trace levels, while others were dispersed in a broad range of concentrations and were sometimes under the detection limit. The occurrence followed the order Hg = As &lt; Hg &lt; Pb &lt; Ni &lt; Cu &lt; Cr &lt; Fe &lt; Zn &lt; Al. Metals were mainly present bound to particulate organic matter in municipal wastewaters while they were often present in soluble phase in industrial wastewaters. Some heavy metals, like Hg and Pb, showed clear correlations with Al and Fe, therefore the last could be used as control parameters. Metals were removed with good efficiency in the treatment works, with the order As &lt; Cd = Cr = Zn &lt; Pb &lt; Hg &lt; Ni = Al &lt; Cu &lt; Fe. Metals then concentrated in waste activated sludge and accumulated after sludge stabilisation because of volatile solids degradation, therefore some problems may arise with limit for agricultural application, in particular for Hg, Cd and Ni.


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