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

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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Impact of sludge and wastewater on Lactuca sativa L. growth and on soil pollution

Global NEST Journal ◽

10.30955/gnj.001409 ◽

2015 ◽

Vol 17 (1) ◽

pp. 148-161

Keyword(s):

Heavy Metals ◽

Soil Pollution ◽

Plant Height ◽

Lactuca Sativa ◽

Dry Matter ◽

Municipal Wastewater ◽

Pollution Load Index ◽

Dry Matter Yield ◽

Pollution Load ◽

Treated Municipal Wastewater

<div> <p>Two greenhouse pot experiments were conducted in Agrinion, Greece. The impact of treated municipal wastewater (TMWW) and sludge (i) on the growth of <em>Lactuca sativa</em> L. var Longifolia (lettuce) and (ii) on the extent of soil pollution with heavy metals was studied. Soil pollution was assessed by calculating the Pollution Load Index (PLI). Both of these experiments were conducted, using a randomized block design in four replications and seven treatments, respectively, as follows: (a) Experiment A: study of the effect of treated municipal wastewater (TMWW): [Control, 20%, 40%, 60%, 80%, 100%, (100%+30 t/ha Sludge)] and (b) Experiment B: Study of the effect of sludge (t/ha): 0,  6, 12,  18, 24 , 30, (30+100%TMWW). The sludge affected significantly plant height and fresh and dry matter yield, as well as the dry matter N content of plants, while the TMWW affected significantly the dry matter yield and non-significantly the plant height. The pollution load index (PLI) was non-significant for both treatments (sludge and TMWW). According to PLI calibration scale, the soil was found to be slightly polluted with heavy metals under both treatments.</p> </div> <p> </p>

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Heavy metal removal from wastewater and leachate co-treatment sludge by sulfur oxidizing bacteria

Water Science & Technology ◽

10.2166/wst.2001.0579 ◽

2001 ◽

Vol 44 (10) ◽

pp. 53-58 ◽

Cited By ~ 7

Author(s):

L. C. Aralp ◽

A. Erdincler ◽

T. T. Onay

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Municipal Wastewater ◽

Metal Removal ◽

Heavy Metal Removal ◽

Heavy Metal Concentration ◽

Organic Content ◽

Removal Of Heavy Metals ◽

Sulfur Oxidizing ◽

Sulfur Oxidizing Bacteria

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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Growth and accumulation of heavy metals in turnip (Brassica rapa) irrigated with different concentrations of treated municipal wastewater

Hydrology Research ◽

10.2166/nh.2014.140 ◽

2014 ◽

Vol 46 (1) ◽

pp. 60-71 ◽

Cited By ~ 7

Author(s):

Tabassum Parveen ◽

Athar Hussain ◽

M. Someshwar Rao

Keyword(s):

Heavy Metals ◽

Dry Matter ◽

Municipal Wastewater ◽

Tap Water ◽

Daily Intake ◽

Maximum Accumulation ◽

Heavy Metals Accumulation ◽

Normal Water ◽

Metals Accumulation ◽

Treated Municipal Wastewater

The present study has been carried out by irrigating turnip plants with different concentrations of treated municipal wastewater in order to see the effect on heavy metals accumulation and growth of plants. The turnip plants were watered with normal water and the results compared with results obtained by using treated municipal wastewater. The treatments used were: control (tap water) with 0, 25, 50 and 75% wastewater, and 100% wastewater, in three replications. The results indicated a substantial build-up of heavy metals in turnip irrigated with wastewater. The heavy metals content in the dry matter of the plants increased significantly with increase in wastewater concentration. Analysis of plant samples indicated the maximum accumulation of Fe (1,835 mg/kg in roots and 1,247 mg/kg in leaves) followed by Mn, Zn, Ni, Cu and Cd. The findings of this study regarding daily intake of metals suggest that the consumption of plants grown in wastewater is high, compared to consumption of those grown in tap water, but is nearly free of risks.

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Bioleaching of heavy metals from contaminated aquatic sediments using indigenous sulfur-oxidizing bacteria: a feasibility study

Water Science & Technology ◽

10.2166/wst.1998.0776 ◽

1998 ◽

Vol 37 (6-7) ◽

pp. 387-394 ◽

Cited By ~ 16

Author(s):

H. Seidel ◽

J. Ondruschka ◽

P. Morgenstern ◽

U. Stottmeister

Keyword(s):

Heavy Metals ◽

Pilot Plant ◽

River Sediments ◽

Chemical Properties ◽

Leaching Potential ◽

Removal Of Heavy Metals ◽

Sulfur Oxidizing ◽

Physical And Chemical ◽

Better Than ◽

Sulfur Oxidizing Bacteria

The removal of heavy metals from contaminated river sediments was studied using suspension leaching under laboratory conditions and percolation leaching in a pilot plant. The leaching potential of indigenous sulfur-oxidizing bacteria was compared with acid treatment. Bioleaching with elemental sulfur as substrate was found to be better than treatment with sulfuric acid for the solubilization of all metals tested. The physical and chemical properties of the sediments used in this study did not affect leaching capacity under optimum conditions in the laboratory. Under the practical conditions in the pilot plant, the redox state of sludge had a considerable influence on leaching efficiency. In a deposited oxic sediment with good permeability, about 62% of the metals tested were removed by percolation leaching after 120 days. Zn, Cd, Ni, Co and Mn were sufficiently leached to enable treated sediments to be reused as soil. In a freshly dredged anoxic sediment, only a total of 9 % of metals were removed. The results indicate that freshly dredged sediments need to undergo pretreatment before percolation leaching to improve mass transfer and to activate the leaching active bacteria.

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Bottom-to-top continuous irrigation of treated municipal wastewater for effective nitrogen removal and high quality rice for animal feeding

Water Science & Technology Water Supply ◽

10.2166/ws.2017.190 ◽

2017 ◽

Vol 18 (4) ◽

pp. 1183-1195 ◽

Cited By ~ 3

Author(s):

Dong Duy Pham ◽

Sumiko Kurashima ◽

Nobuo Kaku ◽

Atsushi Sasaki ◽

Jian Pu ◽

...

Keyword(s):

Heavy Metals ◽

Nitrogen Removal ◽

Municipal Wastewater ◽

Animal Feed ◽

Brown Rice ◽

Dry Mass ◽

Continuous Irrigation ◽

Animal Feeding ◽

Treated Municipal Wastewater ◽

Bottom To Top

Abstract A bench-scale experiment to cultivate rice for animal feeding with continuous irrigation of treated municipal wastewater (TWW) in six different conditions was carried out to examine nitrogen removal from TWW, yield and quality of harvested rice, and accumulation of heavy metals in soil and rice grains. A microbial fuel cell (MFC) system comprising graphite felt electrodes was also installed to generate electricity in the paddy field. The highest rice yield (9.0 ton/ha), dry mass (12.4 ton/ha), and protein content (13.1%), an important nutrient in animal feed, were obtained when a bottom-to-top irrigation (TWW was supplied to the underdrain pipe) was applied at the highest flow rate. The bottom-to-top irrigation achieved 79 to 91% removal of nitrogen in TWW, which was much higher than the top-to-top irrigation (58%). No accumulation of heavy metals was found in the experimental soils, and heavy metal concentrations in brown rice were lower than the allowable levels of current standards. The electric output from the MFC system was much lower than that reported in normal paddy fields, probably due to the poor connection between cables and electrodes. Further study is necessary to improve the electricity generation and to continuously monitor heavy metals in brown rice and the soil.

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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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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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Heavy metal interrelationships in soil in the presence of treated waste water

Global NEST Journal ◽

10.30955/gnj.000578 ◽

2013 ◽

Vol 11 (4) ◽

pp. 497-509

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Municipal Wastewater ◽

Block Design ◽

Scientific Basis ◽

Point Of View ◽

Brussels Sprouts ◽

Metal Interactions ◽

Randomized Block Design ◽

Treated Municipal Wastewater

An experiment was conducted in a greenhouse located in Agrinion, Greece, in order to study the effect of the treated municipal wastewater (TMWW) on the soil heavy metal interactions, in comparison to ordinary well irrigation water, denoted as control. The ultimate aim was the establishment of sound scientific basis for the TMWW reuse in the irrigation of vegetable production. A randomized block design was used including TMWW and the control, in six replications, the vegetable of Brassica oleracea var. Gemmifera (Brussels sprouts) being used as a test crop. The following were found: Forty interactions took place in the soil between heavy metals Pb, Ni, Co, Cd, Cu and Zn. Of these, 11 were significant under both the TMWW and the Control, respectively. Also, under only TMWW 15 interactions or 37.5% were statistically significant, while under the Control 21 or 52.5%. It was also shown that the effect of TMWW on most of the statistically significant interactions between heavy metals, did not differ significantly from that of the control, suggesting that from this point of view, the TMWW could be used for reuse in vegetable irrigation, provided that health risk related to microbiological factor is taken into account.

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