Trifandi Lasalewo, Iqbal Syaichurrozi
Tofu industry liquid waste (TILW) contains high organic content, so direct discharge into the environment is unacceptable. Thus, this waste is suitable to be processed to biogas via anaerobic digestion (AD). Biogas can be enhanced through trace element addition and the combination of AD with other methods. Therefore, this study aimed to evaluate the effect of NiCl2 .6H2 O supplementation and microbial electrolysis cell integration (AD-MEC) on biogas production from TILW. Batch experiments were conducted with NiCl2 .6H2 O concentrations of 0–8 mg/L. Then, the performance of AD and AD-MEC was compared. In the AD-MEC, the voltage was kept constant at 1.5 V. The results showed that AD-MEC with 2 mg/L NiCl2 .6H2 O achieved the highest cumulative biogas yield of 550.82 mL/L and cumulative methane yield of 396.48 mL-CH4 /L. Due to the presence of MEC in AD at the same NiCl2 .6H2 O dose (2 mg/L), total solid (TS) removal increased from 28.57% in AD to 37.50% in AD-MEC, while total suspended solid (TSS) and total dissolved solid (TDS) removals improved from 25.81% to 39.87% and from 31.14% to 34.93%, respectively. Despite requiring a small electrical input, AD-MEC generated a surplus energy of 3915.79 J, about 34% or 1.3 times higher than conventional AD. Therefore, AD-MEC with an addition of 2 mg/L NiCl2 .6H2 O provided the optimal condition for TILW treatment by enhancing methane production, energy recovery, and pollutant removal. © 2026, Polskie Towarzystwo Inzynierii Ekologicznej (PTIE). All rights reserved.
Department of Industrial Engineering, Universitas Negeri Gorontalo, Jl. Jend. Sudirman No.6, Gorontalo, Kota Gorontalo, 96128, Indonesia; Department of Chemical Engineering, Faculty of Engineering, Universitas Sultan Ageng Tirtayasa, Banten, Cilegon, Indonesia
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