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There are numerous studies on two-phase anaerobic digestion of municipal solid waste (MSW) in the literature. Yet, in the majority of these studies, applied organic loading rates (OLR) were relatively low. This study differs from those in the literature in terms of high OLR application and focuses on the optimization of the acidification phase. Effect of high OLRs and pH values were investigated and optimum operational conditions for acidification were determined. Although conversion of particulate organics to soluble chemical oxygen demand (COD) was achieved in the reactors, total COD values remained the same. Various types of organic acids were produced in the reactors and the selective production of organic acids in the anaerobic acidogenesis process was possible by controlling the organic loading rate and pH. Optimum OLR and pH values were determined as 15 g volatile solid (VS)=L Á day and 5.5 AE 0.1, respectively, for the MSW composition investigated.

We have developed a 6 dm 3 -sized optical instrument to characterize the microphysical properties of fine particulate matter or aerosol in the Earth atmosphere from low Earth orbit. Our instrument can provide detailed and worldwide knowledge of aerosol amount, type and properties. This is important for climate and ecosystem science and human health [1,2]. Therefore, NASA, ESA and the European Commission study the application of aerosol instruments for planned or future missions. We distinguish molecular Rayleigh scattering from aerosol Mie-type scattering by analyzing multi-angle observations of radiance and the polarization state of sun light that is scattered in the Earth atmosphere [3]. We measure across the visible wavelength spectrum and in five distinct viewing angles between -50° and +50°. Such analysis has been traditionally done by rotating polarizers and band-filters in front of an Earth observing wide-angle imager. In contrast, we adopt a means to map the linear polarization state on the spectrum using passive optical components [4]. Thereby we can characterize the full linear polarization state for a scene instantaneously. This improves the polarimetric accuracy, which is critical for aerosol characterization, enabling us to distinguish for example anthropogenic from natural aerosol types. Moreover, the absence of moving parts simplifies the instrument, and makes it more robust and reliable. We have demonstrated this method in an airborne instrument called SPEX airborne [5,6] in the recent ACEPOL campaign together with a suite of state-of-the art and innovative active and passive aerosol sensors on the NASA ER-2 high-altitude research platform [7]. An earlier report on the SPEX development roadmap was given in [8]. In this contribution we introduce SPEXone, a compact space instrument that has a new telescope that projects the five viewing angles onto a single polarization modulation unit and the subsequent reflective spectrometer. The novel telescope allows the observation of five scenes with one spectrometer, hence the name. We describe the optical layout of the telescope, polarization modulation optics, and spectrometer and discuss the manufacturability and tolerances involved. We will also discuss the modelled instrument performance and show preliminary results from optical breadboards of the telescope and polarization modulation optics. With SPEXone we present a strong and new tool for climate research and air quality monitoring. It can be used to study the effect of atmospheric aerosol on the heating/cooling of the Earth and on air quality. Also, SPEXone can improve the accuracy of satellite measurements of greenhouse gas concentrations and ocean color that rely on molecular absorption of reflected sunlight by providing detailed knowledge of the aerosol properties, required to accurately trace the light path in presence of scattering. SPEXone is developed in a partnership between SRON Netherlands Institute for Space Research and Airbus Defence and Space Netherlands with support from the Netherlan...

The organic fraction of municipal solid waste can be a significant energy source for renewable energy generation. The total production of municipal solid waste in Turkey was 25 Â 10 6 tones per year. Anaerobic digestion (AD) process may be a solution to the problems of energy demand and waste management since it provides biomethanation along with waste stabilization. AD can be operated in single or two phase configurations. Two-phase processes have some advantages over one phase systems in terms of selection of microorganisms, process efficiency, and reactor size. In this study, biochemical methane production experiments were performed in order to investigate whether phase separation enhanced the efficiency of methanogenic activity or not. The performances were compared in terms of total chemical oxygen demand (tCOD) and volatile solids (VS) reductions, and cumulative gas production. The experimental results indicated that 10% and 23% increases in tCOD and VS removals were achieved, respectively, by phase separation. The acetic and propionic acids were not detected in the reactors, which was an indication of successful methanization. V C 2012 American Institute of Physics. [http://dx.