ENGINEERING SCIENCE DEPARTMENT
Water and Environmental Technology Program
Name _________________
SPRING TERM
Aquatic Chemistry II, WQT-134
Final review Sheet
Lab 1 Acidity
Titrant: 0.02 N sodium hydroxide
Indicator: phenolphthalein for pH 8.3
Formula: Acidity CaCO3/L= (A X B) X 50,000
ml of sample
A = mL NaOH titrant used,
B = normality of NaOH,
Units: The acidity to pH _______ = _______ mg CaCO3/L.’’
Ranges: 10:1 acidity to alkalinity = good digestor, 5:1 ratio= bad digestor .
Lab 2 Alkalinity
Titrant: 0.02 N Standard sulfuric acid
Indicator: Mixed
bromcresol green-methyl red indicator solution starts at blue green and goes to
reddish pink at pH 4.5:
phenolphthalein for pH 8.3
Formula: P
Alkalinity mg/L as CaCO3/L=
(ml of acid to 8.3 or colorless )(Normality)(50 mg/meq as CaCO3)(1000 ml)
ml of original sample volume
T Alkalinity mg/L as CaCO3/L=
(ml of acid to 8.3=colorless+ ml to reach pH 4.5=pink)(Normality)(50mg/meq CaCO3)(1000 ml)
ml of original sample volume
Units: "p" alk. =
mg/L as CaCO3: "t" alk. =
mg/L as CaCO3
Ranges: Properly operating anaerobic digesters typically have supernatant alkalinities
in the range
of 2000 to 4000 mg calcium carbonate (CaCO3)/L.
Lab 3 calcium carbonate saturation
Titrant: 0.02 N Standard sulfuric acid
Indicator: Mixed
bromcresol green-methyl red indicator solution starts at blue green and goes to
reddish pink at pH 4.5:
phenolphthalein for pH 8.3
Formula: Step
1 A= samples prior to saturation
B= samples after saturation
Eq 1: A-B= Stability Index
Eq 2: Alk(1)-Alk(2)= +, -, 0
Eq 3: pH(1) – pH(2)= +, -, 0
Ranges: A>B- water is supersaturated with respect to carbonate and may forma
precipitate scale
A<B water is undersaturated with respect to carbonate and may be corrosive
A=B water is in equilibrium with respect to carbonate constituents
Units: =
mg/L as CaCO3
Lab 4 Conductivity
Instrument: sension probe
Std: Hach 1000 s/cm sodium
Units: = Conductivity=
chloride standard solution
__________ µmhos/cm TDS =_______ mg/L as CaCO3
Lab 5 Hardness
Titrant: 0.01
M EDTA
Indicator: Eriochrome
Formula/Units :
Black T indicator
Hardness as CaCO3 mg/L=
(ml of EDTA (sample) – ml of EDTA (blank))(0.01 M EDTA)(100 mg=CaCO3 milliMole)(1000 ml/L)
ml of sample volume titrated
Range: >180 mg/L hard
Lab 6 Fe
Instrument: Spectrophotometer,
Buffer: Ammonium
for use at 510 nm
acetate buffer solution pH(4)
Standards: Hydroxylamine solution or ferrous ammonium sulfate
Indicator: Phenanthroline solution
Formula/Units : need a calibration curve with a regression line to determine
concentrations
Calibration curve:
Total Fe 510 nm STM 4500 (5-23-07)
y = 0.1788x + 0.0605
Absorbance (nm)
1
2
R = 0.9937
0.8
0.6
Total Fe
0.4
Linear (Total Fe)
0.2
0
0
1
2
3
4
5
Concentration (mg/L)
Lab 7 Jar Testing
Instrument: Phipps
Standards: Alum
and Bird flocculator
(fast mix and then slow mix), turbidity, color, pH
unknown
Lab 8 Chlorine demand
Instrument: HACH DR 100 Colorimeter
Sample additives: Hach DPB Free Chlorine Powder
Pillow or Hach DPB Total Chlorine Powder
Pillow
Standards: Standard chlorine solutions 1mg=1ml from bleach
Dosage=Demand +Residual
Chlorine demand, mg/L = (DS − RS) − (DB − RB)
Formula/Units:
where Rs = residual after contact time, must meet the following criteria
1) Rs<Ds-1.4Rmin
2) Rs>Rmin and
3) Dose is ,most similar to normal doasage expected in field
Ds = dose, mg/L
Rmin= minimal residual measurable by the method (~0.05 mg/L)
DB= residual of blank after contact time, mg/L, and
DB = blank dose, mg/L
Lab 9 DO
Instrument Hach Ion Sension 6 Dissolved Oxygen Meter
Sample additives: DO reference electrolyte
Formula/Units: DO = ____ mg/L Range: < 5 bad, 10 mg/L = ok
Lab
Titrant
Lab 1
Acidity
and pH
Lab 2
Alkalinity
Lab 3
Calcium
Carbonate
Saturation
Lab 4
Hardness
Lab 5 Fe
Lab 6 Jar
Testing
(color +
turbidity)
Lab 7
Chlorine
Demand
Lab8
Dissolved
Oxygen
MISC
Mean
Statistics
& Math,
Sampling
Indicators Problems/Interferences Advantages FORMULA Units Mcl?
Median
Mode
Precision?
Accuracy?
RSD?