Hassan, Siti Roshayu (2016) Anaerobic Digestion Of Recycled Paper Mill Effluent (Rpme) Using Modified Anaerobic Hybrid Baffled (Mahb) Reactor. PhD thesis, Universiti Sains Malaysia.
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Abstract
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. ________________________________________________________________________________________________________________________ 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 xxviii 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.
| Item Type: | Thesis (PhD) |
|---|---|
| Additional Information: | Full text is available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=2786 |
| Subjects: | T Technology T Technology > TA Engineering (General). Civil engineering (General) > TA1-2040 Engineering (General). Civil engineering (General) |
| Divisions: | Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Awam (School of Civil Engineering) > Thesis |
| Depositing User: | Mr Mohd Jasnizam Mohd Salleh |
| Date Deposited: | 12 Jul 2018 06:58 |
| Last Modified: | 14 Aug 2018 08:18 |
| URI: | http://eprints.usm.my/id/eprint/41005 |
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