Search Results (19)

Anaerobic digestion has the potential to convert organic waste materials into valuable energy. At the same time, using press water from biomass materials for energy generation while taking advantage of the resulting cake for other purposes is an emerging approach. Therefore, this study aimed to investigate the residual potential expected from a typical biogas feedstock after it has been mechanically separated into liquid and solid phases. Hence, in this study, the rumen contents of ruminants (cow, goat, and sheep) and their proportionate ratios were obtained from an abattoir in Ghana. Resource characterization of the waste samples was carried out in the central laboratory of the HFR, Germany. Anaerobic batch tests for biogas (biomethane) yield determination were set up using the Hohenheim Biogas Yield Test (HBT). The inoculum used was obtained from an inoculum production unit at the Hohenheim University biogas laboratory. The trial involved two different forms of the sample: mixture of rumen contents, press water, and inoculum, each in four (4) replicates. The trial was carried out at a mesophilic temperature of 37 °C. Results obtained over a seventy (70) day period were transformed into biogas yields. Overall, the results show that the current contents are suitable for biogas generation as an option as opposed to the current form of disposal at a refuse dump. However, using these mixtures in their original forms is more technically viable than using press water without further treatment. Full article

Abattoirs dispose of sheepskins as solid waste due to low price and poor demand for sheepskin leather. In principle, as an alternative to being disposed of in landfill, sheepskins can serve as a source of the protein collagen or the hydrolysis product, gelatin. In this research, sheepskins collected from abattoirs were used as a source of collagen. Three extraction methods were compared: acid extraction, acid with enzymes, and alkali extraction. The extracted material was characterized using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR), small angle X-ray scattering (SAXS), and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The collagen and gelatin extraction yield ranged from 3.1% to 4.8% with the product purity determined by hydroxyproline, ranging from 7.8% for the alkali process to 59% and 68% for the acid and acid-enzyme processes. SDS PAGE showed that the acid process produced fragments with molecular weights in the range 100 to >250 kDa, while acid–enzyme resulted in smaller fragments, below 30 kDa. The FTIR region of the amide I band at 1800–1550 cm⁻¹, which was used as an indicator of the collagen and gelatin content, showed that the gelatin dominated in the acid extracts, and the alkaline extract contained a large portion of keratin. SAXS was found to be a sensitive method for showing the presence of intact collagen fibrils in materials from all of the extraction methods, albeit at low concentrations. Herein, sheepskin is shown to be a useful source for collagen–gelatin material of varying molecular weights. Full article

Rapid urbanization worldwide results in high demand for meat products, which in turn result in high numbers of animals being slaughtered for human consumption to meet food security demands, especially in low-income countries such as South Africa. The waste produced during slaughtering can serve as feedstock for biogas production. This study aims to determine the impacts of pasteurization and sterilization pre-treatments on high-throughput red meat abattoir solid slaughter waste’s physicochemical properties and biomethane yield when used as a feedstock for biogas production. Abattoir solid slaughter waste was collected from 45 high-throughput red meat abattoirs across South Africa and the various physicochemical properties were determined using standard methods, along with the impact of sterilization and pasteurization on red meat abattoir waste. Biomethane yield analysis was performed using AMPTS II with a hydraulic retention time of 40 days. Pasteurization and sterilization pretreatment was seen to increase physicochemical parameters such as pH, volatile solids, total solids, carbon, and nitrogen analyzed in all samples. Pasteurization and sterilization were also seen to increase biomethane yield, where methane production ranged from 610.67 Nml to 1756.30 Nml, 1592.20 Nml to 3319.30 Nml, and 949.57 Nml to 3297.87 Nml for untreated, sterilized, and pasteurized samples, respectively. There was no significant difference (p < 0.05) observed in the effect pasteurized and sterilized samples had on physicochemical properties and biomethane yield. It can be concluded that pasteurization and sterilization enhance the bioavailability of the physicochemical properties and biomethane yield of red meat solid slaughter waste when valorized as feedstock for biogas production. Full article

The poultry industry has met more than one-third of the human demand for meat and all the demand for eggs during the past several decades, and it has also been recognized as a very efficient sector in the livestock industry. However, increasing poultry production has also led to the massive generation of various poultry wastes, which are a great threat to climate change, environmental safety, and human health. Traditionally, landfilling and burning are the most frequently used techniques for treating poultry waste. With rich contents of organic matter, nutrients, and keratin, poultry waste can be applied to produce value-added products that can be used in many sectors by using a variety of emerging technological processes. Considering the massive generation, profound environmental pollution, and wide range of applications of poultry waste, this paper categorizes poultry waste as litter and manure waste, feather waste, mortality waste, abattoir waste, and hatchery waste. This paper also reviews modeling and simulation studies on poultry waste-to-wealth, and six current or emerging technological processes for poultry waste-to-wealth are described: anaerobic digestion, pyrolysis, gasification, hydrolysis, enzymatic treatment, and microbial conversion. Finally, the economic, environmental, and social impacts of the sector of poultry waste-to-wealth are discussed. For further research, we suggest a focus on the poultry waste-to-wealth projects in different regions, the behavior strategy of different stakeholders, and policymaking for the commercialized application of poultry waste-to-wealth technologies. Full article

Recycling bioresources is the only way to sustainably meet a growing world population’s food and energy needs. One of the ways to do so is by using agro-industry wastewater to cultivate microalgae. While the industrial production of microalgae requires large volumes of water, existing agro-industry processes generate large volumes of wastewater with eutrophicating nutrients and organic carbon that must be removed before recycling the water back into the environment. Coupling these two processes can benefit the flourishing microalgal industry, which requires water, and the agro-industry, which could gain extra revenue by converting a waste stream into a bioproduct. Microalgal biomass can be used to produce energy, nutritional biomass, and specialty products. However, there are challenges to establishing stable and circular processes, from microalgae selection and adaptation to pretreating and reclaiming energy from residues. This review discusses the potential of agro-industry residues for microalgal production, with a particular interest in the composition and the use of important primary (raw) and secondary (digestate) effluents generated in large volumes: sugarcane vinasse, palm oil mill effluent, cassava processing waster, abattoir wastewater, dairy processing wastewater, and aquaculture wastewater. It also overviews recent examples of microalgae production in residues and aspects of process integration and possible products, avoiding xenobiotics and heavy metal recycling. As virtually all agro-industries have boilers emitting CO₂ that microalgae can use, and many industries could benefit from anaerobic digestion to reclaim energy from the effluents before microalgal cultivation, the use of gaseous effluents is also discussed in the text. Full article

The concept of circularity is currently proposed to address key sustainability issues affecting and affected by livestock production. Through a desk study, this paper evaluates some feed sources that are being developed in The Netherlands as an alternative to current feeds, namely food waste; seaweed; and localized production and alternative plant-based feed sources. These feed categories are evaluated according to four circularity criteria. The first two criteria concern standard circularity principles aimed at both stopping and preventing environmental damage as well as a focus on natural resources use efficiency: (1) safeguard the health of ecosystems and (2) avoid the production of unnecessary products and use/recycle biomass effectively, as well as evaluating possible food–feed competition. In addition, two ‘people’ and ‘animal’ centred principles have been integrated: (3) fairness and accessibility and (4) animal health and wellbeing. The article concludes that people and animal centred principles are key to thinking of, developing, implementing, and evaluating circularity initiatives. Moreover, the article suggests that categories such as the local production of soya (approx. 132 ha) or seaweed (approx. 10–15 ha) are as yet irrelevant regarding production volumes within the Dutch context. However, some feed sources such as seaweed, insects, livestock leftovers produced at farms and abattoirs, and food waste might strengthen the transition towards more circular and sustainable practices. Full article

Ruminants, which have multi-compartmented stomachs, are adapted to digest cellulosic materials, which constitute the primary expense on ranches and dairies. Industrial byproducts can be repurposed for livestock diets to decrease these costs. Therefore, finding alternative feedstuffs may benefit the economics of livestock production. The goal of this project was to evaluate the variation in nutritive value of ruminal waste as a potential feedstuff. Twelve paunch samples were collected from individual cattle across multiple harvest dates at the Tarleton State University Meat Laboratory, Stephenville, TX. Samples were dried and assayed for dry matter (DM), crude protein (CP), sequential neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL), and physically-effective fiber (peNDF). Samples were subjected to batch-culture in vitro digestibility assays for the determination of digestibility coefficients. Mean NDF, ADF, ADL, CP and peNDF concentrations were 681, 399, 109, 150, and 387 g kg⁻¹ DM, respectively. Contribution to variance from sample for NDF, ADF, ADL, CP, and peNDF were 75.3, 41.9, 33.0, 51.2, and 71.3%, respectively. In vitro true digestibility (IVTD) and in vitro NDF digestibility (IVNDFD) were recorded as 462 and 216 g kg⁻¹ DM, respectively. Contribution to variation of sample for IVTD and IVNDFD were 31.0 and 30.7%, respectively. Results indicate that rumen waste harvested from abattoirs may be useful for sustainable livestock production, while reducing environmental threats posed by disposal, but the viability of the product is highly dependent on the source animal. For full viability of application in a sustainable system, a centralized receiving and compositing system may be useful for developing a consistent product. Full article

Wasting disease in small ruminants is frequently detected at slaughterhouses. The wasting disorder is manifested by the deterioration of the nutritional and physiological state of the animal indicated by thinness, emaciation, and cachexia. Evidence of emaciation and cachexia, alone, are pathological conditions leading to carcass condemnation during an inspection. Several diseases are associated with a wasting condition, including scrapie, pseudotuberculosis, tuberculosis, paratuberculosis, Maedi Visna, and tumor diseases. On the other hand, parasitic diseases, nutrition disorders, exposure or ingestion of toxins, metabolic conditions, inadequate nutrition due to poor teeth, or poor alimentary diet are conditions contributing to poor body condition. Classical and atypical scrapie is naturally occurring transmissible spongiform encephalopathies in small ruminants. The etiological agent for each one is prions. However, each of these scrapie types is epidemiologically, pathologically, and biochemically different. Though atypical scrapie occurs at low incidence, it is consistently prevalent in the small ruminant population. Hence, it is advisable to include differential diagnosis of this disease, from other possibilities, as a cause of wasting conditions detected during meat inspection at the abattoir. This manuscript is a review of the measures in force at the abattoir for scrapie control, focusing on the differential diagnosis of gross lesions related to wasting conditions detected in small ruminants during meat inspection. Full article

Organic wastes of rural slaughterhouses in developing countries comprise of blood and undigested rumen contents harboring infectious microbial pathogens and having impermissible BOD₅ and COD values. Previously we demonstrated valorization of blood and rumen contents through drying and conversion to an efficacious organic fertilizer which was free from infectious pathogens and heavy metals. Here we describe fabrication of a novel helical-ribbon mixer dryer for transition from the current small-scale household cooking to equipment-driven sustainable production. Blood and rumen digesta mixed in a 3:1 ratio, having initial moisture of 85%, were dried at 90–110 °C for 3–4 h to attain 15.6% final moisture-containing organic fertilizer. Energy consumption and moisture extraction rate were 49.4 MJ per batch and 18.9 kg h⁻¹ respectively. Using this method, small abattoir owners could emerge as multi-product producers to enhance earnings while farmers could source the fertilizer locally for organic farming. The two activities can be complementary to each other and become a sustainable circular economy model. We applied a spreadsheet-based model for calculation of cash flow, breakeven point and conducted financial cost–benefit analysis on the projected operation of the dryer. Fertilizer production parallel with the meat trade should be profitable for slaughterhouse owners and farmers apart from generating local employment opportunities. Full article

This work represents and reviews a compilation of investigations into improving anaerobic digestion performance of high-strength wastewater in the Australian Red Meat Processing industry. The industry produces significant quantities of organic-rich wastewater which requires treatment prior to release to the environment. Anaerobic lagoons are a cost-effective method of waste treatment where land availability is not an issue; however, the high fat load in the wastewater can negatively impact the anaerobic lagoon system and result in compromised anaerobic digestion performance. This paper will discuss the importance of upstream primary pre-treatment and review a series of investigations focused on optimising digester performance and improving fat biodegradability. These studies include: 1. the effect of temperature and mixing; 2. the influence of feedstock trace element composition and supplementation, and; 3. the potential benefit from pre-treatments such as chemical, thermobaric, thermochemical and bio-surfactant. This paper discusses the implications of these findings for covered anaerobic lagoon operation and provides recommendations to promote optimum digester performance and future opportunities in adopting alternate anaerobic digestion technology options. Finally, the paper provides recent trends toward the use of other waste streams for co-digestion and discusses this in terms of digester optimization and technology options. Full article

Vertebral osteomyelitis (VO) it is often a suppurative lesion that, in Portugal, represents the main cause of total condemnation of slaughtered finishing pigs. Based on the EU Meat Inspection legislation, meat from generalized VO cases presenting signs of pyemia should be declared unfit for human consumption. For that reason, the main objective of this study is to establish a classification scheme to differentiate between localized and generalized VO cases using macroscopic findings and validate it based on the presence of pyemia. To assist in, a combination of macroscopic characteristics of gross lesions (e.g., presence of pyaemia-related lesions (PRL), acute/chronic characteristics of VO) was used to create a classification scheme to differentiate between localized and generalized VO cases. The scheme was applied to 40 VO cases that had been totally condemned in an undifferentiated way. In those 40 cases, histopathological analysis was used to validate acute/chronic macro-criteria, and microbiological analysis was performed to identify the pyemia cases. From the 40 selected VO cases, 20 were macroscopically classified as chronic and 20 as acute. Cohen’s kappa coefficient (κ = 0.80; p < 0.001), revealed a substantial agreement between macroscopic and histopathology classification. Microbiological analyses identified 13 pyemia cases (13/40; 32.5%). Among those, 12 were macroscopically classified as acute, this association being highly significant (p < 0.001). By using the proposed VO classification scheme, 14 possible cases out of 40 could have been spared from total condemnation. This scheme can be used to harmonize the classification of VO and meat inspection decisions in Portuguese abattoirs. The output would lead to avoidance of unnecessary carcasses condemnation (food waste/economic losses), under an evidence-based approach, without compromising food safety and public health as demanded by the EU Meat Inspection legislation. Full article

Management of waste streams from abattoirs is a major challenge in developing countries. Harnessing these wastes as resources for the production of biogas and biofertilizer could contribute to curbing the environmental menace and to addressing the problems of energy and food deficits in Nigeria. However, large scale uptake of the technology is faced with techno-socio-economic and the lack of data required for effective investment decisions. In this study, the potential use of waste generated in the north central region of Nigerian abattoirs, representing approximately 12% of the land and 6% of the population, were evaluated for suitability for biogas and biofertilizer production. Data acquired from the study sites were used for computational estimation and integrated into strengths, weaknesses, opportunities, and threats (SWOT) analysis to give a detailed overview of the prospects and the limiting factors. The study revealed that high investment costs and public subsidies for fossil fuels are the key limiting factors while the prospects of tapping into the unexploited carbon markets and multiple socio-economic and environmental benefits favors investment. Public supports in the form of national policy reforms leading to intervention programs are required for progress. Full article

Meat processing plants generate a range of solid and liquid wastes, including manure, paunch solids, and biological solids from wastewater treatment. There is growing interest in alternative technologies for treating abattoir waste, including using insects to transform waste into high-value products. Black Soldier Fly (BSF) larvae may be a competitive source of digestible amino acids and, depending on the protein digestibility, can be used as a replacement for fish meal, soybean meal or cottonseed meal in livestock and aquaculture rations. The objective of this study was to evaluate the effect of using different substrates and substrate mixes from abattoir waste streams on the nutritional quality of BSF harvested at two growth stages (larvae and prepupae). Protein digestibility was evaluated using an adapted pepsin digestion. Averaged across all substrates, there was no difference between growth stages in total protein content (43.7%). However, protein digestibility was higher for larvae (86.5%) than for prepupae (65.1%). The substrate used greatly influenced the nutritional composition of BSF. Prepupae protein content varied from 42 to 48% and protein digestibility varied from 42 to 80%, according to the substrate. Variation in larvae across substrates was greater than prepupae for protein content (34% to 53%) but much lower for digestibility (80% to 91%). Both substrate and growth stage altered the mineral composition of BSF prepupae and larvae. Iron levels varied from 79 (paunch) to 453 mg/kg DM (substrate containing blood), illustrating the plasticity of BSF. In conclusion, BSF can be used to transform abattoir waste into high-value products. Full article

The use of the black soldier fly (BSF: Hermetia illucens) as a means of upstreaming waste has enjoyed increasing research the past few years. One of the uses of the resultant larvae is as animal feed, with particular success achieved when fed to mono-gastric animals. Most of the research has been on the use of BSF as feed in poultry and fish species. In poultry, larvae were produced on abattoir waste, kitchen waste or faecal matter (human and animal manure). The insects were grown until harvest as larvae, pre-pupae or pupae. The post-harvest processing included freezing, drying and/or milling. Where the poultry were fed Iso-nitrogenous/Iso-energetic diets containing various proportions of BSF, no differences in production performance or carcass yields (breast-, thigh-yields) were found. As pertaining to meat quality, no differences for initial pH or ultimate pH of the meat were noted. Differences for breast colour measurements were found; larvae fed chicken breast meat was generally lighter and redder whilst results on the breasts’ water binding capacity was inconclusive. For sensory attributes, no differences were observed except for juiciness and sustained juiciness. Sometimes a metallic flavour was noted, particularly on larvae fed on abattoir wastes. Manipulating the larvae’s diet as a strategy to change the chemical composition of the poultry has focused on attempts to change the fatty acid profiles and yielded mixed results; irrespective of the fatty acid profile, the fat of BSF larvae contains large amounts of lauric acid; known to have profound antiviral and antibacterial activity. Full article

Abattoirs are potentially a significant source of greenhouse gas (GHG) methane (CH₄) and nitrous oxide (N₂O) emissions. Measurements were conducted in a beef cattle abattoir located in Bamenda, Cameroon, to characterise waste production and quantify GHG emissions. A male and female cattle were randomly selected on each day for waste measurement over a period of two weeks. Waste from each cattle was quantified by collecting all the intestinal/stomach contents after slaughtering and determining the mass of dry matter (DM) and volatile solids (VS). Emissions from the outdoor solid waste storage heap was measured using flux chambers. The average cattle weight was 420 kg and the average intestinal/stomach waste was 37 ± 6 kg cattle⁻¹, half of which was dumped outdoor in a heap, while the rest was discarded with wastewater into a stream. The DM produced was 4.19 ± 0.85 kg cattle⁻¹, representing 11% of the wastes, and the VS produced was 3.42 ± 0.82 kg cattle⁻¹. The average ratio of waste DM to cattle weight was 1.0%, while the ratio of waste VS to cattle weight was 0.8%. Modelled CH₄ emissions from the total waste was estimated at 37.84 ± 8 g CH₄ cattle⁻¹ with a range of 27.57–56.03 g CH₄ cattle⁻¹. Measured GHG emission from the outdoor heap was 5.89 ± 4.78 mg CH₄ m⁻² min⁻¹, 0.137 ± 0.151 mg N₂O m⁻² min⁻¹, and 95 ± 83 mg CO₂ m⁻² min⁻¹. The total GHG (CH₄ + N₂O) emission rate was 229 mg CO₂e m⁻² min⁻¹, indicating that CH₄ contributes 82% of the total GHG. Improved waste management strategies, such as anaerobic digestion for biogas production or using covers over waste heaps, would help abattoirs mitigate GHG emissions. Full article