HIGHLIGHTS• A comprehensive and flexible urban emission inventory was developed for Madrid.• Options for multi-scale consistency are discussed (from European to street level).• Urban background N0 2 concentration levels well described by CMAQ (MB -2.2 ug/m 3 ).• N0 2 concentration levels in Madrid are dominated by local traffic (up to 90%).• A 31% reduction of NO x emissions may allow Madrid meeting the N0 2 European standards. ABSTRACTModeling is an essential tool for the development of atmospheric emission abatement measures and air quality plans. Most often these plans are related to urban environments with high emission density and population exposure. However, air quality modeling in urban areas is a rather challenging task. As environmental standards become more stringent (e.g. European Directive 2008/50/EC), more reliable and sophisticated modeling tools are needed to simulate measures and plans that may effectively tackle air quality exceedances, common in large urban areas across Europe, particularly for N0 2 . This also implies that emission inventories must satisfy a number of conditions such as consistency across the spatial scales involved in the analysis, consistency with the emission inventories used for regulatory purposes and versatility to match the requirements of different air quality and emission projection models. This study reports the modeling activities carried out in Madrid (Spain) highlighting the atmospheric emission inventory development and preparation as an illustrative example of the combination of models and data needed to develop a consistent air quality plan at urban level. These included a series of source apportionment studies to define contributions from the international, national, regional and local sources in order to understand to what extent local authorities can enforce meaningful abatement measures. Moreover, source apportionment studies were conducted in order to define contributions from different sectors and to understand the maximum feasible air quality improvement that can be achieved by reducing emissions from those sectors, thus targeting emission reduction policies to the most relevant activities. Finally, an emission scenario reflecting the effect of such policies was developed and the associated air quality was modeled.

ARTICLE INFO ABSTRACT Keywords:Primary catalyst Sewage sludge gasification Bubbling fluidised bed Tar contentSewage sludge gasification assays were performed in an atmospheric fluidised bed reactor using air and air-steam mixtures as the gasifying agents. Dolomite, olivine and alumina are three well known tar removal catalysts used in biomass gasification processing. However, little information is available regarding their performance in sewage sludge gasification. The aim of the current study was to learn about the influence of these three catalysts in the product distribution and tar production during sewage sludge gasification. To this end, a set of assays was performed in which the temperature (750-850 °C), the inbed catalyst content (0,10 and 15 wt.%)and the steam-biomass ratio (SB) in the range of 0-1 were varied with a constant equivalence ratio (ER) of 0.3. The results were compared to the results from gasification without a catalyst. We show that dolomite has the highest activity in tar elimination, followed by alumina and olivine. In addition to improving tar removal, the presence of water vapour and the catalysts increased the content of H 2 in the gases by nearly 60%.

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ARTICLE INFO ABSTRACT Keywords:Sewage sludge gasification Primary catalyst Bubbling fiuidised bed Gasifying agenteNumerous references can be found in scientific literature regarding biomass gasification. However, there are few works related to sludge gasification. A study of sewage sludge gasification process in a bubbling fiuidised bed gasifier on a laboratory scale is here reported. The aim was to find the optimum conditions for reducing the production of tars and gain more information on the influx of different operating variables in the products resulting from the gasification of this waste. The variables studied were the equivalence ratio (ER), the steambiomass ratio (SB) and temperature. Specifically, the ER was varied from 0.2 to 0.4, the SB from 0 to 1 and the temperature from 750 °C (1023 K) to850 °C (1123 K). Althoughit was observed that tar production could be considerably reduced (up to 72%) by optimising the gasification conditions, the effect of using alumina (aluminium oxide, of proven efficacy in destroying the tar produced in biomass gasification) as primary catalyst in air and air-steam mixture tests was also verified. The results show that by adding small quantities of alumina to the bed (10% by weight of fed sludge) considerable reductions in tar production can be obtained (up to 42%) improving, at the same time, the lower heating valué (LHV) of the gas and carbón conversión.

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Adsorption methods are one of the current ways to reduce CO2 emissions. Taking this into account, sewage-sludge-based activated carbons were produced to study their CO2 adsorption capacity. Specifically, chemical activation with KOH and NaOH of previously pyrolyzed sewage sludge was carried out. The results obtained show that even with a low BET surface area, the adsorption capacity of these materials was comparable to that of a commercial activated carbon. As a consequence, the use of sewage-sludge-based activated carbons is a promising option for the capture of CO2 and an interesting application for this waste.

HIGHLIGHTS• índigo wastewaters are successfully treated with a solar assisted oxidation reaction.• Using ferrous oxalate complexes, the efficiency of the treatment increases.• Increasing peroxide concentrations did not improve the treatment substantially.• The best remováis of TOC and COD were reached with the smallest peroxide dose.• A final complete biodegradability was obtained for these wastewaters. ARTICLE INFO ABSTRACT Keywords:Advanced oxidation process Ferrous oxalate complex índigo dye Photo-Fenton BiodegradabilityThis study assessed the applicability of a ferrous oxalate mediated photo-Fenton pretreatment for indigodyed wastewaters as to produce a biodegradable enough effluent, likely of being derived to conventional biological processes. The photochemical treatment was performed with ferrous oxalate and hydrogen peroxide in a Compound Parabolic Concentrator (CPC) under batch operation conditions. The reaction was studied at natural pH conditions (5-6) with Índigo concentrations in the range of 6.67-33.33 mgL _1 , using a fixed oxalate-to-iron mass ratio (C204 2~/ Fe 2+ = 35) and assessing the system's biodegradability at low (257 mgL _1 ) and high (1280mgL _1 )FfcO2 concentrations. In order to seek the optimal conditions for the treatment of Índigo dyed wastewaters, an experimental design consisting in a statistical surface response approach was carried out. This analysis revealed that the best removal efficiencies for Total Organic Carbón (TOC) were obtained for low peroxide doses. In general it was observed that after 20 kj L _1 , almost every treated effluent increased its biodegradability from a BOD5/COD valué of 0.4. This increase in the biodegradability was confirmed by the presence of short chain carboxylic acids as intermedíate producís and by the mineralization of organic nitrogen into nitrate. Finally, an overall decrease in the LC50 for Artemia salina indicated a successful detoxification of the effluent.