Grantee Research Project Results
2015 Progress Report: Point Of Use (POU) Water Treatment Systems For Improving Sustainability And Environmental Justice in Colonias of the Paso del Norte Region
EPA Grant Number: R835179Title: Point Of Use (POU) Water Treatment Systems For Improving Sustainability And Environmental Justice in Colonias of the Paso del Norte Region
Investigators: Walker, W. Shane , Palacios, Rebecca L. , Santiago, Ivonne , Tomaka, Joe , Walton, John
Institution: The University of Texas at El Paso , New Mexico State University - Main Campus
EPA Project Officer: Page, Angela
Project Period: December 1, 2011 through November 30, 2016
Project Period Covered by this Report: December 1, 2014 through November 30,2015
Project Amount: $498,906
RFA: Research and Demonstration of Innovative Drinking Water Treatment Technologies in Small Systems (2011) RFA Text | Recipients Lists
Research Category: Drinking Water , Water
Objective:
The objectives of this project are to: perform community-based participatory research (CBPR) through Water and Point of Use (POU) Perception and Use Inventory surveys of residents in up to 12 colonias of the Paso del Norte region; design and test POU systems for specific water contaminants of these colonias; implement select POU systems in over 100 homes across at least three colonias: and evaluate the sustainability of the use of POU technologies with respect to environmental, social/user, and economic metrics.
Colonias are unincorporated settlements along the U.S.-Mexico border, which emerged without the governance and public infrastructure normally provided by local government. Consequently, water lines and systems do not reach all colonia residents, and even when they do reach, many residents live in substandard housing that does not meet county building codes and, therefore, do not qualify for access to public water. Alternative water sources for these colonia households include water wells and hauled water stored in tanks.
Progress Summary:
Phase 1 – Colonia Selection and Engagement – Completed (reported February 28, 2014)
Phase 2 – POU Screening – Completed
Task 1 - POU review and selection: Completed (reported February 28, 2014)
Task 2 - Water sampling and quality analysis: Completed
Methods. Fourteen households who rely on wells were sampled, as well as eight households who have their water hauled to them. Total dissolved solids were measured according to SM 2540C. Anions and cations were analyzed using a Dionex simultaneous system consisting of an ICS-1100 unit with an IonPack™ CS16 column for cations and an ICS-2100 with an IonPack™ AS18 for anions (SM 4110B). Dissolved arsenic, iron, and manganese were measured by spectrophotometry with a Perkin Elmer Optima 7300 DV (SM 3120B). Arsenic has been reported to be present in wells throughout the southwest United States and, according to the focus groups that were conducted in this study, iron and manganese can precipitate within a house’s plumbing or appliances. All samples introduced to the ICP were filtered and acidified with 2% nitric acid (v/v). Conductivity (SM 2510B), pH (SM 4500-H+B,) temperature (SM 2550B), and oxidation reduction potential (SM 2580B) were measured in the field using a Myron L Ultrameter II™ as soon as the samples were collected. Alkalinity was measured using a MicroLab automatic titrator and sulfuric acid. Free chlorine was also measured in the field following (SM 4500-ClG). Total coliforms and Escherichia coli were analyzed using IDEXX’s Colilert®-18 method and reagents (SM 9221C). Water quality results were analyzed using Minitab 17 Minitab Inc (2013).
Results. High concentrations of TDS can increase mortality from all categories of ischaemic heart disease and acute myocardial infarction (World Health Organization, 2003). For households relying on well water, 79% of the samples exceeded EPA’s secondary limit of 500 mg/L TDS (40 CFR §143.3), and 50% of the samples exceeded the secondary limit of 1,000 mg/L TDS recommended by New Mexico Environment Department (NMED) and Texas Commission on Environmental Quality (TCEQ) (NMAC 20.6.2.3103, 2002) (30 TAC §290.105). In households with hauled water, 50% of houses had TDS exceeding EPA’s secondary limit of 500 mg/L, and none of the samples exceeded the states’ secondary limit of 1,000 mg/L. These results indicate that desalination treatment would be necessary in most colonia households to reduce TDS concentrations to comply with the EPA secondary limit. With respect to sulfate (not shown), more than 75% of samples from wells were above EPA’s and TCEQ’s secondary limits (250 mg/L and 300 mg/L, respectively), while none of the samples from hauled water were above EPA’s secondary limit. Ingestion of large quantities of sulfate can cause purgation (World Health Organization, 2004). Hard water and sulfates can decrease the useful life of some appliances and boilers.
Task 3 - Laboratory testing of POU treatment systems: Completed
Methods. A test skid was assembled with two different brands of RO membrane water filters in order to compare them. The commercially available models were General Electric (GE) GXRM10 RBL, and the Whirlpool WHER25 from Home Depot and Lowe, respectively. The feed water for the systems was taken from one of the laboratory faucets, with the flow divided between the two. Each system line had pressure gauges installed to compare the relationship between pressure and recovery ratio. Flowrate for the feed, concentrate and permeate lines was measured using a graduated beaker and a timer. Both filters were in operation from April 27 to June 21, 2016 (9 weeks). Flowrates for the feed and the permeate were measured five times per week at four different pressures (20, 25, 30 and 35 psi) to observe the sensitivity of the hydraulic recovery. (That is, an increase in the pressure increased the permeate flowrate and the hydraulic recovery). Flowrate readings were taken on a daily basis in order to calculate the recovery of each system. Throughout the 9 weeks of operation, different pressures were applied to the systems in order to compare the performance of such systems while working under different pressure. Once per week, samples were collected from the feed water, the concentrate, and the permeate from each system. Two different samples were taken from each of these sources. One sample was stored in an IDEXX sterile bottle with sodium thiosulfate for MPN. The second sample was collected in a 500 mL polyethylene bottle.
Results. The Whirlpool RO unit showed higher permeate flowrate and hydraulic recovery than the GE. If a colonia household has low water pressure, the Whirlpool POU would be preferred. With respect to water quality, no objectionable differences in performance were observed between the GE and Whirlpool systems.
Phase 3 – Implementation
Task 1 - POU implementation: Ongoing
A 12-month no-cost extension was requested to complete this work, and the request was approved by NCER. The research protocol to engage human subjects in controlled exposure to drinking water from commercially available point of use drinking water filters has been approved by UTEP IRB and EPA NCER IRB. (EPA NCER IRB explicitly forbids controlled exposure research in households with children, pregnant women, or nursing women.) In summary, households who qualify and agree to participate complete a survey before and after installation of a POU RO system under their kitchen sink.
Methods. Families from several colonias located in the outskirts of the City of El Paso were contacted in accordance to the protocol (IRB Net ID 483287) that was approved by the institutional review boards (IRBs) of UTEP, NMSU, and EPA. Focus groups met in a previous stage of the project, providing researchers with the contact information. The recruiting of participants was through different associations, mainly: Familias Triunfadoras Inc. and Adult & Youth United Development Association, Inc. (A.Y.U.D.A., Inc.). Families were contacted, and the research project was explained to them. In order to participate, families had to satisfy EPA’s controlled exposure requirements, which excludes: children under the age of eighteen, pregnant women, and nursing women. For the people who qualified and agreed to participate, a consent form was completed. Researchers then administered a pre-implementation questionnaire which is not covered in this report.
Results. In the exposition at the USA Science & Engineering Festival As of December 1, 2016, 22 households agreed to participate in the project. Filters were installed in 20 of them, and the installation was cancelled for two of them because they had children (thus not satisfying EPA’s controlled exposure restrictions). These installations took place in five different colonias: Anthony and Vinton in Doña Ana County, and Agua Dulce, Fabens, and Tornillo in El Paso County. The colonias located in New Mexico predominantly rely on domestic wells for their water supply. Agua Dulce residents have their water hauled to them, while Fabens and Tornillo are small public water systems with arsenic above the EPA MCL.
Task 2 - Water sampling and quality analysis: Ongoing
Methods. Source water and drinking water samples are being collected at each household and analyzed for water quality parameters such as pH, total dissolved solids, conductivity, major ion composition by ion chromatography, metals by ICP, and MPN for coliforms and E. coli.
Results. Of the 20 systems installed, water quality analyses for both tap and RO water samples were completed for seven households (three GE systems and four Whirlpool). All product water quality parameters met EPA primary and secondary drinking water requirements. Comparison of GE and Whirlpool brands showed less than 1% difference in rejection of conductivity, TDS, arsenic, magnesium, and sulfate.
Phase 4 – Evaluations
Task 1 - POU Evaluations: Ongoing
In addition to confirming the technical and water quality performance of the POUs, an extensive survey of water quantity, quality, use, and perception is used to observe the residents' conditions before and after implementation and to evaluate the effectiveness of the POUs. The pre-implementation questionnaire is divided into six sections regarding: (1) the household’s water consumption and approach to their water, (2) perception of water quality, (3) information about water that they acquire for drinking, (4) information regarding hauled water, (5) information regarding domestic wells, and (6) demographics. A post-implementation survey is administered 1 to 2 months after installation of the POU.
Task 2 – Sustainability Evaluation: Completed
Methods. A ranking system for POUs and POEs must consider the following aspects: (1) the technical performance of the unit with respect to removing contaminants and providing adequate drinking water quality; (2) the verification of reliable performance; (3) user preferences for unit operation; (4) the economic costs of the unit; (5) and the environmental impacts (pollution) of the unit. The simplest form of aggregation, a summation without weights, was employed to compute the total score for each water treatment unit:
Sustainability = Performance + Verification + Preference + Affordability + Environmental
Results. A list of 38 point of use (POU) water treatment units reviewed in this research, and the GE and Whirlpool POUs that are being installed in the colonias were tied at the highest rank.
Task 3 - Reporting: Ongoing
One journal paper manuscript has been accepted for publication, and several other manuscripts are in preparation.
Future Activities:
Year 5 will include completion of the implementation (Phase 3) and evaluation (Phase 4) portions of this study.
Journal Articles:
No journal articles submitted with this report: View all 10 publications for this projectSupplemental Keywords:
Drinking water, small systems, colonias, hauled water, groundwater, point of use treatment, membrane filtrationProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.