Demographic structure and level of exploitation of Pellonula leonensis in the Aghien lagoon were examined by applying length-weight relationship (LWR), Condition factor, Von Bertalanffy model, Mortality parameters, Exploitation rate, Recruitment pattern and Beverton and Holt analysis. Fish population were sampled monthly during one year between June 2014 and May 2015 from artisanal and experimental captures in the Aghien Lagoon. Except LWR and the condition factor, studied parameters were provided by the FiSAT II package. The negative allometric growth (b = 2.61) was reported for Pellonula leonensis. Mean values of the condition factor (CF) vary significantly from one month to another (Anova, p ˂ 0.05). Concerning growth parameters, results indicated that the asymptotic length (L∞) has been estimated at 126.84 mm SL, growth coefficient (K) was 0.67 year -1 and growth performance index (Φ') was 2.03. Growth modelization revealed 4 cohorts for Pellonula leonensis. The estimates of the total (Z), natural (M) and fishing (F) mortalities were 1.87, 0.92 and 0.95 year -1 respectively. The recruitment pattern was continuous throughout the year with two Gauss curve. The exploitation rate obtained (E = 0.51) was close to E0.1 (E0.1 = 0.55), thus indicating that the P. leonensis stock is in an optimum state of exploitation.

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.

The section of the Bandama River located in Haut-Bandama Wildlife Reserve was subject to several pressures induced by the anthropic activities that take place there. These activities could have impacts on the structure of biological communities such as aquatic insects which are indicators of the state of the ecological integrity of the environment. This study was conducted to evaluate the diversity and structure of the aquatic entomofauna of this part of Bandama River. Sampling was conducted from January 2018 to February 2019 at 06 sites defined according to the upstream-downstream gradient of the river. Insects were collected using a handled net and aVan Veen bucket. The inventory identified 127 species from 53 families and 10 orders. In this part of Bandama River, the order Hemiptera was the most prevalent with 30 species. The taxa Gerisella sp. (31% of individuals), Dineutus sp. (55%), and Laccophilus sp. (38%) wereabundant in the upstream, median and downstream sections of Bandama River respectively. Also, 33 species were common to all stations. Thraulus sp. AndLispe sp. wereonly found at station BYB, located downstream of this sectionof Bandama River. The distribution of entomofauna was influenced by pH, turbidity, dissolved oxygen, speed, depth and temperature. The entomological populations in this part of the Bandama River were well diversified and with awell balanced organisation.