Assessing Methods for Analyzing Total Dissolved Solids: Looking into Water Samples from the Root River in Racine County, WI
Mentor 1
Charles Paradis
Start Date
28-4-2023 12:00 AM
Description
Total dissolved solids (TDS) is a measurement (mg/L) of the amount of organic and inorganic materials such as salt, ions, and minerals that are dissolved in a volume of water. TDS concentrations are known to fluctuate between water sources including road salt runoff, agricultural runoff, and sewage treatment effluent. Freshwater TDS values should be less than 1,000 mg/L, values that exceed this are considered brackish waters (1,000-10,000 mg/L). TDS analysis was added to the Road Salt Transport research to aid in the understanding of the chloride (Cl-) mass discharge on the Root River. Two methods were applied to quantify TDS, an assessment was conducted to compare the two methods, highlighting the accurate and consistent method. The two methods compared were (1) mass balance and (2) conductivity probe. The mass balance method consists of measuring the volume of water before placing it into an oven at 180°C. The sample evaporates for 12 hours and then the left-over crust is measured directly for a TDS value. The conductivity probe indirectly measures TDS, using a calibration curve. This curve was calculated by a set of Cl standard solutions, ranging from 0 – 2,000 mg/L, providing conductance values (mS/cm) for known Cl concentrations (mg/L). A linear regression and an equation was then established from this data and used to convert conductance values into chloride values. Water samples were measured using the conductivity probe, producing conductance values that were later converted into chloride concentration values. The two methods were assessed using various criteria; overall time to complete a method, materials, costs, and most importantly accuracy and consistency. Results show that method (2) conductivity probe, performed better than method (1) mass balance. The conductivity probe was then used to quantify TDS data on all future samples collected between 06/06/22 - 08/24/22.
Assessing Methods for Analyzing Total Dissolved Solids: Looking into Water Samples from the Root River in Racine County, WI
Total dissolved solids (TDS) is a measurement (mg/L) of the amount of organic and inorganic materials such as salt, ions, and minerals that are dissolved in a volume of water. TDS concentrations are known to fluctuate between water sources including road salt runoff, agricultural runoff, and sewage treatment effluent. Freshwater TDS values should be less than 1,000 mg/L, values that exceed this are considered brackish waters (1,000-10,000 mg/L). TDS analysis was added to the Road Salt Transport research to aid in the understanding of the chloride (Cl-) mass discharge on the Root River. Two methods were applied to quantify TDS, an assessment was conducted to compare the two methods, highlighting the accurate and consistent method. The two methods compared were (1) mass balance and (2) conductivity probe. The mass balance method consists of measuring the volume of water before placing it into an oven at 180°C. The sample evaporates for 12 hours and then the left-over crust is measured directly for a TDS value. The conductivity probe indirectly measures TDS, using a calibration curve. This curve was calculated by a set of Cl standard solutions, ranging from 0 – 2,000 mg/L, providing conductance values (mS/cm) for known Cl concentrations (mg/L). A linear regression and an equation was then established from this data and used to convert conductance values into chloride values. Water samples were measured using the conductivity probe, producing conductance values that were later converted into chloride concentration values. The two methods were assessed using various criteria; overall time to complete a method, materials, costs, and most importantly accuracy and consistency. Results show that method (2) conductivity probe, performed better than method (1) mass balance. The conductivity probe was then used to quantify TDS data on all future samples collected between 06/06/22 - 08/24/22.
