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Opportunities exist for forestry companies to vertically integrate operations to include both forest estate management and timber processing. However, forest supply chains have traditionally functioned in a decoupled manner where forest operations and timber processing are uncoordinated in their planning and operation, leading to sub-optimal supply chain configuration and outcomes. To maximize the benefits of vertically integrated forest supply chains, the planning method needs to include both strategic and tactical decisions simultaneously. This paper demonstrates a mixed integer linear programming integrated forest planning model that integrates strategic level forest management on a long 40-year planning horizon with sawmill operations in the tactical level decision over multiple shorter horizons with the 40 year overall planning period to cover the decisions related to forest and the wood processing plant. The results show that when compared to uncoordinated forestry and processing model outcomes, the incorporation of forestry and processing operations in an integrated optimization model can increase the NPV of the combined enterprise over 20%. The results are tested to a range of sensitivities, including discount rate, harvest cost and harvest volume. The revenue from selling processed wood products made possible when a forest management firm owns its own timber mill accounts for the integrated model profitability increase, which is not available in the strategic model representing a forest firm without timber processing capacity. The results emphasize that the integrated planning method could bring more economic returns and support forest managers' decision-making.
Li Luo; Jim O'Hehir; Courtney M. Regan; Li Meng; Jeffery D. Connor; Christopher W.K. Chow. An integrated strategic and tactical optimization model for forest supply chain planning. Forest Policy and Economics 2021, 131, 102571 .
AMA StyleLi Luo, Jim O'Hehir, Courtney M. Regan, Li Meng, Jeffery D. Connor, Christopher W.K. Chow. An integrated strategic and tactical optimization model for forest supply chain planning. Forest Policy and Economics. 2021; 131 ():102571.
Chicago/Turabian StyleLi Luo; Jim O'Hehir; Courtney M. Regan; Li Meng; Jeffery D. Connor; Christopher W.K. Chow. 2021. "An integrated strategic and tactical optimization model for forest supply chain planning." Forest Policy and Economics 131, no. : 102571.
Pumping stations in a wastewater network use predetermined high and low sump elevations to manage overflow and spills of the system, but the operation protocol, generally, does not consider energy costs related to pumps. For wastewater pumping, the largest segment of the operating cost is spent on electricity charges. Therefore, management of electricity use in wastewater operations is crucial. The purpose of this study is to develop a tool to assist asset operators to reduce electricity costs by improving and optimizing the pump control switching. With the consideration of the wholesale electricity prices from the spot market, there is an opportunity to improve efficiency and save costs by intelligent and smart scheduling control. A novel concept of utilizing the existing wastewater network hydraulic model to simulate the operations of the pump controller was undertaken. The sump elevation/wet well level and electricity spot prices were used as the two inputs of the smart controller to operate the pumps. Simulated results show that this smart controller could be a practical solution in terms of energy optimization and cost reduction to improve conventional pump switching models with up to 13% savings across the entire network under different dry and wet weather flow conditions.
Phuong Do; Neda Gorjian Jolfaei; Nima Gorjian; Leon van der Linden; Faisal Ahammed; Raufdeen Rameezdeen; Bo Jin; Christopher W. K. Chow. Smart Scheduling of Pump Control in Wastewater Networks Based on Electricity Spot Market Prices. Water Conservation Science and Engineering 2021, 6, 79 -94.
AMA StylePhuong Do, Neda Gorjian Jolfaei, Nima Gorjian, Leon van der Linden, Faisal Ahammed, Raufdeen Rameezdeen, Bo Jin, Christopher W. K. Chow. Smart Scheduling of Pump Control in Wastewater Networks Based on Electricity Spot Market Prices. Water Conservation Science and Engineering. 2021; 6 (2):79-94.
Chicago/Turabian StylePhuong Do; Neda Gorjian Jolfaei; Nima Gorjian; Leon van der Linden; Faisal Ahammed; Raufdeen Rameezdeen; Bo Jin; Christopher W. K. Chow. 2021. "Smart Scheduling of Pump Control in Wastewater Networks Based on Electricity Spot Market Prices." Water Conservation Science and Engineering 6, no. 2: 79-94.
Protein, the main component of extracellular polymeric substances, plays a vital role in sediment dewatering. Tannic acid (TA) can bind with protein, so was used as a new conditioner for sediment dewatering. The benefit of using TA as a conditioner for sediment dewatering and its mechanism were explored in this study. A series of laboratory-based experiments were conducted and the water content (Wc) of sediment cakes, specific resistance to filtration (SRF) and the filterable dehydration rate were used to evaluate the sediment dewaterability. The results showed that at the optimal dosage of 0.20 mmol/gTS (total solid), TA reduced Wc of sediment cakes by 12.3% and SRF by 70.6%, and increased the filterable dehydration rate by 9%. These results indicated TA effectively improved the dewatering performance of sediment. The conditioning mechanism study of TA supported that the protein content was reduced by combining with TA, and the bound water was gradually converted into free water. When TA was added in sufficient amount, the particle size gradually increased, large and dense aggregates were formed which enhanced the dewatering performance of the sediment. These results confirm the feasibility of using TA as an effective option for rapid dewatering of sediment and provide a reference for selecting the appropriate conditioner for sediment dewatering.
Qunshan Wei; Xiaojing Liu; Yanxia Zhang; Kai Zhang; Zheng Li; Zhemin Shen; Christopher W.K. Chow. Effect of tannic acid on the dewaterability of dredged sediment and the conditioning mechanism. Journal of Environmental Chemical Engineering 2020, 9, 104899 .
AMA StyleQunshan Wei, Xiaojing Liu, Yanxia Zhang, Kai Zhang, Zheng Li, Zhemin Shen, Christopher W.K. Chow. Effect of tannic acid on the dewaterability of dredged sediment and the conditioning mechanism. Journal of Environmental Chemical Engineering. 2020; 9 (1):104899.
Chicago/Turabian StyleQunshan Wei; Xiaojing Liu; Yanxia Zhang; Kai Zhang; Zheng Li; Zhemin Shen; Christopher W.K. Chow. 2020. "Effect of tannic acid on the dewaterability of dredged sediment and the conditioning mechanism." Journal of Environmental Chemical Engineering 9, no. 1: 104899.
The spectra fingerprint of drinking water from a water treatment plant (WTP) is characterised by a number of light-absorbing substances, including organic, nitrate, disinfectant, and particle or turbidity. Detection of disinfectant (monochloramine) can be better achieved by separating its spectra from the combined spectra. In this paper, two major focuses are (i) the separation of monochloramine spectra from the combined spectra and (ii) assessment of the application of the machine learning algorithm in real-time detection of monochloramine. The support vector regression (SVR) model was developed using multi-wavelength ultraviolet-visible (UV-Vis) absorbance spectra and online amperometric monochloramine residual measurement data. The performance of the SVR model was evaluated by using four different kernel functions. Results show that (i) particles or turbidity in water have a significant effect on UV-Vis spectral measurement and improved modelling accuracy is achieved by using particle compensated spectra; (ii) modelling performance is further improved by compensating the spectra for natural organic matter (NOM) and nitrate (NO3) and (iii) the choice of kernel functions greatly affected the SVR performance, especially the radial basis function (RBF) appears to be the highest performing kernel function. The outcomes of this research suggest that disinfectant residual (monochloramine) can be measured in real time using the SVR algorithm with a precision level of ± 0.1 mg L−1.
Sharif Hossain; Christopher W.K. Chow; Guna A. Hewa; David Cook; Martin Harris. Spectrophotometric Online Detection of Drinking Water Disinfectant: A Machine Learning Approach. Sensors 2020, 20, 6671 .
AMA StyleSharif Hossain, Christopher W.K. Chow, Guna A. Hewa, David Cook, Martin Harris. Spectrophotometric Online Detection of Drinking Water Disinfectant: A Machine Learning Approach. Sensors. 2020; 20 (22):6671.
Chicago/Turabian StyleSharif Hossain; Christopher W.K. Chow; Guna A. Hewa; David Cook; Martin Harris. 2020. "Spectrophotometric Online Detection of Drinking Water Disinfectant: A Machine Learning Approach." Sensors 20, no. 22: 6671.
Alkali–silica reaction (ASR) attack is one of the most significant durability concerns in cement-based materials. In this paper, the drinking water treatment sludge (DWTS), which is a typical by-product from the drinking water treatment industry, was reused as supplementary cementitious material to mitigate the degradation of mortar resulting from ASR attack. DWTS was milled and calcined at 800 °C for 2 h before being used as a replacement for cement. Glass sand was used as the reactive fine aggregate. Properties of four mortar mixtures prepared with 0%, 5%, 10%, and 20% of calcined DWTS replacement of cement were firstly assessed, including compressive strength, flexural strength, and water sorptivity. The mortar specimens were then exposed to an ASR-attacked environment for 28 days, the changes in specimen length were monitored, and the uniformity of mortar was measured via Ultrasonic pulse velocity (UPV). The results showed that 10% replacement significantly improved the mechanical properties of mortar. The specimens with 20% of the calcined DWTS exhibited comparable strength relative to the reference group and exhibited superior resistance to ASR attack. Additionally, a water sorptivity test showed that higher contents of the calcined DWTS can lead to lower water capillary absorption of mortar.
Weiwei Duan; Yan Zhuge; Phuong Ngoc Pham; Christopher W. K. Chow; Alexandra Keegan; Yue Liu. Utilization of Drinking Water Treatment Sludge as Cement Replacement to Mitigate Alkali–Silica Reaction in Cement Composites. Journal of Composites Science 2020, 4, 171 .
AMA StyleWeiwei Duan, Yan Zhuge, Phuong Ngoc Pham, Christopher W. K. Chow, Alexandra Keegan, Yue Liu. Utilization of Drinking Water Treatment Sludge as Cement Replacement to Mitigate Alkali–Silica Reaction in Cement Composites. Journal of Composites Science. 2020; 4 (4):171.
Chicago/Turabian StyleWeiwei Duan; Yan Zhuge; Phuong Ngoc Pham; Christopher W. K. Chow; Alexandra Keegan; Yue Liu. 2020. "Utilization of Drinking Water Treatment Sludge as Cement Replacement to Mitigate Alkali–Silica Reaction in Cement Composites." Journal of Composites Science 4, no. 4: 171.
There is an increasing need to use online instrumentation for continuous monitoring of water quality. However, industrial applications using online instruments, such as submersible UV-Vis spectrophotometers, may require the use of alternative techniques to remove particle effect rather than performing a physical filtration step. Some submersible UV-Vis spectrophotometers have built-in generic particle compensation algorithms to remove the filtration step. This work studied the influence of suspended particles on the measurements of a submersible UV-Vis spectrophotometer as well as the performance of the built-in particle compensation technique under laboratory-controlled conditions. Simulated water samples were used in the combinations of standard particles from laboratory chemical and natural particles extracted from water systems with ultrapure water and treated water from a drinking water treatment plant. Particle contributions to the UV absorbance at 254 nm (UV254) measurements of water samples varied differently when particle types or concentrations changed. The compensated UV254, measured by the submersible instrument using the built-in generic particle compensation algorithms, was compared with laboratory UV254, analysed by the bench-top instrument with the physical filtration method. The results indicated that the built-in generic compensation algorithms of the submersible UV-Vis spectrophotometer may generate undercompensated UV254 or overcompensated UV254 for various surface waters. These findings provide in-depth knowledge about the impact of suspended particles on the measurements of submersible UV-Vis spectrophotometers; source water dependence; and why site-specific calibration is often needed to get accurate measurements.
Zhining Shi; Christopher W. K. Chow; Rolando Fabris; Tianlong Zheng; Jixue Liu; Bo Jin. Evaluation of the impact of suspended particles on the UV absorbance at 254 nm (UV254) measurements using a submersible UV-Vis spectrophotometer. Environmental Science and Pollution Research 2020, 28, 12576 -12586.
AMA StyleZhining Shi, Christopher W. K. Chow, Rolando Fabris, Tianlong Zheng, Jixue Liu, Bo Jin. Evaluation of the impact of suspended particles on the UV absorbance at 254 nm (UV254) measurements using a submersible UV-Vis spectrophotometer. Environmental Science and Pollution Research. 2020; 28 (10):12576-12586.
Chicago/Turabian StyleZhining Shi; Christopher W. K. Chow; Rolando Fabris; Tianlong Zheng; Jixue Liu; Bo Jin. 2020. "Evaluation of the impact of suspended particles on the UV absorbance at 254 nm (UV254) measurements using a submersible UV-Vis spectrophotometer." Environmental Science and Pollution Research 28, no. 10: 12576-12586.
The present study provides a proof-of-concept data collection methodology for water pipes failure from publicly available (open) data sources and identification of the common causes of water pipes failure in a water supply network, which may be automated with artificial intelligent (AI) methodology. Using Adelaide (South Australia) as the location of our case study, open source databases, such as pipe failures of SA Water (Twitter feeds), data from the Bureau of Meteorology, Adelaide Metropolitan soil data reports, etc., have been used to identify pipe failure locations, which was then correlated with the environmental factors e.g. soil type, monthly rainfall pattern, etc. The results were compared with the SA Water’s renewal program to validate the methodology introduced by this research. The results confirmed SA Water’s asset management system is very effective in managing its linear assets with the areas focused on the water main replacement program matched well with the pipe failure locations. This not only validated the methodology introduced by this research is capable to identify the high-risk pipe failure areas but also facilitated linkage between government and public agencies externally via their open access data which may complement their core services.
Nazila Hekmati; Mizanur Rahman; Nima Gorjian; Rameez Rameezdeen; Christopher W. K. Chow. Relationship between environmental factors and water pipe failure: an open access data study. SN Applied Sciences 2020, 2, 1 -12.
AMA StyleNazila Hekmati, Mizanur Rahman, Nima Gorjian, Rameez Rameezdeen, Christopher W. K. Chow. Relationship between environmental factors and water pipe failure: an open access data study. SN Applied Sciences. 2020; 2 (11):1-12.
Chicago/Turabian StyleNazila Hekmati; Mizanur Rahman; Nima Gorjian; Rameez Rameezdeen; Christopher W. K. Chow. 2020. "Relationship between environmental factors and water pipe failure: an open access data study." SN Applied Sciences 2, no. 11: 1-12.
Concrete wastewater infrastructures are important to modern society but are susceptible to sulfuric acid attack when exposed to an aggressive environment. Fibre-reinforced mortar has been adopted as a promising coating and lining material for degraded reinforced concrete structures due to its unique crack control and excellent anti-corrosion ability. This paper aims to evaluate the performance of polyethylene (PE) fibre-reinforced calcium aluminate cement (CAC)–ground granulated blast furnace slag (GGBFS) blended strain-hardening mortar after sulfuric acid immersion, which represented the aggressive sewer environment. Specimens were exposed to 3% sulfuric acid solution for up to 112 days. Visual, physical and mechanical performance such as water absorption ability, sorptivity, compressive and direct tensile strength were evaluated before and after sulfuric acid attack. In addition, micro-structure changes to the samples after sulfuric acid attack were also assessed by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) to further understand the deterioration mechanism. The results show that overall fibre-reinforced calcium aluminate cement (CAC)-based samples performed significantly better than fibre-reinforced ordinary Portland cement (OPC)-based samples as well as mortar samples in sulfuric acid solution in regard to visual observations, penetration depth, direct tensile strength and compressive reduction. Gypsum generation in the cementitious matrix of both CAC and OPC-based systems was the main reason behind the deterioration mechanism after acid attack exposure. Moreover, laboratory sulfuric acid testing has been proven for successfully screening the cementitious material against an acidic environment. This method can be considered to design the service life of concrete wastewater pipes.
Wei Fan; Yan Zhuge; Xing Ma; Christopher W. K. Chow; Nima Gorjian; Jeong-A Oh; Weiwei Duan. Durability of Fibre-Reinforced Calcium Aluminate Cement (CAC)–Ground Granulated Blast Furnace Slag (GGBFS) Blended Mortar after Sulfuric Acid Attack. Materials 2020, 13, 3822 .
AMA StyleWei Fan, Yan Zhuge, Xing Ma, Christopher W. K. Chow, Nima Gorjian, Jeong-A Oh, Weiwei Duan. Durability of Fibre-Reinforced Calcium Aluminate Cement (CAC)–Ground Granulated Blast Furnace Slag (GGBFS) Blended Mortar after Sulfuric Acid Attack. Materials. 2020; 13 (17):3822.
Chicago/Turabian StyleWei Fan; Yan Zhuge; Xing Ma; Christopher W. K. Chow; Nima Gorjian; Jeong-A Oh; Weiwei Duan. 2020. "Durability of Fibre-Reinforced Calcium Aluminate Cement (CAC)–Ground Granulated Blast Furnace Slag (GGBFS) Blended Mortar after Sulfuric Acid Attack." Materials 13, no. 17: 3822.
Particles in the water can significantly affect UV–Vis absorption measurements. There is a need for the water industry to develop a reliable technique to eliminate particle impact on on-line water quality monitoring using UV–Vis spectroscopy. This study aims to develop and use digital techniques for particle compensation: single wavelength compensation, linear regression compensation and multiplicative scatter correction method for on-line UV–Vis spectrophotometers. Water quality data were collected from three selected water sources in water treatment plants which represent different water qualities in terms of particles and organic matters. UV254 measurements were determined with these three software compensation techniques in comparison with the proprietary instrument built-in compensation algorithm using Bland-Altman analysis. Linear correction methods were found to be able to adjust the three compensation techniques to achieve acceptable compensated UV254 results, particularly for raw waters. UV254 measurements using single wavelength compensation, linear regression compensation and multiplicative scatter correction techniques with the assistant of linear correction methods were confirmed to be comparable to the instrument built-in compensation method. Our results reveal that these particle compensation techniques can make the UV254 technology reliable for online water quality monitoring in water treatment network. This paper demonstrated the advantage of using software compensation method to establish local compensation and calibration models instead of relying on the predetermined global calibrations for online water quality monitoring.
Zhining Shi; Christopher W.K. Chow; Rolando Fabris; Jixue Liu; Bo Jin. Alternative particle compensation techniques for online water quality monitoring using UV–Vis spectrophotometer. Chemometrics and Intelligent Laboratory Systems 2020, 204, 104074 .
AMA StyleZhining Shi, Christopher W.K. Chow, Rolando Fabris, Jixue Liu, Bo Jin. Alternative particle compensation techniques for online water quality monitoring using UV–Vis spectrophotometer. Chemometrics and Intelligent Laboratory Systems. 2020; 204 ():104074.
Chicago/Turabian StyleZhining Shi; Christopher W.K. Chow; Rolando Fabris; Jixue Liu; Bo Jin. 2020. "Alternative particle compensation techniques for online water quality monitoring using UV–Vis spectrophotometer." Chemometrics and Intelligent Laboratory Systems 204, no. : 104074.
Catherine E. Dandie; Abiodun D. Ogunniyi; Sergio Ferro; Barbara Hall; Barbara Drigo; Christopher W. K. Chow; Henrietta Venter; Baden Myers; Permal Deo; Erica Donner; Enzo Lombi. Disinfection options for irrigation water: Reducing the risk of fresh produce contamination with human pathogens. Critical Reviews in Environmental Science and Technology 2019, 50, 2144 -2174.
AMA StyleCatherine E. Dandie, Abiodun D. Ogunniyi, Sergio Ferro, Barbara Hall, Barbara Drigo, Christopher W. K. Chow, Henrietta Venter, Baden Myers, Permal Deo, Erica Donner, Enzo Lombi. Disinfection options for irrigation water: Reducing the risk of fresh produce contamination with human pathogens. Critical Reviews in Environmental Science and Technology. 2019; 50 (20):2144-2174.
Chicago/Turabian StyleCatherine E. Dandie; Abiodun D. Ogunniyi; Sergio Ferro; Barbara Hall; Barbara Drigo; Christopher W. K. Chow; Henrietta Venter; Baden Myers; Permal Deo; Erica Donner; Enzo Lombi. 2019. "Disinfection options for irrigation water: Reducing the risk of fresh produce contamination with human pathogens." Critical Reviews in Environmental Science and Technology 50, no. 20: 2144-2174.
Monitoring low levels of ammonia in chloraminated water can be challenging but is important for effectively managing potable water disinfection. The lower the concentration of free ammonia that can be determined, the tighter the control at the disinfection point, which supports better maintenance of chloramine residuals in the distribution system. In this study a micro-distillation technique was used to selectively separate ammonia into a boric acid solution allowing determination by conductance (i.e., micro-distillation and conductance measurement instrument - Micro-DCMI). The optimised technique had a linear calibration range of 0.01 to 60 mg NH3 L−1 with a limit of detection (LOD) of 0.014 mg L−1 and limit of quantification (LOQ) of 0.045 mg L−1. With the optimum operational parameters of 80 °C distillation temperature, 0.3 L min−1 air flow rate, 0.1 mol L−1 boric acid concentration and 8 minutes pre-concentration time, a sample throughput of 7 samples per hour was achieved. A1 laboratory comparison between Micro-DCMI and the standard ammonia selective electrode method was conducted on water samples obtained from a chloraminated drinking water distribution system. The results showed that the ratios of the free ammonia values determined by Micro-DCMI and an ammonia selective electrode were between 0.82 and 1.2 for 11 water samples. A custom-built automated analytical system was evaluated at a water treatment plant in Australia and the results compared favourably with the in plant online ammonia ion selective analyser. This study indicated that the Micro-DCMI method is a simple, robust and low cost online monitoring system suitable for determining low concentration ammonia to manage chloramination.
Jianyin Huang; Christopher W.K. Chow; Philipp Kuntke; Lise Cruveiller; Gregory Gnos; David E. Davey; Peter Teasdale. The development and evaluation of a microstill with conductance detection for low level ammonia monitoring in chloraminated water. Talanta 2019, 200, 256 -262.
AMA StyleJianyin Huang, Christopher W.K. Chow, Philipp Kuntke, Lise Cruveiller, Gregory Gnos, David E. Davey, Peter Teasdale. The development and evaluation of a microstill with conductance detection for low level ammonia monitoring in chloraminated water. Talanta. 2019; 200 ():256-262.
Chicago/Turabian StyleJianyin Huang; Christopher W.K. Chow; Philipp Kuntke; Lise Cruveiller; Gregory Gnos; David E. Davey; Peter Teasdale. 2019. "The development and evaluation of a microstill with conductance detection for low level ammonia monitoring in chloraminated water." Talanta 200, no. : 256-262.
A case study of applying chemometrics approach to develop a real-time industrial process early warning system using online measurements was conducted. An online spectrophotometer was installed for an eighteen-month monitoring study between 2013 and 2015 at the inlet of a wastewater treatment plant. During this time a web-based prototype portal with data integration, visualization, prediction and anomaly detection functions for complex online data sets was developed in-house to assess the spectral data acquired by the spectrophotometer together with other databases (such as rainfall and temperature). Several chemometrics options were trailed to extract useful operational information from the acquired data. In this paper, the anomaly detection function which includes pattern learning and comparison algorithms and a powerful user interface was described in detail. By using the functions, process upsets were successfully detected from the spectral data at the inlet of the treatment plant. The detected events/upsets were then compared with the treatment plant logs and they were found aligned well, which proved that the anomaly detection technique was effective and has the potential to inform decision to assist plant operators. In addition, the proposed anomaly detection technique used a flexible algorithm which also works with any similar time series data to detect other process related issues to provide real-time warning to support treatment plant operations.
Christopher W.K. Chow; Jixue Liu; Jiuyong Li; Nick Swain; Katherine Reid; Christopher P. Saint. Development of smart data analytics tools to support wastewater treatment plant operation. Chemometrics and Intelligent Laboratory Systems 2018, 177, 140 -150.
AMA StyleChristopher W.K. Chow, Jixue Liu, Jiuyong Li, Nick Swain, Katherine Reid, Christopher P. Saint. Development of smart data analytics tools to support wastewater treatment plant operation. Chemometrics and Intelligent Laboratory Systems. 2018; 177 ():140-150.
Chicago/Turabian StyleChristopher W.K. Chow; Jixue Liu; Jiuyong Li; Nick Swain; Katherine Reid; Christopher P. Saint. 2018. "Development of smart data analytics tools to support wastewater treatment plant operation." Chemometrics and Intelligent Laboratory Systems 177, no. : 140-150.
Sina Moradi; Christopher W.K. Chow; David Cook; Mary Drikas; Patrick Hayde; Rose Amal. A NEW APPROACH FOR WATER QUALITY NETWORK MODELLING. Water e-Journal 2018, 3, 1 -7.
AMA StyleSina Moradi, Christopher W.K. Chow, David Cook, Mary Drikas, Patrick Hayde, Rose Amal. A NEW APPROACH FOR WATER QUALITY NETWORK MODELLING. Water e-Journal. 2018; 3 (2):1-7.
Chicago/Turabian StyleSina Moradi; Christopher W.K. Chow; David Cook; Mary Drikas; Patrick Hayde; Rose Amal. 2018. "A NEW APPROACH FOR WATER QUALITY NETWORK MODELLING." Water e-Journal 3, no. 2: 1-7.
This paper reports the effects of pre-oxidation processes including ozone and ultraviolet (UV) irradiation prior to chloramination on microbiologically assisted monochloramine decay. Water samples with varying water qualities were pre-oxidated by ozone and UV irradiation, followed by determination of chemical and microbiological monochloramine decay (Fm). Both ozone and UV could effectively improve the reduction of microbial-like compounds responsible for monochloramine decay in treated water samples. Reductions in Fm values were observed for ozone contact times (Ct) greater than 5 mg min/L and UV doses greater than 30 mJ/cm2. However, UV was less effective than ozone in reducing Fm values in raw water samples. Complete removal of the microbiological component of the decay for raw water samples was not found either with ozone (even with Ct of 50 mg min/L) or UV (even with UV dose of 120 mJ/cm2). The effects of pre-oxidation processes on chemical (kc) and microbial (km) decay coefficients were assessed. Increasing both ozone Ct and UV dose ahead of chloramine did not affect the chemical decay component, but they changed the microbiological component of decay. Changes in organic matter after ozonation were also characterized using three-dimensional fluorescence excitation–emission matrix (3D-FEEM) spectroscopy, and correlations between 3D-FEEM spectroscopy results and Fm values were found. Intensities of humic-like, fulvic-like, microbial protein-like and aromatic protein-like substances were reduced by pre-ozonation. Based on the 3D-FEEM results, we can confirm that the slowdown of monochloramine decay rate is due to the reduction of marine humic-like substances and soluble microbial protein-like compounds by pre-ozonation.
Sina Moradi; Sam Hancock; Christopher W.K. Chow; John Van Leeuwen; Mary Drikas; Martin Harris; David Cook; Rose Amal. Assessment of ozone and UV pre-oxidation processes for mitigating microbiologically accelerated monochloramine decay. Journal of Environmental Chemical Engineering 2017, 6, 44 -51.
AMA StyleSina Moradi, Sam Hancock, Christopher W.K. Chow, John Van Leeuwen, Mary Drikas, Martin Harris, David Cook, Rose Amal. Assessment of ozone and UV pre-oxidation processes for mitigating microbiologically accelerated monochloramine decay. Journal of Environmental Chemical Engineering. 2017; 6 (1):44-51.
Chicago/Turabian StyleSina Moradi; Sam Hancock; Christopher W.K. Chow; John Van Leeuwen; Mary Drikas; Martin Harris; David Cook; Rose Amal. 2017. "Assessment of ozone and UV pre-oxidation processes for mitigating microbiologically accelerated monochloramine decay." Journal of Environmental Chemical Engineering 6, no. 1: 44-51.
Not availableXavier Cetó, Christopher Saint, Christopher W.K. Chow, Nicolas H. Voelcker, Beatriz Prieto-Simó
Xavier Cetó; Christopher Saint; Christopher W.K. Chow; Nicolas H. Voelcker; Beatriz Prieto-Simón. Electrochemical fingerprints of brominated trihaloacetic acids (HAA3) mixtures in water. Sensors and Actuators B: Chemical 2017, 247, 70 -77.
AMA StyleXavier Cetó, Christopher Saint, Christopher W.K. Chow, Nicolas H. Voelcker, Beatriz Prieto-Simón. Electrochemical fingerprints of brominated trihaloacetic acids (HAA3) mixtures in water. Sensors and Actuators B: Chemical. 2017; 247 ():70-77.
Chicago/Turabian StyleXavier Cetó; Christopher Saint; Christopher W.K. Chow; Nicolas H. Voelcker; Beatriz Prieto-Simón. 2017. "Electrochemical fingerprints of brominated trihaloacetic acids (HAA3) mixtures in water." Sensors and Actuators B: Chemical 247, no. : 70-77.
Minimizing particles in water is a key goal for improving drinking water quality and safety. The media filtration process, as the last step of the solid-liquid separation process, is largely influenced by the characteristics of flocs, which are formed and controlled within the coagulation process. In a laboratory-based study, the impacts of the physical characteristics of flocs formed using aluminum sulfate on the filtration treatment of two comparative water samples were investigated using a photometric dispersion analyzer and a filterability apparatus. In general, the optimum dosage for maximizing filterability was higher than that for minimizing turbidity under neutral pH conditions. For a monomeric aluminum-based coagulant, the charge neutralization mechanism produced better floc characteristics, including floc growth speed and size, than the sweep flocculation mechanism. In addition, the charge neutralization mechanism showed better performance compared to sweep flocculation in terms of DOC removal and floc filterability improvement for both waters, and showed superiority in turbidity removal only when the raw water had high turbidity. For the different mechanisms, the ways that floc characteristics impacted on floc filterability also differed. The low variation in floc size distribution obtained under the charge neutralization mechanism resulted in the flocs being amenable to removal by filtration processes. For the sweep flocculation mechanism, increasing the floc size improved the settling ability of flocs, resulting in higher filter efficiency.
Ruyuan Jiao; Rolando Fabris; Christopher Chow; Mary Drikas; John van Leeuwen; Dongsheng Wang; Zhizhen Xu. Influence of coagulation mechanisms and floc formation on filterability. Journal of Environmental Sciences 2017, 57, 338 -345.
AMA StyleRuyuan Jiao, Rolando Fabris, Christopher Chow, Mary Drikas, John van Leeuwen, Dongsheng Wang, Zhizhen Xu. Influence of coagulation mechanisms and floc formation on filterability. Journal of Environmental Sciences. 2017; 57 ():338-345.
Chicago/Turabian StyleRuyuan Jiao; Rolando Fabris; Christopher Chow; Mary Drikas; John van Leeuwen; Dongsheng Wang; Zhizhen Xu. 2017. "Influence of coagulation mechanisms and floc formation on filterability." Journal of Environmental Sciences 57, no. : 338-345.
A model was developed for estimation of N‐nitrosodimethylamine (NDMA) concentration in a case study of a chloraminated water distribution system in Australia using influencing parameters that had an impact on NDMA formation via a hybrid genetic algorithm method. The model was based on hydraulic retention time, temperature, and monochloramine residual. The genetic algorithm and quasi‐Newton optimization with a Broyden–Fletcher–Goldfarb–Shanno Hessian updating method were combined into a hybrid parameter optimization scheme for robust calibration of NDMA model parameters. In order to test the applicability and the accuracy of the proposed model, NDMA concentration and water quality characteristics for 220 post‐disinfection water samples collected between 2006 and 2016 were used. Good agreement between measured and estimated NDMA concentrations was observed by performing statistical analysis on an independent set of water sample data (R2 = 0.93). This modeling approach has the potential to be used as a decision support tool in order to manage and improve the chloramine disinfection process.
Sina Moradi; Christopher W.K. Chow; David Cook; Gayle Newcombe; Rose Amal. Estimating NDMA Formation in a Distribution System Using a Hybrid Genetic Algorithm. Journal AWWA 2017, 109, E265 -E272.
AMA StyleSina Moradi, Christopher W.K. Chow, David Cook, Gayle Newcombe, Rose Amal. Estimating NDMA Formation in a Distribution System Using a Hybrid Genetic Algorithm. Journal AWWA. 2017; 109 (6):E265-E272.
Chicago/Turabian StyleSina Moradi; Christopher W.K. Chow; David Cook; Gayle Newcombe; Rose Amal. 2017. "Estimating NDMA Formation in a Distribution System Using a Hybrid Genetic Algorithm." Journal AWWA 109, no. 6: E265-E272.
A model is developed to enable estimation of chloramine demand in full scale drinking water supplies based on chemical and microbiological factors that affect chloramine decay rate via nonlinear regression analysis method. The model is based on organic character (specific ultraviolet absorbance (SUVA)) of the water samples and a laboratory measure of the microbiological (Fm) decay of chloramine. The applicability of the model for estimation of chloramine residual (and hence chloramine demand) was tested on several waters from different water treatment plants in Australia through statistical test analysis between the experimental and predicted data. Results showed that the model was able to simulate and estimate chloramine demand at various times in real drinking water systems. To elucidate the loss of chloramine over the wide variation of water quality used in this study, the model incorporates both the fast and slow chloramine decay pathways. The significance of estimated fast and slow decay rate constants as the kinetic parameters of the model for three water sources in Australia was discussed. It was found that with the same water source, the kinetic parameters remain the same. This modelling approach has the potential to be used by water treatment operators as a decision support tool in order to manage chloramine disinfection.
Sina Moradi; Sanly Liu; Christopher Chow; John van Leeuwen; David Cook; Mary Drikas; Rose Amal. Chloramine demand estimation using surrogate chemical and microbiological parameters. Journal of Environmental Sciences 2017, 57, 1 -7.
AMA StyleSina Moradi, Sanly Liu, Christopher Chow, John van Leeuwen, David Cook, Mary Drikas, Rose Amal. Chloramine demand estimation using surrogate chemical and microbiological parameters. Journal of Environmental Sciences. 2017; 57 ():1-7.
Chicago/Turabian StyleSina Moradi; Sanly Liu; Christopher Chow; John van Leeuwen; David Cook; Mary Drikas; Rose Amal. 2017. "Chloramine demand estimation using surrogate chemical and microbiological parameters." Journal of Environmental Sciences 57, no. : 1-7.
Dissolved organic matter (DOM) in surface waters used for drinking purposes can vary markedly in character depending on its source within catchments and the timing and intensity of rainfall events. Here we report the findings of a study on the character and concentration of DOM in waters collected during different seasons from Myponga River and Reservoir, South Australia. The character of DOM was assessed in terms of its treatability by enhanced coagulation and potential for disinfection by-product i.e. trihalomethane (THM) formation. During the wet seasons (winter and spring), water samples from the river had higher DOC concentrations (X¯: 21 mg/L) and DOM of higher average molecular weight (AMW: 1526 Da) than waters collected during the dry seasons (summer and autumn: DOC: 13 mg/L; AMW: 1385 Da). Even though these features led to an increase in the percentage removal of organics by coagulation with alum (64% for wet compared with 53% for dry season samples) and a lower alum dose rate (10 versus 15 mg alum/mg DOC removal), there was a higher THM formation potential (THMFP) from wet season waters (treated waters: 217 μg/L vs 172 μg/L). For reservoir waters, samples collected during the wet seasons had an average DOC concentration (X¯: 15 mg/L), percentage removal of organics by alum (54%), alum dose rates (13 mg/mg DOC) and THMFP (treated waters: 207 μg/L) that were similar to samples collected during the dry seasons (mean DOC: 15 mg/L; removal of organics: 52%; alum dose rate: 13 mg/mg DOC; THMFP: 212 μg/L for treated waters). These results show that DOM present in river waters and treatability by alum are highly impacted by seasonal environmental variations. However these in reservoir waters exhibit less seasonal variability. Storage of large volumes of water in the reservoir enables mixing of influent waters and stabilization of water quality.
John Awad; John van Leeuwen; Christopher W.K. Chow; Ronald J. Smernik; Sharolyn J. Anderson; Jim W. Cox. Seasonal variation in the nature of DOM in a river and drinking water reservoir of a closed catchment. Environmental Pollution 2017, 220, 788 -796.
AMA StyleJohn Awad, John van Leeuwen, Christopher W.K. Chow, Ronald J. Smernik, Sharolyn J. Anderson, Jim W. Cox. Seasonal variation in the nature of DOM in a river and drinking water reservoir of a closed catchment. Environmental Pollution. 2017; 220 ():788-796.
Chicago/Turabian StyleJohn Awad; John van Leeuwen; Christopher W.K. Chow; Ronald J. Smernik; Sharolyn J. Anderson; Jim W. Cox. 2017. "Seasonal variation in the nature of DOM in a river and drinking water reservoir of a closed catchment." Environmental Pollution 220, no. : 788-796.
Not availableXavier Cetó, Christopher P. Saint, Christopher W.K. Chow, Nicolas H. Voelcker, Beatriz Prieto-Simó
Xavier Cetó; Christopher P. Saint; Christopher W.K. Chow; Nicolas H. Voelcker; Beatriz Prieto-Simón. Electrochemical detection of N‐nitrosodimethylamine using a molecular imprinted polymer. Sensors and Actuators B: Chemical 2016, 237, 613 -620.
AMA StyleXavier Cetó, Christopher P. Saint, Christopher W.K. Chow, Nicolas H. Voelcker, Beatriz Prieto-Simón. Electrochemical detection of N‐nitrosodimethylamine using a molecular imprinted polymer. Sensors and Actuators B: Chemical. 2016; 237 ():613-620.
Chicago/Turabian StyleXavier Cetó; Christopher P. Saint; Christopher W.K. Chow; Nicolas H. Voelcker; Beatriz Prieto-Simón. 2016. "Electrochemical detection of N‐nitrosodimethylamine using a molecular imprinted polymer." Sensors and Actuators B: Chemical 237, no. : 613-620.