School of Engineering & Architecture

Growth and economic performance of Nile tilapia (Oreochromis niloticus) fed on black soldier fly larvae raised on human fecal sludge and organic waste: a circular economy approach

Thu, 01 Jan 2026 00:00:00 GMT

Growth and economic performance of Nile tilapia (Oreochromis niloticus) fed on black soldier fly larvae raised on human fecal sludge and organic waste: a circular economy approach Wambugu, Anne; Gikunda, George; Riungu, Joy Nyawira; Kirimi, James; Karanja, Stephen With increasing population growth, sustainable waste management remains a global challenge. This study evaluated the effects of using defatted black soldier fly larvae meal (BSFLM) instead of fishmeal (FM) on the growth performance of Nile tilapia (Oreochromis niloticus). The black soldier fly larvae were reared using fecal sludge and organic waste as substrates, harvested at the prepupal stage, and then defatted. Three isonitrogenous diets (30% crude protein) were formulated in which BSFLM substituted FM at 0% (control, diet 1), 50% (diet 2) and 100% (diet 3) on a protein basis. A 90-day feeding trial was conducted using 270 Nile tilapia fingerlings (9.62 ± 0.22 g) in a completely randomized design. The fingerlings were distributed into three groups of three replicates (30 fingerlings per net hapa). There was a decrease in final body weight (47.73, 42.98 and 34.57 g) with increased substitution of BSFLM for diets 1, 2 and 3, respectively (p = 0.018). Diet 2 exhibited the highest survival rate (95.56%). The economic profit index recorded for diets 1 and 2 was not significantly different. Based on these results, BSFLM can effectively replace fish meal by 50%, with no detrimental effect on growth

Black Soldier Fly Larvae Meal Enhance Nutrients Composition in Diets for Nile tilapia (Oreochromis niloticus)

Tue, 01 Sep 2026 00:00:00 GMT

Black Soldier Fly Larvae Meal Enhance Nutrients Composition in Diets for Nile tilapia (Oreochromis niloticus) Wambugu, Anne; Riungu, Joy Nyawira; Kirimi, James G.; Karanja, Stephen The study evaluated the potential of defatted black soldier fly larvae meal (BSFLM) as a sustainable alternative to fish meal (FM) in Nile tilapia (Oreochromis niloticus) diets while promoting organic waste valorisation through a circular economy approach. Black soldier fly larvae (BSFL) (Hermetia illucens) were reared on faecalsludge and organic waste, harvested at the pre-pupal stage, and defatted to produce a protein rich feed ingredient. Three isonitrogenous diets (30 % crude protein) were then formulated such that BSFLM substituted FM at 0% (control, diet 1), 50% (diet 2) and 100% (diet 3) on a protein basis. Nutritional chemical analysis on ingredients and diets were determined while diets’ fatty acids profile was determined by MPA FT-NIR spectrometer. The analysis showed significant differences (p < 0.05) among the diet treatments for all measured parameters except dry matter. FM registered the highest crude protein, (57.89%) followed closely by defatted BSFL (54.69%). However, partial substitution of FM with defatted BSFL in diets increased crude protein levels (31.77%), registered moderate crude fat (5.26%) and moderate crude fibre (11.08%) (diet 2) levels compared to FM meal diet (diet 1). Consequently, partial substitution yielded the highest overall polyunsaturated fatty acids (ƩPUFAs) content (4.81 mg/g). Thus, the study shows that, partial replacement (50%) of FM with defatted BSFLM provides rich proximate and fatty acid profiles that can support Nile tilapia production while sustainably managing waste, promoting resource recovery within a circular economy.

The Influence of Social Factors on the Promotion of Safe Fecal Management in Flood-Prone Areas: A Case of Nyando Sub-County, Kenya

Mon, 01 Jan 2024 00:00:00 GMT

The Influence of Social Factors on the Promotion of Safe Fecal Management in Flood-Prone Areas: A Case of Nyando Sub-County, Kenya Onyango, Reagan Omondi; Mugambi, George; Muriungi, Robert; Mworia, Lilian Sustainable Development Goal No. 6 target 2 aims to provide universal access to sanitation by the year 2030. The study aimed to investigate the influence of social factors on the promotion of safe fecal management in Nyando Sub-County. The area was selected due to prevalent flooding which led to the collapse of pit latrines stemming open defecation and reversal in sanitation access. The study employed a convergent methods approach that incorporated both quantitative and qualitative techniques. A sample size of 177 households was chosen as a representative of the 38,460 total households in the study area. Structured questionnaires and focus group discussions were used for data collection. SPSS version 26 was used to analyze quantitative data and the relationship between the variables was examined using Pearson’s Product Moment correlation at a 5% significance level. Similarly, MAXQDA software was used to group coded data from qualitative methods into themes. From the results, household wealth and gender roles had the strongest influence on the regressor variable with correlation coefficients of (r =.722**; P ≤.022) and (r =.687**; P ≤.049) respectively. Additionally, the study revealed that 18.4%, (n=30) of the respondents did not have toilets and 55.2%, (n=90) of the toilets were unimproved. In conclusion, the choice of affordable sanitation solutions incorporating the aspects of gender may increase sanitation access during floods. Future studies should therefore focus on other factors affecting the promotion of safe fecal management in Nyando Sub-County and suitable sanitation solutions for floodable environments.

Social-Cultural Factors Influence on Management of Shared Sanitation, in Nakuru Town West Slums

Thu, 01 Aug 2024 00:00:00 GMT

Social-Cultural Factors Influence on Management of Shared Sanitation, in Nakuru Town West Slums Kipngeno, Aaron; Kubai, Patrick; Mutembei, Josephine Abstract:- Sustainable Development Goal (SDG) target 6.2 calls for 'adequate and equitable sanitation for all.' However, rapid urbanization in developing countries has led to the growth of slums, where access to private toilets is impractical. Evident studies showed that shared toilets are more often poorly managed with adverse harmful health risks such as diarrheal diseases, environmental pollution, and economic deprivations. The study's specific objective was to establish social-cultural factors influencing the management of shared sanitation in Nakuru Town's west slums, Nakuru County, Kenya. The study adopted a convergent parallel mixed-method design involving 288 household heads selected through a cluster and random sampling technique. Data was collected using a structured questionnaire and interview guides. Descriptive statistics and inferential statistics was computed. The study findings indicated that the majority, 74.7%, of shared sanitation was poorly managed. The study established statistically significant associations of secondary education (p=0.024), marital status (p=0.025), user satisfaction (p=0.001), household sharing (p=0.000), social norms (p=0.001), cultural beliefs (p=0.002), Rituals on use and cleaning toilet (p=0.038), Privacy and modesty concerns (p=0.002) and management of shared sanitation. In conclusion, a large proportion of households in slums used poorly managed shared sanitation due to the influence of multiple factors like users' satisfaction, Household sharing, marital status, social norms, and cultural beliefs, thus polluting the public health of the place. The study recommended that the Government and all other agencies implementing sanitation promotion interventions should understand the social-cultural practices of the target communities and articulate this knowledge to tailor sanitation initiatives effectively. Future studies should focus on implementing and assessing the effectiveness of behavioral interventions.