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This study aimed to evaluate the effect of initial moisture content on the in-vessel composting under air pressure of organic fraction of municipal solid waste in Morocco in terms of internal temperature, produced gases quantity, organic matter conversion rate, and the quality of the final composts.For this purpose, in-vessel bioreactor was designed and used to evaluate both appropriate initial air pressure and appropriate initial moisture content for the composting process. Moreover, 5 experiments were carried out within initial moisture content of 55%, 65%, 70%, 75% and 85%. The initial air pressure and the initial moisture content of the mixture showed a significant effect on the aerobic composting. The experimental results demonstrated that for composting organic waste, relatively high moisture contents are better at achieving higher temperatures and retaining them for longer times.This study suggested that an initial moisture content of around 75%, under 0.6 bar, can be considered as being suitable for efficient composting of organic fraction of municipal solid waste. These last conditions, allowed maximum value of temperature and final composting product with good physicochemical properties as well as higher organic matter degradation and higher gas production. Moreover, final compost obtained showed good maturity levels and can be used for agricultural applications.

2015): Characterization, structure, and function of extracellular polymeric substances (EPS) of microbial biofilm in biological wastewater treatment systems: a review, Desalination and Water TreatmentTo link to this article: http://dx. A B S T R A C TA review concerning the definition, extraction, characterization, production, and functions of extracellular polymeric substances (EPS) of microbial aggregates in biological wastewater treatment reactors is given in this paper. EPS are a complex high-molecular-weight mixture of polymers excreted by microorganisms, produced from cell lysis and adsorbed organic matter from wastewater. The EPS fill and form the space between the biofilm constituents, e.g. prokaryotic and eukaryotic microorganisms which inhabit the aggregates. It seems that the EPS matrix may serve as a multipurpose functional element of microbial communities, including adhesion, structure, protection, recognition, and physiology. Due to the metabolic activity of the cells, gradients develop and create different habitats within small distances, allowing a wide variety of organisms to settle and grow in the aggregate. As many of these organisms produce their specific EPS, it is not surprising that an extremely wide variety of microbial aggregates result. All of them have in common their highly hydrated extracellular matrix which is the place the organisms shape their very own microhabitat in which they live. However, as EPS are very complex, the knowledge regarding EPS is far from complete and much work is still required to fully understand their precise roles in the biological treatment process.