Removal of Heavy Metals from Municipal Wastewater Sludge Under the Effect of Electric Current Application

Heavy metal concentration in sludge is one of the major obstacles for the application of sludge on land. There are various methods for the removal of heavy metals in sludge. Using sulfur oxidizing bacteria for microbiological removal of heavy metals from sludges is an outstanding option because of high metal solubilization rates and the low cost. In this study, bioleaching by indigenous sulfur oxidizing bacteria was applied to sludges generated from the co-treatment of municipal wastewater and leachate for the removal of selected heavy metals. Sulfur oxidizing bacteria were acclimated to activated sludge. The effect of the high organic content of leachate on the bioleaching process was investigated in four sets of sludges having different concentrations of leachate. Sludges in Sets A, B, C and D were obtained from co-treatment of wastewater and 3%, 5%, 7% and 10% (v/v) leachate respectively. The highest Cr, Ni and Fe solubilization was obtained from Set A. Sulfur oxidizing bacteria were totally inhibited in Set D that received the highest volume of leachate.

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Occurrence and Fate of Heavy Metals in Municipal Wastewater in Heilongjiang Province, China: A Monthly Reconnaissance from 2015 to 2017

Water ◽

10.3390/w12030728 ◽

2020 ◽

Vol 12 (3) ◽

pp. 728 ◽

Cited By ~ 2

Author(s):

Peng Du ◽

Lingrong Zhang ◽

Yuntao Ma ◽

Xinyue Li ◽

Zhenglu Wang ◽

...

Keyword(s):

Heavy Metals ◽

Urban Areas ◽

Municipal Wastewater ◽

Flow Analysis ◽

Material Flow Analysis ◽

Wastewater Sludge ◽

County Level ◽

Heilongjiang Province ◽

Municipal Wastewater Treatment ◽

Modeling Tools

As one of the major sources of pollutions in the environments, effluents from municipal wastewater recently became a hot topic. This study quantified monthly county-level releases of five heavy metals, i.e., lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As), and mercury (Hg), from municipal wastewater into the environment in the Heilongjiang Province of China, based on sampling, measurement, and modeling tools. Wastewater samples were collected from 27 municipal wastewater treatment plants (MWTPs) in 15 county-level cities of Heilongjiang every month from 2015 to 2017. The concentrations of five heavy metals were analyzed in both influents (Pb: 160 ± 100 μg/L; Cd: 15 ± 9.0 μg/L; Cr: 170 ± 64 μg/L; Hg: 0.67 ± 1.5 μg/L; As: 6.2 ± 4.8 μg/L) and effluents (Pb: 45 ± 15 μg/L; Cd: 5.2 ± 5.1 μg/L; Cr: 57 ± 13 μg/L; Hg: 0.28 ± 0.12 μg/L; As: 2.6 ± 1.4 μg/L). The removal ratios of the five heavy metals ranged from 50% to 67%. Inflow fluxes of Pb, Cr, and Cd displayed increasing trends first then decreased after reaching a maximum value, whereas those of Hg and Pb remained stable. Material flow analysis reveals that constructions of MWTPs are conducive to significantly reduce the releases of heavy metals from urban areas into the aquatic environment in the study area. Additionally, municipal wastewater sludge (used as fertilizer or spread on the land) could be a significant source of heavy metals in the land.

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Effects of Electric Current and Potential on the Electrokinetic Removal of Heavy Metals from an Abandoned Mine Tailings

Journal of Environmental Science International ◽

10.5322/jes.2004.13.2.149 ◽

2004 ◽

Vol 13 (2) ◽

pp. 149-159

Author(s):

Hyun-Moo Shin ◽

Chang-Eun Lee

Keyword(s):

Heavy Metals ◽

Electric Current ◽

Mine Tailings ◽

Abandoned Mine ◽

Removal Of Heavy Metals ◽

Abandoned Mine Tailings

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REDUCTION OF THE LEVEL OF TECHNOGENIC HAZARD NEGATIVE EFFECT OF SEDIMENTS OF URBAN WASTE WATER ON THE ENVIRONMENT WITH HUMIC SUBSTANCES

Technogenic and Ecological Safety ◽

10.52363/2522-1892.2021.2.11 ◽

2021 ◽

pp. 70-74

Author(s):

Stanislav Dushkin

Keyword(s):

Heavy Metals ◽

Humic Substances ◽

Municipal Wastewater ◽

Negative Impact ◽

Wastewater Sludge ◽

Ecological Problem ◽

Urban Wastewater ◽

Water Object ◽

Negative Effect ◽

Methods Of Treatment

The article discusses the issues of reducing the level of technogenic safety of the negative impact of urban wastewater sludge on the environment by removing heavy metals using humic substances. It is noted that the technogenic and ecological problem requires an urgent solution through the formation of new effective methods of treatment (neutralization and dehydration) and further disposal of urban wastewater sludge. Silt sites are a source of pollution of soil, groundwater and surface water object and air. A new method for removing heavy metals from municipal wastewater sludge using humic substances has been developed. It was found that humic substances have a sorption capacity in relation to heavy metals. As a reagent for removing heavy metals from urban wastewater sludge, it is proposed to use the product of processing lignite and peat with alkali using a carbon-alkali reagent, which makes it possible to reduce the concentration of heavy metals to such concentrations that the sludge can be used as fertilizer in agriculture.

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Heavy metals extraction from anaerobically digested sludge

Water Science & Technology ◽

10.2166/wst.2002.0275 ◽

2002 ◽

Vol 46 (10) ◽

pp. 1-8 ◽

Cited By ~ 31

Author(s):

M.M. Marchioretto ◽

H. Bruning ◽

N.T.P. Loan ◽

W.H. Rulkens

Keyword(s):

Heavy Metals ◽

Municipal Wastewater ◽

Extraction Efficiency ◽

Extraction Process ◽

Chemical Extraction ◽

Second Phase ◽

Specific Situation ◽

Ph Values ◽

Sequential Chemical Extraction ◽

Removal Of Heavy Metals

This paper reports on the chemical extraction efficiency in the removal of heavy metals from sludge from an activated-sludge system, which receives as influent both industrial and municipal wastewater. Utilizing a series of chemical extractants in a sequential order comprised the first phase of the research, called sequential chemical extraction (SCE). The work started with the well-known Tessier method followed by Veeken and by Sims and Kline SCE schemes. Afterwards, modified versions of Tessier and Veeken schemes were applied. The second phase, named chemical extraction using pH progressive changes, concerns an alternative to the extraction process. Four acids were tested: nitric, hydrochloric, oxalic and citric and the pH values as well as the time were varied. Some conclusions reveal that although modifying Tessier and Veeken schemes provides more consistent results, SCE is still an imperfect method regarding specificity and selectivity. Besides, it is not advisable to apply one SCE scheme developed for one specific situation to another one, once the accurateness of the method depends on several factors such as sort of material and chemicals, contact time, temperature, etc. The extraction efficiency increases using nitric or hydrochloric acids at low pH values, promoting high extraction efficiency level.

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Evaluation of Heavy Metals Leakage from Concretes Containing Municipal Wastewater Sludge

Environment and Pollution ◽

10.5539/ep.v1n2p176 ◽

2012 ◽

Vol 1 (2) ◽

Cited By ~ 6

Author(s):

Elham Khalilzadeh Shirazi ◽

Reza Marandi

Keyword(s):

Heavy Metals ◽

Municipal Wastewater ◽

Wastewater Sludge

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Removal of Heavy Metals during Primary Treatment of Municipal Wastewater and Possibilities of Enhanced Removal: A Review

Water ◽

10.3390/w13081121 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1121

Author(s):

Sylwan Ida ◽

Thorin Eva

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Municipal Wastewater ◽

Metal Removal ◽

Metal Speciation ◽

Heavy Metal Removal ◽

Primary Treatment ◽

Metal Concentrations ◽

Heavy Metal Concentrations ◽

Removal Of Heavy Metals

Resource reuse has become an important aspect of wastewater management. At present, use of sludge in agriculture is one of the major reuse routes. Conventional municipal wastewater treatment does not involve any designated process for removal of heavy metals, and these distribute mainly between effluent and sludge. Enhanced removal of heavy metals during primary treatment may decrease the heavy metal concentrations in both effluent and sludge from secondary treatment and promote long-term reuse of secondary sludge. This review considers heavy metal occurrence and removal during primary settling, together with possible treatment technologies for heavy metal removal in primary settlers and their theoretical performance. The variation in total heavy metal concentrations and dissolved fraction in raw municipal wastewater points to a need for site-specific assessments of appropriate technologies for improved heavy metal removal. Studies examining the heavy metal speciation beyond dissolved/particulate are few. Missing or disparate information on process parameters such as hydraulic retention time, pH and composition of return flows makes it hard to generalize the findings from studies concerning heavy metal removal in primary settlers. Coagulation/flocculation and use of low-cost sorbents were identified as the most promising methods for enhancing heavy metal removal during primary settling. Based on the available data on heavy metal speciation and removal during primary settling, sorption technologies may be most effective for enhancing the removal of Cu and Ni, while coagulation may be efficient for Cd, Cr, Cu, Pb, Zn and Hg removal (but not as efficient for Ni removal).

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Effects of Current, Electrodes Spacing and Operational Time on the Removal of Heavy Metals from Primary Treated Municipal Wastewater using Dielectrophoresis

University of the Future: Re-Imagining Research and Higher Education ◽

10.29117/quarfe.2020.0088 ◽

2020 ◽

Author(s):

Abdulkarim Ibrahim Almukdad ◽

Radwan Ahmad Firas Alfahel ◽

Alaa AlHawari

Keyword(s):

Heavy Metals ◽

Municipal Wastewater ◽

Aluminium Content ◽

Applied Current ◽

Ac Power ◽

Removal Of Heavy Metals ◽

Treated Municipal Wastewater ◽

Alternative Current ◽

Better Than ◽

Operational Time

Electrocoagulation (EC) is an emerging technology that has been used to treat heavy metals from different kinds of wastewater. This paper discusses the effects of inducing Dielectrophoretic (DEP) force in EC system for the treatment of heavy metals from primary treated municipal wastewater. In order to achieve the optimum run of DEP, COMSOL software was used to identify the highest force that can be obtained by changing electrodes spacing and applied current. As per the results obtained from experiments and numerical methods, the optimum run was at operational time of 30 min, electrodes spacing of 0.5 cm and applied current of 600 mA (17.14 mA/cm2 current density). In both process aluminium electrodes were used and they were connected to alternative current (AC) power supply. The efficiency of AC-DEP was found to be better than AC-EC. The removal efficiencies of Fe and Mn using AC-DEP were 80.6% and 29.7% respectively, while AC-EC removed 78.23% of Fe and 28.8% of Mn. Moreover, the increase in the aluminium content using AC-DEP and AC-EC was 810.3% and 1330.8% respectively. Furthermore, the energy consumption of AC-DEP was 4.9 kWh/m3 while AC-EC consumed 5kWh/m3.

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