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[Display omitted] • Tuning ammonium retention in membrane separation using the acid-base equilibrium. • Selectivity increase of nitrogen/potassium by selective permeation of neutral ammonia. • Dynamic digestate separation producing nitrogen and potassium enriched streams. Extensive nitrogen emissions with negative impact on nature and the environment urge effective valorization of manure and fractionation of nutrients to enable precision fertilization. Typically, manure is fed to a digester to produce biogas. The remaining digestate is then mechanically separated into a solid phosphorous-rich fraction and a liquid fraction containing both NH 4 + and K. These ions are difficult to separate due to their very identical size and charge. We show that with smart tuning of the pH to control the NH 3 /NH 4 + equilibrium, membranes can produce dedicated N and K-rich streams. The increased pH switches the equilibrium towards the neutrally charged solute NH 3 that permeates more easily through the membrane than charged NH 4 + and K+ ions. Experiments with both artificial NH 4 Cl/KCl mixtures as well as real liquid digestate and four different membrane types, ranging from open nanofiltration (NF) to sea water reverse osmosis (RO) membranes were performed. At neutral pH, no N/K selectivity was observed, not for single components nor for mixtures. When the pH was increased towards alkaline environment, distinct selectivity for N/K was obtained both with model solutions and real liquid digestate. At a suitable pH of 10, with >80 % of the total ammonia present as NH 3 , the RO BW membrane showed a large N/K selectivity of 35 in the crossflow system. Additional RO steps at low pH allows subsequent concentration of the formed NH 4 + and K+ fractions. The presented dynamic pH approach proofs that in a two-step RO system both N, and K-enriched fertilizers can be produced from real liquid digestate. [ABSTRACT FROM AUTHOR]

Animal manure in livestock production facilities is a major source of methane (CH 4) and ammonia (NH 3) emissions from agriculture. In this study, we investigated different polyphenol-rich extracts and chemicals including commercial chestnut tannin (CT), shea meal extract (SME) and lignosulfonic acid (LSA) in combination with 1 mM of urease inhibitors acetohydroxamic acid (AHA) and/or sodium fluoride (NaF) to mitigate CH 4 and NH 3 in an in-vitro setup with 0.5 L slurry reactors mimicking slurry pits in livestock facilities. Daily addition of pig feces and urine along with additives were conducted for 28 days at room temperature, while CH 4 and NH 3 emissions were monitored by cavity ring-down spectroscopy (CRDS) continuously. SME and SME + NaF added to slurry reduced CH 4 emission by 72% and 88%, and NH 3 emission by 45% and 52%, respectively. CT + NaF at the CT concentration of 2.6, 4.25 and 8.5 mg mL−1, resulted in 48–55%, 70–72% and 81% reduction in CH 4 emission, and 17–29%, 40–49% and 49% reduction in NH 3 emission, respectively. Emission reduction based on the dosage of CT revealed that the relationship between dosage and emission reduction is not linear, therefore the reduction efficiency was calculated by emission reduction divided by concentration. CH 4 reduction efficiency at the CT concentration of 2.6, 4.25 and 8.5 mg mL−1 were 18–21, 16–17 and 10 % (mg mL−1)−1. Therefore, the optimum dosage of CT was 4.25 mg mL−1. In conclusion, addition of CT and SME along with NaF resulted in significant reductions of both CH 4 and NH 3 emissions, while supplementation of LSA and AHA to CT + NaF did not enhance the mitigation effect. • Slurry dynamics in livestock facilities were systematically mimicked in laboratory. • Polyphenols-rich extracts mitigated methane and ammonia emission from pig slurry. • Supplementation of lignosulfonic acid did not impact methane and ammonia emission. • Supplementation of acetohydroxamic acid did not reduce methane and ammonia emission. • The correlation between chestnut tannin dosage and emission reduction was not linear. [ABSTRACT FROM AUTHOR]

The impact of soil fertilization with animal manure on the spread and persistence of antibiotic resistance in the environment is far from being fully understood. To add knowledge about persistence and correlations between antibiotic residues and antibiotic resistance genes (ARGs) in fertilized soil, a longitudinal soil mesocosm study was conducted. Soil samples were collected from the mesocosms immediately before spreading and then afterward at fifteen time points during a 320-day observation period. Eight ARGs (ermB, sul1, tetA, tetG, tetM, cfr, fexA, and optrA) and the class 1 integron-integrase gene, intI1, were determined in both pig slurry and soil, as well as residues of 36 antibiotics. Soil chemical and biochemical parameters were also measured. Twelve antibiotics were detected in the slurry in the range of 3 µg kg−1–3605 µg kg−1, with doxycycline, lincomycin, and tiamulin being the most abundant, whereas ermB, sul1, and tetM were the predominant ARGs. Before spreading, neither antibiotic residues nor ARGs were detectable in the soil; afterwards, their concentrations mirrored those in the slurry, with a gradual decline over the duration of the experiment. After about three months, the effect of the amendment was almost over, and no further evolution was observed. [ABSTRACT FROM AUTHOR]

Simple Summary: The rise of malodor complaints from residents around swine farms and greenhouse gas (GHG) emissions from manure have become a global concern. Although various technologies have been developed to reduce gas emissions from swine farms, only a few have been successfully applied. In Korea, a bio-liquor circulation system (BCS) that controls odor by diluting slurry pit manure with biologically treated manure (bio-liquor) has been proposed as an odor control technology. However, the successful implementation of BCS has been hindered due to the lack of suitable bioreactor control strategies. Therefore, to effectively use BCS, it is crucial to develop an optimized control technology for bioreactors and system operations. Hence, this study aimed to evaluate the effectiveness of a novel real-time BCS controlled by tracking the time profiles of the oxidation reduction potential (ORP) and pH (mV) within two bioreactors in an experimental swine farm set up to improve manure treatment efficiency and reduce malodor at farm scale. The study's results showed that the real-time BCS successfully controlled and optimized the bioreactor and the entire process, effectively reducing the concentrations of nitrogen and organic matter in the swine manure in the slurry pit, and subsequently the malodor. Recently, circulating biologically treated manure in slurry pits has been used as an odor reduction technology, but few successful results have been reported, due to the lack of proper control strategies for bioreactors. This study was conducted to investigate the performance of the developed real-time controlled bio-liquor circulation system (BCS) at farm scale. The BCS was operated sequentially as per swine manure inflow (anoxic, aerobic, and settling) circulation to the slurry pit. Each operational phase was self-adjusted in real-time using a novel algorithm for detecting the control point on the oxidation reduction potential (ORP) and pH (mV)–time profiles, the nitrogen break point (NBP), and the nitrate knee point (NKP) in the aerobic and anoxic phases, respectively. The NH4-N in the slurry manure was thoroughly removed (100%) in the bioreactor, optimizing the duration of each operational phase by accurately detecting real-time control points. The newly developed real-time BCS decreased the nitrogen and organic matter in the slurry pit by >70%, and the potential ammonia and methane emissions by 75% and 95%, respectively. This study highlights that improved BCS that utilizes ORP tracking and pH (mV)–time profiles can effectively optimize BCS operation, and thereby reduce malodor and GHG emissions from swine farms. [ABSTRACT FROM AUTHOR]

Recently, there has been a significant focus on the issue of pollution caused by livestock and poultry rearing, which is recognized as a prominent contributor to nonpoint source pollution in the agricultural sector. This study employed the life cycle assessment (LCA) methodology to evaluate the environmental impact of several pig manure processing scenarios with the aim of determining the appropriate solid–liquid separation tool for large-scale pig farms. The findings indicate that the utilization of a screw extruder for solid–liquid separation in Scenario 2 has a lower environmental impact. In contrast to Scenario 1, Scenario 2 exhibits reduced environmental potential in the areas of global warming, human toxicity, acidification, and eutrophication. Specifically, the global warming, human toxicity, acidification, and eutrophication impacts decreased by 56%, 81%, 83%, and 273%, respectively, due to the implementation of solid–liquid separation. The type of solid–liquid separation equipment used during the processing of swine manure, as well as the subsequent treatment, have a significant impact on environmental emissions. Compared to Scenario 2, Scenario 3, which utilizes a centrifugal microfilter for solid–liquid separation, exhibits a lower environmental impact in terms of human toxicity, resulting in a reduction of 0.736 kg DCB-eq. In general, solid–liquid separation is a viable and environmentally friendly method for the disposal of waste from large-scale pig farms. The adoption of this method is highly recommended. During its implementation, careful consideration should be given to factors such as separation efficiency and pollution emissions. It is crucial to select appropriate equipment for solid–liquid separation to effectively process the waste. [ABSTRACT FROM AUTHOR]

Manure application as fertilizer can increase environmental exposure risk, as antibiotics, antibiotic resistance bacteria (ARB), and antibiotic resistant genes (ARGs) can be transmitted to agricultural fields, and adjacent natural systems. Understanding how specific antibiotics and ARGs respond within different manure fractions during on-farm management is limited. The study objective was to conduct a mass flow analysis determining the fate of antibiotic resistance factors (antibiotics, ARGs, and ARB) through solid-liquid separation, with the solid fraction continuing through a bedding recovery unit (BRU) via high temperature rotary composting for use of the manure solids as dairy cow bedding. The results show that most of the manure mass containing the antibiotic resistance factors went untreated following solid-liquid separation, with 95% of the mass leaving the separator as a liquid and pumped to a storage lagoon for field application and 5% proceeding to BRU processing. The tetracyclines and tulathromycin sorbed to the manure solids, while the beta lactams, ampicillin, and benzylpenicilloic acid were only found in the liquid fraction. The removal of antibiotic residuals during the BRU composting was insignificant, yet 40%-73% of the antibiotics were in the liquid fraction. The BRU composting was 100% effective in removing the ARB examined. Five of the eight ARGs (intl1, sul1, tetQ, tetX, and tetM) had significant reduction (>95%) following the BRU composting treatment. While the three other ARGs (tetW, ermB, and bla2) remained constant despite treatment. This study highlighted the importance of examining manure management from a mass balance perspective and understanding antibiotic resistance risk factors. [ABSTRACT FROM AUTHOR]

The impact of soil fertilization with animal manure on the spread and persistence of antibiotic resistance in the environment is far from being fully understood. To add knowledge about persistence and correlations between antibiotic residues and antibiotic resistance genes (ARGs) in fertilized soil, a longitudinal soil mesocosm study was conducted. Soil samples were collected from the mesocosms immediately before spreading and then afterward at fifteen time points during a 320-day observation period. Eight ARGs (ermB, sul1, tetA, tetG, tetM, cfr, fexA, and optrA) and the class 1 integron-integrase gene, intI1, were determined in both pig slurry and soil, as well as residues of 36 antibiotics. Soil chemical and biochemical parameters were also measured. Twelve antibiotics were detected in the slurry in the range of 3 µg kg−1–3605 µg kg−1, with doxycycline, lincomycin, and tiamulin being the most abundant, whereas ermB, sul1, and tetM were the predominant ARGs. Before spreading, neither antibiotic residues nor ARGs were detectable in the soil; afterwards, their concentrations mirrored those in the slurry, with a gradual decline over the duration of the experiment. After about three months, the effect of the amendment was almost over, and no further evolution was observed.

The impacts of Co nanoparticles (NPs) on the anaerobic digestion (AD) of cow dung were investigated using kinetic models (modified Gompertze, logistic, and first-order) and experimental measurements. The deviation between the predicted and measured data for biogas yield with modified Gompertze and logistic models were 0.66–2.26% and 1.43–4.19%, respectively. The addition of Co NPs (1–3 mg/L) improved the hydrolysis rate (K) value by 66.66–144% compared with the control. Furthermore, the fertilizer efficiency of effluent with Co NPs was comparable to that of commercial NPK compound fertilizer. The combination of kinetic models and experimental measurements can effectively quantify the impact of Co NPs on AD performance and provide an informed choice for industrial production. [ABSTRACT FROM AUTHOR]

Copyright of Japanese Journal of Swine Science / Nihon Yoton Gakkaishi is the property of Japanese Society of Swine Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The presence of nano-nutrients can be stimulatory for the anaerobic digestion (AD) of hardly degradable wastes and thus enhance process performance. One of the essential trace elements, nickel (Ni), is involved in multiple important enzymes necessary for efficient AD. This study investigated the effects of Ni nanoparticles (NPs) with different concentrations on cattle manure AD performance and effluent chemical composition. The results showed that the highest specific biogas production was attained with 4 mg/L Ni NPs (p<0.05) and was 792.00 mL/g VS compared with cattle manure-only which yielded only 589.20 mL/g VS. Moreover, the addition of 2 mg/L Ni NPs significantly increases the methane yield (p<0.05) by 70.46% compared with cattle manure-only. Besides, H2S production decreased by 16.50%, 90.47%, and 51.89% compared with cattle manure-only when the cattle manure was treated by 1, 2, and 4 mg/L Ni NPs, respectively. The supplementation of bio-digester with 2 mg/L Ni NPs improved the total and volatile solids removal efficiencies by 19.2% and 12.1% and maintained pH at a suitable level (6.8–7.3). FTIR spectrum of effluent presented the addition of Ni NPs changed the intensity and shift of peaks compared with cattle manure-only peak. Moreover, all of the effluent samples from the AD systems using Ni NPs showed stronger fertilizer values, as well as the effluent with 2 mg/L Ni NPs, had the highest sulfide content (31.2%, increase), leading to higher H2S removal efficiency by 47.5%. A first-order kinetic model showed an increase up to 1.88-fold in the hydrolysis rate constant (K), in 4mg/L Ni NPs compared to cattle manure-only, leading to higher biogas yield. [ABSTRACT FROM AUTHOR]

Simple Summary: Manure generated in bovine farms may pose human and animal health risks. If not managed and used properly, these risks may be spread to other areas. The risks can be minimised when farmers are aware of them and apply optimum practices at their farms, at storage, processing, and when manure is applied to land as a fertiliser. This research aims to evaluate the Cypriot bovine farmers' knowledge about the risks from manure and the practices currently applied for manure management through a questionnaire survey. The results indicated some gaps in farmers' knowledge and some deficiencies in employing optimal management practices. The education level and the farming purpose were identified as determinants of the level of farmers' knowledge. The conclusion was that farmers' knowledge must be reinforced through specialised training to ensure proper manure management. Although the current practices partially decrease manure pathogens, interventions to promote the use of more effective treatment methods, such as biogas transformation and composting, would be beneficial. The results could help Cypriot and other competent authorities to develop an action plan to control the health risks by educating farmers, promoting the use of more efficient management methods and developing new legislation. Manure from bovine farms is commonly used as an organic fertiliser. However, if not properly managed, it can spread significant biological and chemical hazards, threatening both human and animal health. The effectiveness of risk control hugely relies on farmers' knowledge regarding safe manure management and on the application of suitable management practices. This study aims to evaluate the knowledge and practices of Cypriot bovine farmers towards safer manure management, from its generation to its final use, in line with the One Health approach. Factors affecting farmers' knowledge and applied practices are also investigated through a questionnaire survey. The questionnaire was developed and sent to all eligible bovine farmers in Cyprus (n = 353), and 30% (n = 105) of them returned the completed questionnaire. Results revealed there are some gaps in farmers' knowledge. The use of manure for fertilising crops dominated. Only half of the farmers stored manure in appropriate facilities, with 28.5% of them using a dedicated area with cement floors and 21.5% utilising leakproof tanks. The majority (65.7%) stored manure for more than three months before its use as a fertiliser in a dried form. In multiple regression analysis, education level and farming purpose were significant determinants of farmer knowledge. In conclusion, Cypriot farmers' knowledge must be reinforced to ensure proper manure management. The results highlight the importance of providing relevant training to farmers. Although the current practices partially decrease manure pathogens, interventions to promote the use of more effective treatment methods, such as biogas transformation and composting, would be beneficial. [ABSTRACT FROM AUTHOR]

Implementing renewable energy technologies for manure treatment to reduce energy consumption and environmental damage is steadily becoming more prevalent. In this work, an air-cooled photovoltaic thermal (PV/T) device was enhanced and constructed to provide energy for bio-composting manure treatment. Experiments were conducted to analyze the performance data such as air supply temperature, energy and exergy efficiency, and mass flow rate. When calculating the mass flow rate of the PV/T-supplied manure treatment technology, factors such as exergy efficiency, and hot air temperature must be considered. The results of the study indicate that the thermal performance of the developed equipment is adequate for manure composting treatment. The thermal exergy efficiencies of the V 2 , V 3 , and V 4 cases are approximately 1/3 greater than the thermal exergy efficiency of the V 1 case, indicating a considerable change in thermal efficiency. The mass flow rate of 0.020 kg/s is determined to be a more suitable set value. Its total exergy efficiency can reach 46.79%, and the apparatus could heat up to 43.63 kg/m2 of compost to begin the bio-composting process. This study lays the groundwork for future research and deployment of PV/T-powered manure treatment devices. • Hot air collected by PV/T meets the required temperature of 25 °C for composting. • Mass flow rate of 0.020 kg/s is deemed more reasonable for best efficiency. • The total exergy efficiency of technology portfolio can reach 46.79%. • The apparatus could heat up to 43.63 kg/m2 of compost in a single day. [ABSTRACT FROM AUTHOR]

Recently, there has been a significant focus on the issue of pollution caused by livestock and poultry rearing, which is recognized as a prominent contributor to nonpoint source pollution in the agricultural sector. This study employed the life cycle assessment (LCA) methodology to evaluate the environmental impact of several pig manure processing scenarios with the aim of determining the appropriate solid–liquid separation tool for large-scale pig farms. The findings indicate that the utilization of a screw extruder for solid–liquid separation in Scenario 2 has a lower environmental impact. In contrast to Scenario 1, Scenario 2 exhibits reduced environmental potential in the areas of global warming, human toxicity, acidification, and eutrophication. Specifically, the global warming, human toxicity, acidification, and eutrophication impacts decreased by 56%, 81%, 83%, and 273%, respectively, due to the implementation of solid–liquid separation. The type of solid–liquid separation equipment used during the processing of swine manure, as well as the subsequent treatment, have a significant impact on environmental emissions. Compared to Scenario 2, Scenario 3, which utilizes a centrifugal microfilter for solid–liquid separation, exhibits a lower environmental impact in terms of human toxicity, resulting in a reduction of 0.736 kg DCB-eq. In general, solid–liquid separation is a viable and environmentally friendly method for the disposal of waste from large-scale pig farms. The adoption of this method is highly recommended. During its implementation, careful consideration should be given to factors such as separation efficiency and pollution emissions. It is crucial to select appropriate equipment for solid–liquid separation to effectively process the waste.

Recently, circulating biologically treated manure in slurry pits has been used as an odor reduction technology, but few successful results have been reported, due to the lack of proper control strategies for bioreactors. This study was conducted to investigate the performance of the developed real-time controlled bio-liquor circulation system (BCS) at farm scale. The BCS was operated sequentially as per swine manure inflow (anoxic, aerobic, and settling) circulation to the slurry pit. Each operational phase was self-adjusted in real-time using a novel algorithm for detecting the control point on the oxidation reduction potential (ORP) and pH (mV)–time profiles, the nitrogen break point (NBP), and the nitrate knee point (NKP) in the aerobic and anoxic phases, respectively. The NH4-N in the slurry manure was thoroughly removed (100%) in the bioreactor, optimizing the duration of each operational phase by accurately detecting real-time control points. The newly developed real-time BCS decreased the nitrogen and organic matter in the slurry pit by >70%, and the potential ammonia and methane emissions by 75% and 95%, respectively. This study highlights that improved BCS that utilizes ORP tracking and pH (mV)–time profiles can effectively optimize BCS operation, and thereby reduce malodor and GHG emissions from swine farms.

Swine manure treatment plants are important reservoirs of plasmid-harboring antibiotic resistance genes (ARGs) and physicochemical contaminants, but the changes in the abundances of plasmids and ARGs, and their interactions with the physicochemical properties of manure, are still unclear. Thus, in the present study, plasmidome and metagenome analyses were conducted for samples collected at different stages in the swine manure treatment process. The results indicated that anaerobic digestion and aerobic digestion were the most efficient stages for reducing the abundances of ARGs in swine manure. However, the plasmids associated with ARGs were not effectively removed in these stages. Through the whole treatment process, the IncL/M, IncQ1, IncHI2A, IncA/C, and IncN plasmid groups had strong correlations (r > 0.8, P < 0.01) with most ARG types, thereby indicating that these plasmids play important roles in the persistence of ARGs in this environment. Furthermore, the pH, total nitrogen, total phosphorus, and four heavy metals (Cu, Zn, As, and Fe) significantly affected the abundances of seven ARG subtypes (tetB(P), ant(6)-Ia, tet44, aph(3′′)-Ib, mefB, tet(L), and tet(39)). In particular, florfenicol had the most positive correlations with ARGs. Our results indicated that nutrients, heavy metals, and antibiotics all contributed to the presence and persistence of plasmid-harboring ARGs. This study provides insights into the fate of plasmids and ARGs, and related factors during the swine manure treatment process, thereby facilitating the development of a new treatment technique for removing ARGs and reducing the public health risk associated with livestock production. [ABSTRACT FROM AUTHOR]

Manure management is a challenge as the animal barns are tend to be larger operations. Electrocoagulation has a great potential to be applied in animal barns because it can effectively separate liquid and solid as well as nitrogen and phosphorus from animal manure. This work evaluated a pilot scale electrocoagulation with low carbon steel as electrodes working on dairy manure, shallow-pit and deep-pit swine manure. Over 66% of the phosphorus in electrocoagulation treated swine manure was recovered in sludge with less than 10% of the phosphorus in the untreated volume. The TN/P 2 O 5 ratio in swine manure sludge after electrocoagulation decreased to 0.52–0.78 while it increased to 10.61–38.56 in the supernatant after electrocoagulation, which significantly reduced the risk of phosphorus overdose as manure fertiliser to pollute the environment. However, the pilot electrocoagulation removed 79.3% of the dairy manure phosphorus into sludge while the sludge volume was 48% of the total volume. The economic analysis showed that an electrocoagulation system in a barn with 2400 head grown-finish pigs for 20 years would add $1.04 and $3.32 per pig of additional annualised cost in a shallow-pit swine barn and deep-pit swine barn, respectively. The environmental benefits of manure nutrient balancing and phosphorus sustainability make it worth to develop electrocoagulation technology on animal barns. [Display omitted] • Electrocoagulation efficiently remove phosphorus from dairy and swine manure. • The system was scale-up with two types of reactors that treated 100 L manure per day. • Over 66% of the phosphorus was concentrated in sludge less than 9% of the total volume. • Economic analysis shows that $1.04 per pig of additional annualized cost in a swine barn. [ABSTRACT FROM AUTHOR]

Manure from bovine farms is commonly used as an organic fertiliser. However, if not properly managed, it can spread significant biological and chemical hazards, threatening both human and animal health. The effectiveness of risk control hugely relies on farmers’ knowledge regarding safe manure management and on the application of suitable management practices. This study aims to evaluate the knowledge and practices of Cypriot bovine farmers towards safer manure management, from its generation to its final use, in line with the One Health approach. Factors affecting farmers’ knowledge and applied practices are also investigated through a questionnaire survey. The questionnaire was developed and sent to all eligible bovine farmers in Cyprus (n = 353), and 30% (n = 105) of them returned the completed questionnaire. Results revealed there are some gaps in farmers’ knowledge. The use of manure for fertilising crops dominated. Only half of the farmers stored manure in appropriate facilities, with 28.5% of them using a dedicated area with cement floors and 21.5% utilising leakproof tanks. The majority (65.7%) stored manure for more than three months before its use as a fertiliser in a dried form. In multiple regression analysis, education level and farming purpose were significant determinants of farmer knowledge. In conclusion, Cypriot farmers’ knowledge must be reinforced to ensure proper manure management. The results highlight the importance of providing relevant training to farmers. Although the current practices partially decrease manure pathogens, interventions to promote the use of more effective treatment methods, such as biogas transformation and composting, would be beneficial.

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 microalgaebased 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. [ABSTRACT FROM AUTHOR]

Swine manure is an alternative to synthetic fertilizers for providing crop nutrients. However, transportation costs, nutrient leakage, and gaseous emissions associated with using swine manure as fertilizer limit its agronomic benefits and cause environmental issues. In this study, we report the efficacy of nutrients (P as ortho-P and N as NH 4 +) recovery scheme from swine manure by batch equilibration and column leaching studies using different combinations of two biochars (untreated control biochar; control-BC and iron-modified biochar; iron-BC) and one zeolite with SiO 2 /Al 2 O 3 = 30:1. Batch study employed different adsorbents (control biochar, followed by iron-BC, and zeolite) to obtain maximum adsorption (98.3% and 35.4%) and optimum desorption (66% and 18%) of P and N from the manure solution (1:5). A series of sand-matrix columns using the best combination of control-BC, iron-BC, and zeolite recovered 13,800 mg kg−1 of P and 4000 mg kg−1 of N from manure solution after tenth cycles of leaching events. XRD and SEM-EDS analyses revealed the association of P with N and Mg, suggesting the adsorption of nutrients mostly through co-adsorption with manure colloids and precipitation as struvite. A series of soil-matrix column studies and a corn seed germination test were conducted to test the nutrient leaching/crop fertilization efficiencies using the recovered adsorbents. Inclusively, results showed that a proper combination of biochar and zeolite could effectively recover and concentrate nutrients from swine manure to develop crop fertilizer for easy transport and use in sustainable agriculture. [Display omitted] • Biochar and zeolite can efficiently concentrate nutrients from swine manure. • Swine manure dilution plays crucial role in nutrient recovery. • Colloidal particles actively participate in ortho-P and NH 4 +-N adsorption. • ∆G0 values suggest sorption of P is exothermic and N is endothermic in nature. • Developed fertilizer showed less N loss as NH 3 compared to urea and s-coated urea. [ABSTRACT FROM AUTHOR]

In most pig barns, intensive breeding is being carried out, and social problems such as manure disposal and large-scale infectious diseases have emerged due to this livestock farming method. In particular, organic matter from the manure is decomposed and odorous gases such as ammonia and hydrogen sulfide are emitted. The emitted harmful gases cause problems such as causing stress in pig barns, reducing immunity, and causing various diseases. To solve these problems, cleaning robots for handling manure in pig barns have been developed, and algorithms for planning optimal routes for autonomous driving or methods for cost reduction due to efficient cleaning are being studied. Most cleaning robots currently in use, employ a method of treating accumulated manure by spraying high-pressure water from a stored water tank. If water can be sprayed only on areas that need cleaning, water consumption can be reduced, so we propose a technology that can determine this through a camera. If it is possible to determine whether cleaning is necessary by segmenting only manure from the image into objects, it is expected to significantly reduce unnecessary water consumption. The purpose of this study is to determine whether cleaning is necessary by dividing excrement into objects from images taken during autonomous driving with a camera mounted on the front of a cleaning robot. The final goal is to obtain a segmented image capable of recognizing only the manure part requiring cleaning from the captured image. The first step acquires image information using an RGB camera. At the beginning of the study, when the number of images is insufficient, the segmentation performance is checked through semantic segmentation using the difference between manure and other objects or backgrounds using image information. Depending on the segmentation performance and the number of acquired images, we plan to use a deep learning-based algorithm in the future. The ultimate goal of this study is to develop a technology for obtaining segmented images capable of recognizing excreta by utilizing image information from captured images. In addition, if only the manure part can be accurately recognized through this study, we plan to apply the technology of spraying water only to the necessary part by using it as information to determine whether cleaning is necessary from the segmented image. Through this, the company plans to apply the technology to self-driving cleaning robots to develop high-efficiency intelligent cleaning robots capable of efficiently handling manure. This achievement was made by the support of the Ministry of Agriculture, Food and Rural Affairs, R&D project(421044043HD030). [ABSTRACT FROM AUTHOR]

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Gastrointestinal bacteria that harbor antibiotic resistance genes (ARG) become enriched with antibiotic use. Livestock manure application to cropland for soil fertility presents a concern that ARG and bacteria may proliferate and be transported in the environment. In the United States, manure applications typically occur during autumn with slow mineralization until spring planting season. A laboratory soil incubation study was conducted mimicking autumn swine manure application to soils with concentrations of selected ARG monitored during simulated 120-day winter incubation with multiple freeze-thaw events. Additionally, the effects of two soil moistures [10 and 30% water holding capacity (WHC)] and two manure treatments [raw versus hydrated lime alkaline stabilization (HLAS)] were assessed. Fourteen tetracycline resistance genes were evaluated; tet(D), tet(G), and tet(L) were detected in background soil while swine manure contained tet(A), tet(B), tet(C), tet(G), tet(M), tet(O), tet(Q), and tet(X). By day 120, the manure-borne tet(M) and tet(O) were still detected while tet(C), tet(D), tet(L), and tet(X) genes were detected less frequently. Other tet resistance genes were detected rarely, if at all. The sum of unique tet resistance genes among all treatments decreased during the incubation from an average of 8.9 to 3.8 unique tet resistance genes. Four resistance elements, intI1, blactx–m–32, sul(I), erm(B), and 16s rRNA genes were measured using quantitative PCR. ARG abundances relative to 16S abundance were initially greater in the raw manure compared to background soil (−1.53 to −3.92 log abundance in manure; −4.02 to

Gastrointestinal bacteria that harbor antibiotic resistance genes (ARG) become enriched with antibiotic use. Livestock manure application to cropland for soil fertility presents a concern that ARG and bacteria may proliferate and be transported in the environment. In the United States, manure applications typically occur during autumn with slow mineralization until spring planting season. A laboratory soil incubation study was conducted mimicking autumn swine manure application to soils with concentrations of selected ARG monitored during simulated 120-day winter incubation with multiple freeze-thaw events. Additionally, the effects of two soil moistures [10 and 30% water holding capacity (WHC)] and two manure treatments [raw versus hydrated lime alkaline stabilization (HLAS)] were assessed. Fourteen tetracycline resistance genes were evaluated; tet (D), tet (G), and tet (L) were detected in background soil while swine manure contained tet (A), tet (B), tet (C), tet (G), tet (M), tet (O), tet (Q), and tet (X). By day 120, the manure-borne tet (M) and tet (O) were still detected while tet (C), tet (D), tet (L), and tet (X) genes were detected less frequently. Other tet resistance genes were detected rarely, if at all. The sum of unique tet resistance genes among all treatments decreased during the incubation from an average of 8.9 to 3.8 unique tet resistance genes. Four resistance elements, int I1, bla ctx–m– 32, sul (I), erm (B), and 16s rRNA genes were measured using quantitative PCR. ARG abundances relative to 16S abundance were initially greater in the raw manure compared to background soil (−1.53 to −3.92 log abundance in manure; −4.02 to <−6.7 log abundance in soil). In the mixed manure/soil, relative abundance of the four resistance elements decreased (0.87 to 1.94 log abundance) during the incubation largely because 16S rRNA genes increased by 1.21 log abundance. Throughout the incubation, the abundance of int I1, bla ctx–m– 32, sul (I), and erm (B) per gram in soil amended with HLAS-treated manure was lower than in soil amended with raw manure. Under low initial soil moisture conditions, HLAS treatment reduced the abundance of int I1 and resulted in loss of bla ctx–m– 32, sul (I), and erm (B)] compared to other treatment-moisture combinations. Although one might expect antibiotic resistance to be relatively unchanged after simulated winter manure application to soil, a variety of changes in diversity and relative abundance can be expected. [ABSTRACT FROM AUTHOR]

Modern practices of industrial farming, such as mineral fertilization, caused a widespread degradation of agricultural land and water bodies in Europe. Different farm management strategies exist to reduce the impact of mineral fertilization while preserving soil productivity. The aim of this paper is to provide a thorough systemic review of contemporary literature exploring factors and conditions affecting EU farmers’ adoption of sustainable farming practices. The specific focus is on widely adopted and empirically explored measures, such as organic farming, manure treatment technologies and manure fertilization, as well as soil and water conservation methods. In total, 23 peer-reviewed studies were extracted by means of Google Scholar covering the time period between 2003 and 2019. The main findings show that farmers’ environmental and economic attitudes in addition to their sources of information have a strong effect on the adoption of organic farming, although there is a lack of evidence of their impact on adopting manure treatment and conservation measures. Similarly, farmers’ age and education are found to systemically influence organic farming adoption, but not adoption of other reviewed technologies. While other factors, such as farm physical characteristics or technological attributes, may be important determinants of adoption, it is hard to recognize definite patterns of their impact across technologies given a shortage of empirical evidence. More research utilizing standardized surveys and methods of analysis is needed to formulate qualified guidelines and recommendations for policymakers. [ABSTRACT FROM AUTHOR]