Browsing by Author "Imteaz, M.A.,"

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Environmental Suitability and Carbon Footprint Savings of Recycled Tyre Crumbs for Road Applications
(Springer International Publishing, 2018) Imteaz, M.A.,; Arulrajah, A.,; Horpibulsuk, S.,; Ahsan, A.
With the aim of encouraging more waste diversions from traditional waste stockpiling and to reduce use of virgin materials in different engineering constructions, this paper presents the environmental suitability of reusing crushed used tyre instead of using virgin aggregate materials for road sub-base. Shredded tyre samples collected from a local recycling company in Melbourne were tested to evaluate any potential contaminant leaching from such material to the surrounding environment. Leaching tests were conducted for 100 potential contaminants following Australian Standard Leaching Procedure (ASLP) using three standard types of leaching solutions: acidic, neutral, and alkaline. From the series of leaching test results, it is clear that concentrations of all the assessed contaminants in the tested samples are either below their individual detection limits or below the Environmental Protection Authority (EPA) Victoria defined limits to label a material as hazardous. As such, in regards to leaching pollutants in the surrounding environment, tested crushed tyre samples are not hazardous and can be used for different engineering applications. Finally, a carbon footprint analysis was conducted considering a sustainable approach of using such crushed tyre with recycled concrete and recycled rock. It is found that through using such recycled materials carbon footprint savings per ton of road sub-base material would be 9.3 kg CO2e and 8.1 kg CO2e for using 2 and 3% tyre crumb, respectively.
Improved clogging and backwashing model for filtration of arsenic-contaminated water
(ICE Publishing, 2020-10-01) Imteaz, M.A.,; Ahsan, A.,; Kaur, P.
For many remote and under-privileged communities, water filtration is the first step of treatments before boiling and/or other higher level treatments. Clogging is a common unavoidable hindrance to such systems, which causes reduced efficiency with regard to the flow rate of filtered water. Backwashing is commonly used to recover the filtration capacity of clogged filter media. This paper presents an improvement of a previously developed simple clogging and backwashing efficiency model for the third-generation IHE family filter, which was developed by Unesco-IHE Institute for Water Education. The earlier simple model considered a linear decay of flow rate due to clogging in a weekly timestep. With the aim of enhancing the model's accuracy, this work considered three other models (a linear model with a daily timestep, a power function model and an exponential model). The performance of the models was assessed using the root mean squared error and chi-squared (χ2) values derived from predicted and measured flow rates through the device during successive clogging and backwashing periods for up to 4 months. The improvements using the linear 1 day model over the linear 7 day model were insignificant. Among the tested models, the power function model provided the best predictions, with an average χ2 improvement of 33% over the previously developed linear model.
Landfill leachate treatment by electrolysis and preparation of low cost activated carbon
(Nova Science Publishers, Inc., 2018-07-31) Erabee, I.K.,; Ahsan, A.,; Imteaz, M.A.,; Ng, A.W.M.
This study investigated the effects of different parameters on the removal efficiencies of organic and inorganic pollutants in landfill leachate treatment by electrolysis. Different parameters were considered such as the electric potential (e.g., 24, 40 and 60 V), hydraulic retention time (HRT) (e.g., 40, 60, 80, 100 and 120 min), sodium chloride (NaCl) concentration (e.g., 1, 3, 5 and 7%), pH (e.g., 3, 7 and 9), electrodes materials (e.g., aluminum (Al) and iron (Fe)) and distance between electrodes (e.g., 1, 2 and 3 cm). The best operational condition of electrolysis was then recommended. The electric potential of 60 V with HRT of 120 min at 5% of NaCl solution using Al as anode and Fe as cathode (kept at a distance of 3 cm) was the most efficient condition which increased the removal efficiencies of various parameters such as turbidity, salinity, total suspended solids (TSS), total dissolved solids (TDS), biochemical oxygen demand (BOD), chemical oxygen demand (COD) and heavy metals (e.g., Zn and Mn). The higher removal percentages of many parameters, especially COD (94%) and Mn (93%) indicated that the electrolysis is an efficient technique for multi-pollutants (e.g., organic, inorganic and heavy metals) removal from the landfill leachate. Two raw materials, sago palm bark (SPB) and date pits, were utilized as precursors to prepare high porosity activated carbon (AC). The porosity of these two raw materials was compared with that of commercial AC made from coconut shells. The physicochemical activation method was used for AC preparation, and it consisted of two steps, carbonization and activation. The activation process was performed using zinc chloride (ZnCl2) as an activation agent. N2 adsorption-desorption analysis was carried out to characterize the porosity of AC. Thermogravimetric analysis (TGA) was conducted for the two raw materials. The adsorbent made from SPB, which showed the maximum surface area of 1634 m2/g at the 700°C activation temperature for one hour, while the surface area of prepared AC from date pits was 1367 m2/g. Both prepared ACs had a larger surface area than commercial AC made with coconut shell (1348 m2/g).
Mathematical Modelling for Predicting Pollutant Removal Efficiencies of an Electrolysis System
(Springer, 2020) Imteaz, M.A.,; Ahsan, A.,; Kaur, P.,; Shanableh, A.
Electrolysis systems have been widely investigated for treating wastewater in laboratory-scale experiments, and most researchers reported efficient treatment outcomes. However, industrial scale implementation often necessitates assessing and prioritising various options involving different combinations of input parameters, which often requires mathematical models. This study presents mathematical models for predicting removal efficiencies of four different pollutants using electrolysis. Parametric equations were developed based on experimental results conducted in a previous study. Proposed equations are dependent on treatment retention time and current intensity (voltage). Results revealed that the experimental data followed consistent patterns, which lead to the derivations of generalised equations which were able to closely predict pollutants’ removal efficiencies obtained through experimental measurement. The developed equations also confirmed that beyond an optimum voltage, a further increase in voltage does not render higher removals of the pollutants, which is essential for enhancing the feasibility of industrial scale applications. © 2020, Springer Nature Switzerland AG.
Modifications of a simple clogging and back-washing efficiency model for arsenic filters
(ICE Publishing, 2019) Imteaz, M.A.,; Khan, S.A.,; Ahsan, A.
After continuous use of any filtration device, clogging of the filter media becomes apparent, which eventually causes poor performance of the filtration process. Back-washing is a common technique that is used for the recovery of the filtration capacity of clogged filter media. This paper presents the development of a simple clogging and back-washing efficiency model for a special filter medium. The 'third-generation IHE family filter' was developed by the Unesco-IHE Institute for Water Education and is widely used for treating arsenic-contaminated water in many countries, including Bangladesh. Several field tests were conducted at three different sites in Bangladesh having different qualities of influent water. The model coefficients developed were derived using the collected data on flow measurements through the device during successive clogging and back-washing periods of up to 4 months. The developed model with the selected model coefficients can simulate field measurements on flow retardation and recovery with good accuracy. Eventually, selected model coefficients (clogging factors) for the three sites were correlated with the respective ammonium and iron contents in the influent water. It was found that the clogging factor linearly varies with the ammonium and iron contents of the inflow water.
Solar panels: Real efficiencies, potential productions and payback periods for major Australian cities
(Elsevier Ltd, 2018-02-25) Imteaz, M.A.,; Ahsan, A.
In spite of continuous campaign and efforts large scale adoptions of solar panels are yet to be materialised, mainly due to lack of confidence on potential energy savings. This paper presents real efficiencies achieved from four houses in two Australian cities; Melbourne and Adelaide. Based on actual solar energy productions and actual incoming solar radiations during a monitoring period, efficiencies of solar panels installed in the selected houses were calculated. It was found that among the four monitored houses, a maximum efficiency of 7% was achieved. Considering this maximum achievable efficiency and annual average incoming solar radiations, potentials of energy savings for eight major cities of Australia are presented considering two different solar panel systems; 2 kW and 5 kW. It was found that for a typical 4-members household winter-demand, a 2 kW system and 5 kW system is expected to generate 19–29% and 49–73% of total energy. In addition, considering the current costs and expected savings, payback periods of different sized solar systems are presented for the eight cities.
SwinOSD: A computer tool for designing onsite detention basin
(Inderscience Publishers, 2021) Imteaz, M.A.,; Hossain, I.,; Ahsan, A.,
A computer tool was developed to calculate sizing requirements of onsite detention (OSD) basins. The tool reads design rainfall and temporal pattern from pre-populated spreadsheets, which are linked with the tool. The tool calculates OSD storage required from the calculated runoff time-series (for a particular time period) and user-provided permissible site discharge (PSD). The tool also calculates maximum storage required considering worst temporal pattern of rainfall for a conservative design. It also calculates average storage volume required taking averages of calculated storages based on all the temporal patterns. Eventually, for a selected water height, the tool calculates required orifice diameter to maintain a given PSD. The tool calculated storage requirements were compared with the widely used urban drainage model, DRAINS. For all the selected scenarios, the DRAINS simulated storage-depth curves show that the developed tool calculated results are compatible with DRAINS calculations under the same scenario.