POST-TREATMENT OF PALM OIL MILL EFFLUENTUSING MODIFIED SEQUENCING BATCH REACTOR AUGMENTED WITH ZEOLITE
HOSSEIN FARRAJI
UNIVERSITI SAINS MALAYSIA
2018
POST-TREATMENT OF PALM OIL MILL
EFFLUENT USING MODIFIED SEQUENCING
BATCH REACTOR AUGMENTED WITH ZEOLITE
by
HOSSEIN FARRAJI
Thesis submitted in fulfillment of the requirements for the degree of
Doctor of Philosophy
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ACKNOWLEDGEMENT
All praises are due to the Creator without Whom I wouldn’t have finished this Ph.D. research work. Firstly, I would like to express my sincere gratitude to my supervisor Associate Prof Dr. Nastaein Qamaruz Zaman for the continuous support of my study and related research, for her patience and motivation.
Besides my advisor, I would like to thank my co-supervisors, Prof. Dr. Hamidi Abdul Aziz, and Dr. Mohammad Aqeel Ashraf for their insightful comments and encouragement. I also would like to thank Dr. Amin Mojiri, Dr. Ali Arab, Mr. Parsa Mohajeri and Dr. Amirhossein Vakili for their encouragement and support especially at times when things were going very tough. I would also thank all lab technicians, as without their wise knowledge and assistance this study would not have been successful. This research was funded by the iconic ‘Grant for Research Associated with the Solid Waste Management Cluster’ (Grant no. 1001/CKT/870023), Engineering campus, Universiti Sains Malaysia. Finally, I must express my very profound gratitude to my mother for providing me with unfailing support and continuous encouragement throughout my life. My honest appreciate to my family for their patient and support. At last but not the least, my brother Dr. Hamed Faraji and my brother in law Mr. Smaeil Jafari who their continuous support and supplies helped me. This acknowledgement will not be fair without superior thanks and appreciate Mr. Taib yacob, the person who spend a major part of his time for teaching skills and improving creative thinking through the designing and manufacturing several types of reactors as well as a brother.
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TABLE OF CONTENTS
Page
ACKNOWLEDGEMENT ii
TABLE OF CONTENTS iii
LIST OF TABLES ix
LIST OF FIGURES xi
LIST OF ABBREVIATION xiv
LIST OF SYMBOLS xvi
ABSTRAK xvii
ABSTRACT xix
CHAPTER ONE - INTRODUCTION
1.1 Overview 1
1.2 Problem statement 2
1.3 Research Objectives 4
1.4 Scope of Study 4
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CHAPTER TWO - LITERATURE REVIEW
2.1 Palm Oil Production 6
2.2 POME as an Agro-industry Wastewater 7
2.3 Characteristics of POME 8
2.3.1 Total Suspended Solids (TSS) 12
2.3.1(a) Volatile Suspended Solid (VSS) 13 2.3.2 Biological Oxygen Demand (BOD) 13
2.3.3 Chemical Oxygen Demand (COD) 14
2.3.4 Color 158
2.3.5 Ammonia and total nitrogen 16
2.3.6 Phosphorus 17
2.4 Biodegradability of POME 20
2.5 POME Treatment Methods 22
2.5.1 Commercial Treatment Method 22
2.5.1(a) Ponding Treatment 22 2.5.1(b) Continuously Stirred Tank Reactor 23 2.5.1(c) Anaerobic Digestion for Methane Production 23 26 2.5.2 Non-commercial Treatment Methods
2.6 SBR as a POME Treatment System 27
2.6.1 SBR System 27
2.6.1(a) Fundamental and Mechanism of SBR Treatment Process
30
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2.6.2(a) Simple Construction 32
2.6.2(b) Combination Ability 33 2.6.2(c) Augmentation and Specific Treatment 34 2.6.2(d) Wide Range of Application 34 2.6.3 The Application of the SBR in POME Treatment 35 2.6.3(a) Factors Affecting SBR System 37 2.6.3(b) Microbial Augmentation for POME 38 2.6.3(c) Adsorbent Augmentation 39
2.7 Response Surface Method (RSM) 42
2.8 Summary 45
CHAPTER THREE - MATERIALS AND METHODS
3.1 Introduction 46
3.2 Case Study Sites 49
3.2.1 Site Description and POME Sampling 49 3.2.2 Site Description and Municipal Wastewater Sampling 50
3.3 Design of Sequencing Batch Reactor 51
3.3.1 SBR Operating 54
3.3.1(a) Different between LL and POME 55
3.4 Zeolite 57
3.4.1 Characterization of zeolite 58
3.4.2 Determination of Zeolite Dosage 59
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3.6 Determination of Settling Time 61
3.7 Optimization of RSM 61
3.7.1 Validation of RSM Prediction 66
3.8 Efficiency of Removal 67
CHAPTER FOUR - RESULTS AND DISCUSSIONS
4.1 Introduction 69
4.2 Characteristics of the POME, MWW and Zeolite 69
4.2.1 Characteristics of POME 69
4.2.2 Characteristics of Municipal Wastewater 70 4.2.3 Characteristics of Zeolite before Treatment 71 4.2.4 Zeolite Characteristics after Pollutant Loading 79 4.2.4(a) Mineral Characteristics 79
4.2.4(b) Microbial Content 85
4.3 Identification of Suitable Zeolite Dosage using Batch Tests 87
4.3.1 Settling Time 90
4.4 Establishment of Optimum Operating Conditions for the Modify SBR System
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4.4.1 TSS Removal 92
4.4.1(a) Turbidity Removal 94
4.4.2 BOD Removal 96
4.4.3 COD Removal 98
4.4.4 Color Removal 101
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4.4.6 Ammonia Nitrogen Removal 105
4.4.7 Total Phosphorus Removal 107
4.5 Mechanism of Pollutants Removal by Zeolite 108
4.5.1 Introduction 108
4.5.2 Ion Exchange Capacity 110
4.5.3 Bridge Mechanism 111
4.5.4 Surface Adsorption 113
4.5.5 Micro-Pollutants 113
4.6 The Role of Municipal Wastewater in the Treatment Mechanism 114
4.7 Biodegradation 115
4.7.1 Total Count and E.coli 116
4.8 Adsorption 117
4.8.1 Macro Pollutants 118
4.9 Summary of Removal Mechanisms 119
4.10 Continuous Experimental Results 119
4.11 Establishment of Prediction RSM Model for POME Treatment 123
4.11.1 TSS Removal 123
4.11.2 COD Removal 125
4.11.3 Nitrogen Removal 128
4.11.4 Biodegradability 129
4.11.4.a Discussion on pollutant removal 134
4.11.5 Desirability 135
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4.12 Recommended Economical SBR Operating 139
CHAPTER FIVE - CONCLUSION AND RECOMMENDATIONS
5.1 Conclusions 141
5.2 Recommendation for Future Studies 143
REFERENCES
APPENDICCES
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LIST OF TABLES
Page Table 2.1 World's vegetable oil critical specifications 6 Table 2.2 World's main palm oil production countries 7 Table 2.3 Different agroindustry wastewater characteristics 8
Table 2.4 The centrifugal fraction of POME 9
Table 2.5 Characteristics of raw POME 19
Table 2.6 Characteristics of raw POME, Malaysian discharge standards and required efficiency for passing discharge standards
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Table 2.7 The effectiveness of aerobic SBR treatment for POME 36 Table 2.8 Characteristics of natural zeolite in literature 39 Table 2.9 Summary of natural zeolite application for POME treatment in
literature
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Table 3.1 Characteristics of Landfill leachate and POME 56
Table 3.2 Actual values for variable factors 64
Table 3.3 Experimental variable factors for SBRs 65 Table 4.1 Characteristics of anaerobically treated POME and Malaysian
discharge standards
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Table 4.2 Characteristics of MWW collected for this study 70 Table 4.3 Weight and atomic percentage of natural zeolite elements 75 Table 4.4 XRF characteristics of the natural zeolite 77 Table 4.5 BET test results in natural zeolite before treatment 78 Table 4.6 ICP characteristics of raw POME before treatment 79
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Table 4.7 Weight and atomic percentage of zeolite elements after treatment
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Table 4.8 BET test results in natural zeolite after treatment 85
Table 4.9 ICP results of treated POME 85
Table 4.10 Total count and E.coli in treated SBR system 86 Table 4.11 Operation conditions and TSS removal performance 94 Table 4.12 Operation conditions and turbidity removal performance 96 Table 4.13 Operation conditions and BOD5 removal performance 98
Table 4.14 Operation conditions and COD removal performance 101 Table 4.15 Operation conditions and color removal performance 103 Table 4.16 Operation conditions and total nitrogen removal performance 105 Table 4.17 Operation conditions and ammonia nitrogen removal
performance
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Table 4.18 Operation conditions and total phosphorus removal performance 108 Table 4.19 Operation factors and results of selected responses in continuous
test
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Table 4.20 Experimental condition and results of collected responses for RSM modeling
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Table 4.21 ANOVA results for the equation of the Design Expert 10.0.3 for collected responses
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Table 4.22 Efficiency report for desirability in different operations, targets, and other responses
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Table 4.23 Economic SBRfor achieving the highest efficiency in the lowest cost of operation factors
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LIST OF FIGURES
Page Figure 2.1 Particle size distribution data for raw POME 10 Figure 2.2 Figure 2.2: PSA system of POME (Khanam et al., 2016) 11 Figure 2.3 Biodegradability line for wastewater (Metcalf and Eddy,
2014) and collected biodegradability in previous studies on POME, COD, and BOD
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Figure 2.4 Process Flow Diagram of anaerobic digestion 24
Figure 2.5 SBR operation for one cycle 29
Figure 2.6 SBR 32
Figure 3.1 Flowchart of the methodology 48
Figure 3.2 Aerial view of the UOPM 49
Figure 3.3 Anaerobically treated POME sampling (Pond number 8) 50
Figure 3.4 Municipal wastewater sampling point 51
Figure 3.5 Schematic characteristics of SBR with CBA system, air pump, and air flow meter
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Figure 3.6 All 20 SBR reactors running simultaneously in same environmental condition
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Figure 3.7 Batch test process and optimum dosage of adsorbent 60
Figure 4.1 SEM micrograph of natural zeolite 74
Figure 4.2 Element content (EDS mapping) before treatment in natural zeolite structure (a:Oxygen, b:Aluminum, c:Silicon,
d:Carbon, and e:Magnesium)
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treatment
Figure 4.4 SEM micrograph of a pollutant-loaded natural zeolite (a:10000, b:20000, and c: 35000 magnified )
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Figure 4.5 Element content (EDS mapping) after treatment in natural zeolite structure (a:Oxygen, b:Aluminum, c:Silicon, d:Carbon, and e:Magnesium)
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Figure 4.6 Zeolite spectrum (EDS of the plotted area) after treatment 84 Figure 4.7 Removal efficiency of ammonia, COD, TSS, TP, and color
in batch test against zeolite dosage
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Figure 4.8 Anaerobically treated POME and 11g/L dosage zeolite treatment in batch study
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Figure 4.9 Effect of settling time on concentration of dissolved oxygen in modify SBR
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Figure 4.10 The 3D surface plots and 2D contour plot for TSS removal 124 Figure 4.11 Predicted vs. Actual contour plot for TSS removal 125 Figure 4.12 The 3D surface plots and 2D contour plot for COD removal 126 Figure 4.13 Predicted vs. Actual contour plot for COD removal 127 Figure 4.14 The 3D surface plots for total and ammonia nitrogen removal
(contact time of 12 h)
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Figure 4.15 The 3D surface plots and 2D contour plot for biodegradability
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Figure 4.16 Two-dimensional plot count of highest desirability in operation considering TSS, BOD, COD, and color as target pollutants
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Figure 4.17 Two-dimensional plot count of engineered desirability operation considering TSS, BOD, COD, and color as target pollutants (minimum aeration).
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LIST OF ABBREVIATIONS
BET Brunauer-Emmer-Teller BOD Biological Oxygen Demand CCD Central Composite Design CEC Cation Exchange Capacity cfu Colony Forming Units
COD Chemical Oxygen Demand
CPO Crude Palm Oil
HDPE High Density Polyethylene
MLVSS Mixed liquor volatile suspended solids
MNDWQS Malaysian National Drinking Water Quality Standards MWW Municipal Wastewater
NG Not Given
Neg Negative
POME Palm Oil Mill Effluent PSA Particle Size Analyze
Rem Removal
rpm Round Per Minute
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SBR Sequencing Batch Reactor SSA Specific Surface Area
SEM Scanning Electron Microscope
SERC Science and Engineering Research Centre TDS Total Dissolved Solids
TN Total Nitrogen
TP Total Phosphorus
TS Total Solids
TSS Total Suspended Solids
UASB Up flow Anaerobic Sludge Blanket
UNFCCC United Nations Framework Convention on Climate Change Program
UOPM United Oil Palm Mill
USDA United States Department of Agriculture
USEPA United States Environmental Protection Agency USM Universiti Sains Malaysia
VSS Volatile Suspended Solids
xvi LIST OF SYMBOLS µm Micrometer nm Nano meter O Oxygen H Hydrogen C Carbon Al Aluminum Fe Ferron Ca Calcium Cº Degree Celsius L Liter W Weight N North E East g Gram h Hour ha Hectare Å Angstrom R2 Coefficient of Determination
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PASCA-OLAHAN EFLUEN KILANG KELAPA SAWIT MENGGUNAKAN REAKTOR KELOMPOK PERJUJUKAN TERUBAHSUAI DITINGKATKAN
DENGAN ZEOLITE
ABSTRAK
Salah satu sistem olahan air sisa adalah penjujukan reaktor kelompok (PRK). Pasca olahan effluen kilang kelapa sawit (EKKS) dengan aplikasi air sisa bandar dan penggunaan zeolit semulajadi dalam sistem PRK aerobic terubahsuai. EKKS mengandungi kepekatan pencemar organik yang sangat tinggi, kepekatan elemen logam toksik yang rendah bersama kandungan mikrob yang rendah. Aplikasi terus air sisa bandar sebagai pembekal mikrob dan zeolite sebagai penggumpal semulajadi dalam PRK diubahsuai dijalankan bagi menghapuskan aklimitasi enapcemar bagi menjimatkan kos dan masa operasi melalui proses aerobik. Pengudaraan digunakan untuk mengadun dan sebagai sumber oksigen dalam sistem PRK. Kajian kelompok dijalankan dengan 5, 10, 15, 20, 25, 30 dan 35 g/L zeolite. 15 g/L zeolite dikenalpasti sebagai dos yang optimum. Zeolit semulajadi yang digunakan mempunyai saiz dari 75 µm to 150 µm. Kaedah Permukaan Tindak Balas (RSM) dan Rekabentuk Komposit Pusat (CCD) digunakan bagi mendapatkan keadaan operasi optimum (pembolehubah bebas) bagi nisbah air sisa bandar kepada EKKS, kadar pengudaraan dan masa sentuh. Tujuh parameter dipilih sebagai pembolehubah tanggungan (respons) iaitu Jumlah Pepejal
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Terampai, Keperluan Oksigen Biologi, Keperluan Oksigen Kimia, Nitrogen Ammonia, Jumlah Nitrogen dan Jumlah Fosforus. Hasil pengumpulan data menunjukkan, kaedah rawatan tunggal mampu mengolah EKKS dalam masa yang singkat tanpa memerlukan proses aklimitasi enap cemar. Dalam keadaan optimum dengan nisbah air sisa bandar kepada EKKS (58.7 v/v,%), kadar pengudaraan (6.85 L/min) dan masa sentuh (17.9 jam) bagi PRK, keberkesanan pengurangan TSS, BOD, COD, warna, nitrogen ammonia, jumlah nitrogen dan jumlah fosforus adalah 99.16%, 90.67%, 98.4%, 84.34%, 98.33%, 96.26% dan 93.49% setiapnya. Mekanisme penyingkiran adalah melalui degradasi mikrob, penggumpalan, kapasiti penukaran kation dan penjerapan permukaan. Kesan spesifik oleh air sisa bandar melalui proses olahan mikrobiologi dengan bantuan zeolite bagi pertimbuhan mikrob dan penggumpalan bahan tidak boleh terdegradasi adalah aspek utama keberkesanan. Gabungan air sisa bandar dan EKKS ditingkatkan dengan bantuan zeolite semulajadi dalam sistem PRK terubahsuai aerobik boleh digunapakai sebagai kaedah mikrobiologi yang berkebolehan untuk rawatan EKKS dengan kos yang efektif dan dalam masa yang singkat.
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POST-TREATMENT OF PALM OIL MILL EFFLUENTUSING MODIFIED SEQUENCING BATCH REACTOR AUGMENTED WITH ZEOLITE
ABSTRACT
One of the biological treatment system for wastewater treatment is sequencing batch reactor (SBR). Post-treatment of palm oil mill effluent by direct application of municipal wastewater and augmentation of natural zeolite in aerobic modified SBR system. POME contain extremely high concentration of organic pollutants, very low concentration of toxic metallic elements, and low microbial content. Direct application of municipal wastewater as microbial supply and zeolite as natural coagulant in modified aerobic sequencing batch reactor (SBR) conducted in order to decreasing operation time and cost of operation process through the aerobic treatment. Aeration used for mixing and oxygen source in SBR system. Batch study carried out with 5, 10, 15, 20, 25, 30, and 35 g/L zeolite. 15g/L zeolite collected as optimum adsorbent dosage. The size of natural zeolite ranged from 75 µm to 150 µm. Response Surface Methodology (RSM) and Central Composite Design (CCD) were used for collecting the optimum operating conditions (independent variables) which were ratio of municipal wastewater (MWW) to POME, aeration flow and contact time. Seven parameters namely total suspended solids (TSS), biological oxygen demand (BOD5), chemical
oxygen demand (COD), ammonia nitrogen (NH3-N), total nitrogen and total phosphorus
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treatment method has capability for effective POME treatment in short time without requiring to sludge acclimatization process. In the optimum condition of municipal wastewater to POME ratio (58.7 v/v; %), aeration rate (6.85 L/min) and contact time (17.9h) for the SBR, efficiency of the reduction for TSS, BOD, COD, colour, ammonia nitrogen, total nitrogen and phosphorus were 99.16%, 90.67%, 98.4%, 84.34%, 98.33%, 96.26% and 93.49% respectively. Mechanism of removal mostly were microbial biodegradation, coagulation, cation exchangeable capacity, and surface adsorbent. Specific effect of municipal wastewater through the microbiological treatment process and assistance influence of zeolite for microbial growth and non-degradable maters coagulation are main aspects of efficiency. Combining municipal wastewater with POME and augmenting with natural zeolite in aerobic modified SBR system, could be considered as a capable microbiological method for POME in cost effective and short time treatment.
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CHAPTER ONE
INTRODUCTION
1.1 Overview
Nowadays, oil palm production in Malaysia reached to 20,000,000 tons (MPOB, 2016). Activities of 426 mills, production and by products have a positive effect on the Malaysian economy. Other side of this industry is environmental impacts of palm oil industry which means 60,000,000 tons effluent being a major concern for Malaysia as the leader of scientific researches in green improvement. Due to aforementioned facts, the palm oil industry as main agroindustry; faces a big challenge in balancing the economic viability, environmental protection and sustainable development. Thus, there is an urgent need to finding a suitable way to keep our economy growth while preserving the environment (Chin et al., 2013).
The conventional treatment method for palm oil mill effluent is ponding system which is an easy operation, time consuming process in several ponds or digesting system, with high cost operation in a big land area and environmental impacts (Mansor et al., 2017). On the other hand, this method is highly dependent to land application and rivers as final destination of effluent discharge. Unfortunately, inability of this anaerobic-aerobic method in passing discharge standards (Bhatia et al., 2007) has led to concerning on numerous scientific researches on high efficiency, cost effective, easy operation and short time treatment methods. Ponding system which has been applied in 85% of oil palm industry is the most common commercial treatment method (Poh and Chong 2009) while the remaining 15% are operated by
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using tank digestion system. Finding effective treatment method for Palm Oil Mill Effluent (POME) will be more serious when Malaysian authorities aim to strengthen standard limits to BOD5 equals to 20 mg/L (Liew et al., 2015) .
Anaerobic digestion of POME in covered ponds which known as methane production process, have positive attraction on environmental footprint by decreasing the greenhouse gas emission and methane gas collection despite the, expensive construction, high maintenance fee, operation, high land requirement caused to slow improving trend in this traditional treatment system. This method is based on the microbial activity in anaerobic circumstances on organic matter in aquatic nutrient media for methane production. Raw POME is an acidic media with temperature of 80-90 oC (Chin et al., 2013) will caused low content of microbial population. Long period of time is required for available microbial population to adapt and starting digestion process. However, low biodegradability of lignin compounds (Oswal et al., 2002), makes the digestion process longer as well as decreasing in pollutant removal efficiency and methane production. Further studies should be conducted to develop innovative methods to reduce the cost of treatment and increase treated water quality (Mansor et al., 2017).
1.2 Problem Statement
Biological treatment could be a high effective treatment method for wastewater with high biodegradability index and low concentration of non-biodegradable compound such as lignin (Pérez et al., 2002). Approximately 50 % of POME pollutants are low or non-biodegradable organic matters which should be separate from fine, easily degradable organic compound such as fatty acids by suitable coagulation mechanism (Ahmad et al., 2005a). Efficiency of pollutant removal can
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be improved using aerobic sequencing batch reactor (SBR) (Wang and Li, 2009). Augmentation of municipal wastewater is an advanced treatment technique for enhancing the efficiency of pollutant removal in strength wastewaters and often have been used in landfill leachate (Mojiri et al., 2014, Aziz et al., 2011b). Activated sludge recognized as one of the most effective aerobic treatment meanwhile, it is the least applied by oil palm mills since of its higher operation cost (Chan et al., 2010). In a SBR system sludge acclimatization is necessary for microorganisms adaptation to new condition, and it takes 10 days when treating landfill leachate (Aziz et al., 2011b). On the other hand, high concentration of ammonia nitrogen is another factor cause low efficiency of SBR treatment and high concentration of ammonia nitrogen which is very toxic for microorganisms population and gradually could be protected by sludge acclimatization process (Aziz et al., 2011b). Since POME has nontoxic properties (Rupani et al., 2010) and contain very low concentration or absence of hazardous heavy metals such as Pb and Cu (Agustin et al., 2008), Cd and Cr (Ubani et al., 2017).
The knowledge of natural adsorbent (zeolite) application in SBR for POME treatment contain some gaps and need more development. Literature indicate that single pollutant removal such as oil (Shavandi et al., 2012a) and heavy metal (Shavandi et al., 2012b) have been studied in POME which the main pollutants are BOD5, COD, TSS and color (Liew et al., 2015).
Since of two major types of pollutants (biodegradable and capable for coagulation) in POME a new finding is needed to present direct application of municipal wastewater as microbial community supplier and natural adsorbent as coagulation and microbial biofilm formation is required as a novel combined microbiological treatment method for POME in aerobic SBR system.
