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Nga Pham

Research Assistant, School of Civil and Environmental Engineering
 

Journal articles

Pham, T.T.N., Mainali, B., Ngo, H.H., Guo, W., Listowski, A., O'Halloran, K., Miechel, C. & Corby, N. 2015, 'Effect of heavy metals in recycled water used for household laundry on quality of cloth and washing machine', DESALINATION AND WATER TREATMENT, vol. 54, no. 1, pp. 178-190.
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Nguyen, T., Logananthan, P., Tien Vinh, N., Thi TN, P., Jaya, K., Wu, M., Naidu, R. & Vigneswaran, S. 2015, 'Trace elements in road-deposited and water bed sediments in Kogarah Bay of Sydney, Australia: Enrichment, sources, and fractionation', Soil Research.
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Road-deposited sediments (RDS) are a potential source of trace elements (TE) that can be transported by stormwater to neighbouring water bodies and cause aquatic pollution. A study in Sydney, Australia showed that of the 11 TE analysed, Zn, Cu, V, Cr, and Sb were greatly enriched in RDS compared to those in baseline soils (BS). All TE concentrations in water bed-sediments (WBS) in the catchment area were similar to those in the BS. Correlation and principal component analyses revealed that of the five TE enriched in RDS, Zn, Cu, Cr and Sb were related to each other, and they probably originated from vehicle components such as tyres and brake linings. Vanadium was separated into another component, likely to have originated mainly from road surface asphalt abrasion. Trace element concentrations in the mobile fraction of RDS, determined using a sequential extraction method, were: Fe >Mn, Zn > Cu, Pb> Cr, Ni, V, Cd, Sb. However, this fraction as a percentage of total elemental concentration was highest for Cd and Zn and lowest for Fe, Cr, Ni, and V. The RDS sites had low-medium ecological risk whereas WBS and BS sites had low risk.
Mainali, B., Pham, N., Ngo, H., Guo, W., Listowski, A., O'Halloran, K., Miechel, C., Muthukaruppan, M. & Johnston, R.R. 2014, 'Introduction and feasibility assessment of laundry use of recycled water in dual reticulation systems in Australia', The Science of the Total Environment, vol. 470-471, pp. 34-43.
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Laundry is a potential new end use of recycled water in dual reticulation systems. Generally, the community is willing to accept this new end use if it can meet the concerns on health issues, durability of washing machine, cloth quality and aesthetic appearance. This study addresses all these major concerns thereby assisting in the introduction and promotion of this new end use in the existing and proposed dual reticulation systems. Five representative cloth materials were selected for washing in tap water and in recycled water for up to 50 wash cycles for comparative studies. The tearing/tensile strength tests were used for the assessment of cloth durability. ANOVA one way test was applied for the significance analysis (Tukey's test p b 0.05) which indicated that there is no significant change in the tensile/tearing strengths of washed cloth samples. Scanning electron microscope (SEM) images of the washed cloth samples found no distinct change in surface morphology. Textile colour analysis (CIEDE2000) analysed the variation in colour of the washed cloth samples and showed that the change in colour ?E ranges from 01 revealing no visible difference in colour of cloth samples. Langelier Saturation Index (LSI) was used as the indicator for predicting corrosive/scaling potential of recycled water. The LSI values ranged from +0.5 to -0.5, indicating no corrosive or scaling potential of recycled water. The microbiological study of the cloth samples washed in recycled water indicated that there was no contamination with representative bacteria. As the recycled water has similar effects like tap water on cloth and washing machine, it is safe to use for laundry.
Chen, Z., Ngo, H., Guo, W., Pham, N., Lim, R.P., Wang, X.C., Miechel, C., O'Halloran, K., Listowski, A. & Corby, N. 2014, 'A new optional recycled water pre-treatment system prior to use in the household laundry', The Science of the Total Environment, vol. 476-447, pp. 513-521.
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With a constantly growing population, water scarcity becomes the limiting factor for further social and economic growth. To achieve a partial reduction in current freshwater demands and lessen the environmental loadings, an increasing trend in the water market tends to adopt recycled water for household laundries as a new recycled water application. The installation of a small pre-treatment unit for water purification can not only further improve the recycled water quality, but also be viable to enhance the public confidence and acceptance level on recycled water consumption. Specifically, this paper describes column experiments conducted using a 550 mm length bed of zeolite media as a one-dimensional flow reactor. The results show that the zeolite filter system could be a simple low-cost pre-treatment option which is able to significantly reduce the total hardness level of recycled water via effective ion exchange. Additionally, depending on the quality of recycled water required by end users, a new by-pass controller using a three-level operation switching mechanism is introduced. This approach provides householders sufficient flexibility to respond to different levels of desired recycled water quality and increase the reliability of long-term system operation. These findings could be beneficial to the smooth implementation of new end uses and expansion of the potential recycled water market. The information could also offer sound suggestions for future research on sustainable water management and governance.
Nguyen, T.V., Jeong, S., Pham, T.T.N., Kandasamy, J. & Vigneswaran, S. 2014, 'Effect of granular activated carbon filter on the subsequent flocculation in seawater treatment', Desalination, vol. 354, pp. 9-16.
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Nguyen, T.V., Loganathan, P., Vigneswaran, S., Krupanidhi, S., Pham, T.T.N. & Ngo, H.-.H. 2014, 'Arsenic waste from water treatment systems: characteristics, treatments and its disposal', Water Science and Technology-Water Supply, vol. 14, no. 6, pp. 939-950.
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Mainali, B., Pham, N., Ngo, H. & Guo, W. 2013, 'Maximum allowable values of the heavy metals in recycled water for household laundry', Science of the Total Environment, vol. 452-453, no. 1, pp. 427-432.
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Household laundry as a new end use of recycled water in dual reticulation systems has a great potential as the significant amount of potablewater fromurban households can be saved. However, there is still no sufficient evidence and supporting recycledwater quality guidelines for this particular use. A key gap in knowledge is the impact of heavymetals in recycledwater on clothes and washingmachines. Thus, this study aims to determine the maximumallowable values (MAVs) of the heavy metals iron (Fe), lead (Pb), zinc (Zn), copper (Cu), andmanganese (Mn) in recycled water for washing clothes in washing machines. Six different concentrations of each targeted metals were prepared in tap water for the washing machine experiments. The tearing/tensile strength tests were used for the assessment of cloth durability.MINITAB 16 as a statistical tool was used and ANOVA one way testwas applied for the significance analysis (Turkey's test p b 0.05). The results show that theMAVs of the heavy metals Fe, Pb, Zn, Cu and Mn were found to be 1 mg/l, 1 mg/l, 10 mg/l, 5 mg/l and 1 mg/l respectively in terms of cloth durability.
Mainali, B., Pham, N., Ngo, H., Guo, W., Miechel, C., O'Halloran, K., Muthukaruppan, M. & Listowski, A. 2013, 'Vision and perception of community on the use of recycled water for household laundry: A case study in Australia', Science of the Total Environment, vol. 463-464, no. 1, pp. 657-666.
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This study investigates the community perception of household laundry as a new end use of recycled water in three different locations of Australia through a face to face questionnaire survey (n = 478). The study areas were selected based on three categories of (1) non-user, (2) perspective user and (3) current user of recycled water. The survey results indicate that significantly higher number (70%) of the respondents supported the use of recycled water for washing machines (?2 = 527.40, df = 3; p = 0.000). Significant positive correlation between the overall support for the new end use and the willingness of the respondents to use recycled water for washing machine was observed among all users groups (r = 0.43, p = 0.000). However, they had major concerns regarding the effects of recycled water on the aesthetic appearance of cloth, cloth durability, machine durability, odour of the recycled water and cost along with the health issues. The perspective user group had comparatively more reservations and concerns about the effects of recycled water on washing machines than the non-users and the current users (?2 = 52.73, df = 6; p = 0.000). Overall, community from all three study areas are willing towelcome this new end use as long as all their major concerns are addressed and safety is assured.
Pham, N., Ngo, H., Guo, W., Ho, D., Mainali, B., Johnston, A.J. & Listowski, A. 2011, 'Responses of community to the possible use of recycled water for washing machines: A case study in Sydney, Australia', Resources, Conservation and Recycling, vol. 55, no. 5, pp. 535-540.
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Recycled water is a valuable resource that has potential to free up potable water supplies and recharge systems while improving the environment. Recycled water for washing machine could be one of the options as new end use of recycled water to alleviate the demand on existing and limited water supplies. This paper summarizes the findings of a research survey in Sydney, Australia to explore the attitudes and opinions of community towards the use of recycled water for different purposes, especially for the washing machine. The survey showed that 97% of the respondents were aware of the persisting water shortage problem while more than 60% of the respondents supported the use of recycled water for washing clothes. This paper exposes the basic concern of participants for using recycled water in washing machine. Health issue was found as the most concerns of the community. The survey also presents the further conditions to be considered for using recycled water for washing machine according to the participants' opinions. Correlation between knowledge and attitudes of respondents was also found in this survey.
Mainali, B., Ngo, H., Guo, W., Pham, N., Wang, X.C. & Johnston, A.J. 2011, 'SWOT analysis to assist identification of the critical factors for the successful implementation of water reuse schemes', Desalination and Water Treatment, vol. 32, pp. 297-306.
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The reuse of urban wastewater has been recognised as an important alternative source of water and is a key aspect of sustainable water policy. As it is a promising innovation, a number of direct and indirect water reuse projects have been instigated and proposed, both nationally and internationally. However there is some uncertainty regarding the effectiveness and impact of these water reuse schemes (WRS). This study investigates the applicability of Strengths, Weaknesses, Opportunities, and Threats (SWOT) as an analysis tool for formulating the critical factors in terms of the implementation of water reuse schemes. Basically, this work adopts an existing multiple case study design method and makes use of SWOT to analyse all critical factors for each selected water reuse scheme. The strengths and weaknesses of successful and unsuccessful WRS are analysed followed by an assessment of the corresponding external opportunities and threats.. On this basis, the critical factors considered for the successful implementation of the WRS are identified. A qualitative investigation using SWOT analysis has therefore been successfully implemented.
Mainali, B., Ngo, H., Guo, W., Pham, N. & Johnston, A.J. 2011, 'Feasibility assessment of recycled water use for washing machines in Australia through SWOT analysis', Resources, Conservation and Recycling, vol. 56, no. 1, pp. 87-91.
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Sustainable urban water consumption has become a critical issue in Australia due to increasing urbanization, the countryâs dry climate and its increasingly variable rainfall. Water recycling is considered vital to alleviate the demand on limited water supplies. The demands on water utilities to develop water recycling capacity and supplies are therefore expected to intensify in Australia. Dual reticulation systems have already been introduced in many cities in Australia and this is likely to expand to many other cities in the future. Developed and proposed dual reticulation schemes in Australia demand the substantial replacement of tap water with recycled water to ensure system optimisation and the sustainability of water supplies. This study successfully applies Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis as a research tool to assess the feasibility of use of recycled water in washing machine applications. Through the identification of the reuse schemes' strengths (elements to leverage and build on) and weaknesses (areas to seek assistance and support) in addition to community opportunities (areas to leverage for program advantages) and threats (elements that could hinder the scheme), the positive aspects for the use of recycled water in washing machines is observed. Further study to address the specific concerns of the general public and the development of guidelines for this new end use is however essential to guide the implementation of recycled water schemes.
Ngo, H., Chuang, Y., Guo, W., Ho, D., Pham, N., Johnston, A.J., Lim, R.P. & Listowski, A. 2009, 'Resident's strategy survey on a new end use of recycled water in Australia', Desalination and Water Treatment, vol. 11, no. 1-3, pp. 93-97.
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The concept of using recycled water for washing machine was introduced as a new end use. As there is a noticeable lack social research in understanding the general public perceptions of this application, the residents strategy survey was carried out at some selective suburbs in Sydney with demographically based signifi cant differences of general, gender, age, education, and property style and ownership. The survey indicates that the majority in the community considers the use of recycled water for washing machine is indispensable in view of continuing drought and the associated water shortages. Given safety assurance and demonstration, recycled water for washing machine has a considerable proportion within the responses. The general level of knowledge in community clearly understand that recycled water is more environmentally friendly option, whereas from cleanness and public health point of view, higher quality water is required to be reused in washing machine. Moreover, the residents reckon to have a small unit for pre-treatment (point of use) before recycled water entering washing machines might assure the quality and safety. The survey also shows the major concerns for a resident to use recycled water for washing machine are public health, water cleanness and washing machine durability.
Pham, N., Buckney, R.T. & Pulkownik, A. 2007, 'Metal speciation in sediment in West Lake (Ho Tay), Hanoi, Vietnam', International Journal of Water, vol. 3, no. 4, pp. 356-367.
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The speciation patterns of Cd, Cr, Cu, Mn, Pb and Zn in 24 sediment samples from West Lake, Vietnam were investigated using a sequential extraction scheme modified from Tessier et al. The results indicated that only a very small portion of the total metal was easily available (found in the exchangeable (<5%) and carbonate (<15%) fractions for all metals except Mn). Stably bound metals account for the major amounts (25-47%) of Cr, Cu, Pb and Zn. The sequential extraction is useful to indirectly assess the potential mobility and bioavailability of the heavy metals in the sediment. The mobility of these metals is related to their solubility and geochemical forms, and it decreases in the order: Mn > Cd > Zn > Pb > Cr > Cu. Significant correlations among all extracted fractions for all six metals were observed. The number of correlations between any two metal binding fractions suggests that they might be discharged from the same pollution source.