•Reviewed resource recovery from organic solid waste towards bio-circular economy.•Aerobic and anaerobic digestion technology: a sustainable approach for biorefinery.•Organic solid waste: a potential ...biorefinery and bio-economy option.
With the inevitable rise in human population, resource recovery from waste stream is becoming important for a sustainable economy, conservation of the ecosystem as well as for reducing the dependence on the finite natural resources. In this regard, a bio-based circular economy considers organic wastes and residues as potential resources that can be utilized to supply chemicals, nutrients, and fuels needed by mankind. This review explored the role of aerobic and anaerobic digestion technologies for the advancement of a bio-based circular society. The developed routes within the anaerobic digestion domain, such as the production of biogas and other high-value chemicals (volatile fatty acids) were discussed. The potential to recover important nutrients, such as nitrogen through composting, was also addressed. An emphasis was made on the innovative models for improved economics and process performance, which include co-digestion of various organic solid wastes, recovery of multiple bio-products, and integrated bioprocesses.
Anaerobic digestion (AD) is a well-established technology used for producing biogas or biomethane alongside the slurry used as biofertilizer. However, using a variety of wastes and residuals as ...substrate and mixed cultures in the bioreactor makes AD as one of the most complicated biochemical processes employing hydrolytic, acidogenic, hydrogen-producing, acetate-forming bacteria as well as acetoclastic and hydrogenoclastic methanogens. Hydrogen and volatile fatty acids (VFAs) including acetic, propionic, isobutyric, butyric, isovaleric, valeric and caproic acid and other carboxylic acids such as succinic and lactic acids are formed as intermediate products. As these acids are important precursors for various industries as mixed or purified chemicals, the AD process can be bioengineered to produce VFAs alongside hydrogen and therefore biogas plants can become biorefineries. The current review paper provides the theory and means to produce and accumulate VFAs and hydrogen, inhibit their conversion to methane and to extract them as the final products. The effects of pretreatment, pH, temperature, hydraulic retention time (HRT), organic loading rate (OLR), chemical methane inhibitions, and heat shocking of the inoculum on VFAs accumulation, hydrogen production, VFAs composition, and the microbial community were discussed. Furthermore, this paper highlights the possible techniques for recovery of VFAs from the fermentation media in order to minimize product inhibition as well as to supply the carboxylates for downstream procedures.
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•Effectiveness of bamboo biochar on nutrient conservation was studied in composting.•Bamboo biochar (BB) notably elevated enzymes activities during co-composting.•Biochar amendment ...has positive and significant influence of C and N preservation.•Gaseous and environmental factors had intensively correlation with intersection of 68.81%.•10% BB addition has lowest C and N losses with 148.89% and 12.59%.
The effectiveness of specific concentrations of bamboo biochar (BB) on nutrient conservation based on gaseous emissions during poultry manure composting was investigated. The results indicate that the total carbon and nitrogen losses were significantly reduced with elevated of biochar from 542.8 to 148.9% and 53.5 to 12.6% (correspondingly with an additive of 0%, 2%, 4%, 6% and 8% to 10% BB dry weight based). The primary contributor was CO2 and NH3 losses (542.3–148.8% and 47.8–10.81%). The enzyme activities related to carbon and nitrogen metabolism indicated a positive and significantly enhanced with high concentration biochar amended composting. Simultaneously, the alteration of total organic carbon and total Kjeldahl nitrogen as well as maturity indexes during ultimate compost also confirmed a high quality product under higher content biochar amended composting. Carbon and nitrogen were best preserved with 10%BB and produced a superior final product. The analysis of a network and heat map illustrated the correlation of gaseous and physicochemical elements as well as enzyme activities, with an intersection of 68.81%.
•Relative abundance of bacterial was richer in 6% pig manure biochar composting.•Phylogenetic tree and krona have confirmed the bacterial diversity variation.•Bacterial community had distinctive ...distribution among all five composts.•Biochar additive affected bacterial metabolism related to organic waste degradation.
The influence of pig manure biochar amendment (PMBA) during the pig manure (PM) and wheat straw (WS) composting was evaluated. Five concentration of PMBA (0%, 2%, 4%, 6% and10%) were applied to explore the bacterial distributions in PM compost by 16SDNA amplicons sequencing. The results showed that the addition of 6% PMBA could significantly enhanced the bacterial community abundance compared with other composts, while control has relative less bacterial population (332 OTU). The visualization of phylogenetic tree and krona demonstrated the distinctive distribution of each composts, suggested that biochar dosages have an influence on bacterial communities’ variation during co-composting. Beta-diversity of distance matrix heat-map and principal component analysis confirmed that bacterial communities were considerably correlated with increasing PMBA. Redundancy also confirmed the similarity and discrepancy among all treatments and environmental factors. This work considered as the potential of PMBA as a booster in composting, where T4 has most plentiful bacterial community and diversity.
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•Influence of biochar and bacterial inoculum amendment on cow dung composting was studied.•12% WSB and bacterial consortium (BC) has lowest carbon and nitrogen loss.•12% WSB and BC ...has highest bacterial population and degraded efficiency.•12%WSB + BC amendment is superior option for cow manure composting.•12%WSB + BC showed strong interrelation between bacterial community and physicochemical factors.
The present study evaluates the effectiveness of different types of biochar additives and bacterial inoculation on gaseous emission, nutrient preservation, and relevant functional bacterial community during cow manure composting. The result revealed that biochar and bacterial consortium inoculation effectively inhibited gaseous emission and improved carbon and nitrogen sequestration, remarkably enriching the abundance of the functional bacteria community. Notably, superior efficacy was found in 12% wheat straw biochar and bacterial consortium amendment composting of T6 with the lowest cumulative CO2-C and NH3-N (308.02 g and 12.71 g, respectively), minimal total C and N losses, and the highest bacterial population. Additionally, gaseous emission exhibited a strong correlation between physicochemical properties with intersection of 66.78% and a unique substrate utilizing bacterial communities. Consequently, the integrated application of biochar and bacterial consortium inoculation was suggested as an efficient method to adjust microbial activity and facilitate cellulose-rich waste degradation, enabling efficient management of organic waste from cow manure and wheat straw by composting.
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•Chicken manure biochar and combined with microorganism culture was studied for chicken manure composting.•CMB and CMMC addition promoted the organic matter degradation and reduced ...the period of maturity.•Chicken manure biochar addition reduced the greenhouse gases and ammonia emission.•Chicken manure biochar improved the quality of end product.
The effects of chicken manure biochar (CMB) and chicken manure integrated microbial consortium (CMMC) as co-amendments were assessed on compost maturity and reduction of greenhouse gases and ammonia (NH3) emissions during chicken manure composting. Composting was conducted using six combinations of CMB and CMCC (0 % CMB + 0 % CMMC, 0 % CMB + 10 % CMMC, 2 % CMB + 10 % CMMC, 4 % CMB + 10 % CMMC, 6 % CMB + 10 % CMMC, 10 % CMB + 10 % CMMC added on a dry weight basis) in six polyvinyl chloride composting reactors for 42 days under an aerobic environment. Co-amendment of CMB and CMMC extended the thermophilic stage and promoted compost maturity. The release of greenhouse gases nitrous oxide (N2O) and methane (CH4) and NH3 from treatments co-amended by CMB and CMMC were reduced by 19.0–27.4 %, 9.3–55.9 % and 24.2–56.9 %, respectively, compared with the control. In addition, a redundancy analysis showed that the C/N ratio and temperature had a significant relationship with greenhouse gases and NH3 emissions among all physiochemical characteristics.
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•Biodiesel is a renewable and ecofriendly biofuel.•It can be produced using transesterification, emulsification and pyrolysis process etc.•Enzyme catalyzed and biomass derived ...catalysts reactions are economic and ecofriendly.•Process intensification technology results in higher yield with lower wastes.
Biodiesel is a non-toxic renewable energy source that is gaining attention globally owing to its direct applicability in preexisting engines without any modification. Various technologies from laboratory scale to industrial scale have been developed, and many plants have been established for biodiesel production using various feedstocks. Using biobased technology in biodiesel production is advantageous as these methods generate less waste and are considered ecofriendly. This article mainly discusses the availability of various oil resources (edible, non-edible, waste cooking oils (WCO)) and the advancements in technology related to oil extraction. Specifically, biobased methods, such as immobilized enzymes (matrix) and heterogeneous catalysts (derived from biomass), reported to catalyze the transesterification reaction for biodiesel production are discussed in detail. Biodiesel production using conventional technologies results in low yield and purity and is time-consuming. Newly introduced process intensification technologies (microreactor, membrane reactor, microwave, reactive distillation, and centrifugal contractor) to overcome these issues are also discussed. The need to develop integrated process technologies for biodiesel production to make the process more economical is emphasized.
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•The challenges and opportunities for food waste (FW) composting were overviewed.•FW composting microbiological variations are explained.•Microbiology of FW composting has been ...studied with novel molecular tools.•Gaseous emissions reduction during FW composting were evaluated.•The global policy and legislation for food waste management were reviewed.
Increasing food waste (FW) generation has put significant pressure on the environment and has increased the global financial costs of its appropriate management. Among the traditional organic waste recycling technologies (i.e., incineration, landfilling and anaerobic digestion), composting is an economically feasible and reliable technology for FW recycling regardless of its technical flaws and social issues. The global scenario of FW generation, technical advancement in FW composting and essential nutrient recovery from organic waste with waste recycling are discussed in this article. Recent research on various strategies to improve FW composting, including co-composting, the addition of organic/inorganic additives, the mitigation of gaseous emission, and microbiological variations are comprehensively explained. Subsequently, it is shown that the performing FW composting in an existing mechanical facility can improve organic waste degradation and produce value-added mature compost to save on costs and increase the technological feasibility and viability of FW composting to some extent.
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•This review explores the potential of using a wide range of apple orchard waste (AOW).•Thermochemical and biological processes were assess towards to circular bioeconomy.•This review ...explores the potential for the use of AOW to produce multi bio-products.•The nature of AOW role in achieving successful circular bio economy is also highlighted.•Sustainable interventions with biorefineries approaches still need look for AOW.
In this review investigate the apple orchard waste (AOW) is potential organic resources to produce multi-product and there sustainable interventions with biorefineries approaches to assesses the apple farm industrial bioeconomy. The thermochemical and biological processes like anaerobic digestion, composting and , etc., that generate distinctive products like bio-chemicals, biofuels, biofertilizers, animal feed and biomaterial, etc can be employed for AOW valorization. Integrating these processes can enhanced the yield and resource recovery sustainably. Thus, employing biorefinery approaches with allied different methods can link to the progression of circular bioeconomy. This review article mainly focused on the different biological processes and thermochemical that can be occupied for the production of waste to-energy and multi-bio-product in a series of reaction based on sustainability. Therefore, the biorefinery for AOW move towards identification of the serious of the reaction with each individual thermochemical and biological processes for the conversion of one-dimensional providences to circular bioeconomy.
The increasing number of livestock farms has led to a great deal of manure generation, and its improper treatment results in threats to the environment. Black soldier fly larvae (BSFL) have the ...potential to effectively convert manure into high-quality fertilizer. The aims of this investigation were to observe the organic matter transformation of different livestock manures and volatile fatty acids (VFAs), and to evaluate the end product quality. Three types of manure chicken (T1), pig (T2), and cow (T3) were inoculated with BSFL (1.2:7 ratio on fresh weight basis), three types without BSFL were used as control (T4, T5, and T6), and both were composted for 9 days. The results showed that the BSFL composting reduced the organic matter by 20.31–22.18% and the accumulation of VFAs by 25.58–80.08% as compared to the control. BSFL composting greatly decreased the nitrogen, by 6.08–14.37%. The employment of BSFL significantly increased the total phosphorous (TP), total Kjeldahl nitrogen (TKN), and total nutrients by 42.30–64.16%, 45.41–88.17%, and 26.51–33.34%, respectively. This study showed that employing BSFL could improve the quality of the product and the maturity degree of the composting. Therefore, the BSFL could be added as a high-efficiency transformation agent for converting organic manure into stable compost, especially in developing countries, where adopting technical devices for composting is expensive and difficult to manipulate.
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•Black soldier fly larvae was applied as an inoculum for different manure composting.•Black soldier fly larvae inoculation improved total nutrient and organic matter degradation.•The addition of black soldier fly reduced the accumulation of volatile fatty acids.•Black soldier fly larvae accelerate the process and improved final compost quality.
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