Financing mechanism for solid waste management in Anambra, Nigeria: analyses of emerging challenges and implication for circular economy.

Waste management is a critical public service provided by municipalities around the world. It is often problematic, inefficient, and abysmally performed in developing countries. Among the problems associated with waste management in these global locations is the issue of finance. Finance is required for both capital investment and operational costs. Methods of waste management financing differ from place to place due to cultural, political, and socio-economic peculiarities. Understanding these conditionalities is necessary to be able to proffer sustainable solutions. Despite these facts, there is limited comprehensive and relevant academic literature on waste management financing mechanisms in developing countries both in the past and recent times. This work addresses a significant gap in the literature by studying the mechanism for waste management financing in developing countries using Anambra State, Nigeria, as a case study. The current study further investigated the associated challenges and opportunities and made critical discussions on the implications on the circular economy. User fees and subsidies from the government are the major financing sources. The absence of cost-revenue model analysis, economic and institutional volatility, the unwillingness of the service users to pay fees, and lack of transparency are major challenges to the financial sustainability of waste management in the studied context. The creation of incentives for behavioral changes, adoption of neo-liberal policies, and formal integration of informal waste pickers are factors that can minimize the cost of waste management services while promoting a circular economy.

Heavy metal contamination of soil, sediment and water due to galena mining in Ebonyi State Nigeria: Economic costs of pollution based on exposure health risks.

In this study, the effect of galena mining with respect to heavy metal pollution of groundwater, surface water, soil and sediments in Enyimagalagu and Mkpuma-Akpatakpa Communities in Ebonyi State, Nigeria, was investigated to estimate the health and economic burden. The heavy metals were measured using atomic absorption spectrometry (AAS). The water quality of the groundwater and surface water was determined using the water quality index (WQI). The potential health burden was estimated by determining carcinogenic and non-carcinogenic health risks via risk index (RI) and hazard index (HI), respectively. The potential economic burden was estimated using the value of statistical life (VSL) and cost of illness (COI). Obtained results revealed that the WQI of the groundwater and surface water ranged from 197 to 327 indicating very poor to unsuitable water for drinking. No non-carcinogenic risks were associated with exposure to the soil and sediment components of the environment. However, there were non-carcinogenic risks associated with the surface and groundwater, with the HIs ranging from 1.8 to 5.4. Based on the carcinogenic risk threshold of 10-6, there were carcinogenic risks across all the environmental media ranging from 8.4*10-5 - 2.1*10-3. The economic cost of heavy metal pollution ranged from 20.7 million USD (10.35 billion) to 543.3 million USD (271.6 billion) for the VSL, whereas it ranged from 0.141 million USD (70.8 million) to 3.72 million USD (1.86 billion) for the COI. These costs are quite huge and can be avoided via pollution abatement measures.

Legacy PAHs in effluent receiving river sediments near a large petroleum products depot in Enugu, Nigeria: Human health risks and economic cost of pollution.

This study assessed the human health risk of exposure to legacy PAHs in the Nwaenebo River sediments that received effluents for over two decades from the Nigeria National Petroleum Corporation (NNPC) petroleum product Depot in Emene, Enugu, Nigeria. The study went further to estimate economic costs of the sediment PAHs pollution based on the human health risk of exposure. The human health risks were determined by estimating carcinogenic and mutagenic risks via Benzo[a]pyrene total potential equivalent (BaP TPE) and mutagenic equivalent quotient (MEQ). The economic costs of the sediment pollution comprised costs due to mortality and those due to morbidity and were estimated using the value of statistical lives (VSLs) and cost of illness (CoI), respectively. The study, with an appropriate selection of sampling points established that the NNPC petroleum Depot was responsible for the Nwaenebo River sediment PAHs pollution with Æ©PAHs concentration 14.3-163 mg/kg. The carcinogenic and mutagenic risks varied from 1.3*10^-5 to 4.7*10^-5 and 1.4*10^-5 to 6.0*10^-5 respectively. Based on risk threshold of 10^-6, these risks were high. The long term economic costs of pollution of the sediments by the PAHs were estimated at 60.5 million USD and 0.46 million USD for mortality and morbidity costs, respectively.

Circular economy and frugal innovation: a conceptual nexus.

Frugal innovation (FI) and circular economy (CE) are two concepts that are recently being deliberated among researchers, policymakers, businesses, governments, and international organizations. Being a nascent development, both still lack an extant body of theories and data. Undisputedly they both share commonalities in gathering tractions among scholars. But the conceptual relationship between them has been unclear and hence makes it difficult to understand how one can promote the other. The current work constructs a conceptual framework through literature, explicating nexus, characteristics, and indicators of the two concepts and then exploring this framework through case analysis and focus group discussion (FGD). The results of our findings show that the two concepts are outcome of considerations on resource constraints and/or resource optimization; promote redesigning of product and services to minimize resources while achieving core functionality; involve the participation of stakeholders; and are implemented in stages. Most importantly, they foster the three pillars of sustainable development-social equity, economic prosperity, and environmental quality. However, supportive policies and institutions are largely associated with the development of CE which is not the same for FI in most countries. We conclude that FI being mainly operational in the emerging economies could serve as a veritable enabling tool for promoting the CE concept in the developing regions of the globe but will require the support of formal institutions and policies.

Co-production in solid waste management: analyses of emerging cases and implications for circular economy in Nigeria.

Co-production is a paradigm shift from the traditional model of public policymaking and service delivery that advocates for the involvement and participation of end-users of services as co-partaker in the process. In this paper, we examined the emerging models of co-production in solid waste management in Nigeria using a case study methodology. Four cases were purposefully selected for detailed exploration. The results of the analysis show that the involvement of the plurality of the non-state actors in waste management co-production brought in innovation through ICT, financial resources through grants, and increased public awareness. And have also given the service receivers a change of orientation that makes them perceive waste as a source of income rather than all rubbish needed to be discarded. However, possible exploitation of informal waste pickers, unclear business models, and absence of prior arrangement for coming together of both state and non-state actors in designing the service production are challenges to the emerging co-production cases. The current study further shows that the emerging co-production efforts have huge potential in promoting circular economy as it creates a better avenue for the implementation of extended producer responsibility (EPR), the establishment of eco-industrial parks, and safe integration of informal waste recyclers.

Natural leaf-type as food packaging material for traditional food in Nigeria: sustainability aspects and theoretical circular economy solutions.

Global call for healthy and sustainable food production and consumption has been loud, and the majority of these calls center on ensuring food security through sustainable agriculture. The other parts of the food supply chain such as consumption, packaging, recycling, and food waste management seem to be overlooked especially by developing nations of the world where attention is mainly placed on production. But in the broad sense, public health and environmental quality could be adversely impacted by neglect, mismanagement, or loophole on any of these food management systems. Hence, the current work studies the health and environmental impacts of local food packaging materials, adopting Nigeria as a proxy for the developing world. A review was first conducted to appraise the sustainability aspects of achieving and using natural leaves as a packaging material for traditional foods in Nigeria. The result of the review rightly shows that leaf-type packaging material has several apparent health and environmental advantages for food packaging. In view of this, the current work proposes a theoretical circular economy model that would ensure the constant and sustainable availability of these local packaging materials, especially in the urban centers.

Temporal assessment of municipal solid waste management in Nigeria: prospects for circular economy adoption.

This work reviewed the past and current status of municipal solid waste (MSW) management in Nigeria towards offering a direction for the future. The past status shows that poor policy regimes, inadequate financing mechanisms, absence of waste data, and abysmal institutional arrangement negatively impacted the MSW management outcomes in the country. At present, few improvements recorded like an increase in the number of landfills, and public-private partnerships have been largely undermined by the continuous upsurge in the urban population and lack of corresponding growth in critical capacities in terms of economic resources, technological advancement, and state-of-the-art urban infrastructures. The current waste generated in cities in Nigeria is calculated as 66,828 tonnes per day (TPD) at the total urban population of 106 million, while the projected value for 2040 will be 125,473 TPD at the urban population of 199 million. The current work further discusses prospects and implications for circular economy adoption in solid waste valorization in Nigeria.

Exposure risks to polycyclic aromatic hydrocarbons by humans and livestock (cattle) due to hydrocarbon spill from petroleum products in Niger-delta wetland.

In this study, the human and livestock (cattle) health risks of exposure to polycyclic aromatic hydrocarbons (PAHs) in a wetland of Obuaku, Abia State Nigeria contaminated by hydrocarbon spill due to incidents of hydrocarbon theft and pipeline vandalization were assessed. Gas chromatography-flame ionization detector and gas chromatography-mass spectrometry were employed in analyzing the TPH and PAHs respectively. The contaminated soil was delineated into sub-locations AOC-1, AOC-2, AOC-3, AOC-4, AOC-5 and AOC-6 to reflect the discrete patches (areas) of the contaminated site and for effective planning of remedial actions. The concentration of the PAHs in AOC-4 was insignificant but was quite significant in AOC-1, AOC-2, AOC-3 and AOC-6. The average percentage distribution of the PAHs in all the sites is 9.8% carcinogenic and 91.2% non-carcinogenic. The ecological risk assessment revealed that only sub-location AOC-4 contains PAH to a level of insignificant biological impairment while sub-locations AOC-1, AOC-2 and AOC-6 contain PAHs that pose the highest ecological risks. The assessment of health risk exposure to carcinogenic and non-carcinogenic PAHs indicated insignificant risks for all sub-locations whereas the assessment of health risks using PAH toxicity method indicates that only sub-locations AOC-1, AOC-2 and AOC-6 were toxic. These sub-locations were also found to be of significant health risks to livestock (cattle). Robust empirical models describing the relationships between TPH and any of the risk parameters were generated such that TPH can be used in predicting the risk parameters for spillage peculiar to petroleum products.

Crude oil polycyclic aromatic hydrocarbons removal via clay-microbe-oil interactions: Effect of acid activated clay minerals.

Acid treatment of clay minerals is known to modify their properties such as increase their surface area and surface acidity, making them suitable as catalysts in many chemical processes. However, the role of these surface properties during biodegradation processes of polycyclic aromatic hydrocarbons (PAHs) is only known for mild acid (0.5 M Hydrochloric acid) treated clays. Four different clay minerals were used for this study: a montmorillonite, a saponite, a palygorskite and a kaolinite. They were treated with 3 M hydrochloric acid to produce acid activated clay minerals. The role of the acid activated montmorillonite, saponite, palygorskite and kaolinite in comparison with the unmodified clay minerals in the removal of PAHs during biodegradation was investigated in microcosm experiments. The microcosm experiments contained micro-organisms, oil, and clays in aqueous medium with a hydrocarbon degrading microorganism community predominantly composed of Alcanivorax spp. Obtained results indicated that acid activated clays and unmodified kaolinite did not enhance the biodegradation of the PAHs whereas unmodified montmorillonite, palygorskite and saponite enhanced their biodegradation. In addition, unmodified palygorskite adsorbed the PAHs significantly due to its unique channel structure.

Removal of crude oil polycyclic aromatic hydrocarbons via organoclay-microbe-oil interactions.

Clay minerals are quite vital in biogeochemical processes but the effect of organo-clays in the microbial degradation of crude oil polycyclic aromatic hydrocarbons is not well understood. The role of organo-saponite and organo-montmorillonite in comparison with the unmodified clays in crude oil polycyclic aromatic hydrocarbons (PAHs) removal via adsorption and biodegradation was studied by carrying out microcosm experiments in aqueous clay/oil systems with a hydrocarbon degrading microbial community that is predominantly alcanivorax spp. Montmorillonite and saponite samples were treated with didecyldimethylammonium bromide to produce organo-montmorillonite and organo-saponite used in this study. Obtained results indicate that clays with high cation exchange capacity (CEC) such as montmorillonite produced organo-clay (organomontmorillonite) that was not stimulatory to biodegradation of crude oil polycyclic aromatic compounds, especially the low molecular weight (LMW) ones, such as dimethylnaphthalenes. It is suggested that interaction between the organic phase of the organo-clay and the crude oil PAHs which is hydrophobic in nature must have reduced the availability of the polycyclic aromatic hydrocarbons for biodegradation. Organo-saponite did not enhance the microbial degradation of dimethylnaphthalenes but enhanced the biodegradation of some other PAHs such as phenanthrene. The unmodified montmorillonite enhanced the microbial degradation of the PAHs and is most likely to have done so as a result of its high surface area that allows the accumulation of microbes and nutrients enhancing their contact.

Microbial degradation of crude oil hydrocarbons on organoclay minerals.

The role of organoclays in hydrocarbon removal during biodegradation was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. The clays used for this study were Na-montmorillonite and saponite. These two clays were treated with didecyldimethylammonium bromide to produce organoclays which were used in this study. The study indicated that clays with high cation exchange capacity (CEC) such as Na-montmorillonite produced an organomontmorillonite that was inhibitory to biodegradation of the crude oil hydrocarbons. Extensive hydrophobic interaction between the organic phase of the organoclay and the crude oil hydrocarbons is suggested to render the hydrocarbons unavailable for biodegradation. However, untreated Na-montmorillonite was stimulatory to biodegradation of the hydrocarbons and is believed to have done so because of its high surface area for the accumulation of microbes and nutrients making it easy for the microbes to access the nutrients. This study indicates that unlike unmodified montmorillonites, organomontmorillonite may not serve any useful purpose in the bioremediation of crude oil spill sites where hydrocarbon removal by biodegradation is desired within a rapid time period.

Effect of interlayer cations of montmorillonite on the biodegradation and adsorption of crude oil polycyclic aromatic compounds.

Cation exchange capacity, surface acidity and specific surface area are surface properties of clay minerals that make them act as catalysts or supports in most biogeochemical processes hence making them play important roles in environmental control. However, the role of homoionic clay minerals during the biodegradation of polycyclic aromatic compounds is not well reported. In this study, the effect of interlayer cations of montmorillonites in the removal of some crude oil polycyclic aromatic compounds during biodegradation was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. The homoionic montmorillonites were prepared via cation exchange reactions by treating the unmodified montmorillonite with the relevant metallic chloride. The study indicated that potassium-montmorillonite and zinc-montmorillonite did not enhance the biodegradation of the polycyclic aromatic hydrocarbons whereas calcium-montmorillonite, and ferric-montmorillonite enhanced their biodegradation significantly. Adsorption of polycyclic aromatic hydrocarbons was significant during biodegradation with potassium- and zinc-montmorillonite where there was about 45% removal of the polycyclic aromatic compounds by adsorption in the experimental microcosm containing 5:1 ratio (w/w) of clay to oil.

Biodegradation of crude oil saturated fraction supported on clays.

The role of clay minerals in crude oil saturated hydrocarbon removal during biodegradation was investigated in aqueous clay/saturated hydrocarbon microcosm experiments with a hydrocarbon degrading microorganism community. The clay minerals used for this study were montmorillonite, palygorskite, saponite and kaolinite. The clay mineral samples were treated with hydrochloric acid and didecyldimethylammonium bromide to produce acid activated- and organoclays respectively which were used in this study. The production of organoclay was restricted to only montmorillonite and saponite because of their relative high CEC. The study indicated that acid activated clays, organoclays and unmodified kaolinite, were inhibitory to biodegradation of the hydrocarbon saturates. Unmodified saponite was neutral to biodegradation of the hydrocarbon saturates. However, unmodified palygorskite and montmorillonite were stimulatory to biodegradation of the hydrocarbon saturated fraction and appears to do so as a result of the clays' ability to provide high surface area for the accumulation of microbes and nutrients such that the nutrients were within the 'vicinity' of the microbes. Adsorption of the saturated hydrocarbons was not significant during biodegradation.

Biodegradation and adsorption of C1- and C2-phenanthrenes and C1- and C2-dibenzothiophenes in the presence of clay minerals: effect on forensic diagnostic ratios.

The impact of modified montmorillonites on adsorption and biodegradation of crude oil C1-phenanthrenes, C1-dibenzothiophenes, C2-phenanthrenes and C2-dibenzothiophenes was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. Consequently, the effect on C1-dibenzothiophenes/C1-phenanthrenes, C2-dibenzothiophenes/C2-phenanthrenes, 2+3-methyldibenzothiophene/4-methyldibenzothiophene and 1-methyldibenzothiophene/4-methyldibenzothiophene ratios commonly used as diagnostic ratios for oil forensic studies was evaluated. The clay mineral samples were treated to produce acid activated montmorillonite, organomontmorillonite and homoionic montmorillonite which were used in this study. The different clay minerals (modified and unmodified) showed varied degrees of biodegradation and adsorption of the C1-phenanthrenes, C1-dibenzothiophenes, C2-phenanthrenes and C2-dibenzothiophenes. The study indicated that as opposed to biodegradation, adsorption has no effect on the diagnostic ratios. Among the diagnostic ratios reviewed, only C2-dibenzothiophenes/C2-phenanthrenes ratio was neither affected by adsorption nor biodegradation making this ratio very useful in forensic studies of oil spills and oil-oil correlation.

Effect of modified montmorillonites on the biodegradation and adsorption of biomarkers such as hopanes, steranes and diasteranes.

The effect of modified montmorillonites on the biodegradation and adsorption of selected steranes, diasteranes and hopanes was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. The unmodified montmorillonite was treated with didecyldimethylammonium bromide, hydrochloric acid and the relevant metallic chloride to produce organomontmorillonite, acid activated montmorillonite and homoionic montmorillonite respectively which were used in this study. The study indicated that organomontmorillonite, acid activated montmorillonite and potassium montmorillonite did not support the biodegradation of the selected steranes, diasteranes and hopanes as alteration of the biomarkers via biodegradation varied from a paltry 2-6 %. The adsorption of the selected biomarkers on acid activated montmorillonite and organomontmorillonite was also poor. However, adsorption of the biomarkers on potassium montmorillonite was relatively high. Sodium montmorillonite and unmodified montmorillonite appear to stimulate the biodegradation of the selected biomarkers moderately (30-35 %) with adsorption occurring at low level. Calcium montmorillonite and ferric montmorillonite effected significant biodegradation (51-60 %) of the selected biomarkers.

Compositional changes of crude oil SARA fractions due to biodegradation and adsorption on colloidal support such as clays using Iatroscan.

The compositional changes of saturates, aromatics, resins and asphaltenes (SARA) fractions in aqueous clay/oil microcosm experiments with a hydrocarbon-degrading microorganism community were analysed using Iatroscan. The clay mineral samples used in this study were organomontmorillonite, acid-activated montmorillonite and K, Ca, Zn and Cr montmorillonites produced by modifying the original montmorillonite sample. The evaluation and quantification of biodegradation and adsorption were carried out using a combination of the Iatroscan and gravimetric analysis. The SARA compositions in the presence of organomontmorillonite and acid-activated montmorillonite after incubation follow the same pattern in which the aromatic fraction is higher than the other fractions unlike in the presence of unmodified, K, Ca and Zn montmorillonites, where the saturates fraction is higher than the other fractions. Changes in SARA fractions due to biodegradation seemed to occur most in the presence of unmodified and calcium montmorillonites; hence, the removal of SARA fractions due to biodegradation was significant and enhanced in the presence of these two clay samples. However, biodegradation in the presence of organomontmorillonite and acid-activated and Cr montmorillonites was hindered. The study indicated that Cr montmorillonite adsorbed resins most, whereas Zn and K montmorillonites adsorbed aromatics most after incubation.