scholarly journals Robust Placement of Water Quality Sensor for Long-Distance Water Transfer Projects Based on Multi-Objective Optimization and Uncertainty Analysis

2021 ◽  
Vol 13 (4) ◽  
pp. 1834
Author(s):  
Yu Li ◽  
Jinggang Chu ◽  
Guozhen Wei ◽  
Sifan Jin ◽  
Tiantian Yang ◽  
...  
Keyword(s):  
Water Quality ◽  
Detection Rate ◽  
Sensor Placement ◽  
Water Transfer ◽  
Water Diversion ◽  
Optimal Placement ◽  
Detection Accuracy ◽  
Detection Time ◽  
Long Distance ◽  
Water Quality Sensors

It is important to place water quality sensors along open channels in long-distance water transfer projects optimally for rapid source identification and efficient management of sudden water contamination. A new framework which considers multiple objectives, including earliest detection time, lowest missing detection rate and lowest sensor cost, and combines the randomness of injected contaminant type and contaminant incident consisting of contaminant intrusion location, time and mass, was established to obtain optimal placement of water quality sensor with better robustness in this paper. The middle route of the South-to-North Water Diversion Project in China was chosen as a case study, and it was found that both missing detection rate and detection time decrease with sensor cost gradually; furthermore, given the higher detecting precision, the detection accuracy and efficiency would be improved, a smaller number of water quality sensors would be needed, and the ten key placement positions where sensor with different detecting precision placed could be identified. Under the constraints of the allowable maximum missing detection rate, 1.00%, and detection time, 120.00 min, the detecting precision of 0.20 mg/L and 38 sensors placed could be selected as the optimal sensor placement scheme. Finally, with the consideration of contaminant uncertainty, the sensor placement scheme with better robustness could be constructed. The proposed framework would be helpful in solving the problem of water quality sensor placement with high practicality and efficiency in long-distance water transfer projects.

scholarly journals On the Distributional Characterization of Graph Models of Water Distribution Networks in Wasserstein Spaces

2021 ◽  
Author(s):  
Antonio Candelieri ◽  
Andrea Ponti ◽  
Francesco Archetti
Keyword(s):  
Water Quality ◽  
Probability Distribution ◽  
Water Distribution ◽  
Probability Distributions ◽  
Sensor Placement ◽  
Distribution Networks ◽  
Detection Time ◽  
Optimal Sensor Placement ◽  
Discrete Probability ◽  
Water Quality Sensors

This paper is focused on two topics very relevant in water distribution networks (WDNs): vulnerability assessment and the optimal placement of water quality sensors. The main novelty element of this paper is to represent the data of the problem, in this case all objects in a graph underlying a water distribution network, as discrete probability distributions. For vulnerability (and the related issue of re-silience) the metrics from network theory, widely studied and largely adopted in the water research community, reflect connectivity expressed as closeness centrality or, betweenness centrality based on the average values of shortest paths between all pairs of nodes. Also network efficiency and the related vulnerability measures are related to average of inverse distances. In this paper we propose a different approach based on the discrete probability distribution, for each node, of the node-to-node distances. For the optimal sensor placement, the elements to be represented as dis-crete probability distributions are sub-graphs given by the locations of water quality sensors. The objective functions, detection time and its variance as a proxy of risk, are accordingly represented as a discrete e probability distribution over contamination events. This problem is usually dealt with by EA algorithm. We’ll show that a probabilistic distance, specifically the Wasserstein (WST) distance, can naturally allow an effective formulation of genetic operators. Usually, each node is associated to a scalar real number, in the optimal sensor placement considered in the literature, average detection time, but in many applications, node labels are more naturally expressed as histograms or probability distributions: the water demand at each node is naturally seen as a histogram over the 24 hours cycle. The main aim of this paper is twofold: first to show how different problems in WDNs can take advantage of the representational flexibility inherent in WST spaces. Second how this flexibility translates into computational procedures.

scholarly journals A Gateway to Rapid Prediction of Water Quality: A Case Study in China’s South-to-North Water Diversion Project

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2407
Author(s):  
Yuxuan Zhang ◽  
Ranhang Zhao ◽  
Haofang Wang ◽  
Tao Peng ◽  
Huaqing Zhao
Keyword(s):  
Water Pollution ◽  
Water Quality ◽  
Water Transfer ◽  
Water Diversion ◽  
Successful Operation ◽  
Long Distance ◽  
Rapid Prediction ◽  
Water Diversion Project ◽  
North Water ◽  
Sudden Water Pollution

Water quality assurance is the primary factor for the successful operation of water diversion projects across river basins. The rapid prediction of water pollution is the basis for timely and effective emergency control and disposal measures. In China, since the open channels intersect with numerous waterways and traffic arteries, water transfer projects are prone to sudden water pollution accidents. In this paper, the rapid prediction method was developed for sudden water pollution accidents that possibly occurred in the East Route of the South-to-North Water Diversion Project (ERP) in Shandong Province. With the empirical formula of the pollution transfer law, a rapid prediction model of water quality (WQRP) was established based on the simulation of the typical accidents in the main channel. Finally, four typical accidents were selected as application examples, and the prediction results were compared with the results from a computer numerical simulation to demonstrate the validity of the model. The results showed that the prediction results by the WQRP model meet the accuracy requirements. This method is of great significance for providing water transport security in the extreme conditions of long-distance water transfer projects.

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.

scholarly journals A real-time, rapid emergency control model for sudden water pollution accidents in long-distance water transfer projects

2016 ◽  
Vol 17 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Guobin Xu ◽  
Yan Long ◽  
Chao Ma
Keyword(s):  
Water Pollution ◽  
Real Time ◽  
Peak Concentration ◽  
Water Transfer ◽  
Water Diversion ◽  
Long Distance ◽  
Emergency Control ◽  
Rapid Prediction ◽  
North Water ◽  
Sudden Water Pollution

A real-time, rapid emergency control (EC) model is proposed to cope with sudden water pollution accidents in long-distance water transfer projects. The EC model outputs the method of EC based on pollutant properties. A generalized form of EC model is proposed and tested with a demonstrative project. The rapid prediction formulas of emergency control parameters (ECPs) are proposed under different states of water diversion. The closing times of check gates and the pollution range are calculated by the rapid prediction formulas of ECPs. A case study is examined under the scenario of a sucrose spill in a demonstrative project conducted in the Fangshui to Puyang channel of the Beijing–Shijiazhuang Emergency Water Supply Project in the middle route of the South-to-North Water Transfer Project. The relative errors of peak concentration and arrival time of peak concentration are less than 20%. However, we could not use an actual toxic soluble pollutant to validate the EC model, so we performed the experiment with sucrose to test the EC model based on its concentration variation. The final result shows that the model is able to play a fundamental role in the decisions involved in the Emergency Environmental Decision Support System.

scholarly journals Succession of phytoplankton in a shallow lake under the alternating influence of runoff and reverse water transfer

2020 ◽  
Vol 51 (5) ◽  
pp. 1077-1090
Author(s):  
Qing Li ◽  
Guoqiang Wang ◽  
Zhongxin Tan ◽  
Hongqi Wang
Keyword(s):  
Water Quality ◽  
Phytoplankton Community ◽  
Diversity Index ◽  
Oxygen Demand ◽  
Aquatic Organisms ◽  
Water Transfer ◽  
Water Diversion ◽  
Clear Understanding ◽  
Total Density ◽  
The Impact

Abstract Both runoff and water diversion can interfere with the physical and chemical environment of a lake and affect aquatic organisms. In this study, previously obtained data were used to analyze the phytoplankton community, water quality, water level, and temperature in Dongping Lake (DPH) before, during, and after the water diversion caused by the South-to-North Water Transfer Project. The results showed that the total density and diversity index of phytoplankton decreased in the water transfer period, and was related to low temperature. Temperature also affected the recovery of phytoplankton community structure when the water transfer period ended. In a water transfer cycle, changes in dominant genera were more drastic than that of a whole phytoplankton community, and dominant genera were sensitive to total phosphorus (TP) and total nitrogen (TN) changes. Water transfer alleviated the deterioration of water quality in DPH, but water transfer process increased the risk of water pollution. Runoff from Dawen River carried TN, TP, and chemical oxygen demand (COD) into DPH in the rainy season, which indirectly affected phytoplankton, while it also carried phytoplankton directly into DPH. Overall, these findings provide a clear understanding of the impact of water transfer projects on ecology in shallow lakes.

scholarly journals Untangling Microbiota Diversity and Assembly Patterns in the World's Largest Water Diversion Canal

2021 ◽  
Author(s):  
Lu Zhang ◽  
Wei Yin ◽  
Chao Wang ◽  
Aijing Zhang ◽  
Hong Zhang ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Environment ◽  
Null Model ◽  
Water Quality Monitoring ◽  
Water Diversion ◽  
Ecological Knowledge ◽  
Canal Water ◽  
Long Distance ◽  
Environmental Selection ◽  
Microbial Proliferation

Large water diversion projects are important constructions for reallocation of human-essential water resources. Deciphering microbiota dynamics and assembly mechanisms underlying canal water ecosystem services especially during long-distance diversion is the prerequisite for water quality monitoring, biohazard warning and sustainable management. Using a 1432-km canal of the South-to-North Water Diversion Projects as a model system, we answer three central questions: how bacterial and micro-eukaryotic communities spatio-temporally develop, how much ecological stochasticity contributes to microbiota assembly, and which immigrating populations better survive and navigate across the canal. We applied quantitative ribosomal RNA gene sequence analyses to investigate canal water microbial communities sampled over a year, as well as null model- and neutral model-based approaches to disentangle the microbiota assembly processes. Our results showed clear microbiota dynamics in community composition driven by seasonality more than geographic location, and seasonally dependent influence of environmental parameters. Overall, bacterial community was largely shaped by deterministic processes, whereas stochasticity dominated micro-eukaryotic community assembly. We defined a local growth factor (LGF) and demonstrated its innovative use to quantitatively infer microbial proliferation, unraveling taxonomically dependent population response to local environmental selection across canal sections. Using LGF as a quantitative indicator of immigrating capacities, we also found that most micro-eukaryotic populations (82%) from the source lake water sustained growth in the canal and better acclimated to the hydrodynamical water environment than bacteria (67%). Taxa inferred to largely propagate include Limnohabitans sp. and Cryptophyceae, potentially contributing to water auto-purification. Combined, our work poses first and unique insights into the microbiota assembly patterns and dynamics in the world's largest water diversion canal, providing important ecological knowledge for long-term sustainable water quality maintenance in such a giant engineered system.

scholarly journals Effects of culvert length and flow rates of raw water transport on biofilm development and water quality

2021 ◽  
Author(s):  
Ruikang Xue ◽  
Tinglin Huang ◽  
Gang Wen ◽  
Junle Yan ◽  
Qian Liu
Keyword(s):  
Water Quality ◽  
Water Transport ◽  
Cell Number ◽  
Water Transfer ◽  
Plate Count ◽  
Raw Water ◽  
Long Distance ◽  
Biofilm Growth ◽  
Flow Rates ◽  
Biofilm Development

Abstract Long-distance water transfer projects are important for water allocation. To enhance our understanding of biofilm growth and changes in water quality during raw water transfer, raw water through long-distance non-full culvert at flow rates of 1.4−2.0 m/s was studied.The results revealed that: (1) the biofilm total cell number (TCC) and heterotrophic plate count (HPC) were the highest at a flow rate of 1.5 m/s, which were 3.7E + 04 cells /cm2 and 1.1E + 03 CFU/cm2, respectively; (2) proteobacteria had the highest relative abundance (RA) among all samples, and the RA in biofilm (78.85%) was higher than that in water (48%−59%); (3) when the pollutants and biofilm were partially shed, the total phosphorus (TP), permanganate index (CODMn), and dissolved organic carbon (DOC) increased by 0.011, 0.36, and 0.5 mg/L at most, respectively; and (4) dissolved oxygen (DO) was sufficient during non-full flow water transport and nitrification occurred. The highest removal rates of ammonium nitrogen (NH+4-N) and nitrous nitrogen (NO2--N) reached 27.16% and 66.76%, respectively. At the flow rates of 2.0 m/s, the efficiency decreased to 10.47% and 41.25%, respectively, due to the shedding of biofilm.

scholarly journals Study on Long-term Water Quality Protection Mechanism Framework of Inter-basin Water Diversion Protect

2018 ◽  
Vol 246 ◽  
pp. 01071
Author(s):  
YIN Xiaolin
Keyword(s):  
Water Quality ◽  
Supply And Demand ◽  
Feedback Mechanism ◽  
Water Transfer ◽  
Water Diversion ◽  
Domestic Water ◽  
Protection Mechanism ◽  
Water Quality Protection ◽  
Basin Water

With the increasing and complicated contradiction between the supply and demand of water resources in recent years, a number of inter-basin water diversion projects have been built in various places in China. The water supply objects of the inter-basin water diversion projects are mostly industrial and domestic water, and the water quality is closely related to the success or failure of the water transfer project, which makes it necessary to establish a long-term water quality protection mechanism. On the basis of analyzing major issues in water quality protection in inter-basin water transfer projects, a long-term mechanism framework for water quality protection was established and elaborated from the aspects of institutional system, water quality goals, risk management, guarantee conditions, feedback mechanism, technical evaluation, administrative assessment, public participation, incentive measures, aiming to provides reference for the water quality safety inter-basin water diversion projects.

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