Characterization of Cassava Sludge and Tofu Wastewater as Anaerobic Digestion Substrates for Biogas Production

Daya Wulandari; Riztamala Diana; Laras Niti Mulyani; Julien  Alpa Harzon; Mella Aulia

doi:10.53893/ijrvocas.v6i2.528

Authors

Daya Wulandari Politeknik Manufaktur Negeri Bangka Belitung
Riztamala Diana Politeknik Manufaktur Negeri Bangka Belitung
Laras Niti Mulyani Politeknik Manufaktur Negeri Bangka Belitung
Julien Alpa Harzon Politeknik Manufaktur Negeri Bangka Belitung
Mella Aulia Politeknik Manufaktur Negeri Bangka Belitung

DOI:

https://doi.org/10.53893/ijrvocas.v6i2.528

Keywords:

Biogas, Anaerobic Digestion, Cassava Sludge, Tofu Wastewater, Physicochemical Characterization, Gas Production

Abstract

The increasing generation of organic waste from the food processing industry has created opportunities for converting biodegradable residues into renewable energy. Cassava sludge and tofu wastewater contain biodegradable organic matter and may serve as substrates for anaerobic digestion. This study aimed to characterize the initial physicochemical properties of cassava sludge and tofu wastewater and assess their characteristics and endpoint gas profiles under different substrate formulations. Four formulations were evaluated: cassava sludge (S1), cassava sludge mixed with tofu wastewater (S2), tofu wastewater (S3), and cassava sludge supplemented with a microbial inoculum (S4). Activated Effective Microorganisms 4 (EM4) was applied to all formulations. Initial characterization included pH, temperature, total nitrogen (TN), total suspended solids (TSS), turbidity, chemical oxygen demand (COD), and biochemical oxygen demand (BOD). Reactor pH and temperature were monitored every three days for 21 days batch digestion period, followed by endpoint gas composition analysis. Cassava sludge exhibited the highest initial COD and BOD concentrations, at 19,409 and 8,640 mg/L, respectively, with TSS and TN concentrations of 680 and 270 mg/L. The cassava sludge tofu wastewater formulation showed COD and BOD concentrations of (13,355 mg/L and 6,028 mg/L), respectively, whereas tofu wastewater showed values of (6,644 mg/L and 2,974 mg/L). S4 exhibited lower initial COD and BOD concentrations of 389 and 175 mg/L, respectively, reflecting the initial characteristics of the formulation containing additional microbial inoculum. During the digestion period, temperatures ranged from (25.1–32.2 °C). while pH generally increased across the formulations. At the end of the 21 days digestion period, S4 showed the highest CH₄ reading (65.4%LEL), followed by S1 (9.7%LEL), S3 (4.7%LEL), and S2 (3.9%LEL). The observed results indicate differences in endpoint gas characteristics among the substrate formulations under the experimental conditions. Overall, the initial physicochemical characteristics and endpoint gas profiles provide a basis for assessing cassava sludge and tofu wastewater as substrates for anaerobic digestion.

References

[1] D. Lisa and I. Restiaty, “Gema Lingkungan Kesehatan Utilization of Liquid Waste from Tofu Production Using Anaerobic Methods for Biogas,” vol. 22, no. 2, pp. 95–102, 2024.

[2] A. W. Agustin, P. Studi, P. Fisika, and U. Jember, “Potensi Pemanfaatan Biogas Dari Sampah Organik Sebagai Sumber Energi Terbarukan,” vol. 2, no. 6, pp. 1109–1116, 2023, doi: 10.55123/insologi.v2i6.2841.

[3] P. D. Purboyo, “Analysis of Anaerobic Digestion Installation Testing for Tofu Liquid Waste Utilization into Biogas with the Addition of Cow Manure Variations,” vol. 5, no. 1, pp. 1–12, 2024.

[4] N. I. N. F. Fauzi, A. S. S. Latif, and S. A. J. Müller, “A study on biogas production from cassava peel and stem in anaerobic digestion reactor,” Int. J. Environ. Sci. Technol., no. 0123456789, 2021, doi: 10.1007/s13762-021-03222-4.

[5] A. Adeputra, L. Kalsum, and A. Hasan, “CO 2 and H 2 S Absorption in Tofu Liquid Waste Biogas using Packed Bed Scrubber with Variation of MEA Concentration and Flow Rate,” vol. 3, no. 2, pp. 23–28, 2023.

[6] A. Zaeni and P. E. Susilowati, “Biogas production from cassava waste : effect of concentration,” 2020, doi: 10.1088/1757-899X/778/1/012115.

[7] I. R. Ardaniswari and W. P. Nugravianto, “Biogas Production from Tofu Waste to Improve the Environmental Performance of Tofu Industry,” Agroindustrial J., vol. 7, no. 1, pp. 459–464, 2020.

[8] J. A. Muzakki, “The Effect of Additional EM-4 Bioactivator on Biogas Production From Tofu Industrial Liquid Waste,” Cermin J., vol. 5, pp. 362–372, 2021.

[9] I. Syaichurrozi, E. Suhendi, I. Kustiningsih, and S. Nurulshani, “Bioresource Technology Reports Enhancement of biogas production through anaerobic co-digestion of tofu wastewater and cassava starch wastewater in Indonesia,” vol. 33, no. November 2024, 2026.

[10] M. Arriza, N. Tahta, B. B. Cezarridfalah, and E. A. Saputro, “Review : Biogas Fermentation Process,” vol. 4, no. 1, pp. 24–31, 2023.

[11] A. Hadiyarto, D. Soetrisnanto, F. M. Huda, and N. A. Iswara, “The Effect of C / N Ratio and Type of Microbes Sludge to Biogas Production : Combination of Tapioca Industrial Wastewater and Tofu Industrial Wastewater,” vol. 03036, pp. 2017–2019, 2018.

[12] I. Syaichurrozi, S. Nurulshani, and A. A. Pramudita, “Biogas generation from anaerobic co-digestion of tofu liquid waste and tapioca flour liquid waste at various initial pHs,” vol. 26, no. 7, pp. 11–23, 2025.

[13] I. Syaichurrozi et al., “Biogas generation from liquid waste of Beneng taro starch processing : The effect of initial pH,” vol. 27, no. 3, pp. 55–68, 2026.

[14] R. Ramadani, S. Samsunar, and M. Utami, “Analysis of Temperature , Power of Hydrogen ( pH ), Chemical Oxygen Demand ( COD ), and Biologycal Oxygen Demand ( BOD ) in Domestic Wastewater in Sukoharjo Environmental Office Analisis Suhu , Derajat Keasaman ( pH ), Chemical Oxygen Demand ( COD ), dan Biologycal Oxygen Demand ( BOD ) dalam Air Limbah Domestik di Dinas Lingkungan Hidup Sukoharjo,” vol. 6, no. 2, pp. 12–22, 2021.

[15] J. Ilmiah and T. Kimia, “Optimasi Fermentasi Anaerob pada Produksi Biogas dari Eceng Gondok dan Kotoran Sapi dengan Response Surface Methodology Optimization of Anaerobic Fermentation in Biogas Production from Water Hyacinth and Cow Dung with Response Surface Methodology,” vol. 9, no. 1, pp. 1–7, 2025, doi: 10.32493/jitk.v9i1.44185.

[16] D. Wibowo et al., “Pemanfaatan Limbah Cair Tahu Menjadi Biogas : Optimasi Laju Pertumbuhan Bakteri Dalam Produksi Gas HCHO dan TVOC,” vol. 9, pp. 1–10, 2025.

[17] B. Muanah, Suhairin, Istiqamah. Nur Annisa, “Analisis Kandungan Karbondiokasida dan Gas Metana Pada Pembuatan Biogas Berbahan Limbah Organik,” vol. 17, no. April, pp. 46–54, 2024.

[18] Y. W. and H. Hadiyanto, “Life cycle assessment of biodiesel production from crude palm oil : A case study of three Indonesian biodiesel plants Life cycle assessment of biodiesel production from crude palm oil : A case study of three Indonesian biodiesel plants,” pp. 4–11, 2019, doi: 10.1088/1755-1315/348/1/012002.