Search Results (4)

The global challenge of food waste management poses severe environmental and public health risks. Traditional disposal methods, such as landfilling and incineration, exacerbate these issues. Decomposing food waste in landfills emits methane, a greenhouse gas 25 times more potent than CO₂, while landfill leachate contaminates soil and groundwater with hazardous pathogens and toxins. Additionally, improper waste disposal fosters microbial proliferation, posing severe health risks. Incineration, though commonly used, is inefficient due to the high moisture content of food waste, leading to incomplete combustion and further air pollution. Therefore, this review examines biodigesters as a sustainable alternative to traditional food waste disposal, assessing their effectiveness in mitigating environmental and health risks while promoting circular economy practices. It evaluates different biodigester designs, their operational scalability, and their economic feasibility across diverse global contexts. Through an analysis of case studies, this review highlights biodigesters’ potential to address localized waste management challenges by converting organic waste into biogas—a renewable energy source—and nutrient-rich digestate, a valuable natural fertilizer. The process reduces greenhouse gas emissions, improves soil health, and minimizes public health risks associated with microbial contamination. Various biodigester designs, including fixed-dome, floating-drum, and tubular systems, are compared for their efficiency and adaptability. Additionally, this review identifies key barriers to biodigester adoption, including feedstock variability, maintenance costs, and policy constraints, while also discussing strategies to enhance their efficiency and accessibility. This review is novel in its comprehensive approach, bridging the technological, environmental, and public health perspectives on biodigesters in food waste management. Unlike prior studies that focused on isolated aspects—such as specific case studies, policy analyses, or laboratory-scale evaluations—this review synthesizes the findings across diverse real-world implementations, offering a holistic understanding of biodigesters’ impact. By addressing knowledge gaps in terms of health risks, environmental benefits, and economic challenges, this study provides valuable insights for policymakers, researchers, and industry stakeholders seeking sustainable waste management solutions. Full article

Biodiesel is an emerging alternative fuel that is generally made from edible and non-edible oilseed crops. Jatropha curcus has a high potential for producing biodiesel, which yields 25–35% oil along with 75–65% solid byproduct, generally called a de-oiled cake. The present manuscript deals with the co-digestion of Jatropha de-oiled cake along with cattle dung (1:1 ratio) for biogas production in a floating-type biogas digester. The experimental study was carried out in a modified KVIC biogas plant of 6 cubic meter capacity for 60 days’ retention time under psychrophilic and mesophilic temperature conditions. During all the experiments, the total solid content of the slurry was maintained fixed at 10–12% by mixing 10 kg Jatropha de-oiled cake and 10 kg cattle dung with 80 kg water. The experimental results showed that the average specific biogas production of Jatropha de-oiled cake and cattle dung slurry was observed to be 0.216 m³/kg TS, 0.252 m³/kg VS and 0.287 m³/kg TS, 0.335 m³/kg VS, respectively, under the aforementioned conditions. Moreover, the biogas methane concentration was observed to be 62.33% to 69.16% under mesophilic temperature conditions compared to the psychrophilic temperature conditions, 65.21% to 69.15%, respectively. Furthermore, the average total volatile solids mass removal efficiency of feeding material in the abovementioned process was 7% higher under mesophilic temperature conditions than psychrophilic temperature conditions. Additionally, the results indicated that a total 588.8 kg of input volatile solids produced a total of 7306.56 MJ/m³ and 5177.88 MJ/m³ energy in 60 days under psychrophilic and mesophilic temperature conditions. On the basis of the results, it is concluded that Jatropha de-oiled cake may be a superior solution for improving biogas quality and composition as well as a value-added product, i.e., organic manure. Full article

Anaerobic digestion (AD) systems are prominent in low- and middle-income countries (LMICs), although their implementation within organic farms to enhance resource efficiency and “close the loop” has been limited. This paper thus reviewed existing literature on the potential of AD technologies as part of closed-loop rural family farming communities in LMICs. Data from eleven existing case studies matching this criterion was then collated to understand practical considerations of implementing and maintaining viable AD systems for small farmers. The case studies analyzed indicate that most, if not all, of the biogas produced in the AD process is used for household purposes such as cooking, lighting and heating. The AD systems are either based on the fixed biogas dome or the floating drum design, although the tubular flexible balloon model is mentioned as a low-cost alternative. Future research opportunities in this topic include studying the applicability of recommendations offered across different geographies, consideration of long-term sustainability and impact of biodigester technology, and sociocultural factors such as community ownership and indigenous practices. Full article

This review is a summary of different aspects of the design and operation of small-scale, household, biogas digesters. It covers different digester designs and materials used for construction, important operating parameters such as pH, temperature, substrate, and loading rate, applications of the biogas, the government policies concerning the use of household digesters, and the social and environmental effects of the digesters. Biogas is a value-added product of anaerobic digestion of organic compounds. Biogas production depends on different factors including: pH, temperature, substrate, loading rate, hydraulic retention time (HRT), C/N ratio, and mixing. Household digesters are cheap, easy to handle, and reduce the amount of organic household waste. The size of these digesters varies between 1 and 150 m³. The common designs include fixed dome, floating drum, and plug flow type. Biogas and fertilizer obtained at the end of anaerobic digestion could be used for cooking, lighting, and electricity. Full article