Journal articles on the topic 'Animal manure feedstocks'

Animal manure represents a major source of renewable energy that can be converted into biogas using anaerobic digestion. In order to most efficiently utilize this resource, it can be co-digested with energy dense, high biomethanation potential feedstocks such as energy crops. However, such feedstocks typically require pretreatments which are not feasible for small-scale facilities. We investigated the use of single-stage and the sequential co-digestion of comminuted but otherwise non-pretreated Salix with animal manure, and further investigated the effects of coppicing frequency and clone choice on biomethanation potential and the area requirements for a typical Swedish farm-scale anaerobic digester using Salix and manure as feedstock. In comparison with conventional single-stage digestion, sequential digestion increased the volumetric and specific methane production by 57% to 577 NmL L−1 d−1 and 192 NmL (g volatile solids (VS))−1, respectively. Biomethanation potential was the highest for the two-year-old shoots, although gains in biomass productivity suggest that every-third-year coppicing may be a better strategy for supplying Salix feedstock for anaerobic digestion. The biomethane production performance of the sequential digestion of minimally pretreated Salix mirrors that of hydrothermally pretreated hardwoods and may provide an option where such pretreatments are not feasible.

Magnetic nanobiochar (MNBC) is a sort of nanobiochar that has been enhanced with magnetic qualities. MNBC is made from a variety of feedstocks, including wood chips, agricultural waste, municipal sludge, animal manure, and other organic waste. These feedstocks are pyrolyzed at various temperatures to produce biochar, which is then mixed with magnetic precursors to create MNBC. Crystallinity, high porosity, specific surface area, and great catalytic activity are a few of the dynamic properties of MNBC. The major purpose of this review paper is to characterize MNBC, using the various biochar synthesis methods and how bulk biochar is converted into MNBC with their high-value applications discussed here.

Biogas is expected to play a crucial role in achieving the energy targets set by the European Union. Biogas, which mainly comprises methane and carbon dioxide, is produced in an anaerobic reactor, which transforms biomass into biogas. A consortium of anaerobic bacteria and archaea produces biogas during the anaerobic digestion (AD) of various types of feedstocks, such as animal slurries, energy crops, and agricultural residues. A biogas-fed gas turbine-generator and steam generator produce heat and power. In this study, a combined heat and power installation is studied. The biogas-based power plant treating cow manure, grass straw, and sugar beet pulp was examined using the software SuperPro Designer, and the obtained economic reports are evaluated. From the results, subsidy for electricity does not change the feasibility of the plants in case that cow manure or sugar beet pulp are used as feedstocks. The net present value (NPV) of biogas plants treating cow manure and sugar beet pulp was negative and the subsidy is not sufficient to make profitable these cases. The biogas power plant treating straw showed a positive net present value even without subsidy, which means that it is more desirable to invest in a plant that produces electricity and digestate from grass straw.

Agricultural biogas plants are increasingly being used in Europe as an alternative source of energy. To optimize the sizing and operation of existing or future biogas plants, a better knowledge of different feedstocks is needed. Our aim is to characterize 132 common agricultural feedstocks in terms of their chemical composition (proteins, fibers, elemental analysis, etc.) and biochemical methane potential shared in five families: agro-industrial products, silage and energy crops, lignocellulosic biomass, manure, and slurries. Among the families investigated, manures and slurries exhibited the highest ash and protein contents (10.3–13.7% DM). High variabilities in C/N were observed among the various families (19.5% DM for slurries and 131.7% DM for lignocellulosic biomass). Methane potentials have been reported to range from 63 Nm3 CH4/t VS (green waste) to 551 Nm3 CH4/t VS (duck slurry), with a mean value of 284 Nm3 CH4/t VS. In terms of biodegradability, lower values of 52% and 57% were reported for lignocelluloses biomasses and manures, respectively, due to their high fiber content, especially lignin. By contrast, animal slurries, silage, and energy crops exhibited a higher biodegradability of 70%. This database will be useful for project owners during the pre-study phases and during the operation of future agricultural biogas plants.

In this study the response of biogas-producing microbiomes to a profound feedstock change was investigated. The microbiomes were adapted to the digestion of either 100% sugar beet, maize silage, or of the silages with elevated amounts of total ammonium nitrogen (TAN) by adding ammonium carbonate or animal manure. The feedstock exchange resulted in a short-range decrease or increase in the biogas yields according to the level of chemical feedstock complexity. Fifteen taxa were found in all reactors and can be considered as generalists. Thirteen taxa were detected in the reactors operated with low TAN and six in the reactors with high TAN concentration. Taxa assigned to the phylum Bacteroidetes and to the order Spirochaetales increased with the exchange to sugar beet silage, indicating an affinity to easily degradable compounds. The recorded TAN-sensitive taxa (phylum Cloacimonetes) showed no specific affinity to maize or sugar beet silage. The archaeal community remained unchanged. The reported findings showed a smooth adaptation of the microbial communities, without a profound negative impact on the overall biogas production indicating that the two feedstocks, sugar beet and maize silage, potentially do not contain chemical compounds that are difficult to handle during anaerobic digestion.

Uranium (U) and fluoride (F−) are the major global geogenic contaminants in aquifers and pose serious health issues. Biochar, a potential adsorbent, has been widely applied to remediate geogenic and anthropogenic contaminants. However, there is a lack of research progress in understanding the role of different feedstock types, modifications, adsorption mechanisms on physico-chemical properties of biochar, and factors affecting the adsorption of U and F− from aqueous solution. To fill this lacuna, the present review gives insight into the U and F− removal from aqueous solution utilizing biochar from various feedstocks. Feedstock type, pyrolysis temperature, modifications, solution pH, surface area, and surface-charge-influenced biochar adsorption capacities have been discussed in detail. Major feedstock types that facilitated U and F− adsorption were crop residues/agricultural waste, softwood, grasses, and animal manure. Low-to-medium pyrolyzing temperature yielded better biochar properties for U and F− adsorption. Effective modification techniques were mainly acidic and magnetic for U adsorption, while metal oxides, hydroxides, alkali, and magnetic modification were favourable for F− adsorption. The major mechanisms of U adsorption were an electrostatic attraction and surface complexation, while for F− adsorption, the major mechanisms were ion exchange and electrostatic attraction. Lastly, the limitations and challenges of using biochar have also been discussed.

The looming climate and energy crises, exacerbated by increased waste generation, are driving research and development of sustainable resource management systems. Research suggests that organic materials, such as food waste, grass, and manure, have potential for biotransformation into a range of products, including: high-value volatile fatty acids (VFAs); various carboxylic acids; bioenergy; and bioplastics. Valorizing these organic residues would additionally reduce the increasing burden on waste management systems. Here, we review the valorization potential of various sustainably sourced feedstocks, particularly food wastes and agricultural and animal residues. Such feedstocks are often micro-organism-rich and well-suited to mixed culture fermentations. Additionally, we touch on the technologies, mainly biological systems including anaerobic digestion, that are being developed for this purpose. In particular, we provide a synthesis of VFA recovery techniques, which remain a significant technological barrier. Furthermore, we highlight a range of challenges and opportunities which will continue to drive research and discovery within the field. Analysis of the literature reveals growing interest in the development of a circular bioeconomy, built upon a biorefinery framework, which utilizes biogenic VFAs for chemical, material, and energy applications.

Recent studies have proposed usage of biochar as a substrate amendment in green infrastructure, such as green roofs and bio-filtration units. However, understanding of the variation in physio-chemical properties of biochar due to the production process and feedstock is still lacking. The present study investigated the effects of pyrolysis temperature and feedstocks on the hygroscopic water content and physio-chemical properties of biochar. Biochars were produced from three feedstock types, invasive vegetation (i.e., water hyacinth), non-invasive vegetation (i.e., wood) and one animal waste (i.e., chicken manure). Biochar was produced at two different pyrolysis temperatures (i.e., 300 °C and 600 °C). Scanning electron microscopy + energy dispersive spectrometry (SEM + EDS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) were performed on all samples to analyze the surface morphology, pore size, element content, functional groups, and chemical bonds. Relative humidity was adjusted to reflect the biochar’s hygroscopic property by measuring the maximum moisture content at the sample equilibrium state. The characterization reveals that the lowest carbon content (42.78%) was found at 300 °C for water hyacinth biochar (WHB). The highest carbon content (92.14%) was found at 600 °C for wood biochar (WB). As the pyrolysis temperature increased, the mean pore volume (from 0.03 to 0.18 cm3/g) and diameter (from 8.40 to 10.33 nm) of the WHB increased. However, the pore diameter of chicken manure (CB) decreased (from 9.23 nm to 7.53 nm) under an increase in pyrolysis temperature. For a given pyrolysis temperature, the hygroscopicity of WHB was highest among all biochars. With an increase in pyrolysis temperature, the hygroscopicity of biochars changed differently. The hygroscopicity of WHB decreased from 82.41% to 44.33% with an increase of pyrolysis temperature. However, the hygroscopicity of CMB and WB remained unchanged. This study suggests that production process of biochars need to be considered for appropriate selection as substrate material in green infrastructure. Further, it promotes the establishment of commercial production of biochar for usage in green infrastructure.

Biofuels are sustainable alternatives to fossil fuels because of their renewable and low-cost raw materials, environmentally friendly conversion technologies and low emissions upon combustion. In addition, biofuels can also be upgraded to enhance their fuel properties for wide applicability in power infrastructures. Biofuels can be produced from a wide variety of biomasses through thermochemical and biological conversion processes. This article provides insights into the fundamental and applied concepts of thermochemical conversion methods such as torrefaction, pyrolysis, liquefaction, gasification and transesterification. It is important to understand the physicochemical attributes of biomass resources to ascertain their potential for biofuel production. Hence, the composition and properties of different biomass resources such as lignocellulosic feedstocks, oilseed crops, municipal solid waste, food waste and animal manure have been discussed. The properties of different biofuels such as biochar, bio-oil, bio-crude oil, syngas and biodiesel have been described. The article concludes with an analysis of the strength, weaknesses, opportunities and threats of the thermochemical conversion technologies to understand their scale-up applications and commercialization.

Bangladesh has endured a significant power crisis as its economy grows. Hence, it is crucial to investigate the 40% expansion of renewable energy to attain the 2041 renewable energy goal as delineated by the government of Bangladesh. The study explores the current agricultural waste situation in rural areas of the Dinajpur District to propose a feasible alternative and integrated waste management system to meet the energy policy targets for animal waste and crop residues. It analyzed the spatial distribution of feedstocks, identified the optimal sites for the locations of biogas plants based on socioeconomic and environmental criteria and geographic information, and evaluated biogas production to satisfy electricity demand using geographic information system (GIS) suitability analysis and hotspot analysis by proposing six different scenarios. The results show that 2.81 million tons of total agricultural residues are sufficient to produce 11.31 million m3 per year of biogas in the study area. Furthermore, it is found that 21 biogas-based power plants using cattle manure and rice straw are spatially and technically feasible to produce 6389.14 kW of electrical energy per year, which meets 5.73% of the demand of the district in 2019. From the 6 proposed scenarios, number 4 can produce the maximum electricity, 3047.41 kW/year. The findings support the target of achieving a clean, green, sustainable energy system in Bangladesh while improving agricultural residue management. Estimating substrate availability and location is one of the first steps in promoting biogas-based energy from cattle manure and rice straw, which demands comprehensive technical, economic, and social policy reforms. Moreover, bioenergy expansion in Dinajpur District via biogasification represents a commitment to long-term investments in rural areas of Bangladesh.

HighlightsAquatic vegetation-based nutrient recovery offers an alternate approach for treating agricultural wastewater.Microalgae and duckweed can upcycle waste nutrients into valuable bio-based products.Producing feed, fertilizer, and fuel from manure-grown aquatic vegetation promotes a circular N-bioeconomy.Abstract. The massive amounts of nutrients that are currently released into the environment as waste have the potential to be recovered and transformed from a liability into an asset through photosynthesis, industry insight, and ecologically informed engineering design aimed at circularity. Fast-growing aquatic plant-like vegetation such as microalgae and duckweed have the capacity to enable local communities to simultaneously treat their own polluted water and retain nutrients that underlie the productivity of modern agriculture. Not only are they highly effective at upcycling waste nutrients into protein-rich biomass, microalgae and duckweed also offer excellent opportunities to substitute or complement conventional synthetic fertilizers, feedstocks in biorefineries, and livestock feed while simultaneously reducing the energy consumption and greenhouse gas emissions that would otherwise be required for their production and transport to farms. Integrated systems growing microalgae or duckweed on manure or agricultural runoff, and subsequent reuse of the harvested biomass to produce animal feed, soil amendments, and biofuels, present a sustainable approach to advancing circularity in agricultural systems. This article provides a review of past efforts toward advancing the circular nitrogen bioeconomy using microalgae- and duckweed-based technologies to treat, recover, and upcycle nutrients from agricultural waste. The majority of the work with microalgae- and duckweed-based wastewater treatment has been concentrated on municipal and industrial effluents, with <50% of studies focusing on agricultural wastewater. In terms of scale, more than 91% of the microalgae-based studies and 58% of the duckweed-based studies were conducted at laboratory-scale. While the range of nutrient removals achieved using these technologies depends on various factors such as species, light, and media concentrations, 65% to 100% of total N, 82% to 100% of total P, 98% to 100% of NO3-, and 96% to 100% of NH3/NH4+ can be removed by treating wastewater with microalgae. For duckweed, removals of 75% to 98% total N, 81% to 93% total P, 72% to 98% NH3/NH4+, and 57% to 92% NO3- have been reported. Operating conditions such as hydraulic retention time, pH, temperature, and the presence of toxic nutrient levels and competing species in the media should be given due consideration when designing these systems to yield optimum benefits. In addition to in-depth studies and scientific advancements, policies encouraging supply chain development, market penetration, and consumer acceptance of these technologies are vitally needed to overcome challenges and to yield substantial socio-economic and environmental benefits from microalgae- and duckweed-based agricultural wastewater treatment. Keywords: Circular bioeconomy, Duckweed, Manure treatment, Microalgae, Nitrogen, Nutrient recycling, Wastewater treatment.

Growing animal production results in a significant amount of waste, composed of manure, bedding, feed, feathers, etc., whose safe and cost-effective disposal becomes a troublesome challenge. The literature review points out that the higher heating value (HHV) of animal-origin waste reaches 19 MJ/kg (dry basis), which positions it as a promising renewable energy source. Various paths of energy recovery were investigated in the literature, but the thermal processes, particularly combustion and co-combustion, were indicated as the most effective from both technical and environmental points of view. The presented study reviews the fuel characteristics, possible combustion-related challenges, and ash disposal routes of the most popular animal-origin waste: poultry litter and cow (cattle) manure with a slight sight on piggery (swine) manure. When considering animal-origin feedstock as fuel, usually only animal species is given (poultry, cattle, etc.). However, according to the analyzed literature data, this is not sufficient information. Several more factors crucially influence the fuel and ash properties of animal waste and the most vital are: the housing system, type of bedding, and farming style. Animal litter is considered a “difficult” fuel, nevertheless, it does not always cause combustion-related problems. Some analyzed feedstock feature low chlorine concentrations and high ash melting temperatures, which makes them combustion-friendly.

The bioeconomy can play a critical role in helping countries to find alternative sustainable sources of products and energy. Countries with diverse terrestrial and marine ecosystems will see diverging feedstock opportunities to develop these new value chains. Understanding the sources, composition, and regional availability of these biomass feedstocks is an essential first step in developing new sustainable bio-based value chains. In this paper, an assessment and analysis of regional biomass availability was conducted in the diverse regions of Andalusia and Ireland using a bioresource mapping model. The model provides regional stakeholders with a first glance at the regional opportunities with regards to feedstock availability and an estimate of the transportation costs associated with moving the feedstock to a different modelled location/region for the envisioned biorefinery plant. The analysis found that there were more than 30 million tonnes of (wet weight) biomass arisings from Ireland (84,000 km2) with only around 4.8 million tonnes from the Andalusian region (87,000 km2). The study found that Cork in Ireland stood out as the main contributor of biomass feedstock in the Irish region, with animal manures making the largest contribution. Meanwhile, the areas of Almería, Jaén, and Córdoba were the main contributors of biomass in the Andalusia region, with olive residues identified as the most abundant biomass resource. This analysis also found that, while considerable feedstock divergence existed within the regions, the mapping model could act as an effective tool for collecting and interpreting the regional data on a transnational basis.

In this study sustainable valorization of cattle manure, recycled polyester, and their blend (1:1 wt.%) were examined by the thermogravimetric analysis (TGA) method. Pyrolysis tests were performed at 10, 30, and 50 °C/min heating rate from room temperature to 1000 °C under a nitrogen environment with a flow of 100 cm3/min. Kinetics of decomposition were analyzed by using Flynn–Wall–Ozawa (FWO) method. Based on activation energies and conversion points, a single region was established for recycled polyester while three regions of pyrolysis were obtained for cattle manure and their blend. Comparison between experimental and theoretical profiles indicated synergistic interactions during co-pyrolysis in the high temperature region. The apparent activation energies calculated by FWO method for cattle manure, recycled polyester. and their blend were 194.62, 254.22 and 227.21 kJ/mol, respectively. Kinetics and thermodynamic parameters, including E, ΔH, ΔG, and ΔS, have shown that cattle manure and recycled polyester blend is a remarkable feedstock for bioenergy.

SUMMARYThere is a very significant, cost effective greenhouse gas (GHG) mitigation potential in agriculture. The annual mitigation potential in agriculture is estimated to be 4200, 2600 and 1600 Mt CO2 equiv/yr at C prices of 100, 50 and 20 US$/t CO2 equiv, respectively. The value of GHG mitigated each year is equivalent to 420 000, 130 000 and 32 000 million US$/yr for C prices of 100, 50 and 20 US$/t CO2 equiv, respectively. From both the mitigation and economic perspectives, we cannot afford to miss out on this mitigation potential.The challenge of agriculture within the climate change context is two-fold, both to reduce emissions and to adapt to a changing and more variable climate. The primary aim of the mitigation options is to reduce emissions of methane or nitrous oxide or to increase soil carbon storage. All the mitigation options, therefore, affect the carbon and/or nitrogen cycle of the agroecosystem in some way. This often not only affects the GHG emissions but also the soil properties and nutrient cycling. Adaptation to increased variability of temperature and rainfall involves increasing the resilience of the production systems. This may be done by improving soil water holding capacities through adding crop residues and manure to arable soils or by adding diversity to the crop rotations.Though some mitigation measures may have negative impacts on the adaptive capacity of farming systems, most categories of adaptation options for climate change have positive impacts on mitigation. These include: (1) measures that reduce soil erosion, (2) measures that reduce leaching of nitrogen and phosphorus, (3) measures for conserving soil moisture, (4) increasing the diversity of crop rotations by choices of species or varieties, (5) modification of microclimate to reduce temperature extremes and provide shelter, (6) land use change involving abandonment or extensification of existing agricultural land, or avoidance of the cultivation of new land. These adaptation measures will in general, if properly applied, reduce GHG emissions, by improving nitrogen use efficiencies and improving soil carbon storage.There appears to be a large potential for synergies between mitigation and adaptation within agriculture. This needs to be incorporated into economic analyses of the mitigation costs. The inter-linkages between mitigation and adaptation are, however, not very well explored and further studies are warranted to better quantify short- and long-term effects on suitability for mitigation and adaptation to climate change. In order to realize the full potential for agriculture in a climate change context, new agricultural production systems need to be developed that integrate bioenergy and food and feed production systems. This may possibly be obtained with perennial crops having low-environmental impacts, and deliver feedstocks for biorefineries for the production of biofuels, biomaterials and feed for livestock.

Biochars made from animal manure feedstock appear to be a potential phosphorus (P) fertilizer source. Five different manure-derived biochars, pyrolyzed at two different temperatures (350 and 700 °C) were assessed for their potential as a P fertilizer for cotton (Gossypium hirsutum L.). A greenhouse study was conducted using a Uchee sand soil. Biochar was applied at rates that provided 40 mg P kg-1 soil. Four rates of calcium phosphate (0, 20, 40, and 60 mg P kg-1 soil) were included in the study. Cotton plants were allowed to grow to 60 days post-emergence at which point leaves and stems were harvested for physical and chemical analysis. The experiment was conducted twice. Results demonstrated that biochar worked as a P fertilizer and that feedstock choice combined with biochar processing temperature accounted for a majority of the differences among the 10 treatments tested. When applied at standard P fertilization rates, manure-derived biochars perform equally to calcium phosphate fertilizer.

Jamaica is heavily dependent on fossil fuels to meet its energy demand and is currently seeking to reduce consumption. Accordingly, it is essential to investigate the expansion of renewable energy systems to achieve its 2030 renewable energy goal of 50%, with 70% diversification in energy types, as outlined in the National Energy Policy 2009–2030. This study explores biogas feasibility in Jamaica and discusses the potential for electricity generation from combinations of dairy cow and Swine feces with sugarcane bagasse. The study’s primary purpose is to assess the feasibility of biogas production from livestock manure and sugarcane bagasse for electricity generation and manure treatment. Findings reveal that biogas anaerobic digestion and the co-digestion of different varieties of animal manure with sugarcane bagasse can generate up to 122,607.68 MWh or 2.49% of Jamaica’s total electrical energy generation in 2019. The findings indicate a high potential for the installation of community-based plants. Moreover, considering all scenarios and the remaining feedstock, potential electrical energy increases to 222,868.60 MWh (4.53% of total energy generation). This power may be fed to the electrical grid network or consumed by local producers. In addition, electric power generation from animal manure and sugarcane bagasse is feasible with improved technical capability and human development. Additionally, anaerobic digestion and co-digestion of sugarcane bagasse plus animal manure offer an excellent solution to mitigate climate change.

Previous studies for removal of ammonium from wastewater were mainly conducted using biochars produced from agricultural residue. Feedstock type (agricultural residue, wood, animal waste, and aquatic waste), as well as pyrolysis temperature, can significantly influence biochar properties and hence its adsorption capacity. Such studies are useful in decision making for selecting biochar depending on feedstock availability and pyrolysis temperature. This study aims to explore the effects of different types of biochar (laboratory prepared novel water hyacinth and algae biochar, conventional cedar wood, rice straw, and pig manure biochar) on the adsorption kinetics for ammonium removal from wastewater. The adsorption kinetics of biochars were compared to that of commercially available clinoptilolite and interpreted with their respective physicochemical properties (SEM, FTIR, XRD). Batch tests were performed to evaluate the effects of biochars on adsorption of ammonium nitrogen at different concentrations (10 mg/L and 100 mg/L). The tests reveal that clinoptilolite has the highest adsorption capacity. Among biochars, pig manure (animal based) biochar has a higher adsorption capacity in comparison to conventional agricultural residues based biochars. The capacity of pig manure biochar under highly concentrated ammonium solution (100 mg/L) is merely 20% lower than that of clinoptilolite. Both water hyacinth and algae biochar produced at higher temperature (600 °C) show higher sorption rate and capacity (depending on the initial concentration of ammonium) for ammonium in comparison to that produced at a lower temperature (300 °C). This is likely due to an increase in porosity at higher temperatures of pyrolysis.

The long-term application of manures in watersheds with dense animal production has increased soil phosphorus (P) concentration, exceeding plant and soil assimilative capacities. The P accumulated in soils that are heavily manured and contain excess extractable soil P concentrations is known as legacy P. Runoff and leaching can transport legacy P to ground water and surface water bodies, contributing to water quality impairment and environmental pollution, such as eutrophication. This review article analyzes and discusses current and innovative management practices for soil legacy P. Specifically, we address the use of biochar as an emerging novel technology that reduces P movement and bioavailability in legacy P soils. We illustrate that properties of biochar can be affected by pyrolysis temperature and by various activating chemical compounds and by-products. Our approach consists of engineering biochars, using an activation process on poultry litter feedstock before pyrolysis to enhance the binding or precipitation of legacy P. Finally, this review article describes previous examples of biochar activation and offers new approaches to the production of biochars with enhanced P sorption capabilities.

Methane production characteristics of anaerobic co-digestion of pig manure (PM) and fermented liquid feed (FLF) were investigated in a continuous digester under mesophilic conditions. The experiment followed three phases. PM alone was digested in phase I. In phases II and III, PM and FLF were mixed in a ratio of 95:5 and 90:10 (% v/v), respectively. The specific methane yields (SMYs) during phases I, II, and III were 238, 278, and 326.8 mLCH4·gVS−1-added, respectively. It was due to the effect of balancing the feedstock carbon-to-nitrogen ratio by adding FLF. This improvement can also be attributed to the readily biodegradable compounds in the FLF. The higher SMY obtained in this study showed a positive synergistic effect in the anaerobic co-digestion of PM and FLF. The results also indicate that adding the FLF positively affected and maintained a constant pH level, avoiding volatile fatty acid accumulation and ammonia inhibition in the anaerobic digestion (AD). Thus, this study provides valuable information regarding the usage of unused or wasted FLF as a co-substrate for the practical AD of PM. The production of fermented liquid additives such as FLF to improve the methane production from the AD of PM is a potential novel alternative to food waste recycling in Japan, besides compost and animal feeding.

Biogas production through anaerobic digestion is a well-established practice worldwide combining waste treatment and energy production at the same time. One of the challenges of this technology is to increase the yield of biogas production and secure the disposal of the effluent of anaerobic reactors. It is well known that various organic residues such as cheese whey, olive mill wastewater, as well as food waste from hotel units, could be combined with other materials (animal manures, sewage sludge, etc.) in order to increase biogas production through co-digestion. However, their high seasonal variation and high transport costs is a barrier for their use. Solar drying process can be a very attractive technology for volume reduction in order to decrease the storage and the transportation cost. Moreover using solar energy may well be an alternative solution for reduction of drying process costs. In this study, co-digestion of pig manure (PM) and cow manure (CM) with solar dried mixture of food waste (FW) and olive mill wastewater (OMW), named as biobooster, was studied in an attempt to improve biogas production of existing on—farms plants which co-digest manure with other farm waste. The effect of biobooster in biogas production was investigated using three lab-scale continuous stirred-tank reactors (CSTR) (3 L working volume) (D1–D3) under mesophilic conditions (37 ± 2 °C) with a hydraulic retention time of 20 days. Initially, all reactors were inoculated with anaerobic sludge originating from sewage treatment plant of the city of Heraklion, and contained 19.6 g/L TS, 10.8 g/L VS and 17.5 g/L COD. Three types of influent feedstock were utilized: D1: PM (95%) + CM (5%) (VSin = 33.58 ± 4.51 g/L), D2: PM (95%) + CM (5%) + Biobooster (1%) (VSin = 41.07 ± 7.16 g/L), D3: PM (100%) + Biobooster (1%) (VSin = 8.48 ± 0.87 g/L). The experiments showed that the addition of biobooster to pig and cow manure significantly increased biogas production by nearly 65% as value of 662.75 ± 172.50 mL/l/d compared to that with pig and cow manure alone (402.60 ± 131.89 mL/l/d). The biogas production in D3 reactor was 242.50 ± 56.82 mL/l/d. This work suggests that methane can be improved very efficiently by adding a small portion (20% increase of VS) of dried agro-industrial by-products in the inlet of digesters of existing on—farms plants.

A major problem in the modern world is the overuse of fossil resources. The use of such resources and of that amount contribute negatively to the environment we live in. Fossil resources should be replaced with renewable ones. That way, less impact would be done to the environment. Renewable resources would greatly contribute to a healthy sustainable future. Latvia currently ranks seventh on the number of biogas plants per 1 million per capita (27) and is searching for new ways and opportunities to switch from the production of electricity to biomethane. Thus, in this study, a mathematical approach for the calculations of biomethane potentials and emissions of different feedstocks under the anaerobic digestion principle was studied. Databases were searched for the factual numbers of livestock animals, as well as processed sludge, and average food waste. RED II and JEC Well-To-Wheels report v5 were analyzed for data on emission factors and future obligations. Out of combined biomethane potentials of different feedstocks, livestock manure’s potential share was 91%, of which 61% is dairy cow manure. The overall biomethane potential in Latvia is 2.21 to 4.28 PJ. Replacing fossil fuels with biomethane in the transport sector could lower the overall CO2-eq emissions by 12.47–23.86% or 0.4–0.8 million tonnes.

(1) Background: The continuously increasing demand for renewable energy sources renders anaerobic digestion as one of the most promising technologies for renewable energy production. Due to the animal production intensification, manure is being used as the primary feedstock for most biogas plants. Their economical profitable operation, however, relies on increasing the methane yield from the solid fraction of manure, which is not so easily degradable. The solid fraction after anaerobic digestion, the so-called digested fibers, consists mainly of hardly biodegradable material and comes at a lower mass per unit volume of manure compared to the solid fraction before anaerobic digestion. Therefore, investigation on how to increase the biodegradability of digested fibers is very relevant. So far, Aqueous Ammonia Soaking (AAS), has been successfully applied on digested fibers separated from the effluent of a manure-fed, full-scale anaerobic digester to enhance their methane productivity in batch experiments. (2) Methods: In the present study, continuous experiments at a mesophilic (38 °C) CSTR-type anaerobic digester fed with swine manure first and a mixture of manure with AAS-treated digested fibers in the sequel, were performed. Anaerobic Digestion Model 1 (ADM1) previously fitted on manure fed digester was used in order to assess the effect of the addition of AAS-pre-treated digested manure fibers on the kinetics of anaerobic digestion process. (3) Results and Conclusions: The methane yield of AAS-treated digested fibers under continuous operation was 49–68% higher than that calculated in batch experiments in the past. It was found that AAS treatment had a profound effect mainly on the disintegration/hydrolysis rate of particulate carbohydrates. Comparison of the data obtained in the present study with the data obtained with AAS-pre-treated raw manure fibers in the past revealed that hydrolysis kinetics after AAS pre-treatment were similar for both types of biomasses.

Abstract Hermetia illucens L. (the black soldier fly) has received increased attention because of its great potential in converting organic waste into a renewable resource. The prepupae have high proportions of proteins and fats and can serve as feedstuff for livestock and as feedstock for biodiesel production. With the goal to upgrade the conversion of low-value organic wastes into high-value proteins and fat on a large scale, the effects of the feedstuffs food waste, pig manure, chicken manure, and cow dung on the reproductive potential and nutrient composition of H. illucens were evaluated. The intrinsic rate of increase of H. illucens fed food waste (0.1249 d−1) was significantly greater than the rate of those fed pig manure (0.1167 d−1), chicken manure (0.1154 d−1), and cow dung (0.1049 d−1). The ash content of H. illucens fed food waste (30.8 g·kg−1 lyophilized prepupa matter (LPM)) was significantly lower than that of those fed chicken manure (37.6 g·kg−1 LPM) and cow dung (49.5 g·kg−1 LPM). The contents of crude fat, 372.4 g·kg−1 LPM, and protein, 436.9 g·kg−1 LPM, in prepupae fed food waste were the highest among the four treatments. The reproductive performance and prepupal nutrient composition indicated that food waste was the most suitable feed for H. illucens. The results from this study further demonstrate that the prepupae of H. illucens have great potential for use as a protein and fat source in animal feeds and as biodiesel material.

Purpose Bioenergy as a renewable energy type is found as a promising method to replace non-renewable energy. Anaerobic co-digestion, in which the microorganisms of two or more substrates break into biodegradable materials without oxygen, and fermentation, in which substances break into a simpler form in the presence of microorganisms and some bacteria, are the two frequently used methods that are were applied in this work. Design/methodology/approach A farmland currently being used for farming was selected, and the bioenergy potential of the farmland was evaluated by using the aforementioned two methods. In this work, segregated municipal wastes which were collected from nearby areas and animal manure were used as feedstock for anaerobic co-digestion, whereas wheat straw obtained from the farmland was used as feedstock for fermentation. Findings The total input energy required for the digestion systems and the collection of the feedstock products from the growth to the harvest phases was calculated. Thereafter, the generated output energy was calculated to obtain an energy balance of the techniques. All the processes were taken into account during the prediction of the cost of the given power plant. The power output capacity of the farmland was 245 MW with a total cost of $540,200. Research limitations/implications Because of the chosen research approach, the research results may lack generalisability. Therefore, researchers are encouraged to test the proposed propositions further. Originality/value The result proves that the two methods were applicable and feasible to replace for the 200 ha farmland.

Insect biomass shows promise as an alternative animal feedstuff with a low climate effect. Industrial insect rearing generates residual materials, such as feed remains and insect excrements, so-called insect frass, which exhibits a high organic content. Commonly, these residues are utilized as soil amendment. Information on the suitability of these residues for biogas production is rather scarce. The energetic utilization of insect frass as feedstock for anaerobic digestion (AD) would allow for the simultaneous residue material reduction and bioenergy production. Additionally, synergies in heat management could arise using the exhaust heat of the biogas plant in the insect farming process. In laboratory-scale anaerobic digestion trials, the specific methane yield (SMY) of six different insect frass samples from black soldier fly (Hermetia) rearing were tested in batch biochemical methane potential (BMP) tests. Further, semi continuous anaerobic digestion trials on a lab scale using continuously stirred tank reactors (CSTRs) were carried out with Hermetia insect frass from a pilot plant operation in order to determine the digestibility and process stability of the AD process. The BMP results showed SMY values of the different insect frass samples ranging from 201 ± 9 to 287 ± 37 mL/gVS that are similar to those of other animal excrements, such as cow or pig manure already been used as feedstock in agricultural biogas plants. Results of the semi-continuous digestion of insect frass from the pilot plant operation showed a SMY value of 167 ± 15 mL/gVS, suggesting no process-inhibiting effect caused by the feed material. Although, the high nitrogen content must be taken into account for stable AD performance.

Abstract The discovery of novel by-product feeds for animals, especially cattle, supports an economically viable agricultural community and enhanced stability in the United States food chain. By-products of livestock processing (in this case, paunch manure, or rumen content) could provide the tools necessary to achieve this goal. Paunch manure, the material from ruminant stomachs at the time of harvest, is a waste product of the meat industry and represents a final loss due to cost of disposal. Our objective in this study was to determine the microbial content of fresh versus dried paunch manure in an effort to assess viability as a potential feed source. Fresh paunch manure was collected from cattle at a local abattoir and immediately homogenized for microbial plating. One milliliter of decanted paunch manure was plated on specialized film for determination of colony counts from Enterobacteriaceae, coliform-forming bacteria, Eschericia coli, Salmonella, and yeast and mold. Plates were incubated at 36°C for 24 ± 2 hours. Data were analyzed as a random effects model using PROC MIXED of SAS v. 9.4. In the wet paunch, E. coli had a mean colony count of 3, coliform bacteria of 53, yeast and mold of 0, and Enterobacteriaceae were too numerous to count. In the dry paunch, E. coli had a mean colony count of less than 1, coliform bacteria of 52, yeast and mold of 0, and Enterobacteriaceae less than 1. Source of paunch contributed a majority to the total variance in all instances of the random effects models. Results are interpreted to mean that, given the drastic reduction in microbial loads, paunch manure may represent a viable feedstock for further testing and development.

Low-temperature pretreatment (LTPT, Temp. < 100 °C or 140 °C) has the advantages of low input, simplicity, and energy saving, which makes engineering easy to use for improving biogas production. However, compared with high-temperature pretreatment (>150 °C) that can destroy recalcitrant polymerized matter in biomass, the action mechanism of heat treatment of biomass is unclear. Improving LTPT on biogas yield is often influenced by feedstock type, treatment temperature, exposure time, and fermentation conditions. Such as, even when belonging to the same algal biomass, the response to LTPT varies between species. Therefore, forming a unified method for LTPT to be applied in practice is difficult. This review focuses on the LTPT used in different biomass materials to improve anaerobic digestion performance, including food waste, sludge, animal manure, algae, straw, etc. It also discusses the challenge and cost issues faced during LTPT application according to the energy balance and proposes some proposals for economically promoting the implementation of LTPT.

Concentrated animal feeding operations such as dairies produce a large amount of manure, termed as dairy biomass (DB), which could serve as renewable feedstock for thermal gasification. DB is a low-quality fuel compared to fossil fuels, and hence the product gases have lower heat content; however, the quality of gases can be improved by blending with coals. This paper deals with air-steam fixed-bed counterflow gasification of dairy biomass-Wyoming coal blend (DBWC). The effects of equivalence ratio (1.6<Φ<6.4) and steam-to-fuel ratio (0.4<S:F<0.8) on peak temperatures, gas composition, gross heating value of the products, and energy recovery are presented. According to experimental results, increasing Φ and (S:F) ratios decreases the peak temperature and increases the H2and CO2production, while CO production decreases. On the other hand, the concentrations of CH4and C2H6were lower compared to those of other gases and almost not affected by Φ.

AbstractThis paper presents an assessment of the surplus grass production in the Region of Southern Denmark, and the perspectives of utilizing it in local biogas production. Grass production represents a significant role in the Danish agricultural sector. However, statistical data show an excess production of averagely 12% in the period 2006–2012. Based on spatial analyses and statistical data, the geographical distribution of grass production and consumption was estimated and mapped for the Region of Southern Denmark. An excess production of grass was estimated for several of the municipalities in the Region of Southern Denmark, but the excess production was found to be quite sensitive to the management practice of the grass fields and the productivity of the grass. The yields of excess grass estimated in the sensitive and conservative scenario were found to be sufficient to serve a sole co-substrate in 2–8 biogas plants using animal manure as primary feedstock. The yields in the intensive scenario were assessed to be sufficient to serve a sole co-substrate in 8–16 biogas plants. Alternatively, at least 31% of the regionally produced maize which is exported to the biogas sector could annually be substituted by methane produced from the production of excess grass. The intensive scenario was estimated to have significantly higher grass yields than the sensitive and conservative scenario. The environmental impacts of intensified agricultural management should, however, be assessed carefully in order to ensure that the ecosystems are not increasingly being burdened. The potential of utilizing residual grass for energy production in the region or as an alternative to the maize exported to Northern Germany, was concluded to seem as a promising possibility for a sustainable development of the regional biogas sector. Furthermore, it could provide incentives for establishing new biogas plants in the region and thereby increase the share of manure being digested anaerobically, which could help extrapolate the environmental and climate related benefits documented for the use of digested animal manure as fertilizer on agricultural land.

Nowadays, there is a growing promotion to label products ecologically in European markets. Knowing that daily products have relevant environmental impact associated with their production, it is of utmost importance to analyse all the related production processes for a better understanding of each process impact. The present study analysed the potential environmental impacts of a Portuguese regional product, the Beira Baixa cheese, coming from the largest national sheep milk region. So, a life cycle assessment (LCA) methodology is used from -cradle-to -gate, including the supplying of the animal feedstock. Impact calculations are performed using the ReCiPe midpoint 2008 method, allowing an analysis of the environmental impacts contributing to climate change, terrestrial acidification, freshwater and marine eutrophication of all productive processes. The results have shown that the greatest impacts occur within the milk production process for all four selected impact categories. This happens mainly due to the fodder cultivation process, also necessary to produce animal feed, which contain processes of fertilization and land preparation. The enteric fermentation and manure management processes have also shown relevant contributions. The impact assessment also showed that the cheesemaking industry has practically insignificant impacts. Nonetheless, the cheesemaking industry can promote their business with these results, by advertising and marketing their product as environmentally friendly, with production processes causing reduced impacts, and therefore also their products.

The need to source for alternative use of pigs dung to reduce environmental challenges arising from its application as farm manure prompted the study into the physico-chemical attributes of both the fresh and old pig dung in three pig farms(A,R,U) in Port-Harcourt metropolis. The study examined the pH levels, exchangeable nitrate, extractable phosphate, the total organic carbon and the sulphate using methods described by the pH meter, APHA-4500-O3-B, ASTM D515, Walkley black and ASTM D516 respectively. The results indicated that the dung were alkaline ranging from pH 9-12, the nitrate content was high in fresh dung (16.03-19.40) but considerably low in the dry dung (2.36-2.92), the phosphate values were between 7.59-20.81, the sulphate level falls within 1.84-3.79 whereas the total organic carbon were between 2.36-2.92. The result obtained have showed that the fresh dung could be supplemented with other organic substrate to initiate bioremediation of crude oil polluted soil due to its high nitrate content and the dry dung used as feedstuffs for animal nutrients or feedstock for bioenergy generation because of its high fibre content which will help in reducing the ecosystem contamination by pig waste through recycling.

Commercial citrus (Citrus sp.) groves in Florida use an average of 150 lb/acre (168 kg·ha-1) of elemental nitrogen (N) per year. There are about 853,000 acres (345,000 ha) of commercial citrus requiring about 63,975 tons (62,652 t) of N. At an average analysis of 12% N, about 533,125 tons (483,811 t) of blended nitrogenous fertilizers are applied to citrus annually. To meet this annual N demand from compost, it would be necessary to produce 3,198,750 tons (2,901,906 t) of 2% N compost. The market for high-quality compost products in Florida is far greater than the current or projected production capacity of the state. As long as the cost benefits of compost are clear to citrus growers, demand will always exceed supply. Not all composts are equal in their nutrient availability. The best composts for use as fertilizers are derived from sewage sludge or biosolids, municipal solid waste and sludge, food waste, and/or animal manure combined with a bulking agent such as sawdust or wood chips. Composts made from wood waste as their only feedstock contain large amounts of lignin and cellulose to break down within a reasonable period to directly offset chemical fertilizers. Ultimately, they will mineralize in the soil and provide all of the benefits described earlier, but their rates of availability are in years rather than months, like the other composts.

New markets for organic northern highbush blueberry (Vaccinium corymbosum L.) have stimulated interest in using composts specifically tailored to the plant’s edaphic requirements. Because composts are typically neutral to alkaline in pH (pH 7 to 8), and blueberry requires acidic soil (pH 4.2 to 5.5), we investigated elemental sulfur (S0) addition as a methodology for reducing compost pH. The objectives were to 1) characterize initial compost chemistry, including the pH buffering capacity of compost (acidity required to reduce pH to 5.0), 2) measure changes in compost chemistry accompanying acidification, and 3) evaluate plant growth and mineral nutrition of blueberry in soil amended with an untreated or acidified compost. Ten composts prepared from diverse feedstocks were obtained from municipalities and farms. Addition of finely ground S0 reduced compost pH from 7.2 to 5.3, on average, after 70 d at 22 °C, and increased the solubility of nutrients, including K (from 22 to 36 mmol(+)/L), Ca (from 5 to 19 mmol(+)/L), Mg (from 5 to 20 mmol(+)/L), and Na (from 6 to 9 mmol(+)/L). Sulfate-S, a product of S0 oxidation, also increased from 5 to 45 mmol(−)/L. The composts were incorporated into soil at a high rate (30% v/v) in a greenhouse trial to evaluate their suitability for use in blueberry production. Shoot and root growth were strongly affected by compost chemical characteristics, including pH and electrical conductivity (EC). Potassium in compost was highly variable (2–32 g·kg−1). Concentration of K in the leaves increased positively in response to compost K, whereas shoot dry weight and root growth declined. Leaf Mg also declined in response to compost K, suggesting that elevated K concentrations in compost may cause Mg deficiency. Composts with the highest K were also high in total N, pH, and EC. Compost acidification to pH ≤ 6 improved growth and increased leaf Mg concentration. On the basis of these results, composts derived from animal manures or young plant tissues (e.g., green leaves) appear to be unsuitable for high-rate applications to blueberry because they usually require high amounts of S0 for acidification and are often high in EC and K, whereas those derived from woody materials, such as local yard debris, appear promising based on their C:N ratio, compost acidification requirement, and EC.

Anaerobic digestion is a well-known technology with wide application in the treatment of high-strength organic wastes. The economic feasibility of this type of installation is usually attained thanks to the availability of fiscal incentives. In this review, an analysis of the different factors associated with this biological treatment and a description of alternatives available in literature for increasing performance of the process were provided. The possible integration of this process into a biorefinery as a way for producing energy and chemical products from the conversion of wastes and biomass also analyzed. The future outlook of anaerobic digestion will be closely linked to circular economy principles. Therefore, this technology should be properly integrated into any production system where energy can be recovered from organics. Digestion can play a major role in any transformation process where by-products need further stabilization or it can be the central core of any waste treatment process, modifying the current scheme by a concatenation of several activities with the aim of increasing the efficiency of the conversion. Thus, current plants dedicated to the treatment of wastewaters, animal manures, or food wastes can become specialized centers for producing bio-energy and green chemicals. However, high installation costs, feedstock dispersion and market distortions were recognized as the main parameters negatively affecting these alternatives.

The concepts of sustainability and vulnerability are complementary and closely linked; mitigating the vulnerability of the human environment/climate change can increase its resilience or sustainability. Climate change can increase existing vulnerabilities and deepen socioeconomic imbalances. Measures to reduce and adapt to the effects of climate change are needed in the livestock sector, as they can help reduce the damage caused by natural disasters and other effects of climate change. The future effects of climate change are a significant challenge for livestock managers, users of livestock products and other players, as they may face a number of problems, such as the qualitative and quantitative decline in cereals (feedstock), depletion of conventional sources of energy that provide the electricity and heat needed for animal husbandry, damage to animal shelters, changes in flood frequency and the effects of flooding on the process of spreading manure on land and unforeseen operating and maintenance costs. The adaptation of the intensive animal husbandry process to climate change is a complex process considering the variability of effects, physical vulnerability, degree of socioeconomic development of the entire analyzed area, natural adaptability, health services and disaster surveillance mechanisms. The purpose of this study is to help local authorities in the process of preparing for this transition in a way that takes into account not only socioeconomic factors but also the development constraints imposed by climate change. The studied area, Ciumeghiu–Avram Iancu, located in the southern part of Bihor County, Romania, has been designated as a disadvantaged area of socioeconomic development so that economic agents can apply for the financing of rural development projects with co-financing from European funds (up to 90%). The study presents an analysis of economic development (zootechnical activities) in the southern part of Bihor County, Romania in relation to the climatic vulnerability of the area. Knowing the changes induced in an area by climate change is still a challenge for any local community, and for a socioeconomically vulnerable area, such as the study area, it is important to have at hand studies that can indicate the directions and constraints of development in dictated by these changes. Through this study, we aimed to identify a correlation between the changes induced by climate change and the development capacity of livestock farms, as many economic agents have developed or are developing technical projects for the construction of animal farms in this area. This study is based on the requirements of European reference documents, standards and guidelines. Based on the data available at this time, the applied risk analysis methodology identified a moderate risk associated with increasing extreme temperatures, changes in average precipitation, increasing average temperature, availability of water/drought resources, floods, desertification and risks associated with soil erosion, and the risk of vegetation fires. The correlation of all these factors led us to the conclusion that the area allows for the strictly controlled development of new livestock farms based on plans for the development of territorial units in the area. These units must include desertified areas and define the areas for planting vegetal curtains that will both reduce the phenomenon of erosion and block the circulation of air masses with odor released from the activity of animal husbandry and manure management. The results of the analysis show that it is necessary to take into account the diverse nature of environmental evolution/climate change in different areas of economic development specific to a development area.

North East India is rich in natural resources including various plant‐based biomasses. The plant biomass includes forests, energy crops, crop and agroprocessing residues, animal manures and algal biomass. Organic debris can be recycled and reused and have many possible uses depending upon size, quality, species and volume of the material. Biomass as an alternative energy source has received much importance in terms of future energy security. Biomass based energy technologies may be a viable option considering the availability of rich bioresources in North East India. The production of biodiesel from the seeds of oil bearing plants and microalgae is also one form of biomass utilization. Several species of microalgae are present in the wetlands of this region which however have hitherto remained untapped. Many microalgal strains have been collected and research has been undertaken to screen the biodiesel potential of isolated and identified strains of microalgae native to this region. The abundant biomass of this region also offers suitable substrates for production of mushroom. Moreover, several varieties of edible mushrooms grow wild in this region, which are being domesticated and cultivated for large‐scale production. Availability of large amount of crop and other plant residues offers ample scope for conversion of these biomasses into useful products such as vermicompost and other biofertilizers. The rationale behind this type of approach is to focus on judicious utilization of natural resources towards sustainable development of the country in general and the North East India in particular. This review highlight the potential biomass resources of Northeast Indian region, the challenges and opportunities arising from increasing demands for biomass as well the current technologies available for exploring these biomass resources towards sustainable utilization.

Lead and cadmium studies have been conducted in the egg eco-system trophic chain, which is a continuation study on the chemical heterogeneity of the biosphere, assessed at the ecosystem level. For the realization of the ecologilization, a two-module model of an eco-technical system for production of eggs with models of the two main types of trophic chains is proposed: pasture and detritus type.The main product of the linearity of the technological processes in livestock breeding is fertilizer. From the point of view of efficient management of eco-technical systems to minimize environmental risk, the ecological assessment of the fertilizer for the purpose of its utilization is appropriate. It belongs to the Odum Classification Conglomerates I (1975), which includes organic substances that are potentials of nutrients and energy, and should be utilized as resources for recipients in agro-ecological or aquatic ecosystems. The fertilizer is materially different from other products under this group due to the large number of pathogenic microorganisms. Organic substances in the fertilizer are a risk factor due to the emission of greenhouse gases and toxic substances to the atmosphere and pathogenic microorganisms are biological pollutants with high risk potential due to the risk of it causing human and animal diseases.Our research has focused on the quality of products used for human food and the particularities of the movement of matter in eco-technical systems (Baykov, 1994, Baykov & Tyrawska, 1991, Baykov et al., 1996, Baykov et al. 2003). The experiments were carried out in models of eco-technical systems for eggs on the scale of "mesocosmos" via classification of Odum (1986) by analyzing the physicochemical indicators of the two elements of the incoming stream: feedstock and drinking water and an assessment of the chemical heterogeneity at the ecosystem level was performed by analyzing and hygienically assessing the physical characteristics of products used for human food.Proposed, are criteria for assessing the ecological risk of chemical heterogeneity at ecosystem level: eco-technical Clark (Ec), Clark of safety (Cs), Clark of concentrating (Cc) and Clark of technology (Ct). The results show the possibility of assessing environmental risk through the Cs criterion applied to mass of the egg/ feedstock /and for the processed manure. The ecological risk is managed through the Cs and Ct criteria by regulating the amount of toxic factors in the input stream to guarantee safe for human health secondary biological production.

The quantity of municipal solid waste (MSW) generation is escalating at an alarming rate with every passing year alongside the modernization of our economy. Unfortunately, the majority of this waste remains uncollected or ends up in open dumping and followed by uncontrolled burning. Citing the deep-rooted consequences, open dumping should be absolutely abandoned and scientific interventions should be aggressively exercised to reclaim the municipal brownfields. The present research work undertook the judicial task of assessing the comparative feasibility of biomining and scientific capping as a technology selection for reclamation of about a decade old 120 million tons of waste chunk laying at Jawahar Nagar dump yard. Primary dump samples were collected from various locations, considering depth as a variable. While leachate and groundwater samples were collected from Malkaram lake and preinstalled borewells receptively. Additionally, the ambient air quality and noise level also been ascertained within the buffer zone. The blended representative solid sample was segregated using a 70 mm mesh size trommel into organic and inorganic fractions. The organic fraction was composted using a lab-scale aerobic static pile composting (ASPC) while the trommel reject was processed as refuse derived fuel (RDF). Evidently, the compost lagged quality and depicted nutrient deficiency. While the burning of RDF produced siloxane gas, significantly due to elevated silicon level in the primary waste. Furthermore, due to the prolonged leaching tenure and seasonal dilution, the concentration of legacy leachate was relatively weaker. Borewell samples collected from a depth of 20 feet also portrayed minor contamination up to 500 meters horizontal radius. The issue of leachability can solely be resolved with the capping of the existing dump and the end product quality derived from the biomining process is highly questionable. Thus, handling such large quantity capping is a befitting option over biomining for Jawahar Nagar dumpsite. INTRODUCTION Presently, in India due to rapid urbanization and industrialization, the generation of MSW has been increasing tremendously and also expected to continue a similar trend in the future (Scott, 1995; Bhat et al., 2017; Sethurajan et al., 2018; Sharma et al., 2018). Annually, the comprehensive urban MSW generation in India is more than 62 million tons. Metro cities are the mammoth contributor of the entire chunk and waste production had already reached an alarming figure of 50,000 tonnes/day. While the waste generation from the tier 2 cities is also rigorously escalating and presently contribute up to 20,000 tones/day (Sharma et al., 2018). A study conducted by the central pollution control board (CPCB) revealed MSW generation in India is increasing at a distressing rate of 5 % per annum with a sharp escalation in the quantities of domestic hazardous waste (Sharma et al., 2018). With major financial constraints, inefficacy of collection, treatment, and disposal incurs further reasons to worry. So far India has miserably failed to set up wholesome source segregation and collection method. Presently, the country spends more than 60% of its annual waste management budget only in collection. Besides, only 20% or less of the collected materials are scientifically handled and treated. Citing the statistics, it is evident that the majority of the MSW is simply gets dumped on the low laying grounds located somewhere on the outskirts of the cities. The precipitation, infiltration, surface water runoff, bird menace, rodent interference etc. triggers the vulnerability of waste and leads to mal odor, ground and surface water contamination, human and environmental health deterioration (Jayawardhana et al., 2016). Further, the perseverance of the inorganic and inert fractions leads to soil contamination, poses a fire threat, and also may incur carcinogenicity and acute toxicity among the animals (Mir et al., 2021). There are numerous techniques for the reclamation and remediation of the dumpsites, includes processes such as capping and closure, in-situ vitrification, sub-surface cut-off walls, and waste biomining (Chakrabarti and Dubey, 2015; Thakare and Nandi, 2016). Waste biomining is a stable way to get rid of the entire range of problems associated with open dumping and reclaim valuable land (Kaksonen et al., 2017). There are several instances including reclamation of Mumbai Gorai dump yard by IL & FS Environment, 70 – 80 years old 12,00,000 tons of dump clearance by Nagar Nigam Indore within a minute span of 3 years and many more. But the process of biomining is highly sensitive and case-specific. The success of the process solely depends on factors such as characteristics of the waste, efficacy of the effective microorganism culture, acceptability of the processed end product at the local market etc. (Jerez, 2017; Banerjee et al., 2017; Venkiteela, 2020). Contrarily, though the scientific capping is not an end-to-end solution but still advisable in the cases where the quantity of waste is gigantic, land scarcity is prevalent, no nearby industries to consume the end products etc. Mehta et al. (2018) have also supported the above claim based on the assessment of locations specific MSW dump reclamation case studies. While in another Nagpur-based case study conducted by Ashootosh et al. (2020) reported the superiority of the biominingprocess over simple land capping due to the favorability of the local conditions. Capping eliminates the environmental interference and thereby reduces biosphere contamination and leachate generation. Further, it captivates rodent and vector breeding and thereby curtails the spreading of communicable diseases and improves aesthetics. But right consolidation through compaction and execution is utmost necessary in the above case. As non-compaction and faulty sloping will easily lead to heavy settlement and slope failure (Berkun et al., 2005; Al-Ghouti et al., 2021). The present study has been pursued with the primary objective to run a techno-commercial assessment between scientific capping and biomining. While the secondary objective was to ascertain the level of contamination and propose mitigative measures. MATERIALS AND METHODStudy Area Spanning over 350 acres of a precious piece of land at the outskirts of Hyderabad city, Jawahar Nagar dumping yard was brutally utilized by the Greater Hyderabad Municipal Corporation (GHMC) for open dumping for a prolonged tenure of 10 years. It housed nearly 12 lakh metric tons of heterogeneous solid and domestic hazardous waste and continues polluting until 2015, until the Ramky group was offered to cap the legacy dumping and scientifically handle the site. The present study has been facilitated at Hyderabad Municipal Solid Waste Limited, formerly known as Jawahar Nagar dump yard to analyze and assess the feasibility of bio-mining as handling and management alternate to the existing practice of scientific capping. The epicenter of processing and disposal facility is lying approximately on the cross-section of 17°31'24.45"N and 78°35'23.37"E. As per the contract, the comprehensive legacy dumping to be capped in three phases over about 150 acres of area and Ramky has significantly entered the phase two of the operation only within a span of five years by successfully capping more than half of the legacy footprint. Sampling Methodology The waste pile was divided into three layers namely, base, middle, and top. A uniform amount of sample was collected from the successive layers of all five different corners which cover north, south, east, west, and central of the garbage pile. Sampling inspections were performed using a manual auger besides large samples were collected using a JCB excavator. The top six-inch layer of the pile was removed to avoid any contamination while collecting the samples and 5-10 kg of sample was collected from each of the locations. Further, intermediate and bottom layer samples were collected by digging a 500 mm diameter hole through the heap. A composite was prepared by a homogenized blending of all the fifteen grub samples. The blend was distributed into four equal quadrants and the top and bottom quadrants were eliminated diagonally while the left-over quadrants were mixed thoroughly. This process was repeated until a sample of the required bulk of 20 kg is obtained. Surface and subsurface water samples from borewell were collected in and around the facility. Piezometric monitoring borewells located near the landfills were utilized for the subsurface sample collection. While a rainwater pond turned leachate lake named Malkaram was determined as the primary source for leachate collection. Buffer samples were collected from Ambedkar Nagar, the nearby colony exiting at a distance of only 300 meters. Lab-scale Experimentation The representative sample was characterized for composition and further screened through a 70 mm mesh size trommel. The trommel permeate was considered as the organic fraction while the reject was mostly inorganics and inert. The organics were subjected to ASPC. The quantity of the air required is arrived using the method delineated below (Figure 1). MSW Pile size: 2m x 0.5m x 0.5m Volume of pile: 0.5 m3 Average Density of MSW: 620 Kg/m3 Weight of pile: 310 Kg Nitrogen required for matured compost: 9300 mg/kg dry : 9300 X 310 mg : 2.88 x 106 mg : 2.88 Kg Total air required: 2.88 x 100/76 [as Nitrogen in air is 76% by weight] : 3.79 Kg of dry air : 3.79/1.225 m3 [@ 15 deg C density of air 1.225 kg/m3] : 3.1 m3 This air is to be supplied for 100 min / day for 0.5 m pile Air flow rate required: 3.1 x 60/100 = 1.86 m3/h (for practical purpose a flowrate of 2 m3/h was maintained). The maturation period was considered as 28 days and post-maturation, the stabilized material was further cured for 24 hours and screened using 12 mm and 4 mm trommel respectively to obtain the desired product quality and particle size. Whereas, the trommel reject was evenly spreader on the copper trays and dried in an oven at 1050C for 2 hours. The dried material was micronized to the size of 50 mm or below using a scissor and inert such as glass, sand, stone etc. were segregated manually (Mohan and Joseph, 2020). Concurrently, a bench-scale capped landfill prototype was built using the below-mentioned procedure to evaluate the factors such as settlement and slope stability. A 30 mm thick low permeable soil was laid on the top of the waste, followed by a 60 mm layer of compacted clay liner (CCL). Each join between successive liner material was closely monitored. A 1.5 mm thick HDPE liner was placed on the top of the CCL. A 285 GSM geotextile membrane was placed as the successive above layer followed by a 15 mm thick drainage media layer. A further layer of geotextile membrane was placed on top of the drainage media for better stabilization, grip, and strength. The top vegetative soil layer of 45 mm thickness was laid off on top of the geotextile media and St. Augustine grass was rooted (Cortellazzo et al., 2020; Ashford et al., 2000). 2.4 Sample Analysis pH, Electrical Conductivity (EC) and Turbidity of the samples were analyzed using pH, EC-TDS, and Nephelometer of Mettler Toledo. The pH meter was calibrated with the buffer solution of 4.0, 7.0 & 9.12 at a controlled temperature. EC-TDS meter was calibrated with 0.1 M KCL having 12.8 mS/cm of conductivity. Nephelometer was calibrated with Formazine solution of 10 & 100 NTU. Total Dissolved Solids (TDS), (mg/L) was performed using the gravimetric method at 1800C in the oven. Titrimetric parameters such as Total Alkalinity as CaCO3 (mg/L), Total Hardness as CaCO3 (mg/L), Chloride as Cl- (mg/L), Calcium as Ca2+ (mg/L), Residual Free Chlorine (RFC), (mg/L) were analyzed using APHA (American Public Health Associations) method, 23rd Edition, 2017. Total Kjeldahl Nitrogen (mg/L) and Ammonical Nitrogen (mg/L) were performed through distillation followed by titration with H2SO4 as a titrant. Sulphide as S2- was done with the Iodometric method after distillation. Each titrimetric parameter was analyzed in triplicate after standardizing the titrant with required reagents and crossed checked by keeping a check standard. Sodium as Na (mg/L) and Potassium as K (mg/L) were performed using Flame Photometer. The photometer was calibrated with different standards from 10 to 100 (mg/L) standard solutions. The leachate sample was diluted enough to get the value within the standard range and cross-checked with check standards at the same time. Chemical Oxygen Demand (COD), (mg/L) was performed using the open reflux method for 2 hours at 1500C in COD Digestor. Biochemical Oxygen Demand (BOD), (mg/L) was performed using the alkali iodide azide method for 3 days. The samples were kept in a BOD incubator at 270C for 3 days. It was kept in duplicate to have a check on quality control. Sulphate was analyzed by the gravimetric method instead of turbidimetric or through UV-Visible spectrophotometer as its concentration was found more than 40 mg/L. Nitrate as NO3- was analyzed after filtration at 220-275 nm, while Hexavalent Chromium as Cr6+ was analyzed at 540 nm in the UV-Vis. Parameters like Cyanide as CN-, Fluoride as F-, and Phenolic Compounds were gone through a distillation process followed by UV-Vis. The distillation process ensures the removal of interferences presents either positive or negative. For the parameters like Total Iron or Ferric Iron, the samples were digested properly with the required reagents on the hot plate before analyzing in UV-Vis. For the metal analysis the water samples were digested at a temperature of 1000C using aqua regia as a media. The samples were digested to one-fourth of the volume on a hot plate. The recommended wavelengths as per APHA 3120 B were selected for each of the metals. The standard graph was plotted for each of the metals before analysis and crossed checked with the check standard at the same time. Parameters such as bulk density and particle size were performed through the certified beaker and sieve. The percentage of moisture content was estimated using the oven by keeping the compost sample for 2 hours at 1050C. C/N ratio was estimated through CHNS analyzer keeping sulfanilamide as a check standard. The analysis was performed by extracting the desired component in the desired solution prescribed in the method followed by converting the same from mg/L to mg/Kg. RESULTS AND DISCUSSION An exhaustive bench-study has been pursued and real-time samples were collected and analyzed for all possible parameters to determine the pros and cons attributed to both processes. The investigation begins by collecting the samples and concluded by impact assessment studies inclusive of the buffer zone. Both solid, liquid, and gaseous samples were precisely investigated to opt for the best solution. A detailed finding of the investigation is summarized below. Primarily, the representative solid sample was characterized through a manual separation process and the results are portrayed in Figure 1. Compost Characterization ASPC of the organic fraction has resulted in a recovery of 46.7% of the initial load. While 53.3% of the influent mass were inert and barely degradable fraction contributes to reject, the rest 4.1% is miscellaneous process loss. The processed compost was extensively analyzed including for metal contamination and the same is tabulated in Table 1. The value of C/N ratio, OC, TN, K2O, P2O5, and NPK evidently portrays the shortcoming in terms of nutrient availability. Though it is highly enriched in organic carbon and thus the same can be effectively utilized as a soil preconditioner. Ayilara et al. (2020) also reported a similar finding, where the city compost sourced from MSW lagged major plant nutrients. RDF Characterization Processed trommel rejects constitute cloth, rexine, leather, jute, paper, plastics, coir and other inert contributed to RDF. The fraction of inert was as high as 37.2% of the overall RDF mass and it mostly constituted glass and sand. The combined weight of sand and glass fragments contributed 73.5% of the total inert, while the rest was stone and small brickbats. The higher level of silicon associated with the presence of glass and sand yielded siloxane and triggered the possibility of kiln corrosion. A detailed RDF analysis report is enclosed in Table 2. The values explicitly portray the quality of RDF is moderately lower and higher salts concentration is extremely prevalent. With relatively lower NCV and such high salt concentration, the above specimen will certainly pose a corrosion threat to the kiln and shall be either neglected as kiln feed or can be utilized after dilution with Grade III RDF quality. Further, such high ash generation will also induct high transportation and landfill charges. Leachate Characterization The Malkaram leachate lake is the end result of prolonged, slow, and steady mixing of the legacy leachate through the existing fissure cracks in the sheath rock bottom profile. Apparently, the concentration of leachate is significantly lower due to the dilution. Samples were analyzed in triplicates and the mean value is tabulated here in Table 3. The metal concertation and rest of the parameter values are well within the secondary treatment influent range, except for TDS. Thus, a modular aerobic biological treatment unit such as moving bed biofilm bioreactor (MBBR) or membrane bioreactor (MBR) would be a well-suited pick. However, a reverse osmosis (RO) system needs to be installed to get rid of the high TDS content. The permeate of RO can be reused back into the system. Whereas, the reject can be converted into dried powder through forced evaporation mechanisms. The higher concentration of salts in RDF collaterally justifies the elevated TDS level in leachate. In a leachate impact assessment study performed by El-Salam and Abu-Zuid (2015) the reported BOD/COD ratio of 0.69 is greater than double the value of 0.301 reported in Table 3. Though the difference in both the values are quite high, it is relatable and justifiable by the huge age difference of the source waste. The primarily characterized data is of a fresh leachate generated from regular MSW, while the later one is from a decade old waste that barely has any unstabilized organic content. Groundwater Contamination The obvious reason for downward leachate infiltration and osmotic movement facilitates groundwater contamination. Both surface and subsurface water samples were collected within the dump yard and the buffer zone and analyzed using the standard methods. The results are portrayed in Table 4. The slightly alkaline pH of the borewell sample is an indication of the ongoing anaerobic process. The dissolved oxygen value of 3.5 mg/L further validates the correlation. Higher TDS and hardness values are self-indicative of elevated salt concentration in source waste. Eventually, the same interfered with the RDF quality. Positively in the case of all the parameters, a successive decrement in pollution concentration has been spotted from dump ground towards the buffer zone. In a similar study conducted by Singh et al. (2016) at Varanasi, Uttar Pradesh the reported concentration of the parameters is significantly higher than reported in Table 4. The basic reason behind variation is the dissimilarities of the local soil profile. The sandy and clay loam soil profile of Varanasi allows a greater rate of percolation and infiltration. While the bottom sheath rock profile at Jawahar Nagar permits the only a minute to little percolation rate. The difference in percolation rate is directly correlated to the concentration levels in this case. Contrarily, Kurakalva et al. (2016) have reported much-elevated pollutant concertation both in ground and surface water for a study conducted at the same site in 2016. The higher concentration is relatable to the fact of the non-closure of the open dump back then. Capping activity had at Jawahar Nagar gained its pace 2018 onwards and capping for the primary section of 70 acres got concluded only during mid of 2019. Due to the decrement in runoff and percolation, the quality of both surface and subsurface water has improved drastically. Impact Assessment The odor and groundwater contamination are two of the primary issues that triggered a massive public agitation initially. The root causes of both the issues are identified as rainwater percolation and anaerobic digestion respectively. Eventually, the completion of the capping process would resolve both the problems effectively. Other non-tangential impacts include nausea; headache; irritation of the eye, nasal cavity, and throat; diarrhoeal diseases; vector-borne disease, cattle toxicity etc. Scientific capping can easily cater as the wholesome solution for all (Cortellazzo et al., 2020). Yu et al. (2018) had performed an extensive study to comprehend the relativity of respiratory sickness and MSW borne air pollution. The study made a couple of dreadful revelations such as gases released due to the anaerobic digestion of MSW such as methane, hydrogen sulphide, and ammonia incur detrimental impact on Lysozyme and secretory immunoglobulin A (SIgA). While SO2 was reported as the lung capacity and functionality reducer. Further, a gender-specific study executed by the same research group revealed, air pollution impacts more severely on male children than the female and retards immune functions. Presently, the area of 351 acres has been developed as Asia’s one of the largest state of the art municipal solid waste processing and disposal facility by Ramky Enviro Engineers Limited. This ensured zero dumping and no further environmental interventions. As legal compliance, the facility monitors the quality of groundwater and ambient air quality in and around the facility on monthly basis to assure the biosafety. The variation in concentration of various monitoring parameters between 2012 to 2020 is summarized in Figure 2. The concentration of each of the parameters are showcased in ppm and a standard equipment error was settled at 3% for respirable dust sampler and multi-gas analyzer (Taheri et al., 2014). Despite all parameter values have gradually increased except for methane, the facility still managed to maintain them well under the regulatory limits. The decrement in methane concentration is directly correlated to the practice of aerobic composting and aeration-based secondary treatment that prevented the formation of the anaerobic atmosphere and henceforth methane generation. While for the rest of the parameters the increment in values is quite substantial and predictable due to the sudden escalation in MSW generation in the past decade in correlation with Gross domestic product (GDP) enhancement. The observed and interpreted impacts due to the elevated pollutant level are in-line with the georeferenced findings reported by Deshmukh and Aher (2016) based on a study conducted at Sangamner, Maharashtra. CONCLUSION The study critically analyzed and investigated every techno-environmental and socio-economic aspect correlated to open dumping. The bench-scale experimentation revealed the efficiency of the single liner scientific capping is fair enough to eliminate any further rainwater infiltration, however, it has no control over the generation of leachate due to the inherent moisture. Internal moisture related issue was anyhow compensated with pertinent compaction prior to dispose of the waste. Contrarily, both the products derived through the biomining process namely, compost and RDF lagged quality due to scantier nutrient content and higher salt and silicon content respectively. Besides, impact assessment studies concede the pollutant concentration in groundwater in and around the plant has drastically diminished post-July 2019 due to the partial completion of waste capping. It also abetted lowering the dust and odor issues relatively in the surrounding. ACKNOWLEDGMENT The authors would like to sincerely acknowledge GHMC, Hyderabad Integrated Municipal Solid Waste Limited, and Ramky Enviro Engineers Limited for enabling us to pursue the sample collection and other necessary onsite activities. Further, the authors would like to register profound acknowledgment to EPTRI for supporting us with the essential experimental facilities. REFERENCES Sharma, A., Gupta, A.K., Ganguly, R. (2018), Impact of open dumping of municipal solid waste on soil properties in mountainous region. Journal of Rock Mechanics and Geotechnical Engineering 10 725-739 (2018). https://doi.org/10.1016/j.jrmge.2017.12.009 Jayawardhana, Y., Kumarathilaka, P., Herath, I., Vithanage, M. (2016) Municipal Solid Waste Biochar for Prevention of Pollution from Landfill Leachate. In: Prasad, M.N.V., Shih, K. (eds) Environmental Materials and Waste. 117-148, Academic Press, United States. https://doi.org/10.1016/B978-0-12-803837-6.00006-8 Kaksonen, A. H., Boxall, N. J., Bohu, T., Usher, K., Morris, C., Wong, P. Y., & Cheng, K. Y. (2017). Recent Advances in Biomining and Microbial Characterisation. Solid State Phenomena, 262, 33–37. https://doi.org/10.4028/www.scientific.net/ssp.262.33 Chakrabarti, M., Dubey, A. Remediation Techniques, for Open Dump Sites, used for the Disposal of Municipal Solid Waste in India. Journal of Basic and Applied Engineering Research 2, 1510-1513 (2015). Jerez, C.A. (2017) Bioleaching and biomining for the industrial recovery of metals. In: Reference module in life sciences. Elsevier, Amsterdam, pp 1–14. ISBN: 978-0-12-809633-8. https://doi.org/10.1016/B978-0-12-809633-8.09185-8 Banerjee, I., Burrell, B., Reed, C., West, A.C., Banta, S. Metals and minerals as a biotechnology feedstock: engineering biomining microbiology for bioenergy applications. CurrOpinBiotechnol. 45, 144-155 (2017). https://doi.org/10.1016/j.copbio.2017.03.009 Sethurajan, M., van Hullebusch, E.D., Nancharaiah, Y.V. Biotechnology in the management and resource recovery from metal bearing solid wastes. Recent advances. J Environ Manage. 211, 138-153 (2018). https://doi.org/10.1016/j.jenvman.2018.01.035 Thakare, S., Nandi, S. Study on Potential of Gasification Technology for Municipal Solid Waste (MSW) in Pune City. Energy Procedia 90, 509-517 (2016). https://doi.org/10.1016/j.egypro.2016.11.218 Bhat, S.A., Singh, J., Singh, K., Vig, A.P. Genotoxicity monitoring of industrial wastes using plant bioassays and management through vermitechnology: A review. Agriculture and Natural Resources 51, 325-337 (2017). https://doi.org/10.1016/j.anres.2017.11.002 Berkun, M., Aras, E., Nemlioglu, S. Disposal of solid waste in Istanbul and along the Black Sea coast of Turkey. Waste Manag. 25, 847-55 (2005). https://doi.org/10.1016/j.wasman.2005.04.004 Scott, K. (1995) MICROFILTRATION. In: Scott, K. (eds) Handbook of Industrial Membranes, 373-429, Elsevier Science, https://doi.org/10.1016/B978-185617233-2/50010-6 Mir, I.S., Cheema, P.P.S., Singh, S.P. Implementation analysis of solid waste management in Ludhiana city of Punjab. Environmental Challenges 2, 100023 (2021). https://doi.org/10.1016/j.envc.2021.100023 Al-Ghouti, M.A., Khan, M., Nasser, M.S., Al-Saad, K., Heng, O.E. Recent advances and applications of municipal solid wastes bottom and fly ashes: Insights into sustainable management and conservation of resources. Environmental Technology & Innovation 21, 101267 (2021). https://doi.org/10.1016/j.eti.2020.101267 Venkiteela, L.K. Status and challenges of solid waste management in Tirupati city. Materials Today: Proceedings 33, 470-474 (2020). https://doi.org/10.1016/j.matpr.2020.05.044. Cortellazzo, G., Mandaglio, M.C., Busana, S. et al. A New Approach for the Design, Construction and Control of Compacted Mineral Liners of a MSW Landfill Capping. Int. J. of Geosynth. and Ground Eng. 6, 49 (2020). https://doi.org/10.1007/s40891-020-00234-x Ayilara, M.S., Olanrewaju, O.S., Babalola, O.O., Odeyemi, O. Waste Management through Composting: Challenges and Potentials. Sustainability 12, 4456 (2020). https://doi.org/10.3390/su12114456 Deshmukh, K.K., Aher, S.P. Assessment of the Impact of Municipal Solid Waste on Groundwater Quality near the Sangamner City using GIS Approach. Water Resour Manage 30, 2425–2443 (2016). https://doi.org/10.1007/s11269-016-1299-5 Singh, S., Raju, N.J., Gossel, W. et al. Assessment of pollution potential of leachate from the municipal solid waste disposal site and its impact on groundwater quality, Varanasi environs, India. Arab J Geosci 9, 131 (2016). https://doi.org/10.1007/s12517-015-2131-x Yu, Y., Yu, Z., Sun, P., Lin, B., Li, L., Wang, Z., Ma, R., Xiang, M., Li, H., Guo, S. Effects of ambient air pollution from municipal solid waste landfill on children's non-specific immunity and respiratory health. Environmental Pollution 236, 382-390 (2018). https://doi.org/10.1016/j.envpol.2017.12.094 El-Salam, M.M.A., Abu-Zuid, G.I. Impact of landfill leachate on the groundwater quality: A case study in Egypt. Journal of Advanced Research 6, 579-586 (2015). https://doi.org/10.1016/j.jare.2014.02.003 Kurakalva, R.M., Aradhi, K.K., Mallela, K.Y., Venkatayogi, S. Assessment of Groundwater Quality in and around the Jawaharnagar Municipal Solid Waste Dumping Site at Greater Hyderabad, Southern India. Procedia Environmental Sciences 35, 328-336 (2016). https://doi.org/10.1016/j.proenv.2016.07.013 Mehta, Y.D., Shastri, Y., Joseph, B. Economic analysis and life cycle impact assessment of municipal solid waste (MSW) disposal: A case study of Mumbai, India. Waste Management & Research 36, 1177-1189 (2018). https://doi.org/10.1177/0734242X18790354 Taheri, M., Gholamalifard, M., Ghazizade, M.J., Rahimoghli, S. Environmental impact assessment of municipal solid waste disposal site in Tabriz, Iran using rapid impact assessment matrix. Impact Assessment and Project Appraisal 32, 162-169 (2014). https://doi.org/110.1080/14615517.2014.896082 Ashootosh, M., Periyaswamy, L., Sunil, K., Hiroshan, H. Mining for recovery as an option for dumpsite rehabilitation: case study from Nagpur, India. Journal of Environmental Engineering and Science 15, 52-60 (2020). https://doi.org/10.1680/jenes.19.00021 Ashford, S.A., Visvanathan, C., Husain, N., Chomsurin, C. Design and construction of engineered municipal solid waste landfills in Thailand. Waste Management & Research 18, 462-470 (2000). https://doi.org/10.1177/0734242X0001800507 Mohan S., Joseph C.P. (2020) Biomining: An Innovative and Practical Solution for Reclamation of Open Dumpsite. In: Kalamdhad A. (eds) Recent Developments in Waste Management. Lecture Notes in Civil Engineering, vol 57. Springer, Singapore. https://doi.org/10.1007/978-981-15-0990-2_12

Abstract Purpose With its substantial CO2eq emissions, the agricultural sector is a significant greenhouse gas (GHG) emitter. Animal manure alone contributes 16% of the total agricultural emissions. With a rapidly increasing demand for animal-based protein, animal wastes are expected to rise if sustainable manure management practices are not implemented. Manures have the potential to be treated to generate valuable products (biofertiliser and biocrude) or feedstock for energy production. Thermochemical conversion technologies such as pyrolysis, combustion, supercritical gasification (SCWG), etc., have demonstrated their potential in manure management and valorisation. This study provides a broader overview of these technologies and envisages future manure valorisation trends. Methods The paper presents a state-of-the-art review of manure valorisation. Characterisation of manure, modelling and optimisation of thermochemical conversion technologies along with life cycle anaalysis (LCA) are also reviewed. Results The literature review highlighted that the thermochemical conversion technologies can generate bio-oils, syngas, H2, biofuels, heat, and biochar as carbon-free fertiliser. The reported calorific value of the produced bio-oil was in the range of 26 MJ/kg to 32 MJ/kg. However, thermochemical conversion technologies are yet to be commercialised. The major challenges associated with the scale-up of manure derived feedstocks are relatively high moisture and ash content, lower calorific value and higher concentration of impurities (N, Cl, and S). LCA studies conclude that gasification presents a sustainable option for manure valorisation as it is economical with modest environmental threats. Significance of Study This review briefly states the current challenges faced in manure management and presents the case for a sustainable valorisation of animal manures using thermochemical technologies. The economic, environmental and societal advantages of these technologies are presented in order to promote the scientific and industrial development of the subject in the academic and research community. Conclusions Thermochemical conversion technologies are promising for manure valorisation for energy and nutrient recovery. However, their commercialisation viability needs wide-ranging evaluations such as techno-economics, life-cycle analysis, technology take-up and identification of stakeholders. There should be clear-cut policies to support such technologies. It should be advocated amongst communities and industries, which necessitates marketing by the governments to secure a clean energy future for the planet. Graphical Abstract

Anaerobic digestion (AD) has been widely used to resolve the problem of organic wastes worldwide. Previous studies showed that the types of feedstock have a great influence on the AD microbiome, and a huge number of AD populations are migrated from upstream feedstocks. However, the changes of microbial compositions from feedstock to AD digestate are still less understood. We collected feedstock samples from 56 full-scale biogas plants, generated 1,716 Gb feedstock metagenomic data in total, and constructed the first comprehensive microbial gene catalog of feedstock containing 25.2 million genes. Our result indicated that the predominant phyla in feedstock are Firmicutes, Bacteroidetes, and Proteobacteria, which is similar to that in AD digestate, and the microbial diversity of feedstock samples is higher than that of AD digestate samples. In addition, the relative abundance of most genes involved in methanogenesis increase from feedstock to AD digestate. Besides, the amount of antibiotic resistance genes (ARGs) and pathogenic bacteria in AD are effectively reduced compared to feedstocks. This study provides a comprehensive microbial gene catalog of feedstock, and deepens the understanding of variation of microbial communities from feedstock to AD digestate of full-scale AD. The results also suggest the potential of AD to reduce the level of ARGs and pathogens in animal manure.

We find that there is sufficient technical feedstock availability for Greece to reach its medium-term targets on the production and use of advanced biofuels, renewable gases, electrofuels and recycled carbon fuels for the Greek transport sector. Our analysis suggests that the biomass fraction of municipal solid waste, the biomass fraction of industrial waste, animal manure and sewage sludge, tree prunings, carbon dioxide feedstocks from industrial sources and refuse derived fuels/plastics are feedstocks with sufficient availability until 2050 for the production of renewable fuels and gases for the transport sector in Greece. As a rough indicator, if all the technically achievable feedstocks covered in this study are converted into associated advanced fuels (excluding recycled carbon fuels), this could equate to 7% in 2020, 8.2% in 2030, 9.3% in 2040 and 10.3% in 2050 of the total energy consumed in the transport sector. With policy support, the production of biomethane from the biomass fraction of municipal solid waste, hydrotreated vegetable oil and recycled carbon fuels have possibilities in Greece by 2030, while electrofuels and biomethane from other sources have possibilities by 2040 and lignocellulosic ethanol does not have possibilities in the long run due to limited feedstocks and high costs.

One of the approaches for recycling and reusing agricultural and animal wastes is to pyrolyse the residues and subsequently use them as soil amendments. The prevalence of several feedstocks suggests that it is necessary to investigate the optimal combinations of feedstocks and pyrolysis temperature for use as soil amendments. This study was done to evaluate five combinations of raw materials (sugarcane bagasse, rice husk, cow manure and pine wood) and their biochars produced by slow pyrolysis at 300°C and 500°C for soil amendment. Several physicochemical properties (electrical conductivity (EC), pH, cation exchange capacity (CEC), total organic matter content (C) total porosity (TP), total nitrogen (N), particle density (PD) and bulk density (BD)) were investigated. Comparison among feedstocks showed that the highest PD, BD and CEC were observed in WM (cow manure-pine wood). The pyrolysis process increased the PD, TP, N and monovalent cations and decreased EC, CEC and BD. Compared to the feedstock, pyrolysis increased the N content, but higher temperatures lowered the N content. Pyrolysis at 500°C reduced the EC, N, CEC and biochar yield by 18%, 13%, 21% and 24% respectively, compared to 300°C. Pyrolysis at 500°C increased the pH, Na+ and K+ by 17%, 12% and 22%, respectively, compared to 300°C. Considering the physicochemical properties of biochar and the costs, the bagasse-wood-rice (BWR) combination and temperature of 300°C are suggested for biochar production for soil amendment.

ABSTRACT The well-known nosocomial pathogen Clostridium difficile has recently been recognized as a community-associated pathogen. As livestock animals carry and shed C. difficile in their feces, animal manure-based composts may play an important role in disseminating toxigenic C. difficile strains into the agricultural environment. The present study surveyed C. difficile contamination of commercially available composts and animal manure. Presumptive C. difficile isolates were confirmed by testing for the tpi housekeeping gene in addition to Gram staining. The confirmed C. difficile isolates were further tested for toxigenicity, PCR ribotype, and susceptibilities to selected antibiotics. C. difficile was found in 51 out of 142 samples (36%). A total of 58 C. difficile strains were isolated from those 51 positive compost/manure samples. The presence of C. difficile in compost did not significantly correlate (P > 0.05) with the physical and most microbiological parameters, including the presence of fecal coliforms. The majority of C. difficile isolates were toxigenic, with 63.8% positive for the toxin A gene (tcdA) and 67.2% positive for the toxin B gene (tcdB). Only 3 isolates (5.17%) were positive for the binary toxins. There were 38 different PCR ribotypes among the 58 C. difficile isolates, and ribotype 106 was the most prevalent, followed by ribotypes 020 and 412. All C. difficile isolates were susceptible to the selected antibiotics, but >50% of the isolates had reduced susceptibility to clindamycin by the agar dilution method. This study indicates that compost may be a reservoir of toxigenic C. difficile strains.IMPORTANCE Clostridium difficile infection (CDI) is a leading cause of antibiotic-associated diarrhea in health care facilities in developed countries. Extended hospital stays and recurrences severely increase the cost of treatments and the high mortality rate that is observed among the elderly. Community-associated CDI cases that occur without any recent contact with the hospital environment are increasing. Studies have reported the isolation of virulent C. difficile strains from water, soil, meat, vegetables, pets, livestock animals, and animal manure. The objective of this study was to isolate and characterize C. difficile strains from animal manure and commercially available compost products. Our results demonstrate that not only unprocessed animal manure but also finished composts made of different feedstocks can serve as a reservoir for C. difficile as well. Most importantly, our study revealed that properly processed compost is a potential source of toxigenic and clindamycin-resistant C. difficile isolates.

Abstract Background Animal bedding remains an underutilized source of raw material for bioethanol production, despite the economic and environmental benefits of its use. Further research concerning the optimization of the production process is needed, as previously tested pretreatment methods have not increased the conversion efficiency to the levels necessary for commercialization of the process. Results We propose steam pretreatment of animal bedding, consisting of a mixture of straw and cow manure, to deliver higher ethanol yields. The temperature, residence time and pH were optimized through response-surface modeling, where pretreatment was evaluated based on the ethanol yield obtained through simultaneous saccharification and fermentation of the whole pretreated slurry. The results show that the best conditions for steam pretreatment are 200 °C, for 5 min at pH 2, at which an ethanol yield of about 70% was obtained. Moreover, the model also showed that the pH had the greatest influence on the ethanol yield, followed by the temperature and then the residence time. Conclusions Based on these results, it appears that steam pretreatment could unlock the potential of animal bedding, as the same conversion efficiencies were achieved as for higher-quality feedstocks such as wheat straw.

Abstract Purpose Cultivated meat (CM) is attracting increased attention as an environmentally sustainable and animal-friendly alternative to conventional meat. As the technology matures, more data are becoming available and uncertainties decline. The goal of this ex-ante life cycle assessment (LCA) was to provide an outlook of the environmental performance of commercial-scale CM production in 2030 and to compare this to conventional animal production in 2030, using recent and often primary data, combined with scenario analysis. Methods This comparative attributional ex-ante LCA used the ReCiPe Midpoint impact assessment method. System boundaries were cradle-to-gate, and the functional unit was 1 kg of meat. Data were collected from over 15 companies active in CM production and its supply chain. Source data include lab-scale primary data from five CM producers, full-scale primary data from processes in comparable manufacturing fields, data from computational models, and data from published literature. Important data have been cross-checked with additional experts. Scenarios were used to represent the variation in data and to assess the influence of important choices such as energy mix. Ambitious benchmarks were made for conventional beef, pork, and chicken production systems, which include efficient intensive European animal agriculture and incorporate potential improvements for 2030. Results and discussion CM is almost three times more efficient in turning crops into meat than chicken, the most efficient animal, and therefore agricultural land use is low. Nitrogen-related and air pollution emissions of CM are also lower because of this efficiency and because CM is produced in a contained system without manure. CM production is energy-intensive, and therefore the energy mix used for production and in its supply chain is important. Using renewable energy, the carbon footprint is lower than beef and pork and comparable to the ambitious benchmark of chicken. Greenhouse gas profiles are different, being mostly CO2 for CM and more CH4 and N2O for conventional meats. Climate hotspots are energy used for maintaining temperature in reactors and for biotechnological production of culture medium ingredients. Conclusions CM has the potential to have a lower environmental impact than ambitious conventional meat benchmarks, for most environmental indicators, most clearly agricultural land use, air pollution, and nitrogen-related emissions. The carbon footprint is substantially lower than that of beef. How it compares to chicken and pork depends on energy mixes. While CM production and its upstream supply chain are energy-intensive, using renewable energy can ensure that it is a sustainable alternative to all conventional meats. Recommendations CM producers should optimize energy efficiency and source additional renewable energy, leverage supply chain collaborations to ensure sustainable feedstocks, and search for the environmental optimum of culture medium through combining low-impact ingredients and high-performance medium formulation. Governments should consider this emerging industry’s increased renewable energy demand and the sustainability potential of freed-up agricultural land. Consumers should consider CM not as an extra option on the menu, but as a substitute to higher-impact products.