Development of Integrated Filtration System Development of Integrated Filtration System for Water Treatment and Wastewater Reclamation for Water Treatment and Wastewater Reclamation

in Developing Countries in Developing Countries

C. ChiemchaisriC. Chiemchaisri

Department of Environmental Engineering Faculty of Engineering, Kasetsart University,

Bangkok 10900, Thailand

Introduction

-- Bangkok, like other mega cities in developingBangkok, like other mega cities in developingcountries, is suffering from the shortage of countries, is suffering from the shortage of water resources due to the deterioration of water resources due to the deterioration of natural water qualities.natural water qualities.

-- To overcome these problems, efficient water To overcome these problems, efficient water treatment systems for producing good quality treatment systems for producing good quality water supply and treated wastewater for water supply and treated wastewater for reuse are needed.reuse are needed.

-- Integrated filtration system employing floatingIntegrated filtration system employing floatingmedia filter coupled with conventional sand/media filter coupled with conventional sand/zeolite filter or membrane filtration was zeolite filter or membrane filtration was developed for water treatment and developed for water treatment and wastewater reclamation purposes.wastewater reclamation purposes.

-- Filtration is an essential unit for solid separation in convenFiltration is an essential unit for solid separation in conventional tional water treatment and tertiary wastewater treatment processes. water treatment and tertiary wastewater treatment processes.

-- Its applications include direct filtration of low turbidity waIts applications include direct filtration of low turbidity water or ter or filtration of coagulated water for high turbidity water. filtration of coagulated water for high turbidity water.

-- In this study, floating media filtration system coupled with cIn this study, floating media filtration system coupled with coarse oarse sand filter/ zeolite bed/ microfiltration membrane was appliesand filter/ zeolite bed/ microfiltration membrane was applied to the d to the treatment of surface water and secondary effluent. treatment of surface water and secondary effluent.

-- The advantages of system include smaller footprint comparingThe advantages of system include smaller footprint comparingto conventional water treatment processes, high treatment to conventional water treatment processes, high treatment efficiency and low operating cost.efficiency and low operating cost.

Integrated Filtration SystemIntegrated Filtration System

Floating media filter coupled with coarse sand filter or zeoliteFloating media filter coupled with coarse sand filter or zeolite bed bed for surface water treatment and wastewater reclamation for surface water treatment and wastewater reclamation

Floating media filter coupled with microfiltration membraneFloating media filter coupled with microfiltration membranefor surface water treatment for surface water treatment

Laboratory scale experimental unit Laboratory scale experimental unit

Polypropylene beadPolypropylene bead

Hollow fiber membrane moduleHollow fiber membrane module

Floating media filterFloating media filter Microfiltration membrane unitMicrofiltration membrane unit

Pilot scale testing at Bangkhen water treatment plantPilot scale testing at Bangkhen water treatment plant

Research series on Integrated Filtration SystemResearch series on Integrated Filtration System

1.1. Floating media/coarse sand filter for surface water treatmenFloating media/coarse sand filter for surface water treatment t (lab scale) (lab scale) -- turbidity removalturbidity removal

2. Floating media filter coupled/zeolite bed for wastewater 2. Floating media filter coupled/zeolite bed for wastewater reclamation (lab scale) reclamation (lab scale) -- turbidity, N, P removalsturbidity, N, P removals

3.3. Floating media filter/MF membrane for surface water treatmenFloating media filter/MF membrane for surface water treatment t (lab scale) (lab scale) -- turbidity, NOM, microorganism removals turbidity, NOM, microorganism removals

4.4. Floating media filter/MF membrane for surface water treatmenFloating media filter/MF membrane for surface water treatmentt(pilot scale) (pilot scale) -- turbidity, NOM removalsturbidity, NOM removals

Floating media filter/coarse sand filter for Floating media filter/coarse sand filter for surface water treatmentsurface water treatment

-- Coagulants Coagulants Alum, FeClAlum, FeCl33, PACl, polymer, PACl, polymer-- Filtration ratesFiltration rates 5,8,12 m5,8,12 m33/m/m22.h.h-- Media depthMedia depth 60:20, 50:30, 40:40, 30:50, 20:60 cm60:20, 50:30, 40:40, 30:50, 20:60 cm

and 1.5 m of floating media filter aloneand 1.5 m of floating media filter alone

Key findingsKey findings

Appropriate filtration rate of the system was found to be 5 m3/m2.h,It was limited by the particle retention capacity of floating media filter and headloss development in coarse sand filter

When only floating media filter of 1.5 m was used, the filtration rate of 15 and 10 m3/m2.h could be maintained to obtain satisfied effluent turbidity level in long term operation.

0

20

40

60

80

100

120

0 2 4 6 8Filtration time (h)

Hea

dlos

s (D

FF) (

cm)

5m/h

8m/h

12m/h

0

20

40

60

80

100

120

140

0 2 4 6 8

Filtration time (h)

Hea

dlos

s (D

FF+C

SF) (

cm)

5 m/h

8 m/h

12 m/h

0

5

10

15

20

25

30

0 2 4 6 8

Filtration time (h)

Turb

idity

(DFF

) (N

TU)

5m/h8m/h12m/h

0.0

5.0

10.0

15.0

20.0

25.0

0 2 4 6 8Filtration time (h)

Turb

idity

(DFF

+CSF

) (N

TU)

5 m/h

8 m/h

12 m/h

Turbidity removal and headloss development: Effect of filtrationTurbidity removal and headloss development: Effect of filtration raterate

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

0 2 4 6 8Filtration time (h)

Turb

idity

(DFF

) (N

TU)

60:2050:3040:4030:5020:60

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

0 2 4 6 8Filtration time (h)

Turb

idity

(DFF

+CSF

) (N

TU)

60:2050:3040:4030:5020:60

0

10

20

30

40

50

60

70

80

0 2 4 6 8

Filtration time (h)

Hea

dlos

s (D

FF) (

cm)

60:2050:3040:4030:5020:60

0

10

20

30

40

50

60

70

80

0 2 4 6 8Filtration time (h)

Hea

dlos

s (D

FF+C

SF)

(cm

)

60:2050:3040:4030:5020:60

Turbidity removal and headloss development: Effect of bed depthTurbidity removal and headloss development: Effect of bed depth

45

50

55

60

65

70

75

80

85

90

95

100

0 25 50 75 100 125 150 175 200 225 250 275 300

bed depth:media size(L/d)

Turb

idity

rem

oval

(%)

3 mm

6 mm

8 mm

Relationship between L/d and turbidity removal in plastic media pre-filter

Floating media filter/ zeolite bed for Floating media filter/ zeolite bed for wastewater reclamationwastewater reclamation

-- Direction filtration of secondary effluent from sewage treatmentDirection filtration of secondary effluent from sewage treatmentplant (particle removal)plant (particle removal)

-- Chemical precipitation (for P removal) using FeClChemical precipitation (for P removal) using FeCl33 and zeolite bedand zeolite bed(for N removal)(for N removal)

-- Filtration ratesFiltration rates 1,3,5 m1,3,5 m33/m/m22.h.h-- Media depthMedia depth 40:40 cm40:40 cm

Key findingsKey findingsA filtration rate of 5 m3/m2.h was proposed for direct filtration mode (only turbidity removal) whereas 1 m3/m2.h was recommended for N, P removal from secondary effluent.

Treated water qualities for N, P removal and breakthrough periodTreated water qualities for N, P removal and breakthrough period

Parameters Std. Limit1(m3/m2.h) 3 (m3/m2.h) 5 (m3/m2.h)

Eff. Hours Eff. Hours Eff. Hours

SS (mg/l) < 5 0.4 >12 7.0 9 10.0 3

Turbidity (NTU) < 5 0.2 >12 4.7 10 46.5 3

NH4+ (mg N/l) <5 0.9 >12 5.6 9 2.1 3

PO43- (mg P/l) < 0.05 0.02 >12 0.13 8 1.18 3

Parameters InfluentEffluent

% RemovalRange Average

pH 7.3 5.6-6.4 6.0

SS (mg/l) 10.3 0-2.2 0.5 91.9

Turbidity (NTU)- DFF 6.8 0.1-1.5 0.7 90.0

Turbidity (NTU)- Overall 6.8 0.1-0.9 0.3 94.6

BOD (mg/l) 18.3 0.7-1.0 0.9 95.4

NH4+ (mg N/l) 22.5 0-7.0 0.5 97.8

PO43- (mg P/l) 4.41 0-0.06 0.02 99.5

Floating Media Filter Floating Media Filter -- Acrylic column of 10 cm. diameter and 180 cm. longAcrylic column of 10 cm. diameter and 180 cm. long-- Plastic media: Polypropylene (PP) bead of 3.6 mm diameterPlastic media: Polypropylene (PP) bead of 3.6 mm diameter1 m. bed depth1 m. bed depth

Microfiltration Membrane UnitMicrofiltration Membrane Unit-- Hollow filter membrane module with 0.1 Hollow filter membrane module with 0.1 μμm pore sizem pore sizeand 0.2 mand 0.2 m22 surface areasurface area

Filtration rateFiltration rate 5, 10, 15 m5, 10, 15 m33/m/m22.h.hCoagulantCoagulant Polyaluminum chloride (PACl)Polyaluminum chloride (PACl)

at 25%, 50% and 100% of jar testat 25%, 50% and 100% of jar test

Floating media filter/MF membrane forFloating media filter/MF membrane forSurface water treatmentSurface water treatment

Key findingsKey findings

Floating media filter was effective in promoting flocculation aFloating media filter was effective in promoting flocculation and removingnd removingsolid particles from raw watersolid particles from raw water

Low filtration rate (5 mLow filtration rate (5 m33/m/m22.h) was preferred to prevent breakthrough and .h) was preferred to prevent breakthrough and reduce the solid particle loading to MF membranereduce the solid particle loading to MF membrane

0102030405060708090

100

0 30 60 90 120 150 180 210 240 270 300 330 360

PACl 8 mg/lPACl 4 mg/lPACl 2 mg/l

Turb

idity

(NTU

)

Time(min)

V = 10 m/hr

0102030405060708090

100

0 30 60 90 120 150 180 210 240 270 300 330 360

PACl 8 mg/lPACl 4 mg/lPACl 2 mg/l

Turb

idity

(NTU

)

Time(min)

V = 15 m/hr

0102030405060708090

100

0 30 60 90 120 150 180 210 240 270 300 330 360

PACl 8 mg/lPACl 4 mg/lPACl 2 mg/l

Turb

idity

(N

TU)

Time(min)

V = 5 m/hr

Particle removal in floating media filterParticle removal in floating media filter(RW turbidity 80 NTU)(RW turbidity 80 NTU)

Opt. dose 100%

Opt. doseOpt. dose 50%50% Breakthrough of particles

0200400600800

100012001400160018002000

0.00 0.20 0.50 0.70 1.00 1.30 1.60

120 min 240 min 360 minSS

(mg/

l)

Depth(m)

V = 5 m/hr

PACl 8 mg/l

0

50

100

150

200

0.00 0.20 0.50 0.70 1.00 1.30 1.60

120 min 240 min 360 min

Floc

Siz

e(um

)

Depth(m)

V = 5 m/hr

PACl 8 mg/l

Accumulation of solid particlesIn floating media filter

0

2000

4000

6000

8000

10000

0.00 0.20 0.50 0.70 1.00 1.30 1.60

120 min 240 min 360 min

SS(m

g/l)

Depth(m)

V = 10 m/hr

PACl 4 mg/l

0

100

200

300

400

0.00 0.20 0.50 0.70 1.00 1.30 1.60

120 min 240 min 360 min

Floc

Siz

e(um

)

Depth(m)

V = 10 m/hr

PACl 4 mg/l

Release of small particles from floating filter

Deeper accumulationIn the filter bed

02468

101214161820

0 10 20 30 40 50 60 70 80

80 NTU

Tran

smem

bran

e P

ress

ure(

kPa)

V=0.6 m/d V=1.0 m/d V=1.4 m/d V=5 m/hr V=10 m/hr

Turbidity(NTU)

Effect of turbidity and particle size on Effect of turbidity and particle size on transmembranetransmembrane pressurepressuredevelopment of MF membrane development of MF membrane

DFF+MF

MF 0

5

10

15

20

0 10 20 30 40 50 60 70 80 90 100

Tran

smem

bran

e P

ress

ure(

kPa)

80 NTU

V=0.6 m/d V=1.0 m/d V=1.4 m/d V=5 m/hr V=10 m/hr

Floc Size(um)

DFF+MF

MF

MF membrane removed the remaining turbidity in water yielding cMF membrane removed the remaining turbidity in water yielding constantonstanteffluent turbidity. effluent turbidity. TransmembraneTransmembrane pressure development was low pressure development was low following the pretreatment by floating media filterfollowing the pretreatment by floating media filter

NOM removal in floating media filter/MF systemNOM removal in floating media filter/MF system

Key findingsKey findings

High degree of NOM removal (>85%) was achieved in the system.High degree of NOM removal (>85%) was achieved in the system.

Enhanced coagulation effect provided more than 80% of UVEnhanced coagulation effect provided more than 80% of UV254 254 removal removal in floating media filter.in floating media filter.

NOM removal results in significant reduction in chlorine demand NOM removal results in significant reduction in chlorine demand and and THM formation.THM formation.

Both turbidity and NOM concentration affected the fouling of memBoth turbidity and NOM concentration affected the fouling of membrane brane but TMP built up was mainly caused by particulate foulingbut TMP built up was mainly caused by particulate fouling

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30 35 40

Coagulant dose (mg/l)

UV

rem

oval

(%)

alum-medium turbidityPACl-medium turbidityFeCl3-medium turbidityalum-high turbidityPACl-high turbidityFeCl3-high turbidity

UVUV254254 removal during coagulation of river water removal during coagulation of river water

PACl was found to be the most PACl was found to be the most effective coagulant for NOM removal.effective coagulant for NOM removal.Optimum dose was 15Optimum dose was 15--25 mg/l giving 25 mg/l giving 7575--90% UV90% UV254254 removal.removal.

y = 0.7213xR2 = 0.95

y = 0.8969xR2 = 0.9578

0

20

40

60

80

100

0 20 40 60 80 100Turbidity removal (%)

UV

rem

oval

(%)

Relationship between turbidity Relationship between turbidity and UVand UV254254 removal in floating removal in floating media filtermedia filter

Turbidity and NOM removal in floating media filter/MF systemTurbidity and NOM removal in floating media filter/MF system

Condition Turbidity (NTU) UV254 (cm-1)

Avg. %Removal Avg. %Removal1. PACl 100%

1.1 PP (7.5 m/h)MF (0.3 m/d)

1.2 PP [11 m/h)MF (0.45 m/d)

2. PACl 50%2.1 PP (7.5 m/h)

MF (0.3 m/d)2.2 PP (11 m/h)

MF (0.45 m/d)

15.90.5318.80.55

85.599.583.899.5

0.1470.1020.1800.110

80.786.676.685.7

25.40.59

76.799.5

0.2000.120

72.683.6

17.20.61

78.799.2

0.1980.110

66.481.3

ParametersParameters ValueValue

RangeRange Avg.Avg.

pHpHTurbidity (NTU)Turbidity (NTU)UVUV254254 (cm(cm--11) ) DOC (mg/l)DOC (mg/l)Color (TCU)Color (TCU)

7.657.65--7.847.840.510.51--0.680.680.060.06--0.110.112.782.78--2.992.992.82.8--3.63.6

7.737.730.600.600.080.082.882.883.23.2

TMP development in MF TMP development in MF membrane unitmembrane unit

0

5

10

15

20

25

0 2 4 6 8 10 12 14 16 18 20 22 24

Time (hours)

TMP

(kPa

)

0.45 m/d-100%

0.3 m/d-100%

0.45 m/d-50%

0.3 m/d-50%

012

34567

89

10

T0.6 U0.05 T1.3 U0.30 T66 U0.60 T16 U0.16 T66 U0.30 T16 U0.30

Raw water qualities

TMP

incr

ease

(kPa

)

Effect of raw water qualitiesEffect of raw water qualities(Turbidity and UV(Turbidity and UV254254))on TMP development on TMP development

Reduction in ClReduction in Cl22 demand and THM formationdemand and THM formation

SampleSample ClCl22 dosedose(mg/l)(mg/l)

CHLOCHLO((μμg/lg/l))

DCBMDCBM((μμg/lg/l))

DBCM DBCM ((μμg/lg/l))

Sum of THM Sum of THM ratioratio

RWRW 2.02.02.52.5

7171138138

6699

0.450.450.440.44

0.50.50.80.8

3.03.03.53.55.05.0

129129145145175175

9999

1111

0.470.470.540.540.550.55

0.80.80.90.91.1

TWTW 2.02.02.52.53.03.03.53.55.05.0

33334646676773738686

4466888899

0.380.380.590.590.700.700.740.740.760.76

0.20.20.30.30.50.50.50.50.60.6

0.5 to 1.0 mg/l reduction in chlorine demand was achieved after 0.5 to 1.0 mg/l reduction in chlorine demand was achieved after removing removing NOM from the water. THM formation was reduced by 40NOM from the water. THM formation was reduced by 40--60%60%

Sum of THM = CSum of THM = CCHLOCHLO/GV/GVCHLOCHLO + C+ CDCBMDCBM/GV/GVDCBMDCBM + C+ CDBCMDBCM/GV/GVDBCMDBCM + C+ CBROMOBROMO/GV/GVBROMOBROMO < 1< 1(WHO guideline) (WHO guideline)

Water borne microorganism removal by floating media Water borne microorganism removal by floating media filter/MF membranefilter/MF membrane

Key findingsKey findings

Freshwater algae was found partially removed by coagulation and Freshwater algae was found partially removed by coagulation and entrappedentrappedin floating media filter but completely retained by MF membin floating media filter but completely retained by MF membranerane

Total coliform and Fecal coliform was effectively removed by cTotal coliform and Fecal coliform was effectively removed by coagulation and oagulation and retained in floating media filter at low filtration rate (5retained in floating media filter at low filtration rate (5 m/h)m/h)

At higher filtration rate, total and fecal coliform removal efAt higher filtration rate, total and fecal coliform removal efficiencies were ficiencies were significantly reduced. Nevertheless, MF membrane helped remsignificantly reduced. Nevertheless, MF membrane helped removing theoving theremaining TC and FC from waterremaining TC and FC from water

Coliphage was removed better in floating media filter operatedColiphage was removed better in floating media filter operated at higher at higher filtration rate but poorly retained by MF. filtration rate but poorly retained by MF.

1

10

100

1000

10000

0 2 4 6 8

Operation Time (Hour)

Mic

roor

gani

sms

(x10

4 MPN

/100

ml,

PFU

/ml)

0

20

40

60

80

100

120

140

Turbidity (NTU

)

(a)

1

10

100

1000

10000

0 2 4 6 8

Operation Time (Hour)

Mic

roor

gani

sms

(MPN

/100

ml,

PFU

/ml)

0

10

20

30

40

50

60

70

Turbidity (NTU

)

TC FCCP NTU

(b)

penetration of CP Through MF

1

10

100

1000

10000

0 1 2 3 4 5 6

Mic

roor

gani

sms

(MPN

/100

ml,

PFU

/ml)

TCFCCP

No coagulant: 5 m/h

1

10

100

1000

10000

0 1 2 3 4 5 6

Operation Time (Hour)

Mic

roor

gani

sms

(MPN

/100

ml,

PFU

/ml)

with coagulant:5 m/h

1

10

100

1000

10000

0 1 2 3 4 5 6

No coagulant:15 m/h

improved CP removal

Improved FC removal

Floating filter

MF

Floating filter

Future research needsFuture research needs& possible collaboration& possible collaboration

-- Investigation of trace pollutants (e.g. pesticide, pharmaceutiInvestigation of trace pollutants (e.g. pesticide, pharmaceuticals) cals) contamination in surface water/treated wastewater in floatingcontamination in surface water/treated wastewater in floating media media and membrane filtration system and membrane filtration system

-- Enhancement of NOM removal by floating media bioEnhancement of NOM removal by floating media bio--filtration filtration or photoor photo--oxidation associated with MF membrane for polluted water oxidation associated with MF membrane for polluted water treatmenttreatment

-- Detailed investigation of microorganism removal in floating Detailed investigation of microorganism removal in floating media filter coupled with MF membrane treating actual river wmedia filter coupled with MF membrane treating actual river water. ater.

-- Implementation of full scale integrated filtration system at BImplementation of full scale integrated filtration system at Bangkokangkokwaterworks and sewage treatment plantswaterworks and sewage treatment plants

Other research collaborationsOther research collaborations

-- Development of photosynthetic bacteria pond system for carbonDevelopment of photosynthetic bacteria pond system for carbonrecovery from industrial wastewater (with UT)recovery from industrial wastewater (with UT)

-- Investigation of reverse osmosis (RO) membrane fouling during Investigation of reverse osmosis (RO) membrane fouling during reclamation of textile wastewater (WRPC & UT)reclamation of textile wastewater (WRPC & UT)

-- Application of membrane bioreactor (MBR) and RO system to soliApplication of membrane bioreactor (MBR) and RO system to solid d waste leachate treatment (UT)waste leachate treatment (UT)

Full scale application of advanced leachate treatment system Full scale application of advanced leachate treatment system (1000 m(1000 m33/d) in Thailand/d) in Thailand