# Hardness Removal

Topics: Water, Hard water, Calcium Pages: 3 (727 words) Published: March 24, 2013
Lab X3: Hardness Removal
The objective of the experiment was to remove water hardness through the use of different methods such as: chemical addition, flocculation, and settling. Equipment Used:
Buret
150 mL beaker
1-2L jar
Filter paper, funnel
Stir bar, magnetic stirrer
Rapid mix reactor
Stop watch
Fisherbrand 100-1000μL digital pipet – serial number: DH94800 pH indicator paper
Experimental conditions – 74.6 ̊ F

Data and Analysis

Table 1: Parameters of untreated water|
pH| ALK total (mg/L as CaCO3)| TH (mg/L as CaCO3)| Calcium hardness (mg/L as CaCO3)| Magnesium hardness (mg/L as CaCO3)| 6.99| 188| 328| 296| 32|

Table 2: Data for hardness and other parameters of softened water| pH| Starting position (mL)| Ending position (mL)| Volume of 0.0100M EDTA for total hardness titration (mL)| Starting position (mL)| Ending position (mL)| Volume of 0.0100M EDTA for calcium hardness titration (mL)| 7| 0.00| 4.20| 4.20| 6.90| 9.85| 2.95|

Calculations for softened water:

Total Hardness = 4.20 mL 0.0100 M EDTA50 mL (sample)*1000 mL1 L*1 mg CaCO31 mL 0.0100 M EDTA=84 mgLCaCO3

Calcium Hardness = 2.95 mL 0.0100 M EDTA50 mL (sample)*1000 mL1 L*1 mg CaCO31 mL 0.0100 M EDTA=59 mgLCaCO3

Magnesium Hardness = 84 mgLCaCO3-59 mgLCaCO3= 25 mgLCaCO3

Questions:
1) Based on this experiment what additional step is needed to make the water suitable for human consumption?

2) What was the percentage removal of total hardness, calcium, and magnesium? The percentage removal for total hardness was 74.39%, for Calcium 80.06%, and for Magnesium 21.88%. Total Hardness Percentage Removal = 100-84328*100=74.39 %

Calcium Percentage Removal = 100-59296*100=80.06%
Magnesium Percentage Removal = 100-2532*100=21.88%

3) How close did the treatment process come to reaching the practical limits of hardness reduction? Hardness removal limits were not achieved. Calcium was reduced to a...