Sensor setpoints that ensure compliance with microbial water quality targets for membrane bioreactor and chlorination treatment in on-site water reuse systems

Widespread implementation of on-site water reuse systems is hindered by the limited ability to ensure the level of treatment and protection of human health during operation. In this study, we tested the ability of five commercially available online sensors (free chlorine (FC), oxidation-reduction potential (ORP), pH, turbidity, UV absorbance at 254 nm) to predict the microbial water quality in membrane bioreactors followed by chlorination using logistic regression-based and mechanism-based models. The microbial water quality was assessed in terms of removal of enteric bacteria from the wastewater, removal of enteric viruses, and regrowth of bacteria in the treated water. We found that FC and ORP alone could predict the microbial water quality well, with ORP-based models generally performing better. We further observed that prediction accuracy did not increase when data from multiple sensors were integrated. We propose a methodology to link online sensor measurements to risk-based water quality targets, providing operation setpoints protective of human health for specific combinations of wastewaters and reuse applications. For instance, we recommend a minimum ORP of 705 mV to ensure a virus log-removal of 5, and an ORP of 765 mV for a log-removal of 6. These setpoints were selected to ensure that the percentage of events where the water is predicted to meet the quality target but it does not remains below 5%. Such a systematic approach to set sensor setpoints could be used in the development of water reuse guidelines and regulations that aim to cover a range of reuse applications with differential risks to human health. © 2022 The Author(s

A study of platinum, palladium, bismuth, copper, and silver for the potentiometric determination of chlorine

This research was undertaken to determine which metals would be suitable to be used as electrodes for the determination of the concentration of chlorine in aqueous solutions at various pH levels. Platinum, palladium, bismuth, copper and silver electrodes were constructed and tested to determine their applicability for measuring the concentration of chlorine in drinking water, waste water treatment plant effluent, and swimming pools. Buffer solutions were used which varied in pH from 7 to 8, and in cHorine concentration from 0 to 10 ppm. In addition, the potential variation over time was observed for each electrode in the solutions. Platinum, palladium, and copper were found the most appropriate metals for the potentiometric determination of chlorine. The data obtained using these electrodes conformed with Nernstian theory. In addition, the response for palladium appeared to be affected by a variation of pH

Towards a commerical microelectrode array based sensor for improved chlorine detection.

The commercial development of a disposable aqueous chlorine sensor based on a novel microelectrode array fabrication process is described. Non-conducting poly(o-phenylenediamine) films are firstly used to passivate conductive surfaces. Ultrasonic ablation of passivated electrode assemblies then results in the formation of a plurality of wells to expose the underlying conductive substrate, thereby forming a microelectrode array. Microelectrode arrays produced in this manner can be exploited within many electrochemical sensing applications; however, portable aqueous chlorine detection has been selected by Microarray Limited (the industrial sponsors of this project) as a primary vehicle for launching its generic production technology. The scale of microelectrode array production has been extended from that of individual gold sputtercoated glass slide electrodes - to the simultaneous production of hundreds of low-cost screen printed carbon-ink based sensors. A focus has been directed at all stages towards permitting the cost-effective large-scale mass production of sensors with a view to challenging existing portable aqueous chlorine measurement technologies both in terms of performance and unit cost. Based on volume batches of 250,000, it has been calculated that Microarray Limited sensors can be manufactured for a unit cost of approximately 2.5 pence, sufficiently low to provide scope for a competitive yet profitable sale price. The Microarray Limited aqueous chlorine detection system has improved the limit of detection from 0.01 ppm to 0.005 ppm total chlorine without sacrificing accuracy. Furthermore, this novel approach to aqueous chlorine detection offers numerous key benefits to the customer including reduced testing time, a more straightforward operation and the elimination of harmful reagents. Product development has been described from an initial concept through to a pre-production phase. The development of an innovative generic sensor packaging technology is also described

Developing Multi-Scale Models for Water Quality Management in Drinking Water Distribution Systems

Drinking water supply systems belong to the group of critical infrastructure systems that support the socioeconomic development of our modern societies. In addition, drinking water infrastructure plays a key role in the protection of public health by providing a common access to clean and safe water for all our municipal, industrial, and firefighting purposes. Yet, in the United States, much of our national water infrastructure is now approaching the end of its useful life while investments in its replacement and rehabilitation have been consistently inadequate. Furthermore, the aging water infrastructure has often been operated empirically, and the embracement of modern technologies in infrastructure monitoring and management has been limited. Deterioration of the water infrastructure and poor water quality management practices both have serious impacts on public health due to the increased likelihood of contamination events and waterborne disease outbreaks. Water quality reaching the consumers’ taps is largely dependent on a group of physical, chemical, and biological interactions that take place as the water transports through the pipes of the distribution system and inside premise plumbing. These interactions include the decay of disinfectant residuals, the formation of disinfection by-products (DBPs), the corrosion of pipe materials, and the growth and accumulation of microbial species. In addition, the highly dynamic nature of the system’s hydraulics adds another layer of complexity as they control the fate and transport of the various constituents. On the other hand, the huge scale of water distribution systems contributes dramatically to this deterioration mainly due to the long transport times between treatment and consumption points. Hence, utilities face a considerable challenge to efficiently manage the water quality in their aging distribution systems, and to stay in compliance with all regulatory standards. By integrating on-line monitoring with real-time simulation and control, smart water networks offer a promising paradigm shift to the way utilities manage water quality in their systems. Yet, multiple scientific gaps and engineering challenges still stand in the way towards the successful implementation of such advanced systems. In general, a fundamental understanding of the different physical, chemical, and biological processes that control the water quality is a crucial first step towards developing useful modeling tools. Furthermore, water quality models need to be accurate; to properly simulate the concentrations of the different constituents at the points of consumption, and fast; to allow their implementation in real-time optimization algorithms that sample different operational scenarios in real-time. On-line water quality monitoring tools need be both reliable and inexpensive to enable the ubiquitous surveillance of the system at all times. The main objective of this dissertation is to create advanced computational tools for water quality management in water distribution systems through the development and application of a multi-scale modeling framework. Since the above-mentioned interactions take place at different length and time scales, this work aims at developing computational models that are capable of providing the best description of each of the processes of interest by properly simulating each of its underlying phenomena at its appropriate scale of resolution. Molecular scale modeling using tools of ab-initio quantum chemical calculations and molecular dynamics simulations is employed to provide detailed descriptions of the chemical reactions happening at the atomistic level with the aim of investigating reaction mechanisms and developing novel materials for environmental sensing. Continuum scale reactive-transport models are developed for simulating the spatial and temporal distributions of the different compounds at the pipe level considering the effects of the dynamic hydraulics in the system driven by the spatiotemporal variability in water demands. System scale models are designed to optimize the operation of the different elements of the system by performing large-scale simulations coupled with optimization algorithms to identify the optimal operational strategies as a basis for accurate decision-making and superior water quality management. In conclusion, the computational models developed in this study can either be implemented as stand-alone tools for simulating the fundamental processes dictating the water quality at different scales of resolution, or be integrated into a unified framework in which information from the small scale models are propagated into the larger scale models to render a high fidelity representation of these processes

ADVANCED MODELING AND EFFICIENT OPTIMIZATION METHODS FOR REAL-TIME RESPONSE IN WATER NETWORKS

In response to a contamination incident in water distribution networks, effective mitigation procedures must be planned. Disinfectant booster stations can be used to neutralize a variety of contaminant and protect the public. In this thesis, two methods are proposed for the optimal placement of booster stations. Since the contaminant species is unknown a priori, these two methods differ in how they model the unknown reaction between the contaminant and the disinfectant. Both methods employ Mixed-Integer Linear Programming to minimize the expected impact over a large set of potential contamination scenarios that consider the uncertainty in the location and time of the incident. To make the optimal booster placement problem tractable for realistic large-scale networks, we exploit the symmetry in the problem structure to drastically reduce the problem size. The results highlight the effectiveness of booster stations in reducing the overall impact on the population, which is measured using two different metrics - mass of contaminant consumed, and population dosed above a cumulative mass threshold. Additionally, we also study the importance of various factors that influence the performance of disinfectant booster stations (e.g., sensor placement, contaminant reactivity and toxicity, etc.)

Total Water Management System

The purpose of this pilot project is to embark on a total water management system (TWMS) that enables the efficient and effective management of water by addressing both quantity and quality aspects through real time water quality monitoring, water usage monitoring and water leakage monitoring in water distribution network. TWMS is a previous project embarked on by Universiti Teknologi PERONAS (UTP) research community, which is a wireless sensor network (WSN) testbed set up in one of the research laboratories in UTP. In this project, the major work shall focus on implementing a wireless solution in UTP students' villages, to provide a WSN data collection for monitoring and analysis purposes hence the objective is to find an optimal water management solution. The targeted monitoring and control setup would be the wash rooms located at the selected levels and selected houses of each male and female village. Wireless sensors that are installed on the strategic water pipes will be used to measure the water usage, water leakage, and water quality. All data collected would be transmitted automatically to a lab server for storage, archive, and analysis. Command and control signaling can be transmitted wirelessly to control the possible leakages. The outcome of this project shall provide vital statistics and information on the managing and control of water losses, which ultimately may contribute to the improvement of the sustainability of clean water supply and distribution. Moreover this project might provide a platform for wireless sensor technology to become a strategic enabler for a total water management syste

2016 Annex to the Model Aquatic Health Code : scientific rationale. 2nd edition, July 2016.

Posted on 07/18/2016This information is distributed solely as guidance for the purpose of assisting state and local health departments, aquatic facility inspection programs, building officials, the aquatics sector, and other interested parties in improving the health and safety at public aquatic facilities. This document does not address all health and safety concerns associated with its use. It is the responsibility of the user of this document to establish appropriate health and safety practices and determine the applicability of regulatory limitations prior to each use.The Model Aquatic Health Code (MAHC) is a set of voluntary guidelines based on science and best practices that were developed to help programs that regulate public aquatic facilities reduce the risk of disease, injury, and drowning in their communities. The MAHC is a leap forward from the Centers for Disease Control and Prevention\u2019s (CDC) operational and technical manuals published in 1959, 1976, and 1981 and a logical progression of CDC\u2019s Healthy Swimming Program started in 2001. The 2016 MAHC underscores CDC\u2019s long-term involvement and commitment to improving aquatic health and safety. The MAHC guidance document stemmed from concern about the increasing number of pool-associated outbreaks starting in the mid-1990s. Creation of the MAHC was the major recommendation of a 2005 national workshop held in Atlanta, Georgia charged with developing recommendations to reduce these outbreaks. Federal, state, and local public health officials and the aquatics sector formed an unprecedented collaboration to create the MAHC. The MAHC will be regularly updated using input from a national stakeholder partnership called the Council for the Model Aquatic Health Code (CMAHC). The CMAHC was formed to keep the MAHC up to date and current with the latest advances in the aquatics industry while also responding to public health reports of disease and injury. The partnership hopes this truly will lead to achieving the MAHC vision of \u201cHealthy and Safe Aquatic Experiences for Everyone\u201d in the future.The 2016 MAHC utilized the first time CMAHC conference process to collect, assess, and relay MAHC Change Request recommendations to CDC. The first CMAHC Vote on the Code Biennial Conference was held October 6-7, 2015 in Phoenix Arizona, a little over one year after CDC\u2019s release of the 2014 MAHC, 1st Edition. CDC utilized CMAHC\u2019s input to revise the MAHC and plans to utilize the CMAHC conference process to update future versions of the MAHC.CS264311B2016-mahc-annex-final.pdfSupersede

The Effects of Tank Operation and Design Characteristics on Water Quality in Distribution System Storage Tanks

From the Executive Summary Background: Regional water systems utilize storage facilities to meet demand variations and pressure requirements of their systems. These storage facilities drain and fill in response to system water demands and water level control settings. Storage tanks are typically placed in strategic locations to maintain a consistent pressure in the distribution system. Storage facilities should be designed and operated such that the water is mixed to prevent stagnant water (old water that remains in the tank for an extended period). Stagnant water can lead to water quality issues, such as low disinfectant residuals, potential for microbial contamination, disinfectant by-product formation, and nitrification in chloraminated waters. Many tanks have been built without consideration of mixing. These tanks might have a single inlet/outlet, high height to diameter ratio, or have other design characteristics that do not promote mixing. Whether by design or not, tanks without artificial mixing depend upon movement of water during the filling process to mix the tank. A wide array of storage tank types and geometries are utilized in South Dakota’s regional rural water systems. Greater understanding of the relationships of these tank characteristics on stored water quality would enable water systems to optimize the design and operation of their tanks. Objective of Study:The objective of this study was to examine the impacts of tank design and operation on mixing and water quality in storage tanks in South Dakota’s regional rural water systems. This objective was met through a literature review, a survey of system characteristics and evaluation of water quality data obtained from several storage tanks

2016 Annex to the Model Aquatic Health Code : scientific rationale with changes highlighted. 2nd edition, July 2016.

Posted on 07/18/2016This information is distributed solely as guidance for the purpose of assisting state and local health departments, aquatic facility inspection programs, building officials, the aquatics sector, and other interested parties in improving the health and safety at public aquatic facilities. This document does not address all health and safety concerns associated with its use. It is the responsibility of the user of this document to establish appropriate health and safety practices and determine the applicability of regulatory limitations prior to each use.The Model Aquatic Health Code (MAHC) is a set of voluntary guidelines based on science and best practices that were developed to help programs that regulate public aquatic facilities reduce the risk of disease, injury, and drowning in their communities. The MAHC is a leap forward from the Centers for Disease Control and Prevention\ue2\u20ac\u2122s (CDC) operational and technical manuals published in 1959, 1976, and 1981 and a logical progression of CDC\ue2\u20ac\u2122s Healthy Swimming Program started in 2001. The 2016 MAHC underscores CDC\ue2\u20ac\u2122s long-term involvement and commitment to improving aquatic health and safety. The MAHC guidance document stemmed from concern about the increasing number of pool-associated outbreaks starting in the mid-1990s. Creation of the MAHC was the major recommendation of a 2005 national workshop held in Atlanta, Georgia charged with developing recommendations to reduce these outbreaks. Federal, state, and local public health officials and the aquatics sector formed an unprecedented collaboration to create the MAHC. The MAHC will be regularly updated using input from a national stakeholder partnership called the Council for the Model Aquatic Health Code (CMAHC). The CMAHC was formed to keep the MAHC up to date and current with the latest advances in the aquatics industry while also responding to public health reports of disease and injury. The partnership hopes this truly will lead to achieving the MAHC vision of \ue2\u20ac\u153Healthy and Safe Aquatic Experiences for Everyone\ue2\u20ac? in the future.The 2016 MAHC utilized the first time CMAHC conference process to collect, assess, and relay MAHC Change Request recommendations to CDC. The first CMAHC Vote on the Code Biennial Conference was held October 6-7, 2015 in Phoenix Arizona, a little over one year after CDC\ue2\u20ac\u2122s release of the 2014 MAHC, 1st Edition. CDC utilized CMAHC\ue2\u20ac\u2122s input to revise the MAHC and plans to utilize the CMAHC conference process to update future versions of the MAHC.CS264311B2016-mahc-annex-with-changes-highlighted.pd

Best Environmental Management Practice in the Tourism Sector

The tourism sector has a large potential to reduce its environmental impacts and many measures are already effectively implemented by companies of this sector. This document describes what are the best practices employed by frontrunners in all aspects under their direct control or on which they have a considerable influence. They cover cross-cutting issues, destination management, tour operators and travel agents, water and energy consumption and waste production in accommodation, restaurant and hotel kitchens, and campsites management. The document also contains sector-specific environmental performance indicators and benchmarks of excellence. These can be used by all the actors involved in the tourism sector to monitor their environmental performance and to benchmark it against the performance of frontrunners in each given specific area. Overall, this document aims at supporting all actors in the tourism sector who intend to improve their environmental performance and seek for reliable and proven information on how best to do it.JRC.J.5-Sustainable Production and Consumptio