Question

2. (10 points) A groundwater in California has the following water quality characteristics. From the analysis shown below, determine the total hardness, carbonate hardness and noncarbonate hardness of the groundwater. Express your answers in units of mg/L as CaCO3 and as meq/L. Constituent Units Concentration or Value 10 90 40 30 10 3.1 Carbon Dioxide (CO2) Calcium (Ca2+) Magnesium( Mg2+) Sodium (Na) Potassium (K) Iron (Fe+2) Manganese (Mn+2) Bicarbonate (HCO3-) Sulfate (SO424) Chloride (C1) Fluoride (F) Nitrate (NO3-) Silica (SiO2) Dissolved Oxygen (DO) Total Organic Carbon (TOC) Total Dissolved Solids (TDS) 1.3 380 40 60 mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L 1.5 15 20 4.5 6.2 440 pH 6.9 10 Temperature °C 3. (6 points) For the California groundwater in Problem 2 above, use the Langelier Saturation Index to predict whether the water will deposit (oversaturated) or dissolve (undersaturated) CaCO3. What is the pH at saturation with respect to CaCO3?
Based on question 2, how would you go about solving question number 9? Please solve question number 2 and 3 if possible.

Answer 1

Lotal Hardness ef,wp. of Cambo Mall gowl of CACO Marx equot of lacos J" 03. wt at mg" +6" (quivirlewit ust. Calog I Total Hardness = 40 x 50 +90 x 50 + 3.1 X 2 1 = 1397.2.2. m/) = 37.32 mm 37.94 mei > Alkalinity= [HC0j]x Cz. ust. of Carans + [ou]xy Tx eq. wt of G Co, eg. wt of H(0," egent of oH = 390 X NOTE: PH = 6.9 ->-17(4) = 6.9 =>(HT):1067 = 311.47 mil - 311-47 mill 16.23men ! =>(OH) = 1019 10-big 50 mg /H] = 1076mg/L mey Carbonate Hardness CH = minimum [Total Hardness. Alkalinity / CH = minimum [317.22 , 311.477 CH = 1311.47 mg/L) or CH = 16.23 meg | Nom carbonate Mardness NCH = TH. - .CH NCH = 397.22 - 31.47 NCH = 185.75 mg / NCH = 85.75 m / 1.71 mer