Techno-economic assessment of bioenergy and fertilizer production by anaerobic digestion of brewer’s spent grains in a biorefinery concept

The paper deals with the performances of the mesophilic anaerobic digestion treatment of sewage sludge from a full scale BNR process without primary settling (nominally 300,000 PE). A relation between the activated sludge observed yields, Yobs, and the anaerobic digester performance was preliminarily found: for values of Yobs of 0.25 kgVSS/kgCOD the anaerobic digester specific gas production showed the best performances (0.22 m3/kgVSfed). This has to be confirmed with wider future studies. It was also shown the level of sludge pre-thickening to be reached for the self-sustaining warming of the digester also in wintertime. According to the energetic balance and to a comparison with an aerobic stabilisation process, it was pointed out as when a co-generation unit for heat and energy production was introduced about 3.4 kWh/PE y of energy were produced in the anaerobic digestion process. On the other hand, 4.3 kWh/PE y were spent if an aerobic stabilisation process was applied. The economic assessment, carried out on the basis of the energy balances, showed that the anaerobic digestion is always economically advantageous if compared to aerobic stabilisation processes, also for small WWTPs. According to the energetic evaluations an environmental balance was assessed, in terms of CO2 emissions. The difference between anaerobic and aerobic processes was about 5.3 kgCO2/PE y in favour of anaerobic processes application.

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Influence of Ultrasound on the Synthesis of Biogas During Disposal of Beer Spent Grain

Beer and beverages ◽

10.52653/pin.2021.2.2.001 ◽

2021 ◽

pp. 33-38

Author(s):

Владимир Владимирович Житков ◽

Борис Николаевич Федоренко

Keyword(s):

Anaerobic Digestion ◽

Energy Production ◽

Biogas Production ◽

Organic Substances ◽

Ultrasonic Pretreatment ◽

Biogas Yield ◽

Spent Grains ◽

Efficient Resource ◽

Spent Grain ◽

Environmentally Friendly Process

Ультразвуковая предварительная обработка считается экологически чистым процессом для повышения биоразлагаемости органических веществ при анаэробном сбраживании. Однако количество потребляемой энергии во время предварительной обработки является проблемой, особенно в тех случаях, когда производство энергии является основной целью биогазовой установки. Основной целью настоящего исследования работы было изучение эффективности ультразвуковой предварительной обработки для увеличения производства биогаза из отходов пивоваренного производства - пивной дробины. Результаты показали, что применение частоты 40 кГц при температуре 40 °С соответственно привело к увеличению выхода биогаза на 83%. Методология показала положительный результат в отношении содержания метана и скорости производства биогаза. Использование ультразвуковой предварительной обработки в отношении пивоваренной дробины для производства биогаза, по-видимому, позволяет решить проблемы не только эффективной утилизации пивоваренных отходов, но и создать экономически эффективный ресурс возобновляемой энергии на пивоваренном или аффилированном с ним производстве. Ultrasonic pretreatment is considered an environmentally friendly process to increase the biodegradability of organic substances during anaerobic digestion. However, the amount of energy consumed during pretreatment is a problem, especially in cases where energy production is the main purpose of the biogas plant. The main purpose of this study was to study the effectiveness of ultrasonic pretreatment to increase the production of biogas from brewing waste - brewer's grains. The results showed that the use of a frequency of 40 kHz at a temperature of 40 °C, respectively, led to an increase in the biogas yield by 83%. The methodology showed a positive result in terms of methane content and biogas production rate. The use of ultrasonic pretreatment for brewing spent grains for biogas production seems to solve the problems of not only efficient disposal of brewing waste, but also to create an economically efficient resource of renewable energy in brewing or its affiliated production.

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