Related Experiment Video
Updated: May 28, 2026
07:34
Biogas Purification through the use of a Microalgae-Bacterial System in Semi-Industrial High Rate Algal Ponds
Published on: March 22, 2024
Batch and continuous biogas production from grass silage liquor
Jehad Abu-Dahrieh1, Angela Orozco, Elaine Groom
1CenTACat, Queen's University Belfast, Belfast BT9 5AG, Northern Ireland, UK.
Bioresource Technology
|October 14, 2011
Summary
Recirculating effluent during continuous anaerobic digestion of grass silage liquor boosts methane yield, even at higher organic loading rates (OLR). This process efficiently converts silage liquor into high-quality methane.
Area of Science:
- Biotechnology
- Environmental Science
- Chemical Engineering
Background:
- Anaerobic digestion is a key technology for renewable energy production.
- Grass silage liquor is a potential feedstock for biogas generation.
- Optimizing digester performance is crucial for maximizing methane yield.
Purpose of the Study:
- To investigate the effects of effluent recirculation on the continuous mesophilic anaerobic digestion of grass silage liquor.
- To determine the optimal organic loading rate (OLR) for methane production.
- To evaluate the methane yield and chemical oxygen demand (COD) removal efficiency.
Main Methods:
- Batch and continuous mesophilic anaerobic digestion experiments were conducted.
- Armfield digesters were used for the continuous process.
- The study varied the OLR and investigated the impact of effluent recirculation.
Main Results:
- Methane yield decreased with increasing OLR in reactors without effluent recirculation.
- Methane yield increased with increasing OLR in reactors with effluent recirculation.
- COD removal efficiency remained consistent across OLRs for both reactor types.
Conclusions:
- Effluent recirculation enhances methane yield from grass silage liquor, particularly at higher OLRs.
- Grass silage liquor can be effectively converted into a high-quality methane stream (70-80% purity).
- Methane yields of up to 0.385 m3 kg(-1) COD are achievable.
Related Concept Videos
01:14Batch vs Continuous Culture
Fermentation is a foundational biotechnological process used to produce pharmaceuticals, biofuels, enzymes, and food additives. Among industrial strategies, batch and continuous fermentation are the two most widely applied. Although both rely on microbial conversion of substrates into desired products, they differ markedly in operation, productivity, and suitability for specific applications.Batch fermentation occurs in a closed system in which nutrient media and inoculum are added at the...
01:27Production of Alcohol
Continuous fermentation is a key strategy in industrial ethanol production, particularly when efficiency, scalability, and high yields are essential. This approach allows for uninterrupted operation and optimized resource utilization. The primary feedstock, corn starch, undergoes enzymatic hydrolysis facilitated by α-amylase and glucoamylase. These enzymes break down the starch into fermentable sugars such as glucose, which are readily assimilated by fermentative microorganisms.Fermentation...
01:25Production of Organic Acids
Lactic acid, an important organic acid extensively applied in food, pharmaceutical, and biodegradable polymer industries, is primarily produced via microbial fermentation. This method is favored over chemical synthesis due to its environmental sustainability and capacity for enantiomerically pure product formation. Among various microbial processes, the fermentation of starch-based substrates stands out due to the abundance and renewability of raw materials like corn and potatoes.Hydrolysis of...
01:18Bioreactor Controls-II
In aerobic fermentations, oxygen is vital for microbial growth and metabolite production. Since air comprises only about 20% oxygen and the gas is poorly soluble in water—just 9 ppm at 20°C—supplying sufficient oxygen becomes a critical challenge, especially in high-demand processes like yeast growth or citric acid production. Even a fully saturated broth may offer only a few seconds of oxygen availability.To address this, sterile or scrubbed air is introduced into the fermentor via a sparger...
01:27Microbes in the Production of Fermented Foods
Lactic acid bacteria (LAB) and molds are instrumental in fermenting plant-based foods to enhance preservation and ensure year-round availability. These microbial processes convert plant carbohydrates into organic acids and other metabolites that inhibit spoilage organisms and contribute to the sensory qualities of the final product.In sauerkraut production, cabbage goes through a microbial succession that starts with cocci such as Leuconostoc mesenteroides. These microbes begin fermentation by...
01:14Scale-Up Processes
The scale-up of microbial fermentation processes is essential in industrial biotechnology, allowing the transition from laboratory-scale experiments to commercial-scale production while aiming to maintain product yield and quality. This process requires meticulous adjustment of equipment design, process parameters, and contamination control strategies to accommodate increasing culture volumes.At the laboratory scale, cultures are typically maintained in 1 to 10-liter glass or autoclavable...