Understanding Water Quality Challenges in El Paso's Aquatic
School
Virginia Tech**We aren't endorsed by this school
Course
CEE 5104
Subject
Biology
Date
Dec 11, 2024
Pages
4
Uploaded by MinisterPenguin4814
CEE 5104 Water Quality ProjectInvestigate the aquatic chemistry of a documented drinking water quality challenge.In this summary, I will focus on the chemical aspects of the El Paso, Texas water quality issue that Professor Sedlak discussed. *chemanalysis.pdf (civiclive.com)Seven blended sources supply the city, and the distribution system may transmit water from one source to another. These sources are usually distributed as follows in the city: Sources include Upper Valley, Northwest, West, Downtown Central, Airport Central, Northeast, East, Far East, and Lower Valley. Each source supplies the following areas: Water is continually mixed in these regions because water supply ratios change. Overall, hardness averages 175 mg/L or 10.2 grains per gallon. A 0.5 to 1.5 mg/L chlorine residual prevents tastes and odors and disinfects water. Preventing waterborne sickness from bacteria, protozoa, and viruses requires disinfection.
Although brackish groundwater in El Paso, Texas, is a substantial source of drinking water, it is undrinkable due to high concentrations of dissolved salts. However, a $90 million desalination plant was constructed in 2007 due to the expanding Metro area and reverse osmosis membrane technology advances.[1]Drinking water analysis for Inorganics, radioactive and unregulated contaminants, disinfection byproducts and residuals, and Total organic carbon are mentioned in the following table.*dwr_2022.pdf (civiclive.com).
Toxicity issues with drinking water are not limited to the more prevalent components like iron and chlorine. Common contaminants in drinking water include arsenic, chromium, and lead. Because of their widespread use in industry, these chemicals frequently get into our drinking water. Lead pipes, which melt at 327.5ºC, have a long and storied history of connecting people to safe drinking water.Chronic lead poisoning affected a sizable percentage of the populace in regions low in carbonate. The divalent lead corrosion layer was oxidized to tetravalent lead oxide when American communities added chlorine to their drinking water in the early 20th century. Changing the pH and adding phosphate to make lead phosphate minerals are only two of the many treatments that have been tested.The Southmost brackish ground-water RO plant in Brownsville, Texas, has produced 7.5 MGD for 50 years since 2004. Located between Brownsville and the Gulf of Mexico, the plant uses 3500 ppm Gulf Coast aquifer brackish groundwater, lowering drinking water salinity to 300-475 ppm below the EPA limit. The plant meets the Texas Commission on Environmental Quality's 35,339 mg/L daily TDS standard. The plant's production efficiency has improved from 13% in 2004 to 94%. The facility cost $29 million to build and $3 million to operate and maintain in 2014. The plant introduced 12 MGD microfiltration membranes for arsenic and iron removal in the RO process.The facility is meant to last, yet economic feasibility needs periodic capital replacement expenditures.[2]Balanced Chemical Equation for the Dissolution of CaCO3:CaCO3(s) -> Ca²⁺(aq) + CO₃²⁻(aq)Calculate the standard enthalpy change (ΔH°) using standard enthalpy of formation values for the substances involved:ΔH°f(CaCO3) = -1206.92 kJ/mol (standard enthalpy of formation of CaCO3)
ΔH°ff(Ca²⁺) = -542.92 kJ/mol (standard enthalpy of formation of Ca²⁺ions)ΔH°f(CO₃²⁻) = -676.26 kJ/mol (standard enthalpy of formation of CO₃²⁻ions)ΔH°f rxn = Σ ΔH°f(products) - Σ ΔH°f(reactants)ΔH°frxn = [1 × ΔH°f(Ca²⁺) + 1 × ΔH°f(CO₃²⁻)] - [1 × ΔH°f(CaCO3)]ΔH°frxn = [1 × (-542.92 kJ/mol) + 1 × (-676.26 kJ/mol)] - [1 × (-1206.92 kJ/mol)]ΔH°frxn = (-542.92 kJ/mol – 676.26 kJ/mol) - (-1206.92 kJ/mol) = -12.26 kJ/mol.Now, calculate ΔGf°:ΔG°f rxn = Σ ΔG°f(products) - Σ ΔG°f(reactants)ΔG°f rxn = [1 × ΔG°f(Ca²⁺) + 1 × ΔG°f(CO₃²⁻)] - [1 × ΔG°f(CaCO3)]ΔG°frxn = [1 × (-553.04 kJ/mol) + 1 × (-528.1 kJ/mol)] - [1 × (-1128.79 kJ/mol)]ΔG°frxn = 47.65 kJ/molBibliography 1.Ahdab, Y.D. and J.H. Lienhard, Chapter 41 - Desalination of brackish groundwater to improve water quality and water supply, in Global Groundwater, A. Mukherjee, et al., Editors. 2021, Elsevier. p. 559-575.2.Ziolkowska, J.R. and R. Reyes, Chapter 3.1.3 - Prospects for Desalination in the United States—Experiences From California, Florida, and Texas, in Competition for Water Resources, J.R. Ziolkowska and J.M. Peterson, Editors. 2017, Elsevier. p. 298-316.