Search results for "GAS"
showing 10 items of 12601 documents
Phytotoxic Effects of Commercial Eucalyptus citriodora, Lavandula angustifolia, and Pinus sylvestris Essential Oils on Weeds, Crops, and Invasive Spe…
2019
Background: essential oils are well known for their pharmacological effectiveness as well as their repellent, insecticide, and herbicide activities. The emergence of resistant weeds, due to the overuse of synthetic herbicides, makes it necessary to find natural alternatives for weed control. The aim of this study was to evaluate the phytotoxic effects of Eucalyptus citriodora, Lavandula angustifolia, and Pinus sylvestris, three common commercial essential oils, on weeds (Portulaca oleracea, Lolium multiflorum, and Echinochloa crus-galli), food crops (tomato and cucumber), and the invasive species Nicotiana glauca. Methods: to determine herbicidal effects, essential oils were tested at diffe…
A new methodology for organic soils in national greenhouse gas inventories: Data synthesis, derivation and application
2020
Abstract Drained organic soils are large sources of anthropogenic greenhouse gases (GHG) in many European and Asian countries. Therefore, these soils urgently need to be considered and adequately accounted for when attempting to decrease emissions from the Agriculture and Land Use, Land Use Change and Forestry (LULUCF) sectors. Here, we describe the methodology, data and results of the German approach for measurement, reporting and verification (MRV) of anthropogenic GHG emissions from drained organic soils and outline ways forward towards tracking drainage and rewetting. The methodology was developed for and is currently applied in the German GHG inventory under the United Nations Framewor…
Collating science-based evidence to inform public opinion on the environmental effects of marine drilling platforms in the Mediterranean Sea.
2017
Abstract The use of rigorous methodologies to assess environmental, social and health impacts of specific interventions is crucial to disentangle the various components of environmental questions and to inform public opinion. The power of systematic maps relies on the capacity to summarise and organise the areas or relationships most studied, and to highlight key gaps in the evidence base. The recent Italian technical referendum (2016) – a public consultation inviting people to express their opinion by voting to change the rules on the length of licence duration and the decommissioning of offshore oil and gas platform drilling licences – inspired the creation of a systematic map of evidence…
Parameter identification and state estimation of a microalgae dynamical model in sulphur deprived conditions: Global sensitivity analysis, optimizati…
2014
International audience; In this article, a dynamic model describing the growth of the green microalgae Chlamydomonas reinhardtii , under light attenuation and sulphur‐deprived conditions leading to hydrogen production in a photobioreactor is presented. The strong interactions between biological and physical phenomena require complex mathematical expressions with an important number of parameters. This article presents a global identification procedure in three steps using data from batch experiments. First, it includes the application of a sensitivity function analysis, which allows one to determine the parameters having the greatest influence on model outputs. Secondly, the most influentia…
Aeration control in membrane bioreactor for sustainable environmental footprint
2020
In this study different scenarios were scrutinized to minimize the energy consumption of a membrane bioreactor system for wastewater treatment. Open-loop and closed-loop scenarios were investigated by two-step cascade control strategies based on dissolved oxygen, ammonia and nitrite concentrations. An integrated MBR model which includes also the greenhouse gas formation/emission processes was applied. A substantial energy consumption reduction was obtained for the closed-loop scenarios (32% for Scenario 1 and 82% for Scenario 2). The air flow control based on both ammonia and nitrite concentrations within the aerobic reactor (Scenario 2) provided excellent results in terms of reduction of o…
Anaerobic membrane bioreactor (AnMBR) scale-up from laboratory to pilot-scale for microalgae and primary sludge co-digestion: Biological and filtrati…
2020
This research work proposes the scale-up evaluation in terms of biological and filtration performance from laboratory to pilot-scale of an anaerobic membrane bioreactor (AnMBR) co-digesting raw microalgae and primary sludge. Best operating conditions for this scale-up were energetically and economically assessed based on laboratory results. Economic balance showed 3% higher annual costs when operating a reactor at 100 d solids retention time (SRT) compared to 70 d SRT. Energetic balance showed a 5.5-fold increase in heat demand working at thermophilic temperature comparing to mesophilic. The AnMBR operating conditions were set at 70 d SRT and 35 °C. The pilot-scale and lab-scale co-digester…
Enhanced high-quality biomethane production from anaerobic digestion of primary sludge by corn stover biochar
2020
Abstract This study conducted batch and continuous tests to reveal the feasibility of corn stover biochar on improving anaerobic digestion of primary sludge (PS). Dosing biochar (1.82, 2.55 and 3.06 g/g Total Solids (TS)) in digester improved methane content increasing from 67.5% to 81.3–87.3% and enhanced methane production by 8.6–17.8%. Model analysis indicated that biochar accelerated PS hydrolysis and enhanced methane potential of PS. The mechanistic studies showed that biochar enhanced process stability provided by strong buffering capacity and alleviated NH3 inhibition. In continuous test over 116 days, the volatile solids (VS) destruction in the biochar-dosed digester increased by 14…
A plant-wide modelling comparison between membrane bioreactors and conventional activated sludge
2020
Abstract A comprehensive plant-wide mathematical modelling comparison between conventional activated sludge (CAS) and Membrane bioreactor (MBR) systems is presented. The main aim of this study is to highlight the key features of CAS and MBR in order to provide a guide for an effective plant operation. A scenario analysis was performed to investigate the influence on direct and indirect greenhouse gas (GHG) emissions and operating costs of (i) the composition of inflow wastewater (scenario 1), (ii) operating conditions (scenario 2) and (iii) oxygen transfer efficiency (scenario 3). Scenarios show higher indirect GHG emissions for MBR than CAS, which result is related to the higher energy con…
Microbial communities involved in biogas production exhibit high resilience to heat shocks
2017
We report here the impact of heat-shock treatments (55 and 70 °C) on the biogas production within the acidification stage of a two-stage reactor system for anaerobic digestion and biomethanation of grass. The microbiome proved both taxonomically and functionally very robust, since heat shocks caused minor community shifts compared to the controls, and biogas yield was not decreased. The strongest impact on the microbial profile was observed with a combination of heat shock and low pH. Since no transient reduction of microbial diversity occured after the shock, biogas keyplayers, but also potential pathogens, survived the treatment. All along the experiment, the heat-resistant bacterial prof…
Filling gaps: closing the life cycle of the endangered Mediterranean limpet Patella ferruginea Gmelin, 1791 (Gastropoda, Patellidae)
2020
Several reproductive issues and the larval development of the ferruginous limpet, Patella ferruginea Gmelin, 1791, an endangered species endemic from the western Mediterranean Sea, were studied to fill gaps in the knowledge of its life cycle. Average diameter of mature oocytes was 141.83 μm and mean oocyte density in the ovary was 283,800 oocytes/gram. No significant correlations were found between both oocyte diameter or density and female shell length. Female fecundity (number of oocytes per gonad) was significantly correlated with shell length and varied between 189,200 oocytes in a 40.0 mm female and 5,019,200 oocytes in an 86.4 mm female. However, there was considerable variability, in…