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Microbiological water quality of the Mfoundi River watershed at Yaoundé, Cameroon, as inferred from indicator bacteria of fecal contamination Djuikom, E.; Njine, T.; Nola, M.; Sikati, V.; Jugnia, L.-B. Abstract. Using the membrane filtration technique to count total coliform (TC), fecal coliform (FC) and fecal streptococci (FS), the microbiological water quality of the Mfoundi River and four of its representative tributaries at Yaoundé, Cameroon, was assessed for human use and contact. Sampling was conducted so as to examine the potential origin of fecal contamination and how rainfall affects the measured concentrations of indicators organisms. Our results revealed that waters were not safe for human use or primary contact according to the standards for water quality established by the Word Health Organization (WHO). Indeed, these waters exhibited high concentrations of TC (Mean ± SD = 5.6 × 10 8 ± 2.5 × 10 6 CFU/100 ml), FC (Mean ± SD = 6.8 × 10 5 ± 2.4 × 10 3 CFU/100 ml) and FS (Mean ± SD = 7.3 × 10 5 ± 2.1 × 10 3 CFU/100 ml) that varied with the sampling sites and points. FC/FS ratio suggested that this contamination was more from warm-blooded animals than humans and correlation analysis points to the role of rainfall as a contributing factor, which enhanced the bacterial numbers detected. We conclude that there is a great potential risk of infection for users of waters from the Mfoundi River and its tributaries at Yaoundé.

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An experimental passive methane oxidation biocover (PMOB) was constructed within the existing final cover of the St-Nicéphore landfill. Its substrate consisted of a 0.80-m thick mixture of sand and compost. The goal of this experiment was to evaluate the performance of the PMOB in reducing CH 4 emissions when submitted to an increasing methane load. The CH 4 load applied started with 0.3 g CH 4 m −2 h −1 . When the site had to be closed for the winter, the CH 4 input was 27 g CH 4 m −2 h −1 . Throughout the study, practically all the CH 4 input was oxidized, absolute removal rates were linearly correlated to methane loading, and the oxidation zone was established between 0.6-0.8 m. These results seem to indicate that the upper limit potential of this PMOB to oxidize CH 4 was not reached during the study period. Surface CH 4 concentration scans showed no signs of leaks. The substrate offered excellent conditions for the growth of methanotrophs, whose count averaged 3.91 x 10 8 CFU g dw -1 soil.