research article reuse feasibility of electrocoagulated...

Hindawi Publishing CorporationJournal of Waste ManagementVolume 2013 Article ID 686981 9 pageshttpdxdoiorg1011552013686981

Research ArticleReuse Feasibility of Electrocoagulated Metal Hydroxide Sludgeof Textile Industry in the Manufacturing of Building Blocks

Tanveer Mehedi Adyel12 Syed Hafizur Rahman3 Mohammad Moniruz Zaman4

Hossain Md Sayem5 Mala Khan6 Md Abdul Gafur7 and S M Nazrul Islam38

1 School of Environmental Systems EngineeringTheUniversity ofWestern Australia 35 Stirling Highway CrawleyWA 6009 Australia2 Department of Environmental Science Z H Sikder University of Science amp Technology Modhupur BhedergonjShariatpur Dhaka 8024 Bangladesh

3 Department of Environmental Sciences Jahangirnagar University Savar Dhaka 1342 Bangladesh4 Institute of Glass and Ceramic Research and Testing Bangladesh Council of Scientific and Industrial ResearchDhaka 1205 Bangladesh

5 Department of Geological Sciences Jahangirnagar University Dhaka 1342 Bangladesh6 Instrumentation and Calibration Service Laboratory Bangladesh Council of Scientific and Industrial ResearchDhaka 1205 Bangladesh

7 Pilot Plant and Process Development Center Bangladesh Council of Scientific and Industrial Research Dhaka 1205 Bangladesh8Department of Environmental Science and Engineering School of Natural Resources and Environmental StudiesUniversity of Northern British Columbia 3333 University Way Prince George BC Canada V2N 4Z9

Correspondence should be addressed to Tanveer Mehedi Adyel 21193926studentuwaeduau

Received 23 November 2012 Revised 4 January 2013 Accepted 12 January 2013

Academic Editor Weihua Song

Copyright copy 2013 Tanveer Mehedi Adyel et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

During the last decade the growing load of sludge from textile industries the top foreign exchange earning sector of Bangladesh isa common nuisance to environmental system and community healthThe present study was aimed to minimize the environmentalimpact from the disposal of Electrocoagulated Metal Hydroxide Sludge (EMHS) by using it as a partial substitute of clay in themanufacturing of construction material like building blocks (BBs) Different batches of normal and pressurized building blocks(NBBs and PBBs resp) were prepared using up to 50 EMHS with clay and then fired at a particular temperature EMHSproportion in the mixture and firing temperature were two key factors determining the quality of BB BB did not show anydeformation or uneven surfaces at any of the examined firing temperature At higher firing temperature and EMHS proportionmore weight loss and shrinkage of BB were noticed Higher compressive strength and lower water adsorption were found at lowerEMHS content and higher firing temperature It was explored that NBB and PBB with 20 and 30 EMHS in clay respectively andfired at 1050 ∘Cwould be usable for nonloading applications namely ornamental bricks decoration purposes and fence of garden

1 Introduction

Degradation of environmental quality due to unrestrictedand objectionable discharges of sludge from industrial unit isa common practice in developing countries like Bangladeshwhere little or no treatment of waste residue is carriedout before disposals in landfill site haphazardly or openlyAlthough textile and dyeing sector is a vital part of economicdevelopment speedy and unplanned progress may result in

a wide impact on natural resources and human being livingwithin the close vicinity of the sludge disposal locations[1ndash3] Electrocoagulated Metal Hydroxide Sludge (EMHS)produces during the treatment of waste effluent of the indus-try by electrocoagulation (EC) technique [4] where sacri-ficial anodes made of aluminum or iron corrode to releaseactive coagulant precursors [5ndash7] Coagulant produces insol-uble metallic hydroxide flocs which can remove pollutantsby surface complexation or electrostatic attraction [8 9]

2 Journal of Waste Management

Coagulants are in the form of both monomeric hydroxideions and highly charged polymeric metal hydroxyl speciesnamely Fe(H

2O)6

3+ Fe(H2O)5(OH)2+ Fe(H

2O)4(OH)2+

Fe2(H2O)8(OH)24+ Fe

2(H2O)6

(OH)4

4+ and so forth foranodes made of iron [10] These species neutralize theelectrostatic charges on the suspended solids and facilitateagglomeration resulting in separation from the aqueousphase by producing EMHS

Various steps have been taken by the Government ofBangladesh to monitor the effluent quality of industriesTherefore the volumes of wastewater treated and the quan-tities of sludge generated are increasing Hence recyclereuse and conversion of waste materials into a reusableone is critically important for environmental protection andsustainable development of the society Sludge contains awide range of components including organic and inorganicmatter bacteria and viruses oil and grease nutrients such asnitrogen and phosphorus toxic heavy and trace metals [11]So sustainable end use of this sludge is a paramount issueAlthough the landfills are commonly used for sludge disposalrapid urbanization has made it increasingly difficult to findsuitable landfill sites in Bangladesh

A potential long-term solution seems to be recycling ofthe EMHS sustainably and using it for beneficial purposesSolidification is such a technique that stabilizes and solidifiescomponents of waste materials The solidified products canbe disposed of to a secure landfill site or recycled andreused as construction materials namely bricks concretesroofing materials tiles building blocks (BBs) and so forthif meet the specific requirements [1ndash3 12 13] Utilization orreuse of EMHS as building materials is a win-win strategybecause it converts the waste materials into a useful oneand alleviates the disposal problem The prospective otherbenefits of using sludge as BB additives include oxidizingorganic matter immobilizing toxic and heavy metals inthe fired matrix destroying any pathogen during the firingprocess and reducing the frost damage based on the resultsof several full or bench scale studies [13ndash15] Although thereare related works on the sludge of sewage paper industrycommon effluent treatment plant of textile industry electro-plating industry and oil and petroleum industry to makeconstructional materials [13ndash25] no work is on EMHS reuseinto such materials Present study systematically investigatesthe partial replacement of clay or soil by EMHS in themanufacturing of buildingmaterials such asNormal BuildingBlock (NBB) and Pressurized Building Block (PBB) In orderto get quality products the influence of sludge proportion andfiring temperature on shrinkage weight loss water adsorp-tion and compressive strength were investigated Prior suchexamination basic geoengineering elemental thermal andmorphologicalmicrostructural properties of EMHS werealso analyzed The work was ultimately focused if the EMHSwill be feasible to reuse as building material in any extent

2 Materials and Methods

21 Samples Collection Preparation and Analysis The wetEMHS samples (119899 = 15) were collected from Adury Knit

Composite Ltd (Geographic Location 24∘021015840N latitude and90∘441015840E longitude) Narshingdi District Bangladesh Brick-making soil or clay samples (119899 = 12) were collected froma local brick field of Savar Dhaka District BangladeshBoth types of samples were separated into plastic containerslevelled with unique code and tagged and stored at ambientcondition prior to analysis For basic geoengineering prop-erties investigation EMHS was mixed with brick-makinggeneral soil or clay in triplicate at 10 20 30 and 40 onwet weight basis Moreover 100 soil and EMHS sampleswere also taken for comparison Samples were sun-driedand made powder using a grinder of aluminum oxide ballmaterial Powder samples that passed through 0853mmsievewere taken for elemental thermal and surface morphologi-calmicrostructural analysis and BB making process

Geoengineering elemental thermal and morphologi-calmicrostructural analysis of sampleswere carried out usingBritish Standard 1377 [26] ARL QUANTrsquoX EDXRF (ThermoScientific USA) TGDTA 6300 (Seiko Instruments IncJapan) at a heating range of 30∘C sim 1150∘C at 20∘Cminutein pure nitrogen gas medium and Scanning Electron Micro-scope (HITACHI S-3400N Japan) respectively Detailedprocedures were discussed elsewhere [1ndash3]

22 Preparation ofNBBandPBB Inmolding process ofNBBEMHS was mixed with soil up to 50 on weight basis in 10increment EMHS-free mixture was also made as a referenceDry mixing was done first and then 10 aqueous solution ofsodium silicate (Na

2SiO3) was added to make homogeneous

paste and bind the materials in the mixture well Mixtureswere then introduced into a series of BBmolds of 210158401015840times 210158401015840times 210158401015840Prod was applied with a wooden rod for 32 times in about 16seconds to ensure the elimination of entrained air After 24hours of maturation followed by drying at room temperaturedifferent batches of themolded blocks were fired at 950 1000and 1050∘C in a muffle furnace (Nabertherm Germany) for6 hours maintaining a soaking period of 15 minutes to get thefinal products In case of PBB EMHS was added to soil asthe same ratio of NBB Mixtures were then made into BB of210158401015840 times 210158401015840 times 210158401015840 at 5 ton pressure using a hydraulic press (FredS Carver Inc Wabash IN USA) Such pressure helped toachieve the block with compact shape which was first driedat room temperature followed by firing at 1000 and 1050∘C

23 Quality Assessment of NBB and PBB Fired BB specimenunderwent a series of test including weight loss on ignitionshrinkage on ignition water adsorption and compressivestrength to determine their quality using following equations

weight loss on ignition = Wa minusWbWa

firing shrinkage = Va minus VbVa

water adsorption = Wc minusWdWc

(1)

where Wa is the weight of BB before firing (gm) Wb is theweight of BB after firing (gm) Va is the volume of BB before

Journal of Waste Management 3

firing (cm3) Vb is the volume of BB after firing (cm3) Wc isthe weight of BB before water submersion (gm) and Wd isthe weight of BB after water submersion (gm)

Compressive strength of BB was determined using ahydraulic press (Fred S Carver Inc Wabash IN USA) Thetesting blocks were placed in the flat surface of the equipmentand then loadwas appliedWhen fracturewas observed in theblocks that loading pressure was taken and divided by four toget compressive strength in PSIThen this unit was convertedto kgcm2 where 1 PSI equivalent to 703069 times 10minus2 kgcm2

3 Results and Discussion

31 Geoengineering Elemental Thermal and MicrostructuralProperties of EMHS Basic geoengineering properties ofEMHS and EMHS amended soil were given in Figure 1 Allthe properties showed an increasing trend when EMHS wasadded with soil EMHS contained high specific gravity dueto the presence of very high iron content [1] EMHS was inhigh plasticity range if considered as soil-like material [1 27]Extremely high liquid limit value of EMHS might be due tothe high moisture content of EMHS Craig [28] mentionedthat most fine-grained soils existed naturally in the plasticstate and the plasticity due to the presence of clay mineralsor organic minerals High plastic limit of EMHS was arriveddue to the presence of organic matter from different typesof polymers and resins that were used in textile industryMeanwhile high linear shrinkage was caused for largemoisture content and liquid limit of the EMHS Shrinkage ofsoil was caused by the loss of pore water and has enormousdamage to structures built on or with clays Mitchell [29]mentioned that the greater the plasticity is the greater theshrinkage on drying becomes

Twenty-two elements were detected by EDXRF in EMHSwhere Fe was the dominant metal (about 83) Overallstatistics of elemental concentration was given in Table 1 FeMn Ni Cu Zn and Cd exceeded the permissible limit toapply EMHS as nutrient supplements in agricultural field[30ndash32] Cr andHg content in EMHS also has a great concerndue to their toxic effect to soil biota environment andhuman health Exposure of these metals from the sludgemay contaminate and change soil structure and thus becomesharmful for cultivation [32] EMHS was thermally moder-ately stable compared to soil due to the moisture content ofits porous surface and up to program temperature only 293weight of EMHS was degraded (Figure 2) EMHS sample wasunstructured in nature and irregular in shape with unevenedge and porous in body surface (Figure 3) Porosity onsurface was observed filling with a number of small grainsof other iron oxides such as maghemite or hematite [33] andformed a complex structure

32 Quality of NBB and PBB Initially BBs were consideredunsuitable if they developed cracks during drying and afterfiring at tested temperature or if deformation in the shapeor size was observed [34] All BBs of present work were ingood shape and size without any deformation at any firingtemperature Weight loss on ignition shrinkage on ignition

01

1

10

100

10000

10

20

30

40

100

Specific gravityLiquid limit ()Plastic limit ()

Liqidity indexPlasticity indexLinear shrinkage ()

Figure 1 Basic geoengineering properties of EMHS at differentmixing ratios with soil

Table 1 Statistics of elemental concentration (mgkg) of EMHS

Element Mean plusmn STD RangeFe 923812 plusmn 168 9026ndash9411Si 5107 plusmn 139 394ndash688Mg 7763 plusmn 636 10ndash157Ti 057 plusmn 008 048ndash067K 108 plusmn 04 072ndash166Ca 57 plusmn 04 53ndash62Cu 05 plusmn 02 034ndash078Ni 02 plusmn 005 012ndash024Zn 032 plusmn 003 028ndash034Mn 076 plusmn 034 023ndash098Zr 0048 plusmn 003 002ndash007Ba 011 plusmn 006 005ndash02Cr 0130 plusmn 0081 008ndash0250Cd 00145 plusmn 00032 001ndash0018V 01665 plusmn 0112 003ndash0300Hg 00550 plusmn 0010 005ndash0068Sr 00665 plusmn 0015 0052ndash0088Nb 00260 plusmn 0007 002ndash0035Ga 00105 plusmn 00012 0ndash0024Cl 000221 plusmn 00009 00012ndash00032Br 000957 plusmn 00008 0ndash008S 001197 plusmn 00022 0001ndash0015


1000800600400200

20

15

10

5

0 TG

100

80

60

40

20

0

1

08

06

04

02

0

55

233995

762 707

0051mgmin0066mgmin

0112mgminminus40

minus20

minus20

minus15

minus10

minus5

Temperature (∘C)

DTA

(120583V

)

DTG

(mg

min

)

811∘C

605∘C

901∘C

382∘C

308∘C

87∘C

45∘C

90∘C448 120583V

041 120583V

Figure 2 DTG-DTA-TG profile of EMHS

water adsorption and compressive strength were assessed asthe main criteria for quality of fired products

33Weight Loss on Ignition of NBB and PBB Higher percent-age of EMHSmixed with soil and fired at higher temperatureshowed more weight loss of NBB and PBB (Figure 4) NBBcontaining 50 EMHS and fired at 1000 and 1050∘C showedweight loss of 206 and 2162 respectively Weight lossoccurred due to the evaporation of water from productsmelting of inorganic substances and combustion of organicmatters during the firing process [13 14 34] A first classbrick has a maximum 15 weight loss on ignition [35] In thepresent study NBB containing up to 30 EMHS and firedat 950∘C 20 EMHS fired at 1000∘C and 10 EMHS firedat 1050∘C fulfilled the first class criteria Up to 20 EMHSwith soil and fired at all temperature regime PBB fulfilledthe first class standardThere were some small rough textureson the surfaces of BB due to organic matters being burntoff during the firing process When the firing temperaturewas higher than 950∘C the carbonate deformed to CO

2and

caused a weight loss of the BB When the temperature washigher than 1000∘C oxygen was recaptured from the air dueto the oxidation of iron and the large weight loss in the blockswas reduced [13 14] All BBs were attractive and appearedas light-to-deep red in color Esthetically the surface texturewas moderate even with the appearance of low small poresthereby it can be used as fencing and ornamental bricks [36]

34 Shrinkage on Ignition of NBB and PBB A good qualitybrick exhibits shrinkage below 8 [35] As swelling of clayis much lower than that of sludge addition of sludge to themixture widens the degree of firing shrinkage as a resultthe quality of products is downgraded [13] When firing

(a)

(b)

Figure 3 SEM micrograph of EMHS at (a) 100 120583m and (b) 10120583m

temperature and percentage of EMHSwith soil increased theshrinkage of the products also increased (Figure 5) Firingshrinkage of PBB increased rapidly up to 758 and 157 inaddition of 50 EMHS in the mixture and fired at 1000and 1050∘C respectively Shrinkage on ignition was not onlyattributed to the organic matter content of the sample butalso depended on the inorganic substances of both clay andsludge being burnt off during the firing process [13 14]PBBs with up to 50 EMHS and fired at 1000∘C were firstclass standard Moreover NBB with 10 EMHS and firedat 950∘C also fulfilled the national criteria of good qualityproducts [12] A linear relationship between weight loss andshrinkage on the ignition of BB was observed (Figure 6) Dueto shrinkage weight loss of BB occurred and vice versa

35 Water Adsorption of NBB and PBB Water adsorption isa crucial factor affecting the durability of various types ofbuilding materials The less the water infiltrates into blocksthe more the durability of the blocks and resistance to thenatural environment are exposed The degrees of firmnessand compaction of BB asmeasured by their water adsorptioncharacteristics vary considerably depending on the type ofclay and methods of production used Therefore the internal


4

8

12

16

20

24W

eigh

t los

s on

igni

tion

()

0 10 20 30 40 50Addition of EMHS with soil ()

1000∘C1050∘C

950∘C

(a)

5

10

15

20

25

0 10 20 30 40 50

Wei

ght l

oss o

n ig

nitio

n (

)

Addition of EMHS with soil ()

1000∘C1050∘C

(b)

Figure 4 Weight loss on ignition of (a) NBB and (b) PBB at different EMHS percentages and firing temperatures

5

10

15

20

25

Shri

nkag

e on

igni

tion

()


1000∘C1050∘C

950∘C

(a)

0

3

6

9

12

15

18

Shri

nkag

e on

igni

tion

()


1000∘C1050∘C

(b)

Figure 5 Shrinkage on ignition of (a) NBB and (b) PBB at different EMHS percentages and firing temperatures

structure of the BBmust be strong enough to avoid the intru-sion of much water Water adsorption of NBB was related tothe percentage of EMHS in mixtures (Figure 7) Increasingthe firing temperature resulted in a decrease of water adsorp-tion thereby increasing the weathering resistance

Water adsorption occurred in two stagesThe first stage ischaracterized by the linear behavior of gains of mass of waterwith time This phenomenon related to the larger capillary

pores In the second stage the gains of mass of water withtime followed a nonlinear behavior and the flow of water inmaterials occurs in the smaller capillary pores [37] Wateradsorption should be within 17 for the first class and 17 to22 for the second class brick [35] NBBs with 10 EMHSburnt at 1000ndash1050∘C were in the first class category NBBswith 10 EMHS fired at 950∘C 20 EMHS fired at 1000∘Cand 20ndash30EMHSfired at 1050∘C fall within the second class


05 10 15 20Weight loss on ignition ()

5

10

15

20

25

Shrin

kage

on

igni

tion

()

119910 = 1270119909 minus 2568

1198772= 0996

(a)

4

6

8

10

05 10 15 20 25

Shrin

kage

on

igni

tion

()

Weight loss on ignition ()

119910 = 0208119909 minus 3049

1198772= 0981

(b)

0 5 10 15 20 25Weight loss on ignition ()

5

10

15

20

25

Shri

nkag

e on

igni

tion

()

y = 1066x 1784minus

R2 = 0939

(c)


4

8

12

16

20

Shri

nkag

e on

igni

tion

()

y = 0711x 0497R2 = 0941minus

(d)


5

11

17

23

29

Shri

nkag

e on

igni

tion

()

y = 0794x 4549R2 = 0864

+

(e)

Figure 6 Relationship between weight loss and shrinkage on ignition of NBB at (a) 950∘C (c) 1000∘C and (e) 1050∘C and PBB at (b) 1000∘Cand (d) 1050∘C at different EMHS percentages

category PBB fired at 1050∘C containing with up to 40 ofEMHS in mixture were first class products while 50 EMHSin the mixture was second class Up to 30 EMHS with soilproduced the first class BB at 1000∘C (Figure 7) So PBBs

were more reliable than NBB in terms of water adsorptionproperty BB exhibited general compliance with some criteriafor load bearing bricks under class 1 and 2 because there areno specific requirements in these classes [19]


1000∘C1050∘C

950∘C

10

15

20

25

30

35W

ater

ads

orpt

ion

()


(a)

1000∘C1050∘C

5

9

13

17

21

Wat

er a

dsor

ptio

n (

)


(b)

Figure 7 Water adsorption of (a) NBB and (b) PBB at different EMHS percentages and firing temperatures

1000∘C1050∘C

950∘C

Com

pres

sive

stre

ngth

(kg

cm2

)

0

50

100

150


(a)

1000∘C1050∘C

50

100

150

200

Com

pres

sive

stre

ngth

(kg

cm2

)


(b)

Figure 8 Compressive strength of (a) NBB and (b) PBB at different EMHS percentages and firing temperatures

36 Compressive Strength of NBB and PBB All construc-tion materials must resist stress and strength of a materialindicated its ability to resist forces at failure It was greatlydependent on the amount of EMHS in the BB and thefiring temperature It decreased with the increase of EMHSin the mixture but increased with the increase of firingtemperature in case of NBB and PBB (Figure 8) Compressivestrength 150 kgcm2 was set for the first class brickblock and100 kgcm2 for the second class [35] NBB containing only soil

and fired at 1000 and 1050∘C showed compressive strengthof the second class brick PBB with 10 EMHS and fired at1050∘C reveled the first class standard [12] NBB with 20EMHS and PBB with 30 EMHS can be prescribed for theuses of nonloading purposes such as ornamental bricks anddecoration purpose fence of garden

There was a linear and statistically significant relationshipamong different properties of NBB with firing temperatureand percentage of EMHS in mixtures (Table 2) Various


Table 2 1198772 values of different properties of NBB at different firingtemperatures (950 1000 and 1050∘C) and percentages of EMHS insoil

1198772

0 10 20 30 40 50

Weight loss on ignition 095 097 096 095 089 096Shrinkage on ignition 081 085 099 098 098 098Compressive strength 081 083 08 085 097 068

metalsrsquo content in EMHS was subject to solidification indifferent BBs and hence ultimately reduced the disposalproblem of metals containing sludge

There are several mechanisms of solidification of heavymetals containing waste sludge [38] like Physical Encapsula-tionmdashas EMHS contained very small pores it could encap-sulate the contaminated particles AdsorptionmdashEMHS alsocontained a large number of micro and poorly crystallizedpores which led to a high specific surface area and so thatheavy metal ions can be adsorbed on the poorly crystallizedparticles Precipitationmdashthe hydration products of cementsuch as Ca(OH)

2led to a high alkaline environment and

many heavy metals can be transformed to hydroxides whichhave a very low solubility These hydroxides can be then pre-cipitated on the surface of the hydration products especiallyon the calcium silicate hydrates and in this way the heavymetals were immobilized

4 Conclusion

The textile industry is treated as the flagship of Bangladeshfor its contribution in top foreign exchange earning tradeof the country As the amount of sludge produced bywastewater or effluent treatment plant of such industriesis increased effective reuse and safe disposal of residuebecome a vital issue Sludge accumulation is a burden to theindustry and affects the environment adversely Present studysystematically investigated the reuse feasibility of EMHS fromtextile industry in the manufacturing of BB as a partialreplacement of soil To assess the quality weight loss onignition firing shrinkage water adsorption and compres-sive strength of the manufactured blocks were inspectedEMHS amount and firing temperature were two key factorsdetermining the overall merits of products Higher firingtemperature and EMHS proportion in the mixture resultedin an increase in weight loss and shrinkage of BB With theincreasing firing temperature and less EMHS proportion lesswater adsorption was observed Compressive strength of BBincreased with higher firing temperature and lower EMHSproportion EMHS containing up to 20 and 30 for NBBand PBB respectively and fired at 1050∘C produced goodquality blocks and these blocks can be used for nonloadingpurposesTherefore EMHS seems to be reused feasibly in themanufacturing of building materials like BB

Acknowledgments

This work was financially supported by the Ministry of Sci-ence Information and Communication Technology Peoples

Republic of Bangladesh under theNational Science Informa-tion and Communication Technology (NSICT) FellowshipThe authors are grateful for the thoughtful comments of twoanonymous reviewers

References

[1] T M Adyel S H Rahman S M N Islam H M SayemM Khan and M M Zaman ldquoGeo-engineering potentialityof electrocoagulated metal hydroxide sludge (EMHS) fromtextile industry and EMHS amended soil for using as buildingmaterialrdquo International Journal of Current Research vol 4 no2 pp 21ndash25 2012

[2] T M Adyel S H Rahman S M N Islam H M Sayem MKhan and M A Gafur ldquoCharacterization of brick making soilgeo-engineering elemental and thermal aspectsrdquo Jahangirna-gar University Journal of Science vol 35 no 1 pp 109ndash118 2012

[3] T M Adyel S H Rahman M Khan and S M N IslamldquoAnalysis of heavy metal in electrocoagulated metal hydroxidesludge (EMHS) from textile industry by energy dispersive X-rayfluorescence (EDXRF)rdquoMetals vol 2 no 4 pp 478ndash487 2012

[4] A K Golder A N Samanta and S Ray ldquoAnionic reactive dyeremoval from aqueous solution using a new adsorbent-sludgegenerated in removal of heavy metal by electrocoagulationrdquoChemical Engineering Journal vol 122 no 1-2 pp 107ndash115 2006

[5] S H Rahman S M N Islam N Kaiser and M M RahmanldquoElectrocoagulation (EC) for reduction of chemical oxygendemand (COD) of surface waterrdquo Bangladesh Journal of Scien-tific and Industrial Research vol 47 no 1 pp 77ndash82 2012

[6] S M N Islam S H Rahman T M Adyel et al ldquoElectrocoag-ulation (EC) technique for color removal from orange II dyerdquoBangladesh Journal of Environmental Research vol 9 pp 45ndash522011

[7] S M N Islam S H Rahman M M Rahman et al ldquoExcessiveturbidity removal from textile effluents using electrocoagula-tion (EC) techniquerdquo Journal of Scientific Research vol 3 no3 pp 557ndash568 2011

[8] M Y A Mollah R Schennach J R Parga and D L CockeldquoElectrocoagulation (EC)mdashscience and applicationsrdquo Journal ofHazardous Materials vol 84 no 1 pp 29ndash41 2001

[9] M Y A Mollah P Morkovsky J A G Gomes M KesmezJ Parga and D L Cocke ldquoFundamentals present and futureperspectives of electrocoagulationrdquo Journal of Hazardous Mate-rials vol 114 no 1ndash3 pp 199ndash210 2004

[10] A Amirtharajah and K M Mills ldquoRapid-mix design formechanisms of alum coagulationrdquo Journal American WaterWorks Association vol 74 no 4 pp 210ndash216 1982

[11] S H Rahman D Khanam T M Adyel M S Islam M AAhsan and M A Akbor ldquoAssessment of heavy metal contam-ination of agricultural soil around Dhaka export processingzone (DEPZ) Bangladesh implication of seasonal variation andindicesrdquo Applied Sciences vol 2 no 3 pp 584ndash601 2012

[12] M A Rouf and M D Hossain ldquoEffects of using arsenic-iron sludge in brick makingrdquo 2001 httpwwwunueduenvarsenicDhaka200315-Roufpdf

[13] C H Weng D F Lin and P C Chiang ldquoUtilization of sludgeas brick materialsrdquo Advances in Environmental Research vol 7no 3 pp 679ndash685 2003

[14] D F Lin and C H Weng ldquoUse of sewage sludge ash as brickmaterialrdquo Journal of Environmental Engineering vol 127 no 10pp 922ndash927 2001


[15] J H Tay and K Y Show ldquoConstructive sludge disposal optionconverting sludge into innovative civil engineering materialsrdquoin Proceeding of 7th International Association on Water Qual-ity (IAWQ) Asia-Pacific Regional Conference pp 1023ndash1028Taipei Taiwan 1999

[16] M Ismail M A Ismail S K Lau B Muhammad and ZMajidldquoFabrication of bricks from paper sludge and palm oil fuel ashrdquoConcreate Research Letter vol 1 no 2 pp 13ndash18 2010

[17] N T Ha T Yem and V T Mai ldquoStudy on reuse of heavymetal rich sludge in ceramic pigment and constructionmaterialproductionrdquo VNU Journal of Science Natural Sciences andTechnology vol 24 pp 280ndash286 2008

[18] L Chen and D F Lin ldquoApplications of sewage sludge ashand nano-SiO

2

to manufacture tile as construction materialrdquoConstruction and Building Materials vol 23 no 11 pp 3312ndash3320 2009

[19] A G Liew A Idris A A Samad C H K Wong M S Jaafarand A M Baki ldquoReusability of sewage sludge in clay bricksrdquoJournal of Material Cycles and Waste Management vol 6 no 1pp 41ndash47 2004

[20] J Balasubramanian P C Sabumon J U Lazar and R Ilango-van ldquoReuse of textile effluent treatment plant sludge in buildingmaterialsrdquoWaste Management vol 26 no 1 pp 22ndash28 2006

[21] R Baskar K M M S Begum and S Sundaram ldquoCharacteriza-tion and reuse of textile effluent treatment plant waste sludge inclay bricksrdquo Journal of the University Chemical Technology andMetallurgy vol 41 no 4 pp 473ndash478 2006

[22] E J Trauner ldquoSludge ash bricks fired to above and below ash-vitrifying temperaturerdquo Journal of Environmental Engineeringvol 119 no 3 pp 506ndash519 1993

[23] J H Tay and K Y Show ldquoManufacture of cement from sewagesludgerdquo Journal ofMaterials in Civil Engineering vol 5 no 1 pp19ndash29 1993

[24] J E Alleman E H Bryan T A Stumm W W Marlow andR CHocevar ldquoSludge-amended brick production applicabilityformetal-laden residuesrdquoWater Science and Technology vol 22no 12 pp 309ndash317 1990

[25] J H Tay ldquoBricks manufactured from sludgerdquo Journal Environ-mental Engineering vol 113 no 2 pp 278ndash283 1987

[26] British Standard 1377 Methods for Test for Civil EngineeringPurposes British Standard Institute London UK 1990

[27] K H Head Manual of Soil Laboratory Testing Pentech PressLondon UK 2nd edition 1992

[28] R F Craig Soil Mechanics Chapman and Hall London UK4th edition 1990

[29] J K Mitchell Fundamentals of Soil Behaviour John Willey ampSons New York NY USA 1976

[30] S K Awashthi Prevention of Food Adulteration Act no 37 of1954 Central and State Rules as Amended for 1999 Ashoka LawHouse New Delhi India 2000

[31] SEPAC (State Environmental Protection Administration ofChina) Chinese Environmental Quality Standard for Soils(GB15618-1995) Standards Press of China Beijing China 1995

[32] M M Islam M A Halim S Safiullah S A M W Hoqueand M S Islam ldquoHeavy metal (Pb Cd Zn Cu Cr Fe andMn) content in textile sludge in Gazipur Bangladeshrdquo ResearchJournal of Environmental Sciences vol 3 no 3 pp 311ndash315 2009

[33] M J UddinM SMiran andM Y AMollah ldquoElectrochemicalsynthesis and characterization of iron oxyhydroxiderdquo Journal ofBangladesh Chemical Society vol 20 pp 39ndash45 2007

[34] S RoyG RAdhikari andRNGupta ldquoUse of goldmill tailingsin making bricks a feasibility studyrdquo Waste Management andResearch vol 25 no 5 pp 475ndash482 2007

[35] ASTM (American Society of Testing Materials) ASTM C67Standard TestMethod for Sampling and Test Brick and StructuralClay Tile Annual Book of ASTM Standards Section 4 Con-struction 04 08 04 09 Soil and rock (I) and (II) ASTMWestConshohocken Pa USA 1998

[36] H M A Mahzuz R Alam M N Alam R Basak and M SIslam ldquoUse of arsenic contaminated sludge in making orna-mental bricksrdquo International Journal of Environmental Scienceand Technology vol 6 no 2 pp 291ndash298 2009

[37] C Hall ldquoWater sorptivity of mortars and concretes a reviewrdquoMagazine of Concrete Research vol 41 no 147 pp 51ndash61 1989

[38] D ZhangW Liu HHou andXHe ldquoStrength leachability andmicrostructure characterisation of Na

2

SiO3

-activated groundgranulated blast-furnace slag solidified MSWI fly ashrdquo WasteManagement and Research vol 25 no 5 pp 402ndash407 2007

Submit your manuscripts athttpwwwhindawicom

Forestry ResearchInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Environmental and Public Health

Journal of



EcosystemsJournal of


MeteorologyAdvances in

EcologyInternational Journal of


Marine BiologyJournal of


Hindawi Publishing Corporationhttpwwwhindawicom

Applied ampEnvironmentalSoil Science

Volume 2014

Advances in


Environmental Chemistry

Atmospheric SciencesInternational Journal of



Waste ManagementJournal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal of

Geophysics


Geological ResearchJournal of

EarthquakesJournal of


BiodiversityInternational Journal of


ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

OceanographyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


ClimatologyJournal of


Coagulants are in the form of both monomeric hydroxideions and highly charged polymeric metal hydroxyl speciesnamely Fe(H

2O)6

3+ Fe(H2O)5(OH)2+ Fe(H

2O)4(OH)2+

Fe2(H2O)8(OH)24+ Fe

2(H2O)6

(OH)4

4+ and so forth foranodes made of iron [10] These species neutralize theelectrostatic charges on the suspended solids and facilitateagglomeration resulting in separation from the aqueousphase by producing EMHS

Various steps have been taken by the Government ofBangladesh to monitor the effluent quality of industriesTherefore the volumes of wastewater treated and the quan-tities of sludge generated are increasing Hence recyclereuse and conversion of waste materials into a reusableone is critically important for environmental protection andsustainable development of the society Sludge contains awide range of components including organic and inorganicmatter bacteria and viruses oil and grease nutrients such asnitrogen and phosphorus toxic heavy and trace metals [11]So sustainable end use of this sludge is a paramount issueAlthough the landfills are commonly used for sludge disposalrapid urbanization has made it increasingly difficult to findsuitable landfill sites in Bangladesh

A potential long-term solution seems to be recycling ofthe EMHS sustainably and using it for beneficial purposesSolidification is such a technique that stabilizes and solidifiescomponents of waste materials The solidified products canbe disposed of to a secure landfill site or recycled andreused as construction materials namely bricks concretesroofing materials tiles building blocks (BBs) and so forthif meet the specific requirements [1ndash3 12 13] Utilization orreuse of EMHS as building materials is a win-win strategybecause it converts the waste materials into a useful oneand alleviates the disposal problem The prospective otherbenefits of using sludge as BB additives include oxidizingorganic matter immobilizing toxic and heavy metals inthe fired matrix destroying any pathogen during the firingprocess and reducing the frost damage based on the resultsof several full or bench scale studies [13ndash15] Although thereare related works on the sludge of sewage paper industrycommon effluent treatment plant of textile industry electro-plating industry and oil and petroleum industry to makeconstructional materials [13ndash25] no work is on EMHS reuseinto such materials Present study systematically investigatesthe partial replacement of clay or soil by EMHS in themanufacturing of buildingmaterials such asNormal BuildingBlock (NBB) and Pressurized Building Block (PBB) In orderto get quality products the influence of sludge proportion andfiring temperature on shrinkage weight loss water adsorp-tion and compressive strength were investigated Prior suchexamination basic geoengineering elemental thermal andmorphologicalmicrostructural properties of EMHS werealso analyzed The work was ultimately focused if the EMHSwill be feasible to reuse as building material in any extent

2 Materials and Methods

21 Samples Collection Preparation and Analysis The wetEMHS samples (119899 = 15) were collected from Adury Knit

Composite Ltd (Geographic Location 24∘021015840N latitude and90∘441015840E longitude) Narshingdi District Bangladesh Brick-making soil or clay samples (119899 = 12) were collected froma local brick field of Savar Dhaka District BangladeshBoth types of samples were separated into plastic containerslevelled with unique code and tagged and stored at ambientcondition prior to analysis For basic geoengineering prop-erties investigation EMHS was mixed with brick-makinggeneral soil or clay in triplicate at 10 20 30 and 40 onwet weight basis Moreover 100 soil and EMHS sampleswere also taken for comparison Samples were sun-driedand made powder using a grinder of aluminum oxide ballmaterial Powder samples that passed through 0853mmsievewere taken for elemental thermal and surface morphologi-calmicrostructural analysis and BB making process

Geoengineering elemental thermal and morphologi-calmicrostructural analysis of sampleswere carried out usingBritish Standard 1377 [26] ARL QUANTrsquoX EDXRF (ThermoScientific USA) TGDTA 6300 (Seiko Instruments IncJapan) at a heating range of 30∘C sim 1150∘C at 20∘Cminutein pure nitrogen gas medium and Scanning Electron Micro-scope (HITACHI S-3400N Japan) respectively Detailedprocedures were discussed elsewhere [1ndash3]

22 Preparation ofNBBandPBB Inmolding process ofNBBEMHS was mixed with soil up to 50 on weight basis in 10increment EMHS-free mixture was also made as a referenceDry mixing was done first and then 10 aqueous solution ofsodium silicate (Na

2SiO3) was added to make homogeneous

paste and bind the materials in the mixture well Mixtureswere then introduced into a series of BBmolds of 210158401015840times 210158401015840times 210158401015840Prod was applied with a wooden rod for 32 times in about 16seconds to ensure the elimination of entrained air After 24hours of maturation followed by drying at room temperaturedifferent batches of themolded blocks were fired at 950 1000and 1050∘C in a muffle furnace (Nabertherm Germany) for6 hours maintaining a soaking period of 15 minutes to get thefinal products In case of PBB EMHS was added to soil asthe same ratio of NBB Mixtures were then made into BB of210158401015840 times 210158401015840 times 210158401015840 at 5 ton pressure using a hydraulic press (FredS Carver Inc Wabash IN USA) Such pressure helped toachieve the block with compact shape which was first driedat room temperature followed by firing at 1000 and 1050∘C

23 Quality Assessment of NBB and PBB Fired BB specimenunderwent a series of test including weight loss on ignitionshrinkage on ignition water adsorption and compressivestrength to determine their quality using following equations

weight loss on ignition = Wa minusWbWa

firing shrinkage = Va minus VbVa

water adsorption = Wc minusWdWc

(1)

where Wa is the weight of BB before firing (gm) Wb is theweight of BB after firing (gm) Va is the volume of BB before








01

1

10

100

10000

10

20

30

40

100







1000800600400200

20

15

10

5

0 TG

100

80

60

40

20

0

1

08

06

04

02

0

55

233995

762 707

0051mgmin0066mgmin

0112mgminminus40

minus20

minus20

minus15

minus10

minus5

Temperature (∘C)

DTA

(120583V

)

DTG

(mg

min

)

811∘C

605∘C

901∘C

382∘C

308∘C

87∘C

45∘C

90∘C448 120583V

041 120583V




2and



(a)

(b)





4

8

12

16

20

24W

eigh

t los

s on

igni

tion

()


1000∘C1050∘C

950∘C

(a)

5

10

15

20

25

0 10 20 30 40 50

Wei

ght l

oss o

n ig

nitio

n (

)


1000∘C1050∘C

(b)


5

10

15

20

25

Shri

nkag

e on

igni

tion

()


1000∘C1050∘C

950∘C

(a)

0

3

6

9

12

15

18

Shri

nkag

e on

igni

tion

()


1000∘C1050∘C

(b)







5

10

15

20

25

Shrin

kage

on

igni

tion

()

119910 = 1270119909 minus 2568

1198772= 0996

(a)

4

6

8

10

05 10 15 20 25

Shrin

kage

on

igni

tion

()


119910 = 0208119909 minus 3049

1198772= 0981

(b)


5

10

15

20

25

Shri

nkag

e on

igni

tion

()

y = 1066x 1784minus

R2 = 0939

(c)


4

8

12

16

20

Shri

nkag

e on

igni

tion

()

y = 0711x 0497R2 = 0941minus

(d)


5

11

17

23

29

Shri

nkag

e on

igni

tion

()

y = 0794x 4549R2 = 0864

+

(e)





1000∘C1050∘C

950∘C

10

15

20

25

30

35W

ater

ads

orpt

ion

()


(a)

1000∘C1050∘C

5

9

13

17

21

Wat

er a

dsor

ptio

n (

)


(b)


1000∘C1050∘C

950∘C

Com

pres

sive

stre

ngth

(kg

cm2

)

0

50

100

150


(a)

1000∘C1050∘C

50

100

150

200

Com

pres

sive

stre

ngth

(kg

cm2

)


(b)







1198772

0 10 20 30 40 50






4 Conclusion


Acknowledgments



References




















2






















2

SiO3






Journal of












Volume 2014

Advances in









Geophysics





















01

1

10

100

10000

10

20

30

40

100







1000800600400200

20

15

10

5

0 TG

100

80

60

40

20

0

1

08

06

04

02

0

55

233995

762 707

0051mgmin0066mgmin

0112mgminminus40

minus20

minus20

minus15

minus10

minus5

Temperature (∘C)

DTA

(120583V

)

DTG

(mg

min

)

811∘C

605∘C

901∘C

382∘C

308∘C

87∘C

45∘C

90∘C448 120583V

041 120583V




2and



(a)

(b)





4

8

12

16

20

24W

eigh

t los

s on

igni

tion

()


1000∘C1050∘C

950∘C

(a)

5

10

15

20

25

0 10 20 30 40 50

Wei

ght l

oss o

n ig

nitio

n (

)


1000∘C1050∘C

(b)


5

10

15

20

25

Shri

nkag

e on

igni

tion

()


1000∘C1050∘C

950∘C

(a)

0

3

6

9

12

15

18

Shri

nkag

e on

igni

tion

()


1000∘C1050∘C

(b)







5

10

15

20

25

Shrin

kage

on

igni

tion

()

119910 = 1270119909 minus 2568

1198772= 0996

(a)

4

6

8

10

05 10 15 20 25

Shrin

kage

on

igni

tion

()


119910 = 0208119909 minus 3049

1198772= 0981

(b)


5

10

15

20

25

Shri

nkag

e on

igni

tion

()

y = 1066x 1784minus

R2 = 0939

(c)


4

8

12

16

20

Shri

nkag

e on

igni

tion

()

y = 0711x 0497R2 = 0941minus

(d)


5

11

17

23

29

Shri

nkag

e on

igni

tion

()

y = 0794x 4549R2 = 0864

+

(e)





1000∘C1050∘C

950∘C

10

15

20

25

30

35W

ater

ads

orpt

ion

()


(a)

1000∘C1050∘C

5

9

13

17

21

Wat

er a

dsor

ptio

n (

)


(b)


1000∘C1050∘C

950∘C

Com

pres

sive

stre

ngth

(kg

cm2

)

0

50

100

150


(a)

1000∘C1050∘C

50

100

150

200

Com

pres

sive

stre

ngth

(kg

cm2

)


(b)







1198772

0 10 20 30 40 50






4 Conclusion


Acknowledgments



References




















2






















2

SiO3






Journal of












Volume 2014

Advances in









Geophysics















1000800600400200

20

15

10

5

0 TG

100

80

60

40

20

0

1

08

06

04

02

0

55

233995

762 707

0051mgmin0066mgmin

0112mgminminus40

minus20

minus20

minus15

minus10

minus5

Temperature (∘C)

DTA

(120583V

)

DTG

(mg

min

)

811∘C

605∘C

901∘C

382∘C

308∘C

87∘C

45∘C

90∘C448 120583V

041 120583V




2and



(a)

(b)





4

8

12

16

20

24W

eigh

t los

s on

igni

tion

()


1000∘C1050∘C

950∘C

(a)

5

10

15

20

25

0 10 20 30 40 50

Wei

ght l

oss o

n ig

nitio

n (

)


1000∘C1050∘C

(b)


5

10

15

20

25

Shri

nkag

e on

igni

tion

()


1000∘C1050∘C

950∘C

(a)

0

3

6

9

12

15

18

Shri

nkag

e on

igni

tion

()


1000∘C1050∘C

(b)







5

10

15

20

25

Shrin

kage

on

igni

tion

()

119910 = 1270119909 minus 2568

1198772= 0996

(a)

4

6

8

10

05 10 15 20 25

Shrin

kage

on

igni

tion

()


119910 = 0208119909 minus 3049

1198772= 0981

(b)


5

10

15

20

25

Shri

nkag

e on

igni

tion

()

y = 1066x 1784minus

R2 = 0939

(c)


4

8

12

16

20

Shri

nkag

e on

igni

tion

()

y = 0711x 0497R2 = 0941minus

(d)


5

11

17

23

29

Shri

nkag

e on

igni

tion

()

y = 0794x 4549R2 = 0864

+

(e)





1000∘C1050∘C

950∘C

10

15

20

25

30

35W

ater

ads

orpt

ion

()


(a)

1000∘C1050∘C

5

9

13

17

21

Wat

er a

dsor

ptio

n (

)


(b)


1000∘C1050∘C

950∘C

Com

pres

sive

stre

ngth

(kg

cm2

)

0

50

100

150


(a)

1000∘C1050∘C

50

100

150

200

Com

pres

sive

stre

ngth

(kg

cm2

)


(b)







1198772

0 10 20 30 40 50






4 Conclusion


Acknowledgments



References




















2






















2

SiO3






Journal of












Volume 2014

Advances in









Geophysics















4

8

12

16

20

24W

eigh

t los

s on

igni

tion

()


1000∘C1050∘C

950∘C

(a)

5

10

15

20

25

0 10 20 30 40 50

Wei

ght l

oss o

n ig

nitio

n (

)


1000∘C1050∘C

(b)


5

10

15

20

25

Shri

nkag

e on

igni

tion

()


1000∘C1050∘C

950∘C

(a)

0

3

6

9

12

15

18

Shri

nkag

e on

igni

tion

()


1000∘C1050∘C

(b)







5

10

15

20

25

Shrin

kage

on

igni

tion

()

119910 = 1270119909 minus 2568

1198772= 0996

(a)

4

6

8

10

05 10 15 20 25

Shrin

kage

on

igni

tion

()


119910 = 0208119909 minus 3049

1198772= 0981

(b)


5

10

15

20

25

Shri

nkag

e on

igni

tion

()

y = 1066x 1784minus

R2 = 0939

(c)


4

8

12

16

20

Shri

nkag

e on

igni

tion

()

y = 0711x 0497R2 = 0941minus

(d)


5

11

17

23

29

Shri

nkag

e on

igni

tion

()

y = 0794x 4549R2 = 0864

+

(e)





1000∘C1050∘C

950∘C

10

15

20

25

30

35W

ater

ads

orpt

ion

()


(a)

1000∘C1050∘C

5

9

13

17

21

Wat

er a

dsor

ptio

n (

)


(b)


1000∘C1050∘C

950∘C

Com

pres

sive

stre

ngth

(kg

cm2

)

0

50

100

150


(a)

1000∘C1050∘C

50

100

150

200

Com

pres

sive

stre

ngth

(kg

cm2

)


(b)







1198772

0 10 20 30 40 50






4 Conclusion


Acknowledgments



References




















2






















2

SiO3






Journal of












Volume 2014

Advances in









Geophysics
















5

10

15

20

25

Shrin

kage

on

igni

tion

()

119910 = 1270119909 minus 2568

1198772= 0996

(a)

4

6

8

10

05 10 15 20 25

Shrin

kage

on

igni

tion

()


119910 = 0208119909 minus 3049

1198772= 0981

(b)


5

10

15

20

25

Shri

nkag

e on

igni

tion

()

y = 1066x 1784minus

R2 = 0939

(c)


4

8

12

16

20

Shri

nkag

e on

igni

tion

()

y = 0711x 0497R2 = 0941minus

(d)


5

11

17

23

29

Shri

nkag

e on

igni

tion

()

y = 0794x 4549R2 = 0864

+

(e)





1000∘C1050∘C

950∘C

10

15

20

25

30

35W

ater

ads

orpt

ion

()


(a)

1000∘C1050∘C

5

9

13

17

21

Wat

er a

dsor

ptio

n (

)


(b)


1000∘C1050∘C

950∘C

Com

pres

sive

stre

ngth

(kg

cm2

)

0

50

100

150


(a)

1000∘C1050∘C

50

100

150

200

Com

pres

sive

stre

ngth

(kg

cm2

)


(b)







1198772

0 10 20 30 40 50






4 Conclusion


Acknowledgments



References




















2






















2

SiO3






Journal of












Volume 2014

Advances in









Geophysics















1000∘C1050∘C

950∘C

10

15

20

25

30

35W

ater

ads

orpt

ion

()


(a)

1000∘C1050∘C

5

9

13

17

21

Wat

er a

dsor

ptio

n (

)


(b)


1000∘C1050∘C

950∘C

Com

pres

sive

stre

ngth

(kg

cm2

)

0

50

100

150


(a)

1000∘C1050∘C

50

100

150

200

Com

pres

sive

stre

ngth

(kg

cm2

)


(b)







1198772

0 10 20 30 40 50






4 Conclusion


Acknowledgments



References




















2






















2

SiO3






Journal of












Volume 2014

Advances in









Geophysics
















1198772

0 10 20 30 40 50






4 Conclusion


Acknowledgments



References




















2






















2

SiO3






Journal of












Volume 2014

Advances in









Geophysics



















2






















2

SiO3






Journal of












Volume 2014

Advances in









Geophysics


















Journal of












Volume 2014

Advances in









Geophysics














research article reuse feasibility of electrocoagulated...

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