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http://www.iaeme.com/IJCIET/index.asp 8 [email protected] International Journal of Civil Engineering and Technology (IJCIET) Volume 6, Issue 9, Sep 2015, pp. 08-19, Article ID: IJCIET_06_09_002 Available online at http://www.iaeme.com/IJCIET/issues.asp?JTypeIJCIET&VType=6&IType=9 ISSN Print: 0976-6308 and ISSN Online: 0976-6316 © IAEME Publication ___________________________________________________________________________ COLUMN STUDY OF THE ADSORPTION OF PHOSPHATE BY USING DRINKING WATER TREATMENT SLUDGE AND RED MUD Prof. Dr. Alaa Hussein Al-Fatlawi College of Engineering / Babylon University/Iraq Mena Muwafaq Neamah College of Engineering / Babylon University/Iraq ABSTRACT The present study investigates the efficiency of phosphate removal from wastewater by the Drinking Water Treatment Sludge (DWTS), and Red Mud (RM) sorbent. Wastewater was taken from the effluent channel of Almuamirah wastewater treatment plantin at Al-Hilla city/Iraq. Drinking Water Treatment Sludge (DWTS), was taken from the sedimentation tanks of Al-Tayara drinking water treatment plant, in the same city. Column experiment was carried out to study the adsorption isotherm of phosphorus at 25±1C and solution of different pH and adsorbent dosages. The effects of (DWTS) dose, bed height (H), contact time (T), agitation speed (S), hydrogen ion concentration (pH), (DWTS RM) ratio, were studied. All continuous experiments were conducted at constant conditions, bed depths 25 cm, initial phosphate concentration 4 mg/L, flow rate 5 mL/min, particle size (1mm) for (DWTS), and (0.425mm) for (RM) and solution pH of 4. The results show that the use of (RM) reduces the operating time by about 21% compared to the use of (DWTS).Increasing (RM) ratio increasing the removal efficiency and decreasing the equilibrium time in about 57% and 38% for 50% and 33% (RM) ratio respectively. At the highest phosphate concentration of 4 mg/l, the (DWTS) bed was exhausted in the shortest time of less than 9 hours leading to the earliest breakthrough. Percent of phosphate removal decreased with the increase in initial concentration. Both the breakthrough and exhaustion time increased with increasing the bed height. The results show that a significant increase in the operating time is achieved by adding different ratios of (RM) to (DWTS). Adding 33%, and 50 % (RM) weight ratios to the (DWTS) bed decreases the operating time by about 18%, and 30% respectively.

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  • http://www.iaeme.com/IJCIET/index.asp 8 [email protected]

    International Journal of Civil Engineering and Technology (IJCIET)

    Volume 6, Issue 9, Sep 2015, pp. 08-19, Article ID: IJCIET_06_09_002

    Available online at

    http://www.iaeme.com/IJCIET/issues.asp?JTypeIJCIET&VType=6&IType=9

    ISSN Print: 0976-6308 and ISSN Online: 0976-6316

    © IAEME Publication

    ___________________________________________________________________________

    COLUMN STUDY OF THE ADSORPTION OF

    PHOSPHATE BY USING DRINKING WATER

    TREATMENT SLUDGE AND RED MUD

    Prof. Dr. Alaa Hussein Al-Fatlawi

    College of Engineering / Babylon University/Iraq

    Mena Muwafaq Neamah

    College of Engineering / Babylon University/Iraq

    ABSTRACT

    The present study investigates the efficiency of phosphate removal from

    wastewater by the Drinking Water Treatment Sludge (DWTS), and Red Mud

    (RM) sorbent. Wastewater was taken from the effluent channel of Almuamirah

    wastewater treatment plantin at Al-Hilla city/Iraq. Drinking Water Treatment

    Sludge (DWTS), was taken from the sedimentation tanks of Al-Tayara drinking

    water treatment plant, in the same city.

    Column experiment was carried out to study the adsorption isotherm of

    phosphorus at 25±1⁰C and solution of different pH and adsorbent dosages. The effects of (DWTS) dose, bed height (H), contact time (T), agitation speed

    (S), hydrogen ion concentration (pH), (DWTS –RM) ratio, were studied.

    All continuous experiments were conducted at constant conditions, bed

    depths 25 cm, initial phosphate concentration 4 mg/L, flow rate 5 mL/min,

    particle size (1mm) for (DWTS), and (0.425mm) for (RM) and solution pH of

    4.

    The results show that the use of (RM) reduces the operating time by about

    21% compared to the use of (DWTS).Increasing (RM) ratio increasing the

    removal efficiency and decreasing the equilibrium time in about 57% and 38%

    for 50% and 33% (RM) ratio respectively.

    At the highest phosphate concentration of 4 mg/l, the (DWTS) bed was

    exhausted in the shortest time of less than 9 hours leading to the earliest

    breakthrough. Percent of phosphate removal decreased with the increase in

    initial concentration. Both the breakthrough and exhaustion time increased

    with increasing the bed height.

    The results show that a significant increase in the operating time is

    achieved by adding different ratios of (RM) to (DWTS). Adding 33%, and 50

    % (RM) weight ratios to the (DWTS) bed decreases the operating time by

    about 18%, and 30% respectively.

  • Column Study of The Adsorption of Phosphate by Using Drinking Water Treatment Sludge

    and Red Mud

    http://www.iaeme.com/IJCIET/index.asp 9 [email protected]

    Key words: Column Study, Adsorption, Drinking Water Treatment Sludge

    (DWTS), and Red Mud (RM), phosphate.

    Cite this Article: Prof. Dr. Alaa Hussein Al-Fatlawi and Mena Muwafaq

    Neamah. Investigating Column Study of The Adsorption of Phosphate by

    Using Drinking Water Treatment Sludge and Red Mud. International Journal

    of Civil Engineering and Technology, 6(9), 2015, pp. 08-19.

    http://www.iaeme.com/IJCIET/issues.asp?JTypeIJCIET&VType=6&IType=9

    1. INTRODUCTION

    Phosphorus (P) is an essential nutrient for the growth of organisms in most

    ecosystems, but superfluous phosphorus can also cause eutrophication and hence

    deteriorate water quality. Phosphorus is released into aquatic environments in many

    ways, of which the most significant are human industrial, agricultural, and mining

    activities. Although phosphorus removal is required before discharging wastewater

    into bodies of water, phosphorus pollution is nevertheless increasing. Therefore, there

    is currently an urgent demand for improved phosphorus removal methods which can

    be applied before wastewater discharge. In wastewater treatment, enhanced biological

    phosphorus removal (EBPR) is becoming an increasingly popular alternative to

    chemical precipitation (CP) because of its lower costs and reduced sludge production.

    Much water treatment sludge is produced in the production of service water and

    drinking water. It is impossible to prevent the production of water treatment sludge.

    The water treatment sludge is liquid and solid and is regarded as a waste.

    Consequently, the water treatment sludge must be handled in accordance with

    regulations in forces. The quantity of the water treatment sludge is rather high. The

    water treatment sludge is placed mostly in landfills. In some countries, for instance in

    the Netherlands, about 25 per cent of the produced water treatment sludge is re-used,

    (Miroslav, 2008).

    It is still an issue to choose a disposal or liquidation method for the water

    treatment sludge that would be reasonable in terms of technology and economy.

    According to environment protection regulations it is required to minimise the

    quantity of wastes produced. If possible, the wastes should be re-used or processed as

    secondary raw materials as much as possible. If this is not possible, the solid wastes

    should be put back in the environment where the space occupied should be as little as

    possible and minimum costs should be incurred, (Moldan et al., 1990).

    Phosphorus removal from wastewater has been widely investigated and several

    techniques have been developed including adsorption methods, physical processes

    (settling, filtration), chemical precipitation (with aluminum, iron and calcium salts),

    and biological processes that rely on biomass growth (bacteria, algae, plants) or

    intracellular bacterial polyphosphates accumulation (de-Bashan et al., 2004).

    Recently, the removal of phosphate from aqueous solutions via adsorption has

    attracted much attention. The key problem for many phosphorus adsorption methods,

    however, is finding an efficient adsorbent. Several low-cost or easily available clays,

    waste materials and by-products.

  • Prof. Dr. Alaa Hussein Al-Fatlawi and Mena Muwafaq Neamah

    http://www.iaeme.com/IJCIET/index.asp 10 [email protected]

    2. MATERIAL AND METHODS

    2.1 Adsorbate

    Phosphate was selected as a representative of a contaminant because the it is the main

    nutrient for the growth of aquatic microorganisms like algae but the excess content of

    phosphorus in receiving waters leads to extensive algae growth (eutrophication).

    The samples was collected from the effluent channel of Almuamirah wastewater

    treatment plant in Al-Hilla city, Iraq. These samples were immediately transported to

    the laboratory for processing. The total amount of plant nutrients and other pollutants

    present in a sewage plant effluent is subjected to seasonal, daily, and hourly variation.

    Table 1 summarizes the composition and variability of the effluent under study. The

    wastewater sample was used as stock solution to provide the specific value of

    phosphate concentration. Where necessary, pH adjustment was made on each sample

    by addition of 0.1 M HNO3 and NaOH solutions using a HACH-pH meter.

    Table 1 Physico-chemical analysis of secondary wastewater effluent sample, (Almuamirah

    wastewater treatment plant, 2014)

    parameters Quantitative composition

    E.C, µs/cm 3.5

    T.D.S, mg/L 1288

    Salinity, mg/L 2.18

    Total hardness, as CaCo3, mg/L 1200

    pH 7.9

    Mg, mg/L 232.8

    Ca, mg/L 160.3

    So4, mg/L 769.4

    Cl, mg/L 289.9

    Po4, mg/L 2.7

    No3, mg/L 0.46

    T.S.S, mg/L 40

    BOD5, mg/L 32

    COD, mg/L 54

    DO, mg/L 2.3

    Fecal coliform, mpn/100 ml 120000

    Total coliform, mpn/100 ml 128000

    2.2 Adsorbent

    Two types of adsorbent were used in the present study for adsorption of phosphate

    from secondary effluents of wastewater treatment plant they are:

    1. Drinking Water Treatment Sludge (DWTS),

    2. Red Mud (RM).

    2.2.1. Drinking Water Treatment Sludge (DWTS)

    The composition and properties of the water treatment sludge depends typically on the

    quality of treated water as well as on types and doses of chemicals used during the

  • Column Study of The Adsorption of Phosphate by Using Drinking Water Treatment Sludge

    and Red Mud

    http://www.iaeme.com/IJCIET/index.asp 11 [email protected]

    water treatment. Depending on the quality of the treated water, the water treatment

    sludge contains suspensions of inorganic and organic substances.

    The (DWTS) used in this study was taken from the sedimentation tanks of Al-

    Tayara drinking water treatment plant, in Al-Hilla city, Iraq. This sludge was dried at

    atmospheric temperature for 5 days, and then sieved on 2 mm mesh to achieve

    satisfactory uniformity. The sludge had a particle size distribution ranged from 150

    μm to 10 mm (Fig. 1) with an effective grain size, d10, of 250 μm, a median grain size,

    d50, of 460 μm and a uniformity coefficient, Cu= d60/d10, of 2.24.

    Figure 1 Gradation curve for (DWTS) used in the present study.

    The geometric mean diameter (1.19) is given by where d1 is the

    diameter of lower sieve on which the particles are retained and d2 is the diameter of

    the upper sieve through which the particles pass (Alexander and Zayas, 1989). Table

    2 presents the physical and chemical characteristics of this (DWTS).

    Table 2 Physical and chemical characteristics of DWTS

    Element Quantitative composition

    T.O.C, mg/L 4.29

    E.C, µs/cm 620

    T.D.S, mg/L 312

    Salinity, mg/L 0.2

    pH 8.1

    L.O.I, mg/L 15.76

    Fe2O3, mg/L 3.6

    CaO, mg/L 15.32

    SO3, mg/L 0.63

    MgO, mg/L 3.66

    Al2O3, mg/L 11.56

    R2O3, mg/L 15.16

    SiO2, mg/L 45

    2.2.2. Red Mud (RM)

    The Red Mud (RM) used in this study was supplied by the Iraqi commercial markets.

    It is a solid waste produced in the process of alumina production from bauxite

    following the Bayer process. Red mud, as the name suggests, is brick—red in colour

    and slimy, having an average particle size of

  • Prof. Dr. Alaa Hussein Al-Fatlawi and Mena Muwafaq Neamah

    http://www.iaeme.com/IJCIET/index.asp 12 [email protected]

    20μm are also available [Liu et al., 2011].The mesh size of red mud used in the study

    was of 1mm. This size was obtained by sieving analysis using the American Sieve

    Standards in the building of Materials Engineering laboratory at the University of

    Babylon. Its composition, property and phase vary with the type of the bauxite and the

    alumina production process, and also change over time. The chemical composition of

    the red mud is given in Table 3.

    As a pre-treatment, (RM) was crushed and sieved to get granular (RM)with

    particle size of 0.425 mm to be used in present experiments as shown in Fig. 2.The

    granular (RM) was firstly washed with distilled water and then dried in an electric

    oven at 120⁰C, overnight. This time was usually enough to remove any undesired moisture within the particles. It was then placed in desiccators for cooling.

    Figure 2 Gradation curve for (RM) used in the present study.

    Table 3 The main chemical constituents of (RM), (Ping and Dong, 2012)

    Chemical constituent Quantitative composition, %

    Fe2O3 26.41

    Al2O3 18.94

    SiO2 8.52

    CaO 21.84

    Na2O 4.75

    TiO2 7.40

    K2O 0.068

    Sc2O3 0.76

    V2O5 0.34

    Nb2O5 0.008

    TREO 0.012

    Loss 9.71

    0

    20

    40

    60

    80

    100

    120

    0.1 1 10

    % o

    f cu

    mu

    lati

    ve p

    assi

    ng

    Partical size (diameter , mm)

  • Column Study of The Adsorption of Phosphate by Using Drinking Water Treatment Sludge

    and Red Mud

    http://www.iaeme.com/IJCIET/index.asp 13 [email protected]

    3. PREPARATION OF SAMPLES WITH DIFFERENT (DWTS)

    AND (RM) RATIOS

    Two different (DWTS) and (RM) weight and ratios of (DWTS) to (RM) were used

    starting with 0%, 33% and then 50%. The added (DWTS) was with a size of 1mm

    while the size of (RM) was of 0.425mm. Each sample was mixed by shaking using a

    shaker for 1 hour. The 0% ratio was first prepared and used in the experiments. When

    an increase in the operating time was achieved, the addition ratio was raised to 50%.

    4. EXPERIMENTAL PROCEDURES

    The reactor setup (Fig. 3) used in the present study is constructed of pyrex glass tube

    of (100 cm) height, and (7.5 cm) internal diameter. The column was made in a

    methacrylate cylinder, thus allowing for visual examination of the progress of the

    wetting front and detection of preferential flow channels along the column walls. The

    column dimensions were defined to minimize the occurrence of channeling by

    making the column diameter at least 30 times the maximum particle size found in the

    material used. The column dimensions also met the minimum length-to-diameter

    requirement (Relyea, 1982). This means the column length (100 cm) must be four

    times greater than its diameter (7.5 cm). Attached to the lower part of the column was

    a plastic funnel, inside which a perforated fiberglass plate was installed to support the

    column’s methacrylate structure. The plate was covered by a mesh to act as a filter

    and to retain the porous medium. The entire device was mounted on top of a metal

    structure that allowed its height above the surface and the verticality of the column to

    be regulated (Fig. 3). The column was packed with (DWTS) and (RM) in different

    ratios as filter. Fluid entered the column, previously saturated with the wastewater.

    Contaminant up gradient wastewater (Table 1) was used to flow through the layer of

    packed materials. A constant-head reservoir of 50 liter volume polyethylene container

    was used to deliver influent wastewater at a flow rate of 5 mL/min. The sample was

    collected as a function of time at the bottom of the column through a 30 liter

    polyethylene container to collect the effluent solution. Two valves were used to

    control the desired flow rate through the adsorption column. The first sample,

    corresponding to time 0, was taken when water started to flow from the lower part of

    the column. Samples were filtered through 0.45µm cellulose acetate filters.

    Figure 3 Experimental set-up of column test used in the present study.

    Monitoring of phosphate concentrations in the effluent was conducted for a period

    of 120 hr. Samples were taken regularly (after different periods) from the effluent.

    The water samples were immediately introduced in glass vials and then analyzed by

    AAS.

  • Prof. Dr. Alaa Hussein Al-Fatlawi and Mena Muwafaq Neamah

    http://www.iaeme.com/IJCIET/index.asp 14 [email protected]

    The filling material in the column was assumed to be homogeneous and

    incompressible, and constant over time for water-filled porosity. The volumetric water

    discharge through the column cross section was constant over time and set as the

    experimental values. The pollutant inlet concentration was set constant. All tubing

    and fitting for the influent and effluent lines should be composed of an inert material.

    Information from the column study can be used along with the site characterization

    and modeling to help in designs the field-scale (DWTS).

    5. RESULTS AND DISCUSSIONS

    The adsorption experiments were carried out in columns that were equipped with a

    stopper for controlling the column flow rate. This experiment is useful in

    understanding and predicting the behavior of the process. The sample solution was

    passed through the adsorption column with a known amount of (DWTS) at a flow rate

    of 5mL/min by gravity. The flow rate was kept constant by controlling the stopper

    valve. The concentration of phosphate residual in the sorption medium was

    determined using fully automated PC-controlled true double-beam AAS with fast

    sequential operation (Varian AA50 FS, Australia) for fast multielement flame AA

    determinations with features 4 lamp positions and automatic lamp selection.

    The results of phosphate adsorption onto different adsorption fixed beds using a

    continuous system were presented in the form of breakthrough curves which showed

    the loading behaviors of phosphate to be adsorbed from the solution expressed in

    terms of relative concentration defined as the ratio of the outlet phosphate

    concentration to the inlet phosphate concentration as a function of time (Ce/C₀ vs. time).

    5.2. Breakthrough Curves of the Different Adsorbents

    Two continuous flow adsorption experiments were conducted to study the adsorption

    behavior of fixed beds of (DWTS), and (RM). All the experiments were conducted at

    constant conditions, bed depths 25 cm, initial phosphate concentration 4 mg/L, flow

    rate 5 mL/min, particle size (1mm) for (DWTS), and (0.425mm) for (RM) and

    solution pH of 4. The breakthrough curves of the experiments are presented in Fig. 4

    in terms of Ce/C₀ versus time in minutes.

    Figure 4 Experimental breakthrough curves for adsorption of phosphate onto DWTS and RM

    at C₀=4 mg/L, pH=4, Temp. = 25 ⁰C, H= 25 cm.

    0

    0.2

    0.4

    0.6

    0.8

    1

    1.2

    0 1000 2000 3000 4000

    Ce

    /C

    Time, min.

    DWTS

    RM

  • Column Study of The Adsorption of Phosphate by Using Drinking Water Treatment Sludge

    and Red Mud

    http://www.iaeme.com/IJCIET/index.asp 15 [email protected]

    Fig. 4 shows that the two adsorbents used in present study are efficient in the

    removal of phosphate. The use of (RM) reduces the operating time by about 21%

    compared to the use of (DWTS). It is obvious from this figure that the breakthrough

    curves for the two adsorbents used are of S shape.

    5.2. Effect of Initial phosphate Concentration

    The effect of changing of phosphate concentration from 2.7 mg/l to 4 mg/l with

    constant bed height of (DWTS) of 25 cm, flow rate of 5 mL/min, and solution pH of 4

    is shown by the breakthrough curves presented in Fig. 5. At the highest phosphate

    concentration of 4 mg/l, the (DWTS) bed was exhausted in the shortest time of less

    than 9 hours while its 50 hours for (RM).Leading to the earliest breakthrough. The

    breakpoint time decreased with increasing the initial concentration as the binding sites

    became more quickly saturated in the column. This indicated that an increase in the

    concentration could modify the adsorption rate through the bed. A decrease in the

    phosphate concentration gave an extended breakthrough curve indicating that a higher

    volume of the solution could be treated. This was due to the fact that a lower

    concentration gradient caused a slower transport due to a decrease in the diffusion

    coefficient or mass transfer coefficient.

    The effect of initial phosphate concentration onto (DWTS) and (RM) are shown

    here (Fig. 5 and 6). It could be seen that the percent of phosphate removal decreased

    with the increase in initial concentration. This means that the amount of these

    phosphate sorbed per unit mass of sorbent increased with the increase in initial

    concentration. This plateau represents saturation of the active sites available on the

    (DWTS) samples for interaction with contaminants, indicating that less favorable sites

    became involved in the process with increasing concentration.

    Figure 5 Experimental breakthrough curves for adsorption of phosphorus onto DWTS at

    different initial concentrations, pH=4, H=25 cm, Temp.=25 ⁰C.

    0

    0.2

    0.4

    0.6

    0.8

    1

    0 1000 2000 3000 4000

    Cₑ

    /C₀

    Time, min.

    C=2.7 mg/L

    C=4 mg/L

  • Prof. Dr. Alaa Hussein Al-Fatlawi and Mena Muwafaq Neamah

    http://www.iaeme.com/IJCIET/index.asp 16 [email protected]

    Figure 6 Experimental breakthrough curves for adsorption of phosphorus onto RM at

    different initial concentrations, pH=4, H=25 cm, Temp.=25 ⁰C.

    5.3. Effect of Adsorbent Bed Height

    The effect of bed height was investigated for phosphorus adsorption onto (DWTS); the experimental breakthrough curves are presented in Fig. 7. This Fig. shows the

    breakthrough curves obtained for phosphate adsorption on the (DWTS) for five

    different bed heights of (5, 10, 15, 20, and 25 cm), at a constant flow rate of 5

    mL/min, phosphate initial concentration of 4 mg/L, and solution pH of 4.It is clear

    that the increase in bed depth increases the breakthrough time and the residence time

    of the solute in the column.

    Both the breakthrough and exhaustion time increased with increasing the bed

    height. A higher phosphate uptake was also expected at a higher bed height due to the

    increase in the specific surface of the (DWTS) which provides more fixation binding

    sites for the phosphate to adsorb. The increase in the adsorbent mass in a higher bed

    provided a greater service area which would lead to an increase in the volume of the

    solution treated. (Gupta et al., 2001) reported in their works that when the bed height

    is reduced, axial dispersion phenomena predominates in the mass transfer and reduces

    the diffusion of the solute, and therefore, the solute has not enough time to diffuse

    into the whole of the adsorbent mass.

    The effect of bed depth on the adsorption capacity of (DWTS) was shown in

    Fig.8, by plotting the capacity versus different bed depth. This Fig. shows that

    increasing bed depth would increase the capacity because additional spaces will be

    available for the wastewater molecules to be adsorbed on these unoccupied areas.

    Furthermore, increasing bed depth will give a sufficient contact time for these

    molecules to be adsorbed on the (DWTS) surface.

    0

    0.2

    0.4

    0.6

    0.8

    1

    1.2

    0 100 200 300 400 500 600

    Cₑ/

    C₀

    Time, min.

    C=2.7 mg/L

    C=4 mg/L

  • Column Study of The Adsorption of Phosphate by Using Drinking Water Treatment Sludge

    and Red Mud

    http://www.iaeme.com/IJCIET/index.asp 17 [email protected]

    Figure 7 Experimental breakthrough curves for adsorption of phosphorus onto DWTS at

    different bed thickness C₀=4 mg/L, pH=4, Temp.=25 ⁰C.

    Figure 8 Effect of different bed depth on the adsorption capacity of DWTS (Q=5 mL/min,

    C₀=4 mg/L, pH=4, Temp=25 ⁰C).

    5.4. Effect of Different (DWTS) – (RM) Ratios

    The effect of different (DWTS) – (RM) weight ratios were investigated for phosphate

    adsorption onto (DWTS) by adding different weight ratios of (0.425mm particle size)

    (RM) to the (DWTS) bed which was of (1 mm particle size). Three experiments were

    conducted using different weight ratios of (DWTS) – (RM) (0%, 33%, and 50%). All

    experiments were carried out at constant conditions, flow rate of 5 mL/min, initial

    phosphate concentration of 4 mg/L, (DWTS) bed height of 25 cm, and solution pH of

    4. The experimental breakthrough curves are presented in Fig. 9.

    This Fig. shows that a significant decrease in the operating time is achieved by

    adding different ratios of (RM) to (DWTS). Adding 33%, and 50 % (RM) weight

    ratios to the (DWTS) bed decreases the operating time by about 18%, and 30%

    respectively. In the packed bed of the (DWTS) column, the contact points between the

    0

    0.2

    0.4

    0.6

    0.8

    1

    1.2

    0 1000 2000 3000 4000

    Cₑ

    /C₀

    Time, min.

    H=25 cm

    H=20 cm

    H=15 cm

    H=10 cm

    H=5 cm

    0

    0.01

    0.02

    0.03

    0.04

    0.05

    0.06

    0.07

    0 5 10 15 20 25 30

    Ad

    orp

    tio

    n c

    apac

    ity,

    mg/

    g.

    Bed depth, cm.

  • Prof. Dr. Alaa Hussein Al-Fatlawi and Mena Muwafaq Neamah

    http://www.iaeme.com/IJCIET/index.asp 18 [email protected]

    (DWTS) particles represent dead zones because they don’t contribute in the

    adsorption process. So, adding a specific ratio of (RM) to the bed with a smaller

    particle size fills the dead zones between the particles and increases the total specific

    surface area of the bed leading an increase in the adsorption capacity and the

    operating time.

    Increasing the (RM) ratio to 50% caused the operating time to decrease as

    compared to 33% ratio, but the bed was still achieving slightly higher operating time

    and removal efficiency than the pure (0% ratio) (DWTS) bed. In fact, the (RM) has

    higher adsorption capacity and higher porosity than (DWTS). Therefore; increasing

    the (RM) ratio to 50% causes an increase in the available adsorption sites and the total

    adsorption capacity of the bed, and this leads to a decrease in the operating time.

    Figure.9 Experimental breakthrough curves for adsorption of phosphate onto different (RM)

    ratios, (C₀ =4 mg/L, pH=4, H=25 cm, Temp=25 ⁰C).

    6. CONCLUSIONS

    The following Conclusions were obtain from this study:-

    (DWTS) seems suitable for use as filler for remediation of wastewater contaminated by phosphate. The laboratory column experiment show the

    possibility decrease of contaminants in treated wastewater.

    The use of (DWTS) as a reactive medium for the treatment of wastewater ensures that significant rates of reduction of phosphate are achieved, particularly in cases

    in which there is initially a high concentration.

    Results from the column study showed that higher initial concentration resulted in shorter column saturation.

    (DWTS) is environment friendly, cost- effective, and locally available adsorbent for the adsorption of phosphate ions from secondary wastewater effluents.

    The effect of different (DWTS) – (RM) weight ratios shows that a significant decrease in the operating time is achieved by adding different ratios of (RM) to

    (DWTS). Adding 33 %, and 50 % (RM) weight ratios to the (DWTS) bed

    decreases the operating time by about 18%, and 30% respectively. Increasing the

    (RM) ratio to 50% caused the operating time to decrease as compared to 33%

    ratio.

    Increasing (RM) ratio increasing the removal efficiency and decreasing the equilibrium time in about 57% and 38% for 50% and 33% (RM) ratio

    respectively.

    0

    0.2

    0.4

    0.6

    0.8

    1

    1.2

    0 1000 2000 3000 4000

    Cₑ/

    C₀

    Time, min.

    DWTS

    33% RM

    50% RM

  • Column Study of The Adsorption of Phosphate by Using Drinking Water Treatment Sludge

    and Red Mud

    http://www.iaeme.com/IJCIET/index.asp 19 [email protected]

    One of the important aspects of the present study is represented by considering the (DWTS) as reactive medium, i.e. not inert. The utilization of these conditions

    is logic because the (DWTS) and (RM) may be worked together under the same

    field conditions of the continuous flow.

    REFERENCES

    [1] Almuamirah wastewater treatment plant, 2014.

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