David O. Olukanni

Appraisal of Municipal Solid Waste Management, Its Effect and Resource Potential in A Semi-Urban City: a Case Study

Managing municipal solid wastes (MSW) is progressively becoming a major challenge in many cities of developing nations because of rapid urbanization and rise in population. This can be described by ineffective collection methods, inadequate coverage of the collection, processing system and inappropriate disposal. This paper presents the current state of solid waste management in a semi-urban city, its associated challenges and prospects that are within. A field work that involves the characterization and types of the waste generated, and frequency of collection was carried out within the study area. Four locations where the major waste bins are located within the city were considered. A representative sample of 280 kg was used for the waste characterization, and the results show that about 64% of the wastes are recyclable with lots of organic waste that can be used as compost. The only dump site in the city was visited in order to obtain useful information concerning the present state of solid waste management. The study revealed that there is presently no investment made to the existing development plan to introduce a modern waste management system. The study suggests new approach that could be used by institutions and government agencies for MSW management to realize a sustainable and efficient sanitation, and possible resources generation potentials that could be harnessed from the waste stream.

Assessment of Impact of Hydropower Dams Reservoir Outflow on the Downstream River Flood Regime – Nigeria’s Experience

Over more than five decades, the energy sector in Nigeria, particularly the rural energy sector, is characterized by lack of access, low purchasing power and over-dependence on traditional fuels for meeting basic energy needs. In an attempt by the government to solving this challenge, the hydropower scheme came on stream as the forerunner in 1968, 1986 and 1990 at Kainji, Jebba and Shiroro respectively. The objective was to improve access to reliable, secure, affordable, climate friendly and sustainable energy services and to boost investment in energy in Nigeria. However, this solution seems to be characterized with some challenges at the downstream sector of the hydropower dams. The communities in the flood plains experience annual flooding when the authorities of Power Holding Company of Nigeria (PHCN) open the gates of the dams to let off water at the peak of the rains. The floods have caused damages and untold hardships to lives and properties. The occurrence of flood has great effect on communities and farming activities downstream of Jebba and Shiroro dams.

Effect of Substitution of Crushed Waste Glass as Partial Replacement for Natural Fine and Coarse Aggregate in Concrete

Reusing of waste glass in concrete production is among the attractive option of achieving waste reduction and preserving the natural resources from further depletion thereby protecting the environment and achieving sustainability. This present study examines the possible reuse of waste glass crushed into fine and coarse aggregate sizes as partial substitute for natural fine and coarse aggregate in concrete. The variables in this study is both the fine and coarse aggregate while the cement and water-cement ratio were held constant. The crushed glass was varied from 0 – 100% in steps of 25% by weight to replace the both the natural fine and coarse aggregate in the same concrete mix. Concrete mixes were prepared using a mix proportion of 1:2:4 (cement: fine aggregate: coarse aggregate) at water-cement ratio of 0.5 targeting a design strength of 20 MPa. Tests were carried out on total number of 90 concrete cube specimens of size 150 x 150 x150 mm and 90concrete cylinder specimens of dimension 100 mm diameter by 200 mm height after 3, 7, 14, 28, 42 and 90 days of curing. Test results indicated that the compressive and split tensile strength of the hardened concrete decreases with increasing waste glass content compared with the control. However, concrete mix made with 25% waste glass content compared significantly well with the control and can be suitably adopted for production of light weight concrete.

Progression in Waste Management Processes in Lagos State, Nigeria

One of the challenges of Lagos State is efficient and cost-effective solid waste management. This paper focuses on progress made in waste management operations in the State. An assessment to know how waste generation, collection, transportation and disposal have put demands on state resources, and its physical infrastructure was carried out. The state generates about 12,000 metric tons of waste daily (0.72kg/person/day). Due to limited budgetary allocation, the state government instituted the Lagos State Waste Management Authority (LAWMA) to perform supervisory roles and charged with the implementation, advocacy, monitoring and enforcement of waste management policies. As part of its roles, the agency enlisted Private Service Providers (PSP) for the purpose of appropriate billing of waste services. LAWMA centrally collects revenue and remits agreed portion of 60% of waste charges to individual PSP accounts in accordance to estimated waste collected. The state is focused on resource recovery programs such as composting, land filling and pelletizing of plastics and nylons. The implications (environmental, economic, social and financial) for managing solid waste gives credence to the renewal campaign for resource conservation and environmental sustainability. Thus, the 4 Rs of waste management – Reduction, Reuse, Recovery and Recycling are being demonstrated through establishment of compost production plant, championing of Waste-To-Wealth Initiatives and Renewable Energy (RE).

Diameter Inconsistency, Strength and Corrosion Characteristics of Locally-Produced and Imported Steel Reinforcing Bars in Ilorin, Nigeria

There has been increasing incidents of collapse of reinforced concrete buildings in Nigeria. Many research works, suspecting the quality of concrete produced in Nigeria, have focused on concrete with few attention on steel, perhaps because its production is usually in a more controlled environment. Over the years, many clients of building construction projects or their representatives have shown preference for imported steel bars over the locally-produced steel bars. This research work sets out to investigate the quality of steel reinforcement produced locally and compare them with imported steel bars. The diameter of the two classes of bars available in the open market at Ilorin, Nigeria were measured and their deviations from their manufacturer’s designated diameter were determined. Also, their response to the application of load and deterioration in different environments, simulated by their immersion in water, hydrochloric acid (HCL) and sodium hydroxide (NaOH), were studied. Locally-produced bars deviated more from their designated diameter than the imported bars. The imported steel bars have higher strength and experienced lower strain compared to the locally produced steel. They also showed better corrosion resistance, when immersed in distilled water and HCL, than the locally-produced steel bars. The preference for imported steel by clients of building projects is justified.There is a need for regulatory bodies, such as the Standards Organization of Nigeria (SON), to strictly monitor and penalize local steel manufacturers that engage in corrupt practices leading to significant dimensional and strength deviations from specification. This has the potential of minimizing the incidence of building collapse in Nigeria.

Study of Reed-bed of an Urban Wastewater in a Nigerian Community

The need for treatment of municipal wastewater prior to its disposal is important. One method used for treating wastewater is that of a constructed wetland system (CW). The use of a CW has attracted interest in developing nations due to its operational efficiency and cost effectiveness. This paper examines an existing CW in order to determine its effectiveness in the removal of pollutants from a sewer that feeds into a major river system in Nigeria. The CW, which employs hydrophytes to degrade the wastewater from a facility of nearly 10,000 people, is comprised of six cement-block tanks. Samples were collected from the entry and exit points of the CW’s cells and analysed for dissolved oxygen, conductivity, pH and temperature. The pH remained constant (6.8 - 6.9) at ambient temperature of 270C. Conductivity ranged from 700 to 840 ppm. The dissolved oxygen (DO) ranged from 0.9mg/l at the entrance to 0.1 mg/l at the final exit point. Analysis of the data suggests that the CW is not efficient, and steps -- like aeration and an increase in the resident times of the wastewater in each cell of the CW -- need to be taken to improve its performance.

Optimization-based reliability of a multipurpose reservoir by Genetic Algorithms: Jebba Hydropower Dam, Nigeria

Abstract This study is focused on the application of Genetic Algorithm (GA) as an effective tool for modeling the operation of a multi-purpose reservoir with specific emphasis on Jebba Hydropower Dam, Nigeria. The specific objectives are to study the reservoir operation rule; model the reservoir parameters such as inflow, elevation, turbine release, generating head, energy generation, tailrace water level and plant coefficient. Available Data for 27-year period (1984–2011) was obtained from the Dam Station for statistical analysis. MATLab software for GA was used, and for comparison and check, another similar optimization software (LINGO) was utilized. The optimal solution obtained at operating performance of 50% reservoir inflow reliability has total annual energy generation of 42,105.63MWH. GA for the total annual energy generation at operation performance of 95, 90 and 75% reservoir inflow reliability are 15,964.48 MWH, 21,009.53 MWH and 20,798.58 MWH, respectively. The application of GA will lead to a more realistic and reliable optimal value for the improvement of hydroelectric power generation and flood management, which would guide decision makers in the hydropower sector.

Estimating greenhouse gas emissions from port vessel operations at the Lagos and Tin Can ports of Nigeria

Abstract Greenhouse gas (GHG) emission, the number one contributor to global warming is not just a product of in-land transportation, industries and other anthropogenic effect but also the maritime and shipping industries. This article estimates the amount of greenhouse gases emitted from port vessel operations in the Lagos and Tin Can ports of Nigeria. The emission estimate was carried out based on the type of the vessel and its movement from the moment of its arrival (400 km from the coast). The emission estimate was done using the bottom-up approach based on the characteristics of individual vessels and using data on vessels processed by both ports in the first and second quarter of the year 2017. Among various types of vessels, Premium Motor Spirit (PMS) carriers are the heaviest emitters, followed by the container vessels and general cargo vessels. Result for the first and second quarter of 2017 indicates that approximately 16,335 t and 773 t of CO2 were produced and emitted during anchorage and while passing through lock gates movement, respectively. Also, 644 t of CO2 was emitted through maneuvering to the dock movement. Consequently, these three movements account for 85% of the total CO2 emission from Lagos and Tin Can ports. These emissions are known to contribute to lung cancer, cardio vascular and cardio pulmonary functions, allergies and asthma, particularly for the inhabitants of communities lying along the sea shore. However, if provisions are made for electricity from land, about 5% of the estimated emissions during cargo handling can be avoided.

Experimental Study on the Workability of Self-Compacting Granite and Unwashed Gravel Concrete

This study deals mainly with the mix proportions using granite and unwashed gravel as coarse aggregate for self-compacting concrete (SCC) and its workability, by considering the water absorption of unwashed gravel aggregate. Mix proportions for SCC were designed with constant cement and fine aggregate while coarse aggregates content of granite-unwashed gravel combination were varied in the proportion 100%, 90%/10%, 80%/20%, 70%/30%, 60%/40%, 50% /50%, represented by SCC1, SCC2, SCC3, SCC4, SCC5 and SCC6. 100% granite (SCC1) serves as the control. The workability of the samples was quantitatively evaluated by slump flow, T500, L-box, V- funnel and sieve segregation tests. Based on the experimental results, a detailed analysis was conducted. It was found that granite and unwashed gravel with SCC1, SCC2 and SCC3 according to EFNARC (2002) standard have good deformability, fluidity and filling ability, which all passed consistency test. SCC1, SCC2 and SCC3 have good passing ability while all mixes were in the limit prescribed by EFNARC (2002). It can be concluded that the mix design for varying granite-unwashed gravel combination for SCC presented in this study satisfy various requirements for workability hence, this can be adopted for practical concrete structures.

Assessment of Gravel Properties Sourced within Oyo North Senatorial District: Case Study of Ogbomoso

The study evaluated the properties of gravel aggregate sourced within Oyo north senatorial district for concrete production in place of crushed granite crushed at exorbitant cost since characteristic properties show significant reflections on the qualities of gravel aggregate used and also play major role in determining the properties of hardened concrete.Samples of gravel from four commonly used borrow pits: Aroje, Bolanta, Sunsun and Olomi sites were obtained and tested for Aggregate Crushing Value (ACV), Aggregate Impact Value (AIV), Specific Gravity, Water absorption Capacity, Bulk Density, Moisture Content and Particle Size Distribution.On the average the results of the observation for the selected four locations were 22.56 g, 28.17 g, 33.37 g and 40.19 g for Aggregate Crushing Value (ACV), 2.44 g/ml, 2.53 g/ml, 2.57 g/ml and 2.62 g/ml for Bulk density, 0.17 %, 1.43 %, 2.42 %, and 2.48 % for moisture content, 2.02 %, 2.92 %, 2.00 % and 3.15 for water absorption, 2.52, 2.63, 2.60 and 2.55 for specific gravity, 41. 55 %, 45.25 %, 45.59 % and 47.08 % for aggregate Impact respectively.The study revealed that, gravel aggregates from Aroje has superior properties over those of Sunsun, Bolanta and Olomi as compared with coarse aggregate properties in BS 812: 1995 and BS 882: 1992. It is hereby recommended for coarse aggregate in concrete production.