scholarly journals Development and identification of a multi-species water quality model for reclaimed water distribution systems

2015 ◽  
Vol 5 (3) ◽  
pp. 360-371
Author(s):  
Shun Li ◽  
Fu Sun ◽  
Siyu Zeng ◽  
Xin Dong ◽  
Pengfei Du
Keyword(s):  
Water Quality ◽  
Distribution Systems ◽  
Water Distribution ◽  
Reclaimed Water ◽  
Water Distribution Systems ◽  
Water Quality Model ◽  
Bulk Liquid ◽  
Model Parameters ◽  
Quality Model ◽  
Long Distance

With the rapid development of a centralized wastewater reuse scheme in China, water quality concerns arise considering the long-distance transport of reclaimed water in distribution systems from wastewater treatment plants to points of use. To this end, a multi-species water quality model for reclaimed water distribution systems (RWDSs) was developed and validated against the data from part of a full-scale RWDS in Beijing. The model could simulate organics, ammonia nitrogen, residual chlorine, inert particles, and six microbial species, i.e. fecal coliforms, Enterococcus spp., Salmonella spp., Mycobacterium spp., and other heterotrophic and autotrophic bacteria, in both the bulk liquid and the biofilm. Altogether, 56 reaction processes were involved, and 37 model parameters and seven initial values were identified. Despite the limited monitoring data and the associated gross uncertainty, the model could simulate the reclaimed water quality in the RWDS with acceptable accuracy. Regional sensitivity analysis suggested that the model had a balanced structure with a large proportion of sensitive parameters, and the sensitivity of model parameters could be reasonably interpreted by current knowledge or observation. Furthermore, the most sensitive model parameters could generally be well identified with uncertainties significantly reduced, which also favored the trustworthiness of the model. Finally, future plans to improve and apply the model were also discussed.

Water quality model parameter identification of an open channel in a long distance water transfer project based on finite difference, difference evolution and Monte Carlo

2013 ◽  
Vol 69 (3) ◽  
pp. 587-594 ◽  
Author(s):  
Dongguo Shao ◽  
Haidong Yang ◽  
Yi Xiao ◽  
Biyu Liu
Keyword(s):  
Water Quality ◽  
Open Channel ◽  
Differential Evolution Algorithm ◽  
Water Transfer ◽  
Water Quality Model ◽  
Model Parameters ◽  
Quality Model ◽  
Long Distance ◽  
Mcmc Simulation ◽  
Evolution Algorithm

A new method is proposed based on the finite difference method (FDM), differential evolution algorithm and Markov Chain Monte Carlo (MCMC) simulation to identify water quality model parameters of an open channel in a long distance water transfer project. Firstly, this parameter identification problem is considered as a Bayesian estimation problem and the forward numerical model is solved by FDM, and the posterior probability density function of the parameters is deduced. Then these parameters are estimated using a sampling method with differential evolution algorithm and MCMC simulation. Finally this proposed method is compared with FDM–MCMC by a twin experiment. The results show that the proposed method can be used to identify water quality model parameters of an open channel in a long distance water transfer project under different scenarios better with fewer iterations, higher reliability and anti-noise capability compared with FDM–MCMC. Therefore, it provides a new idea and method to solve the traceability problem in sudden water pollution accidents.

Determination of cast iron pipe wall decay coefficient for combined chlorine in a municipal water distribution system

2015 ◽  
Vol 42 (4) ◽  
pp. 250-258 ◽  
Author(s):  
Megan J. Liu ◽  
Stephen Craik ◽  
David Z. Zhu
Keyword(s):  
Water Quality ◽  
Cast Iron ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution System ◽  
Water Quality Model ◽  
Quality Model ◽  
Decay Coefficient ◽  
Municipal Water

Predicting disinfectant concentrations in water distribution systems using water quality models requires the input of the wall decay coefficient of the disinfectant. In this study, field water sampling data was integrated with network hydraulic and water quality model simulations of a section of the municipal water distribution system in the City of Edmonton, composed of predominantly cast iron piping, to determine a wall decay coefficient for combined chlorine (chloramine). Unique combined chlorine wall decay coefficients that provided the best fit of model-predicted chlorine concentrations to the field data were determined at two temperatures. Using the determined wall decay coefficients, the water quality model can be used to predict combined chlorine concentrations.

Implications of organic carbon in the deterioration of water quality in reclaimed water distribution systems

2010 ◽  
Vol 44 (18) ◽  
pp. 5367-5375 ◽  
Author(s):  
Lauren A. Weinrich ◽  
Patrick K. Jjemba ◽  
Eugenio Giraldo ◽  
Mark W. LeChevallier
Keyword(s):  
Water Quality ◽  
Organic Carbon ◽  
Distribution Systems ◽  
Water Distribution ◽  
Reclaimed Water ◽  
Water Distribution Systems

Effects of BAC-filtration, disinfection, and temperature on water quality in simulated reclaimed water distribution systems

2020 ◽  
Vol 6 (11) ◽  
pp. 3106-3120
Author(s):  
Ni Zhu ◽  
Sudeshna Ghosh ◽  
Laurel Strom ◽  
Amy Pruden ◽  
Marc A. Edwards
Keyword(s):  
Water Quality ◽  
Distribution Systems ◽  
Water Distribution ◽  
Potable Water ◽  
Reclaimed Water ◽  
Water Distribution Systems

The distinct characteristics of reclaimed versus potable water have important implications for design and operation of reclaimed water distribution systems (RWDSs).

scholarly journals Influence of residence time of reclaimed water within distribution systems on water quality

2013 ◽  
Vol 3 (3) ◽  
pp. 185-196 ◽  
Author(s):  
Oluyomi M. Ajibode ◽  
Channah Rock ◽  
Kelly Bright ◽  
Jean E. T. McLain ◽  
Charles P. Gerba ◽  
...  
Keyword(s):  
Water Quality ◽  
Residence Time ◽  
Distribution Systems ◽  
Water Distribution ◽  
Reclaimed Water ◽  
Water Distribution Systems ◽  
Geographic Location ◽  
Wastewater Reclamation ◽  
Microbial Water Quality ◽  
Water Based

The influence of residence time of reclaimed water within water distribution systems on microbial water quality was evaluated in two wastewater reclamation facilities in southern Arizona over a 15-month period. These utilities differed in age, geographic location, means of treatment, and disinfection (i.e. UV versus chlorine). At both facilities, samples were collected from the point of compliance (POC) directly after disinfection, and at discrete locations with increasing distance from the POC. Following entry into reclaimed water distribution systems, overall microbial water quality decreased rapidly due to microbial regrowth. However, following such regrowth, microbial concentrations remained relatively constant. Water-based opportunistic pathogens (Legionella, Mycobacterium, and Aeromonas) were frequently detected in both reclaimed water systems. In contrast, waterborne indicators such as Escherichia coli and Enterococcus were rarely detected, and only at low concentrations. These dates suggest the need for new indicators of water-based pathogens to be developed. Rechlorination in one of the distribution systems only reduced the concentration of bacteria temporarily due to rapid dissipation of chlorine, and subsequent regrowth of both water-based pathogens and indicators. Amoebic activity was detected in approximately one-third of all samples tested from both utilities, but was not correlated with either water-based pathogens or indicators.

scholarly journals Modeling Bacterial Regrowth and Trihalomethane Formation in Water Distribution Systems

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 463
Author(s):  
Gopinathan R. Abhijith ◽  
Leonid Kadinski ◽  
Avi Ostfeld
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Mechanistic Model ◽  
Water Distribution Systems ◽  
Sensitivity Study ◽  
Operating Conditions ◽  
Growth Rate Constant ◽  
Model Parameters ◽  
Bacterial Regrowth ◽  
The Impact

The formation of bacterial regrowth and disinfection by-products is ubiquitous in chlorinated water distribution systems (WDSs) operated with organic loads. A generic, easy-to-use mechanistic model describing the fundamental processes governing the interrelationship between chlorine, total organic carbon (TOC), and bacteria to analyze the spatiotemporal water quality variations in WDSs was developed using EPANET-MSX. The representation of multispecies reactions was simplified to minimize the interdependent model parameters. The physicochemical/biological processes that cannot be experimentally determined were neglected. The effects of source water characteristics and water residence time on controlling bacterial regrowth and Trihalomethane (THM) formation in two well-tested systems under chlorinated and non-chlorinated conditions were analyzed by applying the model. The results established that a 100% increase in the free chlorine concentration and a 50% reduction in the TOC at the source effectuated a 5.87 log scale decrement in the bacteriological activity at the expense of a 60% increase in THM formation. The sensitivity study showed the impact of the operating conditions and the network characteristics in determining parameter sensitivities to model outputs. The maximum specific growth rate constant for bulk phase bacteria was found to be the most sensitive parameter to the predicted bacterial regrowth.

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