Rapid assessment of drinking water quality: a handbook for implementation

Water is a basic human right as recently re-clarified in General Comment 15 of the Committee on Economic, Social and Cultural Rights. The importance of water for health and development has been reflected in international policy initiatives since the International Decade for Water Supply and Sanitation Development (the 1980s). This was further emphasised by the Millennium Declaration Goal to halve the proportion of the World's population that lacks access to water supply and most recently the identification of water and sanitation as a highest priority issue by the Commission for Sustainable Development. Since the 1960s, WHO has periodically reported on the development of the access to safe drinking-water sources; this is now implemented as a joint programme of work with UNICEF through the WHO/UNICEF Joint Monitoring Programme (JMP) for Water Supply and Sanitation. In recent reviews and evaluations the need for JMP to progressively address new and emerging priorities has been highlighted. As part of the ongoing plan of work of JMP, a major initiative to more comprehensively take account of water quality issues has been initiated. This handbook has been developed as a resource to support the systematic evaluation of drinking-water quality status at country and local levels. It is hoped that it will be useful to those interested in describing and understanding drinking-water quality status in the context of JMP at national/state levels and on a project basis

Rapid asssessment of drinking-water quality: a handbook for implementation

The JMP Rapid assessment of drinking-water quality (RADWQ) was conceived by WHO and UNICEF to explore the quality of drinking-water from "improved" sources. Results in five pilot countries showed a wide range of conditions, from full compliance with the WHO Drinking-water Quality Guidelines to specific sources in a given country only meeting standards in 34% of the samples. Further efforts along the lines of RADWQ will take global water quality testing out of the strict sphere of monitoring into the broader field of capacity development. The RADWQ handbook describes the methods and procedures applied by WHO and UNICEF in the five countries, for adoption by any authority or institution that wants to prepare a snapshot of the quality of "improved" sources of drinking-water, as a first step towards strengthening drinking-water quality regulations

Rapid Assessment of Drinking-water Quality: A Handbook for Implementation

Given that the use of an "improved" drinking-water source is a not a foolproof perfect guarantee of the water's safety, this handbook was developed to probe into the question, to what extent the quality of drinking-water from "improved" sources deviates from the assumption that it is safe. This handbook describes methods and procedures applied in the Rapid Assessment of Drinking-water Quality (RADWQs) carried out by WHO and UNICEF in five pilot countries -- they can be adopted by any authority or institution that wants to prepare a snapshot of the quality of "improved" sources of drinking-water, as a first step towards strengthening drinking-water quality regulatio

Model predictive control of water quality in drinking water distribution systems considering disinfection by-products

The shortage in water resources have been observed all over the world. However, the safety of drinking water has been given much attention by scientists because the disinfection will react with organic matters in drinking water to generate disinfection by-products (DBPs) which are considered as the cancerigenic matters. Although much research has been carried out on the water quality control problem in DWDS, the water quality model considered is linear with only chlorine dynamics. Compared to the linear water quality model, the nonlinear water quality model considers the interaction between chlorine and DBPs dynamics. The thesis proposes a nonlinear model predictive controller which utilises the newly derived nonlinear water quality model as a control alternative for controlling water quality. EPANET and EPANET-MSN are simulators utilised for modelling in the developed nonlinear MPC controller. Uncertainty is not considered in these simulators. This thesis proposes the bounded PPM in a form of multi-input multi-output to robustly bound parameters of chlorine and DBPs jointly and to robustly predict water quality control outputs for quality control purpose. The methodologies and algorithms developed in this thesis are verified by applying extended case studies to the example DWDS. The simulation results are presented and critically analysed

Segmenting Multivariate Time Series of Water Flow : a Prior Tool for Contamination Warning Systems

International audienceDrinking Water Distribution Networks (WDN) are critical infrastructures exposed to the risk of accidental and intentional contaminations. To ensure protection of drinking water, there is an important need to design automatic and secure Early Warning Systems (EWS). Online monitoring of water quality into a WDN is a challenging problem due to the complexity of hydraulic networks. Conventional detection methods deal with specific contaminants and usually assume a stationary state of the WDN meanwhile such problem is hardly addressed when operational conditions are changing. This paper introduces a generic methodology based on a temporal analysis in order to extract prior knowledge for warning detectors. Frequent types of operating period are extracted and for each period, upstream / downstream relationships into the WDN can be found. The procedure is fully data-driven and prevents to use heavy hydraulic-quality simulations during the monitoring stage. In fact, the method can be used as a preprocessing step by any detector in order to help dealing with multiple quality sensors and to avoid false alarms due to operating changes. The proposed approach is illustrated on a large real-world network in France and the experimental results are very promising

Aquatic invasive species vector management: challenges and practical solutions on the eve of new global shipping regulations

A new world standard for ballast water management (IMO-D2) will be enforced commencing September 2017. This thesis aims to achieve required final population abundances for target organisms. In chapter 2, I tested synergy effects with two ballast water treatments (chlorination and ballast water exchange). Chapter 3 evaluated the number and volume of samples required to achieve defined error rates. Chapter 4 estimated potential production and exposure to disinfection by-products that may occur when chlorine-treating ballast water. Shipboard trials were carried out en route from Canada to Brazil with sampling carried out using a multiport ballast-tank sampling installation designed for these experiments, followed by statistical modeling and simulation for accuracy determination. Bench experiments for by-product formation were carried out with water samples collected from the same origin ports and a ballast tank to mimic water salinity and natural organic matter content. By-products were analyzed over time to determine potential exposure of vessel personnel. Combined treatment performed equal or better than each treatment alone. Synergistic effects were found for Escherichia coli resulting in greatest reductions when treatments were combined. Antagonistic effects (i.e. less than additive) were detected for phytoplankton and coliform bacteria, possibly due to replenishment of individuals after ballast water exchange. Synergistic effects could not be assessed for zooplankton due to complete elimination of viable individuals in all chlorine treatments. Multiport sampling reduced variability from within-tank aggregation. As volume and replicate number increased, error rates decreased. The best tradeoff for accuracy, precision and practicality was obtained using 1m3 ballast samples. Concerns for potential exposure to chemical treatment by-products for vessel personnel were justified, as single-pulse dosing can lead to significant production of harmful trihalomethane by-products, particularly in brackish ballast water with greater natural organic content, but also for marine and freshwater ballast supplemented with organic content. Freshwater chemical by-product levels were lowest for all treatments examined. Meeting performance-based ballast water effluent standards starting in 2017 will be challenging. My thesis demonstrates that sample sizes for effluent compliance testing should be substantial (1 m3), and that combinations of treatments may offer the greatest opportunities for reducing target organism abundances to values below permissible thresholds

Access to safe and year round functional water: an estimation of coverage for three central regions in Tanzania

Water Point Mapping has been extensively used in Tanzania. An enhanced approach, including quality and seasonality of water points has been recently applied in Same District, Tanzania. This paper shows the results of extrapolating the influence of Water Quality and Seasonality in access to water in three central regions of Tanzania,: Dodoma, Tabora and Singida, covering a rural population of 4.5 million, in three statistical scenarios. Influence is assessed by type of water point. The most probable scenario shows that 56% of all rural population served by functional improved water points would be drinking unsafe water from improved water points. Conclusions highlight that the assumption that improved water points provide safe and sustainable water must be revised. More flexible policies towards service provision and revised indicators to track sector evolution should be adopted

Evaluating the Chemical and Biological Stability of Finished Waters Blended for Direct Potable Reuse in a Simulated Distribution System

This work evaluated the impacts of blending several different high grade recycled waters with conventional source waters for direct potable reuse (DPR) applications. Bench-scale laboratory tests were conducted for recycled water-source water blends from four participating facilities that have either considered adopting DPR or have already implemented DPR as a feasible approach to overcome water scarcity. The chemical and biological stability of the finished waters was investigated after pipe rig incubation to simulate the quality of blended waters that had aged in a potable water distribution system. The effects of blend ratio, reclaimed water treatment, and source water quality were evaluated to understand disinfection by-product (DBP) yields, generation of metal corrosion products, and changes in bacterial densities in the effluents collected from the pipe rigs. Blending higher proportions of reverse osmosis (RO)-treated water reduced Total Organic Carbon (TOC) concentrations, which resulted in lower effluent Trihalomethane (THM) concentrations. Increased THM formation occurred in the ozone-biofiltered blends from Utility 2, resulting in concentrations exceeding the U.S. Environmental Protection Agency (USEPA) Maximum Contaminant Limit (MCL) of 0.08 mg/L. Elevated concentrations of THMs were associated with both the high concentration of organic precursors present, and the use of chlorine during secondary disinfection. Total lead concentrations exceeding the 15 g/L EPA action level were generally measured in samples with more negative Langelier Saturation Index (LSI) values. Regression analysis showed that the relationship between pipe rig effluent lead and LSI of the finished waters was significant at a 99% confidence level (p\u3c0.01). For all utilities, pipe rig effluent for RO-treated blends typically contained higher effluent lead and copper concentrations compared to ozone-biofiltered blends; however effluent copper concentrations did not exceed the 1.3 mg/L action level. Corrosion potential of the RO-treated surface water blend from Utility 4 was presumably controlled when zinc orthophosphate was added as a corrosion inhibitor. Biological Activity Reaction Tests (BART™) results indicated that the sulfate reducing bacteria and the slime forming bacteria were the most predominant groups of microorganisms that appeared at the beginning of the reaction period (1-2 days). The results from this study can help advise drinking water facilities in selecting appropriate source waters and optimal blend ratios to augment water portfolios, while conforming to Safe Drinking Water Act regulations that safeguard public health