Anaerobic co-digestion of human excreta, food leftovers and kitchen residue: 1 ternary mixture design, synergistic effects and RSM approach.

Anaerobic digestion of multiple substrates can generate more biogas while remaining stable, if positive synergistic effects are achieved. The type of co-digested substrates and the mixing ratio used, are the most important variables as each substrate has unique set of characteristics. Optimizing the volume ratios by testing various substrate mixing ratios is a popular method for determining the best-performing ratio of substrate mixture. The ternary mixture design has reportedly been found to quicken the process of testing different mixing ratios with high accuracy without running several experiments. Therefore, a ternary mixture design and a response surface approach are used in this work to ascertain the relationship between substrate mix and responses (biogas yield, methane yield, and synergy). The findings of the experiment revealed that R9 comprising 78.8 % human excreta, 11.8 % food leftovers and 9.4 % kitchen residue, had the highest methane production of 764.79 mLCH4/gVS and a synergistic index of 3.26. Additionally, the 3D response surface plots from the response surface model showed important and shared interactions between Human Excreta, (HE), Food Leftovers (FLO), and Kitchen Residue (KR). HE and KR had a similar positive synergistic effect on biogas yield, methane yield, and synergy, which was not the case for FLO. The response surface plots showed that the predicted responses (methane yield, biogas yield and synergy) increased with increasing HE and KR fractions and decreased with increasing FLO fractions in the substrate mixtures.

Self-supply groundwater in five communities: Moshie Zongo, Aboabo, Kotei, Ayeduase and Apemso in Kumasi Metropolis, Ghana.

Self-supply water has been acknowledged as a viable alternative to meeting the water needs of inhabitants. This study was designed to determine the main issues that influence self-supply water coverage in five (5) communities in the Kumasi Metropolis. The research employed a well-structured questionnaires and a total of 369 households were surveyed. The Statistical Package for Social Sciences (SPSS) version 26 and Microsoft Excel (2016) tools were used to analyse the data. The outcomes of the research show that a greater number of the respondents (77 %) did not have connections to the Ghana Water Company Limited (GWCL) distribution system. Approximately, 69 % of respondents had access to alternative water sources with mechanized boreholes forming the majority (32 %). However, a greater number of the respondents (64 %) did not disinfect their water to make it potable. The most favourable drinking water source for a greater number of the residents (51 %) was sachet water. The study showed there was a significant association between respondents' type or source of water with religion (p < 0.000), household size (p < 0.000), duration of stay (p = 0.026) and number of dependents (p = 0.006). However, there was no association between type or source of water with educational level (p = 0.130), occupation (p = 0.310), income level (p = 0.139) and type of home (p = 0.102). This study revealed that self-supply is contributing to the water needs of some residents in Kumasi and could contribute to the country's accomplishment of SDG 6.1 if residents ensure that it is safely managed. To broaden the scope of the study and the impact of self-supply groundwater, additional studies should be conducted in other communities, as well as the extent of other beneficiaries who have access to self-supply facilities other than the owners.

Understanding fluoride adsorption from groundwater by alumina modified with alum using PHREEQC surface complexation model.

Fluoride is recognized as a vital ion for human and animal growth because of the critical role it plays in preventing skeletal and dental problems. However, when it is ingested at a higher concentration it can cause demineralization of teeth and bones resulting in fluorosis, therefore, the production of high-adsorptive capacity material which is also cost-effective is necessary for the treatment of fluorides. In this study, aluminium foil is valorised into alumina nanoparticles. The as-prepared alumina was modified with alum in two different ratios of 1:0.5 and 1:1 (alumina to alum w/w%) and later used as adsorbents for the removal of fluoride from groundwater. The adsorbents were characterized by Fourier transform infrared spectroscopy, point of zero charge and X-ray diffraction. Different factors that influence the removal efficiency of fluorides such as pH, initial concentrations, contact time and adsorbent dosage were studied and optimized using a simulated fluoride solution. The optimum conditions obtained were used to test real groundwater. The static experiment conditions were used to calibrate a PHREEQC geochemical model which was later used to simulate the fluoride sorption onto the modified alumina at different conditions. PHREEQC was also coupled with parameter estimation software to determine equilibrium constants for the surface reactions between the fluoride species and the adsorbent in a way that the simulations accurately reflect the outcomes of laboratory experiments. Isotherm studies were carried out on the adsorbents. Both Langmuir and Freundlich's non-linear models fitted well for the equilibrium data. However, with a higher coefficient of regression and low chi-square test values, the adsorption process was more of chemisorption on a monolayer surface. Kinetic studies were also carried out by using the non-linear equations from the pseudo-first-order and pseudo-second-order models. The pseudo-second-order model fitted well for the equilibrium data. The mechanism for the fluoride ion adsorption was also studied by the intraparticle (IP) diffusion model and was found that IP was not the rate-determining factor, and therefore the most plausible mechanism for the sorption process was ion exchange or attraction of fluoride ions to the sorbent surface. The findings obtained from this research show that readily available aluminium waste could be valorised into a useful product that could be employed in the removal of fluoride from water samples, including groundwater, that may contain too much fluoride and pose a risk to the general public's health.

Assessment of the Knowledge, Prevalence, and Control Strategies of Malaria Among Households in Sunyani Municipality, Bono Region, Ghana.

Background: Malaria remains a global public health concern for centuries. The study assessed the knowledge, prevalence and control strategies of malaria among households in the Sunyani Municipality, Bono Region, Ghana. Method: A simple random sampling method was used to administer semi-structured questionnaires to the respondents (n = 422). STATA version 14.0 was used to analyse the data and the results were presented in charts, graphs, and tables. Result: The study shows that the knowledge level of malaria, its vector of transmission and mosquitoes breeding sites among the respondents was quite high. Among the respondents, 43% reported to have been infected by malaria once in a year and 94% indicated that, their relatives have been infected with malaria parasites previously. Also, majority, 65% of the respondents selected environmental management and sanitation (EMS), followed by settlement (building houses) away from wetlands, 20.0% as alternative vector control methods to be employed to supplement the core vector control methods in the Municipality. Further, majority, 69% of the respondents indicated that enforcement of environmental sanitation bye-laws will compel residents to clean their environment, and this is likely to eliminate most mosquito breeding sites, whiles 46% called on Government to support, and employ more Environmental Health Officers and Sanitary Labourers, and adequately resource them to work effectively. Conclusion: Health authorities in the Sunyani Municipality must intensified education on malaria at all levels with the aim to influence the attitudes of households towards its prevention and control. Central and Local Government must employ more Environmental Health Officers, and empower and adequately resourced them to strictly enforce the environmental sanitation bye-laws. Malaria control authorities in the study area must consider employing environmental management and sanitation (EMS) and application of larvicides for mosquito larval control as alternative/supplementary malaria prevention and control methods to compliments the current core vector control methods.

Environmental Management and Sanitation as a Malaria Vector Control Strategy: A Qualitative Cross-Sectional Study Among Stakeholders, Sunyani Municipality, Ghana.

Background: For centuries malaria infection remains a public health burden globally as well as in the Sunyani Municipality. This exploratory qualitative study aimed to assess the prospects of environmental management and sanitation (EMS) as a malaria vector control strategy among key stakeholders involved in the prevention and control of malaria in Sunyani Municipality, Ghana. Method: We used an exploratory qualitative study and a designed focus group discussion (FGD) guide (with specific research questions) to solicit opinions and/or views among Malaria Control Focal Persons, Environmental Health Officers (Health Inspectors), and Honourable Assembly Members. Data were collected between December 2019 and February 2020. The responses were analyzed according to the specific research questions. Result: Findings from this study shows that high government support and/or political will by investing in environmental sanitation infrastructure, creating the enabling environment for strict enforcement of environmental sanitation bye-laws by Environmental Health Officers/Health Inspectors, effective and efficient collaboration among key stakeholders and organization of communal labor activities is likely to help reduce the majority of the mosquito breeding sites. Conclusion: The prospects of environmental management and sanitation (EMS) as a vector control strategy, look promisingly very high, pertinent, and workable and a likelihood game changer of winning the fight against malaria due to the residual transmission that is happening outdoors. However, EMS can be employed as a supplementary method to the current core vector control methods if the following conditions and bottlenecks are addressed and in place: (a) Effective collaboration among key stakeholders at all levels; (b) Adequate allocation of funds to the Environmental Health and Sanitation Department; (c) Enactment of robust educational campaigns across all educational levels and via different media; (d) Recognition, empowerment, and adequate resourcing of Environmental Health Officers; (e) Adherence to the building regulations to prevent encroachment of natural wetlands; (f) Revision of fees/fines and prosecution of sanitary offenders; (g) Enactment of an Environmental Sanitation Day (ESD), and establishment of the Environmental Health and Sanitation Fund (EHSF).

Assessment of solar radiation resource from the NASA-POWER reanalysis products for tropical climates in Ghana towards clean energy application.

In order to expand the output of solar power systems for efficient integration into the national grid, solar energy resource assessment at site is required. A major impediment however, is the widespread scarcity of radiometric measurements, which can be augmented by satellite observation. This paper assessed the suitability of satellite-based solar radiation resource retrieved from the NASA-POWER archives at [Formula: see text] spatial resolution over Ghana-West Africa, to develop a long-term source reference. The assessment is based on the criteria of comparison with estimations from sunshine duration measurement for 22 synoptic stations. Overall, the satellite-based data compared well with ground-based estimations by r = 0.6-0.94 ± 0.1. Spatiotemporally, the agreement is strongest over the northern half Savannah-type climate during March-May, and weakest over the southern half Forest-type climate during June-August. The assessment provides empirical framework to support solar energy utilization in the sub-region.

Indoor air quality improvement and purification by atmospheric pressure Non-Thermal Plasma (NTP).

Non-thermal plasma (NTP) is a promising technology for the improvement of indoor air quality (IAQ) by removing volatile organic compounds (VOCs) through advanced oxidation process (AOP). In this paper, authors developed a laboratory scale dielectric barrier discharge (DBD) reactor which generates atmospheric NTP to study the removal of low-concentration formaldehyde (HCHO), a typical indoor air VOC in the built environment associated with cancer and leukemia, under different processing conditions. Strong ionization NTP was generated between the DBD electrodes by a pulse power zero-voltage switching flyback transformer (ZVS-FBT), which caused ionization of air molecules leading to active species formation to convert HCHO into carbon dioxide (CO2) and water vapor (H2O). The impact of key electrical and physical processing parameters i.e. discharge power (P), initial concentration (Cin), flow rate (F), and relative humidity (RH) which affect the formaldehyde removal efficiency (ɳ) were studied to determine optimum conditions. Results show that, the correlation coefficient (R2) of removal efficiency dependence on the processing parameters follow the order R2 (F) = 0.99 > R2 (RH) = 0.96, > R2 (Cin) = 0.94 > R2 (P) = 0.93. The removal efficiency reached 99% under the optimum conditions of P = 0.6 W, Cin = 0.1 ppm, F = 0.2 m3/h, and RH = 65% with no secondary pollution. The study provided a theoretical and experimental basis for the application of DBD plasma for air purification in the built environment.

Inhibition of ammonia and hydrogen sulphide as faecal sludge odour control in dry sanitation toilet facilities using plant waste materials.

On-site dry sanitation facilities, although cheaper than wet sanitation systems, suffer from high malodour and insect nuisance as well as poor aesthetics. The high odour deters users from utilizing dry sanitation toilets as an improved facility leading to over 20% open defecation in Sub-Saharan Africa. To address this malodour concern, this study first assessed odour levels, using hydrogen sulphide (H2S) and ammonia (NH3) as indicators, on two dry sanitation facilities named T1 and T2. The potential of using biomass (sawdust, rice husk, moringa leaves, neem seeds), ash (coconut husk, cocoa husk) or biochar (sawdust, rice husk, bamboo) as biocovers to remove or suppress odour from fresh faecal sludge (FS) over a 12-day period was investigated. Results showed that the odour levels for H2S in both T1 (3.17 ppm) and T2 (0.22 ppm) were above the threshold limit of 0.05 ppm, for unpleasantness in humans and vice versa for NH3 odour levels (T1 = 6.88 ppm; T2 = 3.16 ppm; threshold limit = 30 ppm limit). The biomasses exhibited low pH (acidic = 5-7) whereas the biochars and ashes had higher pHs (basic = 8-13). Basic biocovers were more effective at H2S emission reduction (80.9% to 96.2%) than acidic biocovers. The effect of pH on suppression of NH3 was determined to be statistically insignificant at 95% confidence limit. In terms of H2S and NH3 removal, sawdust biochar was the most effective biocover with odour abatement values of 96.2% and 74.7%, respectively. The results suggest that biochar produced from locally available waste plant-based materials, like sawdust, can serve as a cost-effective and sustainable way to effectively combat odour-related issues associated with dry sanitation facilities to help stop open defecation.

Market waste composition analysis and resource recovery potential in Kumasi, Ghana.

Municipal solid waste constitutes significant quantities of waste generated in markets. Markets produce substantial quantities of fruit and vegetable waste, a source of nuisance in landfills. In Ghana, market waste (MW) appears to be unexplored and has limited data available. The need for MW valorization in the face of a circular economy requires reliable knowledge of MW properties. The study determined the waste compositions of selected major markets from two different classes of settlement in Kumasi and the seasonal effect on the compositions. The chemical properties of organics were determined via proximate and ultimate analyses and the theoretical biomethane potential, with the Buswell equation. From the results, MW composition in the wet season is 59.6% organic, 11.4% plastics, 8.3% paper, 5.3% textiles, 4.7% inert, 4.1% miscellaneous, 2.1% metal, 1.8% glass and 2.8% leather. The dry season values are 45.8% organic, 14.6% plastics, 12.7% paper, 7.3% textiles, 6.4% inert, 4.3% miscellaneous, 2.3% metal, 2.6% glass and 3.9% leather. An ANOVA indicates significant differences between the two seasons and some waste components; organics, plastics, paper and cardboard, leather, and inert. The high calorific values recorded ranged from 14.8 MJ kg-1 to 16.6 MJ kg-1. The biogas potential and biomethane content ranged from 775.3 l/kgVS to 828.9 L/kgVS and 50% to 57% respectively.Implications: Market waste (MW) in Ghana appears to be an unchartered area and there is limited data on market generation and composition. The need for MW valorization requires reliable knowledge on MW properties. This study explores MW characteristics of six major market from two different classes of settlements in a developing country. Study findings suggest that the quantities of market organics are higher than household waste. Again, MW composition can be influenced by season and geographical location. Furthermore, the study establishes the potential of MW in considerable quantities of biogas and methane generation, in comparison with household waste.

Degradation and accumulation rates of fresh human excreta during vermicomposting by Eisenia fetida and Eudrilus eugeniae.

This study was carried out to assess the degradation and accumulation rates of fresh human excreta and how addition of anal cleansing materials affect performance during vermicomposting by Eisenia fetida and Eudrilus eugeniae. Vermicomposting setups consisting of two transparent containers (length 0.27 m, breadth 0.17 m and depth 0.12 m) stacked on top of each other were installed and operated under laboratory conditions. Earthworms, Eisenia fetida and Eudrilus eugeniae, were obtained from Green Cycle Technologies Limited in Accra, Ghana and the species verified and cultured before use. Fresh human excreta for feeding the experimental setups was collected from an Enviro-loo public toilet and 13 g applied to the setups daily. Similar setups were fed with 0.3 g of anal cleansing material in addition to the fresh excreta. A setup without any earthworms (NW) was set up as a control. Physicochemical characteristics of vermicompost accumulating in the setups were determined weekly for 28 days using standard laboratory procedures while the sludge accumulated in the various setups were weighed and recorded daily. One-way analysis of variance (ANOVA) and Post-hoc LSD tests were conducted to determine whether the differences in results between the two earthworm species and among setups with and without anal cleansing materials were statistically significant (p ≤ 0.05). The study showed 12.3% and 26.2% reduction in volatile solids in EE (Eudrilus eugeniae and excreta only) and EF (Eisenia fetida and excreta only) while ash content increased indicating good degradation. The percentage mass reductions recorded at the end of the fourth week were 67.5%, 58.8% and 40.5% in systems EE, EF and NW respectively, while reductions of 73.7% and 68.5% were realized in EEA (Eudrilus eugeniae with excreta and toilet paper) and EFA (Eisenia fetida with excreta and toilet paper) respectively. There was greater amount of sludge accumulated in systems without earthworms, 0.00020 m3 (59.5%) in NW, than in systems with earthworms where 0.00011 m3 (32.5%) and 0.00014 m3 (41.2%) were recorded for EE and EF respectively. The rate of accumulation in vermibeds EE and EF was relatively higher than in vermibeds with excreta and toilet paper (EEA and EFA). EEA and EFA recorded accumulation rates of 0.00009 m3 (26.3%) and 0.00011 m3 (31.5%) respectively. Complete removal of helminth eggs was not achieved in any of the treatment systems.

Microbial Groundwater Quality Status of Hand-Dug Wells and Boreholes in the Dodowa Area of Ghana.

To assess the suitability of water sources for drinking purposes, samples were taken from groundwater sources (boreholes and hand-dug wells) used for drinking water in the Dodowa area of Ghana. The samples were analyzed for the presence of fecal indicator bacteria (Escherichia coli) and viruses (Adenovirus and Rotavirus), using membrane filtration with plating and glass wool filtration with quantitative polymerase chain reaction (PCR), respectively. In addition, sanitary inspection of surroundings of the sources was conducted to identify their vulnerability to pollution. The presence of viruses was also assessed in water samples from the Dodowa River. More than 70% of the hand-dug wells were sited within 10 m of nearby sources of contamination. All sources contained E. coli bacteria, and their numbers in samples of water between dug wells and boreholes showed no significant difference (p = 0.48). Quantitative PCR results for Adenovirus indicated 27% and 55% were positive for the boreholes and hand-dug wells, respectively. Samples from all boreholes tested negative for the presence of Rotavirus while 27% of the dug wells were positive for Rotavirus. PCR tests of 20% of groundwater samples were inhibited. Based on these results we concluded that there is systemic microbial and fecal contamination of groundwater in the area. On-site sanitation facilities, e.g., pit latrines and unlined wastewater drains, are likely the most common sources of fecal contamination of groundwater in the area. Water abstracted from groundwater sources needs to be treated before use for consumption purposes. In addition, efforts should be made to delineate protected areas around groundwater abstraction points to minimize contamination from point sources of pollution.

The effect of increased private sector involvement in solid waste collection in five cities in Ghana.

Private sector involvement in solid waste management in developing countries has increased, but the effect is not always clear. This study assesses how it has been organized in five cities in Ghana, what has been its effect and what lessons for private sector development in developing countries can be drawn. Data were collected from 25 private companies and a sample of 1200 households. More than 60% of solid waste in Ghanaian cities is now collected by private enterprises. Sometimes, and increasingly, competitive bidding takes place, although sometimes no bidding is organized leading to rendering of this service and no contract being signed. Local governments and local solid waste companies have not changed to more customer-oriented delivery because of the slow pace of charging users and the resulting low rate of cost recovery. The participation of the population has been limited, which contributes to low cost recovery. However, a gradual better functioning of the system put in place is shown. We observed an increasing use of competitive bidding, signing of contracts and city-wide user charging.