UNIVERSITI PUTRA MALAYSIA

ENHANCED BIOMETHANATION OF PALM OIL MILL EFFLUENT DURING ANAEROBIC TREATMENT IN A CLOSED DIGESTER TANK

ALAWI BIN HJ SULAIMAN

FK 2010 98

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ENHANCED BIOMETHANATION OF PALM OIL MILL EFFLUENT DURING ANAEROBIC TREATMENT IN A CLOSED DIGESTER TANK

By

ALAWI BIN HJ SULAIMAN

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia, in Fulfilment of the requirements for the Degree of

Doctor of Philosophy

April 2010

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Abstract of the thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of the requirement for the degree of Doctor of Philosophy

ENHANCED BIOMETHANATION OF PALM OIL MILL EFFLUENT

DURING ANAEROBIC TREATMENT IN A CLOSED DIGESTER TANK

By

ALAWI BIN HJ SULAIMAN

April 2010

Chairman : Professor Mohd. Ali Hassan, PhD

Faculty : Engineering

The methane capture project from anaerobic treatment of palm oil mill effluent

(POME) treatment for clean development mechanism (CDM) is becoming

increasingly important due to the problems caused by the utilisation of fossil fuels

such as global warming, air and water pollution, resource depletion, high energy

price, acid rain and others. The traditional way of treating POME using large open

ponds or tanks system is an unsustainable practice because large amounts of

methane are released to the atmosphere contributing to the greenhouse gas (GHG)

emission. By closing the digester, methane could be captured and utilized to

generate electricity for internal consumption or Tenaga Nasional Berhad (TNB)

grid connection. Moreover, with CDM registration with the United Nation

Framework Convention on Climate Change (UNFCCC), the captured methane

could be converted into carbon credit and could be traded in the international

market as certified emission reduction (CER). Hence, there is an urgent

requirement for the industry to capture as much methane as possible so that higher

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CER and electricity power could be generated to partly finance the overall project

cost. For this purpose there is an urgent need to understand the various operational

conditions that contribute to the improved methane production in terms of

methane yield and productivity without affecting the organic removal efficiency

such as accelerated start-up process, effect of higher sludge recycling rate, effect

of mixing and effect of co-digestion.

In chapter 4, the accelerated start-up process of the closed digester tank (CDT)

was achieved by transfer the seed sludge from either top or bottom of the open

digester tank (ODT). The bottom seed sludge transfer process led to better results

including a 24 day start-up period, stable pH condition (pH 6.8-7.2), high COD

removal efficiency (>90%), satisfactory VFA to Alk ratio (<0.3) and satisfactory

biogas production of nearly 1.8 kg m-3 d-1 with methane composition of 50 to 60%.

The presence of high amount of methanogens in the seed sludge was able to

reduce the long acclimatization period and the CDT could be fed with POME

within less than a day after the transfer process was completed. Scanning electron

microscopy (SEM) and fluorescence in situ hybridization (FISH) pictures revealed

abundant amounts of bacteria and methanogens, in particular Methanosaeta sp. in

the seed sludge samples which are very important for the biomethanation process.

In chapter 5, the effect of higher sludge recycling rate was studied by applying

organic loading rates (OLR) (between 1.0 and 10.0 kgCOD m-3 d-1) at different

sludge recycling rates (6 m3 d-1, 12 m3 d-1 and 18 m3 d-1). At sludge recycling rate

of 18 m3 d-1, the maximum OLR achieved was 10.0 kgCOD m-3 d-1 with biogas

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and methane productivity of 1.5 m3 m-3 d-1 and 0.9 m3 m-3 d-1, respectively. By

increasing the sludge recycling rate, the VFA concentration accumulated inside

the CDT was controlled below its inhibitory limit (1000 mg L-1) and the COD

removal efficiency recorded was above 95%. Two methanogens species

(Methanosarcina sp. and Methanosaeta concilii) have been identified from sludge

samples obtained from the digester and recycled stream. By increasing the sludge

recycling rate upon treatment at higher OLR, the treatment process was kept

stable with high COD removal efficiency.

In chapter 6, the effect of mixing was studied by applying four different mixing

regimes i.e natural mixing (NM), minimal horizontal mixing (MHM), minimal

horizontal and vertical mixing (MHVM) and vigorous mixing (VM) in the CDT.

The COD removal efficiency recorded satisfactory result (> 90%) when subjected

to the first three mixing regimes but reduced to the lowest of 85% when VM was

applied. In the NM, MHM and MHVM experiments, the maximum VFA

concentration in the CDT were recorded below the critical level of 1000 mg L-1.

The MHM gave the highest methane productivity at 1.4 m3 m-3 d-1 in comparison

to NM at 1.0 m3 m-3 d-1 and MHVM at 1.1 m3 m-3 d-1. This indicates MHM was

sufficient for contact between substrate and microorganisms and to release the

entrapped biogas inside the CDT. In contrast, VM was found to inhibit the

methane production process VFA concentration was recorded high at 3700 mg L-1.

The high VFA concentration have disrupted the syntrophic relationship between

acidogens and methanogens and inhibited the methanogenesis.

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In chapter 7, the effect of co-digestion of POME and RGWW under mesophilic

condition at different RGWW percentages (1.0-5.25%). The digester performance

in terms of COD removal efficiency and methane production rate and stability

were evaluated. At 1.0% of RGWW co-digested, both COD removal efficiency

and methane production rate showed satisfactory results with higher than 90% and

505 m3 d-1, respectively. However, once the percentage was increased to a

maximum of 5.25%, COD removal efficiency remains high but the methane

production rate reduced to 307 m3 d-1. At this stage, the digester became unstable

due to high VFA concentration of 913 mg L-1 and low cells concentration of 8.58

g L-1 inside the digester. This was due to the effect of plasmolysis on the

methanogens at high NaCl concentration. Thus co-digesting of RGWW with high

NaCl content and POME is satisfactory for COD removal but not for increasing

the methane production.

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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk ijazah Doktor Falsafah

PENINGKATAN BIOMETANASI EFLUEN KILANG SAWIT SEMASA RAWATAN ANAROBIK DI DALAM TANGKI PENCERNA TERTUTUP

Oleh

ALAWI BIN HJ SULAIMAN

April 2010

Pengerusi : Professor Mohd. Ali Hassan, PhD

Fakulti : Kejuruteraan

Projek memerangkap metana daripada rawatan anaerobik effluen kilang sawit

bagi mekanisma pembangunan bersih (CDM) semakin penting di dalam industri

sawit disebabkan oleh masalah penggunaan bahan bakar fosil seperti pemanasan

global, pencemaran air dan udara, pengurangan sumber, harga tenaga yang mahal

hujan asid dan lain-lain. Kaedah tradisional merawat effluen kilang sawit

menggunakan kolam terbuka atau tangki adalah amalan yang tidak lestari kerana

membebaskan sejumlah besar metana ke persekitaran dan seterusnya

menyumbang kepada gas rumah hijau. Dengan menggunakan tangki pencerna

anarobik tertutup, metana boleh diperangkap dan digunakan untuk menjana

elektrik samada untuk penggunaan kilang atau disambungkan ke grid Tenaga

Nasional Berhad. Tambahan pula dengan pendaftaran CDM dengan Persidangan

Rangkakerja Bangsa-Bangsa Bersatu ke atas Perubahan Cuaca (UNFCCC),

metana yang diperangkap boleh ditukar menjadi karbon kredit yang boleh

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didagangkan di pasaran antarabangsa sebagai pengurangan pembebasan yang

diperakui (CER). Ini mewujudkan keperluan yang segera bagi pihak industri

meningkatkan pemerangkapan metana untuk meningkatkan CER dan juga

penjanaan kuasa elektrik bagi membiayai sebahagian daripada kos projek. Bagi

tujuan ini, adalah penting untuk memahami pelbagai kondisi operasi yang

menyumbang kepada peningkatan pengeluaran metana di dalam bentuk hasilan

metana dan produktiviti tanpa memberi kesan kepada kecekapan penyingkiran

organic seperti proses permulaan pantas, kesan kadar kitar-semula enapcemar

yang tinggi, kesan pencampuran, dan kesan pencernaan bersama.

Di dalam bab 4, proses permulaan pantas telah berjaya dicapai dengan

pembenihan langsung dengan memindahkan enapcemar samada daripada

bahagian atas ataupun bawah tangki pencerna terbuka. Pemindahan benih

enapcemar bahagian bawah menghasilkan keputusan lebih baik termasuk tempoh

permulaan singkat 24 hari, keadaan pH stabil (pH 6.8-7.2), kecekapan

penyingkiran keperluan oksigen kimia yang tinggi (>90%), nisbah asid lelemak

meruap dan kealkalian yang memuaskan (<0.3), pengeluaran gas-bio yang

memuaskan hampir kepada 1.8 kg m-3 h-1 dan komposisi metana 50 ke 60%.

Kehadiran jumlah metanogen yang banyak di dalam benih enapcemar telah

berjaya memendekkan tempoh ubah-suai aklimitasi dan pencerna boleh disuap

dalam masa kurang sehari selepas selesai proses pemindahan benih enapcemar.

Mikroskopi pengimbas elektron dan hibridisasi kalimantan setempat (FISH)

menunjukkan jumlah bakteria dan metanogen yang banyak terutamanya

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Methanosaeta sp., di dalam sampel benih enapcemar yang amat penting untuk

proses biometanasi.

Di dalam bab 5, kesan kadar kitar-semula enapcemar yang tinggi telah dikaji

dengan menggunakan kadar bebanan organik (OLR) (di antara 1.0 and 10.0

kgCOD m-3 j-1) pada kadar kitar-semula yang berbeza (6 m3 j-1, 12 m3 j-1 and 18 m3

j-1). Pada kadar kitar-semula 18 m3 j-1, maksimum OLR yang dicapai adalah 10.0

kgCOD m-3 j-1, dengan produktiviti gas-bio dan metana adalah 1.5 m3 m-3 j-1 and

0.9 m3 m-3 j-1, masing-masing. Dengan meningkatkan kadar kitar-semula,

kepekatan VFA terkumpul di dalam CDT berjaya dikawal di bawah paras terencat

(1000 mg L-1) dan kecekapan penyingkiran COD direkodkan melebihi 95%. Dua

spesis metanogen (Methanosarcina sp. dan Methanosaeta concilii), telah

dikenalpasti daripada sampel enapcemar diperolehi di dalam pencerna dan aliran

kitar-semula. Dengan meningkatkan kadar kitar-semula pada tahap OLR yang

tinggi, proses rawatan dapat disetabilkan dengan kecekapan penyingkiran COD

yang tinggi.

Di dalam bab 6, kesan pencampuran telah dikaji pada 4 rejim pencampuran yang

berbeza; pencampuran semulajadi (NM), pencampuran minima melintang (MHM),

pencampuran minima melintang dan menegak (MHVM) dan pencampuran kuat

(VM). Kecekapan penyingkiran COD merekodkan keputusan memuaskan lebih

tinggi daripada 90% pada rejim pencampuran tiga yang pertama tetapi menurun

ke paras terendah 85% apabila VM digunakan. Di dalam ujikaji NM, MHM and

MHVM, kepekatan VFA direkodkan di bawah paras kritikal 1000 mg L-1. MHM

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memberikan produktiviti tertinggi pada 1.4 m3 m-3 j-1 dibandingkan dengan NM

pada 1.0 m3 m-3 j-1 dan MHVM at 1.1 m3 m-3 j-1. Ini menunjukkan MHM sudah

memadai untuk menghubungkan makanan dan mikroorganisma dan

membebaskan gas-bio yang terperangkap di dalam CDT. Sebaliknya di dalam

ujikaji VM didapati pengeluaran metana terencat di mana tiada metana dihasilkan

dan kepekatan asid lelemak meruap yang tinggi direkodkan pada 3700 mg L-1.

Tahap VFA yang tinggi telah menggangu hubungan sintropik di antara asidogen

dan metanogen dan seterusnya merencatkan metanogenesis.

Di dalam bab 7, kesan pencernaan bersama POME dan RGWW telah dikaji.

dalam keadaan mesofilik dan peratusan RGWW yang berbeza (1.0-5.25%).

Pencapaian pencerna dalam bentuk kecekapan penyingkiran COD dan kadar

pengeluaran metana dan kestabilan pencerna telah dinilai. Pada 1.0% RGWW

dicerna bersama, kecekapan penyingkiran COD dan pengeluaran metana

menunjukkan keputusan memuaskan dengan nilai lebih tinggi daripada 90% dan

505 m3 j-1, masing-masing. Walaubagaimanapun, apabila peratusan dinaikkan ke

paras maksima 5.25%, kecekapan penyingkiran COD kekal tinggi tetapi kadar

pengeluaran metana turun mengejut pada 307 m3 j-1. Pada peringkat ini, pencerna

telah menjadi tidak stabil dengan VFA yang tinggi sebanyak 913 mg L-1 dan

kepekatan sel yang rendah sebanyak 8.58 g L-1. Ini telah disebabkan oleh kesan

plasmalisis ke atas metanogen pada kepekatan natrium klorida yang tinggi. Oleh

itu pencernaan bersama RGWW berkepekatan NaCL tinggi dengan POME hanya

memuaskan kadar penyingkiran COD dan tetapi bukannya meningkatkan

pengeluaran metana.

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ACKNOWLEDGEMENTS

Praise to Allah, who has given me strength and consistency to complete this PhD

research. For all the help, guidance and assistance given, I would like to thank

many people. Firstly, I would like to thank the supervisory committee members

led by Professor Dr. Mohd Ali Hassan (chairman) and accompanied by Professor

Dr. Yoshihito Shirai (member from Kyushu Institute of Technology) and

Professor Dr. Ir. Azni Idris (member from Universiti Putra Malaysia) for their

support, valuable comments, assistance and guidance throughout this study.

Secondly I would like to appreciate the following individuals in Universiti Putra

Malaysia and FELDA Palm Industries Sdn. Bhd. for their invaluable contributions

in many ways; Dr. Suraini Abd-Aziz, Dr. Umi Kalsom Md. Shah, Dr. Nor’Aini

Abd Rahman, Dr. Farinazleen Mohd Ghazali, Dr. Phang Lai Yee, Dr. Shahrakbah

Yacob, Dr. Meisam Tabatabaei, Dr. Chong Mei Ling, Mrs. Norjan Yusoff, Mr.

Mohd Rafein Zakaria, Mr. Zulkhairi Mohd Yusoff, Mr. Zainuri Busu, Mr. Omar

Atan, Mr. Zainal Abidin Mohd Noh, Mr. Mohd Redho Mohamed and many more.

Thirdly I also would like to appreciate assistance provided by my fellow

colleagues in the Environmental Biotechnology Research Group UPM, especially

to biogas and biocompost group and undergraduate researchers who have assisted

in analysis and technical understanding. I also would like to appreciate my

beloved wife, Eliza Ishak and daughters, Sarah Nur Saffiya and Nur Iman Amani

for supporting and encouraging me to complete this study. Lastly but not least, I

would like to thank Universiti Teknologi MARA, Shah Alam and the government

of Malaysia for providing PhD scholarship for this study. Thank you all.

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I certify that a Thesis Examination Committee has met on 1 April 2010 to conduct the final examination of Alawi Bin Hj. Sulaiman on his thesis entitled “Enhanced Biomethanation of Palm Oil Mill Effluent During Anaerobic Treatment in a Closed Digester Tank” in accordance with the Universities and University Colledges Act 1971 and the Constitution of the Universiti Putra Malaysia [P.U.(A) 106] 15 March 1998. The committee recommends that the student be awarded the Doctor of Philosophy. Members of the Thesis Examination Committee were as follows: Luqman Chuah Abdullah, PhD Associate Professor Faculty of Engineering Universiti Putra Malaysia (Chairman) Ling Tau Chuan, PhD Associate Professor Faculty of Engineering Universiti Putra Malaysia (Internal Examiner) Salmiaton Ali, PhD Associate Professor Faculty Universiti Putra Malaysia (Internal Examiner) Abdul Latif Ahmad, PhD Professor School of Chemical Engineering Universiti Sains Malaysia Malaysia (External Examiner)

SAMSUDDIN SULAIMAN, PhD Professor and Deputy Dean School of Graduate Studies Universiti Putra Malaysia Date: 30 September 2010

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This thesis was submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfilment of the requirement for the degree of Doctor of Philosophy. The members of the Supervisory Committee were as follows: Mohd Ali Hassan, PhD Professor and Dean Faculty of Biotechnology and Biomolecular Sciences / Faculty of Engineering Universiti Putra Malaysia (Chairman) Yoshihito Shirai, PhD Professor Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology Japan (Member) Azni Idris, PhD Professor Faculty of Engineering Universiti Putra Malaysia (Member)

_______________________________ HASANAH MOHD GHAZALI, PhD Professor and Dean School of Graduate Studies Universiti Putra Malaysia Date: 21 October 2010

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DECLARATION I declare that the thesis is my original work except for quotations and citations which have been duly acknowledged. I also declare that it has not been previously, and is not concurrently, submitted for any other degree at Universiti Putra Malaysia or any other institution.

__________________________ ALAWI BIN HJ SULAIMAN Date: 1 April 2010

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TABLE OF CONTENTS

Page ABSTRACT ii-v ABSTRAK vi-ix ACKNOWLEDGEMENTS x APPROVAL xi-xii DECLARATION xiii LIST OF TABLES xviii-xix LIST OF FIGURES xx-xxii LIST OF ABBREVIATION xxiii-xxv CHAPTER 1. INTRODUCTION

1.1 Threats of Climate Change 1 1.2 Palm oil Industry and Methane Emissions 2 1.3 Methane Emission Reduction and International 3-4

Collaboration between UPM-FELDA-KIT 1.4 Rationale of This Study 4-6 1.5 Research Objectives 6 1.6 Research Hypothesis 7

2. LITERATURE REVIEW

2.1 Introduction to CDM and POME Treatment 8-11 2.2 Technologies for POME treatment 11-19 2.3 The Needs for Accelerated Start-up for 19-22

Biomethanation of Palm Oil Mill Effluent 2.4 The Effect of Higher Sludge Recycling 22-27

Rate on Anaerobic Treatment and Biomethanation of Palm Oil Mill Effluent

2.5 The Effect of Mixing on Anaerobic Treatment and 27-28 Biomethanation of Palm Oil Mill Effluent

2.6 The Effect Co-digestion of Palm Oil Mill Effluent 28-32 and Refined Glycerine Wash Water on Anaerobic Treatment and Biomethanation of Palm Oil Mill Effluent

2.3 Palm Oil Industry, Its Sustainability and CDM Project 32-36 2.4 The Overview of the Registered CDM Methane 37-42

Capture Project in Malaysia 2.5 The Experience with CDM project in Serting Hilir 42-45

Palm Oil Mill, Malaysia 2.6 Future Outlook 46-49

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3. GENERAL MATERIALS AND METHODS 3.1 Materials:

3.1.1 Chemicals Reagents and Suppliers 50-52 3.1.2 Palm Oil Mill Effluent (POME) 52 3.1.3 POME Seed Sludge Source 53-54 3.1.4 The 500 m3 Digester Set-up and Operation 54-55 3.1.5 Measuring Equipment 56-59

3.2 Methods: 3.2.1 Analytical Methods 59-68 3.2.2 General Equations 68-73

4. ACCELERATED START-UP OF A SEMI-COMMERCIAL DIGESTER TANK TREATING PALM OIL MILL EFFLUENT WITH SLUDGE SEEDING FOR METHANE PRODUCTION 4.1 Introduction 74-79 4.2 Materials and Methods

4.2.1 Semi-commercial Digester Set-up 79-80 4.2.2 Source of Seed Sludge and POME 80-81 4.2.3 Experimental Set-up 81-82 4.2.4 Chemical and Microbial Analyses 82-83

4.3 Results and Discussion 4.3.1 Sludge Transfer Process 83-89 and Acclimatization Period 4.3.2 Start-up Strategy 90-93 4.3.3 Stability of the Digester 93-95 4.3.4 Methane Production 95-98

4.4 Conclusions 98-99

5. THE EFFECT OF HIGHER SLUDGE RECYCLING RATE ON ANAEROBIC TREATMENT AND BIOMETHANATION OF PALM OIL MILL EFFLUENT 5.1 Introduction 100-101 5.2 Materials and Methods 101-103 5.3 Results and Discussion

5.3.1 POME Feeding Profiles, Digester Stability 104-105 and Performances 5.3.2 COD Removal Efficiency 105-106 5.3.3 Volatile Fatty Acid (VFA) Accumulation 106-109 5.3.4 Productivity of Biogas and Methane and 109-111 Methane yield 5.3.5 Fluorescent in situ Hybridization (FISH) 111-112

5.4 Conclusions 113

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6. THE EFFECT OF MIXING ON ANAEROBIC TREATMENT AND BIOMETHANATION OF PALM OIL MILL EFFLUENT 6.1 Introduction 114-116 6.2 Materials and Methods

6.2.1 Experimental Set-up 116-118 6.2.2 The Feeding Profiles 118-119 6.2.3 Chemical Analyses 119-120 6.2.4 Fluorescent in situ Hybridization (FISH) 120 Technique

6.3 Results and Discussion 6.3.1 The Performance of the Closed Digester 121-125 6.3.2 The Stability of the Closed Digester 125-128

6.4 Conclusions 128

7. THE EFFECT OF CO-DIGESTION OF PALM OIL MILL EFFLUENT AND REFINED GLYCERINE WASH WATER ON ANAEROBIC TREATMENT AND BIOMETHANATION 7.1 Introduction 129-133 7.2 Materials and Methods 7.2.1 The System Set-up and Operation 133-134 7.2.2 Chemical Analyses 134-135 7.2.3 The Feeding Profiles 135-136 7.3 Results and Discussion 7.3.1 The performance of the Digester 136-142 7.3.2 The System Stability 142-145 7.5 Conclusions 145

8. SUMMARY, CONCLUSION AND RECOMMENDATIONS FOR FUTURE STUDIES 8.1. Summary 146-148 8.2. General Conclusion 149-150 8.3. Recommendation for Future Studies 150-153

REFERENCES 154-168 LIST OF PUBLICATIONS AND CONFERENCES 169-172

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APPENDICES Appendix 1 - Sample calculation. 173-175 Appendix 2 - Copy of Published Journal Paper and 176-189 Acceptance Letter for Article in Chapter 2. Appendix 3 - Copy of Published Journal Paper and 190-205 Acceptance Letter for Article in Chapter 4. Appendix 4 - Copy of Published Journal Paper and 206-213 Acceptance Letter for Article in Chapter 5. Appendix 5 - Copy of Published Journal Paper and 214-222 Acceptance Letter for Article in Chapter 6. Appendix 6 - Copy of Published Journal Paper and 223-232 Acceptance Letter for Article in Chapter 7. BIODATA OF STUDENT 233