Assessment of air pollution in residential areas : a case study of Kinondoni Municipality, Tanzania

Published ArticleAir pollution, just like any other type of pollution, produces harmful effects to man and his environment. In spite of knowing this, many less industrialised countries of the world have no air quality monitoring strategies in place. Consequently, documented evidence of air pollution studies in such countries is scarce. This is the case in Tanzania. This scenario is made worse by lack of scientific tools which could aid in identifying air pollution-prone areas with a view to aiding town planners in locating safe sites for schools, hospitals and residential areas as well as parks. In this paper, we present results of a study carried out in the city of Dar-es-Salaam, Tanzania on air pollution in residential areas. Results show significant air pollution in the studied areas. Moreover, both adults and children are at risk due to lead pollution in the air

Nigeria’s Legal Instruments for Land and Water Use: Implications for National Development

This chapter critically assesses the administration of land and water resources in Nigeria. Reasons why the Land Use Act has not met its objectives are discussed. It also assesses reasons why despite abundant water resources, numerous laws, and multiple governing institutions, Nigeria is still struggling to meet the national demand for water supply. The chapter concludes by suggesting specific amendments to the administration of both land and water resources. The main thrust of the suggested amendments is to address the current situation where government arrogates absolute authority on all land and water resources to itself. It is suggested that the government should consider adopting a multi-lateral relationship where government, private investors, traditional land owners, and prospective land buyers are co-decision makers in charting the future for the administration of land and water resources. This is aimed at eliminating associated problems such as delays, tenure insecurity and proliferation of peri-urbanization the current system

Surface and Groundwater Research in South Africa: An Undergraduate Class Experience.

A group of young students were engaged in researching into some of South Africa’s water problems. Being a semi-arid country with huge deficits in water supply, both surface and groundwater resources in the country are critical and have been fully allocated. However, it was found that pollution activities are putting additional strain on the already sparse water resources, thereby effectively reducing available fresh water in the country. The identified sources of pollution of surface waters in South Africa are agricultural drainage and run-off (irrigation return flows, fertilizers, pesticides and runoff from feedlots), urban wash-off and effluent return flows (bacteriological contamination, salts and nutrients), industries (chemical substances), mining (acids and salts) and areas with insufficient sanitation services (microbial contamination). Pollution of groundwater results from mining activities, leachate from landfills, human settlements and salt water intrusion from the surrounding oceans. The undergraduate students’ hands on experience in this research work involved both field work and class presentations. This experience stimulated an interest in the students which was not in them ab initio. The students had a better understanding of the problems in their environment. Many of them also indicated interest in furthering their studies at graduate level in the identified environmental and geological areas

Municipal wastewater management using Vetiveria zizanioides planted in vertical flow constructed wetland

This study investigated wastewater management using Vetiveria zizanioides planted in vertical flow constructed wetland (VFCW). Wastewater from the grit removal chamber and the primary sedimentation tank of Daspoort Wastewater Treatment Works was fed into six-pilot VFCW consisting of 1000-L plastic tanks having 500-mm-deep, 10–15-mm-diameter granite substrate planted with V. zizanioides. Irrigation of macrophytes using effluent from the grit removal chamber and primary sedimentation tanks was done after 3 months of planting and the VFCW monitored. Wastewater samples were collected and analysed using standard procedures. The pollution parameters of the initial sample were total alkalinity 297 ± 27.3 mg/L; COD 627 ± 149.0 mg/L; EC 82.53 ± 5.4 ms/m; free and saline ammonia 36.02 ± 4.1 mg/L, nitrate/nitrite 0.09 ± 0.1 mg/L; pH 7.66 ± 0.4; phosphate 3.07 ± 0.3 mg/L, sulphate 44.57 ± 3.1 mg/L; TDS 551 ± 37.8; TSS 319 ± 34.2 mg/L; and TKN 41 ± 6 mg/L. Percentage removal of 89.57, 98.34% TSS; 98.95, 98.62 free and saline ammonia; 89.87, 91.44% TKN; and 80.65, 58.02% COD for screen and settled wastewater, respectively, was obtained from the VFCW. VFCW using locally available V. zizanioides is a viable alternative for municipal wastewater treatment

Sustainable Green Environment through Utilization of Waste Soda-Lime Glass for Production of Concrete

Recycling and reuse of waste materials remains a major option for waste reduction, preserving the natural resources from further depletion and reduction in greenhouse gases emission thereby contributing to sustainable green environment. In this study, focus on the reuse of waste soda-lime glass crushed into coarse aggregate sizes as a substitute for natural coarse aggregate in normal concrete was investigated. The variables in this study is coarse aggregate while the cement, sand and water-cement ratio were held constant. The crushed waste glass was varied from 0 – 100% in steps of 25% by weight to replace the coarse aggregate in the concrete mix. Concrete mixes were prepared using a mix proportion of 1:2:4 (cement: sand: granite) at water-cement ratio of 0.5 targeting a design strength of 20 MPa. Slump tests were carried out on fresh concrete mixes and tests were also carried out on total number of 60 concrete cube specimens of size 150 x 150 x 150 mm and 60 concrete cylinder specimens of dimension 100 mm diameter by 200 mm height after 3, 7, 28 and 90 days of curing. Results on the slump tests shows a decrease in the concrete workability as the glass content increases. Test results also 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 normal concrete

Waste management practices in Nigeria: Impacts and mitigation

We reviewed the current state of waste management practices in Nigeria using examples from different parts of the country. Commonly practiced waste disposal methods in Nigeria, such as burial, open-air burning, and open dumping, were found to be ineffective and detrimental to public health and the environment. It was also shown that waste management cannot be successfully operated as a social service. Rather, the generator of waste must be held responsible. Problems confronting efficient waste management in Nigeria include the proliferation of unplanned settlements, traffic congestion, insecurity, and ignorance. An experimental model being used in Lagos State for the management of wastes may be the solution. Given the rate of population growth, industrialization, and urbanization, forward-looking and effective waste management plans need to be set in motion for the protection of public health. Such plans must involve all stakeholders, including the waste generators, the private sector, the informal sector, and regulatory agencies

Municipal wastewater treatment using sequential activated sludge reactor and vegetated submerged bed constructed wetland planted with Vetiveria zizanioides

This study investigated a sequential system consisting of Biological Nutrient Removal Activated Sludge(BNRAS) and Vegetated Submerged Bed Constructed Wetlands (VSBCW). The BNRAS/VSBCW combination removing pollutants from municipal wastewater in a developing country was examined. Wastewater from the anaerobic, anoxic and aerobic zones of the BNRAS was fed into 12 pilot VSBCW consisting of 1000 L plastic tanks having 500 mm deep 10–15 mm diameter granite substrate planted with Vetiveria Zizanioides. Irrigation of macrophytes using effluent from the BNRAS was done after 3 months of planting and the VSBCW effluent analyzed. Wastewater samples were collected and analyzed using standard procedures. Percentage removal of 96.6, 96.93, and 97.21% of COD; 33.33, 85.71, and 92.48% of Nitrate/Nitrite;53.51, 46.45, and 88.78% of Sulphate; and 98.34, 99.72, and 99.6% of TSS were obtained from the anaerobic, anoxic and aerobic zones respectively. Removal efficiency from the anaerobic zone effluent was highest during the study period. VSBCW using locally available macrophytes V. Zizanioides in combination with BNRAS was found efficient in municipal wastewater treatment

Structural Properties of Concrete Containing Ground Waste Clay Brick Powder as Partial Substitute for Cement

With the increasing concerns on the impact of cement production on the environment and the need to protect the environment, the use of mineral additives as cementitious material to partially substitute cement is being considered as an effective option. One of such material is fired clay brick which can be sourced as generated waste from clay brick industry. This has an added advantage of reducing industrial waste and preserving the natural resources. The experimental objective of this study is to examine the possibility of utilizing clay brick waste as partial replacement for Portland cement in concrete. The clay brick was finely ground into powder size, and after grinding, the morphological characterization of the powder materials was carried out using scanning electron microscopy (SEM). Moreover, the chemical composition of the brick material was determined using X-ray fluorescence (XRF). Laboratory tests were carried out to determine the workability, split tensile and compressive strength properties of the concrete with 0%, 10%, 20%, 30% and 40% partial replacement of cement with ground clay brick (CB). From the test results, the chemical composition of the brick powder meets the standard requirements for pozzolanic material, with the SEM revealing an amorphous solid mass. The workability of the concrete reduces with increase in brick powder content. A significant improvement of the split tensile and compressive strength of the concrete was achieved at 10% cement replacement, after which a decrease in strength with increasing ground clay brick content was recorded. The use of ground clay brick of not more than 15% was recommended for concrete productio

Characterization of ceramic waste aggregate concrete

There is a growing interest in using waste materials such as ceramics as alternative aggregate materials for construction. While other ceramic product wastes such as sanitary wares and electrical insulators have been extensively investigated, not much findings are available on ceramic wall and floor tiles wastes. Thus, the current study focuses on the mechanical characterization of waste ceramic wall and floor tiles aggregate concrete. Ceramic wastes sourced from construction and demolition wastes were separated from other debris and crushed using a quarry metal hammer. Ceramic tiles were sieved into fine and coarse aggregates in line with standards. Other materials used were gravel, river sand, cement and potable water. Workability of the fresh concrete was checked through slump test, and concrete cubes of 150 mm dimensions and cylinders of 100 mm � 200 mm were cast in the laboratory. After 24 h of casting, the concrete samples were demolded and were cured by immersion in water tank at temperature of 22 �C. The compressive and split-tensile strengths of the hardened concrete samples were determined after curing them for 3, 7, 14 and 28 days. Results showed that both the compressive strength and split tensile strength increased appreciably with the curing age than the conventional concrete

Application of Waste Glass Powder as a Partial Cement Substitute towards more Sustainable Concrete Production

Use of waste materials in concrete is now a global trend for efficient waste management so as to achieve a sustainable green environment and with the added advantages of preserving the natural resources as well as producing a better performing concrete. This study examined the properties of concrete containing ground waste glass powder (GP) as partial replacement for cement. The waste glass was finely grounded into powder and the morphology imagery of the powder materials was carried out using scanning electron microscopy (SEM). Moreover, the chemical composition of the glass powdered material was determined using X-ray fluorescence (XRF). Laboratory tests were carried out to determine the strength activity index, workability, split tensile and compressive strength properties of the concrete with 0%, 15%, 18%, 21%, 24%, 27% and 30% partial replacement of cement with the ground waste glass powder. The results showed that the oxides composition of the glass powder meets the requirements for pozzolanic material, while the SEM morphology shows materials of amorphous flaky solid masses, and based on the 28-day strength activity index, concrete containing 21% cement replacement shows a higher strength index above the recommended 75%. It was also observed that workability of the concrete reduced with increase in percentage glass content while significant improvement of the compressive strength of the concrete was achieved at 21% cement replacement, after which a decrease in strength with increasing percentage glass content was observed. The revealed results were confirmed by the microstructural examination using SEM showing a denser concrete at 21% cement replacement but increase porosity as the glass content increases. However, a decrease in split tensile strength was observed with increasing glass content. The results clearly showed that it is possible to produce moderate strength sustainable concrete for structural application using 20% glass powder as cement replacement