Baleba^1,2 Laurent Justinien, Moumbagna Mboutngam³ Mouhamadou, Mahot¹ Hermine Claudine, Essono³ Damien Marie, Beyegue-Djonko¹ Honoré, Koga Mang’Dobara³, Nkobe Keghe¹ Martin, Ngansop⁴ Eric, Mvondo Awono² Jean Pierre, and Mahob^3* Raymond Joseph

¹Institute of Agricultural Research for Development (IRAD), P.O Box 2067, Yaoundé, Cameroon, ² Department of Crop Sciences, University of Dschang, P.O Box 222, Dschang, Cameroon, ³Faculty of Science, University of Yaoundé I, P.O Box 812, Yaoundé, Cameroon, ⁴National Herbarium of Cameroon (HNC), IRAD, P.O Box 1601, Yaoundé

*Corresponding author E-mail: raymondmahob@gmail.com; Tel.: (+237) 679 18 76 46/695 92 62 00

Abstract

The study aimed to assess the biodiversity, ecological status and farmers’ use/perception of non-coffee plants species (NCPS) in contrasting locations, due to the lack of these valuable data regardless of agroecological services and/or environmental conservation. Thus, investigations through the transverse study have been carried out within 17 Robusta coffee plantations, 7 villages and 3 sub-divisions of Noun Division. NCPS were identified using relevant dichotomous keys whereas their recovery rate was estimated via Braun-Blanquet method. Biodiversity of NCPS was estimated using the specific richness and/or diversity indices while their ecological status and farmers’ use/perception were determined through Dajoz (1982) modified method and structured questionnaires respectively. In total, 48 NCPS divided into 38 genera and 17 families were inventoried. Elaeis guineensis revealed most frequent species, with 30.85% of occurrence while Albizia adianthifolia, A. glaberrima, Antidesma laciniatum, Citrus medica, C. sinensis, Erythrophleum suaveolens, Ficus mucuso, F. polita, F. umbellata, Macaranga sp., Mangifera foetida, Piptadeniastrum africana, Pterocarpus erinaceus, P. milbraedii, Pycnanthus angolensis, Sarcocephalus diderrichii, Sterculia tragacantha, Trilepisium madagascariense and Voacanga africana, were found scarce, with 0.25% of occurrence each. NCPS circumference and recovery rate varied significantly (p<5%) between the studied plots, from 64.75 ± 3.17 to 181.86 ± 43.81 cm and 8% to 100% respectively. Plants abundance and specific richness/diversity also varied between plots, villages and sub-divisions, with respective values of 2 to 44 individuals, 28 to 117 and 91 to 177 (for abundance) versus 0.00 to 3.34, 0.57 to 5.04 and 0.58 to 7.54 (for specific richness/diversity). 66.66% of inventoried NCPS were abundant and 33.34% were extremely rare. According to the respondents, NCPS have different status/functions: 89.47%, 34.21%, 23.68 and 7.89% serve as shade trees, timber, therapeutic purposes/food, and soil enrichment respectively. Our findings revealed the need to take appropriate measures to preserve endangered species for sustainability environmental conservation of the studied agrosystems.

Keywords: Specific richness/diversity, associated perennial trees, Robusta Coffee Agrosystems, environmental conservation, ecosystem services

Biological and physicochemical characterization of wastewater in an anthropogenic zone          

Asi Quiggle Atud^[1]*, Zoua  Vincent de Paul ^[1],  Visiy Edna Buhnyuy ^[1]

^[1] Ecole Nationale Supérieure des Travaux Publics, BP 510, Département de Génie de l’Environnement, Yaoundé Cameroun

       * Correspondance: asiatud@yahoo.com                                                                      

             ORCID iD: 0000-0002-2658-3684

Résume

Dans le but d’évaluer le devenir des parasites lors du cycle de traitement des eaux usées, les échantillons ont été prélevés à l’entrée et à la sortie dans deux stations de traitement des eaux usées. Les analyses physicochimiques et le taux d’abattement ont été réalisés par les méthodes standards. Les analyses biologiques ont été réalisées par les techniques de sédimentation, Ziehl-Neelsen modifiée et les Trichrome de Weber. Les résultats montrent que les taux d’abattement de la Matière organique (77.18%), de la  DBO₅ (99.33%) et  MES (95.72%) sont relativement élevés. Alors que les valeurs de  l’oxygène dissous et la résistivité indicateurs de la qualité des eaux sont élevés au niveau des stations de sortie. L’analyse parasitologique de ces eaux usées a montré que, ces eaux contiennent plusieurs types de parasites caractérisées par une diversité de formes et d’espèces notamment les formes des oocystes, des kystes et des spores de Protozoaires ( Cryptosporidium spp., Entamoeba histolytica, Giardia intestinalis, Microsporidium…) ainsi que des œufs et des larves d’ Helminthes pathogènes (Ascaris sp., Hymenolepis nana, Trongyloides sp…). L’abattement des spores, oocystes, kystes, œufs et larves sont respectivement croisant de 53 %, 76 %, 80 %, 100 % et 100 %. Le taux d’élimination d’Helminthes plus important, serait lie à la sédimentation et pouvoir de résistance faible contrairement  aux Protozoaires de petite taille et plus résistants. Ces résultats démontrent des améliorations des qualités physicochimiques et biologiques des organismes de grandes tailles à la sortie avec une meilleure performance à la station de Messa.  L’efficacité de ces centres d’épuration des eaux usées serait d’avantage plus optimisée  en associant une station tertiaire pour désinfection des parasites  de forte capacité de résistance qui échappent les mailles de traitement secondaire. Cette étude ressort en plus, l’intérêt d’intégrer les spores microsporidiennes plus résistantes, caractéristiques de bio indicateur pour l’évaluation et le contrôle de la qualité d’eau  en conformité avec les normes des rejets des eaux usées.

Mots clés Eaux usées domestiques. Parasites. Taux d’abattement. Physicochimie. Eaux épurées. Station d’épuration. Yaoundé

Abstract

In order to assess the fate of parasites and the effectiveness of wastewater treatment, samples were taken at the inlet and outlet of two wastewater treatment technology. The physicochemical analysis and the abatement rate were carried out using standard methods. Biological analysis were carried out using sedimentation, modified Ziehl-Neelsen and Weber Trichrome technique. The results show that the abatement rates of Organic Matter (77.18%), BOD₅ (90.33%) and suspended solids (95.72%) are relatively high. While the dissolved oxygen values and resistivity, indicators of water quality, are high at the outlet stations.  The parasitological analysis of this wastewater has shown that this water contains several types of parasites characterized by a diversity of forms and species, including the forms of oocysts, cysts and spores of Protozoa ( Cryptosporidium spp., Entamoeba histolytica, Giardia intestinalis, Microsporidium, etc.). as well as eggs and larvae of pathogenic Helminths (Ascaris sp., Hymenolepis nana, Trongyloides sp….). The reduction of spores, oocysts, cysts, eggs and larvae is 53%, 76%, 80%, 100% and 100% respectively. The Helminth Elimination Rate more important, would be linked to sedimentation and weak resistance power unlike the small size of  Protozoa that is  more resistant. These results demonstrate improvements in the physicochemical and biological qualities of large organisms at the outlet with a better performance at the Messa station.  The efficiency of these wastewater treatment technologies would be further optimised by combining a tertiary station for disinfection of parasites with a high resistance capacity that escapes the secondary treatment meshes. This study also highlights the interest of integrating microsporidian spores, more resistant and characteristics of bio indicator for the evaluation and control of water quality in accordance with wastewater discharge standards.

Keywords  Domestic wastewater. Parasites. abatement rate.  Physicochemical parameters. Purified water. Wastewater treatment technology. Yaounde