priority organic pollutants associated with wastewater reuse in soil irrigation in Kuwait

e>

Pergamon

Wal. Sci. T~ch. Vol. 40, No.7, pp. 1-10, 1999

OI999IAWQ

pn: 50273-1223(99)00577-6

Published by Elsevier Scien<:e Ltd PrinlM in Greal Britain. All nghts reserved 0273-1223/99 $20.00 + 0.00

FATE OF CONVENTIONAUPRIORITY ORGANIC POLLUTANTS ASSOCIATED WITH WASTEWATER REUSE IN SOIL IRRIGATION IN KUWAIT Saleh AI-Muzaini and Ahmad A. Ghosn Environmental Sciences Department, Kuwait Institute for Scientific Research, P. O. BoJC 24885, Safat 13109, Kuwait

ABSTRACT Soil contamination from conventional/priority organic pollutants associated the reuse of wastewater for agricultural irrigation in selected sites in Kuwait is assessed in this paper using a laboratory pilot plant designed for this purpose. The permeated wastewaters included industrial and tertiary treated wastewaters from different industrial and wastewater treatment plants in Kuwait Tab (potable) water will be also used as a reference base. The investigated soil sites covered representative agricultural areas in Kuwait including AI-Wafra, AI• AbdaUy and Sulaibiya agricultural sites. The soil characteristics in these sites are presented. The preliminary results of pilot plant tests for Abdally area soils are discussed herein and related conclusions and remarks are outlined. 0 1999 IAWQ Published by Elsevier Science Ltd. AIl rights reserved.

KEYWORDS

Soil contamination; Wafra; Abdally; Sulaibiya; Agricultural sites; Kuwait. INTRODUCTION Kuwait is an arid country. Hence, water resources are very scarce and water is a valuable commodity. Due to the fast-paced development in Kuwait over the last two decades, demand on water supply has increased significantly. To respond to the emerging demands for water the Kuwaiti government has set plans to utilize industrial and municipal wastewater for potential reuse in various applications (e.g. agriculture, landscaping, afforestation, etc.). Such plans. if successfully implemented, could significantly reduce the environmental impacts of discharging wastewater into the sea and could as well convert treated wastewater into a new source of water supply. Over the past few years, many of the government plans have been put into practice and treated wastewater has been successfully used for agricultural applications. This paper addresses the potential environmental impacts of reusing treated wastewater for agricultural applications. It is derived from a currently on-going project at the Kuwait Institute for Scientific Research (KlSR) entitled "Fate of ConvenlionaV Priority Organic Pollutants of Wastewater in Soil".

2

S. AL-MUZAINI and A. A. GHOSN

ASSESSMENT OF RECLAIMED WASTEWATERS SOURCES IN KUWAIT Major sources of reclaimed sewage wastewater Table 1 presents the available information about the operational characteristics and sewage flow forecasts for the main treatment plants in Kuwait as obtained from recent studies at KlSR (Ghobrial et al., 1987). Sewage inflow rates in this table are predicted based on expected increases in catchment population and on overall per capita sewage contribution (165-190 litre/day). Table 1. Operational characteristics and sewage flow forecasts for Kuwait's treatment plants (Ghobrial et al., 1987) Plant

Treatment Process

Data Commissioned

DeSign capacity 3

(m /d)

Ardhiya

Jahra

Reqqa

Two-stage Aeration Activated Sludge; Sand Drying Beds; Tertiary Treatment with Pre- and Post chlorination Extended Aeration Activated Sludge; Sand Drying Beds; Tertiary Treatment with Pre- and Post Chlorination Extended Aeration Activated Sludge; Sand Drying Beds; Tertiary Treatment with Pre- and Post Chlorination

Sewage inflow

Catchment Population (millions

(m3/d)

1990

2020

1990

2020

1971

150,000

1.16

1.19

192,000

225,000

1981

70,000

0.19

0.39

32,000

73,000

1981

100,000

0.36

0.88

58,000

166,000

Characteristics of raw domestic sewage effiuents Available information indicates that domestic raw sewage in Kuwait has high strength and is rather septic. This is mainly attributed to low flow rates induced by sand accumulation in sewer systems, high ambient temperature, concomitant anaerobicity and long retention time (Ghobrial et al., 1987, Al-Muzaini et al., 1991). Domestic raw sewage effluents in Kuwait are also characterized by their high organic contents compared with other Gulf countries (ROPME, 1986). They may as well contain toxic contaminants such as oil, heavy metals, polychlorinated biphenyls and chlorinated pesticides (Ghobrial et a/1987, Samham and Ghobrial, 1987). Table 2 summarizes the local sewage characteristics in Kuwait and in the Gulfregion.

3

Fate of conventional/priority organic pollutants

Characteristics of tertiary treated effluents in main sewage treatment plants The physical properties of treated effluents in the main treatment plants in Kuwait are presented in Table 3 and the chemical properties are shown in Table 4. For the purpose of this study, only tertiary effluents with alarming organic! priority pollutant levels will be investigated. Industrial wastewater sources Investigations were conducted to determine current flows for both industrial wastewater and sanitary wastewater in Shuaiba Industrial Area (SIA) and related future projections were made (SAA-1990). The projected sanitary wastewater flow based on the ultimate development of the SIA was estimated at about 5000 m3/day versus current flow rate of about 3000 m 3/day. Industrial wastewater generated by the four main industries is estimated at 31000 m3/d. With the addition of the KPC - Petrochemical Complex and other future projects and long term development at SIA, the predicted industrial wastewater flow will reach about 51,000 m 3/d. Table 5 presents the projected flow rates in SIA. The projected characteristics of industrial wastewater within SIA and MAlA are also presented in Table 6. As indicated in this table, the wastewater generated in MAlA contains only suspended solids and some organic and inorganic contaminants as indicated by COD values. Table 2. Local sewage characteristics in Kuwait (Ghobrial et al., 1987) Measured Parameter

Concentration range in Kuwait (mgfl)

Concentration range in the Gulf(mgfl)

BOD COD TSS

300-550 480-1250 75-650 44-100 50-140 14-64 15-135 210-440 ND-47

180-420 330-390 165-400 20-45 22 38-50

NH)-N

TOTALN PO.-P Grease/Oil TOC Sulfides

NM NM NM

Typical Values for Sewage 400 1000 350

SO

85 10 150 290 NM

220 500 220 25 40 5 100

160 NM

110

250

110

12 20 3 50 80 NM

ND: not determined; NM: not measured ASSESSMENT OF SOn.. CHRACTERISTICS IN KUWAIT Available literature about the soils of Kuwait indicate that they have been formed under arid conditions and are dominantly characterized by the presence of calciferous and/or gypsiferious hardpan layers, locally known as "gatch" which vary in composition, thickness, degree of cementation and depth. While in the northern and western areas of Kuwait they could be encountered at depths of 0·0.75 metres with an enriched gravel content and presence of "gatch" at or near the surface, they could be as deep as two metres in the southern and southeastern areas of the country. Kuwait has not been covered by any comprehensive systematic soil survey. Scattered information was cited in a few available service reports, of which Ergun's (Ergun, 1969) is the most comprehensive. Ergun classified Kuwaiti soils into four main groups and several soil types as presented in Table 7.

.... Table 3. Physical characteristics of tertiary effiuents in Kuwait (MPW, 1996)

REGA COD BOD

pH

TSS

VSS

mgll

mg/l

mg/l

mg/l

6.8 7.0 7.0 7.0 7.0 7.1 7.2

1.9 3.8 3.9 3.1 2.2 4.6 3.2 NM NM NM

1.3 ND 25 2.5 1.8 36 24

34.0 33.0 31.0 31.0 25.0 30.0 32.0

NM

NM

NM NM

NM NM NM 7.0 7.2 6.8 ND:

JAHRA COD

F.CI

pH

TSS

VSS

mg/l

mg/l

mg/l

mg/l

mg/l

4.0 4.5 3.5 3.5 2.4 5.2 3.2

0.8 0.7 0.7 0.7 0.8 0.8 0.8

7.3 7.6 7.5 7.5 7.4 7.4 7.5 7.4 7.4 7.3 7.0 7.1 7.4 7.6 7.0

9.1 54.3 22.6 8.1 7.8 52 3.3 5.4 5.7 4.4 3.7 3.7 11.1 54.3 3.3

7.2 45.7 17.8 6.1 5.9 3.9 2.3 4.1 4.3 3.9 2.8 2.8 8.8 45.7 2.3

-NM

NM

NM NM NM NM NM NM NM NM NM NM NM NM NM NM NM NM NM NM 3.2 2.4 30.0 3.8 0.8 4.6 34.0 5.2 3.6 0.8 25.0 2.4 0.7 1.9 1.3 not determined; NM: not measured

ARDIYA COD

BOD F.CI

pH

TSS

VSS

mg/l

mg/l

mg/l

mg/l

mg/l

mg/l

mg/l

mgll

mg/l

53.3 154.5 98.3 47.3 36.9 26.4 24.7 31.7 28.9 25.1 20.9 19.5 47.3 154.5 19.5

8.7 19.4 22.1 9.3 7.0 5.3 4.0 5.8 5.4 4.4 3.7 3.5 8.2 22.1 3.5

0.5 0.5 0.5 0.8 0.8 0.8 0.9 0.7 1.5 1.6 1.2 0.7 0.9 1.6 0.5

7.2 7.2 7.4 7.3 7.4 7.4 7.5 7.4 7.6 7.6 7.7 7.7 7.5 7.7 7.2

5.1 5.2 5.4 4.1 3.1 5.3 4.7 4.1 7.6 3.7 7.5 6.6 5.2 7.6 7.1

3.7 3.8 4.1 2.9 2.2 3.7 3.1 4.3 6 2.8 6.6 5.8 4.1 6.6 2.2

38.0 38.0 37.0 44.0 41.0 41.0 41.0 42.0 46.3 38.4 52.0 45.8 42.0 52.0 37.0

9.0 10.0 10.0 9.0 8.0 8.0 7.0 8.0 6.4 3.9 4.0 4.5 7.0 10.0 4.0

ND ND ND ND 2.9 2.9 4.4 4.3 1.8 34 3.3 3.3 2.2 4.4 1.8

BOD F.CI

rn

~

I 8-

il> ?>

~ ~

Fate of conventional/priority organic pollutants

5

Table 4. Chemical characteristics oftreated effluents (MPW 1996) Plant

NH3 mg/I

Cd mg/I

Cr mg/I

Cu mg/I

Pb mg/I

Hg mg/l

Ni mg/l

Avg. Max. Min. Jahra

10.7 18.6 3.9

0.0003 0.0005 0.0001

0.0038 0.0089 0.0010

0.0032 0.0062 0.0014

0.0061 0.0242 0.0020

0.0015 0.0026 0.0011

0.0213 0.0284 0.0127

Avg. Max. Min.

11.9 37.6 0.3

0.0016 0.0034 0.0006

0.0069 0.0099 0.0036

0.0085 0.0155 0.0046

0.0133 0.0371 0.0040

0.0015 0.0027 0.0009

0.0300 0.0960 0.0415

Regga

Table 5. Projected flow rates of wastewater in Shuaiba Industrial Area (SIA) Wastewater Source/Location Mina AI-Ahmadi Refinery and LPG Plant Mina Abdulla Refmery Shuaiba Refinery PIC Fertilizer and Polypropylene Plants KPC Petrochemicals Complex KNPC Petrochemicals complex

8,360 6,910 8,400 4,940 15,000 7,000

INDUSTRIAL WASTEWATER FLOW (FOR DESIGN) INDUSTRIAL WASTEWATER FLOW (ULTIMATE) SIA Eastern Sector Sanitary SIA Western Sector Sanitary SANITARY WASTEWATER FLOW (ULTIMATEIDESIGN) COMBINED TOTAL WASTEWATER FLOW (ULTIMATE)

44,610 50,610 2,480 2.580 5,060 55,670

LPG: Liquefied Petroleum Gas, PIC: Petrochemical industries company, KPC: Kuwait Petroleum Company KNPC: Kuwait National Petroleum Company Generally speaking, soils of Kuwait are invariably calcareous due to arid climate and high content oflime in the soil parent materials. The country also falls in the shadow of dust storms that originate in desert regions of Iraq, Jordan and Syria. These storms contribute significant amounts of calcareous dust to the soils. The Low content of organic matter and high content oflime in these soils render their surface loose and unstable and thus highly vulnerable to wind and water erosion. The soil samples tested in this study covered three agricultural areas in Kuwait including Abdally, Sulaibiya and Wafra. The grain size analysis and physical properties of these samples are presented in Tables 8 and 9, respectively. The grain size analysis indicated that all soils are loamy sand as per USDA classification.

6

S. AL·MUZAINI and A. A. GHOSN Table 6. Characteristics of industrial wastewater for primary industries in SIA PIC

KMI

KNPC

KNPC

KNPC(MAIA)

Sh. MAB Refinery Refinery

New Refinery

147 1100

50 150

Load Rate

(mJ/d)

BOD

~mgl1 ~kg/d

COD

~mgl1 hg/d

475 2850

100

(300) (1950)

320 2400

119 357

~mgl1 ~kgld

0 0

150 60

25 163

(40) (300)

TKN

~mgl1 ~kg/d

175 1050

900 360

(50) (325)

UREA·N

~mgl1 ~kg/d

70 420

50 20

NH 3-N

~mgl1 ~kg/d

105 630

~mgl1 ~kg/d

10

H2S Cr

TSS

Oil

Temp·re) PH

400

6500

7500

LPG

1000

1300

400

320 415

(100) (300)

(40) (40)

0 0

(40) (300)

(25) (75)

(20) (20)

0 0

0 0

0 0

0 0

0 0

0 0

700 280

46 300

283

20 60

20 20

0 0

3 1.2

17 111

27 203

10 30

28 28

4

60

~mgl1 ~kg/d

0 0

0 0

20 130

10 75

0.1 0.3

0 0

0 0

~mgl1 ~kgld

0.04 0.2

0.04 0.15

25-66 7-8.8

32 9.4

6000

40

Values in parentheses are estimated. PIC - Petrochemical Industries Company KMI - Kuwait Malimine Industries KNPC Sh. R - Kuwait National Petroleum Company - Shuaiba Refinery KNPC MAD - Kuwait National Petroleum Company - Mina Abdulla KNPC MAA - Kuwait National Petroleum Company - Mina Ahmadi LPG· Liquefied Petroleum Gas BOD· Biological Oxygen Demand COD· Chemical Oxygen Demand TSS - Total Suspended Solids TKN • Total Kjeldahl Nitrogen

3S

3000

Old Refmery

400

0.22 0.66

S

0 0 39 8.2

38 7.S

Fate of conventionaVpriority organic pollutants

7

Table 7. Soil characteristics in Kuwait (after Ergun, 1969) Desert Soils:

Soil Main Groups

Soil types - Sandy desert hardpan soils - Gysiferous desert soils - Gravelly saline desert soils - Gravelly gypsiferous saline desert soils - Saline gypsiferous desert soils - Sandy desert soils - Desert dune soils - Escarpment - Hydromorphic saline alluvial soils • Recent alluvium soils

Desert - ragosol intergrade soils Lithosols: Alluvial Soils

Table 8. Average percentage of sediments collected G. 3.1 3.5 2.4

Locatlon Wafra Sulaibiya Abdally

V.C.S 5.7 1.4 1.4

C.S 18.3 10.2 13.4

M.S 31.9 26.9 32.1

F.S 19.0 23.9 27.4

V.F.S 15.7 26.5 21.1

Mud 6.3 7.6 2.0

Sum 100.00 100.0 100.0

(G: Gravel, V.C.S: Very coarse sand, C.S: Coarse sand, M.S: Medium sand, F.S: Fine sand, V.F.S: Very fine sand).

Table 9. Properties of collected soil samples Sample Location

Average Moisture Content

Abdally Sulaibiya Wafra

1.10 0.98 1.15

Bulk Density

Porosity (%)

1.57

41 37 34

(%)

1.68 1.73

LABORATORY PILOT PLANT To assess the fate of conventional/priority organic pollutants of wastewater in soil, a test set up/ laboratory pilot plant shown in Figure 1 was designed and constructed. Due considerations were given to simulate the field seepage conditions of the soil samples tested in this study. Three testing units were assembled, each of which will allow testing three samples simultaneously. Soil core samples of"4.4Scm" in diameter and "12Ocm" in depth were collected from the selected sites in Kuwait which included Abdally, Sulaibiya and Wafra. The test cylinders were designed to allow sampling of effluents at different depths of the tested sample (3Ocm, 6Ocm, 90cm from the top of the sample). Each of these cylinders is also connected to a calibrated outflow tube to measure the soil permeability and to monitor the composition and concentration of the infiltrating contaminants. Necessary precautions were taken to avoid any leakage in the flow system and a constant flow was maintained throughout testing. Three fifty• gallons-capacity feed tanks were used as the source influent. which included industrial and tertiary treated wastewater. Table 10. Permeability coefficients for different wastewaters in Abdally area soil Type of Water Fresh Sanitary Industrial

Coefficient of Permeability, k (cm/s)

0.0017 0.0013 0.0012

Typical Ranges for "k"

0.01-0.001

8

S. AL-MUZAINI and A. A. GHOSN

LID

FEEDTAhl(

FEED TANK

SOIL

INFLlfENT SAMPLE PORTS

EfnUE~ SAMPLE PORTS

eFFLl,."EWT SAMPLE PORTS

Figure I. Laboratory Pilot Plant.

RESULTS AND CONCLUDING REMARKS The test results presented herein are only for AI-Abdally area soils. Pilot plant tests for other areas are still in progress. The coefficients of permeability "k" for the tested soil samples are summarized in Table 10 for different wastewaters. The obtained "k" values for freshwater fall within the range of values reported for similar soils. The results also indicated a relatively higher, but not very significant, "k" value for freshwater than those of industrial and tertiary treated wastewaters. The results for pore fluid analysis for extracted samples are also presented in Table 11. The analysis results covered pH, total organic compounds (TOC), dissolved oxygen (DO) and total Kjeldahl nitrogen (TKN). The pH values for fresh water indicated slight variations ranging from 7.9-8.13 for outflow samples. For other samples taken at various depths of the soil column, these values remained almost unchanged (7.8• 7.86). pH values for sanitary and industrial waters indicated a slight decrease from 8.01-7.71 and 8.28-7.25 respectivel y. The dissolved oxygen indicated a slight decrease from 7.3-6.6 for outflow samples for fresh water. Similar trends were also noted for other samples with slightly higher initial and final readings. The same behaviour was also noted for sanitary water and outllow samples for industrial water. Other industrial water samples at different soil column locations almost maintained constant dissolved oxygen value. The total Kjeldahl nitrogen (TKN) results indicated a sharp decrease for freshwater outflow samples from 8.1-0.091 and moderate decrease for other samples (15-8). A similar trend was noted for industrial water ranging from 48.6-25 for initial samples to 28-11 for final samples.

Fate of conventional/priority organic pollutants

9

The total organic content (TOC) results showed a decreasing trend from 4-2 for outflow freshwater samples and were practicaIly zeroes for other freshwater samples. The TOe values for sanitary water reflected a sharp decrease ranging from 6-3 for initial samples and 2-1 for final samples. On the other hand, the TOe values for industrial water reflected a slight decrease ranging from 34-32 for initial samples and 30.8-28.1 for final samples. While the above results may reflect some kind of interaction between the pore fluids and soil, it would be hard at this stage to finalize the interpretation of the results and to draw final conclusions. Initial pore fluid characteristics are needed and further compositional analysis of the soil samples after testing is necessary. These tasks are part of the project plan and are currently ongoing. Table 11. Results of PH, DO, TKN, and TOe for coIlected pore fluid samples (AbdaIly area soil samples) Measured Parameter

PH

DO

TKN

TOC

Freshwater OF

T

M

Sanitary water

FT

B

8.11

OF

T

M

B

Industrial water

FT

T

M

B

FT

818

8.28

825

825

7.60

7.82

7.85

7.25

Max.

813

7.91

7.82

7.88

788

8.01

7.92

781

Mm.

7.90

7.79

779

7.84

7.71

785

7.84

7.74

AV8·

7.98

786

7.80

7.86

7,78

7.92

7.89

7.79

7.92

8.08

8.15

8.00

FS.

7.92

7.86

7.79

7.88

7.79

8.01

7.85

7.74

764

7.82

8.17

800

LS

813

790

7.81

788

772

791

7.88

776

8.10

828

7.85

725

39

3.6

3.2

3I

3.4

29

2.9

26

Max.

7.3

7.4

76

7.8

Mm.

6.6

6.8

6.8

7.4

AV8·

7.0

7.2

72

7.6

36

3.2

3.0

FS

7.1

6.8

72

75

3.7

3.6

2.9

LS

66

7.4

7.2

7.6

3.6

3.2

Max.

81

15

13

13

Mm.

0.71

6

7.2

85

56

5.6

5.7

5.8

50

4.9

4.8

2.8

4.9

5.4

5.3

5.3

2.8

5.6

5.0

5.4

4.8

3.1

26 .

4.9

56

5.5

5.8

48632

++

++

21

25

20.2

18

10

9

NA NA

14

14

NA

NA

NA

NA

13

NA

NA

NA

NA

28.3

22

16

II

NA

NA

NA

NA

6

6

LS.

0.91

13

9

Max.

4

Mm.

o

o

o

o

Avg.

23

03+

0.1+

0.4+

3.3

o

o o

o

6

o

NA NA

10

13

o

NA NA

22

68

2

NA NA

23

10.4 10.

FS.

25.1

326

2.00 81

LS.

++

20.2

Avg.

7.0

53

46

FS.

10

7.65

OF

10.3

2.4 6

34.4

32.1

32.3

33.3

30.2

29.3

28.1

30.2

32.0

309

31.1

314

34.3

32.1

32.3

32.1

30.8

29.3

28.1

30.!

* Decreasing trend from 8.1 to 0.91 stable at around 1.0 in the last 4 samples .. General decreasing trend + Practically zero, most readings are zero ++ Random trend with up and down value changes NA= not available, OF= outflow sample, T= top, M= middle, B= bottom, FT= feed tank.

7.79

6.8

9.1

8.2

10

S. AL-MUZAlNI and A. A. GHOSN

ACKNOWLEDGEMENTS The authors wish to express their thanks to Dr. Ali AI-Shamlan, Director General of the Kuwait Foundation for the Advancement of Sciences (KFAS) for his support during the study. Special thanks are due to the Kuwait Institute for Scientific Research for all the facilities and support provided during the course of the study as well as for partial funding. REFERENCES AI-Muzaini, s., Sarnhan, O. and Hamoda, M. F. (1991). Sewage related impact on Kuwait's marine environment: A case study, Wat. Sci. Tech., 23,181-189. Ergun, H. N. (1969). Reconnaissance Soil Survey, Kuwait. Food Agriculture Organization of the United Nallons, Ministry of Public Works, Report No. FAOlKufTFI7. Ghobrial, F., Moulin, L, Patel, B. and Awad, A. (1987), Assessment of Raw Sewage and Treated Effluent Characteristics in Kuwait, Report No. KISR 2468, Kuwait Institute for Scientific Research, Kuwait. Ministry of Public Works (1996). Treatment Plants in Kuwait. Ministry of Public Works, Kuwait. ROPME (1986), Wastewater Discharges from Domestic Sources to the ROPME Sea Area, The Regional Organization for the Protection of the Marine Environment, Kuwait. Sarnhan, O. and Ghobrial, F. (1987). Trace metals and chlorinated hydrocarbons in sewage sludge of Kuwait, Water, Air and Soil Pollution, 36, 239-246. Shuaiba Area Authority (1990). Shuaiba Industrial Wastewater Treatmentfacilities. Shuaiba Area Authority. Kuwait.