Are Secondary Disinfectants Performing as Intended?

In many countries, regulations do not require the use of secondary disinfectants to ensure safe drinking water. The water industry may be overly reliant on secondary disinfectants to compensate for less‐than‐ideal treatment and distribution system management. The water industry should evaluate the use of secondary disinfectants to ensure the benefits are realized and that public health goals are being met

Self-Organizing Maps For Knowledge Discovery From Corporate Databases To Develop Risk Based Prioritization For Stagnation

Stagnation or low turnover of water within water distribution systems may result in water quality issues, even for relatively short durations of stagnation / low turnover if other factors such as deteriorated aging pipe infrastructure are present. As leakage management strategies, including the creation of smaller pressure management zones, are implemented increasingly more dead ends are being created within networks and hence potentially there is an increasing risk to water quality due to stagnation / low turnover. This paper presents results of applying data driven tools to the large corporate databases maintained by UK water companies. These databases include multiple information sources such as asset data, regulatory water quality sampling, customer complaints etc. A range of techniques exist for exploring the interrelationships between various types of variables, with a number of studies successfully using Artificial Neural Networks (ANNs) to probe complex data sets. Self Organising Maps (SOMs), are a class of unsupervised ANN that perform dimensionality reduction of the feature space to yield topologically ordered maps, have been used successfully for similar problems to that posed here. Notably for this application, SOM are trained without classes attached in an unsupervised fashion. Training combines competitive learning (learning the position of a data cloud) and co-operative learning (self-organising of neighbourhoods). Specifically, in this application SOMs performed multidimensional data analysis of a case study area (covering a town for an eight year period). The visual output of the SOM analysis provides a rapid and intuitive means of examining covariance between variables and exploring hypotheses for increased understanding. For example, water age (time from system entry, from hydraulic modelling) in combination with high pipe specific residence time and old cast iron pipe were found to be strong explanatory variables. This derived understanding could ultimately be captured in a tool providing risk based prioritisation scores

Energy metrics to evaluate the energy use and performance of water main assets

Managing aging infrastructure has become one of the greatest challenges for water utilities, particularly when faced with selecting the most critical pipes for rehabilitation from among the thousands of candidates. This paper presents a set of novel yet practical energy metrics that quantify energy interactions at the spatial resolution of individual water mains to help utilities identify pipes for rehabilitation. The metrics are demonstrated using a benchmark system and two large, complex systems. The results show that the majority of pipes have good energy performance but that an important minority of outlier pipes have low energy efficiency and high energy losses due to friction and leakage. Pumping and tank operations tend to drive energy efficiency and energy losses in pipes close to water sources, whereas diurnal variation in demand drives energy performance of mains located far away from water sources. The new metrics of energy lost to friction and energy lost to leakage can provide information on energy performance in a pipe that is complementary to the traditional measures of unit head loss and leakage flow

Understanding the costs of investigating coliform and E. coli detections during routine drinking water quality monitoring

Bacteriological failure investigations are crucial in the provision of safe, clean drinking water as part of a process of quality assurance and continual improvement. However, the financial implications of investigating coliform and Escherichia coli failures during routine water quality monitoring are poorly understood in the industry. The investigations for 737 coliform and E. coli failures across five UK water companies were analysed in this paper. The principal components of investigation costs were staff hours worked, re-samples collected, transportation, and special investigatory activities related to the sample collection location. The average investigation costs ranged from £575 for a customer tap failure to £4,775 for a water treatment works finished water failure. These costs were compared to predictions for US utilities under the Revised Total Coliform Rule. Improved understanding of the financial and staffing implications of investigating bacteriological failures can be used to budget operational expenditures and justify increased funding for preventive strategies

Interpreting and estimating the risk of iron failures

Metals and particulates accumulate in the distribution system and are mobilised by hydraulic events which can result in discolouration and exceedance of regulatory standards. Traditional decision tools for targeting preventive work are single parameter, based for example on proportion of unlined iron pipe or the number of customer contacts per district metering area (DMA). We show that this approach is too simplistic and propose a multivariate Decision Tree process, using the Random Under-Sampling ensemble method. The outputs gave a classification of High or Low risk per DMA. Initial findings demonstrate an 80 % success rate in identifying high risk DMAs across the supply area for a UK water company

The Broad-Brush Survey Approach. A set of methods for rapid qualitative community assessment

Using a combination of qualitative data collection methods to collect data rapidly from a place on a particular topic is not a novel idea. Rapid participatory and qualitative appraisal approaches have been used in many different settings for the past 40 years, with the influential scholar Robert Chambers, and those he worked with, doing much to shape the practice from the 1970s. The methods spread beyond a rural, agriculture focus (Chambers, 1994) to embrace urban settings and the assessment of health and other areas of interest as well as settings in the Global North as well as South (Annett and Rifkin, 1995, Murray et al., 1994). I first used these approaches in the 1980s, while working in the Annapurna foothills in Nepal at an agricultural research station. We established the practice of a one week data collection exercise, which we called a `Combined Trek’ where a group of scientists from different disciplines, including me – a social anthropologist – systematically collected information using interviews, observations and discussions in a village and the surrounding area – working closely with the local people. Our purpose was to inform future agricultural interventions, building from what people were already doing. Cecilia Vindrola-Padros and Ginger Johnson (2020) detail in a review article how different qualitative methods have been adapted to be used to collect data rapidly. The need for speed, as they explain, has been a response to the increasing pressure many of us are under to deliver study findings quickly. Their review sets out how conventional methods have been adapted to be used rapidly in different settings. Among the combination of methods that they describe is the `rapid ethnographic assessment’. This assessment approach has grown as a response of anthropologists to pressure to produce results far more quickly that more conventional ethnographic approaches would allow. This set of methods is described in detail in the recent manual produced by Sangaramoorthy and Kroeger (2020). We are not, therefore, claiming that the approach set out in this manual is particularly novel nor indeed unique. The Broad Brush Survey, described in this manual is an approach originally developed by Valdo Pons (1993, 1996) and further developed and popularized through the work of Sandra Wallman (1996), which can be used to capture both the landscape and ‘feel’ of a community and the people in it. The research findings can be used to shape further investigators or interventions to address the problem at hand in a useful and practical manner rapidly, succinctly and systematically. This `Broad Brush Survey’ approach manual is, therefore, a contribution to the burgeoning literature on methods for rapid qualitative data collection methods and assessment. The use of the word ‘survey’ in the title of the set of methods may be perplexing to those who consider the term to be synonymous with `questionnaire’. This 6 is not the way we use the word – the Oxford English Dictionary offers several definitions of word `survey’, which include `the act of viewing, examining, or inspecting in detail [...] for some specific purpose’ and `the, or an, act of looking at something as a whole from a commanding position; a general or comprehensive look’. Both definitions convey the sense of our intention: to engage with, and in, a community for a short but concentrated period of time, seeking quickly, but thoroughly, to take a comprehensive look at the place for a specific purpose, and document the place at that moment in time. As we explain in the first chapter, the approach is systematic with a defined sequence of qualitative data collection methods, which gradually allows the user to build an understanding of place and people. The combination of methods used, however, is not set in stone and can be adapted to suit the purpose at hand. As such we hope that this manual serves as a guide to the possibilities which using this approach can offer both for those working in interdisciplinary projects as well as those from anthropology and sociology, for example, laying the groundwork for in-depth longitudinal research

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Optimization of the Operation of a Multiple Reservoir System using 0,1 Mixed Integer Programming

The multiple reservoir system owned by the Orange Water and Sewer Authority consists of three separate, interconnected reservoirs. The operation of this system is complex, with four pathways by which water can reach the water treatment plant in Carrboro, NC. The physical characteristics of the system led to the choice of 0, 1 mixed integer programming as the technique used to optimize operation with respect to pumping costs. The model was formulated with pumped flows, storages in the reservoirs and downstream spillages as decision variables. A linear release rule and chance constraints were applied to reduce the dimensionality of the problem. Input parameters, such as inflows, pumping prices and demands for water, were evaluated for use with the model using actual operational data. A set of input parameters characteristic of the present operating conditions was chosen to represent a baseline solution, which was used for comparison in the sensitivity analysis. Through this analysis, the operation of the system was found to depend on the working volume of the reservoirs as well as the inflows. This information led to the development of an operating rule for the system under three different inflow conditions: wet, average and dry years. The model output can also be used as a tool for economic analysis to identify cost-saving measures under both present and future operating conditions.Master of Science in Environmental Engineerin