Search results for "fertilizers"
showing 10 items of 39 documents
Application of a fuzzy algorithm for pH control in a struvite crystallisation reactor
2006
A struvite crystallisation process is highly dependent on pH. To achieve a high phosphorus recovery as struvite it is important to have an accurate control of pH in the reactor. The high non-linear response of pH value makes manual pH control difficult. Therefore, a software based on fuzzy logic control (FLC) has been developed to maintain the pH at a set value in a stirred reactor to crystallise struvite. The FLC developed has been based on Larsen's inference. In order to confirm the improvement of the pH stability using FLC software, different experiments have been carried out with manual control of the pH value, and with the FLC software. It has been demonstrated that using FLC software …
Embedding “substrate” in environmental assessment of green roofs life cycle: evidences from an application to the whole chain in a Mediterranean site
2012
Abstract A classical LCA methodology is here applied to green roofs including in this analysis also the whole life cycle of the substrate, that represented a lack of previous LCA studies on green roofs. This inclusion will allow a complete and proper application of the LCA methodology to achieve an environmental accounting of the “green roof” performance. We have here chosen to approach the problem by analysing a specific substrate, that is used within an actual extensive green roof. Afterwards, we have applied the LCA methodology to the whole actual extensive green roof whose substrate under analysis is part of. In this manner, we achieved an environmental accounting of the “green roof” pe…
Life cycle assessment of olive oil: A case study in southern Italy
2018
Abstract The paper describes the results of a specific LCA based analysis of the production of olive oil in the region of Calabria, in southern Italy. The goal of the study is to assess the energy and environmental impacts of different scenarios involving conventional and organic cultivations, plains and hills cultivations and involving different operating techniques. The study also aims at assessing the share of each life cycle step on the total of energy and environmental impacts. The functional unit chosen for the comparative analysis is a glass bottle of 0.75 L of extra virgin olive oil. A “from cradle to gate” perspective was chosen. The analysis was developed according to the LCA stan…
Anaerobically digested poultry slaughterhouse wastes as fertiliser in agriculture
2001
Chemical and physical analysis, 27-d plant growth assays with carrot (Daucus carota) and Chinese cabbage (Brassica campestris var. chinensis), and 5-d phytotoxicity assays with Chinese cabbage and perennial ryegrass (Lolium perenne) were used to investigate the suitability of anaerobically digested poultry slaughterhouse waste for fertiliser in agriculture and the effect of aerobic post-treatment on the properties of the digested material. The digested material appeared to be rich in nitrogen. In 27-d assays with digested material as nitrogen source, carrots grew almost as well as those fertilised with a commercial mineral fertiliser used as reference, whereas, the growth of Chinese cabbage…
Are agricultural soils under a continental temperate climate susceptible to episodic reducing conditions and increased leaching of phosphorus?
2012
International audience; Soil science research has probably underestimated the significance that short-term, episodic cycles of reduction and oxidation has had on phosphorus (P) reactivity. Here, the effects of eleven pulsed reduction-oxidation (including wet-dry) cycles on soil P dynamics are compared for 12 soils having contrasting properties and all overfertilised with respect to P. The laboratory based incubation conditions attempted to simulate transient waterlogging of the soil profile and involved repeated sampling and analysis of both the solution and solid phase P forms. An initial increase in P concentration in solution that occurred up to and including the fourth full cycle was fo…
Release of phosphorus under reducing and simulated open drainage conditions from overfertilised soils
2014
Does removal of cations from soil solution during soil reduction stimulate phosphorus (P) release? An ion-exchange resin system was employed to provide a sink during the incubation of twelve soils under fully reducing conditions. This experimental design was considered to better simulate the loss of ions likely to occur under field conditions than more routine batch type closed extraction systems where solutes build-up in the extract solution. The small solute concentrations that remain in the equilibrating solution suggest the mixed resin system acted as an effective sink over the whole experimental period. By maintaining a small P concentration the resin system mimics soil drainage condit…
Screening of novel plants for biogas production in northern conditions.
2013
Abstract The objective of this study was to screen nine annual or perennial novel plants for biogas production cultivated in years 2007–2010 in Finland. The most promising novel plants for biogas production were found to be brown knapweed, giant goldenrod and Japanese millet producing 14–27 t total solids/ha and 4000–6100 Nm 3 CH 4 /ha. The specific methane yields of all studied plants varied from 170 to 381 Nm 3 CH 4 /t volatile solids (VS), depending on harvest time and plant species. Co-digestion of brown knapweed with cow manure in continuously stirred tank reactor was investigated and the highest methane yield was 254 NL CH 4 /kg VS, when the share of brown knapweed was 50% in the fe…
An integral approach to sludge handling in a WWTP operated for EBPR aiming phosphorus recovery: simulation of alternatives, LCA and LCC analyses
2020
[EN] As phosphorus is a non-renewable resource mainly used to produce fertilizers and helps to provide food all over the world, the proper management of its reserves is a global concern since it is expected to become scarcer in the near future. In this work we assessed two different sludge line configurations aiming for P extraction and recovery before anaerobic digestion and compared them with the classical configuration. This study has been performed by simulation with the model BNRM2 integrated in the software package DESASS 7.1. Configuration 1 was based on the production of a PO4-enriched stream from sludge via elutriation in the primary thickeners, while Configuration 2 was based on t…
Effetti delle epoche e modalità di concimazione su produzione e qualità del finocchio. Effects of time and method of fertilizer application on yield …
2010
Two field trials were carried out in Sicily during fall-winter and spring season to determine the influence of 9 fertilization treatments, obtained by changing the time (pre-plant and/or post-plant fertilization), and method (broadcast fertilization and/or fertigation) of fertilizer application and the type of fertilizer (mineral, organic, slow release fertilizers) on yield and quality of fennel. An unfertilized treatment (control) was also included. In all fertilized treatments, macronutrients were applied at the following total rates (kg ha-1): N (350), P2O5 (100), K2O (208). In both trials the highest yield and mean bulb weight was obtained by pre-planting application of all mineral fert…
Quantifying the contribution of nitrification and denitrification to the nitrous oxide flux using 15N tracers.
2006
8 pages; International audience; Microbial transformations of nitrification and denitrification are the main sources of nitrous oxide (N2O) from soils. Relative contributions of both processes to N2O emissions were estimated on an agricultural soil using 15N isotope tracers (15NH4+ or 15NO3-), for a 10-day batch experiment. Under unsaturated and saturated conditions, both processes were significantly involved in N2O production. Under unsaturated conditions, 60% of N-N2O came from nitrification, while denitrification contributed around 85-90% under saturated conditions. Estimated nitrification rates were not significantly different whatever the soil moisture content, whereas the proportion o…