Physics, Engineering and Material Science

Permanent URI for this collection

http://openscience.utm.my/handle/123456789/30

Browse

Now showing 1 - 5 of 408

Biogranulation development during treatment of real textile wastewater
(Universiti Teknologi Malaysia, 2018) Krishnen, Ranjeni
Over the past decades, effluent discharge from textile industries to neighbouring water bodies can cause severe water pollution if discharged untreated. There are quite a number of treatment systems have been invented to treat textile wastewater, but each treatment system had its own limitations. The most common limitations are low efficiency, inapplicability to treat a wide variety of dyes, production of secondary waste and high cost. Currently, biological treatment using biogranules had showed promising results in treating textile wastewater. However, most studies are being done using synthetic wastewater at lab scale reactor. This study looks at the development and application of biogranules in treating the actual textile wastewater using pilot-scale reactor. A pilot-scale Sequential Batch Reactor (SBR) biogranular system with working volume of 70 L was developed and operated according to SBR’s sequence for 24-hr cycle, which includes sequential anaerobic and aerobic reaction phases. Wastewater from two textile mills were used as feed, while sewage and pineapple wastewater were used as co-substrate. After operating the system for 60 days, 30% of the sludge transformed into biogranules and increased to 67% at the end of the study. The biogranules developed in the reactor have sizes ranging from 0.2 mm to 9.5 mm with a mean settling velocity of 28 ± 7 m/hr and Sludge Volume Index (SVI) of 73.9 mL/g. At the end of the development period, the system yields 92% removal of Chemical Oxygen Demand (COD), however color removal fluctuated throughout the development period in the range of 50 to 70%. The efficiency of biogranules in treating textile wastewater was evaluated using lab scale bioreactor with total working volume of 3L. The system was able to achieve 55% of average color removal and 88% of average COD removal at 7%v/v pineapple wastewater concentration during the treatment period. The experiment on treatment of raw textile wastewater without any added nutrient proved the importance of co-substrate in dye degradation. Conversely, the addition of external dye degrader microbes in the reactor had slightly improved color removal. The system obtained 59% of mean color removal and 81% of mean COD removal at 5%v/v pineapple wastewater concentration upon addition of dye degrader microbes into the bioreactor. Microorganisms under genus Pseudomonas, Klebsiella and Enterococcus were identified within the mature biogranules which are considered in the literature as dye degrader microbes. Although the biogranules development is much faster in lab-scale reactor under controlled environment, the findings indicate the feasibility of developing biogranules in a bigger scale reactor using actual textile wastewater and other high-strength biodegradable wastewater as co-substrate
Water supply reservoir operation in the framework of climate variability and change
(Universiti Teknologi Malaysia, 2013) Ismail, Tarmizi
The optimal planning and operation of a reservoir system is getting more crucial particularly in view of the recent awareness of potential climate change. In particular, the incorporation of hydrologic uncertainties due to climate change into reservoir operation system requires comprehensive and long-term hydrological database which rarely available in most of the conventional reservoir design. The prime objective of the study is to formulate a multiple approach on the long-term reservoir operation optimization under the scarcity of observed hydrological data and with the influence of climate change. A combined research method using IHACRES for hydrological simulation, HadCM3 for emission scenario and Statistical Downscaling Model were developed along with a Mixed Integer Linear Programming (MILP) for reservoir operation optimization. These approaches were applied to a single purpose Sg Layang Resevoir, that is one of the most prominent water supply reservoir located in Johor State, Malaysia. The climatic variables obtained from general circulation model (GCM) were downscaled corresponding to HadCM3 emission scenario and used in climate change impact analysis. The SDSM was used to produce 100 synthetic climate time-series for 90 years of the participating station, representing the climate change projection and baseline period. With respect to the baseline data, an apparent increase in temperature (1.2 degree Celsius between time periods) and rainfall was observed. The deterministic optimization exercise is performed repetitively for a number of case scenarios based on weekly reservoir’s inflows derived from the projected climate change in a way to determine the optimal operation rule and policy which are based on total pumping volume and pumping cost. Corresponded to the future inflows, the pumping volume has shown an increase trend particularly during southwest monsoon, transition between seasons and autumn. Judged from the decreasing rate of the streamflows, a 34 to 40% increase in the projected monthly pumping volume is anticipated. An opposite scenario is observed during northeast monsoon season which shows a decreasing trend of 28% to 46%. At various degree of statistical reliability, the optimal operational pumping curves of the reservoir were established. These curves provide some basic information on the monthly pumping requirement from various sources of inflow to sustain the reservoir storage and demand. These operation curves are of very useful guidelines for reservoir operators in making decision to follow an optimal pumping operations schedule onsite. Such research findings were expected to generate a general awareness to the public water authorities on the potential long term effect of climate change to the reliability of reservoir operating system
Simulation model of traffic operations on single carriageway roads
(Universiti Teknologi Malaysia, 2018) Bujang, Zamri
A traffic model should be developed to evaluate the effect of road layouts and traffic characteristics on traffic operations. This research is conducted to investigate traffic behaviour on single carriageway roads. The effect of various road layout, Heavy Goods Vehicles (HGVs), overtaking provisions and traffic directional split on capacity and speed has been evaluated. This simulation model has the ability to represent traffic operations on single carriageway roads and priority junctions at or near capacity for a varied range of road layouts and traffic characteristics. The model was calibrated and validated by using field data from Johor Bahru and results from previous studies. The model development process includes input data, simulation and output data. The simulation process involves of driver behaviour which consist of car following, overtaking and lane changing. The simulation results suggest that Malaysian single carriageway roads have the capability to carry high flows without causing extensive traffic delays. The road layout and the presence of motorcycle have insignificant effect on maximum flow and journey speed. In contrast, the presence of HGVs proportion in the traffic stream has an influence on the maximum flow. The model also can be used to evaluate the effect of traffic directional split and priority junction on journey speed. The simulation results show a reduction in journey speed as the opposing flow increases. For a road section comprising of priority junctions, the number of junctions per kilometer length of the road has no influence on journey speed. The reduction in journey speed only occurs as the turning flow at the individual junction increases. This proposed a need for further field studies as the single carriageway roads speed/flow/geometry relationships do not include the journey speed being affected by both opposing flow and turning flow. There is also a need for further detailed of traffic operations field studies at or near capacity
Zeolite/polyaniline based self-healing and silicon oxide coatings for microbially induced corrosion inhibition
(Universiti Teknologi Malaysia, 2016) Saleh Ahdash, Abdelsalam Ibrahim
Microbially induced corrosion (MIC) occurs due to the presence of microorganisms such as bacteria, which form biofilms on the metal surface that can cause corrosion. Among the different methods that have been used to protect against MIC, coating has gained more attention because of its ease of application, low-cost and high effectiveness. Recent research has shown that self-healing coatings concept based on releasing healing agent when micro-cracks are initiated in the coating surface and hydrophobic silicon oxide based organic and inorganic coatings have great potential for use as antifouling coating. The aim of this research is to investigate the effects of self-healing and silicon oxide (SiO) coatings on inhibiting MIC in saline environment. The self-healing coating was prepared via interfacial polymerization of zeolite, polyaniline, and zeolite/polyaniline composite and then encapsulated with urea fomaldehyde as a shell material to form the microcapsules and embedded in epoxy to form coating material which was applied on mild steel substrate. The SiO coating, on the other hand, was deposited on mild steel substrate using radio frequency (RF) magnetron sputtering physical vapor deposition (PVD) method with different parameters of RF power, temperature, pressure and deposition time in order to achieve optimum parameters based on minimum surface roughness and good adhesion. The surface topography and roughness were examined by atomic force microscope (AFM), while the thickness and morphology of the coatings were observed using field emission scanning electron microscope (FESEM) equipped with energy dispersive spectrometer (EDS). The adhesion test was performed using nano scratch test for SiO coating and Pull off test for self-healing coating and supported by Rockwell C test. The corrosion behavior was investigated through salt spray test for 28 days and immersion tests in nutrient rich simulated seawater (NRSS) medium with pseudomonas aeruginosa bacteria for 70 days. The Tafel electrochemical test and electrochemical impedance spectroscopy (EIS) was performed on both bare and coated steel samples. AFM results clearly revealed that by varying the sputtering parameters has a strong influence on the surface roughness of the deposited SiO coating in which its thickness varied between 30 nm to 50 nm. The thickness for self-healing coating was between 50 μm to 175 μm. From the adhesion results, both coating methods produced superior adhesion on steel substrates. Fourier transform infrared spectroscopy (FTIR) results show the successful encapsulation of the three synthesized materials. The total self-healing occurred after the release of the core material when the capsule was ruptured after 21 days left at room temperature. The specimen exposed in salt spray chamber exhibited excellent corrosion resistance for all investigated coating materials, while, the specimens immersed in NRSS medium with pseudomonas aeruginosa bacteria showed varying anti-corrosion properties. Tafel results show that the lowest corrosion rate was observed for SiO coating with a value of 0.219 mm/yr, followed by encapsulated zeolite/polyaniline composite self-healing embedded in epoxy of 0.334 mm/yr. EIS results show that among all the coatings, encapsulated zeolite/polyaniline composite self-healing embedded in epoxy coating has the highest impedance modulus (Z) at a frequency of 0.01 of 7800 ohms. In conclusion, zeolite/polyaniline composite self-healing coating is the best among all the coating materials which shows superior anticorrosive and MIC inhibition property
Shear strength of steel fibre self-compacting concrete in precast concrete corbels
(Universiti Teknologi Malaysia, 2017) Lamide, Juli Asni
Self-compacting concrete (SCC) has been well known as an innovative concrete which requires zero mechanical vibration and being compacted solely under its own weight. Hardened SCC behaves similarly to the vibrated conventional normal concrete (NC). Normal concrete acts very brittle, thus, steel fibre self-compacting concrete (SFSCC) was formed by incorporating steel fibres into SCC. The objective of this study was to examine the effectiveness of SFSCC in the structural behaviour of precast concrete corbel to solve the reinforcement congestion problem caused by multiaxial forces in disturbed region by partially replacing the existing design reinforcement with steel fibre. Possible reduction of reinforcement in corbels was investigated using the optimised mix design of SFSCC, which developed in the early part of this study. 1.0% fibre volume fraction was selected as optimised mix of SFSCC for precast concrete corbel. A total of ten precast concrete corbels with three different concrete mixtures were cast and tested under vertical loading having different shear span-to-depth ratios and reinforcement configuration. Based on the experimental results, SFSCC showed improvements on the shear resistance, failure mechanisms and ductility behaviour of precast concrete corbels. The results also showed that up to 50% main reinforcement or shear reinforcement can be effectively replaced with the inclusion of 1.0% by volume of steel fibres. It has been noticed that the suggested semi-empirical equations which was developed based on strut-and-tie model (STM method) and shear-friction method produced good agreement due to its ability in giving the closest prediction and correlation with the experimental results. The calculation using STM method and shear-friction method registered (VExp/VCalc) ratio of about 0.96 and 1.03, respectively, with the corresponding standard deviation of about 0.07 and 0.03. Thus, it was concluded that the proposed semi-empirical equations were strongly recommended to be used in predicting the shear strength of precast concrete corbels made of SFSCC

Browse

Recent Submissions