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The ventilated improved pit (VIP) latrine offers a promising route to safely managed sanitation to many households in developing countries. However, some technical guidelines must be followed in order to realise the technology's advantage of odour and fly nuisance control. This study sought to audit private VIP latrines in selected regions of Ghana to assess their compliance to conventional technical guidelines and to understand the major factors that influence the latrine designs. An inspection checklist was developed to assess 296 private VIP latrines in the Central, Ashanti and Northern Regions of Ghana while semi-structured interviews were conducted among the latrine owners to enquire the factors that influenced the designs of their latrines. The results show that provision of a window in the superstructure (86 %), and the avoidance of an insect screen in the window(s) (77 %) were the most complied guidelines. The use of 150 mm diameter vent pipe was the least satisfied guideline (5 %). On the average, a latrine satisfied about half (3.6) of the technical guidelines that were assessed. The decision or advice of local artisans is the most influential factor in the design of the latrines. Cost was the least mentioned factor cited by the latrine owners. There is the need to establish information desks at the various Metropolitan, Municipal and District Assemblies (MMDAs) to guide prospective owners on the proper design and construction of the VIP latrine. In addition, toilet construction should be incorporated in the curriculum for the basic training of building and construction students in Technical and Vocational Education and Training (TVET) institutions in Ghana. Further research is required to ascertain the basis of the decisions of local artisans and the potential impact of the use of accessories that are ‘borrowed’ from the WC toilet on odour and fly control in the latrine.

Substituting biogas for Liquefied Petroleum Gas (LPG) in households is a long-awaited sustainable solution for the increasing cost of energy and large amounts of household human-generated waste. Nevertheless, a study of the characteristics of feedstocks is essential to maximise their energy potential. Consequently, this study examined the physico-chemical properties of Human Excreta (HE), Food Leftovers (FLO), Kitchen Residue (KR) and Cow Dung (CD) of Ghanaian origin adhering to recommended standards. Results for volatile to total solid ratios (VS/TS) were 0.81 ± 0.001, 0.97 ± 0.001,0.89 ± 0.001 and 0.85 ± 0.001 for HE, FLO, KR and CD, respectively. The results showed that all feedstocks had high biodegradable content, making them desirable for biogas production. The carbon-to-nitrogen (C/N) ratios determined from the elemental compositions were 8.29 ± 0.09, 22.14 ± 0.26, 23.34 ± 0.25 and 26.19 ± 0.47 for HE, FLO, KR and CD, respectively. Although the C/N ratios for FLO, KR and CD were within the optimal range, that of HE was significantly low. With a mean alkalinity of 1219.67 ± 1.53, 630.00 ± 0.58, 590.00 ± 2.08 and 15,730.00 ± 6.00 mg CaCO3 eq./L for HE, FLO, KR and CD, it was observed that only CD has the optimal alkalinity value for anaerobic digestion. This brings into perspective the need for co-digestion and the choice of potential co-substrates for household biogas production.

Study region: Ghana, West Africa. Study focus: NASA's Prediction of Worldwide Energy Resource (NASA POWER) satellite-based reanalysis products are used for estimating the aridity index (AI) in Ghana, West Africa. The NASA estimates are compared and bias-corrected with temperature-based potential evapotranspiration estimates and rainfall data from 22 synoptic climate stations. The cumulative distribution function (CDF) matching technique was used for bias correction New Hydrological Insights for the region: The results indicated a previous 36% over-estimation of arid conditions in dryland climates and an under-estimation of wetland climate regions by the NASA POWER data compared with the station-based estimation. Post bias-correction, the satellite-based estimates showed substantial improvements, as evidenced by a correlation coefficient of R2 = 0.87. The rectified data suggests that with accurate interpretations and calibrations, satellite-based metrics can play a pivotal role in advancing hydrological studies and water resource management in West Africa Sub-region. This insight underscores the potential of satellite data in augmenting regional hydrological research, establishing a foundation for similar studies in analogous global environments.

Abstract 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.

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

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.

ABSTRACTFood waste can be converted to a useful product such as biochar as a way of recycling waste to retain nutrients in the soil, which in turn contributes to carbon sequestration and offset some greenhouse gas emissions in the struggle to achieve carbon neutrality. Mixed food waste-derived biochars (FWB1–300°C, FWB2–450°C and FWB3–600°C) were pyrolysed at 300°C, 450°C and 600°C, respectively, using an electric kiln. Tests for physiochemical parameters and germination tests were performed. It was realized that at 300°C biochars produced had high nitrogen, organic matter, bulk density, biochar yield, and longer root lengths. The results indicate that municipal food waste biochars produced at three temperatures were suitable for use as fertilizer. However, biochar produced at a moderately lower temperature is favourable for agriculture purposes, FWB1–300°C and FWB2–450°C obtained moderate pH and ash levels and so are less toxic to the growth of plants.

Purpose The study assessed the quality of compost produced by the Black Soldier Fly Larvae (BSFL) in terms of the compost nutrient level, microbial activities, and the bioaccumulation of possible heavy metals in the organic solid waste.Method The study used the pre-experimental study design, one-group pretest-posttest to obtain the data. Five experimental units were used for the study, which include the daily feeding rate for the five different groups of larvae. The experiments were replicated three times. The nutrient level, heavy metal content and presence of microbes were analyzed before and after the decomposition process.Results The study discovered that the Nitrogen, Phosphorus and Potassium (NPK)content increased in the compost produced. Cross-contamination of Total Coliform from feed to the prepupae were significant while regrowth of Total Coliform in compost were insignificant. After the composting process most heavy metals like Fe had insignificantly increased in the compost .Conclusion It can be concluded that larval composting enhance the regrowth of pathogens since the process is entirely mesophilic. Bioaccumulation of most heavy metals was minimum, increasing the level of these heavy metals in the compost. The nutrients were extremely high in the compost to the extent that can cause phyto-toxicity. Post-treatment of the compost is needed to make BSFL compost viable for the market.

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.

Abstract 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 $$0.5^\circ \times 0.5^\circ$$ 0 . 5 ∘ × 0 . 5 ∘ 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.

Abstract 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.

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).

The search for alternative solutions for sustainable management of faecal sludge in the area of dewatering with biocoagulants/bioflocculants remains unfulfilled. Some available and accessible indigenous plants in the northern part of Ghana have been characterised and subsequently evaluated in their suitability for use as biocoagulant/bioflocculants. The Yila (Crossopteryx febrifuga) and the Voulo (Grewia mollis) plants were the indigenous plants used in this study. Three applications from the Yila wooden stem, the Yila bark, and the Voulo at different treatment concentrations with faecal sludge were monitored. The Yila wooden stem gave a potential of pollutant removal up to about 83.99%, 93.79%, and 91.54% for Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), and turbidity, respectively. Application of the Yila bark gave a respective removal efficiency of up to about 77.39%, 82.02%, and 54.60% for COD, TSS, and turbidity. The efficiency of the Voulo plant obtained for COD, TSS, and turbidity was up to about 80.43%, 86.83%, and 72.55%, respectively. No cyanogenic or toxic compounds were identified in the characterised raw materials used for this study. The study has revealed the potential of producing biocoagulants that can perform as effectively as synthetic/chemical coagulants using locally natural raw materials but the use of it at large scale will only be applicable for batch or semi-batch systems. Some interesting constituents identified in the plants under consideration, such as trialkyl bismuthine and furan derivative, can open up opportunities to elucidate the potential applications of these identified plants in the areas of pharmaceuticals, cosmetics, glass and ceramics, rubber production, and other applicable medicinal advantageous areas.

This study evaluates the applicability of dry faecal sludge activated carbon (DFSAC) as a wastewater pollutant removal technology by employing both laboratory- and large-scale setups. The setups were monitored using effluent from the Mudor wastewater treatment plant in Accra. The DFSAC was produced from primary sludge obtained from a primary treatment to treat approximately 1000 liters of effluent water per hour to meet the needs of backwashing, cleaning, irrigation, and flushing purposes. The laboratory-scale experiment was monitored for a period of two weeks, while the large-scale experiment was monitored for a period of 16 weeks. Physicochemical, microbial, and metal characteristics were analyzed for the polished effluent. The results obtained from the lab scale showed high removal efficiencies of the wastewater pollutants for the first and second weeks of treatments, respectively, as follows: colour (99.47%, 69.06%), turbidity (99.59%, 42.59%), COD (96.58%, 43.49%), BOD (99.26%, 77.42%), TSS (100%, 62.296%), TDS (92.92, 32.90), ammonia (98.41%, 50.83%), and EC (73.60%, 19.94%). The P value obtained indicated a highly significant difference between the influent and effluents of both weeks. The large-scale application of the DFSAC yielded a percentage reduction of 99.36%, 99.37%, 99.52%, 79.63%, 100%, 48.85%, 90.08%, and 46.72% for colour, turbidity, COD, BOD, TSS, TDS, ammonia, and EC, respectively. The DFSAC showed high removal potential for heavy metals and microbial contaminants over the study period. Pollutant removal in wastewater with DFSAC proved a promising intervention by significantly reducing pollutants in wastewater effluent as a tertiary treatment. The removal efficiencies are indications that physisorption and chemisorption play an important role in the adsorption of pollutants onto the DFSAC. The study has shown that faecal sludge can be used as activated carbon for remediation of wastewater pollutants, especially in treatment facilities, which do not meet EPA effluent discharge guidelines while ensuring a close resource utilization loop.

Precipitation of phosphorus (P) as a struvite product from wastewater and local magnesium (Mg) sources is considered as a high economical prudent venture, as it has shown to bring down the cost of producing the product. However, there is a significant concentration of calcium (Ca) in these Mg and most wastewater sources. The presence of Ca in wastewater and Mg sources during struvite precipitation has been shown to negatively affect the quality of the struvite produced. The low struvite quality greatly impedes its use as a fertiliser given the economic value of the product as an alternative P fertiliser. This review paper provides an understanding of how the presence of Ca affects the purity, crystal size, and morphology of the struvite. Different methods that have been used to mitigate the effect of Ca on struvite quality have been reviewed. The factors that affect the recovery of P and the percentage recoveries of P by different Mg sources have also been reviewed. This paper serves as a basis for further research where the possibility of removing Ca from wastewater and Mg sources is explored. When Ca is removed before struvite precipitation is carried out, the quality of the product will be greatly improved. HIGHLIGHTS Trend analysis of impact of Ca on struvite quality has been done.; All methods for the mitigation of the negative impact of Ca have been reviewed.; Nutrient removal efficiencies of Mg sources have been compared.; Molar ratios that affect struvite quality have been identified.; Research gap for improving struvite quality has been identified.;

Abstract 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.

The recovery of food waste fraction of municipal solid waste and value addition has not received attention despite the high composition in the solid waste stream. This paper presents a study on the drying of food waste, the safety and nutritional quality of the dried food waste as an alternative feed ingredient to maize in the poultry feed production. Food waste was dried at different temperatures using solar, a halogen oven and conventional oven dryers. The dried food waste samples were analyzed for microbial load, aflatoxins, heavy metals, and nutritional quality. The drying of the food waste to less than 10% moisture content was between 22 h (2–3 days) for the solar dryers and 4 -10 h for the halogen and conventional oven dryers. For the different dryers, the macronutrients (protein, carbohydrate, and lipid) of the dried food waste were lower than the fresh food waste, but the nutritional quality meets the requirement for poultry feed quality. Toxicity of the cadmium, arsenic, aflatoxin and microbial levels in the dried food waste was lower compared to that of the fresh food waste and within the poultry feed guideline values. The oven drying at temperature 155 °C retained the macronutrients and reduced the toxins in the dried food waste, and therefore was the optimum for dehydration and converting food waste into poultry feed.

Carbon Capture, Utilization and Storage (CCUS) is a pragmatic technology that could reduce anthropogenic CO2 and halt climate change. CO2 injectivity is affected by several physicochemical interactions around the injection area of the wellbore which are temperature-dependant. There is a thermal disequilibrium between the injected CO2 and the reservoir rock at the wellbore injection area which has not been thoroughly investigated. A pore-scale model was developed to predict the distance travelled by the injected fluid into the formation before thermal equilibrium is established. In the Snøhvit field where the wellhead injection temperature is 4 °C, it was found that the injected CO2 may attain supercritical state at bottomhole conditions, although a minimum temperature difference of about 40 °C may exist between the bottomhole fluid and the reservoir rock. Thermal equilibrium around the injection area was dependant on the wellhead injection temperature, the injection flow rate and reservoir shaliness.

The healthcare waste management in developing countries has shortfalls compared with international best practices. The main purpose of this study was to assess the generation rate, composition and practices of healthcare waste management (HWM) in Kumasi, Ghana. Healthcare waste samples were collected from four hospitals and three healthcare centres for waste generation, composition and bulk density analyses. The average waste generation rates of the hospitals ranged from 0.76 to 2.92 kg/bed-day and that of the community health centres ranged from 0.012 to 0.08 kg/patient-day. The compositions of the general and hazardous healthcare wastes were 50.35% and 49.65% respectively. The hazardous healthcare waste far exceeded the World Health Organization threshold of within 10 – 25% as a result of inadequate segregation. The facilities had no specific HWM framework and did not comply with best practices. The lack of National regulatory framework for HWM may compromise the prevention of disease transmission.

The design and performance analysis of landfill systems require information on the characteristics of landfill waste as well as the operational activities at the landfill site. There is however limited information on the characteristics of landfill waste in Ghana. This study examined the waste characteristics and the operational management at the Oti landfill in Kumasi, Ghana. For the waste characterization, samples from different areas and depths of the landfill, representing different ages of deposition were used. Truck time studies, as well as spreading and compaction of offloaded waste at the landfill was also studied. A logarithmic relationship was found between average unit weight and age of deposition. The high content of plastics (up to 58%) in the waste stream calls for recycling to prolong the life span of the landfill. The findings on the waste composition also has implications for landfill mining in the future. The unit weight of the compacted waste ranged from 4.28 kN m−3 to 16.64 kN m−3 depending on the depth and age of waste deposition. The average compacted unit weight of 11.87 kN m−3 was higher than the estimated 8.83 kN m−3 used for the design of the landfill. The total volume of the void space available at the landfill will therefore be able to receive waste more than the estimated 15-year period. The compaction studies revealed that the compaction of waste was adequate, and that the number of compactor passes was directly proportional to the amount of waste offloaded. Keywords: Landfill, Municipal solid waste, Waste composition, Unit weight, Landfill design, Landfill compaction

This paper reviews the effect of applying optimization methods on the collection process of solid waste, with particular interest in mathematical programming and geographic information system approaches in developing countries. Mathematical programming approaches maximize or minimize an objective function for improvement in procedure, to ensure operational efficiency and also serve as decision support tools. They however provide partial solutions when implemented in reality and cannot fully handle road network constraints. Geographic information system approaches allow processing of additional considerations, often ignored in other methods, such as the street network modeling. Incorporating environmental pollution consideration is very challenging in this approach, the vehicle routing problem solver encountering limits for large data. For enhanced efficiency of the vehicle routing systems, studies should further focus on incorporating all network constraints, environmental pollution considerations, and impact of land use changes on routing.