Sustainable development in a developing economy: Challenges and prospects

Sustainable development implies development which ensures maximization of human well being for today’s generation which does not lead to declines in future well being. Attaining this path requires eliminating those negative externalities that are responsible for natural resource depletion and environmental degradation. All human activities and developmental projects are associated with environmental degradation in one form or the other with the attendant generation of wastes. As a result of these, environmental problems of various types and intensities have emerged to threaten man’s wellbeing and the natural environment which serves as his life support system. In the light of the present global drive towards sustainable development and the concern of the Federal Government of Nigeria, fundamental strategies have been presented here to provide sound basis for comprehensive plans towards environmental management in Nigeria which is a fast developing economy. The basic paradigms of the interaction of man and the environment were used as basis for this study. The socioeconomic potentials of effective environmental management were presented. Application of the strategies has the potentials of contributing significantly to the national GDP and will also ensure that development is in harmony with the environment.Key words: Environment, degradation, sustainable, development, paradigms, pollution, recycling

SUBSTRATE REDUCTION KINETICS AND PERFORMANCE EVALUATION OF FLUIDIZED-BED REACTOR FOR TREATMENT OF BREWERY WASTEWATER

pilot scale anaerobic fluidized-bed reactor was operated for treating brewery wastewater at nine different hydraulic retention time (HRTs) of 2, 3, 4, 5, 6, 7, 8, 9, and 10hr. The COD reduction efficiencies increased from 9.8% to 74.1% with increasing HRT from 2 to 10hr.Similarly, the corresponding BOD5 reduction efficiencies increased from 38.0% to 92.9% with the same increase in HRT. The predicted effluent substrate concentration values of Modified Stover–Kincannon model were found to be in strong agreement with the experimental values. This is due to proper solubilization and consumption of entrapped substrates in the fluidized-bed reactor since the microbial cells have maximum opportunity to interact with the entrapped substrates in the reactor. The kinetic parameters were determined using existing linear models with experimental data. Modified Stover-Kincannon model showed high correlation coefficient (R2= 0.9996) only in predicted effluent concentration of wastewater. This shows that this model can be best used to predict effluent COD concentration in a fluidized bed reactor treating brewery wastewater. Similarly, FIRST ORDER MODEL has the highest correlation coefficient in the plot using experimental data. This means that first order model can be used to represent the real biological degradation that takes place during the treatment of waste water by microorganisms in a fluidized-bed reactor system treating brewery wastewater. This model and kinetic parameters obtained in this work can be employed in the design of industrial size- fluidized bed reactor for treatment of brewery waste water. Maximum utilization rate constant (Umax) determined is 11.75g COD/l.hr and the saturation value constant (KB) 131.41g COD/l.hr was also determined. The values of kinetic constants were also used to predict the effluent COD concentration. It was observed that the simulated data (predicted data) were in good harmony with the experimental data counterpart in modified Stover –Kicannon model, The strength of the  above-mentioned model can be observed from the correlation coefficient obtained from the model asR2 =0.9996 in modified Stover-kicannon model. http://dx.doi.org/10.4314/njt.v35i1.1

ALUMINA PHASE TRANSFORMATION FROM THERMAL DECOMPOSITION OF AMMONIUM ALUM SYNTHESIZED FROM KANKARA KAOLIN

Thermal stability of transitional alumina phases produced from ammonium alum using Kankara kaolin as starting material was studied. Wet beneficiation method was employed to purify the starting material, after which it was calcined and dealuminated with sulphuric acid. The elemental composition, mineralogical, and physiological analyses were carried out using X-ray fluorescence (XRF), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) techniques respectively. The ammonium alum was thermally treated by varying the calcination temperature from 700 to 1200°C and varying the time of calcination from 1 to 4 h. The formation of gamma alumina began at calcination temperature of 825°C for calcination time of 3 h, which was found to be lower than reported works of 900°C. It was found to be stable at higher temperature of 1125°C, above which phase transformation to alpha alumina was observed. The observed wide range of thermal stability of the gamma alumina phase gives it good advantage to be used for high temperature applications, such as support for catalyst promoters. Alpha alumina phase formation began at 1150°C and was fully formed at 1200°C. BET specific surface area of 166 m2/g was obtained for the gamma alumina phase which was high enough for it application as support for catalyst, catalyst and adsorbent. http://dx.doi.org/10.4314/njt.v36i3.2

Modelling and Simulation of Coking in the Riser of an Industrial Fluid Catalytic Cracking (FCC) Unit

Under normal Fluid Catalytic Cracking (FCC) conditions, coke is the most important factor that affects catalyst activity. A pseudo homogeneous two - dimensional (2D) model of an industrial FCC riser is here presented. The FCC riser models of previous researchers were mostly based on the assumption of negligible mass transfer resistance and 1D plug flow. These assumptions undermine the accuracy of the models by over-predicting the riser residence time while under-predicting the reaction time. Mass transfer resistance was incorporated in the reactor model to enhance the accuracy of the results. Finite difference was used to discretise the model equation. This investigation has advanced research into the modeling of FCC riser by predicting catalyst coke content as a function of reaction temperature. The yields of LCO, gasoline, gas and coke that were predicted by the model for industrial risers were 15.54wt%, 49.70wt%, 18.01wt% and 4.90wt% respectively. A feed stock (VGO) conversion of 79.28% was predicted by the model. An optimal operating temperature range of 786K<T<788K was predicted for the riser.http://dx.doi.org/10.4314/njt.v34i2.1

Design and Construction of Pilot Scale Process Solvent Extraction Plant for Neem Seed Oil

A pilot Neem oil solvent extraction plant of 9.65kg/day Neem seed kernel capacity was designed and fabricated. Grade 304 stainless steel was used for construction of the extractor, evaporator, condensate receiver and the flat blade turbine impeller. The concept of overall heat transfer coefficient was adopted for calculating the heat transfer areas of the extractor and evaporator and their sizing. The extraction was carried out at 50oC extraction temperature and particle size of 0.425 – 0.710mm at an efficiency level of 81.91%. The percentage yield obtained was 36.86% when flat blade turbine impeller was operated at 84 rpm for 40 minutes contact time. The GCMS result shows the composition of the extracted Neem oil to be oleic acid, 40.41%; stearic acid, 27.65%; palmitic acid, 25.36%; octanal, 3.90%; elaidic acid, 1.23%; lactone, 0.97%; and methyl stearate, 0.48%. This percent composition compares favourably with literature values. The properties of the Neem oil were found to be: specific gravity, 0.9111; pH, 6.5; refractive index, 1.4668; iodine value, 70.21g/g; acid value, 34.33mgKOH/g and Saponification value, 180.95 mgKOH/g

THE STUDY OF THERMAL EFFECT ON THE SURFACE PROPERTIES OF GAMMA-ALUMINA SYNTHESIED FROM KANKARA KAOLIN.

Gamma alumina is a good material for catalyst support and its surface properties is of great importance. In this study the gamma-alumina (γ-Al2O3) synthesized to be used as catalyst support for zeolite catalyst was obtained by calcination of ammonium alum an intermediate product prepared from kaolin which was sourced from Kankara, Katsina, Nigeria. The surface properties were determined using BET technique. BET specific surface area of gamma alumina produced at 825°C for soaking time of 3h was 120m2/g while at 850°C for soaking time of 4h the surface area was 140m2/g. The pore size and pore volume range from 15nm to 25nm and 0.5cm3/g to 0.8cm3/g respectively. The XRD pattern obtained at 825°C and 875°C calcination temperatures conformed to the standard pattern of gamma-alumina, having the strong peaks at Bragg angles of 67, 46, 39 and 38°. The SEM image showed clearly the plate-like structure of gamma alumina. Thus kankara kaolin is a promising material for the production of gamma alumina. http://dx.doi.org/10.4314/njt.v35i1.1

DEVELOPMEMT OF PILOT SCALE DEALUMINATION UNIT OF 2.5 kg METAKAOLIN PER BATCH CAPACITY

A pilot-size dealumination unit to handle 2.5kg of metakaolin per batch was designed and fabricated and test run. The metakaolin was prepared from Kankara kaolin. The metakaolin was completely split into silica and alumina. The silica component which was inert to the sulphuric acid used during the reaction and was obtained as a solid product. While the alumina which reacted with the sulphuric acid was obtained in liquid form as aluminum sulphate, known as alum. The dealumination unit comprises of the dealumination reactor, known as dealuminator, acid holding tank and metakaolin slurry mixing tank. The material of construction selected for the dealumination reactor was stainless steel type 304 lined internally with glass to withstand the corrosive environment of the concentrated sulphuric acid at the reaction temperature > 140°C. The capacity of the componentsare; acid holding tank 5 liters;metakaolin slurry mixing tank 20 liters, with 70 W capacity motor and the dealuminator 50 liters, which had pressure relief valve, pressure gauge (0-10 bars) and temperature gauge (0 - 300°C) on the cover. Woven glass fiber cloth was used as lagging material to minimize heat lossto the surrounding. The purity level of the silica obtained from the reaction was above 95%.The endothermic nature of the dealumination process was void of external heating. http://dx.doi.org/10.4314/njt.v36i3.2

Chemical and Physical Comparative Study of the Effect of Wet and Dry Beneficiation of Kankara Kaolin

Chemical and physical comparative effect of wet and dry beneficiation processes for purification of kaolin was studied. X-ray flourescence XRF and particle size analysis of kaolin clay before and after beneficiation were carried out. The Si/Al ratio of the raw kaolin which was 1.90 decreased by 1.6 and 17.9% after the wet and dry beneficiation processes respectively. The clay content of the raw clay which was 48 wt% was improved to 73 wt% after the dry beneficiation while the impurity content was reduced from 52 to 27wt%.http://dx.doi.org/10.4314/njt.v34i2.1

A study of the efficacy of 5- day radical treatment of primaquine in Plasmodium Falciparum cases in Nnewi, Nigeria

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