La lagune Aghien est une lagune périurbaine sujette à plusieurs types de pressions anthropiques. Ces pressions pourraient avoir des répercussions sur les communautés biologiques qui peuvent être des indicateurs de l’état de qualité écologique de cette lagune. Parmi ces communautés biologiques, il y a les mollusques qui sont potentiellement capables de coloniser la zone profonde des systèmes lagunaires et lacustres. L’objectif de cette étude était d’évaluer l’état biologique du sédiment de la lagune Aghien à partir de l’Indice Malacologique de qualité des systèmes Lacustres (IMOL). Sur chaque station, l’échantillonnage du sédiment, a été réalisé en raison de trois échantillons de sédiments prélevés avec la benne Van Veen. Au total 10 taxons appartenant à 7 genres de mollusques ont été collectés dans le sédiment des différentes stations de la lagune Aghien. Selon l’IMOL, cinq stations sur les onze indiquent un état biologique moyen. L’état biologique du sédiment est connu et présente un état biologique globalement moyen. L’IMOL peut être utilisé pour évaluer les eaux lentiques ayant 10 mètres de profondeur maximale English title: Biological state of the sediment of the Aghien lagoon from the Malacological Quality Index of Lacustrine Systems (IMOL) (South-east, Ivory Coast) The Aghien lagoon is a peri-urban lagoon subject to several types of anthropogenic pressures. These pressures could have effects on biological communities which may be ecological quality status indicators. Among these biological communities, mollusc’s which are likely to colonize the deep zone of lagoon and lake systems. This study was carried out to assess the biological state of Aghien lagoon sediment from the malacological index of lake systems (IMOL). At each station, sediment sampling was performed due to three sediment samples taken with the Van Veen grab. A total of 10 taxa belonging to 7 kinds of molluscs were collected in the sediment of the various stations. According to IMOL, five of the eleven stations, had an average biological state. The biological state of the sediment was known and had an average biological state.  IMOL can be used to assess lentic waters up to 10 meters deep.

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The non-saturated Flow Drying Beds allow efficient treatment of septic tank sludge. However, they are vulnerable to clogging. To ensure the sustainability of this technology, through an additional supply of oxygen from the lateral surface, a flow model coupled with the variation of the biofilm has been developed. The calibration, validation and comparison of the simulated and experimental results were made from the NASH criterion. The simulations focused on two types of reactors. A reactor with pores on its side surface is called a ventilated reactor (VR). The second is then called an unventilated reactor (UVR). The results show that the maximum applicable organic load is 43.3 mgO2 / cm2 / d at the UVR level and 51.8 mgO2 / cm2 / d at the VR level. In addition, the reduction in free flow porosity is 93.33% at the UVR level and 81% at the AR level. In addition, the results show that when the hydraulic head is less than 5 cm / d, the COD removal efficiency is 96.19% at the UVR level and 95.64% at the VR level. But, when the load is greater than 5 cm / d, the yield is 92.65% at the level of the UVR and of 94.95% at the level of the VR. Thus, in the context of a large-scale operation, lateral ventilation is essential. It guarantees good purification efficiency, slows down internal clogging of beds and accelerates its reversibility when it occurs.