A review: biogas production from tofu liquid waste

Abstract

The tofu consumption will increase in the future. As consequent, the tofu production increases significantly. In other side, the amount of tofu wastes also increases. The solid waste can be utilized as solid compost but the liquid waste is discharged directly to the waster bodies at the moment. The latter is potential to be used as biogas feedstock. Some important factors affecting biogas rate need to be considered such as power Hydrogen (pH), Chemical Oxygen Demand (COD) to Nitrogen ratio, Total solid (TS) content, biological agent addition, initial concentration and two-stage anaerobic digestion. Furthermore, purification of the biogas formed by digestion of the tofu liquid waste is needed to be conducted to increase the methane content and decrease carbon dioxide (CO2) and hydrogensulfide (H2S) content. The H2S has to be removed prior to CO2 removal. The H2S can be removed by biofiltration and CO2 can be removed by biological absorption with help of microalgae. The effluent of anaerobic digester (digestate) may still contain high pollutant so it can be used as nutrient sources for microalgae. The zero waste system for tofu industries is successfully proposed in this paper. Future trend in treating tofu liquid waste in not only for biogas production butalso for biohydrogen production.

Effect of Organic Waste Addition into Animal Manure on Biogas Production Using Anaerobic Digestion Method

“…In the future, to upgrade the results so that the biomethane can be applied efficiently. It can use biofiltration, membrane, or activated carbon to eliminate the H2S (Budiyono and Syaichurrozi, 2020). Also, it is necessary to analyze the pretreatment of raw material.…”

“…Therefore, various biogas production technique using tofu waste have been performed. For example, Budiyono and Syaichurrozi (2020) investigated biogas production from tofu waste using a two-phase anaerobic digestion method where biogas becomes the top product while the effluent becomes the bottom product. A renewable energy technology promises to reduce waste while producing renewable energy known as anaerobic digestion.…”

Effectiveness Analysis of Anaerobic Digestion Method in Making Biogas from Animal Manure and Tofu Liquid Waste

“…Then for the exponential phase, the bacteria stop to growth and the biogas production tend to be constant. The stationary phase is then followed by the death phase, which is marked by an increase in the mortality rate that exceeds the growth rate (Budiyono and Syaichurrozi, 2020).…”

“…One type of raw material used for biogas production is tofu liquid waste which comes from the by-product of the tofu industrial production process. Tofu liquid waste is hazardous if disposed of directly into the environment because it contains high COD and BOD values (Budiyono and Syaichurrozi, 2020). However, tofu liquid waste contains high organic and nutritional substances, making it suitable for processing into biogas using the anaerobic digestion method.…”

“…Finally, all of these products are converted into CH2, CO2, and water at the last stage, where there is methanogenic bacterial activity (Kwietniewska and Tys, 2014). (Budiyono and Syaichurrozi, 2020) In previous studies that used the anaerobic digestion method, many used various kinds of raw materials, such as research conducted by Lestari et al (2015) using red microalgae raw materials with an intake of 300 liters produced 2305.5 liters of biogas for 72 days of observation. Novita et al (2019) conducted a study using coffee processing liquid waste produced average biogas of 83.57 mL/day.…”