Land Spreading Research Articles

Improving manure nutrient management towards sustainable agricultural intensification in China

Traditionally farmers in China have relied on organic manures to build the organic matter content in soil and to fertilise crops for both human and livestock consumption. However, with requirements to increase food production, the use of relatively cheap inorganic fertilisers has increased, and manure nutrients are not always used to their potential. In addition, farms of all sizes and even biogas plants, often lack the basic infrastructure to manage manures; poor containment facilities often result in untreated manures being discharged directly into watercourses, whilst transportation of manures to the field and land spreading is often not mechanised and relies on availability of suitable labour. There is already clear evidence of overuse of nutrients in some parts of China and this is causing undesirable impacts on the environment. With the increasing demand for livestock products from a burgeoning population and changes in dietary preferences towards animal protein, greater quantities of manure nutrients will be generated in the next twenty years, especially in peri-urban concentrated animal feeding operations and intensive farms. It is essential that China addresses the infrastructural, research and communication challenges to ensure that manures are integrated into nutrient planning at the field, farm and regional level to safeguard the environment, reduce the requirement for inorganic fertiliser production and use, and improve farmer incomes. This paper reviews the current manure management practices, both nationally and, where appropriate, at a regional scale, and assesses what barriers currently prevent efficient manure nutrient utilisation in China. We then address the future challenges for manure nutrient management in China, before summarising key gaps in knowledge and communication with implications for research and policy.

Geomatics monitoring and models of the insalination of the freshwaters phenomenon along the Pisan coastline

The strip of dunes on the coast of Pisa is home to a major aquifer which helps to limit the intrusion of sea water, thus preventing its spread inland. In the last decade, due to a decrease in meteoric precipitation as well as the reckless increase in the exploitation of surface water resources, this barrier has been significantly reduced, with subsequent repercussions on the environment and on local activities. The salinization of coastal aquifers along the Pisa coastline is related to the procession of the salt wedge (i.e., salt degradation). The problem is serious. It renders groundwater unusable for drinking, unless expensive desalination plants are used. Salt water also hampers agriculture, leading to the loss of profitable crops that are poorly resistant to salinity, to be replaced by less profitable but more resistant ones. This thus results in ecological and environmental problems due to the degradation to coastal pinewoods. Given the potential harm involved, a monitoring network of the aquifer water table was set up by the Department for Environment of the Municipality of Pisa, in order to monitor its evolution. To provide a framework for more detailed knowledge of the phenomenon, and to be made available to users and local authorities, the databases derived from the various monitoring activities need to be univocally and correctly georeferenced. We present some of the issues related to saltwater intrusion, how it can be monitored, as well as the methodologies—Global Navigation Satellite System (GNSS), LIght Detection And Ranging (LiDAR), and traditional approaches—used to define the elevation of the wells. We assess the level of precision that could be obtained and the requirements in terms of time, personnel, and equipment.

Pelleting properties and pellet quality of apple pomace

Apple pomace (AP) is the main by-product of apple juice production. It is a residue after pressing of apples for juice extraction. AP is an organic material, with high moisture and sugar content, therefore its direct disposal on landfills or land spreading causes serious environmental pollution. One of the solutions for further exploitation of AP could be its utilization as animal feed. However, fresh AP is quite perishable, and it must be preserved in order to be stored and used over a long period of time. The aim of this research was to investigate the possibility to transform AP to a stabile form which would be acceptable for feed manufacturers in terms of stability, storage and handling. For this purpose, pelleting process was used and pelleting properties of AP were evaluated. Before pelleting, dried AP was divided into three batches, which were conditioned only by water addition in order to achieve different moisture contents of the material: 10% of moisture for the first batch, 13% for the second batch and 16% for the third batch. According to the obtained values for Pellet Durability Index (PDI) and pellet hardness, pellet quality for all examined AP batches was very high. Increased moisture content of AP led to the reduction in energy consumption of the pellet press, thus providing energy saving in the pelleting process. Pelleting process also caused strong increase of AP bulk density which is positive in terms of transportation and storage.

Changes in Soil Macronutrients after a Long-Term Application of Olive Mill Wastewater

The land spreading of olive mill wastewater (OMW) derived from olive oil production can represent a suitable option to enrich and maintain agriculture soils under south Mediterranean climates. Therefore, OMW spreading field may represent a low cost contribution to crop fertilization and soil amendment. The main objective of this study was to investigate the long-term effects of raw OMW application on soil macronutrients and phenolic compounds dynamics. The results showed that regular application of three doses: 50, 100 and 200 m3&middotha-1 of OMW for nine successive years increased the soil electrical conductivity significantly (p ≤ 0.05%) with the increase of OMW rates at the depth 0 - 20 cm. The pH variations were not detected after ten months of the spreading date. Furthermore, soil sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) values were substantially affected by OMW salinity. The soil organic matter (SOM) increased from 0.068% observed for the control sample to 0.2%, 0.34% and 0.48%, respectively, with the increase of OMW rate in the top layer (0 - 20 cm). The potassium, phosphorus and nitrogen increased gradually with the OMW application dose. The Ca2+ contents on soil decreased with the spreading of OMW rate, as referred to control. In addition, the phenolic compounds variations were not proportional to doses applied and its levels remained high as compared with the control essentially on top layers (0 - 40 cm). This practice should be beneficial to organic farming and is an alternative solution to direct spreading of raw OMW on soil.

Ecotoxicological assessment of organic wastes spread on land: Towards a proposal of a suitable test battery

The land spreading of organic wastes in agriculture is a common practice in Europe, under the regulation of the Directive 86/278/EEC. One of the objectives of this Directive is to prevent harmful effects of organic wastes on soil, plants and animals. Despite this regulatory framework, there is still a lack of harmonized ecotoxicological test strategy to assess the environmental hazard of such wastes.The aim of this study was to provide a first step towards the a priori ecotoxicological assessment of organic wastes before their land use. For that purpose, nine different organic wastes were assessed using direct (i.e. terrestrial tests) and indirect (i.e. tests on water eluates) approaches, for a total of thirteen endpoints. Then, multivariate analyzes were used to discriminate the most relevant test strategy, among the application rates and bioassays used.From our results, a draft of test strategy was proposed, using terrestrial bioassays (i.e. earthworms and plants) and a concentration range between one and ten times the recommended application rates of organic wastes.

Ammonia volatilization after surface application of laying-hen and broiler-chicken manures.

Ammonia (NH) losses after field application of animal manure are affected by manure characteristics. The objectives of this study were to quantify NH losses from poultry manures obtained from varied handling and storage systems commonly found in eastern Canada and to relate NH emissions to manure characteristics. We measured NH volatilization using wind tunnels for 22 d after soil-surface application of seven solid poultry manures originating from farms varying in production type (laying hens and broiler chickens) and in storage duration and conditions. Cumulative emissions (2.7-7.0 g NH-N m) accounted for 13.6 to 35.0% of the total N applied and 51 to 84% (mean, 70%) of the sum of ammoniacal N, urea N, and uric acid N applied (TAUA). On average, 20% of these losses occurred during the first 4.5 h after application for manures that were not dried in the barn shortly after excretion. Production type and storage durations could not explain differences in NH volatilization between manures. Volatilization losses were linearly related to manure dry matter and to manure-derived NH-N, but sources of N changed with time after application. During the first 7 d, variations in total ammoniacal N applied (TANA) among manures explained most of the variations in cumulative NH losses ( = 0.85 after 26 h and 0.92 after 7 d). After a simulated rainfall (5 mm) on Day 7 that stimulated the decomposition of uric acid in manures, TAUA rather than TANA was related to cumulative emissions ( = 0.77 after 14 and 22 d). Our results indicate that reliable estimates of NH volatilization after land spreading of poultry manures should be based not only on TANA but also on NH-N derived from the decomposition of uric acid, that volatilization losses reported in the literature (including the present study) averaged 50% of TAUA, and that estimates for a given situation also need to account for local environmental conditions.

Ammonia and greenhouse gases emission from impermeable covered storage and land application of cattle slurry to bare soil

Handling a large volume of livestock wastes in intensive farm systems could lead to adverse environmental effects, such as excessive load of nutrients to the soil and gaseous losses into the atmosphere. Land spreading of animal manure is one of the sources of ammonia (NH3) volatilization in Europe. Livestock emissions from manure management in the form of greenhouse gases (GHG), i.e., methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2O), amount to 15% of the total agricultural emissions. Therefore, it is important to address gas emissions during storage and following slurry land application to reduce the swapping of emissions from one stage of the manure management continuum to the next one. In this study, NH3 and GHG emissions were estimated from flexible bag storage and following cattle slurry band spreading and incorporation to soil. For this, the mass-balance integrated horizontal flux (IHF) technique was used based on NH3 concentration measurements from masts supporting passive flux samplers (PFS) at different heights and GHG concentrations from grab air samples. Furthermore, the backward Lagrangian stochastic (bLS) technique was compared with NH3 emission estimates from the IHF technique along the manure management continuum. On the whole, NH3 and GHG emissions were considered low from the flexible bag storage compared to those from uncovered lagoons reported in the literature. Slurry removal from storage led to higher NH3 and N2O emissions, representing 73% and 75% of total loss in storage, respectively. After slurry band application to soil, NH3 emission peaked within the first 10h. In overall, lower NH3 emissions were registered in land in the current study in comparison with studies testing broadcast application. Slurry land application led to higher CO2 and N2O emissions than covered storage, contributing to 75% and 99% of total emissions, respectively. Regarding results from the bLS technique, NH3 estimates were lower than expected, possibly due to the low emissions found following NH3 abatement strategies carried out in storage and fertilization stages, and insufficient plot coverage by the PFS under changing wind directions. Under occasional NH3 emissions due to manure management operations, the use of multiple downwind points in bLS resulted in more accurate results and better plot coverage compared to a single point. Average NH3 concentration and wind direction within 24h could result in uncertain bLS estimates under changing wind directions. Overall, the flexible bag storage was an effective method of gas emission mitigation in outdoor slurry storage. Slurry band spreading to bare soil lowered NH3 emissions, but a delay in incorporating slurry to soil could have reduced the efficacy of incorporation on NH3 abatement.

Changes in home range sizes and population densities of carnivore species along the natural to urban habitat gradient

AbstractWith rapid development and the spread of urbanized land, there is an increasing need to understand species' responses to urban conditions. Carnivores are considered to be sensitive to urbanization; however, there is ample evidence that some carnivore species successfully inhabit urban areas, and human‐modified habitats have recently been recognized as an important refuge for several species.Despite the increasing number of studies on urban carnivore ecology, no comprehensive cross‐species comparisons have been made in order to assess the effects of urbanization on the spatial ecology of carnivores and their population densities. Such a review could provide interesting insight into how some carnivore species respond to increasing urbanization. Specifically, we examine changes in population density and home range size of eight carnivore species that occur along the natural–urban environmental gradient.Using data from 411 articles, we provide evidence that the home range size of carnivores decreases in six out of eight species, and population density increases in three out of six species along the natural–urban habitat gradient. The density‐dependent pattern of variation in home range size is consistent in all species studied.Our results emphasize the remarkable ability of some carnivore species to adapt to novel environments through their behavioural flexibility and life history adaptations. We outline ideas for future research that could be adopted in addressing this phenomenon, namely comparative approaches and detailed studies of biotic and abiotic conditions along natural–urban gradients.

Study of Utilisation of Hypo Sludge in High Performance Concrete

Population scenario came towards India by means of increasing industries. More than 200 million tonnes of agriculture and industrial waste is produced every year .Hypo sludge produced by mills is posing major economic and environmental problem .The main recycling and disposal routes for paper sludge includes land spreading over croplands and disposal into farmlands or to landfills which gives rise to contamination of soil. Since energy plays a crucial role in growth of developing countries like India and with low availability of non-renewable energy resources linked with the requirement of large quantities of energy for building materials like cement the re-use of by products or wastes produced in nay industrial process is a high priority today and one way of recycling these materials is to seek concrete applications with compatible use and the same characteristics. The published work shows that paper industry is one of the better sectors to get environmental objectives since raw materials are renewable, its products and wastes are recyclable and production processes are capable of technological improvements to protect the environment. The paper presents the overview of published work on utilisation of hypo sludge with high performance concrete, exploring its pozzolanic properties, mechanical properties like compressive strength, splitting strength, modulus of elasticity, water absorption test, sorptivity and cost analysis are presented.

Hygienization performances of innovative sludge treatment solutions to assure safe land spreading.

The present research aims at the evaluation of the hygienization performances of innovative sludge treatment processes applied for the separated treatment of secondary sludge. Namely, two digestion pretreatments (sonication and thermal hydrolysis) and two sequential biological processes (mesophilic/thermophilic and anaerobic/aerobic digestion) were compared to the mesophilic (MAD) and thermophilic anaerobic digestion (TAD). Microbial indicators (Escherichia coli, somatic coliphages and Clostridium perfringens spores) and pathogens (Salmonella and enteroviruses), which show different resistances to treatment processes, were monitored in untreated and treated sludge. Overall, microbial load in secondary sludge was shown to be similar or lower than previously reported in literature for mixed sludge. Notably, the anaerobic/aerobic digestion process increased the removal of E. coli and somatic coliphages compared to the simple MAD and always achieved the hygienization requirement (2-log-unit removal of E. coli) proposed by EU Commission in the 3rd Working Document on sludge (April 2000) for the use of treated sludges in agriculture with restriction on their application. The microbial quality limits for the unrestricted use of sludge in agriculture (no Salmonella in 50 g wet weight (WW) and E. coli <500 CFU/g) were always met when thermal digestion or pretreatment was applied; however, the required removal level (6-log-unit removal of E. coli) could not be assessed due to the low level of this microorganism in raw sludge. Observed levels of indicator removal showed a higher resistance of viral particles to thermal treatment compared with bacterial cells and confirmed the suitability of somatic coliphages as indicators in thermal treatment processes.

Behavior of Heavy Metals during Fluidized Bed Combustion of Poultry Litter

In this study, we have examined the behavior of heavy metals during fluidized bed combustion of poultry litter. Heavy metals examined include As, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, V, and Zn. Solid and gaseous streams were analyzed and compared with relevant guidelines to determine the potential environmental impact of combustion and subsequent land spreading or landfill of the resulting ash. The majority of heavy metals were associated with the solid ash fraction, with low gaseous emissions. Pb and As were concentrated in the fine baghouse ash (160 °C) due to their volatility. The remaining heavy metals, excluding Cd, were enriched in the heat exchangers and cyclone, where flue gas temperatures ranged from 580 to 220 °C. Under the waste acceptance criteria, all samples of process ash, excluding bed ash, exceeded the limits for nonhazardous landfill waste, as a result of high levels of water-soluble Cr. Water-soluble Cr indicated the presence of Cr(VI), and its presence was confirmed using X-ray absorpti...

Addition of Straw or Sawdust to Mitigate Greenhouse Gas Emissions from Slurry Produced by Housed Cattle: A Field Incubation Study

The use of housed wintering systems (e.g., barns) associated with dairy cattle farming is increasing in southern New Zealand. Typically, these wintering systems use straw or a woodmix as bedding material. Ammonia (NH) and greenhouse gas (GHG) emissions (nitrous oxide [NO] and methane [CH]) associated with storage of slurry + bedding material from wintering systems is poorly understood. A field incubation study was conducted to determine such emissions from stored slurry where bedding material (straw and sawdust) was added at two rates and stored for 7 mo. During the first 4 mo of storage, compared with untreated slurry, the addition of sawdust significantly reduced NH and CH emissions from 29 to 3% of the initial slurry nitrogen (N) content and from 0.5 to <0.01% of the initial slurry carbon (C) content. However, sawdust enhanced NO emissions to 0.7% of the initial slurry-N content, compared with <0.01% for untreated slurry. Straw generally had an intermediate effect. Extending the storage period to 7 mo increased emissions from all treatments. Ammonia emissions were inversely related to the slurry C:N ratio and total solid (TS) content, and CH emissions were inversely related to slurry TS content. Mitigation of GHG emissions from stored slurry can be achieved by reducing the storage period as much as possible after winter slurry collection, providing ground conditions allow access for land spreading and nutrient inputs match pasture requirements. Although adding bedding material can reduce GHG emissions during storage, increased manure volumes for carting and spreading need to be considered.

A regional mass balance model based on total ammoniacal nitrogen for estimating ammonia emissions from beef cattle in Alberta Canada

Animal feeding operations are primary contributors of anthropogenic ammonia (NH3) emissions in North America and Europe. Mathematical modeling of NH3 volatilization from each stage of livestock manure management allows comprehensive quantitative estimates of emission sources and nutrient losses. A regionally-specific mass balance model based on total ammoniacal nitrogen (TAN) content in animal manure was developed for estimating NH3 emissions from beef farming operations in western Canada. Total N excretion in urine and feces was estimated from animal diet composition, feed dry matter intake and N utilization for beef cattle categories and production stages. Mineralization of organic N, immobilization of TAN, nitrification, and denitrification of N compounds in manure, were incorporated into the model to account for quantities of TAN at each stage of manure handling. Ammonia emission factors were specified for different animal housing (feedlots, barns), grazing, manure storage (including composting and stockpiling) and land spreading (tilled and untilled land), and were modified for temperature. The model computed NH3 emissions from all beef cattle sub-classes including cows, calves, breeding bulls, steers for slaughter, and heifers for slaughter and replacement. Estimated NH3 emissions were about 1.11 × 105 Mg NH3 in Alberta in 2006, with a mean of 18.5 kg animal−1 yr−1 (15.2 kg NH3–N animal−1 yr−1) which is 23.5% of the annual N intake of beef cattle (64.7 kg animal−1 yr−1). The percentage of N intake volatilized as NH3–N was 50% for steers and heifers for slaughter, and between 11 and 14% for all other categories. Steers and heifers for slaughter were the two largest contributors (3.5 × 104 and 3.9 × 104 Mg, respectively) at 31.5 and 32.7% of total NH3 emissions because most growing animals were finished in feedlots. Animal housing and grazing contributed roughly 63% of the total NH3 emissions (feedlots, barns and pastures contributed 54.4, 0.2 and 8.1% of total emissions, respectively.). Manure storage (composting and stockpiling) and land spreading contributed 23 and 14% of the total emissions, respectively. Parameters from this TAN-based mass balance model will be incorporated into the HOLOS model – a farm-level greenhouse gas calculator.

Electricity from poultry manure: a cleaner alternative to direct land application

The oversupply of organic fertilizers causes an urgent need for alternative treatments of manure. CO2 neutral electricity is produced from poultry manure, a renewable fuel which is relatively dry and has a heating value of 6–8 MJ/kg. The electricity production from manure saves emissions from fossil fuel combustion, resulting in a reduced environmental impact in the impact category climate change. Moreover, as manure contains a large amount of ammoniacal N, and due to nitrification and denitrification processes, land spreading of poultry manure causes larger emissions of NH3, N2O and NOx than combustion. Electricity production from manure therefore outperforms land spreading in the impact categories terrestrial acidification, particulate matter formation, marine eutrophication and photochemical oxidant formation. The fluidized bed combustor of BMC in the Netherlands generates zero waste, as the ash is recovered as a PK fertilizer, which is odorless, dry, sterile and has a lower mass and volume than the manure, making it more suitable for export to regions with a high P demand. The ash does however cause technological problems, such as agglomeration and deposition.

REVIEW ON NATURAL METHODS FOR WASTE WATER TREATMENT

In Ethiopia, the most common method of disposal of waste water is by land spreading. This treatment method has numerous problems, namely high labor requirements and the potential for eutrophication of surface and ground waters. Constructed wetlands are commonly used for treatment of secondary municipal wastewaters and they have been gaining popularity for treatment of agricultural wastewaters in Ethiopia. Intermittent sand filtration may offer an alternative to traditional treatment methods. As well as providing comparable treatment performance, they also have a smaller footprint, due to the substantially higher organic loading rates that may be applied to their surfaces. This paper discusses the performance and design criteria of constructed wetlands for the treatment of domestic and agricultural wastewater, and sand filters for the treatment of domestic wastewater. It also proposes sand filtration as an alternative treatment mechanism for agricultural wastewater and suggests design guidelines.

REVIEW ON NATURAL METHODS FOR WASTE WATER TREATMENT

In Ethiopia, the most common method of disposal of waste water is by land spreading. This treatment method has numerous problems, namely high labor requirements and the potential for eutrophication of surface and ground waters. Constructed wetlands are commonly used for treatment of secondary municipal wastewaters and they have been gaining popularity for treatment of agricultural wastewaters in Ethiopia. Intermittent sand filtration may offer an alternative to traditional treatment methods. As well as providing comparable treatment performance, they also have a smaller footprint, due to the substantially higher organic loading rates that may be applied to their surfaces. This paper discusses the performance and design criteria of constructed wetlands for the treatment of domestic and agricultural wastewater, and sand filters for the treatment of domestic wastewater. It also proposes sand filtration as an alternative treatment mechanism for agricultural wastewater and suggests design guidelines.

Dimenzionisanje cevovodno-injektorskog sistema za raspodelu tečnog stajnjaka

Increasingly, there are pressures on agriculture to reduce emissions of ammonia to the atmosphere, because of concerns about environmental impact.The land spreading of animal manures accounts for approximately one-third of the total NH 3 emissions from agriculture, so there has been much interest in the development of abatement measures in this area. Piping systems for parallel distribution and injection of liquid manure to arable land is an effective way of using its nutrients and odors during distribution. However, in despite the high purchase price, in our conditions, these systems are expensive to install and operationally complex. A decision of the possible application of this system requires knowledge of complex economic, land, microclimatic, technical and technological informations. Accordingly, this paper provides a simplified graphical method for proper selection of variants of pipeline systems for transport and injection of liquid manure as base assumptions when making a decision: 'Yes or No!'. Of particular interest is the reduction of ammonia emissions, as an important carrier of readily available nitrogen for plants and on the other hand as very dangerous environmental pollutants. Compared to conventional systems of the surface distribution of liquid manure, new techniques developed its injection result in the reduction of ammonia emissions in the approximate range of 70-95%. Taken together with the results of other research, it is apparent that a range of ambient, soil and crop conditions, as well as operational factors, will influence the effectiveness of the NH 3 emission abatement achieved using these techniques and would justify further research. An economic evaluation of using the new application techniques, together with a detailed assessment of factors influencing any agronomic benefits, are areas which would benefit from further study.

Cold season ammonia emissions from land spreading with anaerobic digestates from biogas production

Anaerobic digestates (AD) from biogas production are applied to agricultural land as organic fertilizers, but pose an ammonia (NH3) emission source. However, data about NH3 emissions of cold season AD land spreading is still lacking. Therefore, in the present study NH3 emissions of AD application under winter conditions were determined. AD was applied via trail hoses to a field plot of 27 ha in Northern Germany during the winter with temperatures around the freezing point and partly frozen soil. NH4+ N application rate was, including a preceding urea application, 123 kg NH4+ and urea N ha−1. The NH3 volatilization was monitored using Open Path Fourier Transform Infrared spectroscopy in combination with a micrometeorological transport model. Cumulative NH3 volatilization during the six day measurements was 17.5 kg NH3 N ha−1 which corresponds to 33.1% of the NH4+ N in applied AD. This NH3 loss is relatively high for low temperature conditions and was most likely caused by the frozen soil restricting AD infiltration.

Biochemical and antiviral activities of enzymatic hydrolysates from different invasive French seaweeds

Proliferations of green, brown and red algae appear in shallow sandy bays in North Brittany (France), and they represent a real economic constraint for the affected communities. In addition to the nuisance for residents and tourist activity, the communities must carry out systematic collection. The collected algae are spread on agricultural land spreading or composted, but these solutions reach their limits rapidly, bringing little added value to the collected algae. Seaweeds are potentially excellent sources of bioactive metabolites that could represent useful leads in the development of new functional ingredients in pharmaceutical and cosmetic industries. The aim of this study was to propose the use of an enzyme-assisted extraction as a tool to improve the extraction efficiency of antiviral compounds from three invasive French seaweeds. We selected the red Solieria chordalis, the green Ulva sp. and the brown Sargassum muticum as models for these experiments. In comparison with water extraction at 50 °C for the same time of treatment, enzymatic hydrolysis increased the yields. The data suggest the potential of enzymatic hydrolysis for producing active fractions in the function of the algal biomass, the behaviour of the cell wall, the selectivity and the action of the enzyme. Enzymatic hydrolysis appeared less effective for polyphenol recovery, but was a promising softer technique for recovering proteins, neutral sugars, uronic acids and sulphate groups. The solvent-free process, higher extraction rate and higher yields, coupled to time-saving and lower cost, make this method economical and sustainable. By using a cell viability assay, all hydrolysate fractions tested were shown to be non-toxic to Vero cells. After 3 days of treatment, no microscopically visible alteration of normal cell morphology was observed even at 500 μg mL−1. S. chordalis extracts have an effective antiviral activity with EC50 between 23.0 and 101.1 μg mL−1 at a multiplicity of infection of 0.001 ID50/cells; 100 % and 98 % cellular protection were obtained for 500 μg mL−1 of hydrolysate extracts carbohydrase C3 and blank, respectively. Other extracts from S. chordalis inhibited viral production less effectively.

Recovery of ammonia in digestates of calf manure through a struvite precipitation process using unconventional reagents

Land spreading of digestates causes the discharge of large quantities of nutrients into the environment, which contributes to eutrophication and depletion of dissolved oxygen in water bodies. For the removal of ammonia nitrogen, there is increasing interest in the chemical precipitation of struvite, which is a mineral that can be reused as a slow-release fertilizer. However, this process is an expensive treatment of digestate because large amounts of magnesium and phosphorus reagents are required. In this paper, a struvite precipitation-based process is proposed for an efficient recovery of digestate nutrients using low-cost reagents. In particular, seawater bittern, a by-product of marine salt manufacturing and bone meal, a by-product of the thermal treatment of meat waste, have been used as low-cost sources of magnesium and phosphorus, respectively. Once the operating conditions are defined, the process enables the removal of more than 90% ammonia load, the almost complete recovery of magnesium and phosphorus and the production of a potentially valuable precipitate containing struvite crystals.