Solid Fraction Of Manure Research Articles

Revolutionizing biogas generation: Polyethylene tubular digesters for household pig farms

Manure decomposition from animal waste, including farm sludge, is a significant source of methane (CH4) and carbon dioxide (CO2) emissions, aggravating global warming. Addressing this issue is vital for the environment and pivotal in achieving sustainable development goals by combating pollution from agricultural activities. One promising solution is biogas production, which offers threefold benefits including mitigation of global warming, assurance of energy security, and efficient waste management. This can be achieved by optimizing the process using substrates that yield high biogas output while ensuring low water usage and retention. This study focuses on pig farms' biogas potential of liquid and solid manure fractions performed with laboratory-scale batch digesters and enhanced polyethylene tubular digesters for evaluation. From the screening system, the biogas output from pig slurry resulted in CH4 and CO2 in 45 days, achieving 61.44 and 36.35%, respectively. After the initial screening experiment, polyethylene tubular digesters were implemented for biogas production at household pig farms and produced through fermentation in polyethylene tubular digesters under anaerobic conditions and are mainly composed of CH4 (60–64%) and CO2 (29–38%). This study suggested that the pig slurry could be a reliable biomass energy source for biogas and applicable to householders.

DISPOSAL OF MANURE AT THE PIGGERY USING BIODESTRUCTORS OF DIFFERENT ORIGIN

The development of biotechnological methods of disposal of pig waste products is relevant at the current stage. However, the high cost of investment and operation of such technologies limits their application. Therefore, owners of pig farms are constantly looking for compromise solutions that would, on the one hand, ensure compliance with technological requirements for manure removal, and on the other hand, not pollute the environment. The purpose of the work is to improve existing technologies and develop innovative approaches to biotechnological methods of manure disposal. Scientific research was carried out at the piggery of Agroprime Holding LLC of the Odesa region with a capacity of 30,000 heads per year. The considered technology of using biological preparations De-Scentase and Complesin for descentization of manure in underground baths, manure storages, manure sites of the complex. The content of gases in the manure subfloor bath of the piggery due to the use of biological preparations was determined. The conducted monitoring of unpleasant scents and harmful gases confirmed the expediency of using new methods of neutralizing unpleasant scents. It was established that the reconstruction of the separator station by installing a metal hangar and a water-dispersion filtration chamber ensured the neutralization and release of scentous gases into the environment and did not affect the ecological state of the environment negatively. On the basis of the conducted research, the method of wide application of the biological preparation for the disposal of manure has been developed. The improved technology of manure disposal at the piggery, which involves the addition of the microbial destructor drug Complesin to underground baths, as well as to manure storages and manure sites, helps to reduce the release of harmful gases and accelerates the disposal of manure. The technology of utilization of liquid and solid fraction of manure by using biological preparation and vermiculture is highlighted. The experience of using equipment for underground application of liquid manure to fields is presented.

Quantifying Antibiotic Distribution in Solid and Liquid Fractions of Manure Using a Two-Step, Multi-Residue Antibiotic Extraction.

Antibiotic distribution and analysis within liquid and solid fractions of manure are highly variable due to each compound's respective physiochemical properties. This study developed and evaluated a uniform method extracting 10 antibiotics from 4 antibiotic classes (tetracycline, sulfonamides, macrolides, and β-lactam) from unprocessed manure, solid-liquid separated manure, and composted solids. Through systematic manipulation of previously published liquid chromatography tandem mass spectrometry methods; this study developed an extraction protocol with optimized recovery efficiencies for varied manure substrates. The method includes a two-step, liquid-solid extraction using 10 mL of 0.1 M EDTA-McIlviane buffer followed by 10 mL of methanol. Antibiotics recoveries from unprocessed manure, separated liquids, separated solids, and heat-treated solids using the two-step extraction method had relative standard deviations < 30% for all but ceftiofur. Total antibiotic recoveries were 67-131% for tetracyclines, 56% for sulfonamide, 49-53% for macrolides, and 1.3-66% for β-lactams. This is the first study to use one protocol to assess four classes of antibiotics in liquid and solid manure fractions. This study allowed for more precise risk assessment of antibiotic transport in manure waste stream applied to fields as a liquid or solid compost.

ДИНАМИКА СОДЕРЖАНИЯ МИКРОЭЛЕМЕНТОВ В ПОЧВЕ ПРИ ОСВОЕНИИ МАЛОПРОДУКТИВНЫХ ЗАЛЕЖНЫХ ЗЕМЕЛЬ ВЕРХНЕВОЛЖЬЯ

The studies were carried out at LLC Ruch’evskoe-1, Rzhevsky district, Tver region in 2012…2018 during development of low-yielding, previously reclaimed lands that were retired from circulation. The total area of arable land is 5297 hectares, the soils are sod-podzolic, light loamy in terms of particle size distribution. The effect of the systematic application of high doses of organic fertilizers from pig-breeding complexes in the form of solid fraction of manure (60…80 t/ha) and liquid waste (100…120 m3/ha) on the dynamics of the content of copper, zinc, boron and manganese in the arable layer has been studied. It was found that during the six-year observation period on soils with a leaching type of water regime, the average weighted copper content had only positive tendency to increase as the increment to the initial value was 0.1 mg per a kilogram of soil (0.1 mg/kg), which was within the experimental error and amounted to 1.7 mg/kg at the optimal value for the region 2.45 mg/kg. A similar situation is typical in the study of the dynamics of zinc, the average weighted content of which reached 0.9 mg/kg, which is significantly lower than the optimal level of 3.55 mg/kg. Consequently, with the deacidification of fallow lands from the introduction of alkaline organic fertilizers, a significant increase in the available forms of copper and zinc was not noted, which requires additional introduction of microelements to eliminate their deficiency. At the same time, the systematic application of high doses of organic fertilizers significantly improved the provision of low-yielding lands with boron and manganese, the content of which in the arable layer approached the optimal value and at the end of observations amounted to 0.50 and 44.8 mg/kg, respectively, with an optimal level of 0.52 and 50.5 mg/kg.

Influence of fertilizer system on the dynamics of nitrogen content and balance on newly developed lands

Under the conditions of the North-West region, the influence of fertilizer systems and precursors on the dynamics of the accumulation of easily hydrolysable nitrogen and the balance of its total content during the development of unproductive sod-podzolic soils of light granulometric composition was studied. For an eight-year research period, the mineral fertilizer system in the cultivation of barley at the planned yield (40 kg/ha) does not compensate for the loss of easily hydrolysable nitrogen. The organo-mineral system (40 t/ha of organic fertilizers or 100 m3/ha of liquid wastewater from livestock complexes) contributes to an increase in the content of easily hydrolysable nitrogen in the arable soil layer by 2.5 … 5.1 and 2.1 … 5.2 mg/kg of soil, compared to control. Stabilization of the balance of the total nitrogen content occurs with an annual application of 6.9 … 7.2 t/ha of solid fraction of manure or 35 … 37 m3/ha of liquid effluents and expanded reproduction of soil fertility is ensured with the incorporation of 9.7 … 11.0 t/ha solid fraction or 49 … 52 m3/ha of liquid waste. The most intensive accumulation of easily hydrolysable nitrogen is observed when using spring rape as a precursor, on the background of which the highest yield of barley was also obtained.

Reducing greenhouse gas emissions and stabilizing nutrients from dairy manure using chemical coagulation.

Two primary concerns of dairies that store manure wastewater in anaerobic ponds are greenhouse gas (GHG) emissions and unpredictable nutrient availability after applying it to forage crops. Solid-liquid separation of dairy manure wastewater with chemical coagulants significantly reduces the fraction of organic matter stored in anaerobic conditions. However, the effects of coagulants on methane emissions from ponds and nutrient availability following field application are not well understood. In this experiment, several metal salts and organic polymers were used to coagulate dairy manure wastewater for separation into solid (floc) and liquid (effluent) fractions. The coagulants tested were ferric sulfate, ferric chloride, polyaluminum chloride, Superfloc C-569, and chitosan. An anaerobic incubation of manure effluent to simulate liquid manure storage and an aerobic incubation of manure floc-amended soil to simulate field application were conducted with analysis of GHGs and carbon and nitrogen transformations. The treatment of chemically separating organic matter from manure wastewater effectively eliminated methane emissions under anaerobic conditions in the laboratory. In the solid manure fraction, organic carbon was stabilized in the chemically separated flocs, and, apart from flocs produced with ferric iron, nitrogen mineralization was reduced as well. Carbon dioxide emissions were also reduced from the flocs applied to soil compared with untreated manure solids.

A critical review on livestock manure biorefinery technologies: Sustainability, challenges, and future perspectives

An ever increasing demand for animal protein products has posed serious challenges for managing the increasing quantities of livestock manure. The choice of treatment technologies is still a complicated task and considerable debates over this issue still continue. To build a clearer picture of manure treatment framework, this study was conducted to review the most frequently employed manure management technologies from their state of the art, challenges, sustainability, environmental regulations and incentives, and improvement strategies perspectives. The results showed that most treatment technologies have focused on the solid fraction of manure while the liquid fraction still remains a potential environmental threat. Compared to other waste to energy solutions, anaerobic digestion is the most mature technology to upgrade manure's organic matter into renewable energy, however the problems associated with high investment costs, operating parameters, manure collection, and digestate management have hindered its developments in rural areas in developing countries. Bio-oil production through hydrothermal liquification is also a promising solution, as it can directly convert the wet manure into biofuel. However, lipid-poor nature of manure, operational difficulties, and the need for downstream process to remove nitrogenous compounds from the final product necessitate further research. Livestock manure management (both solid and liquid fractions) under biorefinery approach seems an inevitable solution for future sustainable development to meet circular bioeconomy requirements. Much research is still required to establish a systematic framework based on regional requirements to develop an integrated manure nutrient recycling and manure management planning with minimum environmental risks and maximum profit.

Biofermentation of organic waste from a pig-breeding complex in a drum-type installa-tion

Relevance. In modern pig-breeding complexes, manure is processed by separation producing the liquid and solid manure fractions. The complexes also generate other types of organic waste. Testing the process of producing the organic fertilizer based on the solid organic waste of a pig-breeding complex in a drum-type biofermenter.Material and methods. The processing of a mixture of two types of solid fractions of pig slurry and the waste from mechanical cleaning of grain into an organic fertilizer in a drum-type biofermentation unit was tested. The tested material was produced on the pig-breeding complex with the closed production cycle located in Leningrad Region. The optimization criterion was the temperature of the mixture in the installation. The controlling factors were the aeration frequency, the air supply rate to the biofermenter, and the rotation interval of the drum. Assumed values of the tested factors were: the moisture content of the mixture of 55–65% and the density of the mixture of 400– 600 kg/m3. The standard methods for statistical and experimental data analysis were applied.Results. Four operation modes of the biofermenter were tested, of which only one allowed to achieve the heating of the mixture above 55 °C and a stable course of the biofermentation process. Under this mode, the aeration rate was 5 min/h; the air supply rate to the biofermenter was 10 m/s; and the drum rotation interval was every 12 hours. The significance of the factors in a multivariate experiment was considered; the mathematical model was analyzed using the steepest ascent method. Considering the identified operation mode, 12 drum-type biofermenters with the working volume of 31.3 m3 each will be needed to process the solid fraction of manure produced on the pig-breeding complex with the animal stock of 107,000 head and the output of the solid fraction of manure of 90 tons per day. A building with a floor area of 1000 m2 will be required to place these biofermenters. This area is 113.4 times smaller than the area of the watertight pad for clamps to process the manure by the passive composting technology. Nitrogen emissions will be reduced by 6.3% owing to the intense mineralization of nitrogen in the fermented mixture.

Choosing a Manure Recycling System for a Dairy Farm with Tied Housing

Development and testing of new more effi cient and environmentally friendly waste management technologies is one of the priorities of agroecology aimed at introducing the basic principles of the sustainable use of natural resources. An example of such a technology may be the recycling of cattle manure into the bedding for farm animals. (Research purpose) Feasibility study of diff erent technological options for the production of bedding from manure under conditions of an operating livestock enterprise. (Materials and methods) In the study, three options of this technology were considered as exemplifi ed by a dairy farm for 100 milking cows: Option 1 – separation of manure into fractions followed by aerobic fermentation of the solid manure fraction in a drum-type fermentor; Option 2 – mixing the unprocessed manure with peat and its subsequent aerobic fermentation in a drumtype fermentor; Option 3 – mixing the unprocessed manure with peat and its subsequent aerobic fermentation in a chambertype fermentor. The author has estimated capital and operation costs as well as labour inputs and payback period. (Results and discussion) The number of facilities and equipment required for manure recycling and the resulting product storage has been calculated for each option. The author has made an economic assessment of the three options. For Option 1, the capital costs of implementation amount to 18.2 million roubles, operating costs – 8.9 million roubles, labour inputs – 5.1 man-hour per tonne, and the payback period – 2.1 years. It has been revealed that options 2 and 3 feature high capital costs, therefore, bedding production with the use of peat proved to be ineffi cient. (Conclusions) The study has allowed to determine the most effi cient and economically feasible technological method of manure recycling: manure separation into fractions with subsequent aerobic fermentation of the solid fraction in a drum-type fermentor. Options 2 and 3 have been found economically unfeasible.

On the Effect of Aqueous Ammonia Soaking Pre-Treatment on Continuous Anaerobic Digestion of Digested Swine Manure Fibers.

(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.

Patterns of dairy manure management in China

Abstract: The dairy industry in China is rapidly developing, particularly in terms of the upscaling of dairy farms. However, nutrient-rich manure brings challenges to the sustainability of the dairy industry. This study investigated and reviewed the patterns of dairy manure management in China, and the results indicate that dairy manure could be used as an organic fertilizer because of its high organic nutrient content and low metal content. However, legislation prohibits the application of untreated (raw) dairy manure. An existing technology for handling animal slurry is the separation into a liquid and a solid manure fraction. The solid fraction can be used as compost and bedding materials, and it has limited environmental risk. However, the emissions from the storage of liquid manure need further attention. The cycle of manure production, collection, transportation, separation and storage can only be closed if the nutrients are eventually applied to grass and arable land according to crop needs. Therefore, distribution of knowledge on nutrient levels, crop needs and nutrient management plans, supported by legislation on maximum application standards, is needed. In this way, an environmentally friendly development of dairy manure management might be possible. Keywords: dairy manure, manure handling pattern, legislation, nutrient recycling, emissions DOI: 10.3965/j.ijabe.20171003.3048 Citation: Li C Y, Qiao W, Melse R W, Li L J, de Buisonje F E, Wang Y J, et al. Patterns of dairy manure management in China. Int J Agric & Biol Eng, 2017; 10(3): 227–236.

The effect of different pyrolysis temperatures on the speciation and availability in soil of P in biochar produced from the solid fraction of manure

Biochar application to agricultural land has been proposed as a means for improving phosphorus (P) availability in soil. The purpose of the current study was to understand how pyrolysis temperature affects P speciation in biochar and how this affects availability of P in the amended soil. Biochar was produced at different temperatures from digestate solids. The primary species of P in digestate solids were simple calcium phosphates. However, a high co-occurrence of magnesium (Mg) and P, indicated that struvite or other magnesium phosphates may also be important species. At low temperatures, pyrolysis had little effect on P speciation; however, as the temperature increased above 600 °C, the P gradually became more thermodynamically stable in species such as apatite. At very high temperatures above 1000 °C, there were indications of reduced forms of P. Biochar production decreased the immediate availability of P in comparison with the original digestate solids. However, for biochar produced at low temperatures, availability quickly increased to the same levels as in the digestate solids. For biochar produced at higher temperatures, availability remained depressed for much longer. The low availability of P in the biochar produced at high temperatures can probably be explained by the formation of less soluble P species in the biochar. In contrast, the transient decrease of availability of the P in the biochar produced at low temperatures can be explained by mechanisms, such as sorption on biochar, which gradually decreases because of oxidation of the biochar surfaces or changes in pH around the biochar particles.

Санитарно-паразитологическая и экономическая оценка методов обеззараживания стоков и навоза на свинокомплексах

Objective of research: the sanitary-veterinary and economic evaluation of the disinfecting effect of different technologies applied for decontamination of livestock manure and sewage from invasive pathogens of pigs as well as for conversion of these wastes. Materials and methods: The degree of contamination of liquid manure from pig farms with eggs and helminth larvae, cysts and oocysts of parasitic protozoa, was studied on the samples collected once a month at farms of the Moscow region, and once every two months at farms of the Republic of Mordovia. Sampling, transportation and investigation of samples were carried out by the method of A. Cherepanov (1972). Samples were taken in the morning at 3-5 points using IMOP sampler 1000. At the sampling point, an inventory was created where the date, location, selection point and its sample volume were indicated. To prevent the development of microflora in the samples, a certain amount of preserving agent was added. When sampling solid manure fraction from the surface, middle and lower level, manure mass was selected horizontally at each level from 3-5 points, thoroughly mixed, then the averaged sample (1.0 kg) was placed in a plastic bag. To confirm the viability of helminth eggs detected by coproovoscopic examinations, eggs were transferred with a micropipette into Petri dishes and cultured in an thermostat at a temperature 26˚C in a humid environment, periodically aerating and observing the development of the embryo. Comparative assessment of the effectiveness of the treatment facilities in selected pig farms was performed by comparing the number of invasive elements in 1 liter of liquid manure entering and flowing out of the treatment facilities. Results and discussion: at all three selected pig farms, the most intense infections with helminth eggs, cysts and oocysts parasitic protozoa were found in raw sewage, what indicates a lack of effectiveness of anti-parasitic measures at the farm. JSC “Mordovia bacon” with 54 thousand pig heads a year is the only one of three inspected farms, where liquid manure is separated into fractions, followed by disinfestation of solid fraction on concrete pads with further application of manure as an organic fertilizer. Due to mechanical separation of liquid manure into fractions applied at this farm, the number of parasitic elements of internal parasites of pigs (eggs of Ascaris, trihotsefal, esophagitis, coccidia oocysts and cysts balantidiums) in 1 kg solid fraction was 586 ind. The efficiency of decontamination of liquid manure from parasitic elements, taking into account this treatment method was 53,6-73,4%. Biothermal decontamination of solid fraction of manure piles is achieved within 3-5 months (100%), depending on the season and used in fields as organic fertilizer.

Enhancing the biomethane potential of liquid dairy cow manure by addition of solid manure fractions.

To assess the effect of adding solid manure fractions on the biomethane potential (BMP) of liquid dairy cow manure and on the biokinetic parameters of the process. The methanogenic potential of liquid dairy cow manure was strongly effected by adding a solid manure fraction. The 90/10% (w/w) liquid/solid manure fraction mixture was the best substrate for CH4 production. This substrate mixture improved by 50% the final CH4 production per g substrate and decreased the lag time by 220% relative to the reference BMP test without the addition. Moreover, the addition of 20% solid manure fraction adversely affected both the final CH4 production and the maximum methane production rate, while increased the lag time by 400% compared to the reference BMP test without addition. Liquid dairy cow manure should be supplemented with no more than 10% of solid manure fraction in order to improve the biomethane potential of this important agro-industrial residue.

AMMONOX: Ammonia for Enhancing Biogas Yield and Reducing NOx—Analysis of Effects of Aqueous Ammonia Soaking on Manure Fibers

Laboratory experiments have shown that aqueous ammonia soaking (AAS) is a promising treatment for increasing the methane yield of the solid fraction of manure (fibers). AMMONOX is a new concept based on the sustainable use of ammonia for enhancing biogas pro- duction at biogas plants digesting manure. The proposed process is based on an optimized AAS treatment of manure fibers in combination with an efficient ammonia recovery step. The enhancement of biogas production is achieved by enriching manure with AAS-treated fibers, or other ligno- cellulosic residues, while the ammonia recovered can be used for fulfilling the needs of the treatment itself. Excess of ammonia could be produced when ammonia is recov- ered from both the treated fibers and the digester effluent, which could be used for the reduction of NOx in biogas- based electricity generation by gas turbines. In this survey study, the importance of different factors affecting the performance of AAS of digested manure fibers was in- vestigated in order to conclude on which variables to op- timize. Principal component analysis of the present data was used for a preliminary analysis of effects. The tem- perature and the ammonia concentration during AAS were the most influencing variables in terms of methane yield under the conditions tested. Further experiments should be conducted in order to investigate the effect of shorter AAS duration than the ones tested (lower than 24 h) and for assessing the importance of the solid-to-liquid ratio in the treatment mixture; the follow-up campaign should be op- timized with respect to possible interactions/correlated experimental factor effects.

Measurement of methane production from pig and cattle manure in Lithuania

The current experiment was conducted to quantify methane (CH4) productivity from pig and cattle manure. The manure was collected from twenty commercial farms in different parts of Lithuania. The biogas production and ultimate methane production were measured in a batch experiment according to the international standard. Manure was stored for a period of up to 70 days at constant 35 ± 1°C temperature. Infrared or electrochemical detection was adopted to analyze the methane and carbon dioxide content in biogas. Theoretical methane production was calculated according to the chemical composition of manure. In our study, the theoretical methane production from the total volatile solids (VS) for both pig and cattle manure was in the range of 0.41–0.46 m3 kg-1 CH4 VS. Theoretical methane production from easily degradable volatile solids was by 26.72% lower than that from total volatile solids. During the storage period, up to 64% of total manure volatile solids and up to 89% of easily degradable volatile solids had decomposed. The ultimate methane production for pig liquid manure was the highest and reached 0.29 m3 kg-1 CH4 VS. The methane production for pig solid fraction of manure was 0.12 m 3 kg-1 CH4 VS, for the liquid fraction of pig manure – 0.18 m3 kg-1 CH4 VS. The methane production for dairy cattle liquid and solid manure, also non dairy cattle solid manure reached 0.20–0.21 m3 kg-1 CH4 VS. For dairy cattle slurry the methane production was the lowest – 0.05 m3 kg-1 CH4 VS, in comparison with other samples. Our study showed that methane production for pig and cattle manure in Lithuania was from 13% to 36% lower than the default values recommended for Europe (IPCC Guidelines..., 2006) and are used for calculations of national methane emission from manure.

Enhanced methane productivity from manure fibers by aqueous ammonia soaking pretreatment

The necessity of increasing the methane productivity of manure based biogas plants has triggered the application of anaerobic digestion to the separated solid fraction of manure, with the challenge that its high lignocellulosic fibers content is difficult to digest and thus makes anaerobic digestion process slow and economically unfavourable. In the present study, aqueous ammonia soaking (AAS) was investigated as a pretreatment method to increase methane potential of swine manure fibers. 3days at 22°C were the optimal conditions among the ones tested (1, 3, and 5days at 22 and 55°C) for increasing the methane potential of manure fibers. AAS pretreatment exhibited a significant effect on methane production rate and potential. It was found that AAS for 3days at 22°C resulted at a 30–80% and 178% increase in methane yield from digested and raw manure fibers, respectively. Batch anaerobic digestion of AAS-treated digested manure fibers could stand loadings as high as 100g TS/l inoculum with no inhibition problems. Enzymatic hydrolysis tests applied to AAS-pretreated fibers resulted to 80% and 65% hydrolysis efficiency of glucan and xylan compared to insignificant numbers for non-pretreated fibers confirming thus that AAS effect on methane yield and production rate is due to the facilitation of hydrolysis step of anaerobic digestion process. This is attributed to AAS directly affecting the disintegration step and thus releasing carbohydrates, which can be further hydrolyzed, from the lignocellulosic matrix.

Fate of steroid hormones and endocrine activities in swine manure disposal and treatment facilities

Manure may contain high concern endocrine-disrupting compounds (EDCs) such as steroid hormones, naturally produced by pigs, which are present at μg L −1 levels. Manure may also contain other EDCs such as nonylphenols (NP), polycyclic aromatic hydrocarbons (PAHs) and dioxins. Thus, once manure is applied to the land as soil fertilizer these compounds may reach aquifers and consequently living organisms, inducing abnormal endocrine responses. In France, manure is generally stored in anaerobic tanks prior spreading on land; when nitrogen removal is requested, manure is treated by aerobic processes before spreading. However, little is known about the fate of hormones and multiple endocrine-disrupting activities in such manure disposal and treatment systems. Here, we determined the fate of hormones and diverse endocrine activities during manure storage and treatment by combining chemical analysis and in vitro quantification of estrogen (ER), aryl hydrocarbon (AhR), androgen (AR), pregnane-X (PXR) and peroxysome proliferator-activated γ (PPARγ) receptor-mediated activities. Our results show that manure contains large quantities of hormones and activates ER and AhR, two of the nuclear receptors studied. Most of these endocrine activities were found in the solid fraction of manure and appeared to be induced mainly by hormones and other unidentified pollutants. Hormones, ER and AhR activities found in manure were poorly removed during manure storage but were efficiently removed by aerobic treatment of manure.

Leaching of nitrate and phosphorus after autumn and spring application of separated solid animal manures to winter wheat

AbstractAnimal slurry can be separated into solid and liquid manure fractions to facilitate the transport of nutrients from livestock farms. In Denmark, untreated slurry is normally applied in spring whereas the solid fraction may be applied in autumn, causing increased risk of nitrate and phosphorus (P) leaching. We studied the leaching of nitrate and P in lysimeters with winter wheat crops (Triticum aestivum L.) after autumn incorporation versus spring surface application of solid manure fractions, and we compared also spring applications of mineral N fertilizer and pig slurry. Leaching was compared on a loamy sand and a sandy loam soil. The leaching experiment lasted for 2 yr, and the whole experiment was replicated twice. Nitrate leaching was generally low (19–34 kg N/ha) after spring applications of mineral fertilizer and manures. Nitrate leaching increased significantly after autumn application of the solid manures, and the extra nitrate leached was equivalent to 23–35% of total manure N and corresponded to the ammonium content of the manures. After spring application of solid manures and pig slurry, only a slight rise in N leaching was observed during the following autumn/winter (<5% of total manure N). Total P leaching was 40–165 g P/ha/yr, and the application of solid manure in autumn did not increase P leaching. The nitrogen fertilizer replacement value of solid manure N was similar after autumn and spring application (17–32% of total N). We conclude that from an environmental perspective, solid manure fractions should not be applied to winter wheat on sandy and sandy loam soils under humid North European conditions.

How can we improve biomethane production per unit of feedstock in biogas plants?

Biogas production is one of the number of tools that may be used to alleviate the problems of global warming, energy security and waste management. Biogas plants can be difficult to sustain from a financial perspective. The facilities must be financially optimized through use of substrates with high biogas potential, low water content and low retention requirement. This research carried out in laboratory scale batch digesters assessed the biogas potential of energy crops (maize and grass silage) and solid manure fractions from manure separation units. The ultimate methane productivity in terms of volatile solids (VS) was determined as 330, 161, 230, 236, 361 L/kg VS from raw pig slurry, filter pressed manure fiber (FPMF), chemically precipitated manure fiber (CPMF), maize silage and grass silage respectively. Methane productivity based on mass (L/kg substrate) was significantly higher in FPMF (55 L/kg substrate), maize silage (68 L/kg substrate) and grass silage (45–124 L/kg substrate (depending on dry solids of feedstock)) as in comparison to raw pig slurry (10 L/kg substrate). The use of these materials as co-substrates with raw pig slurry will increase significantly the biomethane yield per unit feedstock in the biogas plant.