Enhancing biogas production of Tofu wastewater by co-digestion

Tofu WWTP in Subdistrict Srandakan, Bantul, Indonesia has low performance indicated by low removal efficiency of COD and TSS (<30 ), and pH effluent tends to be acidic (<6.5). On the other hand wastewater from "lethek"noodle and wingko industries (regional specialties) has not been treated. The remaining ash from tofu production is not utilized. The study aimed to observe the wastewater mixture composition on biogas volume. The digester tank was made of a 5 L water container with a working volume of 4 L. Semi-continuous feeding every 2 d and HRT 30 d. The mixture composition of tofu (T), noodle (M) and wingko (W) wastewater was P1=1:0:0; P2=0:1:0; P3=0:0:1; P4=1:1:1: P5=7:3:1; P6=3:1:7 and P7=1:7:3. The remaining ash from tofu production was added to obtain pH of 7±0.5. Temperature, pH, TDS, and biogas volume measurements were taken periodically. At the beginning of the experiment, the C/N ratio was tested, while COD and TSS were tested at the beginning and day 30 of the experiment. The result showed the initial C/N ratio in the range of 63-224. pH effluent increased and after 2nd week was relatively stable in the range of 7.2, while TDS effluent was in the range of 1600-3500 ppm. The biogas production rate in the range of 32.9 ml/g COD added to 199.8 ml/g COD added. © 2024 Author(s).