A leachate quality at Pulau Burung, Kuala Sepetang and Kulim landfills - A comparative study

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1 A leachate quality at Pulau Burung, Kuala Sepetang and Kulim landfills - A comparative study Hamidi Abdul Aziz *, Mohd Suffian Yusoff, Shuokr Qarani Aziz, Muhammad Umar, and Mohammed J.K Bashir School of Civil Engineering, Engineering Campus, Universiti Sains Malaysia, Nibong Tebal, Penang, Malaysia Tel: Fax: Abstract cehamidi@eng.usm.my This paper reviews, analyses and compares results of leachate composition at three landfills in the northern region; Pulau Burung sanitary landfill representing a semi-aerobic site, Kuala Sepetang landfill representing a large anaerobic landfill and Kulim landfill representing a small anaerobic landfill. Fresh samples were collected and analyzed for various physical, chemical and biological characteristics. The parameters include ph, turbidity, colour, total solids, suspended solids, biochemical oxygen demand (BOD), chemical oxygen demand (COD), BOD/COD, ammonia, ortho-phosphorus, sulfide, zinc, iron, total coliform and E.coli. The average values of some parameters such as ph (8.12, 8.6, and 7.47), turbidity (2221, 530, and 2057 FAU), colour (3763, 3670, and 4147 Pt Co), suspended solids (1511, 420, and 510 mg/l), BOD (253, 98, and 655mg/L), COD (803, 1500, and 1491mg/L), ammonia-n (457, 725, and 339 mg/l NH3-N), total iron (3.3, 5.23, and 2.9 mg/l Fe) and total coliform (<50, 0.14X10 4, and 0.81X10 4 ) for leachate at Pulau Burung, Kuala Sepetang, and Kulim Landfills were recorded, respectively. The results of these tests together with data obtained by previous researchers were compared with the Malaysia Environmental Quality Act In general, the concentrations of leachate contaminants at the Kulim site are greater than the Pulau Burung and Kuala Sepetang sites. Keywords: Solid waste, landfill, leachate, semi-aerobic, anaerobic Introduction Landfills are the most prevalent means of solid waste elimination in most countries nowadays. Though advantageous in many ways, the production of leachate in these landfills is the major drawback of this method of solid waste disposal. Landfill leachate is aqueous effluent produced when water percolates through the waste in a landfill. Precipitation, surface run-off and the infiltration of inherent water and impurities within waste by groundwater are potential sources of water entering the landfill. Leachate is known to be a highly complex liquid 1 which may contain high concentrations of organic matter (biodegradable and nonbiodegradable), ammonia nitrogen, heavy metals, chlorinated organic and inorganic salts (Renou et al., 2008). The treatment of hazardous constituents of leachate before discharge is a legal requirement to prevent pollution of water resources and to avoid both acute and chronic toxicity. The generation and composition of leachate is a function of several factors such as type of waste and composition, precipitation, age of the landfill and seasonal variations. Leachate composition

2 exhibits great temporal and site specific variations with concentrations of contaminants ranging over several orders of magnitude (Deng and Englehardt, 2006). According to Baig et al. (1999) the age of the landfill is the major influential factor which affects leachate composition. Young landfills constitute a greater fraction of biodegradable organic compounds resulting in rapid fermentation to produce volatile fatty acids (VFA) as the major fermentation product. This phase is termed as the acidogenic phase with release of free VFA up to as much as 95% of the organic content (Renou et al., 2008). As the landfill matures, the acidogenic phase is replaced by the methanogenic phase characterized by high methane production. In the methanogenic phase, leachate is rich in refractory organics which are difficult to degrade by microorganisms. In Malaysia, there are over 200 landfills, mostly old dumpsites. Most of these sites are simply dumping grounds that are without any environmental protection. The resulting leachate is discharged directly into the water courses without any treatment. This may cause severe pollution to the receiving water bodies, particularly in the cases where landfills are located at the upstream of water intakes. Quite a number of works have been undertaken to characterize leachate at various landfills in Malaysia. Most of them are site specific. This paper reviews, analyses and compares results of leachate compositions at three landfills in the northern region namely Pulau Burung sanitary landfill representing a semiaerobic site, Kuala Sepetang Landfill, representing a large anaerobic landfill and Kulim Landfill representing a small anaerobic landfill. Landfill leachate composition is usually described in terms of BOD, COD, the BOD/COD ratio, ph, suspended solids, ammonium nitrogen (NH 3 -N), total 2 Kjeldahl nitrogen (TKN), and heavy metals. In this work, samples were collected and analyzed for various physical, chemical, and biological characteristics. The parameters include ph, turbidity, colour, total solids, suspended solids, BOD, COD, BOD/COD, ammonia, ortho-phosphorus, sulfide, zinc, iron, total coliform and E.coli. The obtained results of the tests together with data published by previous researchers were compared with the Malaysia Environmental Quality Act Materials and methods 1- Samples of leachate Leachate samples were collected from three various landfills at northern region of Malaysia i.e. Pulau Burung sanitary landfill, Kuala Sepetang landfill, and Kulim landfill. The samples were collected during May and June Leachate samples were taken to the laboratory and stored in a cold room at 4 C prior to use for experimental purposes to minimize biological and chemical reactions (APHA, 2005). The samples were characterised in terms of ph, turbidity, colour, total solids, suspended solids, BOD, COD, BOD/COD, ammonia, ortho-phosphorus, sulfide, zinc, iron, total coliform and E.coli. These parameters were measured according to the Standard Method of Water and Wastewater (APHA, 2005) 2- Site characteristics i- Pulau Burung landfill Pulau Burung landfill site (PBLS) is situated within Byram Forest Reserve at 5º 24' N Latitude, 100º 24' E Longitude in Penang, Malaysia which is approximately 20 km southeast of Penang Island (Aghamohammadi et al., 2007). The total landfill site area is 63.7 ha, but only 33 ha are currently operational in receiving 2200

3 tons of solid waste daily. This site was developed as a semi-aerobic sanitary landfill Level II by establishing a controlled tipping technique in Later in 2001, it was upgraded to a sanitary landfill Level III by using controlled tipping with leachate recirculation (Gafari et al., 2009; Aziz et al., 2004). This site has a natural marine clay liner. The site was developed semi-aerobically and is one of the only three sites of its kind in Malaysia. PBLS landfill produces a dark black green colored liquid which can be classified as stable leachate with high concentrations of COD and ammonium and low BOD/COD ratio (Bashir et al., 2009; and Aziz et al., 2007). ii- Kuala Sepetang landfill Kuala Sepetang landfill is located at 4.49'.20.08" N and '.44.08" E near the town of Taiping, Perak, Malaysia. The total area of the landfill is 12.0 ha and it is equipped with a leachate collection pond. In 2007, the landfill received about 300 tons of solid waste daily. Kuala Sepetang landfill is classified as an improved anaerobic landfill. The landfill is more than 10 years old. Some recycling is practiced at the site, mainly by scavengers, then the remaining waste is dumped in individual phases. Local sand is used as cover material for dumped waste. The leachate is collected on pools which act as detention ponds. However, no further treatment is done (Abu foul, 2007). iii- Kulim landfill Kulim landfill is situated in the town of Kulim, Kedah, Malaysia. Its geographical coordinates are 5 o 25' N and 100 o 37' E. It is surrounded by a palm oil plantation. The total area of the landfill is 56 ha and it is equipped with leachate collection facilities. It is an open dumping site that started operations in 1996, and was upgraded to sanitary landfill in Study procedures Physical and chemical properties of leachate samples from each site were measured in terms of ph, turbidity, colour, total solids, suspended solids, BOD, COD, BOD/COD, ammonia, ortho-phosphorus, sulfide, zinc, iron, and total alkalinity. The characteristics of the leachate samples are shown in Table 1. 3

4 Table 1: Characteristics of raw leachate at Pulau Burung, Kamunting and Kulim landfills No. Parameter Pulau Burung Site Kuala Sepetang Site b Kulim Site Standard B Range Average a Range Average Range Average a Discharge limit c 1 ph Turbidity (FAU) Colour (Pt Co) Total solids (mg/l) Suspended solids (mg/l) BOD ( mg/l) COD (mg/l) BOD/COD Ammonia-N (mg/l NH 3 -N) Ortho-Phosphorus (mg/l) Sulfide (mg/l S 2- ) (Sulphate) 186 (Sulphate) Total iron ( mg/l Fe) Zink ( mg/l Zn) Total coliform <50.12x x x x x x E-Coli x x x x10 4 a Average value of three samples b Reference (Abu foul, 2007) c Standard B of the Environmental Quality (Sewage and Industrial Effluents) Regulations 1979, under the Environmental Quality Act of Malaysia, 1974 (Abu foul, 2007; Aghamohammadi et al., 2007; and Aziz et al., 2007) Results and discussion The characteristics of the leachate samples are given in Table 1. The parameters hereunder discussed are: ph, turbidity, colour, total solids, suspended solids, BOD, COD, BOD/COD, ammonia, ortho-phosphorus, sulfide, zinc, iron, total coliform and E.coli. 1- ph The average ph values for leachate at Pulau Burung, Kuala Sepetang, and Kulim Landfills were 8.12, 8.6 and 7.47 respectively. The present ph figures agree with (Zhong et al., 2009; Salem et al., 2008; and Bagchi, 1990). A lower ph range was recorded by Jokela et al., (2002). ph varies according to the age of landfills. For new landfills (less than two years), ph values are between 4.5 to 7.5, while for mature landfills (greater than ten years), ph varies from 6.6 to 7.5 (Tchobanoglous et al. 1993). The measured ph values remain within the allowed limit (5.5-9) of the Environmental Quality (Sewage and Industrial Effluents) Regulations 1979, under the 4 Environmental Quality Act of Malaysia, 1974 (Abu foul, 2007; Aghamohammadi et al., 2007; and Aziz et al., 2007). 2- Turbidity Ranges of FAU, FAU, and FAU were recorded for turbidity at Pulau Burung, Kuala Sepetang and Kulim landfills respectively. It was noticed that the leachate at the Pulau Burung site contains higher turbidity than the others, due to the age of the landfill (more than 20 years) and stabilization of leachate. Bagchi (1990) reported that the turbidity of leachate ranged from 40 to 500 JU. For semiaerobic (intermittently aerated) leachate at PBLS, two different turbidity ranges FAU and FAU were obtained by researchers (Gafari et al., 2009; and Aghamohammadi et al., 2007). It is observed that turbidity values of aerated leachate is higher than intermittently aerated leachate.

5 3- Colour The minimum values of colour at PBLS, Kuala Sepetang, and Kulim were 3500, 2500, and 2360 Pt Co, respectively, while the maximum values were 4050, 5000, and, 5230 Pt Co. For semi-aerobic PBLS (intermittently aerated leachate), similar ranges were recorded by previous researchers Pt Co and Pt Co (Gafari et al., 2009; and Aghamohammadi et al., 2007); but a wider range pt Co was recorded by Aziz et al. (2007). 4- Total solids Total solids represent dissolved and suspended solids. The average values of total solids for PBLS (anaerated) and Kulim sites were 7017 mg/l and 5814 mg/l, respectively. The sum of total dissolved solids and total suspended solids of typical leachate ranged between 586 mg/l to mg/l (Bagchi, 1990). The present values remain within this range. A smaller figure 1140 mg/l was recorded by (Salem et al., 2008). 5- Suspeded solids The average values of suspended solids (SS) at PBLS, Kuala Sepetang, and Kulim were 1511, 420, and 510 mg/l, respectively. The typical ranges of TSS in leachate for new landfills (< 2 years) and mature (> 10 years) landfills are and mg/l (Tchobanoglous et al. 1993). A wide range of mg/l was recorded for typical leachate by Bagchi (1990). Smaller SS values of 133 mg/l, mg/l, mg/l were reported for semi-aerobic PBLS leachate (intermittently aerated) by previous researchers (Bashir et al. 2009; Gafari et al. 2009; and Aghamohammadi et al. 2007). It is noticed that aeration has an affect on the decrease of SS in leachate. The obtained SS values are greater than the allowed level 100 mg/l (Abu foul, 2007; Aghamohammadi et al., 2007; and Aziz et al., 2007). 6- BOD BOD is the most widely used parameter of organic pollution applied to both wastewater and surface water. Determination of BOD involves the measurement of dissolved oxygen used up by microorganisms in the biochemical oxidation of organic matter. The standard 5-day BOD value is commonly used to determine the amount of organic pollution in water and wastewater (Metcalf and Eddy, 2003; and Warren Viessman and Hammer, 1985). In this study, the maximum range of BOD mg/l was recorded at the Kulim Site, while the minimum range was mg/l, recorded at the Kuala Sepetang Site. BOD 5 varies with the age of the landfill. Tchobanoglous et al. (1993) explained two different ranges, mg/l and mg/L, for both new and mature landfills respectively. Four phases: transition( 0-5 years), acid formation (5-10 years), methane fermentation (10-20 years), and final maturation ( > 20 years) were presented by (Kostova, 2006); the range of BOD for each phase is mg/l, mg/l, mg/l, and mg/l, respectively (Kostova, 2006). The present values of BOD agree with those recorded by (Salem, 2008; Aghamohammadi et al. 2007; Aziz et al, 2007; Rushbrook and Pugh, 1999; Bagchi, 1990). Greater BOD figures of 2950 mg/l and mg/l were explained by (Canziani, et al., 2006; and Weiner and Matthews, 2003). According to Malaysian standards, the permissible level of BOD is 50 mg/l. The measured BOD values greater than the permissible level of 50 mg/l were also reported in other studies (Abu foul, 2007; Aghamohammadi et al., 2007; and Aziz et al., 2007). 5

6 7- COD The average COD values for leachate at PBLS, Kuala Sepetang, and Kulim were 803, 1500 and 1491 mg/l, respectively. COD values for new and mature landfills ranged from 3000 to mg/l and 100 to 500 mg/l, respectively (Tchobanoglous et al. 1993). The present results are greater than the mentioned ranges. But according to Kostova (2006), the present COD results remain within the mentioned ranges. Also, the COD values recorded by Jokela et al., (2002) agree with the present COD values. Greater COD values were reported by other researchers (Zhong et al., 2009; Ziyang et al., 2009; Salem et al., 2008; Canziani, et al., 2006; Weiner and Matthews, 2003; and Rushbrook and Pugh, 1999). The obtained COD values are greater than the allowed limit of 100 mg/l as recorded by others (Abu foul, 2007; Aghamohammadi et al., 2007; and Aziz et al., 2007). 8- BOD/COD The BOD/COD values for collected leachate samples ranged between 0.12 and 0.41, 0.05 and 0.06, and 0.35 and 0.78 at PBLS, Kuala Sepetang, and Kulim sites, respectively. The low BOD/COD ratio indicates that the leachate is stable and difficult to be further biologically degraded (Jokela, et al., 2002 as cited by Abu foul, 2007). Results ( ) published by previous researchers confirm the present ranges of BOD/COD at PBLS and Kulim Site (Salem et al., 2008; Aghamohammadi et al., 2007; Aziz et al., 2007; Canziani et al., 2006; and Weiner and Matthews, 2003). But a lower figure of was measured by Bashir et al, (2009). Generally, the BOD/COD of wastewater is greater than of leachate due to stabilization of leachate; BOD/ COD 0.7 for wastewater (Bartram and Balance, 1996). Aziz (2004) studied the characteristics of Erbil wastewater throughout one year and found that the 6 BOD/COD value was equal to Generally, the measured BOD/COD values are less than the minimum allowed level of 0.5 (Abu foul, 2007; Aghamohammadi et al., 2007; and Aziz et al., 2007). 9- Ammonia The average values of ammonia for leachate at PBLS, Kuala Sepetang, and Kulim sites were 457 mg/l, 725 mg/l, and 339 mg/l, respectively. A similar value of 500 mg/l was published by (Weiner and Matthews, (2003). Some researchers reported greater figures of 1400 mg/l, mg/l, and 1200 mg/l (Aghamohammadi et al., 2007; Rushbrook and Pugh, 1999; and Bagchi,1990). The ranges of mg/l and mg/l were explained for new and mature landfills (Tchobanoglous et al. 1993). 10- Ortho-phosphorus Phosphorus in wastewater is present predominantly in the form of (ortho) phosphates, with a minor fraction of organic phosphate, mainly in proteins. In biological treatment systems, most of the organic phosphate is mineralized (Cervantes et al., 2006; and Baftens, 2001). Ortho-phosphorus values of leachate at the PBLS and Kulim Site vary from 84 to 274 mg/l and 57 to 91 mg/l, respectively. According to Tchobanoglous et al. (1993), the typical values of orthophosphorus for new and mature landfills were 20 mg/l and 4-8 mg/l; the present values are greater than those reported by Tchobanoglous et al. (1993). Also, a smaller range mg/l for landfill leachate was published by Ziyang et al., (2009).

7 11- Sulfide The average values of sulfide at the PBLS and Kulim sites were 0.75 mg/l S 2-, and 1.11mg/LS 2-, respectively. For the Kuala Sepetang site, the average value of sulphate was 186 m/l (Abu foul, 2007); this value agrees with the reported data (100 mg/l) by (Aghamohammadi et al., 2007). For new and mature landfills, the sulphate values are 300 mg/l and 20 to 50 mg/l, respectively (Tchobanoglous et al., 1993). Other greater figures (3056 mg/l and 1850 mg/l) were published by (Salem et al., 2008; and Bagchi 1990). 12- Total iron Total iron values vary from 2 to 4.6 mg/l, 3.5 to 8 mg/l, and 1.9 to 3.9 mg/l for PBLS, Kuala Sepetang, and Kulim landfill leachate respectively. Aziz s et al., 2007 results ( mg/l) confirm the present results. But greater ranges of mg/l and 500 mg/l were published by other researchers (Aghamohammadi et al., 2007; and Weiner and Matthews, 2003). Total iron concentration in leachate at PBLS and Kulim Site remains within the allowed limit of 5 mg/l (Abu foul, 2007; Aghamohammadi et al., 2007; and Aziz et al., 2007). 13- Zinc The average values of zinc for the PBLS, Kuala Sepetang, and Kulim landfill leachate were 0.25 mg/l, 0.2mg/L, and 0.15 mg/l, respectively. Greater values (2.06 mg/l, mg/l, and 50 mg/l) were reported by previous researchers (Aghamohammadi et al., 2007; and Aziz et al., 2007; and Weiner and Matthews, 2003). According to Malaysian standards, the concentration of zinc in the landfill leachates remains within the acceptable level (1 mg/l) Total coliform and E.coli Coliforms are defined as including all of the aerobic and the facultative anaerobic, non spore, forming, gram-stain negative rods that ferment lactose with gas production within 48 hours of incubation at 35 o C (McGhee 1991; and Warren Viessman and Hammer, 1985). The organisms originating from the intestinal tract of warm blooded animals are called E.coli (Bartram and Balance, 1996). The PBLS landfill site contains a negligible number of total coliform (< 50), and no E.coli was found primarily because of a high salt concentration of 14% as recorded by Umar et al (2009). The activity of E.coli is known to be inhibited by salt concentrations of higher than 9% (Tassoulae 1997). The Kuala Sepetang landfill contains a higher concentration of total coliform and E.coli ranging between to and , respectively. The Kulim landfill site has the highest concentration of total coliform and E.coli ranging between 0.77 to and to , respectively. There are no standards available for total coliform and E.coli concentrations for discharged wastewaters. Variations in the concentrations of these organisms are perhaps because of the characteristics of waste, landfill age and waste handling practices at landfill sites. Conclusions and recommendations The following conclusions can be outlined from the present research: 1-Anaerobic leachate ponds contain high concentrations of dissolved and suspended matters. Since the concentrations of SS, BOD, COD, Iron and Zinc are greater than the standards, the leachate requires treatment to minimize pollutants to a desirable level prior to discharge into water courses. Several treatment processes are used to treat leachate such as aerobic and anaerobic biological degradation,

8 chemical oxidation, chemical precipitation, coagulation-flocculation, activated carbon adsorption and membrane processes (Bashir, 2007). 2- The concentration of pollutants in a Semi-aerobic landfill (Pulau Burung) is lesser than the others (Kuala Sepetang and Kulim landfills). Thus, it is recommended for landfills to be designed as semi-aerobic instead of anaerobic. 3- According to parameter measurements i.e. turbidity, colour, suspended solids, and ammonia, the concentration of materials in semi-aerobic (intermittently aerated) leachate at PBLS is lesser than in semiaerobic (unaerated) leachate (Gafari et al., 2009; and Aghamohammadi et al., 2007). It can be concluded that aeration reduces turbidity, colour, suspended solids, and ammonia. 4- Generally, the concentrations of leachate contaminants at the Kulim site are greater than the other sites. 5- High ph (on average 7.84), low COD concentration (<2000 mg COD/L), low BOD/COD ratio (<0.4) and low heavy metal concentration indicate that the landfills (PBLS and Kuala Sepetang Site) were already characterized by methanogenic conditions at the beginning of the monitoring period (Kulikowska and Klimiuk, 2008; Tchobanoglous, et al., 1993; and Abu foul, 2007). References Abu foul, A.E.M. (2007). Physicalchemical treatment of stabilized leachate using limestone, activated carbone and zeolite. Unpublished, PhD thesis. School of Civil Engineering, University Sains of Malaysia. Aghamohammadi N., Hamidi A.A, Hasnain I. M., Zinatizadeh A. A., Nasrollahzadeh S.H., and Ghafari S. (2007). Performance of a Powdered 8 Activated Carbon (PAC) Augmented Activated Sludge Process Treating Semi- Aerobic Leachate, Int. J. Environ. Res. 1, APHA, (2005). Standard Methods for the Examination of Water and Waste Water, 21 st edition. American Public Health Association, Washington, DC. Aziz H.A., Adlan M.N., Zahari M.S.M., and Alias S. (2004). Removal of ammoniacal nitrogen (N NH 3 ) from municipal solid waste leachate by using activated carbon and lime stone, Waste Manage. 22, Aziz H.A., Alias S., Adlan M.N., Asaari F.A.H., and Zahari M.S.M. (2007). Colour removal from landfill leachate by coagulation and flocculation processes. Bioresource Technology 98, Aziz Sh.Q. (2004). Seasonal variation of some physical and chemical properties of water and wastewater in Erbil City. Journal of Dohuk Univ. Vol. 7 No.2. Baftens D. (2001). Enhanced biological phosphorus removal: Modelling and experimental design. PhD thesis. Dept. of Tech. Chem. and Env. Eng., Ghent Univ., Belgium. Bagchi, A. (1990). Design, construction, and monitoring of sanitary landfill. First edition. John Wiley & Sons, Inc. Baig S., Coulomb I., Courant P., and Liechti P. (1999). Treatment of landfill leachates; Lapeyrouseand Satrod case studies. Ozone Sci. Eng. 21, Bartram and Balance. (1996). Water Quality Monitoring a Practical Guide to the Design and Implementation of Fresh Water Quality Studies and Monitoring Programs. by E and FN, an imprint of Chapman & Hall, 1st edition.

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