Browsing by Author "Lyimo, Thomas"

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Bacterial communities structure in constructed wetlands for municipal and industrial wastewater treatment in Tanzania
(IWA Publishing, 2023) Msaki, Gerubin; Kaale, Sadikiel; Njau, Karoli; Lyimo, Thomas
Bacteria are the largest and most essential microorganisms in wastewater treatment systems. Despite the vital role bacteria play in enhancing wastewater treatment, its community structure and diversity remain poorly known. This study elucidated bac- terial diversity and community structure in constructed wetlands (CWs) for municipal and industrial wastewater treatment using a culture-independent approach. Analysis of physicochemical parameters and Illumina high-throughput sequencing of V3 and V4 hypervariable regions of 16S rRNA gene bacterial community was performed. The results showed that the Proteobacteria were dominant (48.66%) phyla across all CWs. The Gammaproteobacteria class (27.67%), family Comamonadaceae (35.79) and Genus Flavobacterium (4.35%) were dominant across studied CWs. Bacterial abundance increased from the inlet to the outlet, with CWs having a higher abundance around the outlet, showing a good performance. The Shannon–Wiener index showed the highest species diversity (H ¼ 1.45) in Banana Investment Limited CWs treating industrial wastewater. This study found significant bacterial diversity across studied CWs, with higher abundance and diversity at the outlet indicating better per- formance than those with low abundance and diversity at the outlet. We recommend a longitudinal investigation at each CWs section to confirm and establish the role of bacterial diversity on the performance pattern of CWs.
Characterization of bird, reptile, and insect community diversity in constructed wetlands and waste stabilization ponds across Tanzania
(Elsevier, 2023-11) Msaki, Gerubin; Njau, Karoli; Treydte, Anna; Lyimo, Thomas
Wastewater treatment systems, such as Constructed Wetlands (CWs) and Waste Stabilization Ponds (WSPs), have untapped biodiversity enhancement and development potential. Birds, insects, and reptiles, which are displaced by human development, might find refuge in these ecosystems. However, the lack of a detailed characterization of the biodiversity status of these wastewater treatment systems hinders their widespread adoption. Point counts, direct observations, and camera traps were used to assess bird diversity across five CWs and three WSPs in Tanzania in 2021. For insects and reptiles, pitfall and pan traps were laid along established transects, in addition, direct observations and fishnets were also used to assess the reptiles dwelling within the WSPs. Abundance, Shannon index, Simpson index, Margalef index, and evenness index were the diversity parameters used to analyze the diversity of birds, insects, and reptiles. Our results show that among the studied groups and between WSPs and CWs, birds had high species abundance (n = 1132), richness, Margalef index (D = 4.266), evenness (E = 0.815), Shannon diversity (H = 2.881) and Simpson index (λ =0.903). The abundance and diversity of studied groups differed significantly (P < 0.05) between WSPs and CWs. Our study also recorded four reptile species belonging to three orders. Molecular analyses confirmed that insect species belong to nine orders and 13 families, with the order Diptera dominating both CWs and WSPs, followed by Orthoptera, Hymenoptera, and Araneae. We conclude that CW and WSP wastewater treatment systems are important for hosting various populations of birds, reptiles, and insect species.
Social knowledge, attitudes, and perceptions on wastewater treatment, technologies, and reuse in Tanzania
(IWA Publishing, 2022-06-01) Msaki, Gerubin; Njau, Karoli; Treydte, Anna; Lyimo, Thomas
This study assessed the social knowledge, attitude, and perceptions (KAPs) on wastewater treatment, the technologies involved, and its reuse across different wastewater treatment areas in four regions of Tanzania. We used both quantitative and qualitative data collection methods in a household-level questionnaire (n=327) with structured and semi-structured questions, which involved face-to-face interviews and observation. Our results show that social KAPs surrounding wastewater treatment and reuse were sufficient based on KAP scores achieved from asked questions. However, the general knowledge on treatment technologies, processes, and reuse risks was still low. Of the respondents, over 50% approved using treated wastewater in various applications, while the majority (93%) were reluctant if the application involved direct contact with the water. Furthermore, over 90% of interviewees did not know the technologies used to treat wastewater and the potential health risks associated with its use (59%). Multivariate analysis of variance revealed significant differences (P<0.05) in the KAPs on treated wastewater across different studied demographic variables, i.e., age, sex, and education level. Therefore, we recommend that more effort be spent on providing public education about the potential of wastewater treatment and existing technologies in order to facilitate their adoption for the community's and environment's benefit.