Ibnu Samsi & Yu

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Effect of Water Quality Improvement

in Raw Water Source on WaterTreatment Cost: A Case Study of

West Tarum Canal in Java

Aug 22, 2011

Ibnu Samsi, Myong Jin Yu

UNIVERSITY OF SEOUL


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UNIVERSITY OF SEOUL


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UNIVERSITY OF SEOUL

WTC System and Water Quality Monitoring Points


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UNIVERSITY OF SEOUL


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UNIVERSITY OF SEOUL

West Tarum Canal (WTC)Cibeet, Cikarang and Bekasi River intercepted by WTC.Erosion by deforestration, and discharge of untreated domestic andindustrial wastewater in the basins of three rivers.Deterioration of WTC water quality.

Water Uses of WTCRaw water supply to Water Treatment Plants (16.3m3/sec to Jakarta)IrrigationIndustrial Uses

River Water Classification CLASS I(Gov. Regulation No. 82/2001 concerning water quality management)

Present Water Quality of WTCOut of Class IV based on some parameters, BOD, DO, COD, SS,Fecal Coliform

Introduction


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UNIVERSITY OF SEOUL

Parameters Units CLASS I CLASS IV

Temperature C Dev. 3 Dev. 5

TDS mg/L 1000 2000

SS mg/L 50 400

Turbidity NTU -

pH mg/L 6-9 5-9

BOD mg/L 2 12

COD mg/L 10 100

DO mg/L 6 0NH3-N mg/L 0.5 -

NO3-N mg/L 10 20

Fe mg/L 0.3 -

Mn mg/L 0.1 -

Key Water Parameters for WTC


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UNIVERSITY OF SEOUL

Turbidity

The most important quality parameter affecting coagulant dose in water

treatment

WHO sets maximum level 5 NTU, 1 NTU for successful disinfection

Less than 0.1 NTU applied to filtered water for removal of Giardia andCryptosporidium

Raw water turbidity ranged from 3 to 28,239 NTU at Buaran WTP

which takes raw water downstream of WTC


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UNIVERSITY OF SEOUL

Water Quality Levels at WTC and Crossing Rivers

100908070605040302010099989796959493

30

25

20

15

10

5

0

Year

B

O

D

m

g

/

L

1 Curug

11 Cibeet

12 Cikarang13 Bekasi

9 BTb.51

BOD5levels at the West Tarum Canal and crossing riversduring the period 1993-2010


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UNIVERSITY OF SEOUL

Turbidity levels at the West Tarum Canal and crossing riversduring the period 1993-2010

100908070605040302010099989796959493

16000

14000

12000

10000

8000

6000

4000

2000

0

Year

T

u

r

b

i

d

i

y

N

T

U

1 Curug

11 Cibeet

12 Cikarng

13 Bekasi

9 BTb.51


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UNIVERSITY OF SEOUL

Raw water turbidity

20000100006000300010005001005010

160

140

120

100

80

60

40

20

0

Turbidity NTU

F

e

q

u

e

n

c

y

000000229

1817

2932

282323

3334

28

34

42

80

115117122122

148141

118

78

110

129

101

57

26

100000

Daily average

3000020000100006000300010005001005010

140

120

100

80

60

40

20

0

T u r b i d i t y NT U

r

e

q

u

e

n

y

113

17

29

37

1617

24

30

16

292526

36

2024

34

53

7574

106

80

112

98

123

135

109

86

107109

90

64

11

1100000

Dai ly max imum

20000100006000300010005001005010

200

150

100

50

0

Turbidity NTU

F

e

q

u

e

n

c

y

0000000000011341

101322

28

4441

60

81

127

153

180

157

171

130

116

102

167

6876

58

13001

Daily minimum

Raw water turbidity frequencies atBuaran WTP

during the period 2006-2010


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UNIVERSITY OF SEOUL

Yearly frequencies of raw water turbidity at Buaran WTP

Turbidity, NTUFrequency of

daily average

Frequency of

daily maximum

0 ~ 300 298 253

300 ~ 1000 32 47

1000 ~3000 27 27

3000 ~ 10000 8 23

10000 ~ 14


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UNIVERSITY OF SEOUL

BOD5and turbidity along WTC will be comparedin the following conditions.

Present

After Bekasi siphon constructionAfter Bekasi and Cikarang siphon constructionAfter Bekasi and Cibeet siphon constructionAfter Bekasi, Cikarang and Cibeet siphon construction

Results and discussion

Effects of separation of three rivers on water quality of WTC

Bekasi siphon most effective in reducing both BOD5and turbidityCikarang siphon more effective in BOD5 reduction.Cibeet siphon more effective in turbidity reduction.


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UNIVERSITY OF SEOUL

Effects of siphons on water qualities at the Buaran WTP intakeusing water quality data during the period 1993-2010

Alternatives

BOD

at Buaran(mg/L)

BOD

reduction(%)

Turbidity

at Buaran(NTU)

Turbidity

reduction(%)

Present 8.22 822.9

Bekasi siphon 6.53 20.5 624.7 24.1

Bekasi &

Cikarang siphon5.70 30.7 504.4 38.7

Bekasi & Cibeet

siphon 6.2 25.0 455.3 44.7

Bekasi, Cikarang

& Cibeet siphon5.26 36.0 304.5 63.0


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UNIVERSITY OF SEOUL

Turbidity frequency change at Buaran WTPafter the construction of siphons

Turbidity

range, NTU

Present

frequency

Frequency

after Bekasi

siphon

Frequency

after Bekasi

&Cikarang

siphon

Frequency

after Bekasi

&Cibeet

siphon

Frequency

after Bekasi,

Cikarang &

Cibeet siphon

0 ~ 300 298 314 324 328 340

300 ~ 1000 32 24 20 18 15

1000 ~3000 27 20 17 15 10

3000 ~ 10000 8 6 5 4 0

Improvement of raw water turbidity by separation of three rivers


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UNIVERSITY OF SEOUL

Chemicals used for turbidity removal

Chemicals used at the Buaran WTP

Chemical Component Use Unit price

Alum (Liquid) Aluminum sulphate Coagulation $200-400 per ton

PAC Polyaluminium chloride Coagulation $300-320 per ton

Sudfloc A Aluminum chlorohydrate Coagulation $750-800 per tonLT20 Polyacrylamide Coagulation aid $4.99 per kg

LT7994Polydiallyldimethylammonium Chloride

Coagulation aid $4.99 per kg

Lime Calcium hydroxide pH adjustment $90-200 per ton

Chlorine Liquid chlorine Disinfection $100-300 per ton

Daily average, maximum and minimum turbidity.Chemical doses such as alum, PAC, Sudfloc A, LT 20,LT7994, lime and chlorine every two hours.

S O S O


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Relation between daily average turbidityremoved and chemicals used

In general one kind of coagulant such as Alum or PAC is used inmoderately turbid raw water.Extremely high turbidity in high frequency makes purificationprocesses extremely difficult.Therefore, combination of three kinds of coagulant is used tostrengthen the effects of each ones, and either of two kinds of

polyelectrolyte is applied to make dense floc.Turbidity removal was related to the combined action of Alum, PAC,Sudofloc A and polyelectrolytes as follows:

Average turbidity = - 411 + 2.65 Alum + 0.67 PAC + 12.4 Sudofloc A+ 1919 Total polymer

The R2measure for the model is 0.617.

UNIVERSITY OF SEOUL


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UNIVERSITY OF SEOUL

Water treatment cost saving by separation of three rivers

An empirical approach was tried to develop a model that relates chemicalcost per unit of treated water to raw water quality.Water quality parameters such as turbidity, pH, organic matter and colorof raw water which are available and considered to influence coagulationprocess were included in regression equations.

Costs/1000m3

for all the chemicals was related to the raw water turbiditywith R2 of 0.197 as follows.

Cost/1000m3= 23.2 + 0.00464 Daily average turbidity

The R

2

was not increased much more by including more parameters.

UNIVERSITY OF SEOUL


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UNIVERSITY OF SEOUL

Chemical cost reductions at the water treatment plants using raw waterfrom WTC for water quality management alternatives (in US $)

Yearly chemical cost Yearly chemical cost reduction byapplying alternatives

Alternatives Buaran WTPAll the WTPs using

WTC raw waterBuaran WTP

All the WTPs using

WTC raw water

Present 4,402,139 13,686,650

Bekasi siphon 4,340,099 13,493,763 62,040 192,886

Bekasi &

Cikarang siphon4,302,515 13,376,911 99,624 309,739

Bekasi & Cibeetsiphon 4,287,070 13,328,889 115,069 357,760

Bekasi, Cikarang

& Cibeet siphon4,202,042 13,064,529 200,097 622,120

UNIVERSITY OF SEOUL


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UNIVERSITY OF SEOUL

Conclusions

Water quality improvement in terms of turbidity and BOD in thedownstream of WTC was evaluated with application of alternatives insiphon constructions.Then yearly savings in chemicals cost were derived applying chemicalcost per unit of water treated estimated in the wide range of raw waterturbidity at Buaran WTP.

These savings in chemicals would be only part of cost savings in watertreatment. Other savings in labor, electricity and maintenance from less useof chemicals and disposal of less sludge should be included for completeanalysis.There is difficulty in assessing management alternatives by only limited

general water quality parameters such as BOD and turbidity which comefrom organic pollution and sediment. Load assessment for industrialsources will be necessary in crossing river basins to know the possibility inrelease of harmful pollutants into the raw water to WTPs.

UNIVERSITY OF SEOUL


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UNIVERSITY OF SEOUL

Ibnu Samsi & Yu

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