Microbes as vital additives for solid waste composting

Biochar and pyroligneous acid contributed to the sustainable reduction of ammonia emissions: From compost process to soil application

Aerobic composting is vital for resource recycling but struggles with high ammonia (NH3) emissions. Biochar (BC) and pyroligneous acid (PA), products of waste pyrolysis, have great potential for reducing NH3 emissions. However, the effective utilization of BC and PA to reduce NH3 emissions in both compost process and product application remains unclear. In this study, different amounts of BC and PA were incorporated into the composting process. The evaluation indexes of compost products were systematically assessed and compared through the cultivation of amaranth. Results demonstrated that rational use of BC and PA could enhance compost quality and effectively reduce NH3 emissions. The addition of 15 %BC+ 3 %PA resulted in a 92.31 % increase in NH4+-N content while reducing NH3 emission by 39.94 % during composting. The synergistic effect achieved by maintaining NH4+-N, enhancing NO3--N, and regulating pH. The compost products in 15 %BC+ 3 %PA complied with the requirements of China's National organic fertilizer standard. Moreover, these compost products demonstrated soil sustained fertility effects, reducing NH3 emission by 41.05 %-69.66 % and increasing total weight of amaranth by 4.62 % by a dosage of 4 %. This study is highly significant for addressing the issue of NH3 emission in both the compost process and soil application.

New insights into Peniophora crassitunicata and its co-inoculation with commercial microbial inoculant accelerating lignocellulose degradation and compost maturation during orchard wastes composting

Lignocellulosic composting has been widely promoted in the utilization of agricultural wastes, while few focus on orchard lignocellulosic wastes in the fruit industry. Peniophora is a laccase hyper-producer highly efficient in lignin degradation, yet its application in lignocellulosic composting has not been investigated. Here, an aerobic composting experiment was conducted to investigate the effects of inoculation with Peniophora crassitunicata and a commercial microbial inoculant (mainly Bacillus and Aspergillus) on grape (Vitis Vinifera L.) orchard lignocellulosic wastes degradation and the underlying mechanisms. The inoculation with P. crassitunicata, both individually (H) and in combination with the commercial microbial inoculant (HS), enhanced lignocellulose degradation efficiency. Notably, the co-inoculation exhibited higher lignocellulose degradation ratios and higher lignocellulosic enzyme activities compared to other treatments. The compost piles with co-inoculation experienced a more rapid temperature rise, a longer duration (15 days) of high temperatures, lower pH, and lower electrical conductivity (EC). Firmicutes (e.g. Bacillus, Paenibacillus) and Ascomycota (e.g. Aspergillus) along with Bacteroidota, Actinobacteriota, and Basidiomycota (e.g. Peniophora) dominated the microbial community in compost; carbohydrate metabolism dominated microbial metabolic pathways at the thermophilic phase, highlighting an active microbial community. As compost processed, highly mature and non-toxic compost products were finally obtained for the co-inoculation, with a pH of 7.87, C/N ratio of 13.5, NH4+-N/NO3‾-N ratio of 0.21-0.41, EC of 0.90 mS cm-1, and germination index of 149 %. The co-inoculation of P. crassitunicata with the commercial microbial inoculant effectively accelerated lignocellulose degradation and compost maturation, producing a friendly and non-toxic organic fertilizer for agricultural applications and thereby providing a new strategy for orchard wastes management and agricultural applications.

Optimizing green waste composting with Bacillus siamensis inoculant: Impacts on decomposition and microbial dynamics

The use of microbial inoculants has emerged as a promising strategy to improve the efficiency of green waste (GW) composting. This study evaluated the effects of inoculating compost with an indigenous Bacillus siamensis inoculant (T1), a commercial effective microorganism (EM) inoculant (T2), and a non-inoculated control (T3), under light conditions excluding blue light. The T1 treatment resulted in a significantly higher peak temperature (65.8 °C) and an extended thermophilic phase (12 days), reducing the overall composting duration to 35 days, compared with 37 days for T2 (61.2 °C; 9 days) and 39 days for T3 (58.4 °C; 6 days). The T1 also markedly enhanced the degradation of key organic components (achieving reductions of 60.6 % in organic matter, 43.2 % in lignin, 51.0 % in cellulose, and 44.5 % in hemicellulose), outperforming both T2 and T3 by 6.9-37.6 percent. Compost quality under T1 was significantly enhanced, with elevated levels of total nitrogen, nitrate nitrogen, total and available phosphorus, and total and available potassium, alongside enhanced structural stability, water-holding capacity, and porosity. High-throughput microbial analyses revealed that T1 significantly enriched functional microbial taxa such as Bacillus, Aspergillus, and Thermomyces, resulting in a more functionally optimized community structure. Functional prediction further indicated phase-specific enhancement of enzymatic activity, with bacterial enzymes predominantly enriched during the mesophilic phase and fungal enzymes during the thermophilic phase. These findings provide mechanistic insights into the synergistic effects of microbial inoculation on organic matter decomposition and nutrient transformation, offering a practical framework for value-added GW composting through targeted microbial intervention.

Synthetic microbial community enhances lignocellulose degradation during composting by assembling fungal communities

Inoculating synthetic microbial community (SynCom) has been proposed as an eco-friendly approach for lignocellulose degradation in composting to enhance organic fertilizer quality. However, the mechanisms responsible for SynCom-regulated lignocellulose degradation during composting remain unclear. Here the SynCom inoculation decreased cellulose and hemicellulose contents by 26.2% and 14.3%, respectively, at the mature phase, while increasing endoglucanase, exoglucanase, and β-glucosidase activities significantly. SynCom inoculation increased the abundance of Cephaliophoras and Thermomyces at the mesophilic phase, Sordariomycetes at the thermophilic phase, and Thermomyces, Acremonium, Aspergillus, and Sordariomycetes at the mature phase, as well as increased the abundance of numerous Operational Taxonomic Units (OTUs), with OTU10 (Hydropisphaera) being responsible for lignocellulose degradation. The altered fungal community stimulated functions of the wood saprotroph, undefined saprotroph, and litter saprotroph were responsible for lignocellulose degradation via changing microbial community. The results suggest that SynCom inoculation effectively stimulate lignocellulose degradation, so that benefits quality improvement of organic fertilizer.

Seasonal and diurnal changes of pCO2 in the lower Brahmaputra River, Bangladesh

Monthly 24-h real-time high-resolution monitoring was conducted for 1 year to investigate the carbon dioxide (CO2) dynamics in the lower Brahmaputra River. The partial pressure of CO2 (pCO2) was observed between 136 and 1213 µatm. The pCO2 was almost 1.5 times higher during the wet season (May-October) than during the dry season (November-April). Diurnal variation in pCO2 was pronounced during the dry season. In contrast, no clear diurnal pattern was observed during the wet season. The combined measurements of O2-CO2 in river water provide insights into net chemical and microbial activity. In January and March, there was a bidirectional exchange of CO2, occurring from air to water (sink) and from water to air (source). However, in April, the CO2 exchange was unidirectional, taking place solely from air to water, whereas in all other months, it occurred from water to air. The carbon dioxide flux (FCO2) in the river ranged from - 31.12 to 137.74 mmol m-2 day-1, with an average of 25.26 mmol m-2 day-1 during the dry season and 78.56 mmol m-2 day-1 in the wet season. This flux significantly contributes to the regional net carbon budget of the world's largest delta.

Promoting effect of ammonia oxidation on sulfur oxidation during composting: Nitrate as a bridge

Ammonia (NH3) and hydrogen sulfide (H2S) are the main odor components in the composting process. Controlling their emissions is very important to reduce environmental pollution and improve the quality of composting products. This study explored the effects of functional bacteria on nitrogen and sulfur metabolism in the composting process of food waste (FW) by adding ammonia-oxidizing bacteria (AOB, A treatment), sulfur-oxidizing bacteria (SOB, S treatment), and combined AOB and SOB (AS treatment), respectively. The key bacterial species involved in nitrogen and sulfur transformation were identified, and the intrinsic mechanisms by which ammonia oxidation drove sulfur oxidation during composting were deciphered. Compared with control treatment (CK), the combined addition of functional microorganisms increased the maximum of soxB gene abundance by 1.72 times, thus resulting in the increase in the SO42- content by 44.00 %. AS treatment decreased the cumulative H2S emission and total sulfur (TS) loss by 40.24 % and 34.69 %, respectively, meanwhile lowering NH3 emission. Correlation network analysis showed that the simultaneous addition of AOB and SOB enhanced the correlation between microorganisms and sulfur oxidation genes, and Acinetobacter, Aeribacillus, Brevibacterium and Ureibacillus might be involved in the ammonia oxidation-promoted sulfur oxidation process. In summary, the optimized inoculation strategy of AOB and SOB could drive biological transformation of nitrogen and sulfur by regulating microbial community, ultimately reducing odor emissions and improving sulfur conservation.

Investigating the inhibitory mechanism of methanogenesis during composting under the combined influence of amoxicillin and copper pollution

This study investigated the effects of different levels of combined amoxicillin and copper (Cu) pollution on the methanogenesis of microbial communities during aerobic composting of dairy manure. Three groups were established: the control group (CK), a low-level combined pollution group (L), and a high-level combined pollution group (H). As the level of pollution increased, carbohydrate metabolism decreased during the thermophilic phase of composting, while signal translation increased. Compared with the initial phase, functional genes related to the acetoclastic pathway decreased significantly in abundance during the thermophilic phase, and cdh had the lowest relative abundance among acetoclastic pathway with a decrease of 81.52%, 81.88%, and 84.73% in groups CK, L, and H, respectively. The cumulative methane emissions in group H decreased by 31.56% and 9.23%, respectively, compared with those from groups CK and L. These results contribute to understanding the effects of combined amoxicillin and Cu pollution on methane emissions during composting.

The dawn of ethnomicrobiology: an interdisciplinary research field on interactions between humans and microorganisms

BACKGROUND

Ethnobiologists commonly analyze local knowledge systems related to plants, animals, fungi, and ecosystems. However, microbes (bacteria, yeasts, molds, viruses, and other organisms), often considered invisible in their interactions with humans, are often neglected. Microorganisms were the earliest life forms on Earth, and humans have interacted with them throughout history. Over time, humans have accumulated ecological knowledge about microbes through attributes such as smell, taste, and texture that guide the management of contexts in which microorganisms evolve. These human-microbe interactions are, in fact, expressions of biocultural diversity. Thus, we propose that ethnomicrobiology is a distinct interdisciplinary field within ethnobiology that examines the management practices and knowledge surrounding human-microbe interactions, along with the theoretical contributions that such an approach can offer.

METHODS

We reviewed scientific journals, books, and chapters exploring human-microbe relationships. Our search included databases such as Web of Science, Scopus, Google Scholar, and specific journal websites, using keywords related to ethnomicrobiology and ethnozymology. To categorize activities involving deliberate human-microbial interactions, we examined topics such as fermentation, pickling, food preservation, silaging, tanning, drying, salting, smoking, traditional medicine, folk medicine, agricultural practices, composting, and other related practices.

RESULTS

Our research identified important precedents for ethnomicrobiology through practical and theoretical insights into human-microbe interactions, particularly in their impact on health, soil, and food systems. We also found that these interactions contribute to biodiversity conservation and co-evolutionary processes. This emerging interdisciplinary field has implications for food ecology, public health, and the biocultural conservation of hidden microbial landscapes and communities. It is essential to explore the socioecological implications of the interwoven relationships between microbial communities and humans. Equally important is the promotion of the conservation and recovery of this vast biocultural diversity, along with sustainable management practices informed by local ecological knowledge.

CONCLUSION

Recognizing the dawn of ethnomicrobiology is essential as the field evolves from a descriptive to a more theoretical and integrative biological approach. We emphasize the critical role that traditional communities have played in conserving food, agriculture, and health systems. This emerging field highlights that the future of ethnobiological sciences will focus not on individual organisms or cultures, but on the symbiosis between microorganisms and humans that has shaped invisible but often complex biocultural landscapes.

Synergistic improvement of humus formation in compost residue by fenton-like and effective microorganism composite agents

Improving the humification of compost through a synergistic approach of biotic and abiotic methods is of great significance. This study employed a composite reagent, comprising Fenton-like agents and effective microorganisms (EM) to improve humification. This composite reagent increased humic-acid production by 37.44 %, reaching 39.82 g kg-1, surpassing the control group. The composite reagent synergistically promoted micromolecular fulvic acid and large humic acid production. Collaborative mechanism suggests that Fenton-like agents contributed to bulk residue decomposition and stimulated the evolution of microbial communities, whereas EMs promoted highly aromatic substance synthesis and adjusted the microbial community structure. Sequencing analysis indicates the Fenton-like agent initiated compost decomposition by Firmicutes, and EM reduced the abundance of Virgibacillus, Lentibacillus, and Alcanivorax. Applied as an organic fertilizer in Brassica chinensis L. plantations, the composite reagent considerably improved growth and photosynthetic pigment content. This composite reagent with biotic and abiotic components provides a learnable method for promoting humification.

Investigating fungal community characteristics in co-composted cotton stalk and various livestock manure products

Agricultural wastes, comprising cotton straw and livestock manure, can be effectively managed through aerobic co-composting. Nevertheless, the quality and microbial characteristics of co-composting products from different sources remain unclear. Therefore, this study utilized livestock manure from various sources in Xinjiang, China, including herbivorous sheep manure (G), omnivorous pigeon manure (Y), and pigeon-sheep mixture (GY) alongside cotton stalks, for a 40-day co-composting process. We monitored physicochemical changes, assessed compost characteristics, and investigated fungal community. The results indicate that all three composts met established composting criteria, with compost G exhibiting the fastest microbial growth and achieving the highest quality. Ascomycota emerged as the predominant taxon in three compost products. Remarkably, at the genus level, the biomarker species for G, Y, and GY are Petromyces and Cordyceps, Neurospora, and Neosartorya, respectively. Microorganisms play a pivotal role in organic matter degradation, impacting nutrient composition, demonstrating significant potential for the decomposition and transformation of compost components. Redundancy analysis indicates that potassium, total organic carbon, and C:N are key factors influencing fungal communities. This study elucidates organic matter degradation in co-composting straw and livestock manure diverse sources, optimizing treatment for efficient agricultural waste utilization and sustainable practices.

Development of functional consortia for the pretreatment of compostable lignocellulosic waste: A simple and effective solution to a large-scale problem

Microorganisms drive the degradation of organic matter thanks to their enzymatic versatility. However, the structure of lignocellulose poses a great challenge for the microbiota inhabiting a compost pile. Our purpose was to increase the biodegradability of vegetable waste in the early stages of the composting process by applying a microbial consortium with lignocelllulolytic capacity. For this, a previous screening was performed among the culturable microbiota from different composting processes to find inoculants with ligninocellulolytic activity. Selected strains were applied as a pure culture and as a microbial consortium. The starting material was composed of tomato plant and pruning remains mixed in a ratio (50:50 v/v), whose humidity was adjusted to around 65%. To determine the ability of both treatments to activate the biodegradation of the mixtures, moisture, organic matter, ash, C/N ratio, 4-day cumulative respirometric index (AT4) and degradation rates of cellulose, hemicellulose and lignin were evaluated. Subsequently, a real composting process was developed in which the performance of the microbial consortium was compared with the composting process without inoculum (control). According to our tests, three microbial strains (Bacillus safensis, Bacillus licheniformis and Fusarium oxysporum) were selected. The results showed that the application of the bacteria strains at low doses (104 CFU g-1 on the complete residual material of the pile) resulted in higher rates of lignocelullose degradation after 10 days of treatment compared to that observed after application of the fungus in pure culture or untreated controls. The implementation of the strategy described in this work resulted in obtaining compost with better agronomic quality than the uninoculated controls. Therefore, the application of this consortium could be considered as an interesting tool for bioactivation of lignocellulosic waste prior to the composting process.

Sustainable management and valorization of biomass wastes using synthetic microbial consortia

In response to the persistent expansion of global resource demands, considerable attention has been directed toward the synthetic microbial consortia (SMC) within the domain of microbial engineering, aiming to address the sustainable management and valorization of biomass wastes. This comprehensive review systematically encapsulates the most recent advancements in research and technological applications concerning the utilization of SMC for biomass waste treatment. The construction strategies of SMC are briefly outlined, and the diverse applications of SMC in biomass wastes treatment are explored, with particular emphasis on its potential advantages in waste degradation, hazardous substances control, and high value-added products conversion. Finally, recommendations for the future development of SMC technology are proposed, and prospects for its sustainable application are discussed.

Recent Trends and Advances in Additive-Mediated Composting Technology for Agricultural Waste Resources: A Comprehensive Review

Agriculture waste has increased annually due to the global food demand and intensive animal production. Preventing environmental degradation requires fast and effective agricultural waste treatment. Aerobic digestion or composting uses agricultural wastes to create a stabilized and sterilized organic fertilizer and reduces chemical fertilizer input. Indeed, conventional composting technology requires a large surface area, a long fermentation period, significant malodorous emissions, inferior product quality, and little demand for poor end results. Conventional composting loses a lot of organic nitrogen and carbon. Thus, this comprehensive research examined sustainable and adaptable methods for improving agricultural waste composting efficiency. This review summarizes composting processes and examines how compost additives affect organic solid waste composting and product quality. Our findings indicate that additives have an impact on the composting process by influencing variables including temperature, pH, and moisture. Compost additive amendment could dramatically reduce gas emissions and mineral ion mobility. Composting additives can (1) improve the physicochemical composition of the compost mixture, (2) accelerate organic material disintegration and increase microbial activity, (3) reduce greenhouse gas (GHG) and ammonia (NH3) emissions to reduce nitrogen (N) losses, and (4) retain compost nutrients to increase soil nutrient content, maturity, and phytotoxicity. This essay concluded with a brief summary of compost maturity, which is essential before using it as an organic fertilizer. This work will add to agricultural waste composting technology literature. To increase the sustainability of agricultural waste resource utilization, composting strategies must be locally optimized and involve the created amendments in a circular economy.

The integrated study of the effects of infographic design on waste separation behavior and the behavioral outcome implementation on waste composting

This study revealed the effects of designed infographics for waste separation and the implementation of behavioral outcomes using surveys and lab-scale experiments. The designed infographics improved the waste separation behaviors of the respondents in term of subject norm, perceived behavioral control, and intention. These influential factors were increased by 5.84 to 20.5%. The effects of design elements including waste separation mascots, the knowledge of waste separation, and the knowledge of waste management were dependent on the ratio of graphics and messages. Therefore, the careful attention on design elements of the infographic had to be noted. According to survey results, animal bone and shell wastes were the highest miss-sorting waste for the compostable waste bin. Although the contamination rate of these wastes did not significantly affect the decomposition of organic waste in the composting process, the quality of the product was degraded in term of toxicity. The germination index was decreased by 66.0% under a 10% contaminated condition. In contrast, the increased the total Ca of compost was increased. Furthermore, the other chemical components of final composts were similar under various conditions. It could be concluded that the mixture of animal bone and shell in compostable waste is acceptable for the purpose of waste reduction. However, the contamination rate of inappropriate wastes in the compostable waste bin should be minimized to enable effective waste composting. The significant findings of this study will be able to apply to the design of waste separation at the source and the plan of waste management.

Black soldier fly (Diptera: Stratiomyidae) larval heat generation and management

Mass production of black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae), larvae results in massive heat generation, which impacts facility management, waste conversion, and larval production. We tested daily substrate temperatures with different population densities (i.e., 0, 500, 1000, 5000, and 10 000 larvae/pan), different population sizes (i.e., 166, 1000, and 10 000 larvae at a fixed feed ratio) and air temperatures (i.e., 20 and 30 °C) on various production parameters. Impacts of shifting larvae from 30 to 20 °C on either day 9 or 11 were also determined. Larval activity increased substrate temperatures significantly (i.e., at least 10 °C above air temperatures). Low air temperature favored growth with the higher population sizes while high temperature favored growth with low population sizes. The greatest average individual larval weights (e.g., 0.126 and 0.124 g) and feed conversion ratios (e.g., 1.92 and 2.08 g/g) were recorded for either 10 000 larvae reared at 20 °C or 100 larvae reared at 30 °C. Shifting temperatures from high (30 °C) to low (20 °C) in between (∼10-d-old larvae) impacted larval production weights (16% increases) and feed conversion ratios (increased 14%). Facilities should consider the impact of larval density, population size, and air temperature during black soldier fly mass production as these factors impact overall larval production.

Additive facilitated co-composting of lignocellulosic biomass waste, approach towards minimizing greenhouse gas emissions: An up to date review

Although the composting of lignocellulosic biomass is an emerging waste-to-wealth approach towards organic waste management and circular economy, it still has some environmental loopholes that must be addressed to make it more sustainable and reliable. The significant difficulties encountered when composting lignocellulosic waste biomass are consequently discussed in this study, as well as the advances in science that have been achieved throughout time to handle these problems in a sustainable manner. It discusses an important global concern, the emission of greenhouse gases during the composting process which limits its applicability on a broader scale. Furthermore, it discusses in detail, how different organic minerals and biological additives modify the physiochemical and biological characteristics of compost, aiming at developing eco-friendly compost with minimum odor, greenhouse gases emission and an optimum C/N ratio. It brings novel insights by demonstrating the effect of additives on the microbial enzymes and their pathways involved in the degradation of lignocellulosic biomass. This review also highlights the limitations of the application of additives in composting and suggests possible ways to overcome these limitations in the future for the sustainable and eco-friendly management of agricultural waste. The present review concludes that the use of additives in the co-composting of lignocellulosic biomass can be a viable remedy for the ongoing issues with the management of lignocellulosic waste.

Production of compost from logging residues

The implementation of forest management generates logging residue which can be used in several ways. One of the option is to use of logging residue in the composting process. Therefore, this study determined the possibility of producing compost based on logging residue and the produced fertilizer used to fertilize forest nurseries. Pine chips and sewage sludge were used for carrying out the study. The compost, as well as the leachate produced during composting, were characterized by high NPK content. The leachate collected at the end of the experiment was characterized by nitrogen content of approximately 6500 mg‧dm^-3, phosphorus of approximately 450 mg‧dm^-3, and potassium of approximately 500-700 mg‧dm^-3. In contrast, the compost produced contained approximately 0.57 g‧kg^-1 nitrogen, approximately 0.39 g‧kg^-1 phosphorus, and approximately 0.24 g‧kg^-1 potassium. The disadvantage in terms of the usefulness of the resulting fertilizer in forest nurseries is its pH, which exceeded 9.0.

Heavy metal remediation using chelator-enhanced washing of municipal solid waste compost based on spectroscopic characterization

Due to high metal toxicity, mixed municipal solid waste (MSW) compost is difficult to use. This study detected the presence of heavy metals (Cd, Cu, Pb, Ni, and Zn) in MSW compost through mineralogical analysis using X-ray diffraction (XRD) and performed topographical imaging and elemental mapping using a scanning electron microscope and energy dispersive X-ray analysis (SEM-EDX). Ethylenediaminetetraacetic acid (EDTA), a typical chelator, is tested to remove heavy metals from Indian MSW compost (New Delhi and Mumbai). It deals with two novel aspects, viz., (i) investigating the influence of EDTA-washing conditions, molarity, dosage, MSW compost-sample size, speed, and contact time, on their metal removal efficiencies, and (ii) maximizing the percentage removal of heavy metals by determining the optimal process control process parameters. These parameters were optimized in a batch reactor utilizing Taguchi orthogonal (L₂₅) array. The optimization showed that the removal efficiencies were 96.71%, 47.37%, and 49.94% for Cd, Pb, and Zn in Delhi samples, whereas 45.55%, 79.52%, 59.63%, 82.31%, and 88.40% for Cd, Cu, Pb, Ni, and Zn in Mumbai samples. Results indicate that the removal efficiency of heavy metals was greatly influenced by EDTA-molarity. Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of hydroxyl group, which aids heavy metal chelation. The results reveal the possibility of EDTA to reduce the hazardous properties of MSW compost.

An inclusive outlook on the fate and persistence of pesticides in the environment and integrated eco-technologies for their degradation

Intensive and inefficient exploitation of pesticides through modernized agricultural practices has caused severe pesticide contamination problems to the environment and become a crucial problem over a few decades. Due to their highly toxic and persistent properties, they affect and get accumulated in non-target organisms, including microbes, algae, invertebrates, plants as well as humans, and cause severe issues. Considering pesticide problems as a significant issue, researchers have investigated several approaches to rectify the pesticide contamination problems. Several analyses have provided an extensive discussion on pesticide degradation but using specific technology for specific pesticides. However, in the middle of this time, cleaner techniques are essential for reducing pesticide contamination problems safely and environmentally friendly. As per the research findings, no single research finding provides concrete discussion on cleaner tactics for the remediation of contaminated sites. Therefore, in this review paper, we have critically discussed cleaner options for dealing with pesticide contamination problems as well as their advantages and disadvantages have also been reviewed. As evident from the literature, microbial remediation, phytoremediation, composting, and photocatalytic degradation methods are efficient and sustainable and can be used for treatment at a large scale in engineered systems and in situ. However, more study on the bio-integrated system is required which may be more effective than existing technologies.

Microplastics as an underestimated emerging contaminant in solid organic waste and their biological products: Occurrence, fate and ecological risks

Microplastics (MPs), as an emerging pollutant, have been widely detected in aquatic, terrestrial, and atmospheric ecosystems. Recently, more researchers indicated that solid organic waste is also a crucial repository of MPs and has become a vital pollution source in ecosystems. Although the occurrence and fate of MPs in solid organic waste and the interaction between MPs and biological treatments have been explored, there still needs to be comprehensive summaries. Hence, this study reviewed the occurrence and characteristics of MPs in solid organic waste and organic fertilizers. Meanwhile, this study summarized the influence of MPs on biological treatments (composting and anaerobic digestion) and their degradation characteristics. MPs are abundant in solid organic waste (0-220 ×103 particles/kg) and organic fertilizer (0-30 ×103 particles/kg), PP and PE are the prominent MPs, and fibers and fragments are the main shapes. MPs can affect the carbon and nitrogen conversion during biological treatments and interfere with microbial communities. The MP's characteristics changed after biological treatments, which should further consider their potential ecological risks. This review points out the existing problems of MPs in organic waste recycling and provides directions for their treatment in the future.

Revisiting the oldest manure of India, Kunapajala: Assessment of its animal waste recycling potential as a source of plant biostimulant

India's oldest documented manure, most commonly referred to as Kunapajala, has a long history of over 1,000 years in crop cultivation. Kunapajala is primarily an in-situ decomposition technology of animal waste and can potentially provide an eco-friendly pipeline for recycling bio-waste into essential plant nutrients. This traditional animal manure, in addition, also contains dairy excreta (e.g., feces and urine), dairy products (e.g., milk and ghee), natural resources (e.g., honey), broken seeds or grains, and their non-edible by-product waste. Here, we aimed to assess the waste recycling and plant biostimulant potential of Kunapajala prepared from livestock (e.g., Black Bengal goats) or fish (e.g., Bombay duck) post-processed wastes over different decomposition periods, e.g., (0, 30, 60, and 90-days). In this study, an in-situ quantification of livestock- (lKPJ) and fish-based Kunapajala (fKPJ) reveals a dynamic landscape of essential plant primary nutrients, e.g., (0.70 > NH4-N < 3.40 g•L−1), (100.00 > P2O5 < 620.00 mg•L−1), and (175.00 > K2O < 340.00 mg•L−1), including other physico-chemical attributes of Kunapajala. Using correlation statistics, we find that the plant-available nutrient content of Kunapajala depicts a significant (p < 0.0001) transformation over decomposition along with microbial dynamics, abundance, and diversities, delineating a microbial interface to animal waste decomposition and plant growth promotion. Importantly, this study also reports the indole 3-acetic acid (IAA) content (40.00 > IAA < 135.00 mg•L−1) in Kunapajala. Furthermore, the bacterial screening based on plant growth-promoting traits and their functional analyses elucidate the mechanism of the plant biostimulant potential of Kunapajala. This assay finally reports two best-performing plant growth-promoting bacteria (e.g., Pseudomonas chlororaphis and Bacillus subtilis) by the 16S ribotyping method. In support, in-planta experiments have demonstrated, in detail, the bio-stimulative effects of Kunapajala, including these two bacterial isolates alone or in combination, on seed germination, root-shoot length, and other important agronomic, physio-biochemical traits in rice. Together, our findings establish that Kunapajala can be recommended as a source of plant biostimulant to improve crop quality traits in rice. Overall, this work highlights Kunapajala, for the first time, as a promising low-cost microbial technology that can serve a dual function of animal waste recycling and plant nutrient recovery to promote sustainable intensification in agroecosystems.

Incorporation of Substrates and Inoculums as Operational Strategies to Promote Lignocellulose Degradation in Composting of Green Waste—A Pilot-Scale Study

Composting is a sustainable alternative for green waste (GW) valorization contributing to the circular bioeconomy. However, the processing time must be reduced and the end-product quality must be improved. This study determined the effect of the incorporation of processed food waste (PFW), unprocessed food (UPFW), sawdust (SW), phosphate rock (PR) and a specific bacterial inoculum on GW-composting process parameters and product quality. Three treatments were evaluated in 120 kg piles: (i) TA: (GW + UPFW + PFW + inoculum), (ii) TB (GW + UPFW + PFW), and (iii) TC (GW). An inoculum of Bacillus sp. and Paenibacillus sp. was incorporated in the cooling phase for TA. On the other hand, the effect of the inoculum at the laboratory scale (20 kg reactors) was compared with that found at the pilot scale (120 kg piles). The incorporation of FW, SW, PR and the inoculum increased the amount of lignocellulose biodegradation (TA: 29.1%; TB: 22.7%; TC: 18.2%), which allowed for a reduction of up to 14 days of processing time. The product obtained for TA had a similar quality to the other two treatments, although a lower phytotoxicity was determined according to the germination index (TA: 95%; TB: 85%; and TC: 83%). The final product of TA showed the best agricultural characteristics with pH 8.3, TOC of 24.8%, TN of 1.32%, and GI of 98.8%. Finally, the scaling effect with the bacterial inoculum was shown to affect parameters such as the TOC, TN, GI, and, to a lesser extent, temperature and pH. The results obtained in this paper highlight the importance of optimizing the composting of GW, specifically with the use of co-substrates and specific inocula, which can be of interest for composting materials with a high content of lignocellulose such as GW.

A review on biological methodologies in municipal solid waste management and landfilling: Resource and energy recovery

Rapid industrialization and urbanization growth combined with increased population has aggravated the issue of municipal solid waste generation. MSW has been accounted for contributing tremendously to the improvement of sustainable sources and safe environment. Biological processing of MSW followed by biogas and biomethane generation is one of the innumerable sustainable energy source choices. In the treatment of MSW, biological treatment has some attractive benefits such as reduced volume in the waste material, adjustment of the waste, economic aspects, obliteration of microorganisms in the waste material, and creation of biogas for energy use. In the anaerobic process the utilizable product is energy recovery. The current review discusses about the system for approaching conversion of MSW to energy and waste derived circular bioeconomy to address the zero waste society and sustainable development goals. Biological treatment process adopted with aerobic and anaerobic processes. In the aerobic process the utilizable product is compost. These techniques are used to convert MSW into a reasonable hotspot for resource and energy recovery that produces biogas, biofuel and bioelectricity and different results in without risk and harmless to the ecosystem. This review examines the suitability of biological treatment technologies for energy production, giving modern data about it. It likewise covers difficulties and points of view in this field of exploration.

Effects of Functionalized Materials and Bacterial Metabolites on Quality Indicators in Composts

The addition of functionalized materials (biochar, zeolite, and diatomite) and lyophilized metabolic products of Pseudomonas sp. and Bacillus subtilis to composted biomass may bring many technological and environmental benefits. In this study, we verify the effects of biochar, zeolite Na-P1 (Na6Si10Al6O32·12 H2O), diatomite (SiO2_nH2O), and bacterial metabolites on the composting of biomass prepared from poultry litter, corn straw, grass, leonardite, and brown coal. The experimental design included the following treatments: C-biomass without the addition of functionalized materials and bacterial metabolites, CB-biomass with the addition of biochar, CBM-biomass with the addition of biochar and bacterial metabolites, CZ-biomass with the addition of zeolite, CZM-biomass with the addition of zeolite and bacterial metabolites, CD-biomass with the addition of diatomite, and CDM-biomass with the addition of diatomite and bacterial metabolites. Composts were analyzed for enzymatic and respiratory activities, mobility of heavy metals, and the presence of parasites. The results of this study revealed that, among the analyzed functionalized materials, the addition of diatomite to the composted biomass (CD and CDM) resulted in the most effective immobilization of Cd, Zn, Pb, and Cu. Zinc immobilization factors (IFHM) for diatomite-amended composts averaged 30%. For copper, each functionalized material was found to enhance mobilization of the element in bioavailable forms; similar observations were made for lead, except for the compost to which biochar and bacterial metabolites were added (CBM). The determined values of biochemical indicators proved the different effects of the applied functionalized materials and bacterial metabolites on the microbial communities colonizing individual composts. The dehydrogenase activity (DhA) was lower in all combinations as compared with the control, indicating an intensification of the rate of processes in the studied composts. The highest basal respiration (BR) and substrate-induced respiration (SIR) activities were determined in composts with the addition of bacterial metabolites (CBM, CZM, and CDM). The addition of functionalized materials completely inactivated Eimeria sp. in all combinations. In the case of Capillaria sp., complete inactivation was recorded for the combination with zeolite as well as biochar and diatomite without bacterial metabolites (CB, CZ, and CD).

Composting effect and antibiotic removal under a new temperature control strategy

The main objective of this study was to investigate the feasibility of a new temperature control strategy in the co-composting process to accelerate operation cycle and remove antibiotics from mixed organic wastes. The evaluation of the composting process showed that composting with temperature control (TC) was completed within 14 days. The final compost of TC exhibited a 10% higher degradation of organic matters, more humus formation and 11.25% lower heavy metals concentration than conventional composting (CC), which fully met the Chinese National Agricultural Organic Fertilizer Standard requirements. The degradation extent and kinetic of macrolides, tetracyclines, sulfonamides and fluoroquinolones showed that the removal efficiency of total antibiotics in TC was 23.58% higher than CC, with less half-life, which was significantly correlated with higher temperature. Particularly, the highest removal was observed for sulfonamides (87.45%) in TC, the half-life of which was reduced by 75.95% compared with CC. The higher degradation rate was attributed to enhanced decomposition of unstable antibiotics and degrading activity of microbes at high temperature. The microbiological analysis showed that the external heating led to a distinct composition and succession of bacterial community in TC. Firmicutes, Proteobacteria, Actinobacteriota and Bacteroidota were dominant and the emergence of Patescibacteria and Chloroflexi at cooling period in TC proved that the later composting environment was in an oligotrophic state. Current research provided a promising rapid composting approach for high-quality fertilizer production and antibiotic management in organic waste disposal.

Research progress on influencing factors on compost maturity and cyanobacteria toxin degradation during aerobic cyanobacteria composting: a review

Cyanobacterial bloom is by far one of the most common water quality hazards. As cyanobacteria are rich in nitrogen, phosphorus, and other organic matter, the potential for beneficial use of cyanobacteria is promising. Aerobic composting is currently a hot topic of research in cyanobacteria treatment, which can effectively achieve reduction, recycling, and removal of the harmful impact of cyanobacteria. In this review, the characteristics of cyanobacteria in aerobic composting processes, the effects of physical, chemical, and biological factors on the composting process, and the degradation of microcystic toxins were systematically discussed and summarized. This review epitomizes the large quantities of research data collected by many scholars around the world to address the characteristics of "one low and five highs" in the aerobic cyanobacterial composting process. The composting techniques developed are effective and easy to adopt in the real world, such as adjusting the substrate C/N ratio and moisture content and use of chemical and biological additives to achieve reduction, recycling, and detoxication of the cyanobacterial wastes. The aim of this comprehensive review is to provide theoretical guidance and reference for further development and application of aerobic cyanobacteria composting technology.

Biodegradable active materials containing phenolic acids for food packaging applications

The development of new materials for food packaging applications is necessary to reduce the excessive use of disposable plastics and their environmental impact. Biodegradable polymers represent an alternative means of mitigating the problem. To add value to biodegradable materials and to enhance food preservation, the incorporation of active compounds into the polymer matrix is an affordable strategy. Phenolic acids are plant metabolites that can be found in multiple plant extracts and exhibit antioxidant and antimicrobial properties. Compared with other natural active compounds, such as essential oils, phenolic acids do not present a high sensorial impact while exhibiting similar minimal inhibitory concentrations against different bacteria. This study summarizes and discusses recent studies about the potential of both phenolic acids/plant extracts and biodegradable polymers as active food packaging materials, their properties, interactions, and the factors that could affect their antimicrobial efficiency. The molecular structure of phenolic acids greatly affects their potential antioxidant and antimicrobial capacity, as well as their specific interactions with polymer matrices and food substrates. These interactions, in turn, can lead to plasticizing or cross-linking effects. In the present study, the antioxidant and antimicrobial properties of different biodegradable films with phenolic acids have been described, as well as the main factors affecting the active properties of these films as useful materials for active packaging development. More studies applying these active materials in real foods are required.

In Silico Identification of Potential Sites for a Plastic-Degrading Enzyme by a Reverse Screening through the Protein Sequence Space and Molecular Dynamics Simulations

The accumulation of polyethylene terephthalate (PET) seriously harms the environment because of its high resistance to degradation. The recent discovery of the bacteria-secreted biodegradation enzyme, PETase, sheds light on PET recycling; however, the degradation efficiency is far from practical use. Here, in silico alanine scanning mutagenesis (ASM) and site-saturation mutagenesis (SSM) were employed to construct the protein sequence space from binding energy of the PETase–PET interaction to identify the number and position of mutation sites and their appropriate side-chain properties that could improve the PETase–PET interaction. The binding mechanisms of the potential PETase variant were investigated through atomistic molecular dynamics simulations. The results show that up to two mutation sites of PETase are preferable for use in protein engineering to enhance the PETase activity, and the proper side chain property depends on the mutation sites. The predicted variants agree well with prior experimental studies. Particularly, the PETase variants with S238C or Q119F could be a potential candidate for improving PETase. Our combination of in silico ASM and SSM could serve as an alternative protocol for protein engineering because of its simplicity and reliability. In addition, our findings could lead to PETase improvement, offering an important contribution towards a sustainable future.

Integrating 16S rRNA amplicon metagenomics and selective culture for developing thermophilic bacterial inoculants to enhance manure composting

Composting is an important method for treating and recycling organic waste, and the use of microbial inoculants can increase the efficiency of composting. Herein, we illustrate an approach that integrate 16S rRNA amplicon metagenomics and selective culture of thermophilic bacteria for the development of inoculants to improve manure composting. The 16S rRNA amplicon sequencing analysis revealed that Firmicutes and Actinobacteria were dominant in the composting mixture, and that different microbial hubs succeeded during the thermophilic stage. All isolated thermophilic bacteria were affiliated with the order Bacillales, such as Geobacillus, Bacillus, and Aeribacillus. These isolated thermophilic bacteria were grouped into 11 phylotypes, which shared ＞99% sequence identity to 0.15% to 5.32% of 16S rRNA reads by the amplicon sequencing. Three of these phylotypes transiently enriched during the thermophilic stage. Six thermophilic bacteria were selected from the three phylotypes to obtain seven microbial inoculants. Five out of seven of the microbial inoculants enhanced the thermophilic stage of composting by 16.9% to 52.2%. Three-dimensional excitation emission matrix analysis further revealed that two inoculants (Thermoactinomyces intermedius and Ureibacillus thermophilus) stimulated humification. Additionally, the 16S rRNA amplicon sequencing analysis revealed that inoculation with thermophilic bacteria enhanced the succession of the microbial community during composting. In conclusion, 16S rRNA amplicon metagenomics is a useful tool for the development of microbial inoculants to enhance manure composting.

Indigenous cellulolytic aerobic and facultative anaerobic bacterial community enhanced the composting of rice straw and chicken manure with biochar addition

Microbial degradation of organic matters is crucial during the composting process. In this study, the enhancement of the composting of rice straw and chicken manure with biochar was evaluated by investigating the indigenous cellulolytic bacterial community structure during the composting process. Compared with control treatment, composting with biochar recorded higher temperature (74 °C), longer thermophilic phase (> 50 °C for 18 days) and reduced carbon (19%) with considerable micro- and macronutrients content. The bacterial community succession showed that composting with biochar was dominated by the cellulolytic Thermobifida and Nocardiopsis genera, which play an important role in lignocellulose degradation. Twenty-three cellulolytic bacterial strains were successfully isolated at different phases of the composting with biochar. The 16S rRNA gene sequencing similarity showed that they were related to Bacilluslicheniformis, Bacillussubtilis,Bacillusaerius, and Bacillushaynesii, which were known as cellulolytic bacteria and generally involved in lignocellulose degradation. Of these isolated bacteria, Bacilluslicheniformis, a facultative anaerobe, was the major bacterial strain isolated and demonstrated higher cellulase activities. The increase in temperature and reduction of carbon during the composting with biochar in this study can thus be attributed to the existence of these cellulolytic bacteria identified.

Toward a Cleaner and more Sustainable World: A Framework to Develop and Improve Waste Management through Organizations, Governments and Academia

Waste production is expected to reach 3.40 billion tons annually in 2050. To decrease its negative impacts on the environment generated by human activities, waste management (WM) aims to increase the products life cycle and reduce the use of energy and space. Thus, this work aims to propose a framework with actions to develop and improve WM in the Triple Helix (TH) sectors: organizations, governments, and academia. The framework was developed based on the benchmarking of the technical-scientific scenario and the opportunities and challenges of WM added to the authors' experiences. This study was conducted using a combined method of the literature review and content analysis of articles present in the Scopus database, patents identified in the Orbit database, and governmental actions. As a result, 32 actions have been proposed through the framework, distributed among the TH sectors. The countries analyzed were China, India, and the United States, which highlighted because of the h-index and number of patents published. The main scientific contribution of this work is to add empirical elements coming directly from public and private institutions to the theory about WM, forming a block of knowledge with characteristics closer to reality. The major applied contribution of this work is the proposition of actions to the TH sectors, enabling the development of solutions and technologies to improve WM.

Qualitative assessment of compost engendered from municipal solid waste and green waste by indexing method

The present study aims at quantification of the quality of three varieties of composts made from municipal solid waste, green waste and combined waste by critically evaluating their physicochemical attributes, effect on soil fertility and metal pollution risk. Each waste type was treated with effective micro-organisms to compare the compost quality using Quality Control Indices. The effect of microbial consortia on the wastes was prominent resulting in decreased pH levels and increased electrical conductivity. C/N ratio ranged between 14-24 for waste composts without microbial treatment, and 8-11 for microbial treated wastes. The fertility parameter was observed to be more in microbial treated waste composts. Also, heavy metals concentration in waste compost without effective microbial treatment was higher than the types given EM. Based on the fertility and clean indices, the treated and untreated municipal solid waste and combined waste compost belonged to class RU-1 and class D, respectively. Moreover, compost prepared from treated and untreated green waste belonged to classes B and C respectively. In general, the prepared CW and GW composts have medium to high fertilizing potential and are fit for domestic as well as commercial use. However, MSW compost is not fit for agricultural purposes as it didn't improve soil fertility to a greater extent but can be used as a soil conditioner in limited quantity as it can cause metal toxicity. For this reason, proper segregation of inputs at the start of a composting process is necessary to improve its quality before being put to agricultural use as any unbalanced or unchecked content of mixed waste will affect the overall compost quality.Implications: Significance of the work: The research dealt with different combinations of segregated wastes to analyze the best fit solid waste compost. Experiments were conducted on the actual landfill site area to simulate the conditions for the process. The manuscript provides evidence and other facts advocating the use of composting for waste management and ultimately reducing pollution caused by landfilling. It ought to cause a multiplier effect if the same is to be followed in other parts of the world, and thus working our way toward getting the Smart city project to fruition. The results of the study exhibit the differences in physiochemical nature of various types of composts. A treatment of microbial consortium with restrictions enabled a conducive atmosphere in the colonies to thrive faster and initiate the process of decomposition. We observed that treated samples converted faster into compost as compared to non-treated samples. We also observed the effect of treatment on fertility parameters of prepared compost samples. In general, it was found that the organic carbon and C/N ratio declined while the total nitrogen and total potassium was observed to increase with very little to no change in phosphorous content, with the inoculation of beneficial micro-organisms throughout the composting course. A reduction in the heavy metal levels was observed in samples treated with active micro-organisms. The compost classification into A, B, C, and D classes represents the quality of compost and further use in agricultural land on commercial levels. The quality index values were determined highest for green waste compost (GWC). The municipal solid waste compost (MSWC) exhibited lowest index values. Therefore, based on the quality index values, the utilization of GWC will aid in reutilizing the green waste and in boosting soil fertility and reduce the waste quantity generation rates. It's also necessary to make compost making widespread among the farmers for a sustainable environment. The GWC has been considered as a sustainable option of waste management, being economically and ecologically viable.

Biohumus “Sis” for the ecologically pure agricultural production

This study aimed to investigate the influence of the microbial biohumus obtained from organic non-toxic wastes on the yield of three varieties of peppers, identification of the effect of biohumus on soil physicochemical parameters, to determine the ecological significance and economic feasibility of biohumus application. The photosynthetic activity of plants and accumulation of ascorbic acid in the tissues of peppers were investigated. The experiments in the vegetation cabin condition have been carried out according to the following variants: 1. Control, 2. Biohumus, 3. N60P60K60, 4. Biohumus + N60P60K60. The yield of a variety of Jermatnayin hska pepper in the vegetation cabin conditions in the Biohumus (237 c/ ha) variant was lower than in the “Biohumus + N60P60K60” variant and was higher from “N60P60K60” and “Control” variants (277c/ha, 229 c/ha, and 191c/ha respectively). The yield of a variety of Arajnek pepper in the Biohumus (286 c/ha) variant was lower than in the “Biohumus + N60P60K60” variant and was higher “N60P60K60” and “Control” variants (320c/ha, 265c/ha, and 228c/ha respectively). The yield of a variety of Loshtak pepper in the “Biohumus” (335.7 c/ha) variant was lower than in the “Biohumus + N60P60K60” variant and was higher in “N60P60K60” and “Control” variants (391.9c/ha, 314c/ha, and 239.8c/ha respectively).

A review on integrated approaches for municipal solid waste for environmental and economical relevance: Monitoring tools, technologies, and strategic innovations

Rapid population growth, combined with increased industrialization, has exacerbated the issue of solid waste management. Poor management of municipal solid waste (MSW) not only has detrimental environmental consequences but also puts public health at risk and introduces several other socioeconomic problems. Many developing countries are grappling with the problem of safe disposing of large amounts of produced municipal solid waste. Unmanaged municipal solid waste pollutes the environment, so its use as a potential renewable energy source would aid in meeting both increased energy needs and waste management. This review investigates emerging strategies and monitoring tools for municipal solid waste management. Waste monitoring using high-end technologies and energy recovery from MSW has been discussed. It comprehensively covers environmental and economic relevance of waste management technologies based on innovations achieved through the integration of approaches.

Remediation of soils and sediments polluted with polycyclic aromatic hydrocarbons: To immobilize, mobilize, or degrade?

Polycyclic aromatic hydrocarbons (PAHs) are generated due to incomplete burning of organic substances. Use of fossil fuels is the primary anthropogenic cause of PAHs emission in natural settings. Although several PAH compounds exist in the natural environmental setting, only 16 of these compounds are considered priority pollutants. PAHs imposes several health impacts on humans and other living organisms due to their carcinogenic, mutagenic, or teratogenic properties. The specific characteristics of PAHs, such as their high hydrophobicity and low water solubility, influence their active adsorption onto soils and sediments, affecting their bioavailability and subsequent degradation. Therefore, this review first discusses various sources of PAHs, including source identification techniques, bioavailability, and interactions of PAHs with soils and sediments. Then this review addresses the remediation technologies adopted so far of PAHs in soils and sediments using immobilization techniques (capping, stabilization, dredging, and excavation), mobilization techniques (thermal desorption, washing, electrokinetics, and surfactant assisted), and biological degradation techniques. The pros and cons of each technology are discussed. A detailed systematic compilation of eco-friendly approaches used to degrade PAHs, such as phytoremediation, microbial remediation, and emerging hybrid or integrated technologies are reviewed along with case studies and provided prospects for future research.

Rapid-in-house composting of organic solid wastes with fly ash supplementation: Performance evaluation at thermophilic exposures

The present work was envisaged to design, fabricate, and evaluate the performance of rapid in-house composters (RICs) for composting of organic wastes comprising kitchen waste and brown waste with fly ash supplementation in the fixed combination. The prime objective of the present study was to evaluate the ideal operating temperature suitable for rapid action of pro-composting microorganisms in indigenously developed RIC. Four identical RICs were exposed to temperatures of 40 ℃, 45  ℃, 55 ℃, and 65 ℃, respectively. The factors governing the composting process were regulated through specifically designed components. Qualitative parameters like pH, moisture content (MC), C/N ratio and heavy metals were analyzed at regular intervals. Principal component analysis was used to evaluate the relationship between the obtained results. The RIC with 55 ℃ temperature exposure, 70% MC for nine days and aeration at 4 L per minute exhibited the best results with 15.13C/N ratios of compost.

Potential of windrow food and green waste composting in Tunisia

Solid waste management and disposal is one of the most significant challenges facing urban communities around the world. There is a wide range of alternative waste management options and strategies available for dealing with the notable increase in the waste stream. Composting is one of the most viable and efficient waste treatment options in terms of the reduction in the negative effects from the application of organic waste to soil. The experimental research aimed to examine the potential of producing compost from different organic waste streams in Tunisia. Two experimental windrow piles made from cooked and uncooked food and garden wastes were initiated and temporally monitored. The composting process was controlled in terms of temperature and moisture. Sampling was carried out over the period of the composting process. All of the collected samples were analyzed in terms of their physical, chemical, and biological properties; pH, C:N ratio, nitrification index (NI), microbiological tests, respiration activity (AT4), and heavy metal content. The quality of the final product was determined and compared with Tunisian and German standards. The findings demonstrated a significant reduction in the initial C:N ratio to about 15 by the end of the process. Additionally, the results showed that the compost produced appeared to be stable and was deemed to be class V finished compost; the NI was found to be around 1, while the AT4 was estimated to be lower than 6 mg O2/g TS. Regarding the heavy metal content, the final products were characterized as having a lower concentration than those values set by Tunisian and German standards.

Organic waste amendments for restoration of physicochemical and biological productivity of mine spoil dump for sustainable development

Rehabilitation of degraded lands due to mining and other activities requires rebuilding of the appropriate soil structure and microbial integrity. Organic wastes, in particular plant-based materials, play a vital role in restoration of degraded land when used as amendments for topsoil integrated with microbe-assisted phytoremediation. In this present study, a biotechnological approach using the combination of organic waste amendments, i.e., ETP (effluent treatment plant), sludge from sugarcane and paper industry, and the press mud respectively along with microbial and fungal inoculum isolated from the soil rhizosphere have been applied to study the influence on fertility and productivity of mine spoil from manganese and coal dumps. The organic amendments applied as 100-ton ha^-1 and application of biofertilizers boosted the survival of plants such as Tectona grandis (Teak), Dalbergia sisso (North Indian rosewood), Phyllanthus emblica (Indian gooseberry), Gmelina arborea (Gamhar), and Acacia auriculiformis (Earpod wattle) from 80 to 100% with robust growth and development during the short span of 25 years. The physicochemical attributes of soil and the microbial count also increased significantly. The pH of mine soil dumps slightly shifted toward alkaline conditions (7.4 to 7.8) whereas bulk density, porosity, and the water holding capacity were greatly improved. Other than this, the nutrient status of mine dump soil and the plants such as available nitrogen, phosphorus, potassium and the organic carbon content in soil were improvised to a greater extent simultaneously decreasing the available manganese concentration. The findings of the study assure a better land reclamation and restoration approach.

The Effect of Two Dietary Protein Sources on Water Quality and the Aquatic Microbial Communities in Marron (Cherax cainii) Culture

Feeding freshwater crayfish species with different diets not only affects the water quality but also induces the abundance of various microbial communities in their digestive tracts. In this context, very limited research has been undertaken to understand the impacts of various protein incorporated aqua-diets on the characteristics of water and its microbial communities. In this study, we have critically analysed the water quality parameters including pH, dissolved oxygen, nitrate, nitrite, ammonia and phosphorus, as well as bacterial communities under marron (Cherax cainii) aquaculture, fed fishmeal (FM) and poultry by-product meal (PBM)-based diets for 60 days. The results unveiled that over the time, feeding has significant impacts on organic waste accumulation, especially ammonia, nitrate, nitrite and phosphate, while no effects were observed on pH and dissolved oxygen. Analysis of 16S rRNA sequence data of water sample indicated significant (P < 0.05) shift of microbial abundance in post-fed FM and PBM water with the evidence of microbial transmission from the gut of marron. Post-fed marron resulted in a significant correlation of Hafnia, Enterobacter, Candidatus Bacilloplasma and Aquitella with the quality and microbial population of water. The results of this study generated valuable knowledge database of microbes-water relationship for better health management practices and production of marron aquaculture fed with FM and PBM diets in under restricted feeding regime with the feeding ratios provided.

Isolation and Characterization of Beneficial Bacteria from Food Process Wastes

Significant quantities of food waste are accumulated globally on an annual basis, with approximately one-third of the food produced (equivalent to 1.3 billion tons of food) being wasted each year. A potential food waste recycling application is its utilization as a soil conditioner or fertilizer, whereby it increases the soil organic content and microbial biomass. This study evaluated the effectiveness of food waste as a microbial resource by analyzing the microbial community composition and isolating plant growth-promoting bacteria (PGPB) in food waste obtained from various sources. High-throughput sequencing identified 393 bacterial operational taxonomic units in the food process waste (FPW) samples. Moreover, the results showed that Firmicutes was abundant in the waste samples, followed by Bacteroidetes and Proteobacteria. A total of 92 bacteria were isolated from FPW. Moreover, the cultivable strains isolated from FPW belonged to the genus Bacillus, followed by Streptomyces and Proteus. Six isolated bacteria exhibited beneficial traits, including indole acetic acid production, antifungal resistance and extracellular lysis. FPW is a valuable microbial resource for isolation of PGPB, and its use as a fertilizer may enable a reduction in chemical fertilizer usage, thereby mitigating the corresponding adverse environmental impacts on sustainable crop development.

Assessment of municipal solid waste management system in Lae City, Papua New Guinea in the context of sustainable development

ABSTRACT

Lae City (LC) of Morobe Province is the second-largest city in Papua New Guinea. Due to the abundant natural resources it inherits, the resultant urbanization has led to an influx of the human population. This increase in population as a result of industrialization has led to increased municipal solid waste (MSW) accumulation. To address this exigent issue, which affects the nation's carbon footprint, it is imperative to review socio-economic and geographic factors to establish a feasible approach for managing MSW efficiently and sustainably. In the quest to achieve the same, the present assessment focuses on the 3 core waste management hierarchy systems to support sustainable development for LC by reviewing existing opportunities and challenges associated with the current MSW management system and the associated policies. The result shows that as a sustainable approach to MSW management of LC, a zero-waste campaign for resource recovery engaging all stakeholders can be implemented since the organic content of MSW generated in LC is as high as 70%. Moreover, the dumping of MSW at the dedicated dumpsite site can be minimized if policies are strengthened and the proposed waste avoidance pathway is implemented strictly. In addition to this, to avoid the contamination of groundwater and recovery of methane, the use of the Fukuoka approach in the existing landfills has been suggested to capture leachate without any huge expenditure.

Reducing odor emissions from feces aerobic composting: additives

Aerobic composting is a reliable technology for treating human and animal feces, and converting them into resources. Odor emissions in compost (mainly NH₃ and VSCs) not only cause serious environmental problems, but also cause element loss and reduce compost quality. This review introduces recent progresses on odor mitigation in feces composting. The mechanism of odor generation, and the path of element transfer and transformation are clarified. Several strategies, mainly additives for reducing odors proven effective in the literature are proposed. The characteristics of these methods are compared, and their respective limitations are analyzed. The mechanism and characteristics of different additives are different, and the composting plant needs to be chosen according to the actual situation. The application of adsorbent and biological additives has a broad prospect in feces composting, but the existing research is not enough. In the end, some future research topics are highlighted, and further research is needed to improve odor mitigation and element retention in feces compost.

Aerobic composting is a reliable technology for treating human and animal feces, and converting them into resources. The addition of additives can reduce the production of odor during the composting process.

Optimization of Bokashi-Composting Process Using Effective Microorganisms-1 in Smart Composting Bin

Malaysians generate 15,000 tons of food waste per day and dispose of it in the landfill, contributing to greenhouse gas emissions. As a solution for the stated problem, this research aims to produce an excellent quality bokashi compost from household organic waste using a smart composting bin. The bokashi composting method is conducted, whereby banana peels are composted with three types of bokashi brans prepared using 12, 22, and 32 mL of EM-1 mother cultured. During the 14 days composting process, the smart composting bin collected the temperature, air humidity, and moisture content produced by the bokashi-composting process. With the ATmega328 microcontroller, these data were uploaded and synchronized to Google Sheet via WIFI. After the bokashi-composting process was completed, three of each bokashi compost and a control sample were buried in separate black soil for three weeks to determine each compost’s effectiveness. NPK values and the C/N ratio were analyzed on the soil compost. From the research, 12 mL of EM-1 shows the most effective ratio to the bokashi composting, as it resulted in a faster decomposition rate and has an optimum C/N ratio. Bokashi composting can help to reduce household food wastes. An optimum amount of the EM-1 used during the bokashi-composting process will produce good quality soil without contributing to environmental issues.

Evaluation of Inoculated Waste Biological Stabilization Degree by Olfactometric Methods

As a result of compounds’ transformation in the waste biostabilization phases, there is an increase in odor nuisance and health problems among people exposed to odorants. Linking the odor concentration to the degree of waste biostabilization may be an important tool for the assessment of individual technological variants of biostabilization. The study aimed to link the odor emissions to the biostabilization degree in individual process variants that differed in the inoculum. The tests were carried out on inoculated windrows on the waste mechanical-bological treatment open site. Odor concentrations were measured during the entire seven-week process of biostabilization (weeks 1–7) and compared with kinetics parameters of organic compounds’ decomposition. The olfactometric tests showed the necessity of using the preparation to reduce the value of odor concentration. Research proved that the decrease of odor concentration values could be useful to indicate the particular phases of biostabilization. Also, the proposed method provides an opportunity to optimize the process concerning the function related to the low degree of odor nuisance of the technologies, including selection of environmentally safe inoculum. This issue has application values that may result in the implementation of new control systems for waste stabilization bioreactors and the evaluation of applied technological solutions.

Livestock Manure Type Affects Microbial Community Composition and Assembly During Composting

Composting is an environmentally friendly way to turn plant and animal wastes into organic fertilizers. However, it is unclear to what extent the source of animal waste products (such as manure) affects the physicochemical and microbiological properties of compost. Here, we experimentally tested how the type of livestock manure of herbivores (sheep and cattle) and omnivores (pig and chicken) influences the bacterial and fungal communities and physicochemical properties of compost. Higher pH, NO₃-N, Total carbon (TC) content and C/N were found in sheep and cattle manure composts, while higher EC, NH₄-N, Total nitrogen (TN) and total phosphorus (TP) content were measured in pig and chicken manure composts. Paired clustering between herbivore and omnivore manure compost metataxonomy composition was also observed at both initial and final phases of composting. Despite this clear clustering, all communities changed drastically during the composting leading to reduced bacterial and fungal diversity and large shifts in community composition and species dominance. While Proteobacteria and Chloroflexi were the major phyla in sheep and cattle manure composts, Firmicutes dominated in pig and chicken manure composts. Together, our results indicate that feeding habits of livestock can determine the biochemical and biological properties of manures, having predictable effects on microbial community composition and assembly during composting. Manure metataxonomy profiles could thus potentially be used to steer and manage composting processes.

Cleaner production of agriculturally valuable benignant materials from industry generated bio-wastes: A review

Bio-wastes from different agro-based industries are increasing at a rapid rate with the growing human population's demand for the products. The industries procure raw materials largely from agriculture, finish it with the required major product, and produce huge bio-wastes which are mostly disposed unscientifically. This creates serious environmental problems and loss of resources and nutrients. Traditional bio-wastes disposal possess several demerits which again return with negative impact over the eco-system. Anaerobic digestion, composting, co-composting, and vermicomposting are now-a-days given importance due to the improved and modified methods with enhanced transformation of bio-wastes into suitable soil amendments. The advanced and modified methods like biochar assisted composting and vermicomposting is highlighted with the updated knowledge in the field. Hence, the present study has been carried to compile the effective and efficient methods of utilizing industry generated bio-wastes for circularity between agriculture - industrial sectors to promote sustainability.

Centrality of cattle solid wastes in vermicomposting technology - A cleaner resource recovery and biowaste recycling option for agricultural and environmental sustainability

The current review reports the importance and significance of cattle solid waste in vermicomposting technology concerning biowaste pollution in the environment. Needy increasing population evokes livestock production resulting in the massive generation of livestock wastes, especially cattle dung. Improper disposal and handling of biowastes originating from agriculture, industries, forests, rural and urban areas lead to nutrient loss, environmental pollution and health risks. Among the organic waste disposal methods available, vermicomposting is regarded as an environmentally friendly technology for bioconversion of agricultural, industrial, rural and urban generated organic solid wastes which are serving as reservoirs of environmental pollution. In vermicomposting of organic wastes, cattle dung plays a central role in mineralization, nutrient recovery, earthworm and microbial activity leading to vermifertilizer production. Even though the vermicomposting studies use cattle dung invariably as an amendment material, its importance has not been reviewed to highlight its central role. Hence, the present review mainly emphasizes the key role played by cattle dung in vermicomposting. Vermiconversion of cattle dung alone and in combination with other biowaste materials of environmental concern, mechanisms involved and benefits of vermicompost in sustainable agriculture are the major objectives addressed in the present review. The analysis reveals that cattle dung is indispensable amendment material for vermicomposting technology to ensure agricultural and environmental sustainability by reducing pollution risks associated with biowastes on one hand, and nutrient-rich benign vermifertilizer production on the other hand.

The role of Serendipita indica and Lactobacilli mixtures on mitigating mycotoxins and heavy metals' risks of contaminated sewage sludge and its composts

Accumulation of the Municipal Sewage Sludge (MSS) is considered as one of the most harmful renewable ecological and human health problems. MSS is a renewable resource that could be used as a soil organic amendment. This study aims to reduce the Heavy Metals (HMs) from the sludge content and sludge compost. Furthermore, this study is considered the first to assess the mycotoxins content in sludge and sludge compost via a new biological treatment using the fungus Serendipita indica or a mixture of lactic acid bacteria, thus providing safer nutrients for the soil amendment for a longer time and preserving human health. The HMs and mycotoxins were determined. The results exhibited that the biotic remediation of bio-solid waste and sewage sludge compost succeeded; a new bio-treated compost with a very low content of heavy metals and almost mycotoxins-free contents was availed. Also, the results indicated that the Lactobacilli mixture realized the best results in reducing heavy metals contents and mycotoxins. Afterward, S. indica. biotic remediation of bio-solid waste and sewage sludge compost minimized the health risk hazards affecting the human food chain, allowing for the different uses of sludge to be safer for the environment.