An Approach to the Simulation of a Batch-respirometer

Dynamic models in activated sludge processes have demonstrated to be a reliable and useful instrument in design and management of wastewater treatment plants. The biochemical nature of the processes involved the models which need a specific calibration to local conditions. A common method to determine kinetic and stoichiometric parameters of the biomass or wastewater/sludge fractionations is respirometry. Theoretically, nearly all biomass parameters and fractions can be estimated by respirometry, but a lot of difficulties rise when some parameters, such as saturation and hydrolysis rate constants, have to be drawn from experimental data. The aim of our work is the setting up of a simple method to calibrate Activated Sludge Model No. 1 applying traditional batch respirometric tests together with dynamic simulations of the respirometer itself

Characterization and BMP Tests of Liquid Substrates for High-rate Anaerobic Digestion

This work was focused on the physicochemical characterization and biochemical methane potential (BMP) tests of some liquid organic substrates, to verify if they were suitable for undergoing a process of high-velocity anaerobic digestion. The selected substrates were: first and second cheese whey, organic fraction of municipal solid waste (OFMSW) leachate, condensate water and slaughterhouse liquid waste. Firstly, a physicochemical characterization was performed, using traditional and macromolecular parameters; then, batch anaerobic tests were carried out, and some continuous tests were planned. The results revealed that all the analyzed substrates have a potential to be anaerobically treated. Valuable information about treatment rate for a high-velocity anaerobic digestion process was obtained. Start-up of a lab-scale UASB reactor, treating diluted cheese whey, was successfully achieved with good COD removal efficiency. These preliminary results are expected to be further investigated in a successive phase, where continuous tests will be conducted on condensate water and OFMSW leachate. This work is licensed under a Creative Commons Attribution 4.0 International License

Automated calibration of the EPA-SWMM model for a small suburban catchment using PEST: a case study

Rainfall-runoff models must be calibrated and validated before they can be used for urban stormwater management. Manual calibration is very difficult and time-consuming due to the large number of model parameters that must be estimated concurrently. Automatic calibration offers as a promising alternative, ideally supporting a user-independent and time-efficient approach to model parameters estimation. In this article, we test the use of a state-of-the-art standard package (PEST, Parameter ESTimation, http://www.pesthomepage.org/) for the automatic calibration of a rainfall-runoff EPA-SWMM (Storm Water Management Model) model developed for a small suburban catchment. Results reported in the paper demonstrate that the performance of automatically calibrated models still depends on a number of user-dependent choices (the level of catchment discretization, the selection of significant parameters, the optimization techniques adopted). Through a systematic analysis of the results, we try to identify the guidelines for the effective use of automatic calibration procedures based on modeling assumptions and target of the analysis

Greenhouse gas emissions from agricultural food production to supply Indian diets: Implications for climate change mitigation

Agriculture is a major source of greenhouse gas (GHG) emissions globally. The growing global population is putting pressure on agricultural production systems that aim to secure food production while minimising GHG emissions. In this study, the GHG emissions associated with the production of major food commodities in India are calculated using the Cool Farm Tool. GHG emissions, based on farm management for major crops (including cereals like wheat and rice, pulses, potatoes, fruits and vegetables) and livestock-based products (milk, eggs, chicken and mutton meat), are quantified and compared. Livestock and rice production were found to be the main sources of GHG emissions in Indian agriculture with a country average of 5.65 kg CO2eq kg-1 rice, 45.54 kg CO2eq kg-1 mutton meat and 2.4 kg CO2eq kg-1 milk. Production of cereals (except rice), fruits and vegetables in India emits comparatively less GHGs with <1 kg CO2eq kg-1 product. These findings suggest that a shift towards dietary patterns with greater consumption of animal source foods could greatly increase GHG emissions from Indian agriculture. A range of mitigation options are available that could reduce emissions from current levels and may be compatible with increased future food production and consumption demands in India

Heavy metals in the irrigation water, soils and vegetables in the Philippi horticultural area in the Western Cape Province of South Africa

The aims of this study were to investigate the extent of heavy metal contamination in the Philippi horticultural area in the Western Cape Province, South Africa. Concentrations of Cd, Cr, Cu, Mn, Ni, Pb and Zn were determined in the irrigation water, soils and vegetables in both winter and summer cropping seasons with an ICP-AES and tested against certified standards. Differences were found in heavy metal concentrations between the winter and summer cropping seasons in the irrigation water, soils and vegetables. Certain heavy metals exceeded the maximum permissible concentrations in the irrigation water, soils and vegetables produced in South Africa. These toxic concentrations were predominantly found in the summer cropping season for the soils and in the crops produced in winter. It is thus suggested that further studies are carried out in the Philippi horticultural area to determine the sources of the heavy metals to try and mitigate the inputs thereof and therefore reduce the amount of heavy metals entering the human food chain.ISI & Scopu

Treatment of Landfill Leachate by H2O2 Promoted Wet Air Oxidation: COD-AOX Reduction, Biodegradability Enhancement and Comparison with a Fenton-type Oxidation

Treatment experiments of a landfill leachate were performed by wet air oxidation (WAO) with the addition of H2O2 (as free radical promoter), and a Fenton-type (at pH ≈ 7) process, in order to compare COD (chemical oxygen demand) and AOX (adsorbable organic halogen) reduction as well as biodegradability enhancement measured by OUR respirometric parameter. The WAO reactions were performed in a batch reactor at various temperatures in the range of T = 430-500 K employing a concentration of c = 0.88 mol L–1 of H2O2. The same H2O2 concentration was used in the Fenton-type-pH ≈ 7 experimental session considering H2O2/Fe(II) mole ratios of 5, 10 and 15. Similar results were obtained in COD abatement but appreciably different performance in AOX removal and biodegradability enhancement was observed. A comparison between the treatment trials brought to the evidence that Fenton-Type-pH ≈ 7 process has poor performance in biodegradability enhancement, diversely the H2O2 promoted WAO get to better performances even at mild temperature. This process could be considered as advantageous solution in landfill leachate pre-treatment when the main objectives are COD and AOX degradation together with the biodegradability enhancement for final treatment in common biological aerobic wastewater treatment plants

Psychobiological evidence of the stress resilience fostering properties of a cosmetic routine

Everyday life psychosocial stressors contribute to poor health and disease vulnerabilty. Means alternative to pharmacotherapy that are able to foster stress resilience are more and more under the magnifying glass of biomedical research. The aim of this study was to test stress resilience fostering properties of the self-administration of a cosmetic product enriched with essential oils. On day 0, fourty women, 25-50 years old, self-administered both the enriched cosmetic product (ECP) and a placebo one (PCP). Then, women were randomized for daily self-administration (from day 1 to 28) of either ECP (n = 20) or PCP (n = 20). On day 29, subjects underwent a psychosocial stress test (PST). Autonomic (heart rate and its variability) and neuroendocrine (salivary cortisol) parameters were assessed both on day 0 and 29. All subjects filled a number of psychological questionnaires in order to quantify anxiety, perceived stress, and mood profile, and were videorecorded during PST for non-verbal behavior evaluation. A single application of ECP produced an acute potentiation of cardiac parasympathetic modulation, which was not observed when placebo was used. Prolonged self-administration of ECP induced: (i) a dampening of the cortisol rise produced by PST, (ii) a reduction of state anxiety, (iii) a favorable change in mood profile, and (iv) a reduction of non-verbal behavior patterns that signal anxiety, motivational conflict and avoidance. In conclusion, this study suggests that the self-administration of a cosmetic cream enriched with essential oils should be considered as a stress resilience fostering strategy due to its favorable physiological, neuroendocrine and psychological effects