Swedish Institute of Agricultural and Environmental Engineering

Uppsala, Sweden

Swedish Institute of Agricultural and Environmental Engineering

Uppsala, Sweden
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Coppola L.,Marche Polytechnic University | Pilar Castillo M.D.,Swedish Institute of Agricultural and Environmental Engineering | Vischetti C.,Marche Polytechnic University
Pest Management Science | Year: 2011

Background: The composition and properties of a biomixture used in a biobed are decisive for pesticide sorption and degradation. This study was performed to investigate the capability of compost-based substrates in mixtures with citrus peel and vine branch straw and peat-based substrates in mixtures with soil and vine branch straw at different levels in order to degrade isoproturon and bentazone. Results: Dissipation and mineralisation rates of both pesticides were determined, and metabolic activity was followed as respiration. Compost-based substrates showed faster pesticide dissipation in the presence of lignocellulosic materials, as in garden compost and vine branch straw. The increasing content of vine branch straw in peat-based substrates does not seem to affect dissipation of the parent compounds. Low mineralisation rate was observed in all treatments. Conclusion: Higher pesticide degradation was observed in the lignocellulosic substrates, probably because of the development of lignin-degrading microorganisms which have shown to be robust and are able to degrade recalcitrant pesticides. © 2010 Society of Chemical Industry.

Kimming M.,Swedish University of Agricultural Sciences | Sundberg C.,Swedish University of Agricultural Sciences | Nordberg A.,Swedish Institute of Agricultural and Environmental Engineering | Baky A.,Swedish Institute of Agricultural and Environmental Engineering | And 3 more authors.
Biomass and Bioenergy | Year: 2011

Biomass produced on farm land is a renewable fuel that can prove suitable for small-scale combined heat and power (CHP) plants in rural areas. However, it can still be questioned if biomass-based energy generation is a good environmental choice with regards to the impact on greenhouse gas emissions, and if there are negative consequences of using of agricultural land for other purposes than food production. In this study, a simplified life cycle assessment (LCA) was conducted over four scenarios for supply of the entire demand of power and heat of a rural village. Three of the scenarios are based on utilization of biomass in 100 kW (e) combined heat and power (CHP) systems and the fourth is based on fossil fuel in a large-scale plant. The biomass systems analyzed were based on 1) biogas production with ley as substrate and the biogas combusted in a microturbine, 2) gasification of willow chips and the product gas combusted in an IC-engine and 3) combustion of willow chips for a Stirling engine. The two first scenarios also require a straw boiler. The results show that the biomass-based scenarios reduce greenhouse gas emissions considerably compared to the scenario based on fossil fuel, but have higher acidifying emissions. Scenario 1 has by far the best performance with respect to global warming potential and the advantage of utilizing a byproduct and thus not occupying extra land. Scenario 2 and 3 require less primary energy and less fossil energy input than 1, but set-aside land for willow production must be available. The low electric efficiency of scenario 3 makes it an unsuitable option. © 2011 Elsevier Ltd.

Granhall U.,Swedish University of Agricultural Sciences | Welsh A.,Swedish University of Agricultural Sciences | Throback I.N.,Swedish University of Agricultural Sciences | Hjort K.,Södertörn University College | And 2 more authors.
Journal of Industrial Microbiology and Biotechnology | Year: 2010

Paper mills processing recycled paper suffer from biofouling causing problems both in the mill and final product. The total bacterial community composition and identification of specific taxa in the process water and biofilms at the stock preparation and paper machine areas in a mill with recycled paper pulp was described by using a DNA-based approach. Process water in a similar mill was also analyzed to investigate if general trends can be found between mills and over time. Bacterial community profiles, analyzed by terminal-restriction fragment length polymorphism (T-RFLP), in process water showed that the dominant peaks in the profiles were similar between the two mills, although the overall composition was unique for each mill. When comparing process water and biofilm at different locations within one of the mills, we observed a separation according to location and sample type, with the biofilm from the paper machine being most different. 16S rRNA gene clone libraries were generated and 404 clones were screened by RFLP analysis. Grouping of RFLP patterns confirmed that the biofilm from the paper machine was most different. A total of 99 clones representing all RFLP patterns were analyzed, resulting in sequences recovered from nine bacterial phyla, including two candidate phyla. Bacteroidetes represented 45% and Actinobacteria 23% of all the clones. Sequences with similarity to organisms implicated in biofouling, like Chryseobacterium spp. and Brevundimonas spp., were recovered from all samples even though the mill had no process problems during sampling, suggesting that they are part of the natural paper mill community. Moreover, many sequences showed little homology to as yet uncultivated bacteria implying that paper mills are interesting for isolation of new organisms, as well as for bioprospecting. © Society for Industrial Microbiology 2010.

Kimming M.,Swedish University of Agricultural Sciences | Sundberg C.,Swedish University of Agricultural Sciences | Nordberg A.,Swedish University of Agricultural Sciences | Nordberg A.,Swedish Institute of Agricultural and Environmental Engineering | And 4 more authors.
Bioresource Technology | Year: 2011

The agricultural industry today consumes large amounts of fossil fuels. This study used consequential life cycle assessment (LCA) to analyse two potential energy self-sufficient systems for organic arable farms, based on agricultural residues. The analysis focused on energy balance, resource use and greenhouse gas (GHG) emissions. A scenario based on straw was found to require straw harvest from 25% of the farm area; 45% of the total energy produced from the straw was required for energy carrier production and GHG emissions were reduced by 9% compared with a fossil fuel-based reference scenario. In a scenario based on anaerobic digestion of ley, the corresponding figures were 13%, 24% and 35%. The final result was sensitive to assumptions regarding, e.g., soil carbon content and handling of by-products. © 2010 Elsevier Ltd.

Onneby K.,Swedish University of Agricultural Sciences | Hakansson S.,Swedish University of Agricultural Sciences | Pizzul L.,Swedish Institute of Agricultural and Environmental Engineering | Stenstrom J.,Swedish University of Agricultural Sciences
Biodegradation | Year: 2014

The use of pesticides on sandy soils and on many non-agricultural areas entails a potentially high risk of water contamination. This study examined leaching of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) after bioaugmentation in sand with differently formulated and stored Sphingobium sp. T51 and at different soil moisture contents. Dry formulations of Sphingobium sp. T51 were achieved by either freeze drying or fluidised bed drying, with high initial cell viability of 67-85 %. Storage stability of T51 cells was related to formulation excipient/carrier and storage conditions. Bacterial viability in the fluidised bed-dried formulations stored at 25 °C under non-vacuum conditions was poor, with losses of at least 97 % within a month. The freeze-dried formulations could be stored substantially longer, with cell survival rates of 50 %, after 6 months of storage at the same temperature under partial vacuum. Formulated and long-term stored Sphingobium cells maintained their MCPA degradation efficacy and reduced MCPA leaching as efficiently as freshly cultivated cells, by at least 73 % when equal amounts of viable cells were used. The importance of soil moisture for practical field bioaugmentation techniques is discussed. © 2013 Springer Science+Business Media Dordrecht.

Aronsson H.,Swedish University of Agricultural Sciences | Liu J.,Swedish University of Agricultural Sciences | Ekre E.,Swedish Rural economics and Agricultural Society of Halland | Torstensson G.,Swedish University of Agricultural Sciences | Salomon E.,Swedish Institute of Agricultural and Environmental Engineering
Nutrient Cycling in Agroecosystems | Year: 2014

Two crop rotations dominated by spring cereals and grass/clover leys on a clay soil were studied over 2 years with respect to nitrogen (N) and phosphorus (P) leaching associated with pig or dairy slurry application in April, June and October. Leaching losses of total N (TN), total P (TP), nitrate-N and dissolved reactive P (DRP) were determined in separately tile-drained field plots (four replicates). Mean annual DRP leaching after October application of dairy slurry (17 kg P ha-1) to growing grass/clover was 0.37 kg ha-1. It was significantly higher than after October application of pig slurry (13 kg ha-1) following spring cereals (0.16 kg ha-1) and than in the unfertilised control (0.07 kg P ha-1). The proportion of DRP in TP in drainage water from the grass/clover crop rotation (35 %) was higher than from the spring cereal rotation (25 %) and the control (14 %). The grass/clover rotation proved to be very robust with respect to N leaching, with mean TN leaching of 10.5 kg ha-1 year-1 compared with 19.2 kg ha-1 year-1 from the cereal crop rotation. Pig slurry application after cereals in October resulted in TN leaching of 25.7 kg ha-1 compared with 7.0 kg ha-1 year-1 after application to grass/clover in October and 19.1 kg ha-1 year-1 after application to spring cereals in April. In conclusion, these results show that crop rotations dominated by forage leys need special attention with respect to DRP leaching and that slurry application should be avoided during wet conditions or combined with methods to increase adsorption of P to soil particles. © 2014 Springer Science+Business Media Dordrecht.

Spangberg J.,Swedish University of Agricultural Sciences | Tidaker P.,Swedish Institute of Agricultural and Environmental Engineering | Jonsson H.,Swedish University of Agricultural Sciences
Science of the Total Environment | Year: 2014

Human excreta are potential sources of plant nutrients, but are today usually considered a waste to be disposed of. The requirements on wastewater treatment plants (WWTPs) to remove nitrogen and phosphorus are increasing and to meet these requirements, more energy and chemicals are needed by WWTPs. Separating the nutrient-rich wastewater fractions at source and recycling them to agriculture as fertiliser is an alternative to removing them at the WWTP. This study used life cycle assessment methodology to compare the environmental impact of different scenarios for recycling the nutrients in the human excreta as fertiliser to arable land or removing them in an advanced WWTP. Three scenarios were assessed. In blackwater scenario, blackwater was source-separated and used as fertiliser. In urine scenario, the urine fraction was source-separated and used as fertiliser and the faecal water treated in an advanced WWTP. In NP scenario, chemical fertiliser was used as fertiliser and the toilet water treated in an advanced WWTP. The emissions from the WWTP were the same for all scenarios. This was fulfilled by the enhanced reduction in the WWTP fully removing the nutrients from the excreta that were not source-separated in the NP and urine scenarios. Recycling source-separated wastewater fractions as fertilisers in agriculture proved efficient for conserving energy and decreasing global warming potential (GWP). However, the blackwater and urine scenarios had a higher impact on potential eutrophication and potential acidification than the WWTP-chemical fertiliser scenario, due to large impacts by the ammonia emitted from storage and after spreading of the fertilisers. The cadmium input to the arable soil was very small with urine fertiliser. Source separation and recycling of excreta fractions as fertiliser thus has potential for saving energy and decreasing GWP emissions associated with wastewater management. However, for improved sustainability, the emissions from storage and after spreading of these fertilisers must decrease. © 2014.

Arvidsson J.,Swedish University of Agricultural Sciences | Westlin H.,Swedish Institute of Agricultural and Environmental Engineering | Keller T.,Swedish University of Agricultural Sciences | Keller T.,Agroscope Research Station ART | Gilbertsson M.,Swedish Institute of Agricultural and Environmental Engineering
Soil and Tillage Research | Year: 2011

Traditionally, tractors have been built either for tracks or wheels, with tracks mainly on heavy tractors with high power. Today, it is possible to retrofit four separate track units on a conventional agricultural tractor, creating interesting possibilities for agriculture. The objective of the present study was to compare soil compaction and traction for tracks, single and dual wheels mounted on the same tractor type. Measurements were made on two clay soils (Eutric Cambisols) in Sweden in 2009, using an 85kW tractor with a total weight of 7700kg. The rubber track system consisted of four tracks mounted on the conventional wheel axles of the tractor. The measured stresses were similar for the tracks and dual wheels at all depths studied (15, 30 and 50cm), but were considerably higher for the single wheels at all depths. Simulations of soil stresses correlated closely to measured values for the tracks and the dual wheels, but underestimated soil stresses in the topsoil compared to measured values for the single wheel. Bulk density and penetration resistance were consistently highest and saturated hydraulic conductivity lowest after wheeling with single wheels, while there were no statistically significant differences between tracks and dual wheels. With single wheels and the tractor loaded, saturated hydraulic conductivity decreased to 0.01mh-1 from 0.13mh-1 in the control, while bulk density increased from 1.24 to 1.36Mgm-3. The stress distribution in the driving direction was relatively even along the front and rear tracks, which is an advantage compared with a long single track, which often has an uneven longitudinal stress distribution. Slip was significantly higher for the dual and single wheels compared with tracks. To utilise the large contact area of the tracks, the tractor should have a low weight in relation to the engine power. © 2011 Elsevier B.V.

Westerholm M.,Swedish University of Agricultural Sciences | Hansson M.,Swedish Institute of Agricultural and Environmental Engineering | Schnurer A.,Swedish University of Agricultural Sciences
Bioresource Technology | Year: 2012

Whole stillage, as sole substrate or co-digested with cattle manure, was evaluated as substrate for biogas production in five mesophilic laboratory-scale biogas reactors, operating semi-continuously for 640days. The process performance was monitored by chemical parameters and by quantitative analysis of the methanogenic and acetogenic population. With whole stillage as sole substrate the process showed clear signs of instability after 120days of operation. However, co-digestion with manure clearly improved biogas productivity and process stability and indicated increased methane yield compared with theoretical values. The methane yield at an organic loading rate (OLR) at 2.8gVS/(L×day) and a hydraulic retention time (HRT) of 45days with a substrate mixture 85% whole stillage and 15% manure (based on volatile solids [VS]) was 0.31N L CH 4/gVS. Surprisingly, the abundance of the methanogenic and acetogenic populations remained relatively stable throughout the whole operation and was not influenced by process performance. © 2012 Elsevier Ltd.

de Toro A.,Swedish University of Agricultural Sciences | Gunnarsson C.,Swedish Institute of Agricultural and Environmental Engineering | Lundin G.,Swedish Institute of Agricultural and Environmental Engineering | Jonsson N.,Swedish Institute of Agricultural and Environmental Engineering
Biosystems Engineering | Year: 2012

This study simulated 30 years of harvesting operations on an hourly basis with a harvesting model linked to a grain moisture model capable of predicting the moisture content of standing ripe wheat using historical weather data from Stockholm, Sweden, as input, in order to assess the effects of weather on cereal harvesting costs. Several combinations of harvester size and grain moisture ceiling were assessed on three cereal areas in terms of overall costs (machine + labour + timeliness + drying) and their annual variations.The main findings obtained by simulation and valid for regions with similar climate and agricultural conditions to the studied region were that: (a) available combining time was highly dependent on grain moisture ceiling, which showed large annual variation, e.g. a moisture ceiling of 21% (w.b.) was related to a potential harvesting time of 65% and a standard deviation of 24% (n = 30 years); (b) in order to complete harvesting operations in most years, it was necessary to operate at a moisture ceiling of 22-24% (w.b.), however, the average moisture content of the harvested grain was much lower, about 17-18%; (c) overall harvesting costs were estimated at approx €140 ha -1 for those systems performing relatively well, i.e. with a daily harvesting capacity of 4-5% of the cereal area and operating at a moisture ceiling of 22-24% (w.b.); and (d) the main sources of annual cost variation were firstly the timeliness costs and secondly the drying costs. © 2012 IAgrE.

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