Hvad kan biogasanlæggene gøre for at sikre en optimal gødningsproduktion?

Presentation of the possibilities for making new fertilizer products from degassed biomas

Biogas potential from forbs and grass-clover mixture with the application of near infrared spectroscopy

This study investigated the potentials of forbs; caraway, chicory, red clover and ribwort plantain as substrates for biogas production. One-, two- and four-cut systems were implemented and the influence on dry matter yields, chemical compositions and methane yields were examined. The two- and four-cut systems resulted in higher dry matter yields (kg [total solid, TS] ha-1) compared to the one-cut system. The effect of plant compositions on biogas potentials was not evident. Cumulative methane yields (LCH4 kg-1 [volatile solid, VS]) were varied from 279 to 321 (chicory), 279 to 323 (caraway), 273 to 296 (ribwort plantain), 263 to 328 (red clover) and 320 to 352 (grass-clover mixture), respectively. Methane yield was modelled by modified Gompertz equation for comparison of methane production rate. Near infrared spectroscopy showed potential as a tool for biogas and chemical composition prediction. The best prediction models were obtained for methane yield at 29 days (99 samples), cellulose, acid detergent fibre, neutral detergent fibre and crude protein, (R2 > 0.9)

Biogas production by co-ensiling catch crops and straw, effect of substrate blend and microbial communities

The combination of catch crop (CC) and barley straw(S) for biogas production was investigated in order to evaluate the ensiling process in batch assay and in continuous process. Based on two new agriculture strategies designed to produce energy and improve nutrient cycling in organic farming are being evaluated, one of them consisting on the harvest of straw and catch crop in different periods whereas the other strategy consists on harvesting them at the same time. Catch crops is promoted to reduce nutrient leaching during rainy season and straw that is not used for animal feeding or bedding is generally left in the field. Mixtures of CC and S provides several advantages: 1) Provides adequate TS for silage, 2) Absorbs the silage effluent, 3) Produces high LAB activity, and 4) Provides an optimal C/N for anaerobic digestion (AD). The effect of feeding compositions (straw or manurea ddition) on the microbial community structures were also investigated

Anaerobic mono-digestion of lucerne, grass and forbs - Influence of species and cutting frequency

In the present study, biogas potentials of multispecies swards including grass, lucerne, caraway, ribwort plantain and chicory from two- and four-cut regimes (Mix-2 and Mix-4) for mono-digestion applying batch and continuous modes under lab-scale conditions were investigated. The gas yields in terms of volatile solids (VS)loaded from Mix-2 and Mix-4 were compared with pure stand lucerne from the four cuts regime (Lu-4). The batch test results indicate that methane yield on a VS basis was highest from Mix-4 (295 L kg−1), followed by Mix-2 (281 L kg−1) and Lu-4 (255 L kg−1). The results were confirmed with continuous experiments, during which the reactor digesting Mix-4 was stable throughout the experiment with low ammonia and volatile fatty acid (VFA)concentration. Meanwhile, mono-digestion of Lu-4 led to elevated VFA levels, even at a comparatively low organic loading rate of 1.76 g L−1 d−1 but it was not possible to ascertain whether this was due to organic overload alone or if high ammonia levels during Lu-4 digestion were contributing to the reduced performance. It was found that four cuts per year was suitable for a lab-scale mono-digestion system as the substrate was less fibrous and has lower dry matter content, which minimize blockage during feeding and digestate unloading. Micronutrient concentrations, including cobalt, nickel and molybdenum decreased over time during the continuous experiments and were critically lower than the optimum concentration required by methanogens, particularly in Mix-4, but the gas yields of the reactor treating this substrate showed no decrease over time

Effect of anaerobic digestion of cover crops and straw on N and S availability in the digestate

Lack of nutrients and poor synchrony between nutrient availability and crop demand are often reasons for low yields in organic farming. A field experiment conducted in Denmark aims to use cover crops (CC) to produce extra biomass for biogas production and afterwards utilize the digestate as nitrogen (N) and sulfur (S) fertilizer. The influence of the main crop harvest time and the straw management on biomass production of cover crops is investigated. A spring barley crop and an under-sown CC (clover and chicory mixture) were established to compare early and late barley harvest time and different straw management, including a treatment with high stubble. The dry matter (DM) yield of CC in October was 2.5 t/ha for early barley harvest and 2.3 t/ha for late harvest. At early barley harvest with high stubble treatment, an extra DM yield of 1.3 t/ha was obtained. The harvested CC was ensiled and used as substrates for mono- and co-digestion with cattle manure in 15L digesters. The silages contained mixtures of CC and straw at ratios 1:0, 3:1 and 10:1 (fresh weight basis). Anaerobic digestion (AD) increased the fraction of NH4+ in total N from 0.07 to 0.41 in a reactor fed with CC silage only, for example. This increase was lower for reactors fed with higher ratio of straw in the silage mixture. In 2018, the N fertilizer value of cattle manure and different digestates and raw silages are tested in a new spring barley crop in confined microplots. Yields and N uptake of spring barley will be measured and the fertilizer value of digested materials will be compared with corresponding undigested cover crops. In addition, the fate of N and S in the soil with different cover crop-straw mixtures and digestion management will be investigated

Digestates from cover crop, straw and cattle slurry mixtures as nutrient source in organic cropping system

Yields in organic arable farming are way below the potential. The reasons are due to the lack of nutrients and poor synchrony between nutrient availability and crop demand (Möller and Müller, 2012). Nitrogen (N) is often the most limiting nutrient for biomass production. Nitrogen available in soil is taken up by plant almost exclusively in mineral form. Yet, limitation of mineralized N in soil is often the problem especially in organic farming. In crop management systems using only organic substrates, the challenge is to increase the N mineral fertilizer value of organic substrates in order for organic farming to rely on organic fertilizer sources. Anaerobic digestion has the potential to increase the nutrients availability (Webb et al., 2013). Cover crops (CC) are useful to reduce nutrient leaching losses and they have the potential to produce extra biomass for biogas production. If a CC with symbiotic N fixation is used the CC can also contribute with extra N to the system. The biomass production in cover crops is influenced by the main crop harvest time and probably by the straw management. The aim of the current study is to quantify the influence of main crop harvest time and straw management and the inclusion of anaerobic digestion of cover crops and straw on N utilization and on potential biogas production. A comparison between mono- and co-digestion of cover crops, straw and cattle slurry is also included

Effectiveness of treatment with pegylated interferon and ribavirin in an unselected population of patients with chronic hepatitis C: A Danish nationwide cohort study

<p>Abstract</p> <p>Background</p> <p>The effect of peginterferon and ribavirin treatment on chronic hepatitis C virus (HCV) infection has been established in several controlled clinical studies. However, the effectiveness of treatment and predictors of treatment success in routine clinical practice remains to be established. Our aim was to estimate the effectiveness of peginterferon and ribavirin treatment in unselected HCV patients handled in routine clinical practice. The endpoint was sustained virological response (SVR), determined by the absence of HCV RNA 24 weeks after the end of treatment.</p> <p>Methods</p> <p>We determined the proportion of SVR in a nationwide, population-based cohort of 432 patients with chronic HCV infection who were starting treatment, and analyzed the impact of known covariates on SVR by using a logistic regression analysis.</p> <p>Results</p> <p>The majority of treated patients had genotype 1 (133 patients) and genotype 2/3 (285 patients) infections, with 44% and 72%, respectively, obtaining SVR. Other than genotype, the predictors of SVR were age ≤ 45 years at the start of treatment, completion of unmodified treatment, the absence of cirrhosis and non-European origin.</p> <p>Conclusions</p> <p>The effectiveness of peginterferon and ribavirin treatment for chronic hepatitis C in a routine clinical practice is comparable to that observed in controlled clinical trials, with a higher SVR rate in genotype 2 and 3 patients compared to genotype 1 patients. Our data further indicate that age at start of treatment is a strong predictor of SVR irrespective of HCV genotype, with patients 45 years or younger having a higher SVR rate.</p

Incidence and survival of oesophageal and gastric cancer in England between 1998 and 2007, a population-based study

BACKGROUND: Major changes in the incidence of oesophageal and gastric cancers have been reported internationally. This study describes recent trends in incidence and survival of subgroups of oesophageal and gastric cancer in England between 1998 and 2007 and considers the implications for cancer services and policy. METHODS: Data on 133,804 English patients diagnosed with oesophageal and gastric cancer between 1998 and 2007 were extracted from the National Cancer Data Repository. Using information on anatomical site and tumour morphology, data were divided into six groups; upper and middle oesophagus, lower oesophagus, oesophagus with an unspecified anatomical site, cardia, non-cardia stomach, and stomach with an unspecified anatomical site. Age-standardised incidence rates (per 100,000 European standard population) were calculated for each group by year of diagnosis and by socioeconomic deprivation. Survival was estimated using the Kaplan-Meier method. RESULTS: The majority of oesophageal cancers were in the lower third of the oesophagus (58%). Stomach with an unspecified anatomical site was the largest gastric cancer group (53%). The incidence of lower oesophageal cancer increased between 1998 and 2002 and remained stable thereafter. The incidence of cancer of the cardia, non-cardia stomach, and stomach with an unspecified anatomical site declined over the 10 year period. Both lower oesophageal and cardia cancers had a much higher incidence in males compared with females (M:F 4:1). The incidence was also higher in the most deprived quintiles for all six cancer groups. Survival was poor in all sub-groups with 1 year survival ranging from 14.8-40.8% and 5 year survival ranging from 3.7-15.6%. CONCLUSIONS: An increased focus on prevention and early diagnosis, especially in deprived areas and in males, is required to improve outcomes for these cancers. Improved recording of tumour site, stage and morphology and the evaluation of focused early diagnosis programmes are also needed. The poor long-term survival reinforces the need for early detection and multidisciplinary care

Atomistic characterization of the active-site solvation dynamics of a model photocatalyst

The interactions between the reactive excited state of molecular photocatalysts and surrounding solvent dictate reaction mechanisms and pathways, but are not readily accessible to conventional optical spectroscopic techniques. Here we report an investigation of the structural and solvation dynamics following excitation of a model photocatalytic molecular system [Ir-2(dimen)(4)](2+), where dimen is para-diisocyanomenthane. The time-dependent structural changes in this model photocatalyst, as well as the changes in the solvation shell structure, have been measured with ultrafast diffuse X-ray scattering and simulated with Born-Oppenheimer Molecular Dynamics. Both methods provide direct access to the solute-solvent pair distribution function, enabling the solvation dynamics around the catalytically active iridium sites to be robustly characterized. Our results provide evidence for the coordination of the iridium atoms by the acetonitrile solvent and demonstrate the viability of using diffuse X-ray scattering at free-electron laser sources for studying the dynamics of photocatalysis.1