Organic Waste Streams Research Articles

Synthesis of sustainable mesoporous sulfur-doped biobased carbon with superior performance sodium diclofenac removal: Kinetic, equilibrium, thermodynamic and mechanism

Over the last years, the strategy of employing inevitable organic waste and residue streams to produce valuable and greener materials for a wide range of applications has been proven an efficient and suitable approach. In this research, sulfur-doped porous biochar was produced through a single-step pyrolysis of birch waste tree in the presence of zinc chloride as chemical activator. The sulfur doping process led to a remarkable impact on the biochar structure. Moreover, it was shown that sulfur doping also had an important impact on sodium diclofenac (S-DCF) removal from aqueous solutions due to the introduction of S-functionalities on biochar surface. The adsorption experiments suggested that General and Liu models offered the best fit for the kinetic and equilibrium studies, respectively. The results showed that the kinetic was faster for the S-doped biochar while the maximum adsorption capacity values at 318 K were 564 mg g−1 (non-doped) and 693 mg g−1 (S-doped); highlighting the better affinity of S-doped biochar for the S-DCF molecule compared to non-doped biochar. The thermodynamic parameters (ΔH0, ΔS0, ΔG0) suggested that the S-DCF removal on both adsorbents was spontaneous, favourable, and endothermic.

Neodymium adsorption from aqueous solution by β-cyclodextrin nanosponges and a polymer valorized from potato peels waste: experiments and conventional and statistical physics interpretations.

Using organic waste and residue streams to be turned into valuable and greener materials for various applications has proven an efficient and suitable strategy. In this work, two green materials (nanosponges and a polymer) were synthesized using potato peels and applied for the first time to adsorb and recover Neodymium (Nd3+) from aqueous solutions. The recovery of Nd3+ that belongs to the rare earth elements has attracted important interest due to its/their importance in several industrial and technological applications. The fine potato peel waste (FPPW) polymer presented an irregular shape and porous surface. At the same time, the β-cyclodextrin (β-CD) nanosponges had uniform distribution with regular and smooth shapes. β-CD nanosponges exhibited a much higher total carboxyl content (4.02mmolg-1) than FPPW (2.50mmolg-1), which could impact the Nd3+ adsorption performance because carboxyl groups can interact with cations. The adsorption capacity increased with the increase of the pH, reaching its maximum at pHs 6-7 for β-CD nanosponges and 4-7 for FPPW polymer. The kinetic and equilibrium data were well-fitted by General order and Liu models. β-CD nanosponges attained adsorption capacity near 100mg Nd per gram of adsorbent. Thermodynamic and statistical physical results corroborated that the adsorption mechanism was due to electrostatic interaction/complexation and that the carboxyl groups were important in the interactions. β-CD nanosponges (three cycles of use) were more effective than FPPW (one cycle of use) in the regeneration. Finally, β-CD nanosponges could be considered an eco-friendly adsorbent to recover Nd3+ from aqueous matrices.

Monitoring compositional changes in black soldier fly larvae after processing (drying and blanching) using near infrared spectroscopy

Determining which processing technique is better to guarantee the safety and nutritional value of black soldier fly larvae (BSFL) is of critical importance for the food waste industry. This study evaluates the utilization of near infrared reflectance (NIR) spectroscopy as a proxy technique to monitor the effect of two processing treatments commonly used by the food waste industry, namely blanching and the combination of blanching plus drying, on the composition of BSFL. The 5th instar BSFL samples were harvested from a commercial waste processing facility and subjected to drying (2 and 12 hrs at 100 °C) and blanching (4 s and 5 min) treatments. The samples were scanned using a NIR instrument (11,550 to 3950 cm−1) where the data was analysed using principal component analysis (PCA) and linear discriminant analysis (LDA). A correct classification rate above 83 % was obtained for the identification of samples according to the drying treatment, while 56 % of the samples were correctly classified according to the blanching treatment. Overall, NIR spectroscopy has shown great potential as a rapid tool for real-time monitoring of the processing of BSFL (drying and blanching), and thereby assisting in improving the treatment of BSFL samples intended to be used by the animal feed industry.

A mathematical programming based decision support system for waste to resource market trading

In a linear economy, consumers typically dispose end-of-life products which are eventually incinerated or landfilled. Digital platforms could unlock rich waste reutilization opportunities and economic benefits by connecting the waste producers with potential waste buyers in online marketplaces. While previous studies mostly focus on input-output matching, this study proposes a decision support system that can be incorporated to an online marketplace to optimize the waste trading based on economic considerations. Moreover, the decision support system could facilitate higher level decisions such as capacity planning and incentive design. Based on a case study on Singapore’s organic waste streams, the waste trading platform presents economic benefits for agents that sell their waste. Additionally, enforcing waste reutilization targets would require relevant policy support in terms of incentives or levies, where the levies can be implemented as co-payment rate for the agents. For instance, results showed that when the food waste reutilization target is set as 6 t/d, increasing the co-payment rate from 0 to 20% allows the waste trading network to be self-sustaining without external funding. Finally, sensitivity analyses show that collecting more waste records in the database helps in optimizing the investment decisions, preferably when the number of records exceeds 64.

Municipal Solid Waste Management in a Decentralized Composting Scenario: Assessment of the Process Reproducibility and Quality of the Obtained Composts

Over the last several years, the models for organic waste management have changed to implement circular economy in the productive cycle. In this context, new scenarios have emerged, where the management of different organic waste streams by composting is conducted with decentralized models that manage organic wastes in a more local way. However, in these new models, the standardization of the process control and of the end-product characteristics is necessary to guarantee the quality and agronomic value of the compost obtained, avoiding potential risks for human health and the environment. Thus, the aim of this work was to study two different scenarios of community composting of the organic fraction of municipal solid waste separately collected in order to guarantee the effectiveness and reproducibility of the composting processes and the quality of the composts obtained. For this, the development of the process and the characteristics of the composts at agronomic, hygienic–sanitary and environmental levels were assessed in real conditions and during three cycles of the process. The results obtained show high similarity among the different composting cycles, indicating an important degree of reproducibility among the processes. In addition, the composts obtained showed a good sanitary quality, absence of phytotoxicity and low contents of potentially toxic elements, which guarantee their use in agriculture without posing any risk to human health and to the environment.

Exclusive D-lactate-isomer production during a reactor-microbiome conversion of lactose-rich waste by controlling pH and temperature

Lactate is among the top-ten-biobased products. It occurs naturally as D- or L-isomer and as a racemic mixture (DL-lactate). Generally, lactate with a high optical purity is more valuable. In searching for suitable renewable feedstocks for lactate production, unutilized organic waste streams are increasingly coming into focus. Here, we investigated acid whey, which is a lactose-rich byproduct of yogurt production, that represents a considerable environmental footprint for the dairy industry. We investigated the steering of the lactate-isomer composition in a continuous and open culture system (HRT = 0.6 d) at different pH values (pH 5.0 vs. pH 6.5) and process temperatures (38°C to 50°C). The process startup was achieved by autoinoculation. At a pH of 5.0 and a temperature of 47°C-50°C, exclusive D-lactate production occurred because of the dominance of Lactobacillus spp. (> 95% of relative abundance). The highest volumetric D-lactate production rate of 722 ± 94.6 mmol C L−1 d−1 (0.90 ± 0.12 g L−1 h−1), yielding 0.93 ± 0.15 mmol C mmol C−1, was achieved at a pH of 5.0 and a temperature of 44°C (n = 18). At a pH of 6.5 and a temperature of 44°C, we found a mixture of DL-lactate (average D-to-L-lactate production rate ratio of 1.69 ± 0.90), which correlated with a high abundance of Streptococcus spp. and Enterococcus spp. However, exclusive L-lactate production could not be achieved. Our results show that for the continuous conversion of lactose-rich dairy waste streams, the pH was a critical process parameter to control the yield of lactate isomers by influencing the composition of the microbiota. In contrast, temperature adjustments allowed the improvement of bioprocess kinetics.

Towards a circular economy with waste‐to‐resource system optimization

AbstractMotivated by mounting pressures to achieve environmental sustainability, and the emergence of online waste exchange platforms, in this work we propose an optimization‐based framework for studying waste‐to‐resource formation in the industry. We first develop a linear programming market clearing model comprising self‐interested agents participating in waste‐to‐resource trading. We then embed this in a bi‐level capacity optimization problem under uncertainties in the agents' reserve prices, the goal of which is to maximize the economic savings achieved by waste‐to‐resource. We show that the resulting robust optimization models admit linear mixed integer programming formulations that can be readily computed using available solvers. Furthermore, we provide the formulas for applying an equitable levy and incentive scheme, to enable capacity cost‐sharing among the agents. Numerical studies based on a case of organic waste streams demonstrate the usefulness of the proposed models in generating valuable insights for decision support in the design of waste‐to‐resource markets.

Nitrogen fertilizer replacement values of organic amendments: determination and prediction

AbstractThe nitrogen fertilizer replacement value (NFRV) quantifies the value of organic amendments as a nitrogen (N) fertilizer, and is commonly defined as the extent to which organic fertilizer N can replace mineral fertilizer N. NFRVs can be calculated by comparing the crop N uptake from equal N application rates of mineral and organic fertilizer, or by comparing the N rates of both fertilizers needed to obtain equal crop N uptake. Currently, NFRVs are mainly known for animal manure, whereas other organic waste products may become available as fertilizer products in the future. In this study, a pot experiment with spring wheat was performed to (1) assess NFRVs of a range of organic amendments; (2) compare NFRVs based on equal N application with NFRVs based on equal N uptake; and (3) assess which product characteristics explain observed variation. Observed NFRVs varied between 6.2 and 78.8%, with the lowest value for raw food waste and the highest for fishmeal. NFRVs were overestimated when calculated based on equal N application rate (with on average 6.9% point), and more so at high N application rate (9.0% point). NFRVs should therefore be calculated based on equal N uptake from organic and mineral fertilizers. Nitrogen concentration of the organic fertilizer provided the best explanation of variation observed in NFRVs (R2 = 0.86). These findings give valuable insights into the large variation in value of organic waste streams as organic fertilizer and can support decisions on sustainable N application rates, to increase crop N uptake and reduce N losses to the environment.

A Sustainable Approach to the Conversion of Waste into Energy: Landfill Gas-to-Fuel Technology

Landfill gas (LFG) is a methane-rich gas produced by the decomposition of organic waste in landfills. It has the potential to be a greenhouse gas, but it can also be a valuable source of energy. LFG can be used to generate electricity, heat, or fuel. Renewable natural gas, abundant in methane derived from organic matter or waste streams, can undergo processing to align with established specifications for conventional fossil natural gas pipelines and vehicle use. This article assesses the present state of understanding concerning the transformation of landfill gas into a valuable fuel resource. This study shows the methods for LFG collection and conversion into usable fuels, along with the environmental benefits and challenges associated with its utilization and usage. In this study, a thorough examination was conducted concerning the waste generated in residential communities, specifically within the rural districts of Adana, known as the Yedigoze region. This research focused on assessing the gas potential derived from these waste materials and their potential environmental implications when employed as a fuel source for municipal buses. The transitioning analysis of 50 diesel buses to compressed natural gas (CNG) buses resulted in a remarkable reduction of 950,625 kg of CO2 emissions in one year.

A techno-economic assessment on biomass waste-to-energy potential in Cameroon

Biomass waste-to-energy (WtE) offers a critical solution to carbon neutrality through improving the resource recycling and recovery. This study comprehensively assessed how WtE can be implemented in generating electricity for Cameroon with an estimation to the energy potential of anaerobic digestion of three organic waste streams including municipal solid waste, wastewater sludge, and livestock manure. We assessed the energy potential in terms of the theoretical, technical, and economic potentials. The findings highlighted a theoretical energy potential of 936.37 TWh yr−1 in Cameroon. If only applied to a fraction of organic wastes, the technical potential could reach 48.64 TWh yr−1. Furthermore, considering the economic costs of technology installation, 17.06 TWh yr−1 could be generated, and this economic generation potential could supply to 38.9% of the country’s current electricity demand. This study implies that WtE would significantly reduce fossil fuels consumption and greenhouse gases emissions from poorly disposed wastes, to enable decarbonization transition and improve human health in African countries.

Algae Cultivation as Measure for the Sanitation of Organic Waste—A Case Study Based on the Alga Galdieria sulphuraria Grown on Food Waste Hydrolysate in a Continuous Flow Culture

Due to its growth under harsh acidic conditions, the microalga Galdieria sulphuraria may offer the opportunity to combine sanitation and the utilization of organic waste streams. To further deepen the knowledge of alternative waste treatment strategies that allow for holistic utilization, the control and removal of microbial contaminants via non-sterile heterotrophic G. sulphuraria on food waste hydrolysate were investigated in a continuous flow bioreactor culture. Furthermore, a substrate reservoir and harvested biomass were stored under non-sterile conditions over a period of 12 days. Despite the non-sterile conditions, the microbial load of the biomass could be kept under control. Neither the pathogen Salmonella sp. nor the coliform bacteria Escherichia coli could be found. Only nine counts per g of biomass were found for species belonging to Enterococcus spp., Enterobacteriacae, and moulds. Aerobic spore formers were counted with 2700 counts per g of biomass. Most of the aerobic mesophilic counts were formed by yeasts (1.5 × 106 vs. 1.3 × 106 counts per g biomass). The results revealed that, when using acidic growth conditions, contamination will not take over the culture; thus, the sterilization of waste materials can be skipped. It is assumed that such an approach can result in efficient processes for future waste-based bioeconomy strategies.

Modeling National Embedded Phosphorus Flows of Corn Ethanol Distillers' Grains to Elucidate Nutrient Reduction Opportunities.

Freshwater quality and ecosystem impairment associated with excess phosphorus (P) loadings have led to federally mandated P reduction for certain organic waste streams. Phosphorus reduction from livestock and poultry feeds such as corn ethanol distillers' grains (DGs) presents a centralized strategy for reducing P loss from animal manurein agriculturally intensive states, but little is known about the actual distribution and geospatial P contributions of DGs as animal feed. Here, a county-level flow network for corn ethanol DGs was simulated in the United States to elucidate opportunities for P reduction and the potential for nutrient trading between centralized sources. Overall, the estimated P in DGs that was transferred to US animal feeding operations was nearly twice that present in all human waste prior to treatment. Simulation results suggest that Midwestern states account for an estimated 63% of domestic DG usage, with 72% utilized within the state of production. County-level data were also used to highlight the potential of using nutrient trading markets to incentivize P recovery from DGs at biorefineries within an agriculturally intensive watershed region in Iowa. In summary, corn ethanol biorefineries represent a key leverage point for sustainable P management at the national and local scales.

Co-production of lactate and volatile fatty acids through repeated-batch fermentation of fruit and vegetable waste: Effect of cycle time and replacement ratio

In this study, repeated-batch fermentation was used to convert fruit and vegetable waste to lactate and volatile fatty acids (VFAs), which are essential carbon sources for medium-chain fatty acids (MCFAs) production. The effect of cycle time and replacement ratio on acidification in long-term fermentation was investigated. The results showed that they had a significant impact on product yield, productivity, and type of products. Considering the yield, productivity, and lactate/VFAs ratio, a replacement ratio of 30% and a cycle time of 2 d may be more suitable for further production of MCFAs. Its productivity and lactate/VFAs ratio were 4.07 ± 0.24 g/(L·d) and 5 ± 0.6, respectively. The lactic acid bacteria, such as Enterococcus (63%) and Lactobacillus (33%), stabilized in the reactor, resulting in the generation of both lactate and VFAs by heterolactic fermentation. The present study demonstrated a new strategy with the potential to recover high-value products from organic waste streams.

Near Infrared Spectroscopy for Prediction of Yeast and Mould Counts in Black Soldier Fly Larvae, Feed and Frass: A Proof of Concept.

The use of black soldier fly larvae (BSFL) grown on different organic waste streams as a source of feed ingredient is becoming very popular in several regions across the globe. However, information about the easy-to-use methods to monitor the safety of BSFL is a major step limiting the commercialization of this source of protein. This study investigated the ability of near infrared (NIR) spectroscopy combined with chemometrics to predict yeast and mould counts (YMC) in the feed, larvae, and the residual frass. Partial least squares (PLS) regression was employed to predict the YMC in the feed, frass, and BSFL samples analyzed using NIR spectroscopy. The coefficient of determination in cross validation (R2CV) and the standard error in cross validation (SECV) obtained for the prediction of YMC for feed were (R2cv: 0.98 and SECV: 0.20), frass (R2cv: 0.81 and SECV: 0.90), larvae (R2cv: 0.91 and SECV: 0.27), and the combined set (R2cv: 0.74 and SECV: 0.82). However, the standard error of prediction (SEP) was considered moderate (range from 0.45 to 1.03). This study suggested that NIR spectroscopy could be utilized in commercial BSFL production facilities to monitor YMC in the feed and assist in the selection of suitable processing methods and control systems for either feed or larvae quality control.

Enhanced ethanol-driven carboxylate chain elongation by Pt@C in simulated sequencing batch reactors: Process and mechanism

Carboxylate chain elongation can create value-added bioproducts from the organic waste. The effects of Pt@C on chain elongation and associated mechanisms were investigated in simulated sequencing batch reactors. 5.0 g/L of Pt@C greatly increased the synthesis of caproate, with an average yield of 21.5 g COD/L, which was 207.4% higher than the trial without Pt@C. Integrated metagenomic and metaproteomic analyses were used to reveal the mechanism of Pt@C-enhanced chain elongation. Pt@C enriched chain elongators by increasing the relative abundance of dominant species by 115.5%. The expression of functional genes related to chain elongation was promoted in the Pt@C trial. This study also demonstrates that Pt@C may promote overall chain elongation metabolism by enhancing CO2 uptake of Clostridium kluyveri. The study provides insights into the fundamental mechanisms of how chain elongation can perform CO2 metabolism and how it can be enhanced by Pt@C to upgrade bioproducts from organic waste streams.

Bioponics—An Organic Closed-Loop Soilless Cultivation System: Yields and Characteristics Compared to Hydroponics and Soil Cultivation

Sustainable food production has become increasingly important. Soilless cultivation systems offer several advantages, such as water and nutrient use efficiency, and can be implemented where traditional agriculture is impossible. Bioponic systems use locally or regionally available nutrient sources from organic waste streams (either fluid or solid) and can thus contribute to closing nutrient cycles locally. Bioponics harnesses the metabolic processes of microorganisms which release nutrients from organic matter. This study aimed to set up a bioponic system, by using biogas digestate concentrate and biochar as nutrient sources, and promoting nutrient release from the organic sources by including a biofilter in the system. The development of water quality, plant growth, and quality was monitored extensively. In addition, the influence of either the fungal biocontrol agent Trichoderma atrobrunneum or UV-C treatment of the nutrient solution on plant health and growth was investigated. Three cultivation cycles with Lactuca sativa (“HAWKING” Salanova®) in bioponic (BP), hydroponic (HP), and soil (SO) cultivation were performed. The study showed that healthy lettuces could be produced in BP systems, using a biogas digestate concentrate and biochar as nutrient sources, despite salt accumulation in the nutrient solution. In plant sap analyses, lettuces cultivated in BP systems contained less nitrate but more ammonium and chloride. The yield of the lettuces grown in the BP systems was intermediate, compared to the HP and the SO. The fungus, T. atrobrunneum, strain, T720, survived in soil and soilless cultivation systems. Compared to the HP and the SO systems, the shoot height of lettuces grown in the BP system, with the application of Trichoderma, was significantly increased. In SO systems with Trichoderma application, a significantly higher chlorophyll and flavonoid content, but significantly lower shoot height was observed. The fresh weight of lettuce roots was significantly higher in HP systems with Trichoderma treatment. Cultivating plants by using organic waste streams requires commitment and experience from producers. In BP systems, a biofilter (either within the system or externally, to increase nutrient levels) can help to rapidly convert the ammonium-rich fertilizer to plant-available nutrients. Unlike conventional HP systems, in BP systems, nutrients are released slowly over time, requiring close monitoring and adjustments. In conclusion, healthy lettuces for human consumption can be produced in BP systems, and the application of the biocontrol agent used has some beneficial influence on plant growth.

An optimization model minimizing costs of fertilizer application in Flemish horticulture

ABSTRACTThe majority of today’s fertilizers are based on mineral resources and fossil fuels. Among other factors, geopolitical sensitivities and rising fertilizer demand contribute to high and volatile prices. To reduce our dependency on non-renewable resources, valuable bio-based fertilizer components can be recovered through valorization of organic waste streams. However, from a farmer’s perspective, an optimization problem arises: the farmer wants to minimize costs while safeguarding crop nutrient uptake. Optimization research in the fertilizer domain focuses on scheduling fertilizer application or minimizing manure management costs. The model developed in this paper intends to minimize fertilizer costs for an individual vegetable farmer by considering the possibility of bio-based fertilizer prosumption through composting and anaerobic digestion as well as leaving crop residues on the field. In a Linear Programming model, these options are compared to purchasing mineral fertilizer, commercial compost or pig slurry. In addition, a distinction is made between different business models. Sensitivity analysis is carried out with respect to changing cost parameters. The results confirm that it is not optimal for a Flemish vegetable farmer to fulfil nutrient needs solely with bio-based fertilizer. Nevertheless, the study shows that it can be interesting to consider value chains involving regional cooperation.

Competitive Reactions during Ethanol Chain Elongation Were Temporarily Suppressed by Increasing Hydrogen Partial Pressure through Methanogenesis Inhibition.

Organic waste streams can be converted into high-value platform chemicals such as medium-chain carboxylic acids (MCCAs) using mixed microbial communities via chain elongation. However, the heterogeneity of waste streams and the use of complex microbial communities can lead to undesirable reactions, thus decreasing process efficiency. We explored suppressing excessive ethanol oxidation to acetate (EEO) by increasing the hydrogen partial pressure (PH2) through hydrogenotrophic methanogenesis inhibition by periodically adding 2-bromoethanesulfonate (2-BES) to an MCCA-producing bioreactor to reach 10 mM of 2-BES upon addition. The bioreactor was fed with pretreated food waste and brewery waste containing high concentrations of short-chain carboxylic acids and ethanol, respectively. While 2-BES addition initially reduced EEO, some methanogens (Methanobrevibacter spp.) persisted and resistant populations were selected over time. Besides changing the methanogenic community structure, adding 2-BES also changed the bacterial community structure due to its impact on PH2. While we demonstrated that PH2 could be manipulated using 2-BES to control EEO, methods that do not require the addition of a chemical inhibitor should be explored to maintain optimum PH2 for long-term suppression of EEO.

Dietary fishmeal replacement with Hermetia illucens (Black soldier fly, BSF) larvae meal affected production performance, whole body composition, antioxidant status, and health of snakehead (Channa striata) juveniles

Due to the market instability and increasing demand and prices of fishmeal, the aquafeed industry must seek alternative protein feedstuffs to keep producing aquafeeds in a sustainable and cost-effective way. Hermetia illucens (BSF) larvae meal is considered sustainable since its production recycles organic waste streams into a valuable nutrient. Therefore, this study assessed the effects of dietary fish meal (FM) replacement with Hermetia illucens larvae meal (HIM) on the production performance of snakehead (Channa striata) juveniles. Five isoproteic (420 g Kg−1) and isocaloric (19.5 MJ kg−1 diet) experimental diets were designed by replacing FM at 0% (control diet), 25% (HIM25), 50% (HIM50), 75% (HIM75), and 100% (HIM100) with HIM. Four hundred and fifty juveniles (16.36 ± 0.09 g fish−1) were randomly assigned to 15 tanks (400 litres; 30 fish tank−1) and fed respective diets twice daily until apparent satiety for 9 weeks. The weight gain (WG), specific growth rate (SGR), and protein efficiency ratio (PER) showed a linear decrease with increasing dietary HIM (P < 0.05), and no significant effect in fish fed control, HIM25, and HIM50 diets. Whole body proximate composition and organ somatic indices were unaffected (P > 0.05). Whole-body C12, C14, saturated fatty acid (SFA), and SFA: PUFA ratios increased linearly with increasing FM replacement whereas polyunsaturated fatty acid (PUFA) and n3/n6 fatty acid ratios decreased linearly (P < 0.05). Dietary HIM had a significant effect on protease activity (P < 0.05), but had no effect on lipase and amylase activity (P > 0.05). With increasing levels of dietary HIM, the apparent digestibility coefficient (ADC) of dry matter linearly decreased, and the ADC of crude protein showed significant linear and quadratic decrease, but the ADC of crude lipid was unaffected (P > 0.05). Aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) were unaffected by HIM levels (P > 0.05). Fish fed HIM incorporated diets had higher superoxide dismutase (SOD) and catalase (CAT) activities than fish fed a control diet, with a linear and quadratic effect (P < 0.05). The liver glutathione peroxidase (GPx) was unaffected (P > 0.05), whereas plasma GPx increased linearly and quadratically as dietary HIM levels increased (P < 0.05). Malonaldehyde (MDA) levels in liver and plasma remained unchanged among all the groups (P > 0.05). The dietary HIM did not affect the blood biochemistry (NBT, glucose, Hb, RBC, and WBC) and plasma metabolites (total protein, albumin, globulin, and total lipids) (P > 0.05). The lower plasma cholesterol was witnessed in fish fed HIM-incorporated diets than in fish fed control diets except for the HIM50 diet (P < 0.05). In conclusion, HIM can replace dietary FM up to 50% (20 g kg−1 HIM inclusion) without harming the production performance and health of snakehead juveniles.

Life cycle assessment of end-of-life options for cellulose-based bioplastics when introduced into a municipal solid waste management system

The partial degradation of cellulose-based bioplastics in industrial treatment of organic fraction of Municipal Solid Waste (MSW) opened to the investigation of further disposal routes for bioplastics in the waste management system. For this purpose, the environmental footprint of three MSW management scenarios differing only for the bioplastics final destination (organic, plastic or mixed waste streams) was assessed through a Life Cycle Assessment (LCA) approach. Results revealed how the treatment of bioplastics with organic waste achieved the worst environmental performance (5.8 kg CO2 eq/FU) for most impact categories. On the other hand, treatment with plastics and mixed waste achieved negative impact values (that mean avoided GHG emissions) of −9.8 and −7.7 kg CO2 eq/FU respectively, showing comparable benefits from these scenarios. The key reason was the lower quality of compost obtained from the organic treatment route, which reduced the environmental credits achieved by the energy recovery during anaerobic digestion.