environmental assessment of wastewater pollution in ...

CHEMICAL, BIOLOGICAL AND ENVIRONMENTAL ENGINEERING International Conference on CBEE 2009

ENVIRONMENTAL ASSESSMENT OF WASTEWATER POLLUTION IN AL-QASSIM INDUSTRIAL CITY T. I. Sabry Associate Professor of Sanitary Engineering, Ain Shams University, Cairo, Egypt. [email protected] S. M. ElKholy Associate Professor of Geotechnical Engineering, National Water Research Center, Cairo, Egypt. [email protected] S. Al-Salamah Associate Professor of Hydrology Engineering, Qassim University, Qassim, Saudi Arabia. [email protected]

A new approach for a continuous monitoring program is used to assess the status of the wastewater in the sewage network in accordance with the environmental standards and to identify the industrial contamination agents that may exist in the sewage and their possible sources. Moreover, an investigation program is used to assess the potential contamination of the surrounding soil and groundwater due to leakage from the sewage ponds. Five wastewater paths (streams) were selected in the sewage network to trace and follow the sources of the pollutants by collecting samples from selected locations (manholes) in these paths. In order to examine the existence of polluted industrial wastewater in the sewage network, the pollutants concentrations were compared with their extreme values in Buraidah domestic sewage and with their allowable values in the Saudi Executive register (SER) standard for treated wastewater and reuse (Ministry of water and electricity). The study showed the existence of polluted industrial wastewater in the sewage network. However, except for TDS values in the Northern pond and NH3-N values in the Southern pond, the pollutants concentrations entering the ponds have rarely exceeded the law limits due to the dilution factor with other low pollutants concentrations from the lowpolluted factories. The study also showed that there is some seepage of the wastewater into the surrounding soil and groundwater. This seepage resulted in an increase in the concentrations of the pollutants agents compared to the typical values found in other sites within the City of Buraidah.

1.

Keywords

Industrial wastewater, wastewater pollution assessment, sewage network, soil and groundwater pollution recycle such waste within the production process. 2. Introduction and Literature Review Minimizing wastewater and emissions, and using raw materials more efficiently are some of the gains several 2.1. Wastewater contamination industries have seen through using good housekeeping Industrial technology usually involves the use of a management. However, many industries remain huge amount of chemicals to keep modern life dependent on processes that produce large amount of humming. Therefore, factories dump more than 220 wastewater (4). million pounds of toxic chemicals into surface water The generated wastewater contaminants from some each year, relying on dilution to render them harmless. sources of pollutions are introduced in the following However, pollutants still accumulate in bottom sections: (1), (2), (3), (4), (8) sediments or become part of the food chain, sometimes causing serious threats to human health later on (12). Food industry. Wastewater generated from agricultural and food industries have distinctive characteristics that set it apart from common municipal wastewater managed by public or private wastewater

Most industries produce some wet waste, although recent trends have been to minimize such production or Singapore, 9 - 11 October 2009

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treatment plants. It is biodegradable and nontoxic, but it has high concentrations of biochemical oxygen demand (BOD) and suspended solids (SS). Complex organic chemicals industry. A wide range of industries use complex organic chemicals such as pesticides, pharmaceuticals, paints and dyes, petrochemicals, detergents, plastics etc. Wastewaters can be contaminated by feed-stock materials, by-products, product material in soluble or particulate form, washing and cleaning agents, solvents and added value products such as plasticisers. Many authors have review articles in the wastewater treatment and recycling in the textile processing industry (5), (7). Rott et al (7) gave some examples of applied and effective end-of-pipe-steps in the textile processing industry. Water treatment. Water treatment for the production of drinking water is likely to be found in any industrial cities. Many industries have a need to treat water to obtain very high quality water for demanding purposes. Water treatment produces organic and mineral sludge from filtration and sedimentation processes. Fertilizer Manufacturing. The expected main constituents of fertilizers industry wastewater are: Nitric, sulfuric, phosphoric acid, anhydrous ammonia, organics, ammonium nitrate, sulfate, phosphate, chloride, and Urea. Disposal of wastewater from such industrial plants is a difficult and costly process. Nowadays, most industries have onsite facilities to treat their wastewater so that the pollutant concentrations in the treated wastewater comply with the local and/or national regulations (4), (8). 2.2. Soil Contamination It is defined as the presence of man-made chemicals or other alteration in the natural soil environment. This type of contamination typically arises from the rupture of underground storage tanks, application of pesticides, and percolation of contaminated surface water to subsurface strata, leaching of wastes from landfills or direct discharge of industrial wastes to the soil. The most common chemicals involved are petroleum hydrocarbons, solvents, pesticides, lead and other heavy metals. The occurrence of this phenomenon is correlated with the degree of industrialization and intensity of chemical usage. The concern over soil contamination Singapore, 9 - 11 October 2009 2

stems primarily from health risks, both of direct contact and from secondary contamination of water supplies. Contaminants in the soil can hurt plants when they attempt to grow in contaminated soil and take up the contamination through their roots. Contaminants in the soil can adversely impact the health of animals and humans when they ingest, inhale, or touch contaminated soil, or when they eat plants or animals that have themselves been affected by soil contamination. Animals ingest and come into contact with contaminants when they burrow in contaminated soil. Humans ingest and come into contact with contaminants when they play in contaminated soil or dig in the soil as part of their work. Certain contaminants, when they contact our skin, are absorbed into our bodies. When contaminants are attached to small surface soil particles they can become airborne as dust and can be inhale. 3.

Research Problem and Objectives

The industrial city of Al-Qassim, which lies at the Southern entrance of Buraidah City, has been at work for more than 25 years. The city comprises industries such as aluminum products, food industries, fertilizing, metal plating, pharmaceutical manufacturing, and desalinated water treatment, which may produce potential hazards to the surrounding environment (air, soil, and water resources). The sewage system in the city relies on collecting sewage into two large ponds, with total area of 6 hectares, and treating it by the biodegradation action of aerobic/ anaerobic bacteria. These ponds are known as “stabilization ponds”. However, the common practice now is to use the ponds as evaporation ponds without sewage outlet. Bad smell and colored waste water have frequently been detected in the stabilization ponds, especially the Southern one. Those are primary evidence of the existing of the contaminated industrial wastewater in these ponds. The sides and bed of the ponds are lined with polyethylene sheets in order to protect the soil and groundwater from getting contaminated through seepage of sewage. However, since their construction, none of the stabilization ponds, the soil, or the groundwater has ever been examined for potential wastewater seepage which shows the necessity for the current study.


Wastewater seepage or wastewater overflow are expected since there is no sewage outlet from these ponds and evaporation rate might not match the inlet flow rate.

Southern Lagoon

Labor residence area

S1

The objectives of the current research can be summarized as follows: 1.

Polystyrene Manufacturing & Food Processing Factory 2

Path 5

Identifying the industrial contamination elements that could exist in the sewage and their possible sources.

S3 S2 Textile Factory

2.

Examining the status of the wastewater in the sewage network in accordance with the environmental standards.

3.

Investigating the possible leakage from the ponds into the surrounding soil and groundwater.

4. 4.

contributed on the wastewater pollution are illustrated in Figures (1) and (2). Figure (1): Sewage network for the Northern part of the industrial city

Figure (2): Sewage network for the Southern part of the industrial city

Remediation program of industrial pollutants. Table (1) shows the type of these factories and their wastewater inlet locations in the sewage network. Table (1): Factories that have polluted wastewater and their disposed location Factory Type Inlet Location Pharmaceutical Manufacturing N9 Metal Plating N8 Food Processing 1 N7 Desalinated Water Treatment Plant N6 Vitrified Clay Brick Manufacturing N3 Liquid Fertilizer Manufacturing N1 Textile S3 Polystyrene Manufacturing S2 Food Processing 2 S2

Methodology

4.1. Sampling Locations and Analysis: The existing sewage networks are divided into two parts: Northern part and Southern part, and each part is connected to one of the stabilization ponds. Grab water samples are collected from critical locations (manholes) in the network and numbered from downstream to upstream of the network. In the numbering system, the letters "N" and "S" stand for Northern Lagoon Food Processing Factory 1

N2

N4

N1

Path 3

Path 4

Path 2

Path 1

N3

Four streams in the Northern sewage pipelines and one stream in the Southern sewage pipelines were selected to trace and follow the sources of the pollutants throughout these streams as shown in the Figures (1) and (2). The five paths (streams) are as follows:

Metal Plating Factory

N7 Liquid Fertilizer Manufacturing

N8

N6 Pharmaceutical Manufacturing

N5 N9

Vitrified Clay Brick Manufacturing

Path 1: N3, N2, N1; Path 2: N6, N5, N4, N1; Path 3: N8, N7, N4, N1; Path 4: N9, N7, N4, N1; and Path 5: S3, S2, S1

Desalinated Water Treatment Plant

Northern and Southern networks, respectively. The selected sampling locations in the network and the type of the existing heavily polluted factories that may have Singapore, 9 - 11 October 2009

To identify the existence of industrial wastewater pollution in the sewage network, the pollutants concentrations were compared to their extreme values in 3


the Buraidah domestic sewage. The data of the Buraidah domestic sewage characteristics (BSC) were collected from the raw sewage that enters the Buraidah wastewater treatment plant during the last 5 years.

4.2. Soil and Groundwater Investigations:

Total suspended solids (mg/l), TSS

600

For the current environmental study, the data collected for soil and groundwater samples constitute a small subset of the possible values. In order to assess the existence and the extent of any soil/groundwater contamination due to leakage from the stabilization ponds of the sewage network, an exploratory drilling program was implemented. The program comprised four exploratory boreholes which have been drilled to a maximum depth of 15.0m each at the vicinity of both Northern and Southern ponds. Groundwater level was carefully observed for each borehole. Soil and groundwater samples from boreholes have been carefully collected at pre-set intervals under the close supervision of field geologist. The collected samples were subjected to chemical analyses to detect the existence of any pollutants. Moreover, two surface water samples were collected from overflow spots that occurred outside the boundary wall of the industrial city near the southern pond were thoroughly analyzed.

pH

6-9

5.

Biochemical oxygen demands (mg/l), BOD

500

Chemical oxygen demands (mg/l), COD

1000

Pollutants concentrations were also compared to the maximum allowable limits for the disposal of raw wastewater in the Saudi Executive register (SER). For the industrial wastewater, SER asks the factories to have wastewater pretreatment before disposing their wastewater into the municipal sewer lines. Table (2) shows the SER standards for the industrial wastewater that may be disposed into municipal sewer lines. Table (2): Some of the parameters allowable limit for the raw wastewater that may be disposed into municipal sewer lines according to SER Parameters

Max. Allowable Limit (mg/l)

Ammonia (mg/l), NH3-N

80

Phosphate (mg/l), PO4

25

 Results of Waste Water Analysis For more than 6 months of monitoring and analysis, 3 to 5 samples were collected from each location at the most critical locations in the sewer pipeline and 1 to 2 samples were collected from each location at the less critical locations in the sewer pipeline. These samples were analyzed for determining the required parameters. The pollutants concentrations at the five streams are compared to their maximum limits in the Buraidah Sewage Characteristics (BSC), table (3), and in the Saudi Executive register (SER) standards for treated wastewater and reuse (Ministry of water and electricity), table (2). SER does not include limiting value for the TDS concentration in Table (2). However, it mentions the maximum limit for TDS of the treated sewage to be used in the irrigation, which is 2500 mg/l. Since TDS concentration is nearly not influenced by the conventional treatment process, TDS of 2500 mg/l was used in the study as the maximum permissible value for the TDS in the industrial wastewater.

Biochemical oxygen demand (BOD), Chemical oxygen demand (COD), Total suspended solids (TSS), Total Dissolved Solids (TDS), Ammonia (NH3-N), Nitrate (NO2), and orthophosphates (PO4) contaminants concentrations were determined according to the Standard Methods for the Examination of Water and Wastewater (APHA, 1995) (6). Although some industries can produce other contaminants, such as heavy metals in metal plating industry and fluoride and silicate in fertilizer manufacturing, in addition to that mentioned in the above paragraph, the above-chosen parameters for analysis considered the minimum requirements for detecting the contamination for all types of the existing industries. Singapore, 9 - 11 October 2009

Results and Discussion

Table (3): Some of parameters values for the raw sewage entering Buraidah wastewater treatment plant 4


Parameters

Some TDS concentrations at N1 are much higher than the SER allowable limit. The TDS values for all other locations upstream N1 are less than or slightly higher than the SER allowable limit. This indicates that the potential source of this high TDS values is the nearby liquid fertilizer manufacturing company.

Values

Total suspended solids (mg/l), TSS

130- 340

pH

6.5- 8.7

Biochemical oxygen demands (mg/l), BOD

120- 190

Chemical oxygen demands (mg/l), COD

240- 450

Ammonia (mg/l), NH3-N

14- 30

Phosphate (mg/l), PO4

15- 35

The TSS values through stream 1 are always less than the law limit but sometimes higher than that of the value of BSC especially at N3 and N2 locations (581 and 546 mg/l, respectively). These rather high TSS values at N3 and N2 locations can be originated from the clay particles that are disposed from the vitrified clay brick manufacturing company into the sewer line.

COD concentrations were measured at selected locations in the sewage network. The results of the average COD concentrations are presented in Table (4):

The low pH value, which is 3.2, at N2 location in only one sample, is perhaps due to the disposal of acidic solutions that probably used in small factories that are connected to path 1. Except this, pH values are always within the normal limits.

Table (4): Values of the COD concentrations at the selected locations

Path 2:

Location N1 N4 N6 N8 S1 S2 S3 830 757 1980 430 939 1800 1930 COD, mg/l As shown in Table (4), all COD values are high and much higher than that of BSC (maximum 450 mg/l) except for location N8. However, only locations N6, S2, and S3 have COD values violating the limits that mentioned in the SER (maximum 1000 mg/l). The average COD values at both ends of the networks, at N1 and S1, are close but less than the SER limit. This can be attributed to the dilution factor that happened due to mixing of the human excrete with the industrial wastewater especially for S1 where large labor compound sewage collector is connected to stream 5 just before S1 location. The ratios of BOD to COD in the selected locations ranged between 0.21 and 0.32 which are much less than the typical values for domestic sewage in Buraidah city which is around 0.5. This indicates that the raw industrial wastewaters of some factories are disposed directly into the sewage network without treatment. This value is only close to that of the domestic sewage at location N8.

At N6 location, the BOD, COD, and TDS values are higher than that of SER allowable limits. The high TDS value is mostly due to the disposal of the brine water (refused salts) from the desalinated water treatment plant into the sewer line. However, the TDS values at N5 location are always less the 2500 mg/l due to the dilution with other low-TDS wastewater. Although the TSS values at N4 location with an average value of 845 mg/l are higher than the SER limit, the TSS values at locations upstream of N4 in paths 2, 3, 4 are less than SER limit. The wastewater of small glass manufacturing company, which is located close to N4, can be the reason for the high TSS values at N4. Path 3: Almost there is no indication of polluted industrial wastewater in the sewer path 3 up to N4 location. The BOD and COD concentrations, which are 270 mg/l and 430 mg/l, at N8 location is less than SER limit and they are close to the average concentrations of BOD and COD in the BSC. The very high BOD value (1066 mg/l) at N7 location can be resulted from the wastewater of the food processing factory 1. At location N8, there is no evidence of any polluted wastewater (solids or organics) coming from metal plating company.

The results of each of the five streams are discussed in the following sections: Path 1:

Singapore, 9 - 11 October 2009

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 Results of the Overflow Water Samples from the Ponds:

Path 4: As in path 3, there is no evidence of polluted industrial wastewater coming from the pharmaceutical manufacturing company (solids or organics). However, it should be taking into account that the results of the TSS and TDS concentrations at N9 location, which are 520 mg/l and 2394 mg/l, are close to, but less than, the SER limits. Heavy metals and COD concentrations analysis for the Pharmaceutical Manufacturing wastewater need to be done to ensure this result. Only one sample was taken from N9 location because the manhole at this location is always dry whenever samples were collected.

The overflow water samples were analyzed to determine the chemical indices, and the results are summarized in Tables (5). Table (5): Chemical indices of the two overflow water samples

Path 5: Contradictory to the Northern sewage network, the wastewater in the southern sewage network seemed to be more polluted, although the number and size of the factories into this part are much less than the Northern part. This can be attributed to that wastewater in the southern sewage network imposes to higher organic loads than that of Northern sewage network. Some results of TSS values such as 2530 mg/l, COD values such as 1930 mg/l, and pH values such as 5.25 are higher than SER limit at S3 location. This indicates that Textile factory is discharging wastewater that is not complying with the SER standards. Also at S2 location, some values of BOD such as 507 mg/l, COD such as 1800 mg/l, and pH such as 4.6 do not comply with the SER standards. The source of these pollutants can result from the textile factory and/or from the food processing2 company as the BOD "the main source of pollution in the food processing" value is higher than the allowable limit. There is no evidence that polystyrene manufacturing company is polluting the sewage network.

Value For Sample # 1

Value For Sample # 2

Max. Allowable Limit (mg/l)*

pH – at 250C

7.42

7.37

6- 8.4

Electrical Conductivity (micro ohms/cm)

3350

5140

Total Dissolved Salts (mg/l)

2155

3245

--

Total Alkalinity (M) as CaCO3 (mg/l)

132

128

--

BOD5 (mg/l)

62

54

40

COD (mg/l)

155

135

--

Ammonium (mg/l)

0.6

0.44

5

Sodium (mg/l)

258

447

--

Potassium (mg/l)

5

6

--

Chlorides (mg/l)

412

690

--

Sulfates (mg/l)

785

1185

--

Bicarbonate (mg/l)

162

156

--

Nitrate (mg/l)

22

27

10

Total Phosphorus (mg/l)

3.27

5.16

--

Total Plate Count (/100ml)

900

346

--

Total Coliform Bacteria (/100ml)

208

52

1000

--

The results show agreement with the results of the analysis of the sewage water samples collected from the wastewater inlets to ponds. The ponds overflow incidents show the threats of soil contamination in case the storage capacity of the ponds are exceeded.

Although, this part of sewage network is heavily polluted at some locations, the wastewater at the outlet network location at S1 is not polluted, except for NH3N value which was 371 mg/l, and their pollutant concentrations are less than the SER limits. This can be attributed to the dilution that occurs with the domestic wastewater of the labor compound and from nonpolluted wastewater of the small factories that exist along with the sewage stream. Singapore, 9 - 11 October 2009

Parameter

 Results of Soil and Groundwater Analysis The results of the field and lab tests revealed that the soil profile comprises the following: Northern Pond Soil profile: a surface soil layer, followed by intercalated layers of fine sand and silty sand, and then a 6


soil samples. Some of the results are presented in Tables (6) and (7). Table 6: Chemical indices of borehole water samples in mg/l* * SER standard limits are similar to that in table 5 Table 7: Results of chemical analysis of borehole soil samples in mg/l* * SER standard limits are similar to that in table 5 The results of the chemical analysis show that, for the tested spots, the contaminations concentration in the soil are within the normal figures in this region and do not show evidence of contamination until now. This is attributed to the effectiveness of the geotextile sheet that is used to protect against possible seepage from the stabilization ponds.

NO. Parameters

B.H.# 01

B.H.# 02

B.H.# 03

B.H.# 04

2.0 - 3.0

1.5

9.0 - 10.5

7.23 1625

7.26 2150

7.24 1890

4.5 6.0 7.31 2235

221 635 2.5

290 690 2.7

260 650 2.5

330 785 3.4

06

Depth of sample (m) pH- Value Total Soluble Salts Chlorides Sulfates Total Phosphorus Ammonium

07

Nitrate

Not Detect. 2.2

Not Detect. 2.6

Not Detect. 3.3

Not Detect. 3.1

01 02 03 04 05

moderately weathered limestone layer. The ground water level settled at an approximate level of 5.5 m from ground surface.

6.

Southern Pond NO. Parameters

B.H.# 01 WS-01

B.H.# 02 WS-01

B.H.# 03 WS-02

7.24 3570

7.33 3875

7.38 3075

2320

2520

2000

2750

04 05 06

pH – Value Electrical Conductivity (micro ohms/cm) Total Dissolved Salt Chlorides Sulfates BOD

B.H.# 04 WS-01 7.32 4235

365 795 Not Detected



07

COD

Not Detected

Not Detected

Not Detected

08

0.05

0.07

0.06

09

Total Phosphorus Ammonium

426 1310 Not Detecte d Not Detecte d 0.08

Not Detected

Not Detected

Not Detected

10

Nitrate

8

7

8

01 02

03

Not Detecte d 8

Soil profile: a surface soil layer, followed by a layer of weathered limestone extended to the end of the borehole. The ground water level settled at an approximate level of 3.0 m from ground surface. Chemical Analysis: Various parameters have been taken into account for the detailed chemical analysis of the boreholes water and Singapore, 9 - 11 October 2009

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Conclusion and Recommendation

The results of investigating the status of contamination in wastewater of the Industrial City of Buraidah show evidence of contamination with industrial wastewater at some locations that are not in comply with the Saudi laws and regulations. Although, almost all wastewater pollutants values in the final outlet to ponds complied with the Saudi law, this shall not give the right to noncompliance industries to dispose polluted wastewater in the sewage network. These factories shall change their conditions and make their disposed wastewater comply with the law. From this study, the source of the polluted wastewaters in the sewage networks are expected to be from the liquid fertilizer manufacturing, textile manufacturing, and food processing industry. For those non-compliance industries with the Saudi law, Best Management Practices (BMPs) can be implemented to reduce contaminants from entering sewage network (source controls) or to treat their wastewater before disposing it into the sewage network (treatment controls). In general, source controls are more effective in reducing pollutant levels in sewage network, and are therefore, preferred by EPA and other regulatory agencies (9), (10), (11). The results of testing the soil and groundwater in the region don't show serious evidence of contamination at the investigated spots of the stabilization ponds. However, the threat of overflow from the stabilization ponds into the surrounding areas of the industrial city must be thoroughly observed and monitored in order to safe guard the environment against possible increase in the sewage collected in the ponds beyond the storage capacity.


6. Standard Methods for the Examination of Water and Wastewater, (APHA, 19th Edition, 1995), Available at www.standardmethods.org.

Acknowledgement This research work is a research grant with title "Environmental Study for the wastewater contamination in Al-Qassim industrial city" which is supported by scientific research unit in Qassim University, Saudi Arabia.

7. U. Rott , and R. Minke, Overview of wastewater treatment and recycling in the textile processing industry. Water science and technology , ISSN 02731223 , CODEN WSTED4, (1998).

References

8. G. Tchobanoglous, F.L. Burton, and H.D. Stensel, Wastewater Engineering (Treatment Disposal Reuse) / Metcalf & Eddy, Inc., 4th Edition, McGraw-Hill Book Company. ISBN 0-07-041878-0, (2003).

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9. U.S. Environmental Protection Agency. "EPA Administered Permit Programs: The National Pollutant Discharge Elimination System." Code of Federal Regulations, 40 CFR 122.2.

2. American Petroleum Institute (API), Management of Water Discharges: Design and Operations of Oil-Water Separators, 1st Edition, American Petroleum Institute, (February 1990).

10. U.S. Environmental Protection Agency. Washington, D.C. "Guidance Manual for Developing Best Management Practices (BMP)." Chapter 3. October 1993. Document No. EPA-833-B-93-004.

3. M. R. Beychok, Aqueous Wastes from Petroleum and Petrochemical Plants, 1st Edition, John Wiley & Sons. LCCN 67019834, (1967).

11. U.S. Environmental Protection Agency. EPA, Office of Water Regulations and Standards. Preliminary Data Summary for the Pharmaceutical Manufacturing Point Source Category, EPA 440/1-89/084, U.S. Environmental Protection Agency, Washington, D.C. September 1989.

4. Industrial wastewater treatment from Wikipedia, the free encyclopedia. http://en.wikipedia.org/

wiki/Wastewater 5. Philippe C. Vandevivere, Roberto Bianchi, and Willy Verstraete, Review: Treatment and reuse of wastewater from the textile wet-processing industry: Review of emerging technologies. Journal of Chemical Technology & Biotechnology, volume 72 Issue 4, Pages 289 – 302, (1999).

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12. Woods hole oceanographic institution. Industrial pollution, http:// www.whoi.edu/page.do?pid=1246

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