Water Quality Monitoring at Perai Industrial Park During Wet Season

Transcription

1 Water Quality Monitoring at Perai Industrial Park During Wet Season KHAIRUL RAHMAH AYUB, Tutor, River Engineering and Urban Drainage Research Centre (REDAC), Universiti Sains Malaysia, Engineering Campus, Seri Ampangan, Nibong Tebal, Penang, Malaysia FARIDAH ABU HASSAN ASAARI, Lecturer, School Of Civil Engineering, Universiti Sains Malaysia, Engineering Campus, Seri Ampangan, Nibong Tebal, Penang, Malaysia ROZI ABDULLAH, Lecturer, School Of Civil Engineering, Universiti Sains Malaysia, Engineering Campus, Seri Ampangan, Nibong Tebal, Penang, Malaysia LAU TZE LIANG, Lecturer, School Of Civil Engineering, Universiti Sains Malaysia, Engineering Campus, Seri Ampangan, Nibong Tebal, Penang, Malaysia NOR AZAZI ZAKARIA, Director, REDAC, Universiti Sains Malaysia, Engineering Campus, Seri Ampangan, Nibong Tebal, Penang, Malaysia AMINUDDIN AB. GHANI, Deputy Director, REDAC, Universiti Sains Malaysia, Engineering Campus, Seri Ampangan, Nibong Tebal, Penang, Malaysia ABSTRACT Since November 2003 until January 2004, a data collection programme on water quality was established at Perai Industrial Complex. With the total area of hectares, more than 300 factories involve in the commercial and industrial activities in the area. Thus wastewater discharges increases year by year and have affected the nearby waterways and sea. The three month study in the area during a wet season not only shows that purification and dilution of wastewater do not occur due to the stagnant condition of waterways. So, there is a need for the developed industrial area to have a better drainage but also wastewater treatment system to conserve the natural environment. Keywords: Wastewater, water quality, self-purification, wet season. 1 Introduction The Study area, Perai Industrial Complex, is located on mainland of Penang State (Figure 1). The Study area with the total area of hectares was developed by Penang Development Corporation (PDC) in 1971 into the biggest industrial park in Malaysia to date. It comprises Prai Industrial Park and Prai Free Industrial Zone ( hectares) Currently, most of the industrial wastes water in the study area are discharged directly to drains or other waterways. The discharge of most of the industrial wastes water without proper treatment is causing increased pollution in the existing drains, rivers and other downstream area. Wastewater flow through the nearest downstream and eventually polluting the beaches and offshore marine waters due to low flow in dry season. Finally, this condition has resulted in adverse biological effects, odours and nuisances. It is evident that the pollution causing by industrial wastewater will become more apparent in the future if no action is taken 454

2 to improve or alleviate the drainage system in the study area. Due to consciousness of Penang State Government, Majlis Perbandaran Seberang Perai (MPSP) is intended to upgrade the stormwater drainage facilities for quantity and quality control in the study and surrounding area. Hence, MPSP has requested the River Engineering and Urban Drainage Research Centre (REDAC), Universiti Sains Malaysia to study the drainage system and the water pollution problems in the Kawasan Perindustrian Perai. Legend Study Area Figure 1 Map of Seberang Perai [1]. 2 Project Background Perai Industrial Complex is located in Seberang Perai Tengah, Penang (Figure 2). Perai Industrial Complex is divided into four zones, namely Kawasan Perusahaan Perai 1, 2, 3 and 4. This area have been fully developed into an industrialise region except some coastal area which still remain as mangroves area. The Study area covers part of Kawasan Perusahaan Perai 1, the whole Kawasan Perusahaan Perai 2 and 3, some villages and residential area adjacent to Kawasan Perusahaan Perai 3. The study area is severely polluted by industrial and commercial effluent. The untreated effluent may contain toxic material and excess concentration of pollutant that are contaminating the waterway and the sea and disrupting the aquatic ecosystem consequently. Due to flat and low-lying ground platform level, the drain water tends to stagnate and decompose, causing drain water black in colour, odours, in viscous liquid form, visible nuisance as well as hazards to public health. The mean annual rainfall is approximately 267 cm, which is evenly distributed throughout the year. There are two wet periods during the year, which occur between April to May and September to November, when the Intertropical Convergence Zone passes over the area. Dry period occurs from December to March, whilst a transitional period of moderate rains occurs from June to August. The maximum amount of precipitation generally occurs in September and October. The nearest rainfall station in the Study area is situated in Kompleks Prai ( No ) and Permatang Rawa ( No ). During the study, the heaviest rainfall has occurred on November 2003 and followed by December The distributions of the monthly and mean annual rainfall for the study area are given in Table 1 and Figure 3. 3 Water Quality Problems The study area is severely polluted by industrial and commercial effluent which is discharged to the nearby waterway. Several site visits and an industry survey were carried out in order to identify the sources and types of wastewater in the 455

3 study area. Basically, any body of water is capable of assimilating a certain amount of pollution without serious effects because of the dilution by the stormwater and selfpurification factors. However, the water quality in the existing drains may be affected by the frequency of pumping activities by the both pumping stations in the study area. Figure 4 shows the present wastewater condition of the study area on 4 th November Monitoring and Sampling Period Wastewater was sampled and analyzed on November 2003 until January A total of eighteen sampling points were established in order to collect water samples for analysis (Figure 5). Six monitoring stations are chosen in Kawasan Perusahaan Perai 1, nine monitoring station in Kawasan Perusahaan Perai 2 and three monitoring stations at Kawasan Perusahaan Perai 3. Figure 2 Location of Study Area [2]. Table 1 Mean Monthly and Annual Rainfall Statistic ( ) [3]. Stn. Name Rainfall Depth (mm) (Stn. No.) Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Total Permatang Rawa ( ) Kompleks Prai ( ) Average

4 Rainfall Depth For Juru ( November January 2004) 250 Rainfall Depth (mm) November, 2003 December, 2003 January, 2004 Month Figure 3 Rainfall Depth for Juru (November 2003 January 2004). (a) (b) Figure 4(a)-(b) Wastewater conditions in study area [2]. At each location, at least three samples (1.5L) were collected. Water samples of the selected locations were analyzed and these monitoring stations are considered to represent the water quality in selected drains in the study area. 5 Preliminary Results of Wastewater Analysis The results obtained are discussed in comparison with Environmental Quality (Sewage and Industrial Effluents) Regulations (i) ph In general the phs for most of the sampling stations were well within the compliance limit of Standard B, where the ph range is (Figure 6). If ph is less than 5.5 (indicating acidic condition) or greater than 9.0 (alkaline condition), this shows that the water will support very few, if none at all, aquatic microorganisms. Even though November 2003 and December 2003 are considered wet season, it was found that ph values are not consistent compared to dry season on January However, ph values for the most monitoring stations on November 2003 are well within the compliance limit 457

5 except MS 7 and MS 17 which is slightly lower than the value stated in Standard B, EQA Throughout December 2003, ph values are lower than the compliance value of 5.5 for several monitoring stations. On 18 th December 2003, MS 7 (2.27), MS 17 (2.21) and MS 18 (2.05) show the lowest value of ph respectively. This indicates that those monitoring stations were polluted and have very few aquatic microorganisms (Table 2). (ii) Temperature ( o C) In-situ test for temperature show all the monitoring stations on November 2003 until January 2004 comply with the Standard B, EQA 1974 which mean must be equal or lower than 40 o C (Table 3). (iii)bod 5 (Biochemical Oxygen Demand) The BOD 5 test is very important to determine the resultant pollution strength of wastewaters if discharged into natural watercourses or drains. According to Standard B, EQA 1974, the BOD 5 of the effluent must be equal to or less than 50 mg/l. On November 2003, MS 7 and MS 4 have very high concentration of BOD 5. In December 2003, MS 7 still has the highest concentration of 78 mg/l to 348 mg/l. Throughout January 2004, concentrations of BOD 5 increases especially on 14 th January 2004 where only three monitoring stations do not exceed the Standard B, EQA 974. Table 4 summarizes all results in the study area. Figure 5 Location of Monitoring s [2]. 458

6 Table 2 ph Value. ph MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS Standard B, EQA 1974 limit: ph = Table 3 Temperature in study area. Temperature ( o C) MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS Standard B, EQA 1974 limit: Temperature = 40 o C Table 4 Biochemical Oxygen Demand (BOD 5 ). BOD 5 MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS Standard B, EQA 1974 limit: BOD 5 = 50 mg/l (iv) COD (Chemical Oxygen Demand) COD test is used as a means of measuring the organic strength of wasteswaters. It is based upon the fact that all organic compounds, except for a few, can be oxidized by the action of strong oxidizing agents. According to Standard B, EQA 459

7 1974, the COD values must not exceed 100mg/L for industrial wastewater. Most of the time on November 2003, MS 7 has high concentrations of COD and this indicates that high organic pollution occurred in the area. The highest value of COD that is indicated at MS 7 is 7000 mg/l for water sampled on 13 th November Even though COD content at MS 7 on December 2003 are still high but concentration of COD in other monitoring stations also increase extremely. Concentration of COD at MS 1 (66000 mg/l) shows the highest value for water sampled on 11 th December 2003, in fact for the month of December 2003 too. For water sampled on 18 th December 2003 and 24 th December 2003, most of the monitoring stations are not in compliance with the Standard B, EQA The concentrations of the COD are very high with the range of 125 mg/l to 1288 mg/l respectively. On January 2004, MS 7 has the highest contaminated by organic pollutant with the range of 1900 mg/l to 7000 mg/l. Other six monitoring stations are not in compliance throughout the study period with the value stated in Standard B, EQA 1974 are MS 1 (106 mg/l mg/l), MS 4 (288 mg/l 751 mg/l), MS 6 (130 mg/l 190 mg/l), MS 13 (172 mg/l 280 mg/l), MS 14 (108 mg/l 284 mg/l) and MS 17 (104 mg/l 159 mg/l) (Table 5). (v) Suspended Solids (SS) The suspended solids determination is extremely valuable in the analysis of polluted waters. According to Standard B, EQA 1974, the permissible SS value is 100mg/L for industrial wastewater. Table 6 shows all only three water sampled on November 2003 are not in compliance with the standard and the rest are well within the limit. However on December 2003 the number of monitoring stations that complied with the Standard B, EQA 1974 decreased and the highest values of SS was indicated in MS 1 (1100 mg/l). On January 2004, the monitoring stations that are not in compliance with the standard decrease with the range of 110 mg/l to 825 mg/l. MS 7 has the highest concentration of suspended solids followed by MS 4. Nine monitoring stations do not exceed the standard of 100 mg/l. Table 6 shows that MS 2 (10-55 mg/l), MS 8 (12-55 mg/l), MS 9 (2-42 mg/l), MS 12 (8-81 mg/l), MS 14 (24-58 mg/l), MS 15 (2-38 mg/l), MS 16 (3-22 mg/l), MS 17 (12-34 mg/l) and MS 18 (3-7 mg/l) are well within the standard. Table 5 Chemical Oxygen Demand. COD MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS Standard B, EQA 1974 limit: COD = 100 mg/l 460

8 Table 6 Suspended Solids. SS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS Standard B, EQA 1974 limit: SS = 100 mg/l (vi) Oil and Grease Oil and grease is not soluble in water, is lighter than water and therefore floats. This layer of oil and grease may hinder the exchange of gases particularly oxygen and therefore may cause anaerobic condition to occur in the water body beneath this top layer. The EQA (1974), Standard B maximum permitted value for oil and grease concentration in wastewater is 10 mg/l. From the Table 7, it shows all monitoring stations do not exceed the compliance limit on November 2003 however the values increases on December 2003 especially water that was sampled on 11 th December The highest concentration was indicated in MS 1 (19661 mg/l) followed by MS 14 (3015 mg/l) and MS 13 (2030 mg/l). Results on January 2004 shows the concentration of oil and grease in each monitoring station are lower than permitted values of Standard B, EQA 1974 except for MS 14 (25.8 mg/l) where the water sampled on 14 th January Detail is shown in Table 7. (vii) Sulphide, SO 2- Sulphide is formed during the reduction of sulphate and is associated with smell. If the ph of the wastewater is 8 or above the reduced sulphur is in the form of HS - and S 2- and odour problem does not occur but at ph lower than 8, it shifts to form unionized H 2 S and cause serious odour problem. However, H 2 S in the presence of oxygen and bacteria can convert sulphide to acid sulphuric and cause corrosion problem in concrete sewer systems. Therefore the EQA (1974) Standard B maximum permitted value for sulphide is 0.5mg/L. Table 8 shows the sulphide contents in all the water sampled were lower than 0.25mg/L on 4 th November 2003 and on 19 th November 2003 the range is mg/L. However, on 13 th November 2003 the concentration of Sulphide for MS6 (3.85mg/L) and MS7 (0.59mg/L) exceeded the Standard B, EQA (1974). On December 2003 shows sulphide contents in most monitoring stations are not in compliance with the standard especially on 11 th December 2003 and 18 th December Water sampled on 18 th December 2003 shows the highest values of sulphide are recognized at MS 4 (36.3 mg/l) and followed by MS 2 (23.8 mg/l) and MS 12 (15.35 mg/l). Throughout January 2004, MS 4 is identified not complied with the standard and shows highest concentration of sulphide on 20 th January 2004 (47.2 mg/l). On 28 th January 2004, the concentrations of sulphide in MS 4 decreased but still exceeded the standard with values of mg/l. Detail figures on concentrations of sulphide in the study area are presented in Table

9 (viii) Boron, B Boron is normally found in low concentration in domestic and industrial wastewater owing to its perborate content during detergent preparations. Small concentrations are not harmful to man but are harmful to plants when present in contaminated irrigation water. The permissible value in Standard B, EQA (1974) for boron is 4.0 mg/l. From the results, all water samples from 18 sampling stations on 13 th November 2003 comply with the Standard B value except for MS7 (53mg/L). Water sampled on 19 th November 2003 show MS7 (5.6mg/L) and MS6 (6.5mg/L) do not comply with the limit of Standard B. 4 th December 2003 and 11 th December 2003, water sampled in MS 7 (6.6 mg/l and 9.2 mg/l) is not compliance with the standard and the other monitoring stations are in the range of mg/l and mg/l respectively. On 18 th and 24 th December 2003, all monitoring stations do not exceed the standard value. The range for both date are mg/l and mg/l respectively. Throughout January 2004, all monitoring stations are in compliance with the standard in the range of 0.1 mg/l 3.4 mg/l except for MS 7. MS 7 has very critical values of Boron with the range of 11.5 mg/l 22.0 mg/l. Table 9 show the summary of Boron concentration in the study area for November 2003 until January (ix) Free Chlorine Free chlorine refers to chlorine, hypochlorous acid or hypochlorite ion found in water and they are also powerful oxidising agents. For Standard B EQA (1974) the permissible amount of free chlorine is 2.0mg/L. Concentration of free chlorine on November 2003 are determined to be well within the standard for all monitoring stations. Water sampled on 4 th December 2003, 11 th December 2003 and 18 th December 2003 shows all monitoring station were well below those of Standard B, EQA with the range of 0.01 mg/l 1.03 mg/l. However, due to dry season on January 2004, concentrations of free chlorine increased rapidly and several monitoring stations are not in compliance with the standard. (Table 10). (x) Phenol Phenols are aromatic hydrocarbons with hydroxy groups attached to the aromatic ring. Its concentration is usually higher in industrial wastewater than to natural waters. The permissible concentration of phenol in Standard B, EQA (1974) is 1.0 mg/l. During wet season on November 2003, MS 7 shows very high values of phenol with the range of mg/l 101 mg/l. Concentrations of Phenol in MS 7 (2.15 mg/l mg/l) during December 2003 show it never in compliance with the standard. MS 8 also have high concentration throughout December 2003 with the range of 0.2 mg/l 7.55 mg/l. Throughout January 2004, several monitoring stations are not in compliance with the standard especially MS 7 which is contaminated with very high concentration of phenol (Table 11). 462

10 Table 7 Oil and Grease. Oil and grease MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS Standard B, EQA 1974 limit: Oil and Grease = 10.0 mg/l Table 8 Sulphide. Sulphide MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS Standard B, EQA 1974 limit: Sulphide = 0.5 mg/l Table 9 Boron. Boron MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS Standard B, EQA 1974 limit: Boron = 4.0 mg/l 463

11 Table 10 Free Chlorine. Free Chlorine MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS Standard B, EQA 1974 limit: Free Chlorine = 2.0 mg/l Table 11 Phenol Phenol MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS MS Standard B, EQA 1974 limit: Phenol = 1.0 mg/l 7 Conclusions From the discussions above, it can be concluded that the water samples collected in November 2003, December 2003 and January 2004 in general are polluted with high concentration of pollutants. Even though this study was carried out during wet season with rainfall depth in the range of 79mm 220mm, the results show that there is less or may be no self-purification process and dilution occured. Most of the pollutants in monitoring stations exceed the permitted value in Standard B, EQA Acknowledgment The authors would like to express sincere gratitude to Seberang Perai Municipal Council (MPSP) for funding for this project. The authors also would like to thank Mr. Paker Mohamad, Mr Rahim Ghazali and all REDAC s staff for their involvement in this project. References 1. Seberang Perai Municipal Council. (2000). Draf Rancangan Tempatan Butterworth Seberang Perai Municipal (2004). Feasibilities Study and Drainage Improvement Work at Perai Industrial Complex, Seberang Perai Tengah, Penang. 3. Department of Irrigation and Drainage Malaysia. (1991). Hydrological Data, Rainfall Records