Anaerobic Digestion Of Recycled Paper Mill Effluent (Rpme) Using Modified Anaerobic Hybrid Baffled (Mahb) Reactor
Reaktor bersesekat hibrid anaerob terubah suai (MAHB) adalah reaktor yang sering digunakan untuk biopenukaran bahan organik di dalam industri rawatan sisa kumbahan disamping menghasilkan metana gas dengan bantuan mikroorganisma anaerobik. Dalam projek ini, reaktor MAHB berisipadu 58 L telah berja...
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| Format: | Thesis |
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2016
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| Online Access: | http://eprints.usm.my/41005/ http://eprints.usm.my/41005/1/Anaerobic_Digestion_Of_Recycled_Paper_Mill_Effluent_(Rpme)_Using_Modified_Anaerobic_Hybrid_Baffled_(Mahb)_Reactor.pdf |
| Summary: | Reaktor bersesekat hibrid anaerob terubah suai (MAHB) adalah reaktor yang
sering digunakan untuk biopenukaran bahan organik di dalam industri rawatan sisa
kumbahan disamping menghasilkan metana gas dengan bantuan mikroorganisma
anaerobik. Dalam projek ini, reaktor MAHB berisipadu 58 L telah berjaya direka dan
dikendalikan untuk merawat efluen kilang kertas kitar semula (RPME). Proses
permulaan (start up) berjaya dicapai dalam tempoh 28 hari, dengan menghasilkan
65.97% biogas (0.31 L) dan menyingkirkan keperluan oksigen kimia (COD) yang
tinggi (86.41%) serta menunjukkan nilai pH yang stabil (7.2 – 7.4). Selain itu,
prestasi reaktor MAHB juga dikaji untuk proses berterusan, prestasi reaktor petak
kecil “compartment”, kadar kemasukan organik (OLR) dan nilai bekalan kepekatan
COD berbeza. Keputusan menunjukkan bahawa reaktor MAHB berjaya beroperasi
pada proses yang berterusan dan setiap petak kecil bertindak sebagai reaktor individu
yang menyumbang kepada kadar pengeluaran metana yang tinggi. Tambahan pula,
pemasangan sesekat secara berdiri dan tergantung ke dalam reactor MAHB
menyediakan pencampuran sempurna antara biomas dan substrat. Sesekat yang
mempunyai saiz dan bentuk yang berbeza juga menyumbang kepada pertumbuhan
mikroorganisma yang berbeza dalam setiap petak yang berbeza yang membantu
pemisahan fasa. Sesekat bertangga darjah 35° dengan tangga mendatar di petak 1
menunjukkan bentuk sesekat yang menyumbang kepada prestasi yang lebih tinggi.
Kesan OLR dan kepekatan bekalan COD menunjukkan bahawa MAHB reaktor
memberikan prestasi tinggi dari segi kadar pengeluaran metana dan kecekapan
penyingkiran COD apabila OLR dan kepekatan COD meningkat sehingga ia
mencapai keadaan optimum. Interaksi dan pengoptimuman penghadaman RPME
telah dilakukan menggunakan kaedah permukaan sambutan (RSM) dengan dua
pembolehubah (masa penahanan hidraulik (HRT) dan kepekatan bekalan COD) dan
tiga respon (kepekatan COD, kepekatan lignin dan kadar penghasilan metana gas).
Keputusan ujikaji ini menunjukkan optimum penyingkiran COD sebanyak 97.42 %
dan lignin pada 59.59 % serta penghasilan gas metana sebanyak 8.07 L CH4 hari-1
adalah pada HRT 3.93 hari dan bekalan kepekatan COD sebanyak 3020.88 mg L-1.
Penemuan ini adalah hampir sama dengan ramalan optimum oleh pemasangan
analisis menggunakan rangkaian neural tiruan (ANN) untuk penyingkiran COD
(98.16%), penyingkiran lignin (77.29%) dan pengeluran metana gas (8.34 L hari-1).
Kajian kinetik pada fasa pencernaan anaerobik yang berbeza mendedahkan bahawa
hidrolisis adalah proses kadar mengehadkan “rate limiting step”. Model kinetic
Monod dan Contois menunjukkan bahawa kedua-dua memberi ramalan yangmemuaskan dengan kadar maksimum pertumbuhan spesifik mikrob (µ.max) masingmasing
adalah 1.476 dan 0.6796 L. Selain kinetik, tingkah laku hidrodinamik
menunjukkan bahawa ruang mati “dead space” dalam MAHB reaktor adalah antara
10.13-10.39% untuk air paip dan 1.45 - 5% untuk RPME. Corak pergerakan
hidraulik dalam reaktor MAHB menunjukkan perantara antara aliran pasang dan
pengantara yang lebih dekat dengan palam aliran berbanding aliran perantaraan
dengan kecekapan hidraulik antara 0.20-0.64 untuk air paip dan 1.00-3.95 untuk
RPME.
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Modified anaerobic hybrid baffled (MAHB) reactor is a recent reactor that
widely used for rapid bioconversion of organic matter in industrial wastewater
treatment process to produce methane with the help of anaerobic microorganism. A
pilot scale MAHB reactor (58 L) was successfully fabricated and operated for
treatment of recycled paper mill effluent (RPME). A successful start up process were
achieved less than a month (28 days) with a high COD removal efficiency of
86.41 % and pH values between 7.2 – 7.4 at steady state condition. The methane
content at the end of start up was recorded at 65.97 % with a total biogas volume of
0.31 L. During the process study, the MAHB reactor were run to study the
performance of MAHB reactor during continuous feeding, compartment-wise
profile, different organic loading rates (OLRs) and also different feeding
concentrations. Result shows that the MAHB reactor successfully operated at
continuous process and each compartments act as an individual reactor which gives
high methane production rate. Furthermore, installation of standing and hanging
baffles and introduction of packing materials into MAHB reactor provides perfect
mixing between biomass and substrates. The different size and shaped of baffles also
contributes to different growth of microorganism in each different compartments that
leds to phase separations. The 35° ladder with inclining horizontal ladder baffled in
Compartment 1 shows the best shaped of baffle that contributes to higher
performances of MAHB. The effect of OLR and feeding COD concentrations shows
that MAHB reactor gives high performance in terms of methane production rates and
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COD removal efficiencies as the OLR and feeding COD concentration increases
until it reach its optimum condition. Interaction and optimization of RPME digestion
were conducted using D-optimal design of response surface methodology (RSM)
with two variables i.e. hydraulic retention time (HRT) and feeding COD
concentrations. The optimum conditions that yield a highest COD and lignin
removal efficiency as well as methane production rate was HRT of 3.93 days,
feeding COD concentration of 3020.88 mg L-1 that gaves a COD removal efficiency
of 97.42 %, lignin removal efficiency of 59.59 % and methane production rate of
8.07 L CH4 day-1 with desirability value of 0.897. This finding were in close
agreement with the predicted optimum COD removal efficiecncy, lignin removal
efficiency and methane production rate predicted by fitting analysis using artificial
neural network (ANN). The optimum predicted output obained by ANN are
98.16 %, 77.29 % and 8.34 L day-1 for COD removal, lignin removal and methane
production rate, respectively. Different phases of anaerobic digestion were undergo
kinetic studies which revealed that hydrolysis is the rate limiting step. Applied
Monod and Contois kinetic models, it shows that both give satisfactory prediction
with (µ.max) values of 1.476 and 0.6796 L day-1, respectively. Instead of kinetics, the
hydrodynamic behaviours shows that dead space in MAHB reactor is between
10.13 – 10.39 % for tap water and 1.45 – 5 % for RPME. The flow pattern within the
MAHB reactors showed an intermediary between the plug flows and intermediate
which closer to plug flow compared to intermediate flow with a hydraulic efficiency
between 0.20 – 0.64 for tap water and 1.00 – 3.95 for RPME.
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