Aquaculture in Ghana is experiencing tremendous growth, led mainly by large‐scale commercial cage operators. A major objective of the government and its partners is to ensure that this rapid growth ...is sustainable and includes small‐scale farmers and poor rural producers. This paper evaluates the aquaculture trainings implemented in six main tilapia‐producing regions in Ghana as part of the Ghana Tilapia Seed Project. The impact evaluation is designed as a cluster randomized controlled trial, with half of the producing districts randomly‐assigned as the treatment and the rest as the control, complemented by qualitative interviews. One year after the trainings, results show positive impacts on the adoption of good record‐keeping, water management, and some biosecurity practices, and on productivity and incomes. In terms of mechanism, improved management practices resulted from reducing overstocking, reducing inbreeding, maintaining water level for fish ponds, regular pond clearing and establishing physical barriers, following advice and recommendations on feeding practices, and complementing feeding practices with farmers’ own feed formulation. Half of the trained farmers experienced lower fish mortality, faster growth, and heavier fish at harvest. Marketing and processing advice through the trainings and complementary FishConnect WhatsApp platform likely contributed to higher incomes, although the platform's coverage and regular updating can be improved.
Over the past decade, the aquaculture sector in Ghana has experienced tremendous growth—driven mainly by large-scale cage aquaculture. Pond aquaculture, traditionally extensive and with limited ...external inputs, has been transforming over the same period. Farm profitability was wide-ranging, between −12.00 and 46.00 Ghanaian cedi (GHC) per square meter (m2), with an average of GHC 8.82/m2 for farmers active in 2019. Despite wide variability in production and profits, the majority of farmers experienced positive profits—on average, GHC 3.24 per kilogram of tilapia produced, or a 27% profit margin. Farmers who adopted good aquaculture practices and intensified their production have high productivity and positive profits. Nonetheless, the cost to produce 1 kg of tilapia in Ghana (roughly US$1.51 on average) was much higher than in other major tilapia-producing countries (averaging roughly US$0.78 to 1.29). COVID crisis further affected fish farmers: 54% experienced difficulties in accessing inputs, 56% experienced difficulties selling their fish, and farmgate fish prices went down in April–August, although slowly bounced back by end of 2020. Improving the competitiveness and resilience of Ghanaian tilapia sector will require improved seed, increased adoption of good management practices, lower-cost quality feed, and enabling policies and regulations.
•On average, a Ghanaian fish farmer received a profit of US$1.52 per m2 (27% profit margin).•The cost to produce 1-kg of tilapia (US$1.51) was higher in Ghana than in major producers.•Half of fish farmers had difficulties in accessing input and output markets in April–July 2020.•Farmgate fish prices were down in April–August, but slowly bouncing back by end of 2020.•For competitiveness and resilience, the sector needs improved seed and management practices and lower-cost quality feeds.
This study presents magnetized nanoparticles (NPs) as a catalyst to accelerate anaerobic digestion (AD) potential for clean and ecofriendly energy (biogas) from wastewater settings. The effects of ...iron oxides (Ms) and aluminum sulphate (Alum) were investigated using two chronological experiments: (i) the Jar test technique to generate residue slurry as organic fertilizer potential and (ii) a magnetized biochemical methane potential (MBMP) system for biogas production at mesophilic conditions for 21 days. X-ray diffraction and Fourier Transform Infrared spectroscopy were carried out to establish the Ms Crystallite and active functional groups respectively. Scanning electronic microscopy coupled with energy dispersive X-ray spectrometer and elemental analysis were used to track and confirm NPs inclusion after the post-AD process. Coagulation at 50 mg/L and magnetic exposure time of 30 min showed above 85% treatability performance by Ms as compared to 70% for Alum. Owing to the slow kinetics of the AD process, additional NPs content in the digesters coupled with an external magnetic field improved their performance. Cumulative biogas yields of 1460 mL/d > 610 mL/d > 505 mL/d for Ms > Control > Alum respectively representing 80% > 61% > 52% of CH4 were attained. The modified Gompertz model shows that the presence of NPs shortens the lag phase of the control system with kinetics rate constants of 0.285 1/d (control) to 0.127 1/d (Ms) < 0.195 1/d (Alum).
The coronavirus (COVID-19) pandemic is currently posing a significant threat to the world’s public health and social-economic growth. Despite the rigorous international lockdown and quarantine ...efforts, the rate of COVID-19 infectious cases remains exceptionally high. Notwithstanding, the end route of COVID-19, together with emerging contaminants’ (antibiotics, pharmaceuticals, nanoplastics, pesticide, etc.) occurrence in wastewater treatment plants (WWTPs), poses a great challenge in wastewater settings. Therefore, this paper seeks to review an inter-disciplinary and technological approach as a roadmap for the water and wastewater settings to help fight COVID-19 and future waves of pandemics. This study explored wastewater–based epidemiology (WBE) potential for detecting SARS-CoV-2 and its metabolites in wastewater settings. Furthermore, the prospects of integrating innovative and robust technologies such as magnetic nanotechnology, advanced oxidation process, biosensors, and membrane bioreactors into the WWTPs to augment the risk of COVID-19’s environmental impacts and improve water quality are discussed. In terms of the diagnostics of COVID-19, potential biosensors such as sample–answer chip-, paper- and nanomaterials-based biosensors are highlighted. In conclusion, sewage treatment systems, together with magnetic biosensor diagnostics and WBE, could be a possible way to keep a surveillance on the outbreak of COVID-19 in communities around the globe, thereby identifying hotspots and curbing the diagnostic costs of testing. Photocatalysis prospects are high to inactivate coronavirus, and therefore a focus on safe nanotechnology and bioengineering should be encouraged.
This study presents a hybridized photocatalyst with adsorbate as a promising nanocomposite for photoremediation of wastewater. Photocatalytic degradation of bromophenol blue (BPB) in aqueous solution ...under UV-irradiation of wavelength 400 nm was carried out with TiO2 doped with activated carbon (A) and clinoptilolite (Z) via the co-precipitation technique. The physiochemical properties of the nanocomposite (A–TiO2 and Z–TiO2) and TiO2 were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy. Results of the nanocomposite (A–TiO2 and Z–TiO2) efficiency was compared to that with the TiO2, which demonstrated their adsorption and synergistic effect for the removal of chemical oxygen demand (COD) and color from the wastewater. At an optimal load of 4 g, the photocatalytic degradation activity (Z–TiO2 > A–TiO2 > TiO2) was found favorably by the second-order kinetic model. Consequently, the Langmuir adsorption isotherms favored the nanocomposites (Z–TiO2 > A–TiO2), whereas that of the TiO2 fitted very well on the Freundlich isotherm approach. Z–TiO2 evidently exhibited a high photocatalytic efficacy of decomposition over 80% of BPB (COD) at reaction rate constant (k) and coefficient of determination (R2) values of 5.63 × 10−4 min−1 and 0.989, respectively.
Water decontamination still remains a major challenge to some developing countries not having centralized wastewater systems. Therefore, this study presents the optimization of photocatalytic ...degradation of Basic Blue 41 dye in an aqueous medium by an activated carbon (AC)-TiO2 photocatalyst under UV irradiation. The mesoporous AC-TiO2 synthesized by a sonication method was characterized by X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy for crystal phase identification and molecular bond structures, respectively. The efficiency of the AC-TiO2 was evaluated as a function of three input variables viz. catalyst load (2–4 g), reaction time (15–45 min) and pH (6–9) by using Box-Behnken design (BBD) adapted from response surface methodology. Using color and turbidity removal as responses, a 17 run experiment matrix was generated by the BBD to investigate the interaction effects of the three aforementioned input factors. From the results, a reduced quadratic model was generated, which showed good predictability of results agreeable to the experimental data. The analysis of variance (ANOVA), signposted the selected models for color and turbidity, was highly significant (p < 0.05) with coefficients of determination (R2) values of 0.972 and 0.988, respectively. The catalyst load was found as the most significant factor with a high antagonistic impact on the process, whereas the interactive effect of reaction time and pH affected the process positively. At optimal conditions of catalyst load (2.6 g), reaction time (45 min), and pH (6); the desirability of 96% was obtained by a numerical optimization approach representing turbidity removal of 93% and color of 96%.
The role of β‐CoOOH crystallographic orientations in catalytic activity for the oxygen evolution reaction (OER) remains elusive. We combine correlative electron backscatter diffraction/scanning ...electrochemical cell microscopy with X‐ray photoelectron spectroscopy, transmission electron microscopy, and atom probe tomography to establish the structure–activity relationships of various faceted β‐CoOOH formed on a Co microelectrode under OER conditions. We reveal that ≈6 nm β‐CoOOH(01
1‾
${\bar{1}}$
0), grown on
1‾21‾
${\bar{1}2\bar{1}}$
0‐oriented Co, exhibits higher OER activity than ≈3 nm β‐CoOOH(10
1‾
${\bar{1}}$
3) or ≈6 nm β‐CoOOH(0006) formed on 02
2‾1
${\bar{2}1}$
‐ and 0001‐oriented Co, respectively. This arises from higher amounts of incorporated hydroxyl ions and more easily reducible CoIII−O sites present in β‐CoOOH(01
1‾
${\bar{1}}$
0) than those in the latter two oxyhydroxide facets. Our correlative multimodal approach shows great promise in linking local activity with atomic‐scale details of structure, thickness and composition of active species, which opens opportunities to design pre‐catalysts with preferred defects that promote the formation of the most active OER species.
Our correlative multimodal approach can link local activity with atomic‐scale details of structure, morphology and composition of surface species formed during the oxygen evolution reaction (OER). We found that a 6 nm β‐CoOOH(01
1‾
${\bar{1}}$
0) layer, grown on
1‾21‾
${\bar{1}2\bar{1}}$
0‐oriented Co, contains more hydroxyl ions and easily reducible CoIII−O sites, exhibiting a higher OER activity than 3 nm thick β‐CoOOH(10
1‾
${\bar{1}}$
3) formed on 02
2‾1
${\bar{2}1}$
‐oriented Co.
Purpose
Users of smallholder farmer microfinance are able to make enough returns to repay credits advanced to them. However, they are in dire need of financial capital such that they are ...inconsiderate of farmer- and credit-specific characteristics when participating in a microfinance programme. This study analyses perceptions of stakeholders regarding select farmer and credit characteristics within the microfinance industry. The study identifies and analyses the factors that influence participation in a microfinance programme by farmers using the logistic regression model. The purpose of this paper is to widen the knowledge base of rural agricultural finance, including factors that influence participation in microfinance intervention(s) thereof.
Design/methodology/approach
A total of 104 participants and 120 non-participant farmers in microfinance programmes were interviewed using a semi-structured questionnaire by applying the multistage sampling technique. The paper applied the logistic regression model in which farmer- and credit-specific characteristics were used to estimate the probabilities of participation.
Findings
The logistic regression results showed that distance, interest rate, experience, membership of farmer-based organisation, number of dependants, household, gender and age were statistically significant farmer- and credit-specific characteristics that influence participation in microfinance programmes. Interest rate and distance exact negative significance influence on participation, whereas membership of farmer-based organisations, experience, gender, household head and age influence participation positively. Reduction in the interest rate and expansion of microfinance to very remote areas rather than locations in urban areas are crucial in terms of improving participation.
Research limitations/implications
The paper used data from only farmers so there is a limit to which the results can be generalised for all microfinance users. It may be relevant to undertake a study that considers non-farm enterprises.
Practical implications
This paper brings to light the need to develop well-structured microfinance facilities that meet the specific needs of the rural poor in transitioning economies while taking into consideration critical factors affecting participation before the establishment of such programmes.
Originality/value
This paper provides empirical evidence to show that farmer- and credit-specific characteristics are essential to ensure participation and success of microfinance programmes thereof.
This study examined the application of an electromagnetic field to anaerobic digestion by using an electromagnetic system (ES), a microbial electrolysis cell (MEC), and a control with no external ...force. The experimental work was performed by carrying out biochemical methane potential (BMP) tests using 1 L biodigesters. The bioelectrochemical digesters were supplied with 0.4 V for 30 days at 40 °C. The electromagnetic field of the ES was generated by coiling copper wire to form a solenoid in the BMP system, whereas the MEC consisted of zinc and copper electrodes inside the BMP system. The best performing system was the MEC, with a yield of 292.6 mL CH4/g chemical oxygen demand removed (CODremoved), methane content of 86%, a maximum current density of 23.3 mA/m2, a coulombic efficiency of 110.4%, and an electrical conductivity of 180 µS/cm. Above 75% removal of total suspended solids (TSS), total organic carbon (TOC), phosphate, and ammonia nitrogen (NH3-N) was also recorded. However, a longer exposure (>8 days) to higher magnetic intensity (6.24 mT) on the ES reduced its overall performance. In terms of energy, the MEC produced the greatest annual energy profit (327.0 ZAR/kWh or 23.36 USD/kWh). The application of an electromagnetic field in anaerobic digestion, especially a MEC, has the potential to maximize the methane production and the degradability of the wastewater organic content.
In this study, three coagulants (ferromagnetite (F), alum (A), and eggshells (E)) and their hybrids (FA, FE, and FEA) were investigated as possible cost-effective coagulants for the treatment of ...industrial wastewater. Scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDX) was used to characterize the morphological and elemental compositions of the coagulants. The effects of coagulant dosage (10-60 mg/L) and settling time were investigated for the removal of turbidity, color, and total suspended solids. A jar tester (JTL6) operating at conditions of 150 rpm for 2 min (rapid mixing) and 30 rpm for 15 min (slow mixing) was employed. Results from the characterized supernatant showed about 80% removal of the contaminants. The prospects of F were proven to be the most effective as compared to the binary (FA > FE) and the ternary hybridized (FEA) coagulants. At an optimum dosage and settling time of 20 mg/L and 30 min, respectively, the treatability performance of F was clearly proven to be viable for wastewater treatment.
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