Effects of biochar types on seed germination, growth, chlorophyll contents, grain yield, sodium, and potassium uptake by wheat (Triticum aestivum L.) under salt stress.

Soil salinity is a significant challenge in agriculture, particularly in arid and semi-arid regions such as Pakistan, leading to soil degradation and reduced crop yields. The present study assessed the impact of different salinity levels (0, 25, and 50 mmol NaCl) and biochar treatments (control, wheat-straw biochar, rice-husk biochar, and sawdust biochar applied @ 1% w/w) on the germination and growth performance of wheat. Two experiments: a germination study and a pot experiment (grown up to maturity), were performed. The results showed that NaCl-stress negatively impacted the germination parameters, grain, and straw yield, and agronomic and soil parameters. Biochar treatments restored these parameters compared to control (no biochar), but the effects were inconsistent across NaCl levels. Among the different biochars, wheat-straw biochar performed better than rice-husk and sawdust-derived biochar regarding germination and agronomic parameters. Biochar application notably increased soil pHs and electrical conductivity (ECe). Imposing NaCl stress reduced K concentrations in the wheat shoot and grains with concomitant higher Na concentrations in both parts. Parameters like foliar chlorophyll content (a, b, and total), stomatal and sub-stomatal conductance, and transpiration rate were also positively influenced by biochar addition. The study confirmed that biochar, particularly wheat-straw biochar, effectively mitigated the adverse effects of soil salinity, enhancing both soil quality and wheat growth. The study highlighted that biochar application can minimize the negative effects of salinity stress on wheat. Specifically, the types and dosages of biochar have to be optimized for different salinity levels under field conditions.

Mitigating greenhouse gas emission and enhancing fermentation by phosphorus slag addition during sewage sludge composting.

During the composting of sewage sludge (SS), a quantity of greenhouse gases has been produced. This study aimed to clarify the microbial mechanisms associated with the addition of industrial solid waste phosphorus slag (PS) to SS composting, specifically focusing on its impact on greenhouse gas emissions and the humification. The findings indicated that the introduction of PS increased the temperature and extended the high-temperature phase. Moreover, the incorporation of 10% and 15% PS resulted in a decrease of N2O emissions by 68.9% and 88.6%, respectively. Microbial diversity analysis indicated that PS improved waste porosity, ensuring the aerobic habitat. Therefore, the environmental factors of the system were altered, leading to the enrichment of various functional bacterial species, such as Firmicutes and Chloroflexi, and a reduction of pathogenic bacterium Dokdonella. Consequently, incorporating PS into SS composting represents an effective waste treatment strategy, exhibiting economic feasibility and promising application potential.

Performance analysis of snail shell biomaterials in solar still for clean water production: nature-inspired innovation for sustainability.

In this current investigation, the experimental performance of a solar still basin was significantly enhanced by incorporating snail shell biomaterials. The outcomes of the snail shell-augmented solar still basin (SSSS) are compared with those of a conventional solar still (CSS). The utilization of snail shells proved to facilitate the reduction of saline water and enhance its temperature, thereby improving the productivity of the SSSS. Cumulatively, the SSSS productivity was improved by 4.3% over CSS. Furthermore, the SSSS outperformed in energy and exergy efficiency of CSS by 4.5 and 3.5%, respectively. Economically, the cost per liter of distillate (CPL) for the CSS was 3.4% higher than SSSS. Moreover, the SSSS showed a shorter estimated payback period (PBP) of 141 days which was 6 days less than CSS. Considering the environmental impact, the observed CO2 emissions from the SSSS were approximately 14.6% higher than CSS over its 10-year lifespan. Notably, the SSSS exhibited a substantial increase in the estimated carbon credit earned (CCE) compared to the CSS. Ultimately, the research underscores the efficacy of incorporating snail shells into solar still basins as a commendable approach to organic waste management, offering economic benefits without compromising environmental considerations.

Augmentation of farmers' income in India through sustainable waste management techniques.

The Government of India has envisaged a journey of doubling farmers' income till 2022-2023 and envisioned many policy reforms for the same. Farmers in India rely on major farm produce and do not utilize the by-products or wastes emerging from their farms for monetary benefits. Sustainable utilization of agricultural, household and livestock waste have the potential in augmenting farmers' income significantly which was established by conducting case studies in Ludhiana District of Punjab on three dairy farmers, each pursuing vermicomposting, biogas production and traditional composting. Comparative economic analysis in terms of various costs were worked out for vermicomposting, composting and biogas production. On analysis, it was found that the highest net returns per metric tonne of dung were obtained from vermicomposting (INR 2224.72, USD 29.42), followed by biogas production (INR 536.66, USD 7.10) and composting (INR 45.59, USD 0.60). Net returns from the dung obtained from one cattle equivalent were highest from vermicomposting (INR 11012.34, USD 145.64), followed by biogas production (INR 2656.74, USD 35.14) and composting (INR 225.68, USD 2.98). High profitability was accorded to vermicomposting because it is sold at remunerative prices. The study emphasizes the utilization of wastes through vermicomposting clubbed with biogas production for augmenting farmers' income.

Earthworms and vermicompost: an eco-friendly approach for repaying nature's debt.

The steady increase in the world's population has intensified the need for crop productivity, but the majority of the agricultural practices are associated with adverse effects on the environment. Such undesired environmental outcomes may be mitigated by utilizing biological agents as part of farming practice. The present review article summarizes the analyses of the current status of global agriculture and soil scenarios; a description of the role of earthworms and their products as better biofertilizer; and suggestions for the rejuvenation of such technology despite significant lapses and gaps in research and extension programs. By maintaining a close collaboration with farmers, we have recognized a shift in their attitude and renewed optimism toward nature-based green technology. Based on these relations, it is inferred that the application of earthworm-mediated vermitechnology increases sustainable development by strengthening the underlying economic, social and ecological framework.

Insights into organic waste management practices followed by dairy farmers of Ludhiana District, Punjab: Policy challenges and solutions.

The study was conducted in Ludhiana District of Punjab (India) to understand the organic waste management practices followed by dairy farmers of the area. To investigate the practices pertaining to organic waste management, an ex-post facto research design was used and a total of 80 dairy farmers were selected randomly for the study, grouped as small and large dairy farmers. Results revealed that the majority of the farmers were using paddy straw as animal bedding followed by in situ burning. As far as paddy stubbles were concerned, most of the farmers were mulching them followed by in situ burning. All farmers were found to be using wheat straw as livestock feed and mulching wheat stubbles. For household waste, the majority of the farmers were found to be feeding kitchen waste to their livestock, preparing farmyard manure from garden waste and paper waste. For dairy waste management, all the farmers were preparing farmyard manure from dung and discarding livestock urine in drains. A little more than half of the farmers were producing biogas from the dairy waste. The majority of the dairy farmers of the research area were found to have low organic waste utilization scores. Relational analysis was carried out and social participation and knowledge level were found to be highly significant (p < 0.01) with a positive effect on the organic waste utilization score. Therefore, the study was concluded with the impression that the knowledge level of the farmers needs to be enhanced for better and effective utilization of organic waste.

Identification of locally available structural material as co-substrate for organic waste composting in Tamil Nadu, India.

Owing to the lack in structural strength while composting certain kinds of organic wastes, 11 co-substrates were tested that are generally locally available in rural areas of northern Tamil Nadu, India. In addition to the classical composting parameters such as carbon/nitrogen ratio, moisture content, dry matter and organic dry matter, a compression test was conducted to evaluate the structural strength and the suitability as bulking agent for composting processes. Additionally, with respect to the climatic conditions in India, the water holding capacity was also evaluated.

Assessment of a composting process for the treatment of beef cattle manure.

The intensive breeding of beef cattle in Juncosa de les Garrigues (Catalonia, Spain) leads to the production of a large volume of manure that needs appropriate management. Land application in the area at agronomic rates is not enough to ensure good management practices, making necessary extended on-farm storage and the export of part of the production to long distances. In this context, the implementation of a collective treatment based on composting could help in enhancing the handling of manure. We assessed a full-scale composting process based on turned windrows (W), and involving treatment of beef cattle manure (CM) alone (two typologies were considered according to carbon-to-nitrogen ratios of ~25 (CM1, W1) and ~14 (CM2, W2)), or mixed with bulking agent (CM2/BA, W3) and dewatered digested sewage sludge (CM2/BA/DDSS, W4). Composting significantly improved the transportability of nutrients (final volumes were 40-54% of the initial volume). Temperature >55°C was reached in all the treatments but following different time patterns. Under the applied conditions of turning and rewetting, 14 weeks of processing did not ensure the production of stable, and mature, compost. Thus, only compost from W1 attained the maximum degree of stability as well as concentration of ammonium-N < 0.01% (with ammonium-N/nitrate-N ratio of 0.2) and low phytotoxicity. However, high pH, salinity, and heavy metal contents (Cu and Zn) may limit its final use. Addition of BA was advised to be kept to minimum, whereas use of DDSS as a co-substrate was not recommended in agreement to the higher loss of N and levels of heavy metals in the final compost.

Inhibition of pathogenic microorganisms in solid organic waste via black soldier fly larvae-mediated management.

Inadequately managed solid organic waste generation poses a threat to the environment and human health globally. Biotransformation with the black soldier fly larvae (BSFL) is emerging as talent technology for solid waste management. However, there is a lack of understanding of whether BSFL can effectively suppress potential pathogenic microorganisms during management and the underlying mechanisms. In this study, we investigated the temporal variations of microorganisms in two common types of solid waste, i.e., kitchen waste (KW) and pig manure (PM). Natural composting and composting with BSFL under three different pH levels (pH 5, 7, and 9) were established to explore their impact on microbial communities in compost and the gut of BSFL. The results showed that the compost of kitchen waste and pig manure led to an increase in relative abundance of various potentially pathogenic bacteria. Temporal gradient analyses revealed that the most substantial reduction in the relative abundance and diversity of potentially pathogenic microorganisms occurred when the initial pH of both two wastes were adjusted to 7 upon the introduction of BSFL. Through network and pls-pm analysis, it was discovered that the gut microbiota of BSFL occupied an ecological niche in the compost, inhibiting the proliferation of potentially pathogenic microorganisms. This study has revealed the potential of BSFL in reducing public health risks during the solid waste management process, providing robust support for sustainable waste management.

Responses of synanthropic vegetation to composting facility.

Composting facilities are habitats where biological materials are bio-oxidized. Biological waste represents a source of plant species diaspores and may promote changes in the species composition of the surrounding. The studied composting facility is situated in the Bohemian-Moravian Highlands, Czech Republic. Four sites, the composting pile and three habitats nearby were chosen of different use and disturbance conditions. Phytosociological plots were recorded in each of the habitat and the results were processed using multivariate analyses of ecological data. The information about plant species indication values was also analysed: (i) the relationship between soil disturbance and plant species occurrence, (ii) seed dormancy, (iii) seed bank, and (iv) vector of seed dispersion. During the research, 119 plant taxa were found in total. Conditions of the composting process (frequent disturbances, excessive available nutrients, enough water, and supply of new diaspores) represent a challenge for plant species. The presence of plant diaspores in the biowaste is a reason why the fundamental principle of appropriate composting process has to be adhered to. Another important task is to give attention to the methods determining the share of living diaspores in the final compost, which is still missing in practice. Compost might become a vehicle for spreading weeds. The capacity of vegetation to survive and multiply on the premises of composting facilities increases the importance of vegetation monitoring and control of the adjacent areas. The usual occurrence of rural brownfields near composting facilities increases the risk of diaspores being transmitted into biowaste or compost, thus increasing the share of undesirable viable diaspores. Composting facilities generate specific synanthropic conditions for the vegetation. Therefore, the composting facility projects should take into consideration the surrounding areas and vegetation management. It is recommended that the project should include semi-natural vegetation, which can create efficient barriers to the spreading of undesirable ruderal plant species. The novelty of this study is the confirmation that composting facilities and compost become a new factor affecting vegetation, which has been disregarded so far. The link between composting facilities and vegetation has to be included in the legislation related to parameters of compost quality. Moreover, the issue of weeds, their reproductive organs and their spread should be considered in the guidelines for the design, location, construction, and operation of composting facilities.

Food industry waste - An opportunity for black soldier fly larvae protein production in Tanzania.

Black soldier fly larvae composting is an emerging treatment option with potential to improve biowaste valorization in cities of low-income countries. This study surveyed the current generation and management status of food industry biowaste and their availability and suitability as potential feedstock for black soldier fly larvae (BSFL) composting treatment in three Tanzania cities, Dar es Salaam, Mwanza, and Dodoma. Biowaste-generating food industry companies (n = 29) in the three cities were found to produce banana peels, mango seeds, sunflower press cake, brewery waste, and coffee husks in large quantities (~100,000-1,000,000 kg y-1). Around 50 % of these companies (16/29), primarily vegetable oil companies (10/11), either sold or gave away their waste as animal feed, while most companies (9/11) with unutilized food industry waste landfilled the generated biowaste. Multi-criteria analysis based on substrate availability criteria identified banana peels, mango seeds, and coffee husks with total score points of ≥10/12 as the most suitable feedstock for BSFL composting. However, multi-criteria analysis based on physical-chemical criteria identified brewery waste and sunflower press cake with total score points of ≥11/15 as the most suitable feedstock. Combined availability and physical-chemical properties of individual biowastes showed that all identified types of food industry biowaste can be suitable feedstock for producing BSFL biomass for protein production, but certain waste streams needed to be mixed with other waste streams prior to BSFL-composting to ensure sufficient availability and provide a balanced nutritional profile compared with the single-source biowastes. This study concluded that large volumes of food industry waste are being generated from food industry companies in Tanzania and there is need to establish new biowaste management interventions for resource recovery. Furthermore, for interested stakeholders in the waste management business, multi-stream BSFL-composting can be a suitable solution for managing and closing nutrient loops of the unutilized food industry biowaste in Tanzania and in other similar settings globally.

Recent trends and advances in composting and vermicomposting technologies: A review.

Composting technologies have come a long way, developing from static heaps and windrow composting to smart, artificial intelligence-assisted reactor composting. While in previous years, much attention has been paid to identifying ideal organic waste streams and suitable co-composting candidates, more recent efforts tried to determine novel process-enhancing supplements. These include various single and mixed microbial cultures, additives, bulking agents, or combinations thereof. However, there is still ample need to fine-tune the composting process in order to reduce its impact on the environment and streamline it with circular economy goals. In this review, we highlight recent advances in integrating mathematical modelling, novel supplements, and reactor designs with (vermi-) composting practices and provide an outlook for future developments. These results should serve as reference point to target adjusting screws for process improvement and provide a guideline for waste management officials and stakeholders.

The effect of circular soil biosolarization treatment on the physiology, metabolomics, and microbiome of tomato plants under certain abiotic stresses.

Soil biosolarization (SBS) is an alternative technique for soil pest control to standard techniques such as soil fumigation and soil solarization (SS). By using both solar heating and fermentation of organic amendments, faster and more effective control of soilborne pathogens can be achieved. A circular economy may be created by using the residues of a given crop as organic amendments to biosolarize fields that produce that crop, which is termed circular soil biosolarization (CSBS). In this study, CSBS was employed by biosolarizing soil with amended tomato pomace (TP) residues and examining its impact on tomato cropping under conditions of abiotic stresses, specifically high salinity and nitrogen deficiency. The results showed that in the absence of abiotic stress, CSBS can benefit plant physiological performance, growth and yield relative to SS. Moreover, CSBS significantly mitigated the impacts of abiotic stress conditions. The results also showed that CSBS impacted the soil microbiome and plant metabolome. Mycoplana and Kaistobacter genera were found to be positively correlated with benefits to tomato plants health under abiotic stress conditions. Conversely, the relative abundance of the orders RB41, MND1, and the family Ellin6075 and were negatively correlated with tomato plants health. Moreover, several metabolites were significantly affected in plants grown in SS- and CSBS-treated soils under abiotic stress conditions. The metabolite xylonic acid isomer was found to be significantly negatively correlated with tomato plants health performance across all treatments. These findings improve understanding of the interactions between CSBS, soil ecology, and crop physiology under abiotic stress conditions.

Growth Performance, Waste Reduction Efficiency and Nutritional Composition of Black Soldier Fly (Hermetia illucens) Larvae and Prepupae Reared on Coconut Endosperm and Soybean Curd Residue with or without Supplementation.

Black soldier fly (BSF, Hermetia illucens) larvae are considered as insects with a high potential to convert organic waste into high-value products. The objective of this study was to investigate the growth performance, waste reduction efficiency, and nutritional composition of BSF reared on different ratios of coconut endosperm (C) and soybean curd residue (S), with or without supplementation, compared to standard diets (Gainesville: G and starter chicken diet: CK). Seven-day-old larvae were randomly divided into eight experimental groups (G, CK, and three different ratios of C and S with or without supplementation) with three replicates with an equal weight of larvae. The supplement contained calcium, phosphorus, amino acids, and a mineral-vitamin premix which was formulated to correlate with CK. Each replicate was terminated, measured, and evaluated when 40% of larvae had reached prepupal stage. The highest larval weight gain was presented in BSF fed CK, followed by those fed coconut endosperm and soybean curd residue at a ratio of 20:80 (C20S80), and coconut endosperm and soybean curd residue at a ratio of 50:50 (C50S50) without supplementation (numbers after C and S represent their percentage in the formulation; p < 0.001). Harvesting was delayed in the BSF fed C80S20 with and without supplementation (p < 0.001). The number of total larvae and prepupae was not significantly different between groups (p > 0.05). The greatest waste reduction efficiency was observed in the G, C50S50, and C20S80 groups without supplementation (p < 0.001). All groups with supplementation had a higher proportion of ash in both larvae and prepupae compared to non-supplemented groups (p < 0.001), but lower growth performance. The highest percentage of crude protein in larvae was presented in the Gainesville and C20S80 groups followed by the CK and C50S50 groups (p < 0.001). Equal proportions of C and S without supplementation are suggested as a rearing substrate. However, growth performance was lower than for CK; therefore, further studies could investigate cost-efficient techniques to promote this parameter.

The implications of facility design and enabling policies on the economics of dry anaerobic digestion.

Diverting organic waste from landfills provides significant emissions benefits in addition to preserving landfill capacity and creating value-added energy and compost products. Dry anaerobic digestion (AD) is particularly attractive for managing the organic fraction of municipal solid waste because of its high-solids composition and minimal water requirements. This study utilizes empirical data from operational facilities in California in order to explore the key drivers of dry AD facility profitability, impacts of market forces, and the efficacy of policy incentives. The study finds that dry AD facilities can achieve meaningful economies of scale with organic waste intake amounts larger than 75,000 tonnes per year. Materials handling costs, including the disposal of inorganic residuals from contaminated waste streams and post-digester mass (digestate) management, are both the largest and the most uncertain facility costs. Facilities that utilize the biogas for vehicle fueling and earn associated fuel credits collect revenues that are 4-6x greater than those of facilities generating and selling electricity and 10-12x greater than facilities selling natural gas at market prices. The results suggest important facility design elements and enabling policies to support an increased scale of organic waste handling infrastructure.

Pre-treatment of banana peel to improve composting by black soldier fly (Hermetia illucens (L.), Diptera: Stratiomyidae) larvae.

Use of black soldier fly (Hermetia illucens (L.), Diptera: Stratiomyidae) larvae (BSFL) is among the solutions being explored to shift the value chain in organic waste management by producing valuable products. Although BSFL consume a range of substrates, nutrient-imbalanced materials with high hemicellulose and lignin content, e.g. manure and banana peel, yield low conversion into larval biomass. This study explored pre-treatment methods to improve the nutrient composition and digestibility of banana peel to achieve higher substrate conversion into BSFL biomass. The pre-treatment methods evaluated were microbial, chemical (non-protein nitrogen), heat-based, and combinations of these. All pre-treatments tested except heating resulted in more efficient BSFL conversion in terms of final larvae weight. The low BSFL responses in pre-treatments were caused by the observed high amounts of tannins and phenolic compounds mainly from the heating pre-treatment. Waste to biomass conversion ratio correlated negatively with substrate volatile solids (VS) and positively with the decrease in VS in pre-treatment. Microbial - 14 days pre-treatments provided the optimum pre-treatment time for the microorganisms to achieve maximum degradation of the substrates, facilitating larval assimilation of the released nutrients. Rhizopus oligosporus-14 days and ammonia + Rhizopus resulted in the most efficient BSFL treatment, measured as protein produced per kg incoming material.

Reactor performance and energy analysis of solid state anaerobic co-digestion of dairy manure with corn stover and tomato residues.

Anaerobic co-digestion is commonly believed to be benefical for biogas production. However, additional of co-substrates may require additional energy inputs and thus affect the overall energy efficiency of the system. In this study, reactor performance and energy analysis of solid state anaerobic digestion (SS-AD) of tomato residues with dairy manure and corn stover were investigated. Different fractions of tomato residues (0, 20, 40, 60, 80 and 100%, based on volatile solid weight (VS)) were co-digested with dairy manure and corn stover at 15% total solids. Energy analysis based on experimental data was conducted for three scenarios: SS-AD of 100% dairy manure, SS-AD of binary mixture (60% dairy manure and 40% corn stover, VS based), and SS-AD of ternary mixture (36% dairy manure, 24% corn stover, and 40% tomato residues, VS based). For each scenario, the energy requirements for individual process components, including feedstock collection and transportation, feedstock pretreatment, biogas plant operation, digestate processing and handling, and the energy production were examined. Results showed that the addition of 20 and 40% tomato residues increased methane yield compared to that of the dairy manure and corn stover mixture, indicating that the co-digestion could balance nutrients and improve the performance of solid-state anaerobic digestion. The energy required for heating substrates had the dominant effect on the total energy consumption. The highest volatile solids (VS) reduction (57.0%), methane yield (379.1 L/kg VSfeed), and net energy production were achieved with the mixture of 24% corn stover, 36% dairy manure, and 40% tomato residues. Thus, the extra energy input for adding tomato residues for co-digestion could be compensated by the increase of methane yield.

A dynamic model for organic waste management in Quebec (D-MOWIQ) as a tool to review environmental, societal and economic perspectives of a waste management policy.

A dynamic systems model of organic waste management for the province of Quebec, Canada, was built. Six distinct modules taking into account social, economical and environmental issues and perspectives were included. Five scenarios were designed and tested to identify the potential consequences of different governmental and demographic combinations of decisions over time. Among these scenarios, one examines Quebec's organic waste management policy (2011-2015), while the other scenarios represent business as usual or emphasize ecology, economy or social benefits in the decision-making process. Model outputs suggest that the current governmental policy should yield favorable environmental benefits, energy production and waste valorization. The projections stemming from the current policy action plan approach the benefits gained by another scenario emphasizing the environmental aspects in the decision-making process. As expected, without the current policy and action plan in place, or business as usual, little improvements are expected in waste management compared to current trends, and strictly emphasizing economic imperatives does not favor sustainable organic waste management.

Microbial diversity of vermicompost bacteria that exhibit useful agricultural traits and waste management potential.

Vermicomposting is a non-thermophilic, boioxidative process that involves earthworms and associated microbes. This biological organic waste decomposition process yields the biofertilizer namely the vermicompost. Vermicompost is a finely divided, peat like material with high porosity, good aeration, drainage, water holding capacity, microbial activity, excellent nutrient status and buffering capacity thereby resulting the required physiochemical characters congenial for soil fertility and plant growth. Vermicompost enhances soil biodiversity by promoting the beneficial microbes which inturn enhances plant growth directly by production of plant growth-regulating hormones and enzymes and indirectly by controlling plant pathogens, nematodes and other pests, thereby enhancing plant health and minimizing the yield loss. Due to its innate biological, biochemical and physiochemical properties, vermicompost may be used to promote sustainable agriculture and also for the safe management of agricultural, industrial, domestic and hospital wastes which may otherwise pose serious threat to life and environment.