La Real Armada y el mundo hispánico en el siglo XVIII

La coordinación de este libro estuvo a cargo de Agustín Guimerá Ravina y Olivier ChalinePeer reviewe

Nitrogen removal in domestic wastewater. Effect of nitrate recycling and COD/N ratio

A denitrification/nitrification pilot plant was designed, built and put into operation, treating the effluent of an anaerobic reactor. The operation of the plant examined the effect of the nitrate recycling and the COD/N ratio on the nitrogen and the remaining organic matter removal at 18 °C. The system consisted of a two-stage treatment process: anoxic and aerobic. The hydraulic retention time (HRT) of the system was 1 h for the anoxic bioreactor and 2 h for the aerobic one. The increase in the nitrate recycling ratio did not cause a significant improvement in the nitrogen removal due to the insufficient carbon source. The wastewater to be treated had a C/N ratio of 1.1 showing a lack of organic carbon. The addition of methanol was a key point in the denitrification process used as a model for the traditional wastewater by-pass in the WWTP. The maximum nitrogen and organic matter removal (87.1% and 96%, respectively) was achieved with a nitrate recycling ratio of 600% and a C/N of 8.25, adjusted by methanol addition.Cadagua S.A. company, the European Regional Development Fund, the IPT-2011-1078-310000 project,and the INNPACTO 2011 program of the Ministry of Economy and Competitivenes

Rejection of endocrine disrupting compounds (bisphenol A, bisphenol F and triethyleneglycol dimethacrylate) by membrane: technologies

Application of membrane technologies as treatment for wastewater has grown in recent years. Accordingly, this study aimed to determine the retention capacity of these technologies for high concentrations of non-charged organic molecules such as endocrine disrupters (bisphenol A, bisphenol F and triethyleneglycol dimethacrylate or TEGDMA), which are frequents in industrial wastewater and landfill leachate. Two modes of treatment were tested, the first consisting of a microfiltration module and an ultrafiltration module working in parallel, and the second consisting of a reverse osmosis module. The system was fed with treated and macrofiltered wastewater containing high concentration of each one of the assayed endocrine disrupters. Performance of the modules was variable and in each case dependent on the type of substance to be treated. Micro- and ultrafiltration membranes demonstrated certain effectiveness at retaining the three compounds owing to association with particulate material, which is retained efficiently by these systems. The reverse osmosis membranes achieved better results for bisphenol A than for TEGDMA, which is more insoluble and of larger molecular size, indicating that mechanisms other than size-based exclusion intervene in the process. Concentration of the compound in the influent also affected retention capacity. In the trials, bisphenol F was applied in higher concentrations than the other compounds and this led to higher concentrations of bisphenol F in the effluent. In all cases high concentrations of the assayed endocrine disrupters were still found in the treated effluents, casting doubt on the suitability of membrane technologies for removing these kinds of substances when high concentrations are presented in the influent to be treated