Agricultural waste as household fuel: Techno-economic assessment of a new rice-husk cookstove for developing countries

In many rural contexts of the developing world, agricultural residues and the organic fraction of waste are often burned in open-air to clear the lands or just to dispose them. This is a common practice which generates uncontrolled emissions, while wasting a potential energy resource. This is the case of rice husk in the Logone Valley (Chad/Cameroon). In such a context household energy supply is a further critical issue. Modern liquid fuel use is limited and traditional solid fuels (mainly wood) are used for daily cooking in rudimentary devices like 3-stone fires, resulting in low efficiency fuel use, huge health impacts, increasing exploitation stress for the local natural resources. Rice husk may be an alternative fuel to wood for household energy supply. In order to recover such a biomass, the authors are testing a proper stove with an original design. Its lay-out (featuring a metal-net basket to contain the fuel and a chimney to force a natural air draft) allows a mix of combustion/gasification of the biomass occurring in a completely burning fire, appropriate for cooking tasks. According to results obtained with rigorous test protocols (Water Boiling Test), different lay-outs have been designed to improve the performance of the stove. Technical and economic issues have been addressed in the development of such a model; building materials have been chosen in order to guarantee a cost as low as possible, using locally available items. The feasibility of the introduction of the stove in the studied context was assessed through an economic model that keeps into account not only the technology and fuel costs, but also the energy performance. According to the model, the threshold for the trade-off of the stove is the use of rice husk to cover 10–15% of the household energy needs both with traditional fireplaces or with improved efficiency cookstoves. The use of the technology proposed in combination with improved woodstove would provide householders with an appropriate and convenient cooking technology portfolio, increasing the opportunities of choice of the preferred energy system for the user and allowing significant savings for the family budget (up to 50% of the total annual cooking energy expenditure). The proposed model may be used also as a tool for the evaluation of the affordability or for the comparison of different cooking technologies also in other similar contexts, given their specific techno-economic parameter values.     

Application of a Random Forest algorithm to predict spatial distribution of the potential yield of Ruditapes philippinarum in the Venice lagoon, Italy

We present a modelling framework that combines machine learning techniques and Geographic Information Systems to support the management of an important aquaculture species, Manila clam (Ruditapes philippinarum). We use the Venice lagoon (Italy), the first site in Europe for the production of R. philippinarum, to illustrate the potential of this modelling approach. To investigate the relationship between the yield of R. philippinarum and a set of environmental factors, we used a Random Forest (RF) algorithm. The RF model was tuned with a large data set (n = 1698) and validated by an independent data set (n = 841). Overall, the model provided good predictions of site-specific yields and the analysis of marginal effect of predictors showed substantial agreement among the modelled responses and available ecological knowledge for R. philippinarum. The most influent environmental factors for yield estimation were percentage of sand in the sediment, salinity, and water depth. Our results agree with findings from other North Adriatic lagoons. The application of the fitted RF model to continuous maps of all the environmental variables allowed estimates of the potential yield for the whole basin. Such a spatial representation enabled site-specific estimates of yield in different farming areas within the lagoon. We present a possible management application of our model by estimating the potential yield under the current farming distribution and comparing it to a proposed re-organization of the farming areas. Our analysis suggests a reduction of total yield is likely to result from the proposed re-organization.     

A qualitative descriptive case study on home medical waste management in Brazil

Journal of Material Cycles and Waste Management - This work presents a survey on the management of the home medical care waste (HMCW) from the municipality of Caruaru, an important medical and...     

Environmental assessment of gas management options at the Old Ämmässuo landfill (Finland) by means of LCA-modeling (EASEWASTE)

The current landfill gas (LFG) management (based on flaring and utilization for heat generation of the collected gas) and three potential future gas management options (LFG flaring, heat generation and combined heat and power generation) for the Old Ämmässuo landfill (Espoo, Finland) were evaluated by life-cycle assessment modeling. The evaluation accounts for all resource utilization and emissions to the environment related to the gas generation and management for a life-cycle time horizon of 100 yr. The assessment criteria comprise standard impact categories (global warming, photo-chemical ozone formation, stratospheric ozone depletion, acidification and nutrient enrichment) and toxicity-related impact categories (human toxicity via soil, via water and via air, eco-toxicity in soil and in water chronic).The results of the life-cycle impact assessment show that disperse emissions of LFG from the landfill surface determine the highest potential impacts in terms of global warming, stratospheric ozone depletion, and human toxicity via soil. Conversely, the impact potentials estimated for other categories are numerically-negative when the collected LFG is utilized for energy generation, demonstrating that net environmental savings can be obtained. Such savings are proportional to the amount of gas utilized for energy generation and the gas energy recovery efficiency achieved, which thus have to be regarded as key parameters. As a result, the overall best performance is found for the heat generation option – as it has the highest LFG utilization/energy recovery rates – whereas the worst performance is estimated for the LFG flaring option, as no LFG is here utilized for energy generation.Therefore, to reduce the environmental burdens caused by the current gas management strategy, more LFG should be used for energy generation. This inherently requires a superior LFG capture rate that, in addition, would reduce fugitive emissions of LFG from the landfill surface, bringing further environmental benefits.     

Untersuchungen zur Eignung wildlebender Wanderratten (Rattus norvegicus) als Indikatoren der Schwermetallbelastung

Depot compartments which are the primary sites of pollutant enrichment in the organism can be used as bioindicators (targets) in order to identify a burden for certain elements. Background concentrations of eleven elements in tissues and organs of wild-living rats (Rattus norvegicus) obtained from a region (Euroregion Neisse, around the trilateral border region of Germany, Poland and the Czech Republic) distinguished by low to intermediate levels of environmental contaminations are given in part I of this work. In order to identify the most important depot compartments for certain elements, a body burden method was applied. Differences of affinity due to sex and age of analyzed rats are discussed, as are the suitability of specific organs and tissues with regard to bioaccumulation measurements concerning metals. The principal depot compartments for the heavy metals Cu, Mn, Cd (in adult rats) and Tl are the liver and kidneys, whereas the elements Ni, Sr, Pb (for adult animals) and Ti are more affinitivly to bones. Co and Zn displayed a more pronounced affinity towards tissues of the bones and liver. The analysis revealed large differences in Cd and Pb distributions both among young and adult rats, and with respect to sexes. It can be concluded that the distribution of the elements investigated in this study in free-living rats agrees with that in man, except for that of Ni. The above agreement gives proof of the possibility to use depot organs of rats for bioindication which was already mentioned in part I of this work (‘Sex and age-related quantification of Al, As, Cd, Co, Cu, Mn, Ni, Pb, Sr, Ti, Tl and Zn in liver, heart, lung, kidney, muscle, brain and bones and establishment of distribution patterns’).     

Autotrophic nitrogen removal for decentralized treatment of ammonia-rich industrial textile wastewater: process assessment,stabilization and modelling

Environmental Science and Pollution Research - Digital textile printing (DTP) is a game-changer technology that is rapidly expanding worldwide. On the other hand, process wastewater is rich in...     

Inventory and conservation assessment for the management of coastal dunes,Veneto coasts,Italy

Management of coastal dunes on developed coasts could effectively take advantage of comprehensive and multitemporal georeferenced data collection, which offers the possibility to relate dune data with the natural and cultural characteristics of the beach and hinterland. The recent implementation of a coastal management geodatabase for the Veneto region provides the opportunity for improving knowledge on coastal dunes on developed littoral as well as a basis for appropriate future coastal planning in the study area. The geodatabase gathers data concerning different physical, evolutionary and human aspects of the coastal zone, with a special focus on coastal dunes. Established foredunes, human-altered dunes and relict dunes are irregularly distributed along 59 km, 38% of the entire coastal length. Their distribution and characteristics are the result of favourable natural conditions as well as long-lasting tourism exploitation (evaluated through an index of Land Use Pressure) and fragmentary and diversified uses of beaches (evaluated through an index of Tourism Pressure on the beach). At the same time, beach/dune nourishment intervention allowed the presence of artificial or sand fenced dunes along 17 km of coast. High dune elevation up to 8–10 m is promoted by the onshore exposition of the beach to dominant wind (from ENE), by stable-to-slowly negative sedimentary budget or by the re-activation of high relict foredunes in the case of shoreline retreat associated with strong negative budget. Present sedimentary budget (evaluated through the code ASPE – Accretion, Stable, Precarious, Erosive) is the tool used for dividing coasts in sedimentary compartments or cells. Past and present sedimentary budget and different human responses to erosive cases (hard and soft interventions) give the foredunes different means to form, grow, survive and evolve over time. The assessment of Human Impact and Active Management Practices on the dunes allows a first evaluation of the Management Effectiveness, which shows strong shortcomings for 81% of the dunes. The great variability of beach usage, human impact and management practises on the different dune stretches highlight the lack of effective and systematic management actions being correctly scheduled and performed.     

Untersuchungen zur Eignung wildlebender Wanderratten (Rattus norvegicus) als Indikatoren der Schwermetallbelastung

Zusammenfassung  Durch die Quantifizierung von 12 chemischen Elementen im Organsystem von wildlebenden Ratten (Rattus norvegicus) aus dem Tierpark Zittau (Sachsen) sollte die Eignung dieser spezies als passiver Bioindikator untersucht werden. Neben der Ermittlung von sogenannten Hintergrund-konzentrationen standen insbesondere Fragen zur geschlechts-und altersspezifischen Akkumulation einzelner Elemente im Organsystem von Rattus norvegicus im Vordergrund. Spezifisch zeigten dabei einzelne Elemente unterschiedliche Affinit?ten zu den entsprechenden Geweben und Organen. Insbesondere die hierbei ermittelten geschlechts- und altersspezifischen Charakteristika einzelner Elemente macht eine detaillierte Ausarbeitung einer Beprobungsstrategie für den sp?teren Einsatz als passiver Bioindikator zwingend. Unter Berücksichtigung des durch die Berechnung des Body Burden (K?rperlast) im 2. Teil der Arbeit ermittelten typischen Verteilungsmusters einzelner Elemente ist Rattus norvegicus zum integrativen Monitoring-einsatz pr?destiniert. Bernd Markert ist Professor und Direktor des internationalen Hochschulinstitutes in Zittau und Lehrstuhlinhaber für Umweltverfahrenstechnik. Der Einsatz eines freilebenden, intelligenten ‘Sch?dlings’ für die Umweltüberwachung in der Bioindikation ergibt sich für ihn aus zwei zwingenden Gesichtspunkten: 1. Die Ratte als Nutztier (psychologisch/didaktischer Ansatz) 2. und als ‘missing link’ zwischen Wirbeltier und Mensch (bioindikativer/naturwissenschaftlicher Ansatz)