Natural Flocculant from Durio zibethinus Seed Starch for Municipal Solid Waste Landfill Leachate Treatment

• Main Author: Ahmad Zamri, Mohd Faiz Muaz
• Format: Thesis
• Language: English
• Published: 2016
• Subjects: T Technology; TA1-2040 Engineering (General). Civil engineering (General)
• Online Access: http://eprints.usm.my/40717/1/Natural_Flocculant_from_Durio_zibethinus_Seed_Starch_for_Municipal_Solid_Waste_Landfill_Leachate_Treatment.pdf; http://eprints.usm.my/40717/

Penggunaan penggumpal polialuminium klorida (PAC) sangat menonjol di dalam olahan larut lesap kambus tanah. Aplikasi PAC di dalam proses penggumpalan telah terbukti di antara penggumpal yang efektif untuk olahan larut lesap kambus tanah. Walaubagaimanapun, PAC dikenal pasti berpotensi menghasilkan lebihan toksik aluminium kepada persekitaran akuatik. Sebagai alternatif, kombinasi bersama penggumpal tambahan semulajadi boleh mengurangkan dos dan pergantungan kepada PAC. Di dalam kajian ini, penggumpal tambahan berasaskan bahan semulajadi daripada kanji biji durian (Durio zibithenus) telah digunakan untuk olahan larut lesap kambus tanah. Sampel larut lesap kambus tanah tapak telah diambil dari tapak pelupusan Matang yang terletak di Taiping, Perak. Kanji biji durian telah diekstrak menggunakan kaedah pengekstrakan kering dan kaedah pengekstrakan basah. Kanji terbaik yang diperolehi, diubahsuai dengan kaedah persilangan cantuman pengumpal kanji untuk memperbaiki proses rawatan. Keadaan eksperimen dalam penyikiran warna, keperluan oksigen kimia (COD), pepejal terampai dan kekeruhan telah dioptimumkan lagi menggunakan kaedah statistik tindak balas pemukaan (RSM). Di samping itu juga nilai kelajuan pemendakan (SV) dibandingkan dan digunakan untuk reka bentuk pengiraan tangka campuran dan tangki pemendakan. Berdasarkan pada hasil eksperimen, pengunaan penggumpal tambahan dari kanji pengekstrakan basah (WM-DSS) telah meninggikan peratus penyingkiran bagi warna, pepejal terampai dan kekeruhan masing-masing melebihi sebanyak 0.4 %, 2.9 % dan 13.2 % berbanding PAC sahaja (88.8%, 65.9 %, 90.7 % dan 80.5 %). Malahan indeks kelajuan pemendakan juga bertambah baik dari 531.3 mL/g kepada 158.1 mL/g. Sebaliknya, pengunaan penggumpal tambahan daripada kanji pengekstarakan kering (DM-DSS) telah menurun dan mengurangkan peratus penyingkiran bagi warna, pepejal terampai dan kekeruhan masing-masing melebihi sebanyak 25 %, 1.6 % dan 2.8 % berbanding PAC sahaja (90.2 %, 59.6 % 97.2 % dan 95.0 %). Dalam hal ini, ia jelas menunjukan aplikasi pengekstrakan secara lembab boleh diyakini untuk digunakan sebagai kaedah pembangunan pengumpal tambahan berasaskan kanji. Pada masa yang sama, modifikasi persilangan cantuman pengumpal kanji (CWM-DSS) telah meninggikan peratus penyingkiran bagi warna, COD, pepejal terampai dan kekeruhan masingmasing melebihi sebanyak 1.7 %, 5.1 %, 14.8 %, and 14 % berbanding PAC sahaja (94.4 %, 55.8 %, 70.4 % dan 81.1 %). Tambahan pula, modifikasi persilangan cantuman kanji ini telah mampu mengurangkan 0.557 g/L dos PAC. Malahan, pengunaan CWM-DSS ia telah berjaya mengurangkan bilangan tangki pemendakan dari 6 kepada 3-unit tangki dan meningkatkan isipadu aturan olahan larut lesap kambus tanah yang telah dirawat dari 2376 m3/hari kepada 2404.08 m3/hari. Oleh yang demikian, ini sangat jelas dapat diperhatikan bahawa pengunaan pengumpal CWM-DSS dapat digunakan di dalam proses rawatan olahan larut lesap kambus tanah. ________________________________________________________________________________________________________________________ The used of poly aluminum chloride (PAC) coagulant is prominent in landfill leachate treatment. PAC coagulant is proven to be among the effective coagulants for landfill leachate treatment. However, it was found that PAC coagulant has a toxic potential of aluminum residual to the aquatic environment. As an alternative, the combination of natural flocculants with inorganic coagulants could reduce the dosage and dependence on the PAC coagulant and improved the flocculant properties. In this study, natural based flocculants from durian seed starch were used for landfill leachate treatment. The landfill leachate samples were collected from Matang landfill located at Taiping, Perak. The durian seed starches were extracted using dry milling and wet milling extraction method. The best starch obtained was further modified by crosslinking modification method to improve the treatment process. The experimental condition in removing color, Chemical Oxygen Demand (COD), suspended solid and turbidity were further optimized statistically using Response Surface Method (RSM). The settling velocity values were compared and used for mixing and settling tanks calculation design. According to the results, the use of wet milling durian seed starch (WM-DSS) as a flocculant increased the removal percentage of color, suspended solids and turbidity by 0.4 %, 2.9 %, and 13.2 % compared to PAC coagulants alone (88.8%, 90.7 % and 80.5 %). Besides, the sludge velocity index (SVI) was also improved from 531.3 mL/g to 158.1 mL/g. In contrast, the use of dry milling durian seed starch (DM-DSS) flocculants had decreased the removal percentage of chemical oxygen demand (COD), suspended solids and turbidity by 25 %, 1.6 %, and 2.8 % compared to PAC coagulants alone (59.6 % 97.2 % and 95.0 %). In this respect, wet milling extraction method was effective to be used for starch flocculants synthesis. In fact, the crosslinking modification of the wet milling starch flocculants (CWM-DSS) further increased the removal percentage of color, chemical oxygen demand (COD), suspended solids and turbidity by 1.7 %, 5.1 %, 14.8 %, and 14 % compared to PAC alone (94.4 %, 55.8 %, 70.4 % and 81.1 %). Moreover, this starch modification had able to reduce 0.557 g/L concentration of PAC coagulant for landfill leachate treatment. Besides, the used of CWM-DSS flocculants able to reduce the number of settling tank from 6 to 3 units and increased the volume of treated leachate from 2376 m3/day to 2404.08 m3/day. Therefore, it was clearly observed that the used of CWM-DSS flocculants is effective to be used for landfill leachate treatment process.