Suchergebnisse

23 Páginas.-- 6 Tablas.-- 5 Figuras ; The table olive industry produces a high quantity of wastewater annually. These wastewaters are very problematic because of their characteristics of high organic matter, high phenolic content, high salinity and conductivity. The quantities in which they are produced are also a serious problem. The worldwide production of table olives reached 2,550,000 tons in the last five campaigns, with the European Union contributing to 32% of total production. The problem of these wastewaters is focused on the Mediterranean area where the highest quantity of table olives is produced and to a lesser extent on the United States and South America. Countries like Spain produce around 540,000 tons of these wastewaters. At present, there is no standard treatment for these wastewaters with acceptable results and which is applied in the industry. Currently, the most common treatment is the storage of these wastewaters in large evaporation ponds where, during the dry season, the wastewater disappears due to evaporation. This is not a solution as the evaporation ponds depend completely on the climatology and have a high number of associated problems, such as bad odors, insect proliferation and the contamination of underground aquifers. Different studies have been carried out on table olive wastewater treatment, but the reality is that at the industrial level, none has been successfully applied. New and promising treatments are needed. The current review analyzes the situation of table olive wastewater treatment and the promising technologies for the future. ; The authors wish to express their gratitude to the regional government of Andalucía, Junta de Andalucía, Consejería de Economía y Conocimiento (Project of Excellence RNM-1970) for providing financial support. Dr. Rincón wishes to thank the "Ramón y Cajal" Program (RYC-2011-08783 contract) from the Spanish Ministry of Economy and Competitiveness for providing financial support. They acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI). ; Peer reviewed

4 Tablas.-- 2 Figuras ; Spent livestock bedding is a valuable resource for the production of green energy (methane) in rural areas. Comparison and evaluation of batch anaerobic digestion and co-digestion of different mixtures of goat straw bedding (SGSB) and goat cheese whey were carried out. Biochemical methane potential (BMP) tests of the 100% SGSB, 95% SGSB-5% whey, 90% SGSB-10% whey, 85% SGSB-15% whey and 100% whey were found to be 423 ± 7, 354 ± 9, 371 ± 2, 293 ± 1, 274 ± 2 mL CH4 g−1 VS. Two different kinetic models were evaluated. The logistic model revealed a decrease in the maximum methane production rate (Rm) from 34.7 ± 1.5 to 14.1 ± 0.9 mL CH4 g−1 VS·d−1 when the percentage of whey in the mixture increased from 0 to 15% as a consequence of the increased ammonia released during the co-digestion of increased concentrations of whey. The lowest value for the maximum methane production predicted by the model (P) was found for 100% whey (274 ± 10 mL CH4 g−1 VS). A two-substrate model was applied to describe the evident existence of rapid and slowly degradable material. Regarding the hydrolysis kinetic constants predicted by this model, considerable increases in the rapid biodegradation stage (krapid) were observed when comparing to the values found for the slow (kslow) biodegradation stage in all the cases tested. The increases between both constants rose from 5 to 42% when the percentage of whey increased. ; The authors wish to thank to the regional government of Andalucía, Junta de Andalucía, Consejería de Economía y Conocimiento (Project of Excellence RNM-1970) for providing financial support. N.F. Puntano also wishes to thank the academic mobility and exchange program (PIMA). The PIMA program is a mobility initiative for undergraduate students promoted by the Ibero-American States Organization. The authors also wish especially to thank Manuel Vázquez (Sierra del Romero) for his contribution. ; Peer reviewed

30 Páginas; 2 Figuras; 4 Tablas ; This study investigated the effect of a steam-explosion pre-treatment on the anaerobic digestion of the two-phase olive mill solid waste (OMSW) or alperujo. The OMSW was subjected to a steam explosion pre-treatment at 200 °C and 1.57 MPa during 5 min. After this pre-treatment a solid fraction (SF) and a liquid fraction (LF) were generated. These two fractions were used to obtain methane through anaerobic digestion with the aim of evaluating the effect of the pre-treatment on the methane yields obtained. Biochemical methane potential (BMP) tests of both untreated OMSW and steam-explosion pre-treated OMSW, i.e. SF and LF, as described above, revealed that the maximum methane yield (589 ± 42 mL CH4/g VSadded) was achieved for the LF generated after the pre-treatment. From a kinetic point of view the BMP tests of untreated OMSW and the SF obtained after the pre-treatment showed a first exponential stage followed by a second sigmoidal stage after a lag period. By contrast for the LF, only a single exponential stage was observed. ; The authors wish to express their gratitude to the Spanish Ministry of Economy and Competitiveness (project CTM2014-55095-R) and the regional government of Andalucía "Junta de Andalucía" (project RNM-1970) for providing financial support. Dr. Rincón (RYC-2011-08783 contract) and Dr. Rodríguez-Gutiérrez (RYC-2012-10456 contract) wish to thank to the "Ramón y Cajal" Program from the Spanish Ministry of Economy and Competitiveness for its funding. ; Peer reviewed

16 Páginas.-- 7 Figuras.-- 2 Tablas ; This research was carried out with the aim to evaluate the anaerobic digestion (AD) of llama and dromedary dungs (both untreated and trampled) in batch mode at mesophilic temperature (35 °C). The biochemical methane potential (BMP) tests with an inoculum to substrate ratio of 2:1 (as volatile solids (VS)) were carried out. The methane yield from trampled llama dung (333.0 mL CH4 g−1 VSadded) was considerably higher than for raw llama, raw and trampled dromedary dungs (185.9, 228.4, 222.9 mL CH4 g−1 VSadded, respectively). Therefore, trampled llama dung was found to be the best substrate for methane production due to its high content of volatile solids as well as its high nitrogen content (2.1%) and more appropriate C/N ratio (23.6) for AD. The experimental data was found to be in accordance with both first-order kinetic and transference function mathematical models, when evaluating the experimental methane production against time. By applying the first-order kinetic model, the hydrolysis rate constants, kh, were found to be 19% and 11% higher for trampled dungs in comparison with the raw dung of dromedary and llama, respectively. In addition, the maximum methane production rate (Rm) derived from the transference function model for trampled llama dung (22.0 mL CH4 g−1 VS d−1) was 83.3%, 24.4% and 22.9% higher than those obtained for raw llama manure and for raw and trampled dromedary dungs, respectively. ; Funding for open access publishing: Universidad Pablo de Olavide/CBUA. This study was funded y the project FEDER UPO-1380782 financed by the regional government of Andalucía, Junta de Andalucía, Consejería de Trasformación Económica, Industria, Conocimiento y Universidades and the project PID2020-114975RB-100/AEI/10.13039/501100011033 financed by the Spanish Ministry of Science and Innovation. ; Peer reviewed

The table olive industry produces a high quantity of wastewater annually. These wastewaters are very problematic because of their characteristics of high organic matter, high phenolic content, high salinity and conductivity. The quantities in which they are produced are also a serious problem. The worldwide production of table olives reached 2,550,000 tons in the last five campaigns, with the European Union contributing to 32% of total production. The problem of these wastewaters is focused on the Mediterranean area where the highest quantity of table olives is produced and to a lesser extent on the United States and South America. Countries like Spain produce around 540,000 tons of these wastewaters. At present, there is no standard treatment for these wastewaters with acceptable results and which is applied in the industry. Currently, the most common treatment is the storage of these wastewaters in large evaporation ponds where, during the dry season, the wastewater disappears due to evaporation. This is not a solution as the evaporation ponds depend completely on the climatology and have a high number of associated problems, such as bad odors, insect proliferation and the contamination of underground aquifers. Different studies have been carried out on table olive wastewater treatment, but the reality is that at the industrial level, none has been successfully applied. New and promising treatments are needed. The current review analyzes the situation of table olive wastewater treatment and the promising technologies for the future.

This paper reviews the most relevant uses and applications of zeolites in anaerobic digestion processes. The feasibility of using natural zeolites as support media for the immobilization of microorganisms in different high-rate reactor configurations (fixed bed, fluidized bed, etc.) is also reviewed. Zeolite, with its favorable characteristics for microorganism adhesion, has also been widely used as an ion exchanger for the removal of ammonium in anaerobic digestion due to the presence of Na +, Ca 2+ and Mg 2+ cations in its crystalline structure. This property is also useful for improving the anaerobic process performances in the treatment of wastewaters with high concentrations of nitrogen compounds, such as cattle, pig and chicken wastes, as it prevents process inhibition. The influence of zeolite particle size and doses in batch mesophilic and thermophilic processes when referring to synthetic or different wastewaters is also reviewed. Finally, the role of zeolite in granulation processes, in anaerobic oxidation processes (Anammox) for promoting the retention of the biomass involved (given its low growth rate), and in hybrid and sequencing reactors such as the moving bed biofilm reactors (MBBR) are also discussed. © 2012 Elsevier B.V. ; The authors wish to express their gratitude to FONDECYT project no. 1090414 (Chile) and to DICYT091111MM project (Chile) as well as to the Ministry of Science and Technology (Spanish Government) (project CTM2008-05772/TECNO) for providing financial support. ; Peer Reviewed

The use of microalgae for biomethane production has been considerably increasing during the recent years. In this study, four dominant species belonging to the genera Scenedesmus, Chlorella, Dunaliella and Nostoc were selected. The influence of different genera with several morphological, structural and physicochemical characteristics on methane production was assessed in biochemical methane potential (BMP) tests. The ultimate methane yield values were 332 ± 24, 211 ± 2, 63 ± 17 and 28 ± 10 mL CH/g VS for Scenedesmus obliquus, Chlorella sorokiniana, Dunaliella salina and Nostoc sp., respectively. The highest methane production was achieved by microalga species that had no complex cell wall or wall basically composed by proteins and simple sugars such as in S. obliquus, whereas lower methane yields were found for D. salina and Nostoc sp., due to the salinity effects and cell wall composition in terms of complex polysaccharide and glycolipid layers, respectively. Kinetic constant values obtained in the BMP tests ranged between 1.00 ± 0.08 and 0.097 ± 0.005 days for D. salina and S. obliquus, respectively. ; The authors express their gratitude to Marie Curie's International Research Staff Exchange Scheme (PIRSES-GA-2011-295165) and Junta de Andalucía government (RNM-1970) for providing financial support. ; Peer Reviewed

The variation of the water quality of the Guadarrama river and its tributaries in a section of Las Rozas-Madrid, Spain, was studied during the time period between January 2003 and January 2008. The parameter water quality index (WQI) was used to determine the water quality based on the conventional parameters of pollution. It was found that the WQI was slightly affected in the section evaluated. The value of the WQI was in the range of 56-64, which corresponded to the classification of 'good quality'. It was determined that 64.3% of the organic matter present in the river was removed in the section of Las Rozas-Madrid. The river acted as a plug flow reactor and a first-order kinetics governed the ultimate biological oxygen demand (BOD5) (BODU) decay. The value of the first-order constant demonstrated the river's high self-purification capacity. In addition, a high linear relationship was found between the WQI and the dissolved oxygen deficit (D). Therefore, a quick determination of WQI may be carried out if the values of D are known. These are easily obtainable by field measurements. © 2009 CSIC, Consejo Superior de Investigaciones Científicas. Water and Environment Journal © 2009 CIWEM. ; We thank the municipal Government of 'Las Rozas-Madrid' (Madrid, Spain), the 'Consejeria de Medio Ambiente' for providing financial support for the present work through the programme of 'Optimización de Recursos' and to the 'Laboratorio Municipal de Salud Pública'. ; Peer Reviewed

8 Páginas.-- 6 Figuras ; The current great concern about plastic pollution opens up opportunities for the production of more sustainable polymers. Inverse vulcanization has emerged as a novel procedure to obtain inorganic-organic hybrid polymeric materials. Sulfur is attained as a by-product of oil refining production and makes inverse vulcanization a sustainable process due to a large amount of sulfur without a useful life. In previous studies, vegetable oils were used as a comonomer with sulfur to form copolymers based on sustainable raw material. Nevertheless, compounds from agro-wastes, could be a third comonomer that improves new copolymers bio-applications. In this study, a new series of copolymers with castor oil as vegetable oil and sulfur was formulated by adding a third compound bearing double bonds or heteroatoms. A study was conducted to assess the antimicrobial capacity and antioxidant activity of the copolymers obtained to demonstrate the benefits of adding a new comonomer to improve their bioactivity. ; The authors are grateful to the Regional Government of Andalusia, Junta de Andalucía, Consejería de Economía y Conocimiento and University of Huelva (Project UHU-1257728). ; Peer reviewed