Small Water Systems Research Articles

Evaluation Of Transport Mechanism Of Contaminant Particles In Small Water Systems In Poland

Abstract The change in water quality in small water systems is strongly affected by sediment particles. Their transport, deposition and re-suspension due to variability in water demand has a significant impact on the change in water quality. Two significant mechanism of deposit transport and deposition i.e. turbophoresis and turbulent diffusion have been described in the literature. The paper presents the mechanisms of turbophoresis and turbulent diffusion. These phenomena have an impact on the quality of water in small water systems. The aim of the study is to propose procedures of identifying areas of mechanism of particle movement and their accumulation in small water system networks. Simulation of the flow of small water-pipe network at Niewiesz was used for the study. That water pipeline is situated in the central Poland. Many rural areas in Poland have a similar architecture. Modeling of movement of contaminant in close wall areas in pipelines is presented. The article presents the discussion concerning the areas where the mechanisms of turbophoresis and turbulent diffusion occur in the transport of solid particles in water supply systems. The relations between deposition and transporting of particles in turbulent flows depend on a number of parameters, including: particle size, localization of particles in the pipe (at given time), as well as the turbulence of flow. These parameters change depending on the water demand. The type of these changes depends on pipe diameters, material from which the pipes and the fittings are made, water demand and initial quality of water.

Using Data Mining to Understand Drinking Water Advisories in Small Water Systems: a Case Study of Ontario First Nations Drinking Water Supplies

Although access to safe drinking water is widely assumed to be universal, small drinking water systems in many countries continue to experience an unacceptably large number of drinking water advisories (DWAs). The goal of this research is to describe novel data mining tools that identify the factors contributing to DWAs in small drinking water systems. A dataset containing information related to First Nations drinking water systems in the Province of Ontario, Canada is used for the case study. A decision tree classifier (one of the fastest and most versatile predictive modeling algorithms currently available for data mining) visually maps out the relationship of system characteristics (e.g., source water, system age, and operator certification) to DWA likelihood. The developed model achieves an overall accuracy of 71 % during repeated cross-validation of predictive performance and is of utility when prioritizing future expenditures aimed at proactively reducing the risk of delivering compromised water.

Climate Change Adaptation Planning for Small Water Systems

Small systems and utilities with limited resources can use this stepwise guide to identify, analyze, and rank system‐specific options for adapting to climate change.

Providing water services at scale: how to move from unsustainable assistance to sustainable development?

This article presents the results of a study of water service performance in four small towns in the Sahel Region in Burkina Faso. It shows that water supplied via small piped water systems to tap stands is cheaper per user than water supplied via hand pumps as well as providing better quality service. The comparison of life-cycle costs highlights that the cost of supporting the organisation and management of hand pump services disqualifies this type of access on an economic level. Furthermore, comparison of the levels of service actually delivered to the people shows that piped water systems meet the demand and can have a positive impact on development, whereas hand pumps are part of a survival-oriented approach that is dependent on international assistance.

Short-term spatial and temporal variability of disinfection by-product occurrence in small drinking water systems

Disinfection by-products (DBPs) constitute a large family of compounds. Trihalomethanes and haloacetic acids are regulated in various countries, but most DBPs are not. Monitoring DBPs can be delicate, especially for small systems, because various factors influence their formation and speciation. Short-term variations of DBPs can be important and particularly difficult for small systems to handle because they require robust treatment and operation processes. According to our knowledge, for the first time, our study covers the short-term variability of regulated and non-regulated DBP occurrence in small systems in the summer. An intensive sampling program was carried out in six small systems in Canada. Systems in the provinces of Newfoundland and Labrador and Quebec were sampled daily at the water treatment plant and at six different locations along the distribution system. Five DBP families were studied: trihalomethanes, haloacetic acids, haloacetonitriles, halonitromethanes and haloketones. Results show that there were considerable variations in DBP levels from week to week during the month of study and even from day to day within the week. On a daily basis, DBP levels can fluctuate by 22% to 96%. Likewise, the large number of sampling locations served to observe DBP variations along the distribution system. Observations revealed some degradation and decomposition of non-regulated DBPs never before studied in small systems that are associated with the difficulty these systems experience in maintaining adequate levels of residual disinfectant. Finally, this study reveals that the short term temporal variability of DBPs is also influenced by spatial location along the distribution system. In the short term, DBP levels can fluctuate by 23% at the beginning of the system, compared to 40% at the end. Thus, spatial and temporal variations of DBPs in the short term may make it difficult to select representative locations and periods for DBP monitoring purposes in small systems.

Cryptosporidium in small water systems in Puerto Rico: a pilot study.

A pilot study was undertaken to investigate the occurrence of Cryptosporidium in four very small drinking water systems supplying communities in rural Puerto Rico. Water samples (40 L) were collected and oocysts were concentrated by calcium carbonate flocculation, recovered by immunomagnetic separation and detected by immunofluorescence microscopy. Cryptosporidium oocysts were identified in all four systems. This is the first report of evidence of the potential public health risk from this chlorine-resistant pathogen in Puerto Rican small water systems. Further work is warranted to fully assess the health risks that Cryptosporidium and other protozoa pose to populations served by community-managed small drinking water systems.

Treatment, residual chlorine and season as factors affecting variability of trihalomethanes in small drinking water systems

Seasonal variability in source water can lead to challenges for drinking water providers related to operational optimization and process control in treatment facilities. The objective of this study is to investigate seasonal variability of water quality in municipal small water systems (<3000 residents) supplied by surface waters. Residual chlorine and trihalomethanes (THM) were measured over seven years (2003–2009). Comparisons are made within each system over time, as well as between systems according to the type of their treatment technologies. THM concentrations are generally higher in the summer and autumn. The seasonal variability was generally more pronounced in systems using chlorination plus additional treatment. Chloroform, total THM (TTHM) and residual chlorine concentrations were generally lower in systems using chlorination plus additional treatment. Conversely, brominated THM concentrations were higher in systems using additional treatment. Residual chlorine was highest in the winter and lowest in the spring and summer. Seasonal variations were most pronounced for residual chlorine in systems with additional treatment. There was generally poor correlation between THM concentrations and concentrations of residual chlorine. Further study with these data will be beneficial in finding determinants and indicators for both quantity and variability of disinfection byproducts and other water quality parameters.

The costs of small drinking water systems removing arsenic from groundwater

The US Environmental Protection Agency (EPA) conducted an Arsenic Demonstration Program whereby the Agency purchased, installed, and evaluated the performance and cost of 50 small water arsenic removal treatment systems in the USA. A major goal of the program was to collect high-quality cost data (capital and operational and maintenance (O&M)) from the long-term operation (1–4 years) of these systems. The technologies consisted of adsorptive media (AM), iron removal (IR), coagulation/filtration (C/F), ion exchange (IX), reverse osmosis, and point-of-use devices, which reduced the arsenic to less than the EPA maximum contaminant level of 10 μg/L. This paper presents the capital and O&M cost of 48 treatment systems ranging in size from 10 to 770 gal/min (gpm) (38–2,915 L/min). The capital cost of the systems ranged from $477 to $6,171 per gpm ($126–$1,632 per L/min) of design flow and the O&M cost from $0.07 to $22.88 per 1,000 gal ($0.02–$6.05 per 1,000 L) of treated water. AM had a lower capital, but a higher O&M cost than IR, C/F, and IX. The media replacement cost for the AM systems averaged 80% of the O&M cost and was the main cause of the higher O&M cost of the AM systems.

Permanent Magnet Machine Can Be a Vibration Sensor for Itself

This article presents a new vibration diagnostic method designed to (PM) machines with permanent magnets. Those devices are commonly used in small wind and water systems or vehicles drives. The author’s method is very innovative and unique. Specific structural properties of PM machines are used in this method electromotive force (EMF) generated due to vibrations. There was analysed number of publications which describe vibration diagnostic methods and tests of electrical PM machines and there was no method found to determine the technical condition of such machine basing on their own signals. In this article will be discussed: the method genesis, the similarity of machines with permanent magnet to vibration sensor and simulation and laboratory tests results. The method of determination the technical condition of electrical machine with permanent magnets basing on its own signals is the subject of patent application and it is the main thesis of author’s doctoral dissertation. Keywords—Electrical vehicle, generator, permanent magnet, traction drive, vibrations.

Permanent Magnet Machine Can Be a Vibration Sensor for Itself

This article presents a new vibration diagnostic method designed to (PM) machines with permanent magnets. Those devices are commonly used in small wind and water systems or vehicles drives. The author’s method is very innovative and unique. Specific structural properties of PM machines are used in this method electromotive force (EMF) generated due to vibrations. There was analysed number of publications which describe vibration diagnostic methods and tests of electrical PM machines and there was no method found to determine the technical condition of such machine basing on their own signals. In this article will be discussed: the method genesis, the similarity of machines with permanent magnet to vibration sensor and simulation and laboratory tests results. The method of determination the technical condition of electrical machine with permanent magnets basing on its own signals is the subject of patent application and it is the main thesis of author’s doctoral dissertation. Keywords—Electrical vehicle, generator, permanent magnet, traction drive, vibrations.

A Compact, Efficient and Expandable Title 22 Treatment System for Small Water Systems

A Compact, Efficient and Expandable Title 22 Treatment System for Small Water Systems

Optimization and economic analysis of small scale nanofiltration and reverse osmosis brackish water system powered by photovoltaics

Integration of renewable energy with desalination technologies is a strongly emerging field in many regions of the world having drinking water and energy crisis. This study presents the results of a techno-economical investigation of a small scale, photovoltaic (PV) powered hybrid nanofiltration (NF) and reverse osmosis (RO) membrane system for the brackish water treatment. Optimization experiments of six commercially available small scale RO and NF membranes were carried out using central composite design (CCD) of response surface methodology (RSM). Experiments employing optimized input conditions validate the developed RSM model. Predictive model, using multiple response optimizations, revealed that CSM RO and NF250 membranes showed the optimal efficiency with 20.24% and 18.98% water recovery, 90.22% and 70.64% salt rejection and 17.87 and 9.35kWh/m3 of SEC respectively. Comparison of membranes was also carried out by membrane characterization duly supported by experimental observations. Membrane surface was characterized by AFM, contact angle measurement and FTIR. Hybrid experiments were performed with NF and RO membranes in concentrate and permeate staging configurations. Results also suggested that techno-economic performance of the hybrid PV–NF/RO system was affected by factors like mode of integration of NF and RO membranes, recovery ratio, daily average operating hours and government subsidy.

Occurrence of regulated and non-regulated disinfection by-products in small drinking water systems

The occurrence of regulated and non-regulated disinfection by-products (DBPs) was investigated in the drinking water of small systems in two provinces in Canada, Newfoundland and Labrador (NL) and Quebec (QC), through an intensive sampling program. Sixteen DBPs were studied: four trihalomethanes (THMs), five haloacetic acids (HAAs), four haloacetonitriles (HANs), one halonitromethane, chloropikrin (CPK) and two haloketones (HKs). Average measured concentrations of these compounds were much higher than those reported in the literature for medium and large systems. The measured average value for THMs was 75μgL−1 (Stdv=69μgL−1); HAAs, 77μgL−1 (Stdv=75μgL−1); HANs, 2.5μgL−1 (Stdv=1.8μgL−1); CPK, 0.4μgL−1 (Stdv=0.3μgL−1) and HKs, 6.0μgL−1 (Stdv=4.5μgL−1). The gap (some 10 times difference) between the average levels of regulated DBPs (THMs, HAAs) and non-regulated DBPs (HANs, CPK and HKs) is comparable to that observed in large systems where the occurrence of the same compounds has been reported. Generally, investigated DBPs followed a comparable seasonal evolution during the year: they decreased between the fall and winter and then increased to eventually reach a maximum in late summer. This trend was less observable in NL than in QC. However, observed seasonal fluctuations of DBPs were less considerable than those observed in medium and large systems located in similar temperate environments reported in the literature. Spatial variations from the plant to the extremities were high and comparable to those observed in large systems, which is surprising, considering the smaller size of distribution networks supplying small communities. Generally speaking, the results support the premise that problems associated with implementing treatment that removes DBP precursors in water submitted to chlorination can increase population exposure to these contaminants in small systems.

Nitrate in Potable Water Supplies: Alternative Management Strategies

Nitrate contamination of drinking water sources has become one of the most important water quality concerns across the United States. Nitrate presents unique water treatment challenges and small water systems are particularly affected by the high costs of addressing nitrate impacted supplies. The goal of this investigation was to provide an overview of nitrate treatment options, highlighting the most recent advances and elucidating costs and common problems in application. No single treatment option is ideal for all situations; new technologies continue to be investigated to effectively remove nitrate while limiting cost and maximizing sustainability.

Water compliance challenges: how do Canadian small water systems respond?

Fundamental to community health and well-being is the capacity to access a sustainable supply of safe drinking water. Small community drinking water systems are the most vulnerable to contamination, and struggle to secure the funds necessary to improve water treatment and delivery systems, and meet increasingly stringent drinking water quality regulations. Little is known of the contextual and cultural differences between communities and the impact this has on regulatory compliance. This study explored the experiences and impact of individual actors within seven small community drinking water systems in locations across Canada. Qualitative, in-person interviews were conducted with water operators, consumers, and decision-makers in each community, and these findings were analysed thematically. Findings from the study show that communities approach and align with compliance challenges in three distinct ways: by adopting regulator-provided or regulator-driven solutions, by adopting an existing improvement framework (i.e. regionalization), or through reinvention to address a new issue or concern. Policy-makers looking to align small communities with appropriate water quality goals may benefit from a consideration of these contextual and cultural differences.

PM Electrical Machines Diagnostic: Methods Selected

Abstract—This paper presents a several diagnostic methods designed to electrical machines especially for permanent magnets (PM) machines. Those machines are commonly used in small wind and water systems and vehicles drives. Those methods are preferred by the author in periodic diagnostic of electrical machines. The special attention should be paid to diagnostic method of turn-to-turn insulation and vibrations. Both of those methods were created in Institute of Electrical Drives and Machines Komel. The vibration diagnostic method is the main thesis of author’s doctoral dissertation. This is method of determination the technical condition of PM electrical machine basing on its own signals is the subject of patent application No P.405669. Specific structural properties of machines excited by permanent magnets are used in this method electromotive force (EMF) generated due to vibrations. There was analysed number of publications which describe vibration diagnostic methods and tests of electrical machines with permanent magnets and there was no method found to determine the technical condition of such machine basing on their own signals.

Associations between perceptions of drinking water service delivery and measured drinking water quality in rural Alabama.

Although small, rural water supplies may present elevated microbial risks to consumers in some settings, characterizing exposures through representative point-of-consumption sampling is logistically challenging. In order to evaluate the usefulness of consumer self-reported data in predicting measured water quality and risk factors for contamination, we compared matched consumer interview data with point-of-survey, household water quality and pressure data for 910 households served by 14 small water systems in rural Alabama. Participating households completed one survey that included detailed feedback on two key areas of water service conditions: delivery conditions (intermittent service and low water pressure) and general aesthetic characteristics (taste, odor and color), providing five condition values. Microbial water samples were taken at the point-of-use (from kitchen faucets) and as-delivered from the distribution network (from outside flame-sterilized taps, if available), where pressure was also measured. Water samples were analyzed for free and total chlorine, pH, turbidity, and presence of total coliforms and Escherichia coli. Of the 910 households surveyed, 35% of participants reported experiencing low water pressure, 15% reported intermittent service, and almost 20% reported aesthetic problems (taste, odor or color). Consumer-reported low pressure was associated with lower gauge-measured pressure at taps. While total coliforms (TC) were detected in 17% of outside tap samples and 12% of samples from kitchen faucets, no reported water service conditions or aesthetic characteristics were associated with presence of TC. We conclude that consumer-reported data were of limited utility in predicting potential microbial risks associated with small water supplies in this setting, although consumer feedback on low pressure—a risk factor for contamination—may be relatively reliable and therefore useful in future monitoring efforts.

Experience, training and confidence among small, non-community drinking water system operators in Ontario, Canada.

The water operator plays an important role in water safety; however, little published research exists that has examined this role. The purpose of this study was to develop a greater understanding of the experience, existing knowledge, confidence and future training needs of the small, non-community drinking water operator in Ontario in order to help guide future outreach and training opportunities. A cross-sectional telephone survey of 332 small, non-community drinking water operators in Ontario was conducted in July and August 2011. Survey questions pertained to respondents' experience as operators, formal training, perceived importance of water safety issues, confidence in handling water safety issues, and future training needs. Approximately 16% (54/330) of respondents had one year or less experience as a water operator, and 60% (199/332) reported that being a water operator was not a chosen profession. Only 37% (124/332) of operators reported completing operator training. Respondents reported a preference for online training courses or on-site training (compared with a classroom setting). Low training rates, inexperience, and in certain situations, low confidence, among many small water system operators highlight a need to provide continued support to the development of ongoing training opportunities in this population.

Carbon nanotube composite membranes for small ‘designer’ water treatment systems

Small water systems that serve fewer than a few thousand persons are often less safe and less sustainable than large drinking water systems due to lack of suitable technologies. This ongoing research aims to develop a novel water treatment technology for small communities. By layering structured, functional carbon nanotubes (CNT) onto low pressure membranes (LPMs), composite membranes were prepared to remove different organic and inorganic contaminants from water, including heavy metals, viruses, natural organic matter, and organic micropollutants. The removal efficiencies varied from over 99.9% (for cadmium) to above 60% (for humic substances). A low-cost CNT formed an antifouling layer that removed membrane foulants by depth filtration, thereby extending the membrane filtration cycle over five-fold. When the CNTs were layered inside hollow fiber membranes, superb backwashable properties were observed, allowing the operation of CNT-modified membranes under full-scale treatment conditions. Moreover, a systematic study of CNT rejection by LPMs found that commercially available LPMs efficiently prevented CNT breakthrough, thus ensuring nanosafety of the treated water. By varying the composition and structure of functional CNT layers, energy-efficient composite membranes may be economically produced for designer water treatment systems and applied in small communities.

The roles and effects of safety factors in small system water regulation

For small water systems, complying with drinking water regulations can be costly; the National Rural Water Association has produced several white papers that evaluate these regulations and the conservative assumptions on which they are based.