Autocalibration of a water distribution model for water quality parameters using GA

2006 ◽  
Vol 98 (9) ◽  
pp. 109-123 ◽  
Author(s):  
G.R. Munavalli ◽  
M.S. Mohan Kumar
Water SA ◽  
2019 ◽  
Vol 45 (2 April) ◽  
Author(s):  
Denis Nono ◽  
Phillimon T Odirile ◽  
Innocent Basupi ◽  
Bhagabat P Parida

Assessment of probable causes of chlorine decay in water distribution systems of Gaborone city, Botswana Gaborone city water distribution system (GCWDS) is rapidly expanding and has been faced with the major problems of high water losses due to leakage, water shortages due to drought and inadequate chlorine residuals at remote areas of the network. This study investigated the probable causes of chlorine decay, due to pipe wall conditions and distribution system water quality in the GCWDS. An experimental approach, which applied a pipe-loop network model to estimate biofilm growth and chlorine reaction rate constants, was used to analyse pipe wall chlorine decay. Also, effects of key water quality parameters on chlorine decay were analysed. The water quality parameters considered were: natural organic matter (measured by total organic carbon, TOC; dissolved organic carbon, DOC; and ultraviolet absorbance at wavelength 254, UVA-254, as surrogates), inorganic compounds (iron and manganese) and heterotrophic plate count (HPC). Samples were collected from selected locations in the GCWDS for analysis of water quality parameters. The results of biofilm growth and chlorine reaction rate constants revealed that chlorine decay was higher in pipe walls than in the bulk of water in the GCWDS. The analysis of key water quality parameters revealed the presence of TOC, DOC and significant levels of organics (measured by UVA-254), which suggests that organic compounds contributed to chlorine decay in the GCWDS. However, low amounts of iron and manganese (< 0.3 mg/L) indicated that inorganic compounds may have had insignificant contributions to chlorine decay. The knowledge gained on chlorine decay would be useful for improving water treatment and network operating conditions so that appropriate chlorine residuals are maintained to protect the network from the risks of poor water quality that may occur due to the aforementioned problems.


2015 ◽  
Vol 61 (12) ◽  
pp. 965-976 ◽  
Author(s):  
Daniel B. Scott ◽  
Michele I. Van Dyke ◽  
William B. Anderson ◽  
Peter M. Huck

The potential for regrowth of nitrifying microorganisms was monitored in 2 full-scale chloraminated drinking water distribution systems in Ontario, Canada, over a 9-month period. Quantitative PCR was used to measure amoA genes from ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), and these values were compared with water quality parameters that can influence nitrifier survival and growth, including total chlorine, ammonia, temperature, pH, and organic carbon. Although there were no severe nitrification episodes, AOB and AOA were frequently detected at low concentrations in samples collected from both distribution systems. A culture-based presence–absence test confirmed the presence of viable nitrifiers. AOB were usually present in similar or greater numbers than AOA in both systems. As well, AOB showed higher regrowth potential compared with AOA in both systems. Statistically significant correlations were measured between several water quality parameters of relevance to nitrification. Total chlorine was negatively correlated with both nitrifiers and heterotrophic plate count (HPC) bacteria, and ammonia levels were positively correlated with nitrifiers. Of particular importance was the strong correlation between HPC and AOB, which reinforced the usefulness of HPC as an operational parameter to measure general microbiological conditions in distribution systems.


Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1916
Author(s):  
Yuchuan Lai ◽  
David A. Dzombak

Drinking water distribution systems (DWDS) are affected by climate change and this work aimed to assess the effect of changing ambient air temperature on the water temperature and various water quality parameters in DWDS. A water temperature estimation model was identified and evaluated at seven specific locations in the U.S. and water quality parameters were assessed with a case study for Washington D.C. Preliminary estimation of changes in water temperature and two temperature-related parameters (the chlorine decay rate and bacterial activity) were developed for 91 U.S. cities using local air temperature observations and projections. Estimated water temperature changes in DWDS are generally equivalent to air temperature changes on an annual average basis, suggesting modest changes for the assessed historical periods and possibly more intensified changes in the future with greater increase in air temperature. As higher water age can amplify the temperature effect and the effects of temperature on some water quality parameters can be inter-related, yielding an aggregated effect, evaluation of extreme cases for DWDS will be of importance. In responding to changing climate conditions, assessments of DWDS water temperature changes and resulting impacts on water quality merit more attention to ensure appropriate adaptation of DWDS design and management.


Author(s):  
Keya Chowdhury ◽  
Aysha Akter

Abstract Rapid urbanization poses challenges to meet the increased water supply demands. Apart from the quantity, the distributed water quality often fails to meet the permissible level. This study aimed to conduct a citywide spatio-temporal variation of water quality parameters. Water sampling points were selected by applying the Analytical Hierarchical Process (AHP) technique using ArcGIS considering pipe leakage, source water quality, pipe age, and pipe materials. The Chattogram city comprises 397 km of pipes; pipe material distribution shows 71.28% PVC, 20.94% asbestos, 5.16% mild steel, 2.17% ductile, and 0.45% cast iron. The citywide pipe network was established in 1963; 20.87% of pipes aged over 30 years, 15.07% 20–30 years, 26.38% 10–20 years, and 37.68% pipelines are relatively new, i.e., within 0–10 years. Eight water quality parameters, i.e., pH, temperature, turbidity, biochemical oxygen demand after five days (BOD5), total coliform, fecal coliform, chloride, and residual chlorine, were collected from the secondary source cross-checked by field survey. Computation of the Water Quality Index (WQI) was interpolated using Inverse Distance Weighted (IDW) method to generate a WQI map. Thus, this study could be a basis to improve the treatment system and proper distribution network maintenance.


2019 ◽  
Vol 19 (6) ◽  
pp. 1785-1792 ◽  
Author(s):  
Silvia Tinelli ◽  
Ilan Juran

Abstract This research aims to simulate bio-contamination risk propagation under real-life conditions in the water distribution system (WDS) of Lille University's Scientific City Campus (France), solving the source identification and the response modeling. Neglecting dynamic reactions and not considering the possible chemical decay of most of the contaminants leads to an overestimation of the exposed population. Therefore, unlike the available event detection models, this study considers the interrelated change of several water-quality parameters such as free chlorine concentration, pH, alkalinity, and total organic carbon (TOC) resulting from the pollutants blending. In fact, starting from regular WDS monitoring, the baseline thresholds for each of the mentioned parameters are established; then, significant deviations from the baseline are used as indication for contaminations. For this reason, the purpose of the research was to develop and demonstrate the feasibility of an artificial intelligence (AI)-based smart monitoring system that will effectively enable water operators to ensure a quasi real-time quality control for early chemical and/or bio-contamination detection and preemptive risk management. Advanced pattern recognizers, such as Support Vector Machines (SVMs), and innovative sensing technology solutions, such as Artificial Neural Network (ANN), have been used for this purpose, identifying the anomalies and the severity-level assessment.


2018 ◽  
Vol 4 (10) ◽  
pp. 1564-1576 ◽  
Author(s):  
Gyan Chhipi-Shrestha ◽  
Manuel Rodriguez ◽  
Rehan Sadiq

A framework for estimating the concentration of unregulated disinfection by-products in water distribution using ΔCl2 and other basic water quality parameters.


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