The taxonomic diversity and structure of benthic macroinvertebrates of Taabo Lake (Ivory Coast), from November 2017 to October 2018 were evaluated. Water quality parameters, such as temperature (T °C), water transparency (cm), dissolved oxygen (mg.L-1), pH, turbidity (NTU), electrical conductivity (EC, µS.cm-1) were measured in situ using a multi-parameter probe HANNA, from four sampling points (littoral and sub-littoral zones) in Taabo Lake. Benthic macroinvertebrates sampling were collected by using Van veen in stainless steel. A total of 63 benthic macroinvertebrates taxa belonging to 23 Families, 8 Orders, 2 Classes and 2 Phylums (Molluscs and Arthropods) were identified. The most abundant of benthic macroinvertebrates were Mesogastropoda (66%) represented in all sampling points. They were followed by Diptera (25%), Odonata (3%), Ephemeroptera (3%), Basommatophora (2%), Heteroptera (1%), Lepidoptera and Coleoptera (less than 1%). The values of diversity indices of benthic macroinvertebrates collected in Taabo Lake showed no significant variations between sampling points.

The composition, structure and Functional Feeding Groups (FFGs) of aquatic insects were investigated in Kodjoboué lake (South-East of Côte d'Ivoire) to assess water quality. Four sites (K1 -K4) were sampled during eight campaigns. At each site aquatic insects were collected using a kick-net (25 × 20 cm, 500 µm mesh size). Environmental variables were also recorded during this period. Water was collected from each sampling site for nutrient (phosphorus, nitrate) analysis in laboratory. A total of 68 aquatic insect taxa belonging to six orders and 32 families were recorded during the study. Site K4, subject to intense agricultural activity, had the lower diversity and least balanced stand with the lowest values of Shannon-Weaver index, Pielou's Evenness index and rarefied richness. The functional approach revealed five major FFGs: predators, scrapers, shredders, gatherers-collectors and filter-collectors. Among the different functional feeding groups, the percentage of predators was higher than that of other groups at all the sites. The P/R report indicated that our four sites are characterized as heterotrophic with K1 as the least heterotrophic. Focused Principal Component Analysis (FPCA) showed that parameters of water, like pH, dissolved oxygen, nitrate were statistically correlated with species abundance. The diversity and Functional Feeding Groups metrics of aquatic insects used to describe the state of Kodjoboué lake reveal its disturbed state.

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This study evaluates the performance of shale from Ivory Coast used as substrate in vertical-flow constructed wetlands in removal of phosphates and nitrogen. The pilot-scale artificial wetland has been duplicated: filter planted with Panicum maximun and unplanted. They were set up outdoors, and fed with a municipal wastewater. The wetlands have been fed with three batches per week (intermittent) over a period of 3 months. During the operation period, the hydraulic residence time (HRT) 52 h was used, while wastewater temperatures varied from about ~33˚C. The removal performance of the constructed wetland units was very good, since it reached on an average 98%, 89.4%, 89.4%, 84%, 80%, 84.8% and 92% for TSS, DOC, BOD 5 , 4 NH + , TKN, TP and 3 4 P-PO − respectively. In addition, the vegetation did not demonstrate superior performance to unplanted controls. Therefore, this study focuses on the role of shale in the phosphorus and nitrogen removal from wastewater by constructed wetland.