EFFECTS OF SLURRY TREATMENTS ON GASEOUS EMISSIONS FROM STORAGE AND EVALUATION OF MODELS TO PREDICT AMMONIA RELEASE

Liquid manure storage facilities are sources of methane (CH4), nitrous oxide (N2O) and ammonia (NH3) emissions. CH4 and N2O are relevant greenhouse gases in terms of climate change because of their strong absorption of infrared radiation. NH3 causes various environmental problems, such as odour, eutrophication, acidification of soils and atmospheric particulate matter formation. To mitigate the effect of these emissions on the environment, many guidelines and regulations have been established by governments in various countries. Mitigation options during storage have been proposed, but they are not always easy to be implemented and their adoption in some areas, including Italy, is limited. Furthermore, the introduction of new slurry treatment technologies brings new challenges that require a better knowledge of their effect on the emissions during subsequent storage of the treated manure. This is particularly relevant also in the context of emission inventories, which aim to establish the state of implementation of environmental policies. The research carried out aims to improve the knowledge about the effect on emissions of some slurry management techniques. The activities carried out can be divided in two main groups: 1) Experimental activities a) Pilot scale experiments in controlled temperature conditions which aim to study comparatively the emission and the chemical evolution of treated and untreated slurries during one month storage. In particular it was evaluate how mechanical separation and anaerobic digestion affect NH3 and greenhouse gas emissions from the storage. The experimental plan was designed in order to apply mechanical separation on untreated slurries and digestates and to consider different typologies of slurries, whose characteristics can be considered representative of the average for the region considered. b) Pilot scale experiments in field conditions which aim to study the effect on NH3 and greenhouse emissions of the following treatments and mitigation option: b.1) mechanical separation b.2) application of a coat of clay granules on slurry surface b.3) acidification with sulphuric acid Activities a) and b.1) were carried out at the experimental farm of Landriano (Italy) while Experiments b.2) and b.3) took place at Rothamsted Research Center (UK). The methods used for gas measurement in all experimentations are based on dynamic chamber technique, while the effective nutrient losses have been determined by chemical analyses. 2) Modelling activity: the overall objective of this activity was to identify and calibrate some models, pre-existing in literature, to simulate ammonia emission factors from different storage conditions, suitable over a range of slurry chemical and physical properties. Therefore, 13 different models have been evaluated and a calibration procedure was set using the data obtained in the experimental activities in order to find the best prediction models for each storage condition considered. The main results obtained from experimental activities were the following: \u2022 Mechanical separation can cause a significant increase (up to 85%) of ammonia e nitrous oxide emission during storage: the first one is related to the presence of the liquid fraction while the second is mainly caused by the solid fraction \u2022 Anaerobic digestion can also increment significantly nitrogen losses up to 45 %, but at the same time it represents a treatment that can effectively reduce methane emissions during storage of digestate \u2022 Handling operation have to be carefully considered: increments of nitrogen and carbon losses were observed from mixed slurries. Furthermore it was found that when slurries are mixed, the main factors influencing nitrogen emissions are the TAN concentration and the TAN/TKN ratio. After mixing, the unseparated slurries were associated with higher NH3 emission factors \u2022 Floating clay granules proved to be a very effective NH3 (mean reduction 72 %) mitigation technique but had no significant effect on CH4 emission from pig slurry \u2022 Acidification of cattle slurry proved to be a very effective mitigation technique for both CH4 (mean reduction of 88 %) and NH3 (up to 100% when pH is kept below 5) \u2022 The derivation of country-specific emission factors for pig and cattle slurries in a revised inventory approach need to take into account duration and temperature of storage In general, the results obtained from the experimental activity carried out can be used to estimate the variations of the emissions during storage induced by treatments or mitigation techniques. It is thus possible to quantify the reduction of emissions that can be obtained if best practices are applied with reference to the standard techniques. On the other side, the emissions from the standard technique can be based on models in order to consider the manure characteristics and the local conditions, as demonstrated by the results in the assessment of model to estimate ammonia emissions. In particular models have proved to be very helpful instruments to predict ammonia emission factors in different storage conditions. In some cases, they can also evaluate the effect of a treatment when the latter influence the input variables of the model. In conclusion the use and evaluation of models coupled with the study of slurry treatment effects is advisable for an improved inventory approach and to develop operational guidelines for improved manure management practices to reduce environmental impacts. Further research is necessary to improve models and to better understand the effect of some treatments techniques on emissions. Specific experimentations have to be set in order to validate the models and, at the same time, a wider assessment of treatments across different slurry types is advisable to provide robust values of emission factors, which are the base for a \u201cgood\u201d model development

Effect of a biological additive on nitrogen losses from pig slurry during storage

Additives applied to animal manure slurries can affect the chemical composition and the biological processes of slurries during storage, with possible improvement of their management and reduction of environmental problems. Some new formulations are marketed claiming a nitrogen (N) removal effect due to denitrification, with the consequence of a reduced N content in the manure after storage. This study evaluated the effects of one of these commercial additives (BACTYcomplex) on slurry characteristics and N losses at a commercial piggery. The additive was applied to four different sectors of the piggery, each with an independent under-floor slurry pit; four other sectors served as controls without treatment. Pits were emptied every 4 wk, and the manure was analyzed for total and ammonia-N and total and volatile solids. Slurry samples from the last month of the on-farm assessment were removed and stored thermostatically in vessels external to the piggery. A subsample of slurry that was treated with the additive at the piggery was treated with an additional dose of additive at the beginning of long-term storage. The additive did not change the composition of the slurry during in-house storage (4 wk duration). During the 155 d of external thermostatic storage, the total solids content of treated slurry was reduced by 18% compared with control slurry, but the N content and composition of treated slurry was unaffected. The additive had a positive effect in accelerating the stabilization of the slurry but did not modify N losses

Nutrient losses during winter and summer storage of separated and unseparated digested cattle slurry

Management factors affect nutrient loss during animal manure slurry storage in different ways. We conducted a pilot-scale study to evaluate carbon (C) and nitrogen (N) losses from unseparated and digested dairy slurry during winter and summer storage. In addition to season, treatments included mechanical separation of digestate into liquid and solid fractions and bimonthly mixing. Chemical analyses were performed every 2 wk for the mixed materials and at the start and end of storage for unmixed materials. The parameters examined allowed us to estimate C and N losses and examine the factors that determine these losses as well as emission patterns. Gas measurements were done every 2 wk to determine the main forms in which gaseous losses occurred. To evaluate the effect of separation, measured losses and emissions of separated liquid and solid fractions were mathematically combined using the mass separation efficiency of the mechanical separator. Nutrient losses were mainly affected by climatic conditions. Losses of C (up to 23%) from unseparated, unmixed digestate and of N (38% from combined separated fractions and from unseparated digestate) were much greater in summer than in winter, when C and N losses were < 7%. Mixing tended to significantly increase N losses (P < 0.1) only in winter. Mechanical separation resulted in lower GHG emissions from combined separated fractions than from unseparated digestate. Results indicate that to maximize the fertilizer value of digested slurry, dairy farmers must carefully choose management practices, especially in summer. For separated digestates, practices should focus on storage of the liquid fraction, the major contributor of C and N losses (up to 64 and 90% of total losses, respectively) in summer. Moreover, management practices should limit NH3, the main form of N losses (up to 99.5%)

A farm-scale pilot plant for biohydrogen and biomethane production by two-stage fermentation

Hydrogen is considered one of the possible main energy carriers for the future, thanks to its unique environmental properties. Indeed, its energy content (120 MJ/kg) can be exploited virtually without emitting any exhaust in the atmosphere except for water. Renewable production of hydrogen can be obtained through common biological processes on which relies anaerobic digestion, a well-established technology in use at farm-scale for treating different biomass and residues. Despite two-stage hydrogen and methane producing fermentation is a simple variant of the traditional anaerobic digestion, it is a relatively new approach mainly studied at laboratory scale. It is based on biomass fermentation in two separate, seuqential stages, each maintaining conditions optimized to promote specific bacterial consortia: in the first acidophilic reactorhydrogen is produced production, while volatile fatty acids-rich effluent is sent to the second reactor where traditional methane rich biogas production is accomplished. A two-stage pilot-scale plant was designed, manufactured and installed at the experimental farm of the University of Milano and operated using a biomass mixture of livestock effluents mixed with sugar/starch-rich residues (rotten fruits and potatoes and expired fruit juices), afeedstock mixture based on waste biomasses directly available in the rural area where plant is installed. The hydrogenic and the methanogenic reactors, both CSTR type, had a total volume of 0.7m3 and 3.8 m3 respectively, and were operated in thermophilic conditions (55 2 °C) without any external pH control, and were fully automated. After a brief description of the requirements of the system, this contribution gives a detailed description of its components and of engineering solutions to the problems encountered during the plant realization and start-up. The paper also discusses the results obtained in a first experimental run which lead to production in the range of previous laboratory results, with a typical hydrogen and methane specific productivity of 2.2 and 0.5 Nm3/m3reactor per day, in the first and second stage of the plant respectively. At our best knowledge, this plant is one of the very first prototypes producing biohydrogen at farm scale, and it represents a distributed, small scale demonstration to obtain hydrogen from renewable waste-sources

Nitrogen removal from digested slurries using a simplified ammonia stripping technique

This study assessed a novel technique for removing nitrogen from digested organic waste based on a slow release of ammonia that was promoted by continuous mixing of the digestate and delivering a continuous air stream across the surface of the liquid. Three 10-day experiments were conducted using two 50-L reactors. In the first two, nitrogen removal efficiencies were evaluated from identical digestates maintained at different temperatures (30\ub0C and 40\ub0C). At the start of the first experiment, the digestates were adjusted to pH 9 using sodium hydroxide, while in the second experiment pH was not adjusted. The highest ammonia removal efficiency (87%) was obtained at 40\ub0C with pH adjustment. However at 40\ub0C without pH adjustment, removal efficiencies of 69% for ammonia and 47% for total nitrogen were obtained. In the third experiment two different digestates were tested at 50\ub0C without pH adjustment. Although the initial chemical characteristics of the digestates were different in this experiment, the ammonia removal efficiencies were very similar (approximately 85%). Despite ammonia removal, the pH increased in all experiments, most likely due to carbon dioxide stripping that was promoted by temperature and mixing. The technique proved to be suitable for removing nitrogen following anaerobic digestion of livestock manure because effective removal was obtained at natural pH ( 488) and 40\ub0C, common operating conditions at typical biogas plants that process manure. Furthermore, the electrical energy requirement to operate the process is limited (estimated to be 3.8kWhm-3digestate). Further improvements may increase the efficiency and reduce the processing time of this treatment technique. Even without these advances slow-rate air stripping of ammonia is a viable option for reducing the environmental impact associated with animal manure management

Digenic inheritance of human primary microcephaly delineates centrosomal and non-centrosomal pathways.

Primary microcephaly (PM) is characterized by a small head since birth and is vastly heterogeneous both genetically and phenotypically. While most cases are monogenic, genetic interactions between Aspm and Wdr62 have recently been described in a mouse model of PM. Here, we used two complementary, holistic in vivo approaches: high throughput DNA sequencing of multiple PM genes in human patients with PM, and genome-edited zebrafish modeling for the digenic inheritance of PM. Exomes of patients with PM showed a significant burden of variants in 75 PM genes, that persisted after removing monogenic causes of PM (e.g., biallelic pathogenic variants in CEP152). This observation was replicated in an independent cohort of patients with PM, where a PM gene panel showed in addition that the burden was carried by six centrosomal genes. Allelic frequencies were consistent with digenic inheritance. In zebrafish, non-centrosomal gene casc5 -/- produced a severe PM phenotype, that was not modified by centrosomal genes aspm or wdr62 invalidation. A digenic, quadriallelic PM phenotype was produced by aspm and wdr62. Our observations provide strong evidence for digenic inheritance of human PM, involving centrosomal genes. Absence of genetic interaction between casc5 and aspm or wdr62 further delineates centrosomal and non-centrosomal pathways in PM

Diagnosis of arrhythmogenic cardiomyopathy: The Padua criteria.

The original designation of "Arrhythmogenic right ventricular (dysplasia/) cardiomyopathy"(ARVC) was used by the scientists who first discovered the disease, in the pre-genetic and pre-cardiac magnetic resonance era, to describe a new heart muscle disease predominantly affecting the right ventricle, whose cardinal clinical manifestation was the occurrence of malignant ventricular arrhythmias. Subsequently, autopsy investigations, genotype-phenotype correlations studies and the increasing use of contrast-enhancement cardiac magnetic resonance showed that the fibro-fatty replacement of the myocardium represents the distinctive phenotypic feature of the disease that affects the myocardium of both ventricles, with left ventricular involvement which may parallel or exceed the severity of right ventricular involvement. This has led to the new designation of "Arrhythmogenic Cardiomyopathy" (ACM), that represents the evolution of the original term of ARVC. The present International Expert Consensus document proposes an upgrade of the criteria for diagnosis of the entire spectrum of the phenotypic variants of ACM. The proposed "Padua criteria" derive from the diagnostic approach to ACM, which has been developed over 30 years by the multidisciplinary team of basic researchers and clinical cardiologists of the Medical School of the University of Padua. The Padua criteria are a working framework to improve the diagnosis of ACM by introducing new diagnostic criteria regarding tissue characterization findings by contrast-enhanced cardiac magnetic resonance, depolarization/repolarization ECG abnormalities and ventricular arrhythmia features for diagnosis of the left ventricular phenotype. The proposed diagnostic criteria need to be further validated by future clinical studies in large cohorts of patients

Background matching in the brown shrimp Crangon crangon : adaptive camouflage and behavioural-plasticity

A combination of burrowing behaviour and very efficient background matching makes the brown shrimp Crangon crangon almost invisible to potential predators and preys. This raises questions on how shrimp succeed in concealing themselves in the heterogeneous and dynamic estuarine habitats they inhabit and what type of environmental variables and behavioural factors affect their colour change abilities. Using a series of behavioural experiments, we show that the brown shrimp is capable of repeated fast colour adaptations (20% change in dark pigment cover within one hour) and that its background matching ability is mainly influenced by illumination and sediment colour. Novel insights are provided on the occurrence of non-adaptive (possibly stress) responses to background changes after long-time exposure to a constant background colour or during unfavourable conditions for burying. Shrimp showed high levels of intra- and inter-individual variation, demonstrating a complex balance between behavioural-plasticity and environmental adaptation. As such, the study of crustacean colour changes represents a valuable opportunity to investigate colour adaptations in dynamic habitats and can help us to identify the mayor environmental and behavioural factors influencing the evolution of animal background matching