Use Of Potable Water Research Articles

Occurrence and human exposure assessment of parabens in water sources in Osun State, Nigeria

Parabens are chemicals extensively used in pharmaceuticals, cosmetics, personal hygiene and food products as preservatives. They are classified as emerging contaminants with endocrine-disrupting capability. In this study, the concentrations of Methylparaben (MeP), Ethylparaben (EtP), Propylparaben (PrP) and Butylparaben (BuP) were obtained from groundwater, surface-water and packaged water samples collected from urban and rural areas of Osun State, Nigeria using HPLC-UV equipment. Data obtained were subjected to descriptive (Mean ± SD), inferential (Kruskal-Wallis test) and multivariate analyses. MeP had the highest average concentration of 163 and 68 μg L−1 in surface water and groundwater respectively while concentrations of MeP, EtP, PrP and BuP were higher than previously reported in other countries. Methylparaben had the highest detection frequencies (88.0 and 50.0%) followed by BuP (69.0 and 50.0%) in surface water and groundwater respectively. No significant difference was observed for concentrations of parabens in groundwater samples in urban and rural sampling sites, suggesting that people living around these sites are equally exposed to any health implications from the use of paraben-polluted potable water. Principal Component Analysis (PCA) data suggest that the pairs MeP & EtP, PrP & BuP (in surface water samples) and MeP, EtP, & PrP (in groundwater samples) are from similar pollution sources. Ecological risk assessment using Algae, Fish, and Daphnia suggests Daphnia as the most sensitive organism while BuP and PrP show the highest health risk. Human exposure assessment showed that higher overall median estimated daily intake (EDI) values for groundwater were observed in infants (1.71 μg kg−1 bw day−1, ∑PBs) compared to toddlers (1.03 μg kg−1 bw day−1, ∑PBs), children (0.64 μg kg−1 bw day−1, ∑PBs), teenagers (0.51 μg kg−1 bw day−1, ∑PBs) and adults (0.62 μg kg−1 bw day−1, ∑PBs). Although these values are below limits set in a few countries, potential bioaccumulation could lead to severe health consequences.

How much potable water is saved by wastewater recycling? Quasi-experimental evidence from California

Recently, California has made large investments in wastewater recycling to replace applications that use potable water. It may be expected that the use of recycled water reduces potable water use, but such an equivalency is not assured. The addition of recycled water infrastructure in a large Californian water district creates a natural experiment where this work tests how recycled water usage affects primary potable water. This is done using econometric methods for causal inference in an observational setting that mirror a randomized control trial (RCT). From 2001 to 2014, a number of public parks were given recycled water infrastructure, while others in those regions remained exclusively on potable supply. A two-way fixed effects regression is used to produce a difference-in-differences estimate of the average treatment effect of recycled water on total and potable water usage. The results indicate that potable water usage is reduced significantly when a park is connected to the recycled water supply. The estimated rate of displacement in the study period is 81.7%, meaning each unit of recycled water use avoided 0.817 units of potable water usage, which implies the connection of parks to recycled water supply increases total water use. The analysis provides, to the best of our knowledge, the first empirical estimate of the water savings claimed by urban water recycling programs, and the first empirical estimate of displacement using quasi-experimental methods. The methodology can be utilized to evaluate the effectiveness of recycling programs around the world.

Water Conservation and Management Practices at the University of Sharjah to Achieve Sustainability Excellence

The University of Sharjah is a leading educational and research institution in the Gulf region. To stimulate the different aspects of sustainability in education and research as well as to ensure the implementation of sustainability concepts throughout the University campus operations, the concept of sustainability circles is implemented. The University being in hot-arid-zone and mostly surrounded by desert terrain relies on unconventional water conservation programs and initiatives such as the use of innovation & technology, reuse and recycling of water, and awareness campaigns. In line with such programs, the use of potable water is limited for hygiene purposes and wastewater generated within the University is reused after treatment to irrigate the vast green spaces through the most efficient irrigation water application systems. Examples of water conservation practices include use of efficient water devices, reuse of treated greywater for toilet flushing at a selected location, water quality monitoring, preservation to conserve water for its intended use, promoting waterless car wash on the campus grounds etc. On-campus water is also conserved through disseminating knowledge and awareness to the University community and beyond through various sustainability related programs and initiatives organized by Sustainability Office for water conservation and environmental protection.

Chemical Characteristics of Flow Driven by Rainfall and Associated Impacts on Shallow Groundwater Quality in a Karst Watershed, Southwest China

Monitoring from 2016 to 2018 was used to investigate seasonal variation of chemical characteristics and define the water quality status within a subsurface river system in a karst region of Southwest China. For this, the water quality index (WQI) and principal component analysis (PCA) were employed. Results showed that baseflow and constituents, i.e., TN, TP, NO2−-N, and SO42− exhibited seasonal variation. Arsenic and selenium were the main pollutants found in the river system of the Houzhai river basin. Total dissolved solids (TDS), pH, selenium, TP, NO2−-N, and TN were obviously impacted by precipitation during the precipitation-derived flow processes. The groundwater quality was categorized as “very poor” throughout the entire monitoring period, with WQI values ranging from 62 to 70. In particular, TN, TP, selenium, and arsenic scores ranged from 80 to 100, which are considered unsuitable for potable water use. In order to ensure the safety of groundwater as a potable water source, administrators must recognize the importance of preventing the cross-contamination of surface water and groundwater to guarantee the safety of water and the health of local residents in karst areas.

AWWA Water Science Author Spotlight

Having recently published an article in AWWA Water Science, Megan Plumlee answered questions from the publication's editor-in-chief, Kenneth L. Mercer, about the research. Real-Time Reverse Osmosis Monitoring for Antiscalant Dose Selection in Advanced Treatment of Wastewater Anditya Rahardianto, Han Gu, Bilal M. Khan, and Megan H. Plumlee Megan Plumlee visits Huntington State Beach in Southern California. Right now our team at the Orange County Water District (OCWD) is especially focused on per- and polyfluoroalkyl substances (PFAS), such as exploring novel treatment methods for removing PFAS from drinking water. We're also studying ways to demonstrate, and therefore get appropriate credit for, enteric virus removal during advanced water purification as part of potable reuse of (waste)water. Broadly speaking, we research topics relevant to our organization. OCWD (Fountain Valley, Calif.) manages a groundwater aquifer and employs potable reuse. Megan (front row, at left) is a member of the Research and Development Department at Orange County Water District in Fountain Valley, Calif. Department staff gather at a holiday luncheon in 2019. I remember fondly my undergraduate chemistry professor and advisor, who passed away recently, Jim Currie of Pacific University. He was humble and kind. He pushed me to apply to a lot of really noteworthy and famous universities to pursue my PhD; I don't think I would have reached so high or been so confident on my own. I ended up at Stanford for my master's and PhD degrees. I thank you—and miss you—Professor Currie. Our best work is through collaborations since people always do better in a team with diverse inputs and different drivers. For this project, we wanted to collaborate with the developer (Noria Water Technologies out of University of California, Los Angeles) on their new and improved technology (RO-SpotlightTM) to explore practical applications of a novel sensor in our treatment plant. The overarching goal is to be able to better manage and address the inevitable fouling and scaling of reverse osmosis membranes through better, real-time data. Because people are only human and don't have computer brains (yet), I think our biggest challenge across all of science and engineering is how to better solve problems via systems-level thinking. Since we aren't connected with a hive mind, I suspect that people are inefficiently working on the “same” problems over and over again in different fields or even the same field. What solutions can we environmental engineers or chemists adopt from, say, medicine or materials science or food science? As we strive to make recycling water for potable use more efficient and therefore less expensive, I hope it will open up the feasibility of this water supply for other communities. Especially now with telecommuting every day and having gotten awfully comfortable with it in my armchair, I am trying to avoid being too sedentary. I walk my dogs every day, prepare nearly all my food from scratch (including bread and oat milk), and I literally run up and down the stairs as much as possible as a sorry form of exercise. To learn more about Megan's research, visit the article online at https://doi.org/10.1002/aws2.1196. This article is part of the Topical Collection on Potable Reuse. Visit https://news.awwa.org/reuse-collection to learn more about this collection.

Public stereotypes of recycled water end uses with different human contact: Evidence from event-related potential (ERP)

Recycled water is an effective way to ease regional water resource shortages and promote environmental protection. The public is a direct user of recycled water, so their attitudes and acceptances are key links in the implementation of recycled water reuse projects. However, in the practical process of the implementation of recycled water reuse projects, the concept is frequently rejected by the public because of the negative perception that it is sourced from sewage. To gain a deeper understanding of this negative perception, this study attempts to take a cognitive neuroscience approach for assessing the stereotypes of recycled water end uses with different human contacts based on a temporal analysis of event-related potentials (ERP) and decision-making data. The results are as follows. First, in general, the stereotypes of recycled water reuse are deeply rooted among the public and are significantly negative. Second, compared with recycled water for car-washing, descriptions of recycled water for potable use with positive adjectives could evoke more significant N400 responses. In other words, the public perceive that recycled water for potable use is harmful, dangerous, and disgusting. Third, for recycled water with different levels of human contact, the negative stereotypes vary greatly. With increasing human contact levels, negative stereotypes will be increasingly enhanced. This study can provide scientific references for the promotion of recycled water end-use projects and optimal allocation of water resources.

Studies on strength parameters of blended self cured concrete with natural and manufactured sand on the impact of fly ash and ground granulated blast furnace slag

Construction companies now use manufactured sand instead of natural river sand in concrete for a day, where the exploration limitation applies to river sand along with the implementation rule. Water, meanwhile, is also the most prevalent aspect of the concrete manufacturing curing process, and it is now scarce for a few days due to a greater rise in human population growth. In contrast to the traditional curing process, self-curing concrete minimizes the use of potable water. In addition to chemical admixture with the mixture, this paper deals with the various studies of fresh and hardened concrete specimens and findings with the self-curing agent mixed with PEG 400 with Fly Ash and GGBFS in different proportions. The results for the various combinations of blended proportions are correlated with the substitution of manufactured sand (M-Sand) with river sand with both ordinary self-curing concrete and mixed self – curing concrete with M30 grade. Attempts have been made to study the properties of blended self – curing concrete with Manufactured Sand.

Studies on strength behaviour of green self cured concrete with ecosand with impact of fly ash and ground granulated blast furnace slag

Construction firms now use artificial sand or else manufactured sand in concrete for a day instead of natural river sand, where the excavation prohibition applies to river sand along with the implementation law. Natural sand or River sand are one of the constituents of concrete taken from a river. The problems of deterioration of the ecosystem and costly and the condition of the natural sand of river is rising day by day. About the Global Natural sand consumption has increased because of excessive use of concrete to ensure a very strong demand for river san, where Eco Sand is necessary to replace natural silica. Potable Water, meanwhile, is also the extremely ubiquitous feature for the concrete production and curing activity, and it is now insufficient for a limited period due to a superior growth in human population growth. Self-curing concrete helps to reduce the use of potable water, in contrast to the traditional curing system. In supplement to chemical admixture with the concrete mixture, this paper deals with the various studies of fresh and hardened concrete specimens with various replacement level of Eco sand and findings with the self-curing agent mixed with PEG 400 with Fly Ash and GGBFS proportioning. The results are correlated with the replacement of Eco sand with river sand with both ordinary self-curing concrete and blended self-curing concrete with M30 grade for the different combinations of blended proportions. Attempts have been made to research with Eco Sand to identify the properties of blended self-curing concrete.

Performance of Two Seashore Paspalum (Paspalum vaginatum Sw.) Varieties Growing in Shallow Green Roof Substrate Depths and Irrigated with Seawater

The continuing decline in global drinking water reserves necessitates finding alternative water sources for turfgrass irrigation, especially in southern semi-arid Mediterranean countries. The aim of the present study was to evaluate the potential of using seawater for irrigating two varieties of seashore paspalum (Paspalum vaginatum Sw.), “Marina” and “Platinum ΤΕ”, growing in shallow green roof substrates, and to determine their recuperative capacity after the termination of the salt stress period. The greenhouse study comprised of 48 lysimeters equipped with extensive green roof layering. Treatments included: (i) two substrate depths (7.5 cm or 15 cm) and (ii) three seawater irrigation regimes (7 mm, 15 mm, or 45 mm every two days). Measurements included the determination of green turf cover (GTC) as well as the leaching fraction (LF) and leachate electrical conductivity (ECL) draining from the lysimeters. It was found that during the 46-d salt stress period, none of the seawater irrigation regimes managed to maintain acceptable GTC levels for both seashore paspalum varieties. Increasing the green roof substrate depth from 7.5 cm to 15 cm resulted in GTC improvement. During the recovery period, the use of potable water as irrigation source improved GTC levels. After 40 d the recovery was complete since GTC exceeded 90% in all treatments for both varieties. Regression curves correlating GTC response to ECL can be used to estimate the leaching requirements of turfgrasses grown in shallow green roof systems when irrigated with saline water.

A participatory system dynamics model to investigate sustainable urban water management in Ebbsfleet Garden City

Growing urban populations, changes in rainfall patterns and ageing infrastructure represent significant challenges for urban water management (UWM). There is a critical need for research into how cities should adapt to become resilient to these impacts under uncertain futures. UWM challenges in the Ebbsfleet Garden City (UK) were investigated via a participatory process and potential sustainable solutions were explored using a System Dynamics Model (SDM). Collaborative development of the SDM by the Ebbsfleet Learning and Action Alliance developed stakeholders’ understanding of future UWM options and enabled a structured exploration of interdependencies within the current UWM system. Discussion by stakeholders resulted in a focus on potable water use and the development of the SDM to investigate how residential potable water consumption in the Ebbsfleet Garden City might be reduced through a range of interventions, e.g., socio-environmental and economic policy incentives. The SDM approach supports decision-making at a strategic, system-wide level, and facilitates exploration of the long-term consequences of alternative strategies, particularly those that are difficult to include in quantitative models. While an SDM can be developed by experts alone, building it collaboratively allows the process to benefit from local knowledge, resulting in a collective learning process and increased potential for adoption.

Development of maize cob‐based biochar filter for water purification

AbstractThe study aimed at biochar production from maize cob and its performance in improving water physiochemical attributes. Three feedstock masses (2, 2.5, 3 kg) were used for biochar production. Nine treatment combinations of T1L1, T1L2, T1L3, T2L1, T2L2, T2L3, T3L1, T3L2 and T3L3 in triplicate were used for biochar performance. Biochar yield of 50% was averagely achieved at slow pyrolysis conditions (300 to 600°C) and 120 min residence time. Biochar had 4.13% moisture content, 6.86% ash, 17.70% volatile matter, 71.28% fixed carbon, and a pH of 10.27. Odour, colour, and total hardness of the wastewater improved after filtration using biochar to acceptable levels for potable water use. Total hardness reduced by 51.9% in T2L2 and 44.4% in T3L2. Findings front maize cob biochar as a purification technology for domestic potable water use. There is need for maize cob biochar performance on heavy metals and when it is sandwiched with other materials.

Evaluation of Water Saving Potential for Short-Term Water Demand Management

Water shortage has become more frequent with occurrence of severe and frequent droughts and increasing water demand due to many factors, e.g., population growth and socio-economic development. Adaptive water management plans, including both supply-side and demand-side measures, provide water supply utilities guidance during water shortage situations. Among those measures, short-term demand management, e.g., water restrictions for outdoor water use, has gained increasing popularity in reducing water consumption. One key to successful implementation of short-term demand management is to evaluate water saving potential from different water user groups. Evaluation results could facilitate developing effective public messages tailored for different groups of water users. In this study, single-family water consumption in the Tampa Bay Area, located at the west coast Florida in the United States, is analyzed. Different factors including precipitation, temperature, household income and water restrictions are examined through multiple linear regression. Water use data were segregated into five sub-groups based on median household income gathered at census block group level. Analyses using aggregated data reveal potential saving from water shortage based 2-day watering per week to 1-day watering per week is very limited (< 1%), although striking differences between potable water use in distinct socio-economic groups of water users is observed. Analyses based on segregated data found that saving potential for subgroups of water uses with high household income is larger. This result provides important information for water demand managers, considering development of tailored messages for distinct groups of water users to reduce water consumption during shortages. Application of results findings in designing and implementing a water shortage mitigation plan is discussed.

Feasibility analysis of a small-scale rainwater harvesting system for drinking water production at Werrington, New South Wales, Australia

Rainwater harvesting is a well-known method of collecting and storing rainwater that can subsequently be used for different purposes. Most of the recent studies focused on how to use the harvested rainwater effectively to reduce the use of potable water for non-potable usage and ultimately cut down the water demand from the mains. However, studies on rainwater harvesting system have rarely been undertaken for drinking water production at the household level in rural areas, where a centralised water supply system is unavailable. The present study reports the feasibility of a small-scale rainwater harvesting system intended to produce drinking water for rural/isolated communities. A number of parameters such as roof size, tank size, water demand and daily filtration rate were taken into consideration to examine the performance of the rainwater harvesting system. Local meteorological and costing data were used in the study assuming that the system would provide drinking water to a typical household of four people. It is found that the small-scale rainwater harvesting system can satisfy the drinking water demand throughout the year with 90–97% reliability depending on the roof size. In addition, the capacity of monthly water production from different rainwater harvesting systems is presented that can be adopted to increase the reliability further. A life cycle cost analysis of the system is presented including sensitivity analysis. It is found that the preferred rainwater tank size for a household having 100 m2 roof area in Werrington, New South Wales is 5 kL. The system payback time falls between 1 and 6 years depending on the price of the produced drinking water. The cost of the produced drinking water including disinfection and mineral addition is found to be 1.04 AU₵/L. In addition, the intended rainwater harvesting system could result in a monetary return of AU$ 35,494 over its lifetime of 25 years. This study shows that the production of drinking water by rainwater harvesting for rural communities is possible at an affordable cost, which is aligned to the United Nation’s Sustainable Development Goal 6: Clean Water and Sanitation.

Optimize urban food production to address food deserts in regions with restricted water access

Adequate access to healthy, affordable food remains a great challenge in many urban areas. Among a range of interventions, urban agriculture has been identified as an important strategy to help address urban healthy food access. While urban food production is growing in popularity, the use of potable water in traditional urban agricultural installations will exacerbate gaps in water demand and availability in water-stressed cities. This paper examines the sustainable capability of urban agriculture through an integration of alternative water resources, urban vacant land and local nutritional needs. A spatial optimization model is developed to best allocate limited resources for maximal food production to address urban food deserts. The new model is applied to test the capability of relocalized food production in Tucson, Arizona, a semi-arid region with the longest continuously farmed landscape in North America. Results highlight that urban areas with restricted water access can substantially enhance their local food production capacity in an ecologically responsible manner.

Frequency of Animal Leptospirosis in the Southern United States and the Implications for Human Health.

Leptospirosis is a zoonotic disease with symptoms in humans and animals, ranging from subclinical to serious and fatal. The disease occurs worldwide, but there is limited recognition of the public and animal health risks it poses in the southern United States. A systematic review of the frequency of animal leptospirosis in 17 states and jurisdictions covering the southern continental United States was performed to advance our understanding of the pathogen's distribution and identify transmission patterns that could be targeted for prevention efforts. Fifty-two articles, spanning >100 years, met the analysis criteria. A wide range of techniques were used to measure seroprevalence and isolate the bacteria. The assessment identified exposure to Leptospira spp and Leptospira spp infection among a diverse range of species, spanning 22 animal families within 14 states, suggesting that the pathogen is distributed throughout the southern region. Disease frequency trends were assessed among animals in various habitats (all habitats, nonwild habitats, and wild habitats). The frequency of Leptospira spp detection in animals in wild habitats increased slightly over time (<0.2%/year). We identified reports of 11 human leptospirosis illness clusters and outbreaks in the southern United States. Exposure to potentially contaminated surface waters were documented for at least seven of the events, and interactions with infected or likely infected animals were documented for at least six of the events. This analysis highlights the need for stronger partnerships across the public and animal health fields to enhance diagnostics, surveillance, and reporting. The early identification of leptospirosis in animals may serve as an indicator of environmental contamination and trigger prevention measures, such as vaccinating companion animals and livestock, use of potable water, and the wearing of waterproof protective clothing near water that may be contaminated.

Urban water supply system optimization and planning: Bi-objective optimization and system dynamics methods

Sustainable, low-cost, environmentally conscious development is a major challenge for urban water supply systems. This study considers household and industrial water demand and establishes a bi-objective model to balance the economic and environmental cost of a three-stage urban water supply system including water production, distribution, and treatment processes. Considering different attitudes toward the increasing imbalance between water demand and supply, three hypothetical scenarios are designed based on which three sets of data on water demand and wastewater production volumes are defined. Then, a two-step method is applied to obtain solutions to decision variables (potable water use rate and wastewater untreated rate). After optimization, a system dynamics model is applied to test water supply system performance under short-, medium-, and long-term planning scenarios. Finally, the model is applied to Singapore to test its feasibility. The proposed bi-objective model provides managerial insights into the use of alternative water resources. For example, in 2020, water demand is simulated as 5.63×108m3. After optimization using the proposed model, the quantity of alternative water is 2.5×108m3 (water from the local catchment), 2.5×108m3 (imported water), 5.31×107m3 (desalinated water), 4.05×107m3 (NEWater for indirect potable use), and 8.10×107m3 (NEWater for direct non-potable use). Total water supply is 6.75×108m3, which means there is some redundancy in water supply. Further, three indexes—supply-demand ratio, economic cost, and environmental cost—help to identify the suitable planning period: the medium-term focus is the most appropriate option as it promises water adequacy for over 15 years and has lower energy costs and less negative environmental impact during the evaluation years. In addition, this study proves the influence of decision makers’ preferences on contradictory objective functions (economic cost minimization and environmental negative impact minimization). Overall, the proposed model balances a trade-off between the risk of an increasing future supply-demand imbalance and current water adequacy. Lastly, the proposed model offers a paradigm to identify a sustainable planning period.

A GHG Metric Methodology to Assess Onsite Buildings Non-Potable Water System for Outdoor Landscape Use

This paper documents a water:energy greenhouse gas (GHG) metric methodology for a decentralized non-potable water system that was developed as part of a Professional Doctorate in Engineering (DEng) research project by the first author. The project identified the need to investigate the challenges in changing the use of potable water to recycled water for landscape irrigation (LI) and for water features (WFs) at a medical facility case study (MFCS) in Abu Dhabi (AD) (the capital city of the United Arab Emirates (UAE). The drivers for the research project were based on the need for AD to decrease desalinated potable water as well as reduce the environmental impact and operational costs associated with the processing and use of desalinated water. Thus, the aim of the research discussed and presented in this paper was to measure the impact of using recycled and onsite non-potable water sources at the MFCS to alleviate the use of desalinated potable water and reduce associated energy consumption, operational costs, and GHG emissions (latterly in terms of carbon dioxide equivalent (CO2e), for LI and WFs. The analysis of three case scenarios at the MFCS compared different approaches to alleviate energy use, costs, and GHG impacts for the use of recycled water in LI and WFs against a baseline. The findings led to a proposed sustainable water conservation and reuse (SWC) strategy, which helped save 50% desalinated potable water for LI use by soil improvement, building water system audits, and alternate non-potable water reuse. The recommendations for this paper are to develop a SWC strategy forming the basis for a water protocol by the competent authority for regional medical facilities including an assessment methodology for building decentralized non-potable water systems to measure their energy, GHG emissions and financial impact.

Increased Dissolved Organic Carbon Concentrations in Peat‐Fed UK Water Supplies Under Future Climate and Sulfate Deposition Scenarios

AbstractPeatlands are globally‐important terrestrial carbon stores as well as regional sources of potable water supply. Water draining from peatlands is rich in dissolved organic carbon (DOC), which can be problematic for water treatment. However, it is unclear how future climate and sulfate deposition changes may impact DOC in peatland‐derived potable water. The United Kingdom (UK) is a global hotspot that consumes 79% of all potable water derived directly from peatlands. Here, a physically‐based hydrological model and a biogeochemical organic carbon model were used to predict discharge and DOC concentration in nine hotspots of peatland‐derived potable water use in the UK under a range of 21st century climate and sulfate deposition scenarios. These nine catchments supply 72% of all peatland‐derived water consumed in the UK and 57% of the global total, equivalent to the total domestic consumption of over 14 million people. Our simulations indicate that annual discharges will decrease and that mean annual DOC concentrations will increase under all future scenarios (by as much as 53.4% annually for the highest emissions scenario) in all catchments. Large increases (by as much as a factor of 1.6) in DOC concentration in the 2090s over the baseline period are projected for autumn and winter, seasons when DOC concentrations are already high in the baseline datasets such that water treatment works often reach their capacity to cope. The total DOC flux is largely insensitive to future climate change because the projected increase in DOC concentration is mostly counterbalanced by the projected decrease in discharge.

Removing arsenic and co-occurring contaminants from drinking water by full-scale ion exchange and point-of-use/point-of-entry reverse osmosis systems

This study investigated the performance of two full-scale ion exchange (IX) systems, one point-of-entry (POE) reverse osmosis (RO) system and nine point-of-use (POU) RO units for simultaneous removal of arsenic and several co-occurring contaminants from drinking water. The study was performed as part of the U.S. Environmental Protection Agency’s Arsenic Treatment Demonstration Program. The IX systems, with strong base anionic (SBA) resins, effectively removed arsenic (As), nitrate (NO3−) and uranium (U) to below respective maximum contaminant levels and vanadium (V) and molybdenum (Mo) to below 2 μg/L. The useful run length, as determined by either 10-mg/L (as N) nitrate or 10-μg/L arsenic breakthrough, was approximately 400 bed volumes (BV) initially. However, it was decreased over time, e.g., by 15% in 13 months at one site and 33% in 7 months at another site, apparently caused by resin fouling due to the presence of 2-mg/L natural organic matter (NOM) in source waters. The use of dual resins ‒ an acrylic SBA resin underlain by a polystyrene SBA resin ‒ effectively removed NOM and allowed the system to perform at its baseline level through the 13-month study. Arsenic and nitrate peaking occurred when the resins were not regenerated timely. The removal of contaminants appeared to follow a selectivity sequence: U, Mo > V > SO42− > HAsO42− > NO3− > HCO3−. RO effectively removed arsenic, nitrate, antimony, uranium and vanadium, mostly with a >99% rejection rate. The POE RO coupled with dual plumbing (only treating a fraction of water for potable use) and POU RO in individual homes could be used as low-cost alternatives to traditional RO treatment.

Diseño de un Sistema de Aprovechamiento de Agua Lluvia bajo criterios de Eficiencia Hídrica en Edificios. Caso de estudio: Edificio de Clases y Laboratorio de Hidráulica de la Facultad de Ingeniería, Ciencias Físicas y Matemática de la Universidad Central

El agua es uno de los recursos naturales indispensables para el desarrollo de la vida. Lamentablemente, la condición de recurso renovable es muy cuestionada. Ecuador es uno de los países de América del Sur con mayor número de fuentes de agua dulce superficiales y subterráneas considerando su área continental. Sin embargo, existen factores influyentes que afectan la disponibilidad del agua dulce como recurso natural y que ponen en riesgo el volumen de estas reservas. El crecimiento exponencial de las poblaciones, el inclemente cambio climático, la falta de leyes y mecanismos de control para el uso responsable de agua potable y en especial, la escasez de cultura sobre la aplicación de prácticas responsables para el uso de agua potable en edificios, hace que este recurso se agote rápidamente. Las cifras estadísticas indican datos alarmantes de Ecuador con respecto a los países de la región, ya que es el mayor consumidor de agua potable con dotaciones que superan los 237 litros/(habitante.día). Esta realidad hace imprescindible que se reduzcan los consumos de agua potable en edificios para mejorar su eficiencia hídrica y convertirlos en proyectos autosustentables sin afectar la sensación de confort en los usuarios. El principal objetivo de este trabajo es el de presentar los resultados obtenidos sobre al análisis de eficiencia hídrica en edificios universitarios de Quito a través de metodologías de cálculo internacionales como la sugerida por la “ANQIP - Associação Nacional para a Qualidade nas Instalações Prediais”, de Portugal. Se concluye que, la instalación de un sistema de aprovechamiento de agua lluvia reducirá considerablemente los consumos de agua potable en un edificio con bajo desempeño hidráulico. El presente estudio se da como tema de investigación de Maestría en el Instituto Politécnico de Leiria y la Universidad Central del Ecuador.